Subcutaneous pedicle propeller flap: An old technique revisited and modified!

PubMed Central

Karki, Durga; Mehta, Nikhil; Narayan, Ravi Prakash

2016-01-01

Background: Post-burn axillary and elbow scar contracture is a challenging problem to the reconstructive surgeon owing to the wide range of abduction and extension that should be achieved, respectively, while treating either of the joint. The aim of this paper is to highlight the use of subcutaneous pedicle propeller flap for the management of post-burn axillary and elbow contractures. Methodology: This is a prospective case study of axillary and elbow contractures managed at a tertiary care hospital using propeller flap based on subcutaneous pedicle from 2009 to 2014. Surgical treatment comprised of subcutaneous-based pedicle propeller flap from the normal tissue within the contracture based on central axis pedicle. The flap was rotated axially to break the contracture. The technique further encompassed a modification, a Zig-Zag incision of the flap, which was seen to prevent hypertrophy along the incision line. There was a mean period of 12 months of follow-up. Results: Thirty-eight patients consisting of 22 males and 16 females were included in this study among which 23 patients had Type II axillary contractures and 15 had moderate flexion contractures at elbow joint. The post-operative abduction achieved at shoulder joint had a mean of 168° whereas extension achieved at elbow had a mean of 175°. The functional and aesthetic results were satisfactory. Conclusion: The choice of surgical procedure for reconstruction of post-burn upper extremity contractures should be made according to the pattern of scar contracture and the state of surrounding skin. The choice of subcutaneous pedicle propeller flap should be emphasised because of the superior functional results of flap as well as ease to learn it. Moreover, the modification of propeller flap described achieves better results in terms of scar healing. There is an inter-positioning of healthy skin in between the graft, so it prevents scar band formation all around the flap. PMID:27833285

Subcutaneous pedicle propeller flap: An old technique revisited and modified!

PubMed

Karki, Durga; Mehta, Nikhil; Narayan, Ravi Prakash

2016-01-01

Post-burn axillary and elbow scar contracture is a challenging problem to the reconstructive surgeon owing to the wide range of abduction and extension that should be achieved, respectively, while treating either of the joint. The aim of this paper is to highlight the use of subcutaneous pedicle propeller flap for the management of post-burn axillary and elbow contractures. This is a prospective case study of axillary and elbow contractures managed at a tertiary care hospital using propeller flap based on subcutaneous pedicle from 2009 to 2014. Surgical treatment comprised of subcutaneous-based pedicle propeller flap from the normal tissue within the contracture based on central axis pedicle. The flap was rotated axially to break the contracture. The technique further encompassed a modification, a Zig-Zag incision of the flap, which was seen to prevent hypertrophy along the incision line. There was a mean period of 12 months of follow-up. Thirty-eight patients consisting of 22 males and 16 females were included in this study among which 23 patients had Type II axillary contractures and 15 had moderate flexion contractures at elbow joint. The post-operative abduction achieved at shoulder joint had a mean of 168° whereas extension achieved at elbow had a mean of 175°. The functional and aesthetic results were satisfactory. The choice of surgical procedure for reconstruction of post-burn upper extremity contractures should be made according to the pattern of scar contracture and the state of surrounding skin. The choice of subcutaneous pedicle propeller flap should be emphasised because of the superior functional results of flap as well as ease to learn it. Moreover, the modification of propeller flap described achieves better results in terms of scar healing. There is an inter-positioning of healthy skin in between the graft, so it prevents scar band formation all around the flap.

Propeller Flaps With Reduced Rotational Angles: Clinical Experience on 40 Consecutive Reconstructions Performed at Different Anatomical Sites.

PubMed

Brunetti, Beniamino; Tenna, Stefania; Poccia, Igor; Persichetti, Paolo

2017-02-01

Despite of the widespread use of 180-degree propeller flaps in the field of soft tissue reconstruction, less information are available in the current literature to standardize the use of propeller flaps with reduced degrees of rotation.The authors report their experience with propeller flaps with reduced rotational angles reviewing clinical applications and outcomes of the technique in a series of 40 consecutive reconstructions. Forty elective defects of various etiologies located in different regions of the body (head and neck, trunk, buttocks and perineum, extremities) were reconstructed with less than 180 degrees rotated propeller flaps. The technique was applied to patients presenting with a strong audible perforator detected in close proximity to the wound and the defect located in a position adjacent to the axis of the chosen perforasome. Defect size ranged from 2 × 2 to 15 × 9 cm. Flap dimensions ranged from 5 × 2 to 21 × 10 cm. The flaps were based on 1 (34) or 2 (6) perforators and were mobilized with an angle of rotation of 45, 90, and 135 degrees in 7, 24, and 9 patients, respectively. Mean operative time was 105 minutes. All flaps survived postoperatively. In only 4 cases (10%) partial flap necrosis was registered. All flaps achieved adequate and durable reconstruction with excellent contour, with a follow-up ranging between 6 months and 2 years. Propeller flaps with reduced rotational angles represent a safe and versatile option to reconstruct soft tissues defects at different anatomical sites.

Aesthetic Total Reconstruction of Lower Eyelid Using Scapha Cartilage Graft on a Vascularized Propeller Flap.

PubMed

Uemura, Tetsuji; Watanabe, Hidekata; Masumoto, Kazuyuki; Kikuchi, Mamoru; Satake, Yoshiyasu; Yanai, Tetsu; Harada, Yoshimi; Ishihara, Yasuhiro; Yasuta, Masato

2016-04-01

The aim of this study was to review the results of a cohort of patients based on our experience with a new technique for total lower eyelid reconstruction after a large defect caused by malignant tumor and trauma. A scapha cartilage graft with small skin on a vascularized propeller flap was used for 16 cases requiring lower eyelid reconstruction. Patients were identified from a database, and a retrospective case note review was conducted. The scapha cartilage graft was sutured to the margin of the defect of the palpebral conjunctiva and tarsus. The propeller flap, rotated by a perforator-based lateral orbital flap or a subcutaneous-based nasolabial flap, was vascularized on the scapha cartilage graft as anterior lining of the lower eyelid. The follow-up, including results of slit-lamp examination, lasted for varying periods, but often it was for 12 months. The scapha cartilage graft with small skin on a vascularized propeller flap was viable in all cases. Slit-lamp examination detected no irritation or injury of the conjunctiva and cornea, and visual acuity was maintained in all cases. A deformity in the donor helix by this technique was also improved by getting a smaller skin harvested from the scapha. Use of the scapha cartilage graft with small skin on a vascularized propeller flap allows for a good fit to the orbit, short operative time under local anesthesia, good graft viability, and a good esthetic result with minimal donor site morbidity.

Profunda Femoris Artery Perforator Propeller Flap: A Valid Method to Cover Complicated Ischiatic Pressure Sores.

PubMed

Scalise, Alessandro; Tartaglione, Caterina; Bolletta, Elisa; Pierangeli, Marina; Di Benedetto, Giovanni

2015-08-01

We report the case of a 50-year-old paraplegic man with a complicated grade III/IV ischiatic pressure sore treated with a propeller flap based on the first perforator of the profunda femoris artery. Our aim was to surgically reconstruct an ischiatic pressure sore in a patient with ankylosis using a fasciocutaneous perforator propeller flap obtained from the posterior region of the thigh. Our decision to perform a profunda femoris artery perforator propeller flap reconstruction was mainly due to the anatomical contiguity of the flap with the site of the lesion and the good quality of the skin harvested from the posterior region of the thigh. The use of the perforator fasciocutaneous flap represents a muscle-sparing technique, providing a better long-term result in surgical reconstruction. The choice of the 180-degree propeller flap was due to its ability to provide a good repair of the pressure ulcer and to pass over the ischiatic prominence in the patient in the forced decubitus position. The operatory course did not present any kind of complication. Using this reconstructive treatment, we have obtained complete coverage of the ischiatic pressure sore.

Application of multidetector-row computed tomography in propeller flap planning.

PubMed

Ono, Shimpei; Chung, Kevin C; Hayashi, Hiromitsu; Ogawa, Rei; Takami, Yoshihiro; Hyakusoku, Hiko

2011-02-01

The propeller flap is defined as (1) being island-shaped, (2) having an axis that includes the perforators, and (3) having the ability to be rotated around an axis. The advantage of the propeller flap is that it is a pedicle flap that can be applied to cover defects located at the distal ends of the extremities. The specific aims of the authors' study were (1) to evaluate the usefulness of multidetector-row computed tomography in the planning of propeller flaps and (2) to present a clinical case series of propeller flap reconstructions that were planned preoperatively using multidetector-row computed tomography. The authors retrospectively analyzed all cases between April of 2007 and April of 2010 at Nippon Medical School Hospital in Tokyo, where multidetector-row computed tomography was used preoperatively to plan surgical reconstructions using propeller flaps. Thirteen patients underwent 16 flaps using the propeller flap technique. The perforators were identified accurately by multidetector-row computed tomography preoperatively in all cases. This is the first report describing the application of multidetector-row computed tomography in the planning of propeller flaps. Multidetector-row computed tomography is superior to other imaging methods because it demonstrates more precisely the perforator's position and subcutaneous course using high-resolution three-dimensional images. By using multidetector-row computed tomography to preoperatively identify a flap's perforators, the surgeon can better plan the flap design to efficiently conduct the flap surgery.

Propeller thoracodorsal artery perforator flap for breast reconstruction.

PubMed

Angrigiani, Claudio; Rancati, Alberto; Escudero, Ezequiel; Artero, Guillermo; Gercovich, Gustavo; Deza, Ernesto Gil

2014-08-01

The thoracodorsal artery perforator (TDAP) flap has been described for breast reconstruction. This flap requires intramuscular dissection of the pedicle. A modification of the conventional TDAP surgical technique for breast reconstruction is described, utilizing instead a propeller TDAP flap. The authors present their clinical experience with the propeller TDAP flap in breast reconstruction alone or in combination with expanders or permanent implants. From January 2009 to February 2013, sixteen patients had breast reconstruction utilizing a propeller TDAP flap. Retrospective analysis of patient characteristics, clinical indications, procedure and outcomes were performed. The follow-up period ranged from 4 to 48 months. Sixteen patients had breast reconstruction using a TDAP flap with or without simultaneous insertion of an expander or implant. All flaps survived, while two cases required minimal resection due to distal flap necrosis, healing by second intention. There were not donor-site seromas, while minimal wound dehiscence was detected in two cases. The propeller TDAP flap appears to be safe and effective for breast reconstruction, resulting in minimal donor site morbidity. The use of this propeller flap emerges as a true alternative to the traditional TDAP flap.

Fasciocutaneous Propeller Flap Based on Perforating Branch of Ulnar Artery for Soft Tissue Reconstruction of the Hand and Wrist.

PubMed

Jang, Hyo Seok; Lee, Young Ho; Kim, Min Bom; Chung, Joo Young; Seok, Hyun Sik; Baek, Goo Hyun

2018-03-01

A skin defect of the hand and wrist is a common manifestation in industrial crushing injuries, traffic accidents or after excision of tumors. We reconstructed a skin defect in the ulnar aspect of the hand and wrist with a perforator-based propeller flap from the ulnar artery. The aims of our study are to evaluate the utility and effectiveness of this flap and to discuss the advantages and disadvantages of the flap in hand and wrist reconstruction with a review of the literature. Between April 2011 and November 2016, five cases of skin defect were reconstructed with a perforator-based propeller flap from the ulnar artery. There were four males and one female. The age of patients ranged from 36 to 73 years. Skin defect sites were on the dorso-ulnar side of the hand in three cases and palmar-ulnar side of the wrist in two cases. The size of the skin defect ranged from 4 × 3 cm to 8 × 5 cm. We evaluated the viability of the flap, postoperative complication and patient's satisfaction. There was no failure of flap in all cases. The size of the flap ranged from 4 × 4 cm to 12 × 4 cm. One patient, who had a burn scar contracture, presented with limited active and passive motion of the wrist after the operation. The other patients had no complications postoperatively. Cosmetic results of the surgery were excellent in one patient, good in three patients, and fair in one patient. The fasciocutaneous propeller flap based on a perforating branch of the ulnar artery is a reliable treatment option for the ulnar side skin defect of the hand and wrist.

Gastrocnaemius-propeller extended miocutanous flap: a new chimaeric flap for soft tissue reconstruction of the knee.

PubMed

Innocenti, M; Cardin-Langlois, E; Menichini, G; Baldrighi, C

2014-02-01

Soft tissue defects involving the anterior aspect of the knee are a frequent finding in a number of pathological conditions. The aim of this article is to describe a new pedicled flap consisting of a conventional medial gastrocnaemius muscle flap associated with a propeller flap based on a perforator of the medial sural artery. Five males ranging in age between 26 and 72 years underwent a reconstruction of the soft tissue of the knee by means of the described procedure. Three patients sustained complex tissue loss subsequent to high-energy trauma; two losses were due to septic complications after elective knee surgery. Four flaps survived allowing adequate proximal tibial metaphysis and patella coverage. One patient underwent early above-the-knee amputation due to life-threatening septicaemia. The described chimaera flap consists of a medial gastrocnaemius flap with a skin paddle that is elevated on a perforator of the medial sural artery and then rotated according to the propeller flaps' principles. It provides effective coverage of large soft tissue defects of the knee. In the authors' experience, the propeller flap portion proved to be particularly useful to cover the patella, while the muscle flap was used to cover the proximal metaphysis of the tibia and fill the dead space if present. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Propeller flap reconstruction of abdominal defects: review of the literature and case report.

PubMed

Scaglioni, Mario F; Giuseppe, Alberto Di; Chang, Edward I

2015-01-01

The abdominal wall is perfused anteriorly by the superior and deep epigastric vessels with a smaller contribution from the superficial system. The lateral abdominal wall is perfused predominantly from perforators arising from the intercostal vessels. Reconstruction of soft tissue defects involving the abdomen presents a difficult challenge for reconstructive surgeons. Pedicle perforator propeller flaps can be used to reconstruct defects of the abdomen, and here we present a thorough review of the literature as well as a case illustrating the perforasome propeller flap concept. A patient underwent resection for dermatofibrosarcoma protuberans resulting in a large defect of the epigastric soft tissue. A propeller flap was designed based on a perforator arising from the superior deep epigastric vessels and was rotated 90° into the defect allowing primary closure of the donor site. The patient healed uneventfully and was without recurrent disease 37 months following reconstruction. Perforator propeller flaps can be used successfully in reconstruction of abdominal defects and should be incorporated into the armamentarium of reconstructive microsurgeons already facile with perforator dissections. © 2014 Wiley Periodicals, Inc.

Propeller flaps in eyelid reconstruction.

PubMed

Rajak, Saul N; Huilgol, Shyamala C; Murakami, Masahiro; Selva, Dinesh

2018-03-14

Propeller flaps are island flaps that reach the recipient site through an axial rotation. The flap has a subcutaneous pedicle on which it pivots, thereby resembling a helicopter propeller. We present our series of propeller flaps for the reconstruction of large eyelid defects. This is a retrospective review of the clinical case notes of eight patients that underwent tumour excision with reconstruction with a cutaneous propeller flap supplied by a non-perforator orbicularis pedicle between July and December 2016. Propeller flaps were used in the reconstruction of five lower lid defects (size range 19 × 5 mm to 25 × 8 mm), one medial canthus defect (13 mm diameter), one complete upper lid defect (42 × 19 mm diameter) and one lid sparing extenteration defect. The flaps were recruited from nasolabial, lateral canthal, temple or medial upper cheek skin. Post-operatively one case had 'trapdooring' which required flap revision at 4 months and one had persistent oedema that settled without intervention. The reconstruction of large eyelid defects is challenging in part because of the paucity of locally available skin. Propeller flaps are a paradigm shift in periocular reconstruction in which the subcutaneous pedicle enables the recruitment of large and highly mobile skin flaps from a wide area of regional tissue.

Peroneal perforator pedicle propeller flap for lower leg soft tissue defect reconstruction: Clinical applications and treatment of venous congestion

PubMed Central

Liu, Yiyang; Zhang, Chun; Guo, Qiaofeng; Huang, Wenhua; Wong, Kelvin Kian Loong; Chang, Shimin

2017-01-01

Objective To describe the characteristics of the perforator vessel in the peroneal artery of the lower leg and to explore the use of perforator pedicle propeller flaps to repair soft tissue defects in the lower leg, heel and foot. Methods This retrospective study enrolled patients with soft tissue defects of the distal lower leg, heel and foot who underwent surgery using peroneal perforator-based propeller flaps. The peroneal artery perforators were identified preoperatively by colour duplex Doppler ultrasound. The flap was designed based on the preoperatively-identified perforator location, with the posterior border of the fibula employed as an axis, and the perforator vessel as the pivot point of rotation. Patients were followed-up to determine the outcomes. Results The study analysed 36 patients (mean age, 39.7 years). The majority of the soft tissue defects were on the heel (20; 55.6%). The donor-site of the flap was closed in 11 patients by direct suturing and skin grafting was undertaken in 25 patients. Postoperative complications included venous congestion (nine patients), which was managed with delayed wound coverage and bleeding therapy. All wounds were eventually cured and the flaps were cosmetically acceptable. Conclusions The peroneal perforator pedicle propeller flap is an appropriate choice to repair soft tissue defects of the distal limbs. PMID:28345420

Peroneal perforator pedicle propeller flap for lower leg soft tissue defect reconstruction: Clinical applications and treatment of venous congestion.

PubMed

Shen, Lifeng; Liu, Yiyang; Zhang, Chun; Guo, Qiaofeng; Huang, Wenhua; Wong, Kelvin Kian Loong; Chang, Shimin

2017-06-01

Objective To describe the characteristics of the perforator vessel in the peroneal artery of the lower leg and to explore the use of perforator pedicle propeller flaps to repair soft tissue defects in the lower leg, heel and foot. Methods This retrospective study enrolled patients with soft tissue defects of the distal lower leg, heel and foot who underwent surgery using peroneal perforator-based propeller flaps. The peroneal artery perforators were identified preoperatively by colour duplex Doppler ultrasound. The flap was designed based on the preoperatively-identified perforator location, with the posterior border of the fibula employed as an axis, and the perforator vessel as the pivot point of rotation. Patients were followed-up to determine the outcomes. Results The study analysed 36 patients (mean age, 39.7 years). The majority of the soft tissue defects were on the heel (20; 55.6%). The donor-site of the flap was closed in 11 patients by direct suturing and skin grafting was undertaken in 25 patients. Postoperative complications included venous congestion (nine patients), which was managed with delayed wound coverage and bleeding therapy. All wounds were eventually cured and the flaps were cosmetically acceptable. Conclusions The peroneal perforator pedicle propeller flap is an appropriate choice to repair soft tissue defects of the distal limbs.

Anatomical study of the popliteal artery perforator-based propeller flap and its clinical application.

PubMed

Onishi, Tadanobu; Shimizu, Takamasa; Omokawa, Shohei; Sananpanich, Kanit; Kido, Akira; Mahakkanukrauh, Pasuk; Tanaka, Yasuhito

2018-05-30

There is lack of anatomical information regarding cutaneous perforator of the popliteal artery and its connections with the descending branch of the inferior gluteal and profunda femoris arteries. We aimed to evaluate the anatomical basis of popliteal artery perforator-based propeller flap from the posterior thigh region and to demonstrate our experience utilizing this flap. Ten fresh cadaveric lower extremities were dissected following injection of a silicone compound into the femoral artery. We investigated the number, location, length, and diameter of cutaneous perforators of the popliteal artery. Based on the results, we treated three cases with a large soft tissue defect around the knee using popliteal artery perforator-based propeller flap. We found a mean of 1.9 cutaneous perforators arising from the popliteal artery with a mean pedicle length of 6 cm and a mean arterial internal diameter of 0.9 mm, which were located at an average of 4 cm proximal to the bicondylar line. The most distal perforator consistently arose along the small saphenous vein and connected proximally with concomitant artery of the posterior femoral cutaneous nerve, forming a connection with perforating arteries of the profunda femoris artery. A mean of 4.5 cutaneous perforators branched from the arterial connection sites. All clinical cases healed without any complications. The popliteal artery perforator-based propeller flap is reliable for reconstruction of soft tissue defects around the knee. The flap should include the deep fascia and concomitant artery along with the posterior femoral cutaneous nerve for maintaining the blood supply.

Intercostal artery perforator propeller flap for reconstruction of trunk defects following sarcoma resection.

PubMed

Zang, Mengqing; Yu, Shengji; Xu, Libin; Zhao, Zhenguo; Zhu, Shan; Ding, Qiang; Liu, Yuanbo

2015-06-01

Trunk defects following soft tissue sarcoma resection are usually managed by myocutaneous flaps or free flaps. However, harvesting muscle will cause functional morbidities and some trunk regions lack reliable recipient vessels. The intercostal arteries give off multiple perforators, which distribute widely over the trunk and can supply various pedicle flaps. Our purpose is to use various intercostal artery perforator propeller flaps for trunk oncologic reconstruction. Between November 2013 and July 2014, nine intercostal artery perforator propeller flaps were performed in seven patients to reconstruct the defects following sarcoma resection in different regions of the trunk, including the back, lumbar, chest, and abdomen. Two perforators from intercostal arteries were identified for each flap using Doppler ultrasound probe adjacent to the defect. The perforator with visible pulsation was chosen as the pedicle vessel. An elliptical flap was raised and rotated in a propeller fashion to repair the defects. There were one dorsal intercostal artery perforator flap, four dorsolateral intercostal artery perforator flaps, three lateral intercostal artery perforator flaps, and one anterior intercostal artery perforator flap. The mean skin paddle dimension was 9.38 cm in width (range 6-14 cm) and 21.22 cm in length (range 13-28 cm). All intercostal artery perforator flaps survived completely, except for marginal necrosis in one flap harvested close to the previous flap donor site. The intercostal artery perforator propeller flap provides various and valuable options in our reconstructive armamentarium for trunk oncologic reconstruction. To our knowledge, this is the first case series of using intercostal artery perforator propeller flaps for trunk oncologic reconstruction and clinical application of dorsolateral intercostal artery perforator flaps. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Dorsal Intercostal Artery Perforator Propeller Flaps: A Reliable Option in Reconstruction of Large Meningomyelocele Defects.

PubMed

Basterzi, Yavuz; Tenekeci, Goktekin

2016-04-01

Several options have been reported for the reconstruction of myelomeningocele defects. In this article, we present our experience on soft tissue reconstruction of myelomeningocele defects by using island propeller dorsal intercostal artery perforator (DIAP) flaps. Between January 2008 and February 2014, all newborns with large myelomeningocele defects (13 newborns) were reconstructed with island propeller DIAP flaps. All flaps survived completely. In 8 patients out of 13, venous insufficiency was observed which then resolved spontaneously. Flap donor sites were closed primarily. Myelomeningocele defects with a diameter larger than 5 cm require reconstruction with flaps. To mobilize a well-vascularized tissue over the defect without tension in which the suture lines will not overlap over the midline where the dura is repaired and over the meninges is one of the goals of reconstruction for such defects. Perforator propeller flaps enable us to reach those goals. Use of perforator flaps provides 2 important advantages, namely, more predictability and also more freedom in mobilizing flaps toward the defect. This study proves the reliability of DIAP propeller flaps in the reconstruction of myelomeningocele defects.

How wing compliance drives the efficiency of self-propelled flapping flyers.

PubMed

Thiria, Benjamin; Godoy-Diana, Ramiro

2010-07-01

Wing flexibility governs the flying performance of flapping-wing flyers. Here, we use a self-propelled flapping-wing model mounted on a "merry go round" to investigate the effect of wing compliance on the propulsive efficiency of the system. Our measurements show that the elastic nature of the wings can lead not only to a substantial reduction in the consumed power, but also to an increment of the propulsive force. A scaling analysis using a flexible plate model for the wings points out that, for flapping flyers in air, the time-dependent shape of the elastic bending wing is governed by the wing inertia. Based on this prediction, we define the ratio of the inertial forces deforming the wing to the elastic restoring force that limits the deformation as the elastoinertial number N(ei). Our measurements with the self-propelled model confirm that it is the appropriate structural parameter to describe flapping flyers with flexible wings.

Perforator Based Propeller Flaps in Limb Reconstructive Surgery: Clinical Application and Literature Review

PubMed Central

Artiaco, Stefano; Bianchi, Pasquale; Boux, Elena; Tos, Pierluigi

2014-01-01

The reconstruction of loss of substance due to trauma or oncological excision may have relevant functional and aesthetic implications. We report our experience in twenty-one cases of propeller flaps for the treatment of loss of substance of the upper and lower limbs. The etiology of defect was tumor excision in nine cases, trauma in seven cases, surgical wound complications in four cases, and chronic osteomyelitis in one case. Clinical results were favorable in most cases and eighteen flaps survived. We observed an overall complication rate of 33% with four cases of superficial epidermolysis that spontaneously healed and three cases of partial flap loss ranging from 10 to 50% that required surgical revision by means of skin graft (two cases) or ALT free flap (one case). Propeller flap harvesting requires great care and experience, and potential complications may occur even in expert hands. When indicated by the characteristic of the defect, these flaps can be a useful surgical option for the treatment of loss of substance of upper and lower limbs. PMID:25250327

Propeller facial artery perforator flap as first reconstructive option for nasolabial and perinasal complex defects.

PubMed

Ruiz-Moya, A; Lagares-Borrego, A; Infante-Cossío, P

2015-04-01

Facial cutaneous oncological pathology often involves more than one esthetic unit due to their close boundaries. The reconstruction of both the nasolabial and perinasal regions may be especially complex and challenging for the surgeon. Traditionally, these defects have been reconstructed with local random flaps based on the vascularization provided by the superficial musculoaponeurotic system. In this article, we present our experience in the reconstruction of the aforementioned defects using the propeller facial artery perforator (FAP) flap. A propeller FAP flap was performed for reconstruction in 12 patients with nasolabial or perinasal complex defects after tumoral resection between the years 2011 and 2013. The flap was designed parallel to the nasolabial fold in all cases for achieving direct closure and an aesthetically pleasing outcome. In one of the cases, a paramedian forehead flap was performed simultaneously. Nine patients healed uneventfully, with good functional and esthetic outcomes. One of the flaps developed partial necrosis of the distal end, and another developed temporary postoperative venous congestion, lymphedema, and, finally, trapdoor deformity. The latter complication also occurred in one more flap. The propeller FAP flap is reliable and versatile, with few complications, and it is especially useful when reconstructing complex defects that involve the nasolabial and perinasal regions; therefore, it should be considered as one of the first reconstructive options for the described defects. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Pressure Available for Cooling with Cowling Flaps

NASA Technical Reports Server (NTRS)

Stickle, George W; Naiman, Irven; Crigler, John L

1941-01-01

Report presents the results of a full-scale investigation conducted in the NACA 20-foot tunnel to determine the pressure difference available for cooling with cowling flaps. The flaps were applied to an exit slot of smooth contour at 0 degree flap angle. Flap angles of 0 degree, 15 degrees, and 30 degrees were tested. Two propellers were used; propeller c which has conventional round blade shanks and propeller f which has airfoil sections extending closer to the hub. The pressure available for cooling is shown to be a direct function of the thrust disk-loading coefficient of the propeller.

Propeller Flaps: A Literature Review.

PubMed

Sisti, Andrea; D'Aniello, Carlo; Fortezza, Leonardo; Tassinari, Juri; Cuomo, Roberto; Grimaldi, Luca; Nisi, Giuseppe

2016-01-01

Since their introduction in 1991, propeller flaps are increasingly used as a surgical approach to loss of substance. The aim of this study was to evaluate the indications and to verify the outcomes and the complication rates using this reconstructing technique through a literature review. A search on PubMed was performed using "propeller flap", "fasciocutaneous flap", "local flap" or "pedicled flap" as key words. We selected clinical studies using propeller flaps as a reconstructing technique. We found 119 studies from 1991 to 2015. Overall, 1,315 propeller flaps were reported in 1,242 patients. Most frequent indications included loss of substance following tumor excision, repair of trauma-induced injuries, burn scar contractures, pressure sores and chronic infections. Complications were observed in 281/1242 patients (22.6%) occurring more frequently in the lower limbs (31.8%). Partial flap necrosis and venous congestion were the most frequent complications. The complications' rate was significantly higher in infants (<10 years old) and in the older population (>70 years old) but there was not a significant difference between the sexes. Trend of complication rate has not improved during the last years. Propeller flaps showed a great success rate with low morbidity, quick recovery, good aesthetic outcomes and reduced cost. The quality and volume of the transferred soft tissue, the scar orientation and the possibility of direct donor site closure should be considered in order to avoid complications. Indications for propeller flaps are small- or medium-sized defects located in a well-vascularized area with healthy surrounding tissues. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Risk Factor Analysis of Freestyle Propeller Flaps.

PubMed

Paik, Joo Myong; Pyon, Jai-Kyong

2017-01-01

Background  Freestyle propeller flaps have been widely used as a reconstructive option for both trunk and extremities. It offers the advantage of "like-with-like" reconstruction with an adjacent tissue with no dissection to the source vessels. However, there is the risk of vascular complications. In the present study, the authors investigated the incidence of vascular complications and their risk factors following freestyle propeller flap in the trunk and extremities. Methods  The authors conducted a retrospective review of 50 patients who underwent soft tissue reconstruction of the trunk and the extremities with 55 freestyle propeller flaps from 2004 to 2015. Data regarding patient demographics, surgical details, including the arc of rotation, and flap complications were collected from a prospectively maintained database and analyzed. Results  There were 10 flap complications (18.2%), including 7 superficial partial necrosis, 2 full-thickness partial necrosis, and 1 total necrosis from the 55 freestyle propeller flaps harvested. Previous irradiation was a significant risk factor for flap complications and the propeller flap harvested from the extremities showed a significantly higher rate of complications compared with those harvested from the trunk. Complication rates were higher in flaps with the arc of rotation between 150 and 180 degrees with marginal significance compared with flaps with the arc of rotation less than 150 degrees. Conclusions  Freestyle propeller flaps proved to be a valid and reliable option for reconstruction of defects in the trunk, while complication rate was quite high in the extremities. A prudent preoperative evaluation and preparation may be necessary before performing this surgical technique in the extremities. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Reliability of extended dorsal intercostal artery perforator propeller flaps for reconstruction of large myelomeningocele defects.

PubMed

Tenekeci, Goktekin; Basterzi, Yavuz

2017-01-01

Reconstruction of large myelomeningocele defects using extended (elongated beyond the lateral margin of the latissimus dorsi muscle) dorsal intercostal artery perforator (DICAP) propeller flaps is not recommended by previous studies. However, to provide tension-free and successful closure of a defect, the DICAP propeller flaps must sometimes be elongated beyond this margin. Our experience and results in this issue are discussed. In this article, reconstruction of 11 consecutive cases, with large myelomeningocele defects in which standard DICAP propeller flaps were incapable to close the defect, was achieved using extended DICAP propeller flaps between June 2013 and November 2015. At least two reliable perforators of the neighboring intervertebral spaces are included to supply the flap. Intramuscular dissection of perforators is performed to free the perforators from the surrounding muscle and to gain pedicle length as much as possible to prevent twisting and vascular compromise. All the flaps survived completely except for one patient who had superficial skin necrosis on the most distal part of the flap and had severe accompanying systemic disorders and died on postoperative 14th day. In 7 of 11 patients, venous congestion was noted, which resolved spontaneously. No hematoma or seroma formation was observed during the postoperative follow-up period. Dissection of multiple DICAPs supplying flaps enable us to harvest larger DICAP flaps possibly by providing better arterial supply and venous drainage. We use microsurgical instruments and 4.3× loupe magnification for pedicle dissection in this newborn population. This study shows the reliability of extended DICAP propeller flaps when multiple perforators at sixth or more cranial adjacent intercostal spaces are included in DICAP propeller flaps. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Central artery perforator propeller flap for nasal and medial canthal defects.

PubMed

Baltu, Yahya; Uzun, Hakan; Dölen, Utku Can; Özyurtlu, Mustafa

2016-08-01

Non-melanoma skin cancer is the most common type of skin cancer of the nasal dorsum and the medial canthal region, which is caused by chronic sun exposure. Limited adjacent tissue and the need for aesthetically pleasing result make the reconstruction of these regions very challenging. To overcome this challenge, we designed a perforator propeller flap based on the central artery. Between January 2014 and November 2015, we covered the nasal or medial canthal defects of 22 patients with central artery perforator propeller flaps. The mean age of the patients was 60.4 years (range: 47-81 years). The median follow-up period was 7.5 months (range: 2-23 months). The pathological diagnoses were basal cell carcinoma for 14 patients and squamous cell carcinoma for the remaining eight patients. The size of the defects ranged from 2 × 2 to 3.5 × 4 cm, and that of the flaps ranged from 2 × 3.5 to 3.2 × 6 cm. We did not observe any major complications requiring surgery, such as total flap loss, hematoma, or dog-ear deformity. However, venous congestion was seen in five patients and partial flap necrosis (that healed without intervention) in two patients. The central artery perforator propeller flap is a reliable and versatile flap for the reconstruction of the nasal dorsum and medial canthal region. Reconstruction with this flap is a single-stage procedure that can cover large defects without causing dog-ear deformity or eyebrow asymmetry compared with other local flap options. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

The perforator pedicled propeller (PPP) flap method: report of two cases.

PubMed

Hyakusoku, Hiko; Ogawa, Rei; Oki, Koichiro; Ishii, Nobuaki

2007-10-01

Perforator flaps are thin free-tissue transfers consisting of skin and subcutaneous tissue which have the advantage of decreasing donor site morbidity. We have reconstructed postburn scar contractures using "propeller flaps" of the remaining healthy skin around the recipient sites. In this paper, we report on two cases and describe the concept of using "perforator flaps" and "propeller flaps" together as what are called "perforator pedicled propeller (PPP) flaps." Patient 1 was an 18-year-old man with a sacral pressure ulcer. The soft tissue defect was reconstructed with a rotated superior gluteal artery PPP flap. Patient 2 was a 53-year-old woman who presented with an open fracture of the right elbow. The skin defect over the fracture was covered with a rotated deep brachial artery PPP flap raised on the lateral upper arm. The PPP flaps are useful for burn reconstruction and repairing various types of wound. Moreover, microsurgery is unnecessary. The PPP flap may be classified into two types: the central axis type and the acentric axis type. The central axis PPP flap is significant when used as a 90-degree-rotation island flap, and the acentric axis PPP flap is significant when used as a 180-degree-rotation island flap. Both types are easy to harvest and useful for repairing various kinds of wound.

Design and simulation on the morphing composite propeller (Conference Presentation)

NASA Astrophysics Data System (ADS)

Chen, Fanlong; Li, Qinyu; Liu, Liwu; Lan, Xin; Liu, Yanju; Leng, Jinsong

2017-04-01

As one of the most crucial part of the unmanned underwater vehicle (UUV), the composite propeller plays an important role on the UUV's performance. As the composite propeller behaves excellent properties in hydroelastic facet and acoustic suppression, it attracts increasing attentions all over the globe. This paper goes a step further based on this idea, and comes up with a novel concept of "morphing composite propeller" (MCP) to improve the performance of the conventional composite propeller (CCP) to anticipate the improved propeller can perform better to propel the UUV. Based on the new concept, a novel MCP is designed. Each blade of the propeller is assembled with an active rotatable flap (ARF) to change the blade's local camber with flap rotation. Then the transmission mechanism (TM) has been designed and housed in the propeller blade to push the ARF. With the ARF rotating, the UUV can be propelled by different thrusts under certain rotation velocities of the propeller. Based on the design, the Fluent is exploited to analyze the fluid dynamics around the propeller. Finally, based on the design and hydrodynamic analysis, the structural response for the novel morphing composite propeller is calculated. The propeller blade is simplified and layered with composite materials. And the structure response of an MCP is obtained with various rotation angle under the hydrodynamic pressure. This simulation can instruct the design and fabrication techniques of the MCP.

A new mucosal propeller flap (deep lingual artery axial propeller): the renaissance of lingual flaps.

PubMed

Cordova, Adriana; Toia, Francesca; D'Arpa, Salvatore; Giunta, Gabriele; Moschella, Francesco

2015-03-01

Lingual flaps provide ideal mucosal coverage for intraoral defects but traditionally require two surgical stages. The authors present an axial mucosal propeller flap for single-stage intraoral reconstruction. The flap includes the mucosa of the lateral side of the tongue, islanded on the deep lingual vessels. Between 2011 and 2013, 23 patients underwent intraoral mucosal reconstruction with a deep lingual artery axial propeller flap after cancer resection in the cheek (n = 16), floor of the mouth (n = 2), retromolar trigone (n = 2), hard palate (n = 2), and soft palate (n = 1). Mean defect size was 19.5 cm. Preoperative and postoperative intraoral function was evaluated with the Functional Intraoral Glasgow Scale. The authors always achieved one-stage reconstruction with primary donor-site closure. The only complications were an infection treated conservatively and a late oronasal fistula caused by radiotherapy. All patients resumed an oral diet after 1 week and none required surgical revision. Mean 12-month postoperative Functional Intraoral Glasgow Scale score was better than the preoperative score (13.5 versus 12.8). The deep lingual artery axial propeller flap combines the advantages of the traditional lingual flap (i.e., reliable axial vascularization and like-with-like reconstruction) with those of a propeller flap (i.e., one-stage transfer of like tissue and extreme mobility) and has wider indications than a conventional lingual flap. The technique is fast and has low morbidity and good functional results, and the authors recommend it as a first-choice technique to reconstruct moderate to large intraoral defects. Therapeutic, IV.

TDAP: Island versus propeller.

PubMed

Angrigiani, Claudio; Rancati, Alberto; Artero, Guillermo; Escudero, Ezequiel; Khouri, Roger K

2016-04-01

Thoracodorsal artery perforator (TDAP) island flap is a safe and reliable method for breast reconstruction. TDAP propeller flap has been described as a modification of the conventional island technique that saves time and does not require microsurgical skills. However, a substantial portion of the propeller flap remains under the axilla and is not used for breast augmentation. The aim of this study is to identify the differences in the reaching distances between the propeller and island TDAP flaps. In five cadaveric specimens and 10 breast reconstruction patients, an initial propeller flap was harvested and rotated to the anterior thorax; the distance from the tip of the flap to the anterior midline was recorded as the "midline-reaching deficit;" the flap was then converted into a conventional island flap, and the new midline-reaching deficit was recorded. Differences between groups were compared with paired two-tailed t-tests (α = 0.05). In the cadaveric specimens, the mean midline-reaching deficit was 4.8 ± 2.4 cm with the propeller TDAP and -0.6 ± 2.0 cm with the conventional island TDAP (P < 0.001). In the clinical cases, the mean midline-reaching deficit was 8.1 ± 1.0 cm with the propeller TDAP and -0.3 ± 1.1 cm with the island TDAP (P < 0.000000001). We observed that the midline-reaching deficit could be reduced by 7-9 cm with the conventional island TDAP in comparison to the propeller TDAP. This should be considered when reconstructing the medial inner part of the breast. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Indications, Outcomes, and Complications of Pedicled Propeller Perforator Flaps for Upper Body Defects: A Systematic Review

PubMed Central

Lazzeri, Davide; Huemer, Georg M.; Nicoli, Fabio; Larcher, Lorenz; Dashti, Talal; Grassetti, Luca; Li, Qingfeng; Spinelli, Giuseppe; Agostini, Tommaso

2013-01-01

Background The aim of this investigation was to systematically review the current literature to provide the best data for indications, outcomes, survival, and complication rates of pedicled propeller perforator flaps for upper body defects. Methods A comprehensive literature review for articles published from January 1991 to December 2011 was performed using the PubMed, Medline, and Cochrane Databases. Articles without available full-text, single case reports or papers with excessive missing data were excluded. Papers reporting pedicle-perforator (propeller) flaps used for lower extremity reconstruction were excluded from meta-analysis. Results From the initial 1,736 studies our search yielded, 343 studies qualified for the second stage of selection. Of 117 full-text reports screened, 41 studies, met the definitive inclusion and exclusion criteria. Of the selected 41 articles, 26 were case series, original papers or retrospective reviews and were included, whereas 15 were case report papers and therefore were excluded. Two hundred ninety-five propeller flaps were reported to have been used in a total of 283 patients. Indications include repair of trauma-induced injuries, post-trauma revision surgery, cancer resection, chronic infection, pressure sores, and chronic ulcers with a major complication rate (3.3%) comparable to that of free flaps. No specific exclusion criteria for the procedure were presented in the studies reviewed. Conclusions Pedicled propeller flaps are a versatile and safe reconstructive option that are easy and quick to raise and that provide unlimited clinical solutions because of the theoretical possibility of harvesting them based on any perforator chosen among those classified in the body. PMID:23362479

Comparison of Dorsal Intercostal Artery Perforator Propeller Flaps and Bilateral Rotation Flaps in Reconstruction of Myelomeningocele Defects.

PubMed

Tenekeci, Goktekin; Basterzi, Yavuz; Unal, Sakir; Sari, Alper; Demir, Yavuz; Bagdatoglu, Celal; Tasdelen, Bahar

2018-04-09

Bilateral rotation flaps are considered the workhorse flaps in reconstruction of myelomeningocele defects. Since the introduction of perforator flaps in the field of reconstructive surgery, perforator flaps have been used increasingly in the reconstruction of various soft tissue defects all over the body because of their appreciated advantages. The aim of this study was to compare the complications and surgical outcomes between bilateral rotation flaps and dorsal intercostal artery perforator (DICAP) flaps in the soft tissue reconstruction of myelomeningocele defects. Between January 2005-February 2017, we studied 47 patients who underwent reconstruction of myelomeningocele defects. Patient demographics, operative data, and postoperative data were reviewed retrospectively and are included in the study. We found no statistically significant differences in patient demographics and surgical complications between these two groups; this may be due to small sample size. With regard to complications-partial flap necrosis, cerebrospinal fluid (CSF) leakage, necessity for reoperation, and wound infection-DICAP propeller flaps were clinically superior to rotation flaps. Partial flap necrosis was associated with CSF leakage and wound infection, and CSF leakage was associated with wound dehiscence. Although surgical outcomes obtained with DICAP propeller flaps were clinically superior to those obtained with rotation flaps, there was no statistically significant difference between the two patient groups. A well-designed comparative study with adequate sample size is needed. Nonetheless, we suggest using DICAP propeller flaps for reconstruction of large myelomeningocele defects.

Plantar flaps based on perforators of the plantar metatarsal/common digital arteries.

PubMed

Valentin, Georgescu Alexandru; Rodica, Matei Ileana; Manuel, Llusa

2014-09-01

Because of the unique characteristics of its integument, the affirmation "replacing like with like" becomes more than evident in the reconstruction of defects of the ultraspecialized plantar skin. But, the paucity of local resources, and especially in the forefoot, transforms this attempt in a very challenging problem. Many techniques, including skin grafts and various types of flaps were used in the management of defects in the forefoot. We present a new useful flap in the reconstruction of skin defects in the forefoot, based on small perforator vessels originating either from the plantar metatarsal arteries or plantar common digital arteries. Starting with June 2011, this flap was performed, as plantar transposition perforator flap, plantar propeller flap, or plantar propeller perforator plus flap, in seven patients with ulcers over the plantar forefoot. During a follow-up of 7 to 17 months (mean, 9.8 months), the local evolution regarding flap integration, pain, relapse, sensitive recovery, donor site, and footwear quality was analyzed. We registered a 100% survival rate of the flaps, with delayed healing in only one case. The gait resumption was possible after 6 weeks in all cases. This new flap, based on small perforator vessels from the plantar metatarsal or common digital arteries, and which provides a good, stable, and sensory recovery, seems to be a promising method in the reconstruction of plantar skin defects over the metatarsal heads. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Large-Scale Wind-Tunnel Tests of an Airplane Model with an Unswept, Aspect-Ratio-10 Wing, Two Propellers, and Blowing Flaps

NASA Technical Reports Server (NTRS)

Griffin, Roy N., Jr.; Holzhauser, Curt A.; Weiberg, James A.

1958-01-01

An investigation was made to determine the lifting effectiveness and flow requirements of blowing over the trailing-edge flaps and ailerons on a large-scale model of a twin-engine, propeller-driven airplane having a high-aspect-ratio, thick, straight wing. With sufficient blowing jet momentum to prevent flow separation on the flap, the lift increment increased for flap deflections up to 80 deg (the maximum tested). This lift increment also increased with increasing propeller thrust coefficient. The blowing jet momentum coefficient required for attached flow on the flaps was not significantly affected by thrust coefficient, angle of attack, or blowing nozzle height.

Freestyle multiple propeller flap reconstruction (jigsaw puzzle approach) for complicated back defects.

PubMed

Park, Sung Woo; Oh, Tae Suk; Eom, Jin Sup; Sun, Yoon Chi; Suh, Hyun Suk; Hong, Joon Pio

2015-05-01

The reconstruction of the posterior trunk remains to be a challenge as defects can be extensive, with deep dead space, and fixation devices exposed. Our goal was to achieve a tension-free closure for complex defects on the posterior trunk. From August 2006 to May 2013, 18 cases were reconstructed with multiple flaps combining perforator(s) and local skin flaps. The reconstructions were performed using freestyle approach. Starting with propeller flap(s) in single or multilobed design and sequentially in conjunction with adjacent random pattern flaps such as fitting puzzle. All defects achieved tensionless primary closure. The final appearance resembled a jigsaw puzzle-like appearance. The average size of defect was 139.6 cm(2) (range, 36-345 cm(2)). A total of 26 perforator flaps were used in addition to 19 random pattern flaps for 18 cases. In all cases, a single perforator was used for each propeller flap. The defect and the donor site all achieved tension-free closure. The reconstruction was 100% successful without flap loss. One case of late infection was noted at 12 months after surgery. Using multiple lobe designed propeller flaps in conjunction with random pattern flaps in a freestyle approach, resembling putting a jigsaw puzzle together, we can achieve a tension-free closure by distributing the tension to multiple flaps, supplying sufficient volume to obliterate dead space, and have reliable vascularity as the flaps do not need to be oversized. This can be a viable approach to reconstruct extensive defects on the posterior trunk. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Aesthetic Penoscrotal Resurfacing: Creating Propeller Flaps from Gluteal Folds.

PubMed

Han, So-Eun; Kim, Eun-Ji; Sung, Hyun Hwan; Pyon, Jai-Kyong

2018-04-01

Reconstruction of extensive penoscrotal defects is a surgical challenge. Resurfacing defects in highly complex three-dimensional structures and restoring their function are an essential part of the reconstruction of penoscrotal regions. We describe a technique using internal pudendal artery perforator (IPAP) pedicled propeller flaps created from the gluteal fold. This could be a reliable surgical option that maintains a natural looking scrotal pouch with minimal donor site morbidity and optimal sexual activity. We retrospectively reviewed data for 10 consecutive patients who had undergone penoscrotal reconstruction using IPAP pedicled propeller flaps between January 2011 and March 2015. The IPAP was identified using a hand-held Doppler ultrasound device. This was the pivot around which the flap was internally rotated more than 90° in a tension-free manner. The long axis of the flap was centred on the gluteal fold to provide a better-orientated donor site scar. Complications and patient satisfaction with respect to size, colour match, scar appearance, and sexual activity were evaluated. Anatomic and aesthetic penoscrotal reconstruction was performed without any major complications in the follow-up period (mean, 19.7 mo). The mean width of the IPAP pedicled propeller flaps was 6.7cm, and the mean length was 11.7cm. Partial distal flap necrosis occurred in only one case, and healed spontaneously. All of the patients were satisfied with the cosmetic and functional results. On the basis of reliable perforators, donor site morbidity, flap thickness, and a better orientated scar, our technique using IPAP pedicled propeller flaps created from the gluteal fold could be a reasonable surgical option for extensive penoscrotal reconstruction. The creation of pedicled propeller flaps using an internal pudendal artery perforator could be a reliable surgical option for reconstruction of extensive penoscrotal defects. The approach yields functional and aesthetically acceptable surgical results. Copyright © 2016. Published by Elsevier B.V.

Posterior trunk reconstruction with the dorsal intercostal artery perforator based flap: Clinical experience on 20 consecutive oncological cases.

PubMed

Brunetti, Beniamino; Tenna, Stefania; Aveta, Achille; Poccia, Igor; Segreto, Francesco; Cerbone, Vincenzo; Persichetti, Paolo

2016-10-01

Few studies in the recent literature have investigated the reliability of dorsal intercostal artery perforator (DICAP) flap in posterior trunk reconstruction. The purpose of this report is to describe our clinical experience with the use of DICAP flaps in a cohort of oncological patients. Twenty patients underwent posterior trunk reconstruction with DICAP based flaps. Patients age ranged from 45 to 76 years. All defects resulted from skin cancer ablation. Defect sizes ranged from 4 × 4 to 6 × 8 cm. The flaps were mobilized in V-Y or propeller fashion. The flaps were islanded on 1 (12 cases), 2 (6 cases), or 3 (2 cases) perforators. Donor sites were always closed primarily. Eleven V-Y advancement flaps were performed; one of these was converted to a perforator-plus peninsular flap design, which retained an additional source of blood supply from the opposite skin bridge. Nine flaps were mobilized in propeller fashion. Flap dimensions ranged from 4 × 6 to 6 × 14 cm. Mean operative time was 70 min. One V-Y flap complicated with marginal necrosis that healed with no need for reintervention. All the other flaps survived uneventfully. No other complications were observed at recipient and donor sites. Follow-up ranged from 3 months to 2 years. All the patients were satisfied with the surgical outcome. DICAP based flaps proved to be a reliable option to resurface posterior trunk defects following oncological resection, allowing to achieve like-with-like reconstruction with excellent contour and minimal donor-site morbidity. © 2015 Wiley Periodicals, Inc. Microsurgery 36:546-551, 2016. © 2015 Wiley Periodicals, Inc.

A Systematic Review and Meta-Analysis of Perforator-Pedicled Propeller Flaps in Lower Extremity Defects: Identification of Risk Factors for Complications.

PubMed

Bekara, Farid; Herlin, Christian; Mojallal, Ali; Sinna, Raphael; Ayestaray, Benoit; Letois, Flavie; Chavoin, Jean Pierre; Garrido, Ignacio; Grolleau, Jean Louis; Chaput, Benoit

2016-01-01

Currently, increased interest in the perforator-pedicled propeller flap should not obscure the fact that it is, in reality, a complex procedure requiring experience and monitoring similar to free flaps. Through a meta-analysis, the authors aimed to identify the risk factors of perforator-pedicled propeller flap failure in lower extremity defects. The MEDLINE, PubMed Central, Embase, and Cochrane databases were searched from 1991 to May of 2014 for articles describing perforator-pedicled propeller flaps in the lower extremity. The study selection met the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Fixed-effects models were used. Forty articles complied with the inclusion criteria, representing 428 perforator-pedicled propeller flaps. The most common cause was posttraumatic (55.2 percent). Most of the defects were at the distal third of the lower leg (45.6 percent). The arc of rotation was 180 degrees for 34.3 percent. Complications were found in 25.2 percent, including partial necrosis (10.2 percent) and complete necrosis (3.5 percent). Complete flap survival was found in 84.3 percent. The authors identified three significant risk factors: age older than 60 years (relative risk, 1.61; p = 0.03), diabetes (relative risk, 2.00; p = 0.02), and arteriopathy (relative risk, 3.12; p = 0.01). No significant results were found regarding smoking status other than a tendency (p = 0.06), acute cause (p = 0.59), posttraumatic cause (p = 0.97), distal third of the lower leg (p = 0.66), fascia inclusion (p = 0.70), and pedicle rotation greater than 120 degrees (p = 0.41). Age older than 60 years, diabetes, and arteriopathy are significant risk factors of perforator-pedicled propeller flap complications in the lower extremity. Risk, IV.

Investigation of the Effectiveness of Boundary-layer Control by Blowing over a Combination of Sliding and Plain Flaps in Deflecting a Propeller Slipstream Downward for Vertical Take-off

NASA Technical Reports Server (NTRS)

Spreemann, Kenneth P; Kuhn, Richard E

1956-01-01

An investigation was conducted in order to determine the effectiveness of blowing a jet of air over the flaps of a wing equipped with a 50-percent-chord sliding flap and a 25-percent-chord plain flap in deflecting a propeller slipstream downward for vertical take-off and the results are presented herein. The effects of a leading-edge slat, ground proximity, end plate, and propeller position were also investigated. The tests were conducted in a static-thrust facility at the Langley Aeronautical Laboratory.

Propeller Flaps and Its Outcomes - A Prospective Study of 15 Cases Over Two-years.

PubMed

K T, Ramesha; J, Vijay; M, Shankarappa

2014-01-01

Cover flaps are needed in management of any bodily defect involving bone, tendon, nerve & vessels. The major objective of a plastic surgeon, facing a complex soft-tissue defect, is to replace "like with like" tissues at minimal donor site "cost" and with maximal accuracy & efficacy. To study the "Propeller Flaps" utility in reconstructive surgeries, evaluate its planning and complications involving donor site morbidity. The prospective study was conducted on 15 cases (11 males/4 females) of propeller flaps during the period of two years (2010-12) in Department of Plastic Surgery and Burns, Bangalore Medical College and Research Institute (BMCRI), Karnataka, India. The propeller flaps were performed in cases with defects due to any cause. Cases with Peripheral Vascular Disease (PVD). Flaps were performed and details recorded. Overall results revealed problem resolution in 87% cases (13 cases). Comprehensive description of each flap type and its related cases are given in the table. It has been categorically found that there were 2 flap partial losses. Partial necrosis has been reported in heavy-smoker patients. This current study clearly justifies that careful application, optimal designing & judicious scientific application of local perforator flaps for lower-limb wounds including rest of the body is successful in many aspects providing high-quality reconstruction ensuring minimal morbidity. It is cost-effective as well as time-saving.

Ad hoc posterior tibial vessels perforator propeller flaps for the reconstruction of lower third leg soft- tissue defects.

PubMed

Balakrishnan, Thalaivirithan Margabandu; Ramkumar, Jayagosh; Jaganmohan, Janardhanan

2017-01-01

Lower third leg soft tissue defects with anatomical and pathological constraints are posing formidable challenges to reconstructive surgeon. This retrospective study was conducted to assess the effectiveness of ad hoc posterior tibial vessels perforator-propeller flaps for the reconstruction of small and medium sized soft tissue defects in the lower third leg. 22 patients (16 were males and 6 were females) were involved in this study between period of January 2012 and December 2016.We followed the protocol of initial non delineating exploratory incision made to find out single best perforator in all patients. All the defects in leg reconstructed with adhoc posterior tibial vessel propeller flaps. All 22 flaps survived well. All in an average of 13 months follow up period, had pain free walking, with minimal scarring and acceptable aesthesis at the reconstruction sites with no need for any secondary procedure. With inability of preoperatively dopplering the perforators in the lower third leg region, the exploratory posterior nondelineating incision was used in all cases to secure the single best perforator for the propeller flaps. Thus adhoc posterior tibial vessel propeller flaps are dependable, easily adoptable for the reconstruction of soft tissue defects of the lower third leg region.

Ad hoc posterior tibial vessels perforator propeller flaps for the reconstruction of lower third leg soft- tissue defects

PubMed Central

Balakrishnan, Thalaivirithan Margabandu; Ramkumar, Jayagosh; Jaganmohan, Janardhanan

2017-01-01

Introduction: Lower third leg soft tissue defects with anatomical and pathological constraints are posing formidable challenges to reconstructive surgeon. Aim: This retrospective study was conducted to assess the effectiveness of ad hoc posterior tibial vessels perforator-propeller flaps for the reconstruction of small and medium sized soft tissue defects in the lower third leg. Patients and Methods: 22 patients (16 were males and 6 were females) were involved in this study between period of January 2012 and December 2016.We followed the protocol of initial non delineating exploratory incision made to find out single best perforator in all patients. All the defects in leg reconstructed with adhoc posterior tibial vessel propeller flaps. Results: All 22 flaps survived well. All in an average of 13 months follow up period, had pain free walking, with minimal scarring and acceptable aesthesis at the reconstruction sites with no need for any secondary procedure. Conclusion: With inability of preoperatively dopplering the perforators in the lower third leg region, the exploratory posterior nondelineating incision was used in all cases to secure the single best perforator for the propeller flaps. Thus adhoc posterior tibial vessel propeller flaps are dependable, easily adoptable for the reconstruction of soft tissue defects of the lower third leg region. PMID:29618863

STOL Characteristics of a Propeller-Driven, Aspect-Ratio-10, Straight-Wing Airplane with Boundary-Layer Control Flaps, as Estimated from Large-Scale Wind-Tunnel Tests

NASA Technical Reports Server (NTRS)

Weiberg, James A; Holzhauser, Curt A.

1961-01-01

A study is presented of the improvements in take-off and landing distances possible with a conventional propeller-driven transport-type airplane when the available lift is increased by propeller slipstream effects and by very effective trailing-edge flaps and ailerons. This study is based on wind-tunnel tests of a 45-foot span, powered model, with BLC on the trailing-edge flaps and controls. The data were applied to an assumed airplane with four propellers and a wing loading of 50 pounds per square foot. Also included is an examination of the stability and control problems that may result in the landing and take-off speed range of such a vehicle. The results indicated that the landing and take-off distances could be more than halved by the use of highly effective flaps in combination with large amounts of engine power to augment lift (STOL). At the lowest speeds considered (about 50 knots), adequate longitudinal stability was obtained but the lateral and directional stability were unsatisfactory. At these low speeds, the conventional aerodynamic control surfaces may not be able to cope with the forces and moments produced by symmetric, as well as asymmetric, engine operation. This problem was alleviated by BLC applied to the control surfaces.

[Propeller facial artery perforator flap for repairing defect after resection of skin malignant tumor at upper lip].

PubMed

Yao, Yuanzhen; Tang, Xiujun; Wang, Dali; Wei, Zairong; Wang, Bo; Deng, Chengliang; Zhang, Ziyang; Jin, Wenhu

2018-02-01

To explore the effectiveness of propeller facial artery perforator flap to repair the defect after resection of skin malignant tumor at upper lip. Between July 2012 and January 2017, 17 cases with skin malignant tumor at upper lip underwent tumor resection and the remained defect was repaired with propeller facial artery perforator flap. Among the 17 patients, 3 were male and 14 were female, with an average age of 57 years (range, 35-82 years). There were 5 cases of squamous cell carcinoma and 12 cases of basal cell carcinoma. The disease duration ranged from 4 months to 11 years with an average of 20 months. The tumor size ranged from 1.4 cm×0.3 cm to 3.1 cm×1.4 cm. The extended resection of the tumor tissue was performed according to the characters of tumor. According to the location, size, and shape of the defect and the position of facial artery perforator explored with Doppler ultrasonography, the propeller facial artery perforator flap was designed to repair the defect and partial donor site. The flap size ranged from 5 cm×2 cm to 7 cm×3 cm. The length of the perforator pedicle was 0.5-1.0 cm with an average of 0.8 cm. The defect at donor site was directly closed. Cyanosis occurred in 3 cases of the distal flap after operation, then healing after symptomatic treatment. The remaining flaps survived successfully and the wound healed by first intention. Primary healing was obtained in the donor site. All the patients were followed up 6-36 months with an average of 18 months. The shape of the patient's upper lip was good and the scar on the donor site was unconspicuous. There was no lip deformity, ala nasi deflection, facial tension, entilation dysfunction, or recurrence of tumor during follow-up. At last follow-up, the results of self-evaluation were very satisfactory in 13 cases and satisfactory in 4 cases. Based on multiple advantages of good blood supply, large rotation range, aesthetic outcome, and slight injury of the donor site, propeller facial artery perforator flap is not only an optimal choice for repairing upper lip defect after resection of skin malignant tumors, but also can achieve good functional and cosmetic effectiveness.

Bilateral Breast Reconstruction with Extended Thoracodorsal Artery Perforator Propeller Flaps and Implants

PubMed Central

Gunnarsson, Gudjon L.; Børsen-Koch, Mikkel; Nielsen, Henrik T.; Salzberg, Andrew

2015-01-01

Summary: We present our experience of bilateral total breast reconstruction using a double-sided extended thoracodorsal artery perforator propeller flap in a case series of 10 patients. Reconstruction was successfully achieved in all cases with few complications. The median time for surgery was 275 minutes (200–330), and the average implant size used was 350 cm3 (195–650). We demonstrate how the extended thoracodorsal artery perforator propeller flap allows for a swift and reliable direct to implant bilateral total breast reconstruction in a simple setting and is a valuable adjunct to our armamentarium of techniques for single-stage bilateral breast reconstruction. PMID:26180736

Single perforator greater saphenous neuro-veno-fasciocutaneous propeller flaps for lower extremity reconstructions.

PubMed

Zhong, Wanrun; Lu, Shengdi; Wang, Chunyang; Wen, Gen; Han, Pei; Chai, Yimin

2017-07-01

The lack of soft tissue that is available for medial leg and foot defect reconstructions presents a challenge for plastic surgeons. The saphenous neurofasciocutaneous perforator flap application presents an effective alternative to local flap transfers. However, the venous flow and pedicle twisting problems are still disputed. Here, we present our experiences with modified cutaneous pedicles with a single perforator pedicle, which improves the venous flow and the pedicle twisting problem. This study was conducted from June 2007 through September 2011, and a total of 15 patients with lower medial leg and foot defects were included. There were 11 men and four women. An asymmetric 'propeller' flap was planned around a perforator that was adjacent to the defects, which was preoperatively confirmed by Doppler. The perforator was sufficiently dissociated to allow for the flap to be turned towards the defects. We preserved some distal skin and subcutaneous tissue from the short side of the 'propeller' to cover some donor site regions, and other regions were covered with split thickness skin grafts. The follow-up period ranged from 3 to 12 months. An infection occurred in one case. Partial flap necrosis was noted in two cases. The other 12 flaps completely survived and matched the recipient sites with regard to colour, texture and thickness. The single perforator greater saphenous neuro-veno-fasciocutaneous propeller flap is an effective solution for medial leg and foot defects, and it has a large rotation arc and a satisfactory aesthetic result. © 2015 Royal Australasian College of Surgeons.

Prediction of the effects of propeller operation on the static longitudinal stability of single-engine tractor monoplanes with flaps retracted

NASA Technical Reports Server (NTRS)

Weil, Joseph; Sleeman, William C , Jr

1949-01-01

The effects of propeller operation on the static longitudinal stability of single-engine tractor monoplanes are analyzed, and a simple method is presented for computing power-on pitching-moment curves for flap-retracted flight conditions. The methods evolved are based on the results of powered-model wind-tunnel investigations of 28 model configurations. Correlation curves are presented from which the effects of power on the downwash over the tail and the stabilizer effectiveness can be rapidly predicted. The procedures developed enable prediction of power-on longitudinal stability characteristics that are generally in very good agreement with experiment.

Propeller Perforator Flaps in Distal Lower Leg: Evolution and Clinical Applications

PubMed Central

2012-01-01

Simple or complex defects in the lower leg, and especially in its distal third, continue to be a challenging task for reconstructive surgeons. A variety of flaps were used in the attempt to achieve excellence in form and function. After a long evolution of the reconstructive methods, including random pattern flaps, axial pattern flaps, musculocutaneous flaps and fasciocutaneous flaps, the reappraisal of the works of Manchot and Salmon by Taylor and Palmer opened the era of perforator flaps. This era began in 1989, when Koshima and Soeda, and separately Kroll and Rosenfield described the first applications of such flaps. Perforator flaps, whether free or pedicled, gained a high popularity due to their main advantages: decreasing donor-site morbidity and improving aesthetic outcome. The use as local perforator flaps in lower leg was possible due to a better understanding of the cutaneous circulation, leg vascular anatomy, angiosome and perforasome concepts, as well as innovations in flaps design. This review will describe the evolution, anatomy, flap design, and technique of the main distally pedicled propeller perforator flaps used in the reconstruction of defects in the distal third of the lower leg and foot. PMID:22783507

Thrust augmentation in tandem flapping foils by foil-wake interaction

NASA Astrophysics Data System (ADS)

Anderson, Erik; Lauder, George

2006-11-01

Propulsion by pitching and heaving airfoils and hydrofoils has been a focus of much research in the field of biologically inspired propulsion. Organisms that use this sort of propulsion are self-propelled, so it is difficult to use standard experimental metrics such as thrust and drag to characterize performance. We have constructed a flapping foil robot mounted in a flume on air-bearings that allows for the determination of self-propelled speed as a metric of performance. We have used a pair of these robots to examine the impact of an upstream flapping foil on a downstream flapping foil as might apply to tandem fins of a swimming organism or in-line swimming of schooling organisms. Self-propelled speed and a force transducer confirmed significant thrust augmentation for particular foil-to-foil spacings, phase differences, and flapping frequencies. Flow visualization shows the mechanism to be related to the effective angle of attack of the downstream foil due to the structure of the wake of the upstream foil. This confirms recent computational work and the hypotheses by early investigators of fish fluid dynamics.

Investigation of Effectiveness of a Wing Equipped with a 50-percent-chord Sliding Flap, a 30-percent-chord Slotted Flap, and a 30-percent-chord Slat in Deflecting Propeller Slipstreams Downward for Vertical Take-off

NASA Technical Reports Server (NTRS)

Kuhn, Richard E

1957-01-01

Results are presented of an investigation of the effectiveness of a wing equipped with a 50-percent-chord sliding flap and a 30-percent-chord slotted flap in deflecting a propeller slipstream downward for vertical take-off. Tests were conducted at zero forward speed in a large room and included the effects of flap deflection, proximity to the ground, a leading-edge slat, and end plates. A turning angle of about 70 degrees and a resultant force of about 100 percent of the thrust were achieved near the ground. Out of the ground-effect region, the turning angle was also about 70 degrees but the resultant force was reduced to about 86 percent of the thrust.

[CLINICAL APPLICATION AND EXPERIENCE IN RECONSTRUCTION OF SOFT TISSUE DEFECTS FOLLOWING MALIGNANT TUMOR REMOVAL OF LIMBS USING PERFORATOR PROPELLER FLAPS].

PubMed

Zhu, Shan; Liu, Yuanbo; Yu, Shengji; Zang, Mengqing; Zhao, Zhenguo; Xu, Libin; Zhang, Xinxin; Chen, Bo; Ding, Qiang

2016-01-01

To explore the feasibility and technical essentials of soft tissue defect reconstruction following malignant tumor removal of limbs using perforator propeller flaps. Between July 2008 and July 2015, 19 patients with malignant limb tumor underwent defect reconstruction following tumor removal using the perforator propeller flaps. There were 13 males and 6 females with an average age of 53.4 years (range, 20-82 years). The disease duration ranged from 1 to 420 months (mean, 82 months). The tumors located at the thigh in 10 cases, at the leg in 2 cases, at the arm in 1 case, at the forearm in 1 case, around the knee in 2 cases, and around the elbow joint in 3 cases. Totally 23 flaps (from 8 cm x 3 cm to 30 cm x 13 cm in size) were used to reconstruct defects (from 4 cm x 4 cm to 24 cm x 16 cm in size). The potential source arteries included the femoral artery (n = 2), profunda femoral artery (n = 3), superficial circumflex iliac artery (n = 1), lateral circumflex femoral artery (n = 6), superior lateral genicular artery (n = 2), peroneal artery (n = 2), anterior tibial artery (n = 1), brachial artery (n = 4), and radial artery (n = 1). The remaining one was a free style perforator flap. Partial distal flap necrosis occurred in 3 cases after surgery with rotation angles of 180, 150, and 100 degrees respectively, which were reconstructed after debridement using a free-style perforator flap in 1 case and using free skin grafting in the other 2 cases. The other 20 flaps survived completely after surgery. Primary healing of incisions was obtained at the donor and recipient sites. There was no severe complication such as infection, hematoma, and total flap failure. All patients were followed up 3 months to 5 years (mean, 19 months). One patient with malignant melanoma around the elbow joint had tumor recurrence, and underwent secondary tumor resection. The appearance, texture, and color of the flaps were similar to those at the recipient site. For patients with malignant tumor of the limb, the perforator propeller flap can be an alternative option for soft tissue defect reconstruction after tumor resection, with the advantages of relatively simple operation and remaining the main vessels.

The Propeller and Cooling-Air-Flow Characteristics of a Twin-Engine Airplane Model Equipped with NACA D sub s -Type Cowlings and with Propellers of NACA 16-Series Airfoil Sections

DTIC Science & Technology

1944-09-01

with the cowling flaps neutral, did not in any case exceed T] = ±0.03. Drag and Cowling-Air Plow with Propeller Removed The effects, on the lift...cowling flaps. Effect of internal flow on drar.- For convenience in studying the drf.g oharaoterlstio a of the two cowling arrangement•, values of the...operation and take-off. Influence of Cooling Hequireir;ent3 on Airplane Performance In the case of many conventional radial elr-ccoled engine

Lateral orbital propeller flap technique for reconstruction of the lower eyelid defect.

PubMed

Ding, J-P; Chen, B; Yao, J

2018-05-01

The lower eyelid, which has a unique anatomy and esthetic importance, is a common site of basal cell carcinoma. The reconstruction of the defect after the wide excision of the tumour is a special concern of many plastic surgeons. How to achieve the most satisfying effect through minimal invasive is important for patients. We successfully applied the lateral orbital propeller flap for one-stage reconstruction of a large lower eyelid defect after tumour resection. We consider that this flap can achieve better tissue mobilisation as it provides effective coverage of soft tissue defects and thus is especially useful for repairing facial defects.

A Non-linear Lifting Line Model for Design and Analysis of Trochoidal Propulsors

NASA Astrophysics Data System (ADS)

Roesler, Bernard; Epps, Brenden

2014-11-01

Flapping wing propulsors may increase the propulsive efficiency of large shipping vessels. A comparison of the design of a notional propulsor for a large shipping vessel with (a) a conventional ducted propeller versus (b) a flapping wing propulsor is presented. Calculations for flapping wing propulsors are performed using an open-source MATLAB software suite developed by the authors, CyROD, implementing an unsteady lifting-line model with free vortex wake roll-up to study the non-linear effects of foil-wake, and foil-foil interactions. Improvements to the traditional lifting line theory are made using further discretization of the wake vortex ring spacing near the trailing edge. Considerations of packaging options for a flapping wing propulsor on a large shipping vessel are presented, and compared with those for a conventional ducted propeller.

Swimming micro-robot powered by stimuli-sensitive gel

NASA Astrophysics Data System (ADS)

Masoud, Hassan; Alexeev, Alexander

2012-11-01

Using three-dimensional computer simulations, we design a simple maneuverable micro-swimmer that can self-propel and navigate in highly viscous (low Reynolds-number) environments. Our simple swimmer consists of a cubic gel body which periodically changes volume in response to external stimuli, two rigid rectangular flaps attached to the opposite sides of the gel body, and a flexible steering flap at the front end of the swimmer. The stimuli-sensitive body undergoes periodic expansions (swelling) and contractions (deswelling) leading to a time-irreversible beating motion of the propulsive flaps that propel the micro-swimmer. Thus, the responsive gel body acts as an ``engine'' actuating the motion of the swimmer. We examine how the swimming speed depends on the gel and flap properties. We also probe how the swimmer trajectory can be changed using a responsive steering flap whose curvature is controlled by an external stimulus. We show that the turning occurs due to steering flap bending and periodic beating. Furthermore, our simulations reveal that the turning direction can be regulated by changing the intensity of external stimulus.

Comparison of Three Exit-Area Control Devices on an N.A.C.A. Cowling, Special Report

NASA Technical Reports Server (NTRS)

McHugh, James G.

1940-01-01

Adjustable cowling flaps, an adjustable-length cowling skirt, and a bottom opening with adjustable flap were tested as means of controlling the rate of cooling-air flow through an air-cooled radial-engine cowling. The devices were tested in the NACA 20-foot tunnel on a model wing-nacelle-propeller combination, through an airspeed range of 20 to 80 miles per hour, and with the propeller blade angle set 23 degrees at 0.75 of the tip radius. The resistance of the engine to air flow through the cowling was simulated by a perforated plate. The results indicated that the adjustable cowling flap and the bottom opening with adjustable flap were about equally effective on the basis of pressure drop obtainable and that both were more effective means of increasing the pressure drop through the cowling than the adjustable-length skirt. At conditions of equal cooling-air flow, the net efficiency obtained with the adjustable cowling flaps and the adjustable-length cowling skirt was about 1% greater than the net efficiency obtained with the bottom opening with adjustable flap.

Viscous investigation of a flapping foil propulsor

NASA Astrophysics Data System (ADS)

Posri, Attapol; Phoemsapthawee, Surasak; Thaweewat, Nonthipat

2018-01-01

Inspired by how fishes propel themselves, a flapping-foil device is invented as an alternative propulsion system for ships and boats. The performance of such propulsor has been formerly investigated using a potential flow code. The simulation results have shown that the device has high propulsive efficiency over a wide range of operation. However, the potential flow gives good results only when flow separation is not present. In case of high flapping frequency, the flow separation can occur over a short instant due to fluid viscosity and high angle of attack. This may cause a reduction of propulsive efficiency. A commercial CFD code based on Lattice Boltzmann Method, XFlow, is then employed in order to investigate the viscous effect over the propulsive performance of the flapping foil. The viscous results agree well with the potential flow results, confirming the high efficiency of the propulsor. As expected, viscous results show lower efficiency in high flapping frequency zone.

The "chimeric" trapezius muscle and fasciocutaneous flap (dorsal scapular artery perforator flap): a new design for complex 3-dimensional defects.

PubMed

Rozen, Warren M; Fox, Carly M; Leong, James; Morsi, Adel

2013-11-01

Multiple variations of the musculocutaneous trapezius flap have been described, each of which use a single composite musculocutaneous unit in their designs. The limitation of such designs is the ability to use the components in a 3-dimensional manner, with only 1 vector existing in the geometry of the musculocutaneous unit. A review of the literature was undertaken with regard to designs of the musculocutaneous trapezius flap, and we present a new technique for flap design. With identification of individual perforators to each of the muscle and fasciocutaneous portions of the trapezius flap, the 2 components can act in a chimeric fashion, able to fill both a deep and complex 3-dimensional space while covering the wound with robust skin. A range of flap designs have been described, including transverse, oblique, and vertical skin paddles accompanying the trapezius muscle. We describe a technique with which a propeller-style skin paddle based on a cutaneous perforator can be raised in any orientation with respect to the underlying muscle. In a presented case, separation of the muscular and fasciocutaneous components of the trapezius flap was able to obliterate dead space around exposed cervicothoracic spinal metalwork and obtain robust wound closure in a patient with previous radiotherapy. This concomitant use of a muscle and fasciocutaneous perforator flap based on a single perforator, a so-called chimeric perforator flap, is a useful modification to trapezius musculocutaneous flap design.

Reynolds Number Effects on Thrust Coefficients and PIV for Flapping Wing Micro Air Vehicles

DTIC Science & Technology

2012-03-09

flapper and smallest gear attached to the drive shaft from the motor. Lastly, passive rotation stops were designed and printed using the Objet Eden 500V...for different flapping mechanisms are also compared to a rotating propeller with the goal of elucidating the design trade space between rotorcraft and...flapping wings at Reynolds numbers less than 100,000. One flapping-wing mechanism was designed to incorporate a coupled 4-bar planar and 4-bar

Fluid-Structure Interaction Effects on Mass Flow Rates in Solid Rocket Motors

DTIC Science & Technology

2015-09-02

FEA ) is explored. A propellant flap in a cross flow is analyzed. Comparisons are made between an analytical solution, a solely CFD solution, a manual...finite element analysis ( FEA ) is explored.  A  propellant flap in a cross flow is analyzed.  Comparisons are made between an analytical  solution, a...Condition Zones ..................................................................... 11  Figure 6: Pressure Boundary Condition Applied to  FEA  model

Aerodynamic characteristics of a propeller-powered high-lift semispan wing

NASA Technical Reports Server (NTRS)

Gentry, Garl L., Jr.; Takallu, M. A.; Applin, Zachary T.

1994-01-01

A small-scale semispan high-lift wing-flap system equipped under the wing with a turboprop engine assembly was tested in the LaRC 14- by 22-Foot Subsonic Tunnel. Experimental data were obtained for various propeller rotational speeds, nacelle locations, and nacelle inclinations. To isolate the effects of the high lift system, data were obtained with and without the flaps and leading-edge device. The effects of the propeller slipstream on the overall longitudinal aerodynamic characteristics of the wing-propeller assembly were examined. Test results indicated that the lift coefficient of the wing could be increased by the propeller slipstream when the rotational speed was increased and high-lift devices were deployed. Decreasing the nacelle inclination (increased pitch down) enhanced the lift performance of the system much more than varying the vertical or horizontal location of the nacelle. Furthermore, decreasing the nacelle inclination led to higher lift curve slope values, which indicated that the powered wing could sustain higher angles of attack near maximum lift performance. Any lift augmentation was accompanied by a drag penalty due to the increased wing lift.

Propulsion of a flapping and oscillating airfoil

NASA Technical Reports Server (NTRS)

Garrick, I E

1937-01-01

Formulas are given for the propelling or drag force experience in a uniform air stream by an airfoil or an airfoil-aileron combination, oscillating in any of three degrees of freedom; vertical flapping, torsional oscillations about a fixed axis parallel to the span, and angular oscillations of the aileron about a hinge.

[Locoregional solutions for groin defects : Coverage after vascular surgery].

PubMed

Cerny, M; Harder, Y; Zimmermann, A; Eckstein, H-H; Machens, H-G; Schantz, J-T; Schenck, T L

2017-01-01

Vascular surgery through a groin incision may be associated with severe wound healing disorders in this sensitive area. There are many options to reconstruct the defect surgically. The choice of surgical reconstruction depends mainly on the individual status of vasculature, which is most often compromised in these patients. There are random pattern flaps, as well as perforator, pedicled flaps or microvascular flaps to choose from. We give an overview of plastic surgical solutions for groin defects, with a special focus on complex wounds after vascular surgical complications. We discuss advantages and disadvantages of different flaps with two case reports and also show alternatives. We demonstrate in two cases how the reconstruction of the groin defect was planned, taking into account the vascular status, and why we chose an innovative and seldom-used option in each case. The selected flaps, a pedicled fasciocutaneous ALT propeller flap and a perforator-based, pedicled abdominal advancement flap reconstructed the defects successfully. The surgical therapy for the reconstruction of groin defects should be chosen according to the individual vascular status to ensure safe and reliable blood supply. To guarantee the best possible reconstruction and avoid postoperative healing disorders and infections, less common flaps should also be considered.

Large-Scale Wind-Tunnel Tests of an Airplane Model with an Unswept, Tilt Wing of Aspect Ratio 5.5, and with Four Propellers and Blowing Flaps

NASA Technical Reports Server (NTRS)

Weiberg, James A.; Holzhauser, Curt A.

1961-01-01

Tests were made of a large-scale tilt-wing deflected-slipstream VTOL airplane with blowing-type BLC trailing-edge flaps. The model was tested with flap deflections of 0 deg. without BLC, 50 deg. with and without BLC, and 80 deg. with BLC for wing-tilt angles of 0, 30, and 50 deg. Included are results of tests of the model equipped with a leading-edge flap and the results of tests of the model in the presence of a ground plane.

Wing flapping with minimum energy. [minimize the drag for a bending moment at the wing root

NASA Technical Reports Server (NTRS)

Jones, R. T.

1980-01-01

For slow flapping motions it is found that the minimum energy loss occurs when the vortex wake moves as a rigid surface that rotates about the wing root - a condition analogous to that determined for a slow-turning propeller. The optimum circulation distribution determined by this condition differs from the elliptic distribution, showing a greater concentration of lift toward the tips. It appears that very high propulsive efficiencies are obtained by flapping.

Helicopter problems

NASA Technical Reports Server (NTRS)

Kussner, H G

1937-01-01

The present report deals with a number of the main problems requiring solution in the development of helicopters and concerning the lift, flying performance, stability, and drive. A complete solution is given for the stability of the helicopter with rigid blades and control surfaces. With a view to making a direct-lift propeller sufficient without the addition of auxiliary propellers, the "flapping drive" is assessed and its efficiency calculated.

Propeller flap for treatment of a poststernotomy sternal fistula: a case report.

PubMed

Corradino, Bartolo; Di Lorenzo, Sara; Hubova, Martina; Cordova, Adriana

2014-11-01

The treatment of post-operative deep sternal wound infections is a real challenge for surgeons. Conservative treatment with debridement and vacuum-assisted closure (VAC) therapy is not always successful. In the most severe and chronic cases, a surgical debridement and reconstruction of the defect is mandatory. In this report, the authors present a case of a 61-year-old female patient with a chronic cutaneous fistula in the sternal region following a median sternotomy after coronary artery bypass. The patient had already undergone treatment with antibiotics, drainage of an abscess and local debridement, but the infection continued to relapse periodically. The authors decided to treat the fistula with debridement and reconstruction with a local freestyle propeller flap mobilised from the right parasternal region. The fistula healed without any complications. There has been no relapse, and the aesthetic result is satisfactory. The scar at the donor site is acceptable with a minimum alteration to the mammary region. Sternal fistulas after medial sternotomy are difficult to treat. The treatment method of debridement followed, in certain cases, by VAC therapy is quite controversial. A surgical procedure is sometimes necessary to speed healing. Mobilisation of a freestyle propeller flap represents a less invasive surgical approach to the treatment of sternal fistulas in cases of conservative treatment failure. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Performance Analysis of a Self-Propelling Flat Plate Fin with Joint Compliance

NASA Astrophysics Data System (ADS)

Reddy, N. Srinivasa; Sen, Soumen; Pal, Sumit; Shome, Sankar Nath

2017-12-01

Fish fin muscles are compliant and they regulate the stiffness to suit different swimming conditions. This article attempts to understand the significance of presence of compliance in fin muscle with help of a flexible joint flat plate fin model. Blade element method is employed to model hydrodynamics and to compute the forces of interaction during motion of the plate within fluid. The dynamic model of self-propelling fin is developed through multi-body dynamics approach considering the hydrodynamic forces as external forces acting on the fin. The derived hydrodynamic model is validated with experiments on rigid flat plate fin. The effect of the joint stiffness and flapping frequency on the propulsion speed and efficiency is investigated through simulations using the derived and validated model. The propulsion efficiency is found to be highly influenced by the joint stiffness at a given flapping frequency. The fin attained maximum propulsion efficiency when the joint stiffness is tuned to a value at which flapping frequency matches near natural frequency of the fin. At this tuned joint stiffness and flapping frequency, the resulted Strouhal numbers are observed to fall within the optimum range (0.2 to 0.4) for maximized propulsion efficiency of flying birds and swimming aquatic animals reported in literature.

On Wind Tunnel Tests and Computations Concerning the Problem of Shrouded Propellers

NASA Technical Reports Server (NTRS)

Kruger, W.

1949-01-01

Results of measurements on a shrouded propeller are given. The propeller is designed for the high ratio of advance and high thrust loading. The effect of the shape of propeller and shroud upon the aerodynamic coefficients of the propulsion unit can be seen from the results. The highest efficiency measured is 0.71. The measurements permit the conclusion that the maximum efficiency can be essentially improved by shroud profiles of small chord and thickness. The largest static thrust factor of merit measured reaches according to Bendemann, a value of about zeta = 1.1. By the use of a nose split flap the static thrust for thin shroud profiles with small nose radius can be about doubled. In a separate section numerical investigations of the behavior of shrouded propellers for the ideal case and for the case with energy losses are carried out. The calculations are based on the assumption that the slipstream cross section depends solely on the shape of the shroud and not on the propeller loading. The reliability of this hypothesis is confirmed experimentally and by flow photographs for a shroud with small circulation. Calculation and test are also in good agreement concerning efficiency and static thrust factor of merit. The prospects of applicability for shrouded propellers and their essential advantages are discussed.

The Anterior Interosseus Artery Perforator Flap: Anatomical Dissections and Clinical Study.

PubMed

Panse, Nikhil S; Joshi, Sheetal B; Sahasrabudhe, Parag B; Bahetee, B; Gurude, Pradnya; Chandanwale, Ajay

2017-05-01

Reconstruction of upper extremity deformities continues to be a challenge to the reconstructive surgeon. Various loco regional, distant and free flaps are available for reconstruction. However, each has its own set of advantages and disadvantages. Of the commonly performed local flaps, radial artery forearm flap, and the posterior interosseus artery flap stand out prominently. Recently, perforator propeller flaps have been used for resurfacing the upper extremity. The anterior interosseus artery perforator flap is an uncommonly used and described flap. This study was divided into anatomical study and clinical application in a IV level of evidence. In the anatomical study, five upper extremities were studied. Clinically, 12 patients underwent reconstruction using the anterior interosseus artery perforator flap. Flaps were performed by a single surgeon. A retrospective review of these cases from November 2008 to May 2014 is presented. The anterior interosseus artery perforator was identified in four out of five cadaver limbs. The septocutaneous perforator was in the fifth extensor compartment around 4 cm proximal to the wrist joint. Of the twelve flaps, there was complete necrosis in one flap, and partial necrosis in one flap. The patient with complete necrosis underwent skin grafting at a later date. The wound healed secondarily in case of partial flap necrosis. Anterior interosseus artery perforator flap must be considered as an important reconstructive option in the armamentarium of the plastic surgeon, while managing hand and wrist defects.

Joint High Speed Sealift (JHSS) Baseline Shaft & Strut (BSS) Model 5653-3: Series 2, Propeller Disk LDV Wake Survey; and Series 3, Stock Propeller Powering and Stern Flap Evaluation Experiments

DTIC Science & Technology

2007-09-01

B27 B3b. Open water performance characteristics, stock propellers 5234 and 5235 ................... B28 B4. Principal dimensions of...n~nu~ .. *ASA B27 B3b. Open water performance characteristics, stock propellers 5234 and 5235 5234 5235 FAMED OPEN WATER COEFFICIENTS FOR PROPELLER...LA V 00 H MN 0𔃾 LAW M 00 MN4 0 ( LA M 4. ~ ~ ~ ~ r 4. LALA (0 m N 0 0 H H- H H H Hm H H vN( N( N((((m 4 HmmN N4 L 0 .( N ( ( HW H HLA mL (n(mNHO H

An experimental and analytical investigation of proprotor whirl flutter

NASA Technical Reports Server (NTRS)

Kvaternik, R. G.; Kohn, J. S.

1977-01-01

The results of an experimental parametric investigation of whirl flutter are presented for a model consisting of a windmilling propeller-rotor, or proprotor, having blades with offset flapping hinges mounted on a rigid pylon with flexibility in pitch and yaw. The investigation was motivated by the need to establish a large data base from which to assess the predictability of whirl flutter for a proprotor since some question has been raised as to whether flutter in the forward whirl mode could be predicted with confidence. To provide the necessary data base, the parametric study included variation in the pylon pitch and yaw stiffnesses, flapping hinge offset, and blade kinematic pitch-flap coupling over a large range of advance ratios. Cases of forward whirl flutter and of backward whirl flutter are documented. Measured whirl flutter characteristics were shown to be in good agreement with predictions from two different linear stability analyses which employed simple, two dimensional, quasi-steady aerodynamics for the blade loading. On the basis of these results, it appears that proprotor whirl flutter, both forward and backward, can be predicted.

Hydrodynamic schooling of flapping swimmers

NASA Astrophysics Data System (ADS)

Becker, Alexander D.; Masoud, Hassan; Newbolt, Joel W.; Shelley, Michael; Ristroph, Leif

2015-10-01

Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing-wake interactions. Simulations show that swimming in a group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. These results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups.

Hydrodynamic schooling of flapping swimmers

DOE PAGES

Becker, Alexander D.; Masoud, Hassan; Newbolt, Joel W.; ...

2015-10-06

Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing–wake interactions. Simulations show that swimming in amore » group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. Lastly, these results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups.« less

A dynamical system for interacting flapping swimmers

NASA Astrophysics Data System (ADS)

Oza, Anand; Ramananarivo, Sophie; Ristroph, Leif; Shelley, Michael

2015-11-01

We present the results of a theoretical investigation into the dynamics of interacting flapping swimmers. Our study is motivated by the recent experiments of Becker et al., who studied a one-dimensional array of self-propelled flapping wings that swim within each other's wakes in a water tank. They discovered that the system adopts certain ``schooling modes'' characterized by specific spatial phase relationships between swimmers. To rationalize these phenomena, we develop a discrete dynamical system in which the swimmers are modeled as heaving airfoils that shed point vortices during each flapping cycle. We then apply our model to recent experiments in the Applied Math Lab, in which two tandem flapping airfoils are free to choose both their speed and relative positions. We expect that our model may be used to understand how schooling behavior is influenced by hydrodynamics in more general contexts. Thanks to the NSF for its support.

The Anterior Interosseus Artery Perforator Flap: Anatomical Dissections and Clinical Study

PubMed Central

Panse, Nikhil S; Joshi, Sheetal B; Sahasrabudhe, Parag B; Bahetee, B; Gurude, Pradnya; Chandanwale, Ajay

2017-01-01

BACKGROUND Reconstruction of upper extremity deformities continues to be a challenge to the reconstructive surgeon. Various loco regional, distant and free flaps are available for reconstruction. However, each has its own set of advantages and disadvantages. Of the commonly performed local flaps, radial artery forearm flap, and the posterior interosseus artery flap stand out prominently. Recently, perforator propeller flaps have been used for resurfacing the upper extremity. The anterior interosseus artery perforator flap is an uncommonly used and described flap. METHODS This study was divided into anatomical study and clinical application in a IV level of evidence. In the anatomical study, five upper extremities were studied. Clinically, 12 patients underwent reconstruction using the anterior interosseus artery perforator flap. Flaps were performed by a single surgeon. A retrospective review of these cases from November 2008 to May 2014 is presented. RESULTS The anterior interosseus artery perforator was identified in four out of five cadaver limbs. The septocutaneous perforator was in the fifth extensor compartment around 4 cm proximal to the wrist joint. Of the twelve flaps, there was complete necrosis in one flap, and partial necrosis in one flap. The patient with complete necrosis underwent skin grafting at a later date. The wound healed secondarily in case of partial flap necrosis. CONCLUSION Anterior interosseus artery perforator flap must be considered as an important reconstructive option in the armamentarium of the plastic surgeon, while managing hand and wrist defects. PMID:28713704

Cooling of Airplane Engines at Low Air Speeds

NASA Technical Reports Server (NTRS)

Theodorsen, Theodore; Brevoort, M J; Stickle, George W

1937-01-01

Report presents the results of a comprehensive experimental study carried out at full scale in the NACA 20-foot wind tunnel, the general purpose of which is to furnish information in regard to the functioning of the power plant and propeller unit under different conditions. This report deals particularly with the problem of the cooling of an airplane engines on the ground. The influence of different nose forms, skirts, flaps, propellers, spinners, and special blowers has been investigated.

Full-scale Wind-tunnel and Flight Tests of a Fairchild 22 Airplane Equipped with External-airfoil Flaps

NASA Technical Reports Server (NTRS)

Reed, Warren D; Clay, William C

1937-01-01

Wind-tunnel and flight tests have been made of a Fairchild 22 airplane equipped with a wing having external-airfoil flaps that also perform the function of ailerons. Lift, drag, and pitching-moment coefficients of the airplane with several flap settings, and the rolling- and yawing-moment coefficients with the flaps deflected as ailerons were measured in the full-scale tunnel with the horizontal tail surfaces and propeller removed. The effect of the flaps on the low speed and on the take-off and landing characteristics, the effectiveness of flaps when used as ailerons, and the forces required to operate them as ailerons were determined in flight. The wind-tunnel tests showed that the flaps increased the maximum lift coefficient of the airplane from 1.51 with the flap in the minimum drag position to 2.12 with the flap in the minimum drag position to 2.12 with the flap deflected 30 degrees. In the flight tests the minimum speed decreased from 46.8 miles per hour with the flaps up to 41.3 miles per hour with the flaps deflected. The required take-off run to attain a height of 50 feet was reduced from 820 to 750 feet and the landing run from a height of 50 feet was reduced from 930 to 480 feet. The flaps for this installation gave lateral control that was not entirely satisfactory. Their rolling action was good but the adverse yaw resulting from their use was greater than is considerable, and the stick forces required to operate them increased too rapidly with speed.

Lower Extremity Reconstruction with Free Gracilis Flaps

PubMed Central

Nicoson, Michael C; Parikh, Rajiv P; Tung, Thomas H

2017-01-01

Background There have been significant advancements in lower extremity reconstruction over the last several decades, and the plastic surgeon’s armamentarium has grown to include free muscle and fasciocutaneous flaps along with local perforator and propeller flaps. While we have found a use for a variety of techniques for lower extremity reconstruction, the free gracilis has been our workhorse flap due to the ease of harvest, reliability, and low donor site morbidity. Methods This is a retrospective review of a single surgeon’s series of free gracilis flaps utilized for lower extremity reconstruction. Demographic information, comorbidities, outcomes and secondary procedures were analyzed. Results We identified 24 free gracilis flaps. The duration from injury to free flap coverage was 7 days or less in 6 patients, 8–30 days in 11 patients, 31–90 days in 4 patients, and > 90 days in 3 patients. There were 22 (92%) successful flaps and an overall limb salvage rate of 92%. There was one partial flap loss. Two flaps underwent incision and drainage in the operating room for infection. Two patients developed donor site hematomas. Four patients underwent secondary procedures for contouring. Our subset of pediatric patients had 100% flap survival and no secondary procedures at a mean 30 month follow up. Conclusions This study demonstrates the utility of the free gracilis flap in reconstruction of small to medium sized defects of the lower extremity. This flap has a high success rate and low donor site morbidity. Atrophy of the denervated muscle over time allows for good shoe fit, often obviating the need for secondary contouring procedures. PMID:28024305

Wake Characteristics of a Flapping Wing Optimized for both Aerial and Aquatic Flight

NASA Astrophysics Data System (ADS)

Izraelevitz, Jacob; Kotidis, Miranda; Triantafyllou, Michael

2017-11-01

Multiple aquatic bird species (including murres, puffins, and other auks) employ a single actuator to propel themselves in two different fluid media: both flying and swimming using primarily their flapping wings. This impressive design compromise could be adopted by engineered implementations of dual aerial/aquatic robotic platforms, as it offers an existence proof for favorable flow physics. We discuss one realization of a 3D flapping wing actuation system for use in both air and water. The wing oscillates by the root and employs an active in-line motion degree-of-freedom. An experiment-coupled optimization routine generates the wing trajectories, controlling the unsteady forces throughout each flapping cycle. We elucidate the wakes of these wing trajectories using dye visualization, correlating the wake vortex structures with simultaneous force measurements. After optimization, the wing generates the large force envelope necessary for propulsion in both fluid media, and furthermore, demonstrate improved control over the unsteady wake.

Initial piloted simulation study of geared flap control for tilt-wing V/STOL aircraft

NASA Technical Reports Server (NTRS)

Guerrero, Lourdes M.; Corliss, Lloyd D.

1991-01-01

A simulation study of a representative tilt wing transport aircraft was conducted in 1990 on the Ames Vertical Motion Simulator. This simulation is in response to renewed interest in the tilt wing concept for use in future military and civil applications. For past tilt wing concepts, pitch control in hover and low-speed flight has required a tail rotor or reaction jets at the tail. Use of mono cyclic propellers or a geared flap have also been proposed as alternate methods for providing pitch control at low speed. The geared flap is a subject of this current study. This report describes the geared flap concept, the tilt wing aircraft, the simulation model, the simulation facility and experiment setup, the pilots' evaluation tasks and procedures, and the results obtained from the simulation experiment. The pilot evaluations and comments are also documented in the report appendix.

Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance.

PubMed

Ramananarivo, Sophie; Godoy-Diana, Ramiro; Thiria, Benjamin

2011-04-12

Saving energy and enhancing performance are secular preoccupations shared by both nature and human beings. In animal locomotion, flapping flyers or swimmers rely on the flexibility of their wings or body to passively increase their efficiency using an appropriate cycle of storing and releasing elastic energy. Despite the convergence of many observations pointing out this feature, the underlying mechanisms explaining how the elastic nature of the wings is related to propulsive efficiency remain unclear. Here we use an experiment with a self-propelled simplified insect model allowing to show how wing compliance governs the performance of flapping flyers. Reducing the description of the flapping wing to a forced oscillator model, we pinpoint different nonlinear effects that can account for the observed behavior--in particular a set of cubic nonlinearities coming from the clamped-free beam equation used to model the wing and a quadratic damping term representing the fluid drag associated to the fast flapping motion. In contrast to what has been repeatedly suggested in the literature, we show that flapping flyers optimize their performance not by especially looking for resonance to achieve larger flapping amplitudes with less effort, but by tuning the temporal evolution of the wing shape (i.e., the phase dynamics in the oscillator model) to optimize the aerodynamics.

Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance

PubMed Central

Ramananarivo, Sophie; Godoy-Diana, Ramiro; Thiria, Benjamin

2011-01-01

Saving energy and enhancing performance are secular preoccupations shared by both nature and human beings. In animal locomotion, flapping flyers or swimmers rely on the flexibility of their wings or body to passively increase their efficiency using an appropriate cycle of storing and releasing elastic energy. Despite the convergence of many observations pointing out this feature, the underlying mechanisms explaining how the elastic nature of the wings is related to propulsive efficiency remain unclear. Here we use an experiment with a self-propelled simplified insect model allowing to show how wing compliance governs the performance of flapping flyers. Reducing the description of the flapping wing to a forced oscillator model, we pinpoint different nonlinear effects that can account for the observed behavior—in particular a set of cubic nonlinearities coming from the clamped-free beam equation used to model the wing and a quadratic damping term representing the fluid drag associated to the fast flapping motion. In contrast to what has been repeatedly suggested in the literature, we show that flapping flyers optimize their performance not by especially looking for resonance to achieve larger flapping amplitudes with less effort, but by tuning the temporal evolution of the wing shape (i.e., the phase dynamics in the oscillator model) to optimize the aerodynamics. PMID:21444774

A Brief Study of the Speed Reduction of Overtaking Airplanes by Means of Air Brakes, Special Report

NASA Technical Reports Server (NTRS)

Pearson, H. A.; Amderspm. R. F.

1942-01-01

As an aid to airplane designers interested in providing pursuit airplanes with decelerating devices intended to increase the firing time when overtaking another airplane, formulas are given relating the pertinent distances and speeds in horizontal flight to the drag increase required. Charts are given for a representative parasite-drag coefficient from which the drag increase, the time gained, and the closing distance may be found. The charts are made up for three values of the ratio of the final speed of the pursuing airplane to the speed of the pursued airplane and for several values of the ratio of the speed of the pursued airplane to the initial speed of the pursuing airplane. Charts are also given indicating the drag increases obtainable with double split flaps and with conventional propellers. The use of the charts is illustrated by an example in which it is indicated that either double split flaps or, under certain ideal conditions, reversible propellers should provide the speed reductions required.

Preliminary flight-test results of an advanced technology light twin-engine airplane /ATLIT/

NASA Technical Reports Server (NTRS)

Holmes, B. J.; Kohlman, D. L.; Crane, H. L.

1976-01-01

The present status and flight-test results are presented for the ATLIT airplane. The ATLIT is a Piper PA-34 Seneca I modified by the installation of new wings incorporating the GA(W)-1 (Whitcomb) airfoil, reduced wing area, roll-control spoilers, and full-span Fowler flaps. Flight-test results on stall and spoiler roll characteristics show good agreement with wind-tunnel data. Maximum power-off lift coefficients are greater than 3.0 with flaps deflected 37 deg. With flaps down, spoiler deflections can produce roll helix angles in excess of 0.11 rad. Flight testing is planned to document climb and cruise performance, and supercritical propeller performance and noise characteristics. The airplane is scheduled for testing in the NASA-Langley Research Center Full-Scale Tunnel.

Close range gun shot injuries of the hand with the "mole gun".

PubMed

Keskin, Mustafa; Beydes, Tolga; Tosun, Zekeriya; Savaci, Nedim

2009-07-01

A mole gun is a handmade weapon used as a trap to kill moles by farmers. Their action is based on a simple hammer mechanism: when the moles put their head through the metal ring to get hold of the food, they trigger the mechanism. The hammer strikes the primer, which ignites the gunpowder, propelling the pellets from the barrel. The purpose of this study was to report our experiences in a group of patients who accidentally suffered injuries by mole guns to the hand. Since 2000, 20 patients had attended the clinic with mole gun shot injuries to the hand. The mean age of patients was 38 years. Thirteen cases involved skin defects over the dorsum of the hand associated with extensor tendon and bone injuries. The skin defect was covered with posterior interosseous artery (PIA) flap in 12 cases. In one case, the PIA pedicle was found to be injured so radial forearm flap was used. The main intervention time for these cases was 6.2 days. All flaps except two PIA flap survived uneventfully. One flap was completely lost while other survived with distal necrosis. In remaining seven cases the thumb was the main injured part; it had complete disruption of its arterial supply and was managed with amputation with or without matarcarpal removal. These cases were managed immediately. The risk of injury to the PIA by pellets is low in such close range shots to the hand and PIA flap could be used to cover the defects. In such cases, initial debridement should be minimal and the soft tissue, tendon, and bone injury can be managed in the same stage during the first week of injury.

Sea Butterfly Swimming: Time-resolved Tomographic PIV measurements

NASA Astrophysics Data System (ADS)

Murphy, David; Zheng, Lingxiao; Mittal, Rajat; Webster, Donald; Yen, Jeannette

2011-11-01

The planktonic sea butterfly Limacina helicina swims by flapping its flexible, wing-like parapodia. The appendage stroke kinematics of this shell-bearing pteropod are three-dimensional and likely contain elements of both drag-based (rowing) and lift-based (flapping) propulsion. Unsteady lift-generating mechanisms such as clap-and-fling may also be present. Upstroke and downstroke motions both propel the animal upward and roll it forwards and backwards, resulting in a sawtooth trajectory. We present time-resolved, tomographic PIV measurements of flow generated by free-swimming pteropods (Limacina helicina) moving upwards with average swimming speeds of 5 - 17 mm/s. The pteropods beat their appendages with a stroke frequency of 4 - 5 Hz. With a size range of 1 - 2 mm, the animals filmed in this study operate in a viscous environment with a Reynolds number of 5 to 20. The volumetric flow measurements provide insight into the three dimensional nature of the flow and into the relative importance of drag- and lift-based propulsion at this low Reynolds number. Preliminary results from Navier-Stokes simulations of the flow associated with the swimming of this organism will also be presented.

Efficiency enhancement of a self-propelled pitching profile using non-sinusoidal trajectories

NASA Astrophysics Data System (ADS)

Mekadem, M.; Chihani, E.; Oualli, H.; Hanchi, S.; Bouabdallah, A.; Gad-El-Hak, M.

2017-11-01

A symmetrical profile is subjected to non-sinusoidal pitching motion. The airfoil has a chord length c = 0.006 m and a semi-circular leading edge with a diameter of D = 0.001 m. The extrados and intrados are two straight lines that intersect at a tapered trailing edge, and the pitching pivot point is positioned at the leading edge. The pitching frequency is in the range of 1 <= f <= 190 Hz, while the tangential amplitude of the flapping trailing edge varies from 18% to 114% of the foil cord. To improve the airfoil propulsive performance, two-dimensional numerical simulations are implemented on FLUENT. The Reynolds number based upon the maximum profile thickness D varies in the range of 35 <= Re <= 210 , which matches insect's Reynolds numbers. The foil movement is executed using the dynamic mesh technique and a user defined function (UDF). The adopted mesh has 70,445 nodes with 5,1960 quadrilateral cells. The results are in good agreement with prior experiments, and, compared to sinusoidal oscillations, show that non-sinusoidal flapping trajectories lead to advancing velocity increase of 550%. Additionally, if improved propulsive efficiency is sought, non-sinusoidal flapping lead to better thrust.

Influence of wing tip morphology on vortex dynamics of flapping flight

NASA Astrophysics Data System (ADS)

Krishna, Swathi; Mulleners, Karen

2013-11-01

The mechanism of flapping wing flight provides insects with extraordinary flight capabilities. The uniquely shaped wing tips give insects an edge in flight performance and the interaction between the leading edge vortices and wing tip vortices enhance their propelling efficiencies and manoeuvrability. These are qualities that are sought after in current-day Micro Air Vehicles. A detailed understanding of the vortex dynamics of flapping flight and the influence of the wing tip planform is imperative for technical application. An experimental study is conducted to investigate the effects of different wing tip planforms on the formation, evolution and interaction of vortical structures. We thereby focus on the interaction between the coherent structures evolving from the leading edge and the wing tip during pitching and flapping motions.The spatial and temporal evolution of the three-dimensional flow structures are determined using Scanning (Stereo) Particle Image Velocimetry and an in-depth coherent structure analysis. By comparing the vortex dynamics, the aerodynamic performance of various wing tip planforms are evaluated.

Computational Analysis of Powered Lift Augmentation for the LEAPTech Distributed Electric Propulsion Wing

NASA Technical Reports Server (NTRS)

Deere, Karen A.; Viken, Sally A.; Carter, Melissa B.; Viken, Jeffrey K.; Wiese, Michael R.; Farr, Norma L.

2017-01-01

A computational study of a distributed electric propulsion wing with a 40deg flap deflection has been completed using FUN3D. Two lift-augmentation power conditions were compared with the power-off configuration on the high-lift wing (40deg flap) at a 73 mph freestream flow and for a range of angles of attack from -5 degrees to 14 degrees. The computational study also included investigating the benefit of corotating versus counter-rotating propeller spin direction to powered-lift performance. The results indicate a large benefit in lift coefficient, over the entire range of angle of attack studied, by using corotating propellers that all spin counter to the wingtip vortex. For the landing condition, 73 mph, the unpowered 40deg flap configuration achieved a maximum lift coefficient of 2.3. With high-lift blowing the maximum lift coefficient increased to 5.61. Therefore, the lift augmentation is a factor of 2.4. Taking advantage of the fullspan lift augmentation at similar performance means that a wing powered with the distributed electric propulsion system requires only 42 percent of the wing area of the unpowered wing. This technology will allow wings to be 'cruise optimized', meaning that they will be able to fly closer to maximum lift over drag conditions at the design cruise speed of the aircraft.

Structured Finite Volume Modeling of U.S. Navy Aircraft Engine Test Cells Task 2: Turboprop Engine Vol 1

DTIC Science & Technology

1993-06-01

propeller was modeled using an actuator disk model, where in all of the net results of the propeller (wash, swirl, turbulence) are modeled as source...8217)DUCTI* ~ hVAILJZL TV D0*C) ME.UUT FULLY’ LEGIBLE FREPROI)UCTIM 𔃾S \\JiA~v~r (r7, CL w4 bj4 APPENDIX B COPY AVAUAEL TO e MonC DO* IOT flR=1 VULL...dynamics HVAC systems, energy loss measurement, power ARMY FlAP generation) BDG Shore Faciltes 3B Controls and electrical conservation (electrical systems

Wind-Tunnel Investigation of Effects of Unsymmetrical Horizontal-Tail Arrangements on Power-on Static Longitudinal Stability of a Single-Engine Airplane Model

NASA Technical Reports Server (NTRS)

Purser, Paul E.; Spear, Margaret F.

1947-01-01

A wind-tunnel investigation has been made to determine the effects of unsymmetrical horizontal-tail arrangements on the power-on static longitudinal stability of a single-engine single-rotation airplane model. Although the tests and analyses showed that extreme asymmetry in the horizontal tail indicated a reduction in power effects on longitudinal stability for single-engine single-rotation airplanes, the particular "practical" arrangement tested did not show marked improvement. Differences in average downwash between the normal tail arrangement and various other tail arrangements estimated from computed values of propeller-slipstream rotation agreed with values estimated from pitching-moment test data for the flaps-up condition (low thrust and torque) and disagreed for the flaps-down condition (high thrust and torque). This disagreement indicated the necessity for continued research to determine the characteristics of the slip-stream behind various propeller-fuselage-wing combinations. Out-of-trim lateral forces and moments of the unsymmetrical tail arrangements that were best from consideration of longitudinal stability were no greater than those of the normal tail arrangement.

Cooling Tests of an Airplane Equipped with an NACA Cowling and a Wing-duct Cooling System

NASA Technical Reports Server (NTRS)

Turner, L I , Jr; Bierman, David; Boothy, W B

1941-01-01

Cooling tests were made of a Northrop A-17A attack airplane successively equipped with a conventional.NACA cowling and with a wing-duct cooling system. The method of cooling the engine by admitting air from the propeller slipstream into wing ducts, passing it first through the accessory compartment and then over the engine from rear to front, appeared to offer possibilities for improved engine cooling, increased cooling of the accessories, and better fairing of the power-plant installation. The results showed that ground cooling for the wing duct system without cowl flap was better than for the NACA cowling with flap; ground cooling was appreciably improved by installing a cowl flap. Satisfactory temperatures were maintained in both climb and high-speed flight, but, with the use of conventional baffles, a greater quantity of cooling air appeared to be required for the wing duct system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becker, Alexander D.; Masoud, Hassan; Newbolt, Joel W.

Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing–wake interactions. Simulations show that swimming in amore » group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. Lastly, these results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups.« less

A review on robotic fish enabled by ionic polymer-metal composite artificial muscles.

PubMed

Chen, Zheng

2017-01-01

A novel actuating material, which is lightweight, soft, and capable of generating large flapping motion under electrical stimuli, is highly desirable to build energy-efficient and maneuverable bio-inspired underwater robots. Ionic polymer-metal composites are important category of electroactive polymers, since they can generate large bending motions under low actuation voltages. IPMCs are ideal artificial muscles for small-scale and bio-inspired robots. This paper takes a system perspective to review the recent work on IPMC-enabled underwater robots, from modeling, fabrication, and bio-inspired design perspectives. First, a physics-based and control-oriented model of IPMC actuator will be reviewed. Second, a bio-inspired robotic fish propelled by IPMC caudal fin will be presented and a steady-state speed model of the fish will be demonstrated. Third, a novel fabrication process for 3D actuating membrane will be introduced and a bio-inspired robotic manta ray propelled by two IPMC pectoral fins will be demonstrated. Fourth, a 2D maneuverable robotic fish propelled by multiple IPMC fin will be presented. Last, advantages and challenges of using IPMC artificial muscles in bio-inspired robots will be concluded.

Altitude-Wind-Tunnel Investigation of Oil-System Performance of XR-4360-8 Engine in XTB2D-1 Airplane

NASA Technical Reports Server (NTRS)

Conrad, E. William

1946-01-01

An investigation was conducted in the Cleveland altitude wind tunnel to determine the aerodynamic characteristics and the oil delivery critical altitude of the oil-cooler installation of an XTB2D-1 airplane. The investigation was made with the propeller removed end with the engine operating at 1800 brake horsepower, an altitude of 15,000 feet (except for tests of oil-delivery critical altitude), oil-cooler flap deflections from -20 degrees to 20 degrees and inclinations of the thrust axis of 0 degrees, 1.5 degrees, and 6 degrees. At an inclination of the thrust axis of 0 degrees and with the propeller operating, the total-pressure recovery coefficient at the face of the oil cooler varied from 0.84 to 1.10 depending on the flap deflection. With the propeller removed, the best pressure recovery at the face of the oil cooler was obtained at an inclination of the thrust axis of 1.5 degrees. Air-flow separation occurred on the inner surface of the upper lip of the oil-cooler duct inlet at an inclination of the thrust axis of 0 degrees and on the inner surface of the lower lip at 6 degrees. Static pressure coefficients over the duct lips were sufficiently low that no trouble from compressibility would be encountered in level flight. The oil-delivery critical altitude at cruising power (2230 rpm, 1675 bhp) was approximately 18,500 feet for the oil system tested.

Efficient flapping flight of pterosaurs

NASA Astrophysics Data System (ADS)

Strang, Karl Axel

In the late eighteenth century, humans discovered the first pterosaur fossil remains and have been fascinated by their existence ever since. Pterosaurs exploited their membrane wings in a sophisticated manner for flight control and propulsion, and were likely the most efficient and effective flyers ever to inhabit our planet. The flapping gait is a complex combination of motions that sustains and propels an animal in the air. Because pterosaurs were so large with wingspans up to eleven meters, if they could have sustained flapping flight, they would have had to achieve high propulsive efficiencies. Identifying the wing motions that contribute the most to propulsive efficiency is key to understanding pterosaur flight, and therefore to shedding light on flapping flight in general and the design of efficient ornithopters. This study is based on published results for a very well-preserved specimen of Coloborhynchus robustus, for which the joints are well-known and thoroughly described in the literature. Simplifying assumptions are made to estimate the characteristics that can not be inferred directly from the fossil remains. For a given animal, maximizing efficiency is equivalent to minimizing power at a given thrust and speed. We therefore aim at finding the flapping gait, that is the joint motions, that minimize the required flapping power. The power is computed from the aerodynamic forces created during a given wing motion. We develop an unsteady three-dimensional code based on the vortex-lattice method, which correlates well with published results for unsteady motions of rectangular wings. In the aerodynamic model, the rigid pterosaur wing is defined by the position of the bones. In the aeroelastic model, we add the flexibility of the bones and of the wing membrane. The nonlinear structural behavior of the membrane is reduced to a linear modal decomposition, assuming small deflections about the reference wing geometry. The reference wing geometry is computed for the membrane subject to glide loads and pretension from the wing joint positions. The flapping gait is optimized in a two-stage procedure. First the design space is explored using a binary genetic algorithm. The best design points are then used as starting points in a sequential quadratic programming optimization algorithm. This algorithm is used to refine the solutions by precisely satisfying the constraints. The refined solutions are found in generally less than twenty major iterations and constraints are violated generally by less than 0.1%. We find that the optimal motions are in agreement with previous results for simple wing motions. By adding joint motions, the required flapping power is reduced by 7% to 17%. Because of the large uncertainties for some estimates, we investigate the sensitivity of the optimized flapping gait. We find that the optimal motions are sensitive mainly to flight speed, body accelerations, and to the material properties of the wing membrane. The optimal flight speed found correlates well with other studies of pterosaur flapping flight, and is 31% to 37% faster than previous estimates based on glide performance. Accounting for the body accelerations yields an increase of 10% to 16% in required flapping power. When including the aeroelastic effects, the optimal flapping gait is only slightly modified to accommodate for the deflections of stiff membranes. For a flexible membrane, the motion is significantly modified and the power increased by up to 57%. Finally, the flapping gait and required power compare well with published results for similar wing motions. Some published estimates of required power assumed a propulsive efficiency of 100%, whereas the propulsive efficiency computed for Coloborhynchus robustus ranges between 54% and 87%.

Aerodynamic consequences of wing morphing during emulated take-off and gliding in birds.

PubMed

Klaassen van Oorschot, Brett; Mistick, Emily A; Tobalske, Bret W

2016-10-01

Birds morph their wings during a single wingbeat, across flight speeds and among flight modes. Such morphing may allow them to maximize aerodynamic performance, but this assumption remains largely untested. We tested the aerodynamic performance of swept and extended wing postures of 13 raptor species in three families (Accipitridae, Falconidae and Strigidae) using a propeller model to emulate mid-downstroke of flapping during take-off and a wind tunnel to emulate gliding. Based on previous research, we hypothesized that (1) during flapping, wing posture would not affect maximum ratios of vertical and horizontal force coefficients (C V :C H ), and that (2) extended wings would have higher maximum C V :C H when gliding. Contrary to each hypothesis, during flapping, extended wings had, on average, 31% higher maximum C V :C H ratios and 23% higher C V than swept wings across all biologically relevant attack angles (α), and, during gliding, maximum C V :C H ratios were similar for the two postures. Swept wings had 11% higher C V than extended wings in gliding flight, suggesting flow conditions around these flexed raptor wings may be different from those in previous studies of swifts (Apodidae). Phylogenetic affiliation was a poor predictor of wing performance, due in part to high intrafamilial variation. Mass was only significantly correlated with extended wing performance during gliding. We conclude that wing shape has a greater effect on force per unit wing area during flapping at low advance ratio, such as take-off, than during gliding. © 2016. Published by The Company of Biologists Ltd.

An autonomous sperm-like propulsor in a quiescent flow

NASA Astrophysics Data System (ADS)

Kim, Boyoung; Park, Sung Goon; Sung, Hyung Jin

2016-11-01

Flapping motions of flexible fins are widespread in nature. Birds, fish, and insects use their wings, fins, or bodies to stay afloat and to advance forward in the surrounding fluids. It is important to understand the physics of the flapping motions to utilize them for the biomimetic machines. In the present study, we introduce a sperm-like propulsor that consists of a rigid head containing genetic information and a flapping flexible tail for propulsion. The head gives a sinusoidal torque to the leading edge of the tail, and the flexible tail flaps along the leading edge. In other words, the sperm-like propulsor is moved by an oscillating relative angle between the head and the leading edge of the tail. Unlike self-propelled heaving and pitching fins, the 'autonomous' sperm-like propulsor has no prescribed motion or constraint referenced from outside coordinates. The penalty method and the immersed boundary method are used to solve the autonomous sperm-like propulsor in a quiescent flow. The cruising speed and the propulsive efficiency of the propulsor are explored as a function of the head size (D/ L) , the pitching angle (θ0) , the pitching frequency (f) , and the distance from the wall (G/ L) .

Lateral stability and control tests of the XP-77 airplane in the NACA full-scale tunnel, 16 June 1944

NASA Technical Reports Server (NTRS)

Czarnecki, K. R.; Donlan, C. J.

1976-01-01

Tests were made in the NACA full-scale tunnel to determine the lateral stability and control characteristics of the XP-77 airplane. Measurements were made of the forces and moments on the airplane at various angles of attack and angles of yaw. The measurements were made with the propeller removed and with the propeller installed and operating at various thrust coefficients, and with the landing flaps retracted and deflected. The effects of aileron, elevator, and rudder deflection on control surface effectiveness and hinge moments were determined. The tests were planned to obtain the data required to evaluate as completely as possible the Army Air Force requirements on lateral stability and control for pursuit-type airplanes.

Studies in tilt-rotor VTOL aircraft aeroelasticity, volume 1. Ph.D. Thesis - Case Western Reserve Univ.

NASA Technical Reports Server (NTRS)

Kvaternik, R. G.

1973-01-01

Aeroelastic and dynamic studies which complement and extend various aspects of technology applicable to tilt-rotor VTOL aircraft are discussed. Particular attention is given to proprotor/pylon whirl instability, a precession-type instability akin to propeller/nacelle whirl flutter. The blade flapping and pitch-change freedoms of a proprotor are shown to lead to a fundamentally different situation as regards the manner in which the precession-generated aerodynamic forces and moments act on the pylon and induce whirl flutter relative to that of a propeller. The implication of these forces and moments with regard to their capacity for instigating a whirl instability is examined, demonstrating why a proprotor can exhibit whirl flutter in either the backward or forward directions in contrast to a propeller which is found to always whirl in the backward direction. Analytical trend studies delineating the effect of several system design parameters on proprotor/pylon stability and response are shown.

Pulsed hydrojet

DOEpatents

Bohachevsky, I.O.; Torrey, M.D.

1986-06-10

An underwater pulsed hydrojet propulsion system is provided for accelerating and propelling a projectile or other vessel. A reactant, such as lithium, is fluidized and injected into a water volume. The resulting reaction produces an energy density in a time effective to form a steam pocket. Thrust flaps or baffles direct the pressure from the steam pocket toward an exit nozzle for accelerating a water volume to create thrust. A control system regulates the dispersion of reactant to control thrust characteristics.

Advanced Concept Architecture Design and Integrated Analysis (ACADIA)

DTIC Science & Technology

2017-11-03

and the vertical drag due to the induced velocity download on the vehicle structure. The propeller blades are assumed to be rigid and therefore any...flapping of the blades is assumed to be negligible. Thus, the tip path plane angle of attack gives an indication of the multicopter attitude when used...The software required to run this printer is called Catalyst EX. Catalyst EX generates an estimated print time with a given STL file. Fixed wing

Wing high-lift system with spoiler droop

NASA Astrophysics Data System (ADS)

Gubsky, Vitaly; Pavlenko, Olga; Petrov, Albert

2018-05-01

Take-off and landing regimes are becoming increasingly difficult due to the increased aircraft mass and speed and the toughening of air safety demands. The capabilities of conventional single-slotted or multi-slotted flaps are limited. This problem can be resolved by the deflection or bending of the tail section, which forms a potential flow that results in an increase in the lift component at high angles of attack. Different versions of the flap on a two-part high-lift device with a spoiler are examined. Calculations show that the application of an adaptive high-lift system with spoiler droop to an aircraft increases the lift coefficient by as much as 15%. Aircraft model experiments indicated that a δs = 5° deflection of the trailing edge increases the lift coefficient by 11% - 13%. Setting the propeller load coefficient to B = 1 (thrust/velocity factor propeller area) under take-off δf = 20° and landing δf = 35° configurations increases the efficiency of a lift coefficient by 25% and 36%, respectively. The application of spoiler droop and leading edge modifications of the wing expands the operational range of angles of attack and increases the lift coefficient by 10% at a small intensity (B = 0.5). It is concluded that the application of spoiler droop to high-lift system allows improvement of the wing properties under take-off and landing regimes of various types.

Rotational accelerations stabilize leading edge vortices on revolving fly wings.

PubMed

Lentink, David; Dickinson, Michael H

2009-08-01

The aerodynamic performance of hovering insects is largely explained by the presence of a stably attached leading edge vortex (LEV) on top of their wings. Although LEVs have been visualized on real, physically modeled, and simulated insects, the physical mechanisms responsible for their stability are poorly understood. To gain fundamental insight into LEV stability on flapping fly wings we expressed the Navier-Stokes equations in a rotating frame of reference attached to the wing's surface. Using these equations we show that LEV dynamics on flapping wings are governed by three terms: angular, centripetal and Coriolis acceleration. Our analysis for hovering conditions shows that angular acceleration is proportional to the inverse of dimensionless stroke amplitude, whereas Coriolis and centripetal acceleration are proportional to the inverse of the Rossby number. Using a dynamically scaled robot model of a flapping fruit fly wing to systematically vary these dimensionless numbers, we determined which of the three accelerations mediate LEV stability. Our force measurements and flow visualizations indicate that the LEV is stabilized by the ;quasi-steady' centripetal and Coriolis accelerations that are present at low Rossby number and result from the propeller-like sweep of the wing. In contrast, the unsteady angular acceleration that results from the back and forth motion of a flapping wing does not appear to play a role in the stable attachment of the LEV. Angular acceleration is, however, critical for LEV integrity as we found it can mediate LEV spiral bursting, a high Reynolds number effect. Our analysis and experiments further suggest that the mechanism responsible for LEV stability is not dependent on Reynolds number, at least over the range most relevant for insect flight (100

Hydrodynamics of a three-dimensional self-propelled flexible plate

NASA Astrophysics Data System (ADS)

Ryu, Jaeha; Sung, Hyung Jin

2017-11-01

A three-dimensional self-propelled flexible plate in a quiescent flow was simulated using the immersed boundary method. The clamped leading edge of the flexible plate was forced into a vertical oscillation, while free to move horizontally. To reveal the hydrodynamics of the plate, the averaged cruising speed (UC) , the input power (P) , and the swimming efficiency (η) were analyzed as a function of the bending rigidity (γ) and the flapping frequency (f) . The velocity field around the plate and the exerted force on the plate were demonstrated to find out the dynamic interaction between the plate and the surrounding fluid. The kinematics of the plate, the maximum angle of attack (ϕmax) , and the mean effective length (Leff) were examined accounting for the hydrodynamics of the self-propelled flexible plate. The vortical structures around the plate were visualized, and the influence of the tip vortex on the swimming efficiency was explored qualitatively and quantitatively. This work was supported by the Creative Research Initiatives (No. 2017-013369) program of the National Research Foundation of Korea (MSIP).

Facial artery musculomucosal flap for reconstruction of skull base defects: a cadaveric study.

PubMed

Xie, Liyue; Lavigne, François; Rahal, Akram; Moubayed, Sami Pierre; Ayad, Tareck

2013-08-01

Failure in skull base defects reconstruction following tumor resection can have serious consequences such as ascending meningitis and pneumocephaly. The nasoseptal flap showed a very low incidence of cerebrospinal fluid leak but is not always available. The superiorly pedicled facial artery musculomucosal (FAMM) flap has been successfully used for reconstruction of head and neck defects. Our objective is to show that the FAMM flap can be used as a new alternative in skull base reconstruction. Cadaveric study. Feasibility. Thirteen specimens underwent bilateral FAMM flap dissection. Two new modifications of the traditional FAMM flap have been developed. Feasibility in FAMM flap transfer to the skull base was investigated through endoscopic skull base dissection and maxillectomy in four specimens. Measurements were recorded for each harvested flap. The mean surface area of the modified FAMM flap efficient for reconstruction was 15.90 cm(2) . The flaps easily covered the simulated defects of the frontal sinus and the fovea ethmoidalis areas. Modifications of the traditional FAMM flap were necessary for a tension-free coverage of the planum sphenoidale and sella turcica. The FAMM flap holds high potential as a new alternative vascular flap in skull base reconstruction. However, it has not been used in patients yet and should be considered only when other options are not available. New modifications developed in this article can elongate the traditional FAMM flap, potentially contributing to a tighter seal of the skull base defect than FAMM flap alone. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Effects of an Air-Powder Abrasive Device When Used during Periodontal Flap Surgery in Dogs.

DTIC Science & Technology

1983-01-01

instru- ments, ultrasonic devices, air driven reciprocating hand- pieces, and air driven rotary handpieces (Schaffer, 1967). None of these techniques...system, the Prophy-Jet Mark IV C-100 , may be an alternative to conventional mechanical and chemical methods of detoxifying roots. The handpiece is...electric current and uses inlet air pressure of 65 to 100 p.s.i. and inlet water pressure of 25 to 60 p.s.i. The handpiece propels particles of the

Wind-Tunnel Tests of the 1/9-Scale Model of the Curtiss XP-62 Airplane with Various Vertical Tail Arrangements

NASA Technical Reports Server (NTRS)

Wallace, Arthur R.; Recant, I.G.

1943-01-01

The effect of various vertical tail arrangements upon the stability and control characteristics of an XP-62 fighter model was investigated. Rudder-free yaw characteristics with take-off power and flaps deflected were satisfactory after dorsal fin modifications. Directional stability was obtained with all modified vertical tails. Satisfactory rudder effectiveness resulted partly because the dual-rotation propellers produced no asymmetric yawing moments. Pedal forces in sideslips were undesirably large but may be easily reduced.

Fluid-Dynamics of Underwater Flight in Sea Butterflies: Analysis using Tomographic PIV

NASA Astrophysics Data System (ADS)

Adhikari, D.; Murphy, D. W.; Webster, D. R.; Yen, J.

2014-11-01

Sea butterflies, Limacina helicina, swim in sea water with a pair of gelatinous ``wings'' (or parapodia). Their unique propulsion mechanism has been hypothesized to consist of a combination of drag-based propulsion (rowing) and lift-based propulsion (flapping). Drag-based propulsion utilizes maximum drag on the wings during power stroke, followed by minimum drag during recovery stroke. Lift-based propulsion, in contrast, utilizes a pressure difference between the top and bottom of the wings. We present the 3D kinematics of a free-swimming sea butterfly and its induced volumetric velocity field using tomographic PIV. Both upstroke and downstroke motions propel the animal (1 - 3 mm) upward in a sawtooth-like trajectory with average speed of 5 - 15 mm/s (Re = 5 - 45) and roll the calcareous shell forwards-and-backwards at 4 - 5 Hz. The rolling motion effectively positions the wings such that they stroke downward during both the power and recovery strokes, hence inducing upward motion during both phases. A clap-and-fling mechanism is observed at the beginning of the flapping cycle. As the wings come into contact, the velocity of the organism is 2 mm/s. During fling motion, high (unsteady) lift causes the organism velocity to reach 35 mm/s. Separation vortices are observed during the fling motion, and vortices with an opposite sense of rotation form closer to the base of the wing due to the upward translation of the organism. The separation vortices shed into the wake, as the organism translates upward, in the form of separate vortex pairs.

Pedicled Extranasal Flaps in Skull Base Reconstruction

PubMed Central

Kim, Grace G.; Hang, Anna X.; Mitchell, Candace; Zanation, Adam M.

2013-01-01

Cerebrospinal fluid (CSF) leaks most commonly arise during or after skull base surgery, although they occasionally present spontaneously. Recent advances in the repair of CSF leaks have enabled endoscopic endonasal surgery to become the preferred option for management of skull base pathology. Small defects (<1cm) can be repaired by multilayered free grafts. For large defects (>3cm), pedicled vascular flaps are the repair method of choice, resulting in much lower rates of postoperative CSF leaks. The pedicled nasoseptal flap (NSF) constitutes the primary reconstructive option for the vast majority of skull base defects. It has a large area of potential coverage and high rates of success. However, preoperative planning is required to avoid sacrificing the NSF during resection. In cases where the NSF is unavailable, often due to tumor involvement of the septum or previous resection removing or compromising the flap, other flaps may be considered. These flaps include intranasal options—inferior turbinate (IT) or middle turbinate (MT) flaps—as well as regional pedicled flaps: pericranial flap (PCF), temporoparietal fascial flap (TPFF), or palatal flap (PF). More recently, novel alternatives such as the pedicled facial buccinator flap (FAB) and the pedicled occipital galeopericranial flap (OGP) have been added to the arsenal of options for skull base reconstruction. Characteristics of and appropriate uses for each flap are described. PMID:23257554

Refining the cross-finger flap: Considerations of flap insetting, aesthetics and donor site morbidity.

PubMed

Chong, Chew-Wei; Lin, Cheng-Hung; Lin, Yu-Te; Hsu, Chung-Chen; Chen, Shih-Heng

2018-04-01

We described a laterally based cross-finger flap for reconstruction of soft tissue defects in the fingers. This modification enables coverage of volar or dorsal soft tissue defects at the distal, middle or proximal phalanx. From March 2015 to January 2017, a total of 12 patients (13 fingers) underwent soft tissue reconstruction of the fingers with a laterally based cross-finger flap. The flap dimensions ranged from 13 ×7 mm to 43 ×13 mm. Eleven of the 13 flaps survived completely. The two flap failures were attributed to injuries in the donor fingers, rendering the blood supply of the flaps unreliable. All donor sites were closed primarily without the need for skin grafting, negating the problem of donor site morbidity that is associated with skin graft harvesting. The laterally based cross-finger flap is a versatile flap with less donor site morbidity and better aesthetics than a conventional cross-finger flap. We described the design of the flap, as well as the advantages and disadvantages, in doing a laterally based cross-finger flap. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Reconstruction Using Locoregional Flaps for Large Skull Base Defects.

PubMed

Hatano, Takaharu; Motomura, Hisashi; Ayabe, Shinobu

2015-06-01

We present a modified locoregional flap for the reconstruction of large anterior skull base defects that should be reconstructed with a free flap according to Yano's algorithm. No classification of skull base defects had been proposed for a long time. Yano et al suggested a new classification in 2012. The lb defect of Yano's classification extends horizontally from the cribriform plate to the orbital roof. According to Yano's algorithm for subsequent skull base reconstructive procedures, a lb defect should be reconstructed with a free flap such as an anterolateral thigh free flap or rectus abdominis myocutaneous free flap. However, our modified locoregional flap has also enabled reconstruction of lb defects. In this case series, we used a locoregional flap for lb defects. No major postoperative complications occurred. We present our modified locoregional flap that enables reconstruction of lb defects.

Effect of marking pens on femtosecond laser-assisted flap creation.

PubMed

Ide, Takeshi; Kymionis, George D; Abbey, Ashkan M; Yoo, Sonia H; Culbertson, William W; O'Brien, Terrence P

2009-06-01

To compare the ease of the flap lift after central corneal marking with 2 types of marking pens after femtosecond laser-assisted flap creation in laser in situ keratomileusis. Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. Porcine eyes were prepared for flap creation with a femtosecond laser (IntraLase). The eyes were assigned to 1 of 4 groups. After the femtosecond laser treatment, the difficulty of flap lifting the 4 groups was compared. Twelve porcine eyes, 3 in each group, were evaluated. In the 2 groups in which an oil-based pen was used, the corneal flap could not be lifted. In the 2 groups in which a water-based pen was used, the corneal flap was easily lifted. Oil-based ink may reduce the ability of the femtosecond laser to penetrate the cornea. The resultant corneal flap may require aggressive manipulation to be lifted. When used to mark the center of the cornea before flap creation, water-based ink provided greater ease of corneal flap lifting than oil-based ink. Because the marking is located over the center of the pupil, any alteration of the cornea in this area from aggressive flap lifting may result in substantial visual loss. Therefore, the use of an oil-based ink to mark the central cornea must be avoided to prevent traumatic irregularities of the flap stroma.

Tensor fascia lata flap versus tensor fascia lata perforator-based island flap for the coverage of extensive trochanteric pressure sores.

PubMed

Kim, Youn Hwan; Kim, Sang Wha; Kim, Jeong Tae; Kim, Chang Yeon

2013-06-01

Tensor fascia lata (TFL) musculocutaneous flaps often require a donor site graft when harvesting a large flap. However, a major drawback is that it also sacrifices the muscle. To overcome this disadvantage, we designed a TFL perforator-based island flap that was harvested from a site near the defect and involved transposition within 90 degrees without full isolation of the pedicles. We performed procedures on 17 musculocutaneous flaps and 23 perforator-based island flaps, and compared the outcomes of these surgeries. The overall complication rate was 27.5% (11 regions). There were 7 complications related to the musculocutaneous flaps and 4 complications related to the perforator flaps. Although there were no statistical differences between those groups, lower complication rates were associated with procedures involving perforator flaps. The TFL perforator procedure is a simple and fast operation that avoids sacrificing muscle. This decreases complication rates compared to true perforator flap techniques that require dissection around the perforator or pedicle.

The myocutaneous trapezius flap revisited: a treatment algorithm for optimal surgical outcomes based on 43 flap reconstructions.

PubMed

Can, Anil; Orgill, Dennis P; Dietmar Ulrich, J O; Mureau, Marc A M

2014-12-01

Because the vascular anatomy of the trapezius flap is highly variable, choosing the most appropriate flap type and design is essential to optimize outcomes and minimize postoperative complications. The aim of this study was to develop a surgical treatment algorithm for trapezius flap transfers. The medical files of all consecutive patients with a myocutaneous trapezius flap reconstruction of the head, neck, and upper back area treated at three different university medical centers between July 2001 and November 2012 were reviewed. There were 43 consecutive flaps performed in 38 patients with a mean follow-up time of 15 months (range, 1-48 months). Eleven patients had a mentosternal burn scar contracture (12 flaps), 12 patients (13 flaps) presented with cancer, and 15 patients (18 flaps) were suffering from chronic wounds due to failed previous reconstruction (n = 6), osteoradionecrosis (n = 1), chronic infection (n = 3), bronchopleural fistula (n = 3), and pressure sores (n = 2). The mean defect size was 152 cm(2). Sixteen flaps were based on the superficial cervical artery (SCA; type 2), 16 were based on the dorsal scapular artery (DSA; type 3), one was based on the intercostal arteries (type 4), and 10 flaps were based on both the DSA and SCA. Recipient-site complications requiring reoperation occurred in 16.3%, including one total flap failure (2.6%). The trapezius myocutaneous flap is a valuable option to reconstruct various head and neck and upper back defects. Based on our data, a surgical treatment algorithm was developed in an attempt to reduce variation in care and improve clinical outcomes. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Determination of the Stability and Control Characteristics of a Tailless All-Wing Airplane Model with Sweepback in the Langley Free-Flight Tunnel

NASA Technical Reports Server (NTRS)

Seacord, Charles L.; Campbell, John P.

1945-01-01

Force and flight tests were performance on an all-wing model with windmilling propellers. Tests were conducted with deflected and retracted flaps, with and without auxiliary vertical tail surfaces, and with different centers of gravity and trim coefficients. Results indicate serious reduction of stick-fixed longitudinal stability because of wing-tip stalling at high lift coefficient. Directional stability without vertical tail is undesirably low. Low effective dihedral should be maintained. Elevator and rudder control system is satisfactory.

"Reading man flap" design for reconstruction of circular infraorbital and malar skin defects.

PubMed

Seyhan, Tamer; Caglar, Baris

2008-11-01

Surgical complications such as lid retraction and ectropion from graft or flap scar contracture make reconstruction of skin defects in the malar and infraorbital regions challenging. A new flap design, the reading man flap, was used to overcome these problems. The Limberg and bilobed flap were compared with the reading man flap. The reading man flap consists mainly of a superiorly based quadrangular flap and an inferiorly based triangular flap. Malar and infraorbital circular skin defects measuring 14 x 14 to 40 x 40 mm were reconstructed with a reading man flap in 13 patients. The defects occurred after basal cell carcinoma in all patients. The Limberg flap, bilobed flap, and reading man flap were planned for same-sized defects on the abdominoplasty resection material. The results were compared in terms of total scar area, scar length, and total healthy skin area discarded. When comparing the 3 flap designs, the reading man flap was the most suitable flap in terms of total scar area and length. The reading man flap can be used to reconstruct malar and infraorbital circular defects with good cosmetic results and without creating any tractional forces to the eyelids.

System and Method for Modeling the Flow Performance Features of an Object

NASA Technical Reports Server (NTRS)

Jorgensen, Charles (Inventor); Ross, James (Inventor)

1997-01-01

The method and apparatus includes a neural network for generating a model of an object in a wind tunnel from performance data on the object. The network is trained from test input signals (e.g., leading edge flap position, trailing edge flap position, angle of attack, and other geometric configurations, and power settings) and test output signals (e.g., lift, drag, pitching moment, or other performance features). In one embodiment, the neural network training method employs a modified Levenberg-Marquardt optimization technique. The model can be generated 'real time' as wind tunnel testing proceeds. Once trained, the model is used to estimate performance features associated with the aircraft given geometric configuration and/or power setting input. The invention can also be applied in other similar static flow modeling applications in aerodynamics, hydrodynamics, fluid dynamics, and other such disciplines. For example, the static testing of cars, sails, and foils, propellers, keels, rudders, turbines, fins, and the like, in a wind tunnel, water trough, or other flowing medium.

Prevertebral corridor: posterior pathway for reconstruction of the ventral skull base.

PubMed

Durmaz, Abdullah; Fernandez-Miranda, Juan; Snyderman, Carl H; Rivera-Serrano, Carlos; Tosun, Fuat

2011-05-01

Regional vascularized flaps, such as the pericranial and temporoparietal fascia flaps, are currently used for reconstruction of skull base defects after endoscopic endonasal surgery whenever local vascularized flaps, such as the nasoseptal flap, are not available. Two different transposition pathways, infratemporal transpterygoid and subfrontal, have been proposed for regional flaps. The objective of this study was to describe and assess the feasibility of the transposition of a vascularized pedicled flap from the occipital galeopericranium via the prevertebral space corridor into the nasopharynx. Ten heads were injected with colored silicone. An endoscopic endonasal anterior craniofacial resection and panclival approach were performed in each specimen. The occipital flap was harvested using a previously described technique. The prevertebral corridor, extending from the neck to the nasopharynx, was dissected superficial to the paraspinal muscles. Computed tomography-based image guidance was used to assess the relationship between the corridor and adjacent neurovascular structures. Length of the corridor and pedicle and area of the donor flap were measured. The flap was harvested and successfully transposed into the nasopharynx using the proposed corridor in all studied specimens (10 heads, 20 sides). All flaps provided complete coverage of the skull base defects. The average length of the pedicle was 70.5 (SD, 6.5) mm, and the average length and width of the flap were 99.9 (SD, 14.6) mm and 59.3 (SD, 10.9) mm, respectively. The average length of the prevertebral corridor was 49.7 (SD, 4.8) mm. The occipital flap has favorable anatomic characteristics for use in skull base reconstruction. Transposition of the flap via the prevertebral corridor is a suitable option for vascularized reconstruction of expanded endonasal skull base defects when other local or regional flaps are not available. Additional clinical studies are necessary to define its role in endoscopic endonasal surgery.

Influence of Flap Thickness on Nipple Projection After Nipple Reconstruction Using a Modified Star Flap.

PubMed

Ishii, Naohiro; Ando, Jiro; Harao, Michiko; Takemae, Masaru; Kishi, Kazuo

2018-05-07

In nipple reconstruction, the width, length, and thickness of modified star flaps are concerns for long-term reconstructed nipple projection. However, the flap's projection has not been analyzed, based on its thickness. The aim of the present study was to investigate how flap thickness in a modified star flap influences the resulting reconstructed nipple and achieves an appropriate flap width in design. Sixty-three patients who underwent nipple reconstruction using a modified star flap following implant-based breast reconstruction between August 2014 and July 2016 were included in this case-controlled study. The length of laterally diverging flaps was 1.5 times their width. The thickness of each flap was measured using ultrasonography, and the average thickness was defined as the flap thickness. We investigated the correlation between the resulting reconstructed nipple and flap thickness, and the difference of the change in the reconstructed nipple projection after using a thin or thick flap. The average flap thickness was 3.8 ± 1.7 (range 2.5-6.0) mm. There was a significant, linear correlation between the flap thickness and resulting reconstructed nipple projection (β = 0.853, p < 0.01). Furthermore, the difference between the thin and thick flaps in the resulting reconstructed nipple projection was significant (p < 0.01). Measuring the flap thickness preoperatively may allow surgeons to achieve an appropriate flap width; otherwise, alternative methods for higher projection might be used. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Classification and Microvascular Flap Selection for Anterior Cranial Fossa Reconstruction.

PubMed

Vargo, James D; Przylecki, Wojciech; Camarata, Paul J; Andrews, Brian T

2018-05-18

 Microvascular reconstruction of the anterior cranial fossa (ACF) creates difficult challenges. Reconstructive goals and flap selection vary based on the defect location within the ACF. This study evaluates the feasibility and reliability of free tissue transfer for salvage reconstruction of low, middle, and high ACF defects.  A retrospective review was performed. Reconstructions were anatomically classified as low (anterior skull base), middle (frontal bar/sinus), and high (frontal bone/soft tissue). Subjects were evaluated based on pathologic indication and goal, type of flap used, and complications observed.  Eleven flaps in 10 subjects were identified and anatomic sites included: low ( n  = 5), middle ( n  = 3), and high ( n  = 3). Eight of 11 reconstructions utilized osteocutaneous flaps including the osteocutaneous radial forearm free flap (OCRFFF) ( n  = 7) and fibula ( n  = 1). Other reconstructions included a split calvarial graft wrapped within a temporoparietal fascia free flap ( n  = 1), latissimus myocutaneous flap ( n  = 1), and rectus abdominis myofascial flap ( n  = 1). All 11 flaps were successful without microvascular compromise. No complications were observed in the high and middle ACF defect groups. Two of five flaps in the low defect group using OCRFFF flaps failed to achieve surgical goals despite demonstrating healthy flaps upon re-exploration. Complications included persistent cerebrospinal fluid leak ( n  = 1) and pneumocephalus ( n  = 1), requiring flap repositioning in one subject and a second microvascular flap in the second subject to achieve surgical goals.  In our experience, osteocutaneous flaps (especially the OCRFFF) are preferred for complete autologous reconstruction of high and middle ACF defects. Low skull base defects are more difficult to reconstruct, and consideration of free muscle flaps (no bone) should be weighed as an option in this anatomic area. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Cracking the perfusion code?: Laser-assisted Indocyanine Green angiography and combined laser Doppler spectrophotometry for intraoperative evaluation of tissue perfusion in autologous breast reconstruction with DIEP or ms-TRAM flaps.

PubMed

Ludolph, Ingo; Arkudas, Andreas; Schmitz, Marweh; Boos, Anja M; Taeger, Christian D; Rother, Ulrich; Horch, Raymund E; Beier, Justus P

2016-10-01

The aim of this prospective study was to assess the correlation of flap perfusion analysis based on laser-assisted Indocyanine Green (ICG) angiography with combined laser Doppler spectrophotometry in autologous breast reconstruction using free DIEP/ms-TRAM flaps. Between February 2014 and July 2015, 35 free DIEP/ms-TRAM flaps were included in this study. Besides the clinical evaluation of flaps, intraoperative perfusion dynamics were assessed by means of laser-assisted ICG angiography and post-capillary oxygen saturation and relative haemoglobin content (rHb) using combined laser Doppler spectrophotometry. Correlation of the aforementioned parameters was analysed, as well as the impact on flap design and postoperative complications. Flap survival rate was 100%. There were no partial flap losses. In three cases, flap design was based on the angiography, contrary to clinical evaluation and spectrophotometry. The final decision on the inclusion of flap areas was based on the angiographic perfusion pattern. Angiography and spectrophotometry showed a correlation in most of the cases regarding tissue perfusion, post-capillary oxygen saturation and relative haemoglobin content. Laser-assisted ICG angiography is a useful tool for intraoperative evaluation of flap perfusion in autologous breast reconstruction with DIEP/ms-TRAM flaps, especially in decision making in cases where flap perfusion is not clearly assessable by clinical signs and exact determination of well-perfused flap margins is difficult to obtain. It provides an objective real-time analysis of flap perfusion, with high sensitivity for the detection of poorly perfused flap areas. Concerning the topographical mapping of well-perfused flap areas, laser-assisted angiography is superior to combined laser Doppler spectrophotometry. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Proximally pedicled medial plantar flap based on superficial venous system alone for venous drainage.

PubMed

Wright, Thomas C; Mossaad, Bassem M; Chummun, Shaheel; Khan, Umraz; Chapman, Thomas W L

2013-07-01

The proximally pedicled medial plantar flap is well described for coverage of wounds around the ankle and heel. This flap is usually based on the deep venae comitantes for venous drainage, with the superficial veins divided during dissection. Usually any disruption of the deep venous system of the flap would result in abandoning this choice of flap. Venous congestion is a recognised complication of medial plantar flaps. The patient described in this case report had a medial ankle defect with exposed bone, for which a proximally pedicled medial plantar flap was used. As we raised the flap, both venae comitantes of the medial planter artery were found to be disrupted. The flap was raised based on the superficial veins draining into the great saphenous, as the only system for venous drainage, with no evidence of venous congestion. The flap was successfully transposed into the defect and healed with no complications. The proximally pedicled medial plantar flap can safely rely on the superficial venous system alone for drainage. In addition, preserving the superficial veins minimise the risk of venous congestion in this flap. We recommend preservation of superficial venous system when possible. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Investigation of flow mechanism of a robotic fish swimming by using flow visualization synchronized with hydrodynamic force measurement

NASA Astrophysics Data System (ADS)

Tan, Guang-Kun; Shen, Gong-Xin; Huang, Shuo-Qiao; Su, Wen-Han; Ke, Yu

2007-11-01

When swimming in water by flapping its tail, a fish can overcome the drag from uniform flow and propel its body. The involved flow mechanism concerns 3-D and unsteady effects. This paper presents the investigation of the flow mechanism on the basis of a 3-D robotic fish model which has the typical geometry of body and tail with periodic flapping 2-freedom kinematical motion testing in the case of St = 0.78, Re = 6,600 and phase delay mode ( φ = -75°), in which may have a greater or maximum propulsion (without consideration of the optimal efficiency). Using a special technique of dye visualization which can clearly show vortex sheet and vortices in detail and using the inner 3-component force balance and cable supporting system with the phase-lock technique, the 3-D flow structure visualized in the wake of fish and the hydrodynamic force measurement were synchronized and obtained. Under the mentioned flapping parameters, we found the key flow structure and its evolution, a pair of complex 3-D chain-shape vortex (S-H vortex-rings, S1-H1 and S2-H2, and their legs L1 and L2) flow structures, which attach the leading edge and the trailing edge, then shed, move downstream and outwards and distribute two anti-symmetric staggering arrays along with the wake of the fish model in different phase stages during the flapping period. It is different with in the case of St = 0.25-0.35. Its typical flow structure and evolution are described and the results prove that they are different from the viewpoints based on the investigation of 2-D cases. For precision of the dynamic force measurement, in this paper it was provided with the method and techniques by subtracting the inertial forces and the forces induced by buoyancy and gravity effect in water, etc. from original data measured. The evolution of the synchronized measuring forces directly matching with the flow structure was also described in this paper.

Investigation of flow mechanism of a robotic fish swimming by using flow visualization synchronized with hydrodynamic force measurement

NASA Astrophysics Data System (ADS)

Tan, Guang-Kun; Shen, Gong-Xin; Huang, Shuo-Qiao; Su, Wen-Han; Ke, Yu

When swimming in water by flapping its tail, a fish can overcome the drag from uniform flow and propel its body. The involved flow mechanism concerns 3-D and unsteady effects. This paper presents the investigation of the flow mechanism on the basis of a 3-D robotic fish model which has the typical geometry of body and tail with periodic flapping 2-freedom kinematical motion testing in the case of St = 0.78, Re = 6,600 and phase delay mode (φ = - 75°), in which may have a greater or maximum propulsion (without consideration of the optimal efficiency). Using a special technique of dye visualization which can clearly show vortex sheet and vortices in detail and using the inner 3-component force balance and cable supporting system with the phase-lock technique, the 3-D flow structure visualized in the wake of fish and the hydrodynamic force measurement were synchronized and obtained. Under the mentioned flapping parameters, we found the key flow structure and its evolution, a pair of complex 3-D chain-shape vortex (S-H vortex-rings, S1 - H1 and S2 - H2, and their legs L1 and L2) flow structures, which attach the leading edge and the trailing edge, then shed, move downstream and outwards and distribute two antisymmetric staggering arrays along with the wake of the fish model in different phase stages during the flapping period. It is different with in the case of St = 0.25-0.35. Its typical flow structure and evolution are described and the results prove that they are different from the viewpoints based on the investigation of 2-D cases. For precision of the dynamic force measurement, in this paper it was provided with the method and techniques by subtracting the inertial forces and the forces induced by buoyancy and gravity effect in water, etc. from original data measured. The evolution of the synchronized measuring forces directly matching with the flow structure was also described in this paper.

Distally based posterior interosseous flap: primary role in soft-tissue reconstruction of the hand.

PubMed

Agir, Hakan; Sen, Cenk; Alagöz, Sahin; Onyedi, Murat; Isil, Eda

2007-09-01

A series of 15 consecutive patients with various hand defects requiring flap coverage was reviewed in this study. The defects were all covered with the distally based posterior interosseous flap. Its main indications were in complex hand trauma, severe burn injury, or skin cancer ablation, either acute or postprimary. In 12 of the patients, flaps survived completely. In 3 patients, there was partial necrosis of the distal part of the flap, which did not require additional surgical procedure. Radial nerve palsy was noted in one of the cases, with a complete recovery after 3 months. Donor site was closed directly in up to 4-cm-wide flaps, while larger flaps required skin grafting. No major anatomic variation was observed. Distally based posterior interosseous flap is a reliable choice for various types and areas of hand defects, with very low donor-site morbidity, and should be more commonly considered in clinical practice.

The midline-based nasolabial transposition (MNT) flap: an original single-stage technique for nasal tip reconstruction.

PubMed

Beustes-Stefanelli, Matthieu; O'Toole, Greg; Schertenleib, Pierre

2015-04-01

Nasolabial flaps based on the lateral side of the nose for the reconstruction of lateral nasal defects in a single-stage procedure have been described. Similarly, in midline defects, nasolabial flaps can be used but a 2-stage procedure is classically required. The Midline-based Nasolabial Transposition (MNT) flap is presented as a new single-stage procedure for nasal tip reconstruction. Between 2009 and 2011, an MNT flap was used as a single-stage procedure in 3 cases of large nasal defects of the tip where the forehead flap was either contraindicated or rejected as an option by the patient. There were no complications and a satisfactory aesthetic result was achieved in all cases. The MNT flap is a new single-stage procedure for large nasal tip defects and as such represents an interesting alternative to the classical 2-stage forehead and nasolabial flaps, especially in elderly patients.

A systematic review of complication and recurrence rates of musculocutaneous, fasciocutaneous, and perforator-based flaps for treatment of pressure sores.

PubMed

Sameem, Mojib; Au, Michael; Wood, Thomas; Farrokhyar, Forough; Mahoney, James

2012-07-01

Management of pressure sores poses a significant reconstructive challenge for plastic surgeons. Currently, there is no consensus on whether musculocutaneous, fasciocutaneous, or perforator-based flaps provide superior results for treating pressure sores. The following databases were searched: Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, LILACS (January of 1950 to November of 2010), MEDLINE (January of 1950 to November of 2010), and EMBASE (January of 1980 to November of 2010). Only articles reporting on the use of musculocutaneous, fasciocutaneous, and perforator-based flaps were included. The primary study outcomes were complication and recurrence rates. Fifty-five articles were included in the final analysis (kappa = 0.78). From this total, 28 were categorized as pertaining to musculocutaneous flaps, 13 studied fasciocutaneous flaps, and 14 evaluated perforator-based flaps. The authors' review revealed recurrence and complication rates of 8.9 and 18.6 percent, respectively, following reconstruction with musculocutaneous flaps, 11.2 and 11.7 percent following reconstruction with fasciocutaneous flaps, and 5.6 and 19.6 percent following reconstruction with perforator-based flaps. Overall, statistical analysis revealed no significant difference in complication or recurrence rates among these three techniques. The authors' review revealed that there was no statistically significant difference with regard to recurrence or complication rates among musculocutaneous, fasciocutaneous, or perforator-based flaps. This suggests that surgeons performing such reconstructive procedures may choose to consider the advantages of a specific approach rather than the complication and recurrence rates. Therapeutic, IV.

Ontogeny of lift and drag production in ground birds.

PubMed

Heers, Ashley M; Tobalske, Bret W; Dial, Kenneth P

2011-03-01

The juvenile period is often a crucial interval for selective pressure on locomotor ability. Although flight is central to avian biology, little is known about factors that limit flight performance during development. To improve understanding of flight ontogeny, we used a propeller (revolving wing) model to test how wing shape and feather structure influence aerodynamic performance during development in the precocial chukar partridge (Alectoris chukar, 4 to >100 days post hatching). We spun wings in mid-downstroke posture and measured lift (L) and drag (D) using a force plate upon which the propeller assembly was mounted. Our findings demonstrate a clear relationship between feather morphology and aerodynamic performance. Independent of size and velocity, older wings with stiffer and more asymmetrical feathers, high numbers of barbicels and a high degree of overlap between barbules generate greater L and L:D ratios than younger wings with flexible, relatively symmetrical and less cohesive feathers. The gradual transition from immature feathers and drag-based performance to more mature feathers and lift-based performance appears to coincide with ontogenetic transitions in locomotor capacity. Younger birds engage in behaviors that require little aerodynamic force and that allow D to contribute to weight support, whereas older birds may expand their behavioral repertoire by flapping with higher tip velocities and generating greater L. Incipient wings are, therefore, uniquely but immediately functional and provide flight-incapable juveniles with access to three-dimensional environments and refugia. Such access may have conferred selective advantages to theropods with protowings during the evolution of avian flight.

Altitude Cooling Investigation of the R-2800-21 Engine in the P-47G Airplane. IV - Engine Cooling-Air Pressure Distribution

NASA Technical Reports Server (NTRS)

Kaufman, Samuel J.; Staudt, Robert C.; Valerino, Michael F.

1947-01-01

A study of the data obtained in a flight investigation of an R-2800-21 engine in a P-47G airplane was made to determine the effect of the flight variables on the engine cooling-air pressure distribution. The investigation consisted of level flights at altitudes from 5000 to 35,000 feet for the normal range of engine and airplane operation. The data showed that the average engine front pressures ranged from 0.73 to 0.82 of the impact pressure (velocity head). The average engine rear pressures ranged from 0.50 to 0.55 of the impact pressure for closed cowl flaps and from 0.10 to 0.20 for full-open cowl flaps. In general, the highest front pressures were obtained at the bottom of the engine. The rear pressures for the rear-row cylinders were .lower and the pressure drops correspondingly higher than for the front-row cylinders. The rear-pressure distribution was materially affected by cowl-flap position in that the differences between the rear pressures of the front-row and rear-row cylinders markedly increased as the cowl flaps were opened. For full-open cowl flaps, the pressure drops across the rear-row cylinders were in the order of 0.2 of the impact pressure greater than across the front-row cylinders. Propeller speed and altitude had little effect on the -coolingair pressure distribution, Increase in angle of inclination of the thrust axis decreased the front ?pressures for the cylinders at the top of the engine and increased them for the cylinders at the bottom of the engine. As more auxiliary air was taken from the engine cowling, the front pressures and, to a lesser extent, the rear pressures for the cylinders at the bottom of the engine decreased. No correlation existed between the cooling-air pressure-drop distribution and the cylinder-temperature distribution.

The Pacman Perforator-Based V-Y Advancement Flap for Reconstruction of Pressure Sores at Different Locations.

PubMed

Bonomi, Stefano; Salval, André; Brenta, Federica; Rapisarda, Vincenzo; Settembrini, Fernanda

2016-09-01

Many procedures have been proposed for the treatment of pressure sores, and V-Y advancement flaps are widely used to repair a defect. Unfortunately, the degree of mobility of a V-Y advancement flap is dependent on the laxity of the underlying subcutaneous tissue. This is an important disadvantage of traditional V-Y advancement flap and limits its use.We used V-Y advancement flaps as perforator-based to overcome mobility restriction problem, with a further modification (Pacman-like shape) to improve the covering surface area of the flap. Between January 2012 and December 2014, the authors used 37 V-Y Pacman perforator-based flaps in 33 consecutive patients for coverage of defects located at sacral (n = 21), ischial (n = 13), trochanter (n = 1) regions. There were 27 male and 6 female patients with a mean age of 49.9 years (range, 15-74 years). All flaps survived completely (92.3%) except 3 in which one of them had undergone total necrosis due to hematoma and the other 2 had partial necrosis. No venous congestion was observed. The mean follow-up period was 14.9 months (range, 2-38 months). No flap surgery-related mortality or recurrence of pressure sores was noted. The V-Y Pacman perforator-based advancement flaps are safe and very effective for reconstruction of pressure sores at various regions. The advantage of our modification procedure include shorter operative time, lesser pedicle dissection, low donor site morbidity, good preservation of muscle, and offers remarkable excursion to the V-Y flap, which make the V-Y Pacman perforator-based flaps an excellent choice for large pressure sore coverage.

Porcine experimental model for perforator flap raising in reconstructive microsurgery.

PubMed

González-García, José A; Chiesa-Estomba, Carlos M; Álvarez, Leire; Altuna, Xabier; García-Iza, Leire; Thomas, Izaskun; Sistiaga, Jon A; Larruscain, Ekhiñe

2018-07-01

Perforator free flap-based reconstruction of the head and neck is a challenging surgical procedure and needs a steep learning curve. A reproducible mammal large animal model with similarities to human anatomy is relevant for perforator flap raising and microanastomosis. The aim of this study was to assess the feasibility of a swine model for perforator-based free flaps in reconstructive microsurgery. Eleven procedures were performed under general anesthesia in a porcine model, elevating a skin flap vascularized by perforating musculocutaneous branches of the superior epigastric artery to evaluate the relevance of this model for head and neck reconstructive microsurgery. The anterior abdominal skin perforator-based free flap in a swine model irrigated by the superior epigastric artery was elevated in eleven procedures. In six of these procedures, we could perform an arterial and venous microanastomosis to the great vessels located in the base of the neck. The porcine experimental model of superior epigastric artery perforator-based free flap reconstruction offers relevant similarities to the human deep inferior epigastric artery perforator flap. We could demonstrate this model as acceptable for perforator free flap training due to the necessity of perforator and pedicle dissection and transfer to a distant area. Copyright © 2018 Elsevier Inc. All rights reserved.

Experimental study on thrust and power of flapping-wing system based on rack-pinion mechanism.

PubMed

Nguyen, Tuan Anh; Vu Phan, Hoang; Au, Thi Kim Loan; Park, Hoon Cheol

2016-06-20

This experimental study investigates the effect of three parameters: wing aspect ratio (AR), wing offset, and flapping frequency, on thrust generation and power consumption of a flapping-wing system based on a rack-pinion mechanism. The new flapping-wing system is simple but robust, and is able to create a large flapping amplitude. The thrust measured by a load cell reveals that for a given power, the flapping-wing system using a higher wing AR produces larger thrust and higher flapping frequency at the wing offset of 0.15[Formula: see text] or 0.20[Formula: see text] ([Formula: see text] is the mean chord) than other wing offsets. Of the three parameters, the flapping frequency plays a more significant role on thrust generation than either the wing AR or the wing offset. Based on the measured thrusts, an empirical equation for thrust prediction is suggested, as a function of wing area, flapping frequency, flapping angle, and wing AR. The difference between the predicted and measured thrusts was less than 7%, which proved that the empirical equation for thrust prediction is reasonable. On average, the measured power consumption to flap the wings shows that 46.5% of the input power is spent to produce aerodynamic forces, 14.0% to overcome inertia force, 9.5% to drive the rack-pinion-based flapping mechanism, and 30.0% is wasted as the power loss of the installed motor. From the power analysis, it is found that the wing with an AR of 2.25 using a wing offset of 0.20[Formula: see text] showed the optimal power loading in the flapping-wing system. In addition, the flapping frequency of 25 Hz is recommended as the optimal frequency of the current flapping-wing system for high efficiency, which was 48.3%, using a wing with an AR of 2.25 and a wing offset of 0.20[Formula: see text] in the proposed design.

Effect of topically applied minoxidil on the survival of rat dorsal skin flap.

PubMed

Gümüş, Nazım; Odemiş, Yusuf; Yılmaz, Sarper; Tuncer, Ersin

2012-12-01

Flap necrosis still is a challenging problem in reconstructive surgery that results in irreversible tissue loss. This study evaluated the effect of topically applied minoxidil on angiogenesis and survival of a caudally based dorsal rat skin flap. For this study, 24 male Wistar rats were randomly divided into three groups of eight each. A caudally based dorsal skin flap with the dimensions of 9 × 3 cm was raised. After elevation of the flaps, they were sutured back into their initial positions. In group 1 (control group), 1 ml of isotonic saline was applied topically to the flaps of all the animals for 14 days. In group 2, minoxidil solution was spread uniformly over the flap surface for 7 days after the flap elevation. In group 3, minoxidil solution was applied topically to the flap surface during a 14-day period. On day 7 after the flap elevation, the rats were killed. The average area of flap survival was determined for each rat. Subdermal vascular architecture and angiogenesis were evaluated under a light microscope after two full-thickness skin biopsy specimens had been obtained from the midline of the flaps. The lowest flap survival rate was observed in group 1, and no difference was observed between groups 1 and 2. Compared with groups 1 and 2, group 3 had a significantly increased percentage of flap survival (P < 0.05). Intense and moderate angiogenesis also was observed respectively at the proximal and distal areas of the flaps in group 3. The results of this experiment seem to show that the early effect of minoxidil is vasodilation and that prolonged use before flap elevation leads to angiogenesis, increasing flap viability. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Rate-determining Step of Flap Endonuclease 1 (FEN1) Reflects a Kinetic Bias against Long Flaps and Trinucleotide Repeat Sequences.

PubMed

Tarantino, Mary E; Bilotti, Katharina; Huang, Ji; Delaney, Sarah

2015-08-21

Flap endonuclease 1 (FEN1) is a structure-specific nuclease responsible for removing 5'-flaps formed during Okazaki fragment maturation and long patch base excision repair. In this work, we use rapid quench flow techniques to examine the rates of 5'-flap removal on DNA substrates of varying length and sequence. Of particular interest are flaps containing trinucleotide repeats (TNR), which have been proposed to affect FEN1 activity and cause genetic instability. We report that FEN1 processes substrates containing flaps of 30 nucleotides or fewer at comparable single-turnover rates. However, for flaps longer than 30 nucleotides, FEN1 kinetically discriminates substrates based on flap length and flap sequence. In particular, FEN1 removes flaps containing TNR sequences at a rate slower than mixed sequence flaps of the same length. Furthermore, multiple-turnover kinetic analysis reveals that the rate-determining step of FEN1 switches as a function of flap length from product release to chemistry (or a step prior to chemistry). These results provide a kinetic perspective on the role of FEN1 in DNA replication and repair and contribute to our understanding of FEN1 in mediating genetic instability of TNR sequences. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

The effect of topical minoxidil pretreatment on nonsurgical delay of rat cutaneous flaps: further studies.

PubMed

Gümüş, Nazım; Odemiş, Yusuf; Tuncer, Ersin; Yılmaz, Sarper

2013-08-01

The purpose of this study was to determine the effectiveness of topically applied minoxidil in the pharmacological delay phenomenon and to demonstrate the comparable microscopic and macroscopic changes between minoxidil-pretreated flaps and surgically delayed flaps. A modified version of the McFarlane flap was used. Group 1 rats, in which a caudally based dorsal skin flap was raised and sutured back, were the control group. In group II, minoxidil solution was spread over the marked skin flap area for 7 days. On the 7th day, a caudally based dorsal skin flap was elevated and then sutured back. Group III rats underwent a surgical delay procedure alone. On the 7th day after flap elevation, evaluation was done by histologic examination and calculation of the flap survival areas in all groups. The lowest flap survival rate appeared in group I and was statistically different from groups II and III. The mean surviving skin flap area in the minoxidil-pretreated group was significantly larger than that in the control group. After histologic evaluation, moderate angiogenesis was also detected in group II. We also found that surgical delay significantly reduced flap necrosis when compared to the minoxidil pretreatment group. According to our study, minoxidil may be considered an effective vasoactive agent for the stimulation of angiogenesis in rat cutaneous flaps and capable of achieving pharmacological delay and increasing flap survival. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Distally based sural neuro-fasciocutaneous perforator flap for foot and ankle reconstruction: Surgical modifications for flap pedicle and donor site closure without skin graft.

PubMed

Chi, Zhenglin; Chen, Yiheng; Chu, Tinggang; Gao, Weiyang; Li, Zhijie; Yan, Hede; Song, Yonghuan

2018-02-01

The conventional procedure of the sural neuro-fasciocutaneous flap enables the supply of blood and venous drainage by increasing the width of the adipofascial tissue and preserving tiny venous return routes. Moreover, skin graft is a common method for donor site closure, which may lead to some complications and influence the aesthetic appearance. We report modifications for a distally based sural neuro-fasciocutaneous perforator flap and a relaying flap for donor site closure without skin graft. Twelve patients undergoing the modified flap for foot and ankle reconstruction were included in this study between 2014 and 2016. A peroneal-based perforator, a superficial vein, and the vascular axis of the sural nerve were included in the pedicle. A Z-shape skin incision was performed to explore the perforator vessels and a relaying island perforator flap was used to close the donor site. All flaps survived completely without necrosis. The area of the flaps ranged from 16 × 8 cm to 30 × 15 cm. The diameter width of the pedicle ranged from 1.0 to 2.0 cm. A relaying perforator island flap was used in 10 cases for donor site closure and no skin graft was performed. There were no serious donor site complications. All patients were satisfied with the aesthetic outcome postoperatively at the final follow-up. The distally based sural neuro-fasciocutaneous perforator flap is considered a reliable method for foot and ankle reconstruction. The modification for flap pedicle and donor site closure method without skin graft should be recommended. Copyright © 2017. Published by Elsevier Ltd.

Impact of different antithrombotics on the microcirculation and viability of perforator-based ischaemic skin flaps in a small animal model.

PubMed

Fichter, Andreas M; Ritschl, Lucas M; Robitzky, Luisa K; Wagenpfeil, Stefan; Mitchell, David A; Wolff, Klaus-Dietrich; Mücke, Thomas

2016-10-21

The effects of antithrombotic drugs on random and free flap survival have been investigated in the past, but the experimental and clinical results are not in agreement. A perforator-based critical ischaemia model was used to evaluate the effects of different perioperatively administered pharmaceutical agents on tissue ischaemia and to assess the potential additional haemorheological or vasodilative effects of antithrombotics on flap microcirculation. Combined laser Doppler flowmetry and remission spectroscopy revealed an increase in certain microcirculation parameters in most groups in comparison with saline controls, and these changes correlated with flap survival. Clopidogrel and hirudin significantly improved the amount of viable flap tissue in comparison with controls, while unfractioned heparin had a negative effect on flap survival. Low molecular weight heparin, aspirin, pentoxifylline, and hydroxyethyl starch had no impact on the amount of viable flap tissue. A higher complication rate was observed in all experimental groups, but only clopidogrel had a negative impact on the flap viability. Our results add to the body of evidence supporting the conclusion that perioperative antithrombotic treatment improves flap survival. Clopidogrel and hirudin are effective pharmacological agents that significantly increased the viability of perforator-based skin flaps in rats, but at a higher risk of postoperative bleeding.

Superficial Circumflex Iliac Artery-Based Iliac Bone Flap Transfer for Reconstruction of Bony Defects.

PubMed

Yoshimatsu, Hidehiko; Iida, Takuya; Yamamoto, Takumi; Hayashi, Akitatsu

2018-05-12

 The superficial circumflex iliac artery (SCIA)-based iliac bone flap has yet to be widely used. The purpose of this article is to validate the feasibility of SCIA-based iliac bone flap transfers for reconstruction of small to moderate-sized bony defects. Retrospective outcome comparisons between SCIA-based iliac bone flaps and fibula flaps were made.  Twenty-six patients with bony tissue defects underwent reconstructions using either free SCIA-based iliac bone flaps (13) or fibula flaps (13). Outcomes were evaluated 9 months after the reconstruction on the following basis: bone length, pedicle length, skin paddle area, bone union, donor-site complications, skin paddle survival, and complications at the reconstructed site.  There was no statistically significant difference in pedicle length (iliac bone vs. fibula; 5.5 ± 1.8 vs. 4.1 ± 1.5 cm; p  = 0.181), in bone union rate (iliac bone vs. fibula; 100 vs 92.3%; p  = 0.308), in donor-site complication rate (iliac bone vs. fibula; 0 vs. 7.7%; p  = 0.308), or in skin paddle complete survival rate (iliac bone vs. fibula; 100 vs. 83.3%; p  = 0.125). Statistically significant differences were observed in bone flap length (iliac bone vs. fibula; 4.8 ± 2.2 vs. 11.1 ± 4.8 cm; p  = 0.0005), in skin paddle area (superficial circumflex iliac artery perforator flap vs. peroneal artery perforator flap; 58.8 ± 35.6 vs. 27.7 ± 17.5 cm 2 ; p  = 0.0343), and in reconstructed site complication rate (iliac bone vs. fibula; 0 vs. 30.8%; p  = 0.030).  In our series of SCIA-based iliac bone flap transfers, up to 8 × 3 cm could be procured along the iliac crest. When compared with fibula flap transfers, there were no significant statistical differences in pedicle length or in bone union rate; the SCIA-based iliac bone flap may be a feasible option for bony defects of small to moderate size. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Parasacral Perforator Flaps for Reconstruction of Sacral Pressure Sores.

PubMed

Lin, Chin-Ta; Chen, Shih-Yi; Chen, Shyi-Gen; Tzeng, Yuan-Sheng; Chang, Shun-Cheng

2015-07-01

Despite advances in reconstruction techniques, pressure sores continue to present a challenge to the plastic surgeon. The parasacral perforator flap is a reliable flap that preserves the entire contralateral side as a future donor site. On the ipsilateral side, the gluteal muscle itself is preserved and all flaps based on the inferior gluteal artery are still possible. We present our experience of using parasacral perforator flaps in reconstructing sacral defects. Between August 2004 and January 2013, 19 patients with sacral defects were included in this study. All the patients had undergone surgical reconstruction of sacral defects with a parasacral perforator flap. The patients' sex, age, cause of sacral defect, flap size, flap type, numbers of perforators used, rotation angle, postoperative complications, and hospital stay were recorded. There were 19 parasacral perforator flaps in this series. All flaps survived uneventfully except for 1 parasacral perforator flap, which failed because of methicillin-resistant Staphylococcus aureus infection. The overall flap survival rate was 95% (18/19). The mean follow-up period was 17.3 months (range, 2-24 months). The average length of hospital stay was 20.7 days (range, 9-48 days). No flap surgery-related mortality was found. Also, there was no recurrence of sacral pressure sores or infected pilonidal cysts during the follow-up period. Perforator-based flaps have become popular in modern reconstructive surgery because of low donor-site morbidity and good preservation of muscle. Parasacral perforator flaps are durable and reliable in reconstructing sacral defects. We recommend the parasacral perforator flap as a good choice for reconstructing sacral defects.

Instep island flaps.

PubMed

Reading, G

1984-12-01

The instep island flap is safe and useful. It is based on branches of the posterior tibial artery and can be a musculocutaneous or a direct fasciocutaneous island flap. Sensory branches of the digital nerves may be transposed with the flap. There is a wide arc of transposition and the flap has survived even in very difficult circumstances.

A lining vomer flap for palate pushback in unilateral cleft palate repair.

PubMed

Clavin, H D; Owsley, J Q

1978-01-01

A combinaation vomer mucoperiosteal flap and nasal floor mucoperiosteal flap is described which is used to achieve nasal coverage in unilateral cleft palate patients requiring pushbacks. A posteriorly based readily accessible vomer flap is raised on the cleft side and used as nasal lining for the palatal mucoperiosteal flap on the non-cleft side. On the cleft side, a symmetrically sized nasal floor flap is easily elevated under direct vision and used to cover the nasal aspect of the corresponding mucoperiosteal palatal flap.

Endoscopic endonasal double flap technique for reconstruction of large anterior skull base defects: technical note.

PubMed

Dolci, Ricardo Landini Lutaif; Todeschini, Alexandre Bossi; Santos, Américo Rubens Leite Dos; Lazarini, Paulo Roberto

2018-04-19

One of the main concerns in endoscopic endonasal approaches to the skull base has been the high incidence and morbidity associated with cerebrospinal fluid leaks. The introduction and routine use of vascularized flaps allowed a marked decrease in this complication followed by a great expansion in the indications and techniques used in endoscopic endonasal approaches, extending to defects from huge tumours and previously inaccessible areas of the skull base. Describe the technique of performing endoscopic double flap multi-layered reconstruction of the anterior skull base without craniotomy. Step by step description of the endoscopic double flap technique (nasoseptal and pericranial vascularized flaps and fascia lata free graft) as used and illustrated in two patients with an olfactory groove meningioma who underwent an endoscopic approach. Both patients achieved a gross total resection: subsequent reconstruction of the anterior skull base was performed with the nasoseptal and pericranial flaps onlay and a fascia lata free graft inlay. Both patients showed an excellent recovery, no signs of cerebrospinal fluid leak, meningitis, flap necrosis, chronic meningeal or sinonasal inflammation or cerebral herniation having developed. This endoscopic double flap technique we have described is a viable, versatile and safe option for anterior skull base reconstructions, decreasing the incidence of complications in endoscopic endonasal approaches. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Optimization design and dynamic analysis on the drive mechanisms of flapping-wing air vehicles based on flapping trajectories

NASA Astrophysics Data System (ADS)

Xie, Lingwang; Zhang, Xingwei; Luo, Pan; Huang, Panpan

2017-10-01

The optimization designs and dynamic analysis on the driving mechanism of flapping-wing air vehicles on base of flapping trajectory patterns is carried out in this study. Three different driving mechanisms which are spatial double crank-rocker, plane five-bar and gear-double slider, are systematically optimized and analysed by using the Mat lab and Adams software. After a series debugging on the parameter, the comparatively ideal flapping trajectories are obtained by the simulation of Adams. Present results indicate that different drive mechanisms output different flapping trajectories and have their unique characteristic. The spatial double crank-rocker mechanism can only output the arc flapping trajectory and it has the advantages of small volume, high flexibility and efficient space utilization. Both planar five-bar mechanism and gear-double slider mechanism can output the oval, figure of eight and double eight flapping trajectories. Nevertheless, the gear-double slider mechanism has the advantage of convenient parameter setting and better performance in output double eight flapping trajectory. This study can provide theoretical basis and helpful reference for the design of the drive mechanisms of flapping-wing air vehicles with different output flapping trajectories.

Lower Extremity Free Flaps for Breast Reconstruction.

PubMed

Dayan, Joseph H; Allen, Robert J

2017-11-01

Thigh-based flaps are typically a secondary option for breast reconstruction because of concerns regarding limited tissue volume and donor-site morbidity. In recent years, there have been a number of new techniques and insights that have resulted in greater flexibility and improved outcomes. This article reviews lessons learned from a large collective experience using the following 4 flaps: transverse upper gracilis also known as transverse myocutaneous gracilis, diagonal upper gracilis, profunda artery perforator, and lateral thigh perforator flaps. Flap selection considerations include the patient's fat distribution and skin laxity, perforator anatomy, and scar location. Pearls to minimize donor-site morbidity include avoiding major lymphatic collectors in the femoral triangle and along the greater saphenous vein and respecting the limits of flap dimension to reduce wound healing complications and distal ischemia. Limited flap volume may be addressed with stacking another flap from the contralateral thigh or primary fat grafting as opposed to overaggressive flap harvest from a single thigh. A detailed review of the benefits and disadvantages of each flap and strategies to improve results is discussed. With careful planning and selection, thigh-based flaps can provide a reliable option patients desiring autologous breast reconstruction.

[Pedicle flaps based on the sphenopalatine artery: anatomical and surgical study].

PubMed

Gras-Cabrerizo, Juan R; Gras-Albert, Juan R; Monjas-Canovas, Irene; García-Garrigós, Elena; Montserrat-Gili, Joan R; Sánchez del Campo, Francisco; Kolanczak, Katarzyna; Massegur-Solench, Humbert

2014-01-01

Local pedicle flaps based on the sphenopalatine artery make it possible to reconstruct large defects of the skull base (SB). From January 2008 to January 2013, 64 lesions with involvement of SB were analysed. These lesions were treated using endoscopic endonasal approach and required a pedicle flap based on the sphenopalatine artery. In addition, measurements and flexibility of the flaps were examined in 4 cadaveric nasal cavities. Surgical group. Sixty-four nasoseptal flaps (NSF) were used, in 4 cases associated with a middle turbinate flap (MTF), and in 1 case supplemented with an inferior turbinate flap (ITF). Five cerebrospinal fluid fistulas (8%) were noted. Among patients with initial lesions, 7% presented an anosmia. Cadaveric group. The length of the NSF varied between 5.2 cm and 7.7 cm and the width ranged from 3 cm to 4.5 cm. The ITF provided an anterior-posterior distance between 4.2 cm and 5 cm, with a width between 1.2 cm and 2.8 cm. The mean length of MTFs varied between 3.5 cm and 4.2 cm, with a width between 1.4 cm and 1.9 cm. The most versatile local flap for the reconstruction of skull base defects is the NSF, and flaps pedicled to the posterolateral nasal artery offer an excellent alternative. Copyright © 2013 Elsevier España, S.L. y Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

[Applied anatomy of the perforating branches artery and its distally-based flap of sural nerve nutrient vessels].

PubMed

Zhang, Fahui; Xie, Qiyang; Zheng, Heping

2005-07-01

To investigate the distribution of the perforating branches artery of distally-based flap of sural nerve nutrient vessels and its clinical application. The origins and distribution of perforating branches artery of distally-based flap were observed on specimens of 30 adult cadaveric low limbs by perfusing red gelatin to dissect the artery. Among the 36 cases, there were 21 males, 15 females. Their ages ranged from 6 to 66, 35. 2 in average. The defect area was 3.5 cm x 2.5 cm to 17.0 cm x 11.0 cm. The flap taken ranged from 4 cm x 3 cm to 18 cm x 12 cm. The perforating branches artery of distally-based flap had 2 to 5 branches and originated from the heel lateral artery, the terminal perforating branches of peroneal artery (diameters were 0.6+/-0.2 mm and 0.8+/-0.2 mm, 1.0 +/- 1.3 cm and 2.8 +/- 1.0 cm to the level of cusp lateral malleolus cusp). The intermuscular septum perforating branches of peroneal artery had 0 to 3 branches. Their rate of presence was 96.7%, 66.7% and 20.0% respectively (the diameters were 0.9 +/- 0.3, 1.0 +/- 0.2 and 0.8 +/- 0.4 mm, and their distances to the level of cusp of lateral malleolus were 5.3 +/- 2.1, 6.8 +/- 2.8 and 7.0 +/- 4.0 cm). Those perforating branches included fascia branches, cutaneous branches, nerve and vein nutrient branches. Those nutrient vessels formed longitudinal vessel chain of sural nerve shaft, vessel chain of vein side and vessel network of deep superficial fascia. The distally-based superficial sural artery island flap was used in 18 cases, all flaps survived. Distally-based sural nerve, small saphenous vein, and nutrient vessels of fascia skin have the same origin. Rotation point of flap is 3.0 cm to the cusp of lateral malleolus, when the distally-based flap is pedicled with the terminal branch of peroneal artery. Rotation point of flap is close to the cusp of lateral malleolus, when the distally-based flap is pedicled with the heel lateral artery.

Negative Pressure Wound Therapy Followed by Basic Fibroblast Growth Factor Spray as a Recovery Technique in Partial Necrosis of Distally Based Sural Flap for Calcaneal Osteomyelitis: A Case Report.

PubMed

Mikami, Taro; Kaida, Eriko; Yabuki, Yuichiro; Kitamura, Sho; Kokubo, Ken'ichi; Maegawa, Jiro

2018-03-28

The distally based sural flap is regarded as the first choice for reconstruction in the distal part of the lower leg because the flap is easy to raise, reliable in its blood supply, and prone to only a few complications. Limited data have investigated the details of treatment in cases of failure of distally based sural flaps. We report a case of calcaneal osteomyelitis in which a successful outcome was finally obtained with a partially necrosed, distally based sural flap using negative pressure wound therapy with basic fibroblast growth factor spray. The 2-year follow-up examination was uneventful. Moreover, the patient was able to walk freely with an ankle-foot orthosis in her house. This technique can be considered as a useful and effective option to recover unfavorable results of distally based sural flaps. Copyright © 2017 The American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Combined flaps based on the superficial temporal vascular system for reconstruction of facial defects.

PubMed

Zhou, Renpeng; Wang, Chen; Qian, Yunliang; Wang, Danru

2015-09-01

Facial defects are multicomponent deficiencies rather than simple soft-tissue defects. Based on different branches of the superficial temporal vascular system, various tissue components can be obtained to reconstruct facial defects individually. From January 2004 to December 2013, 31 patients underwent reconstruction of facial defects with composite flaps based on the superficial temporal vascular system. Twenty cases of nasal defects were repaired with skin and cartilage components, six cases of facial defects were treated with double island flaps of the skin and fascia, three patients underwent eyebrow and lower eyelid reconstruction with hairy and hairless flaps simultaneously, and two patients underwent soft-tissue repair with auricular combined flaps and cranial bone grafts. All flaps survived completely. Donor-site morbidity is minimal, closed primarily. Donor areas healed with acceptable cosmetic results. The final outcome was satisfactory. Combined flaps based on the superficial temporal vascular system are a useful and versatile option in facial soft-tissue reconstruction. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Perforator-based island flap with a peripheral muscle patch for coverage of sacral sores.

PubMed

Chang, Jung Woo; Lee, Jang Hyun; Choi, Matthew Seung Suk

2016-06-01

Despite numerous therapeutic advances, the treatment of pressure sores remains a challenge. The increased use of perforator flaps enables surgeons to minimize donor-site morbidity by sparing the underlying muscle. In the presence of focal deep spaces, however, the inclusion of muscle would be beneficial. The goal of this study was to introduce a method for including a muscle patch at the periphery of a perforator-based island flap for coverage of sacral pressure sores. Between March 2010 and February 2015, 26 patients with stage IV sacral sores underwent perforator-based island flap reconstruction with a peripheral muscle patch. Patient characteristics, including sex, age, defect size, and postoperative complications, were recorded. All flaps survived without major complications. No flap necrosis was noted. The present study shows that a muscle patch incorporated into the periphery of a perforator-based flap can be transferred safely. This can be a good surgical option in cases where infection control or more volume is needed. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Free-style dual plane recycling tensor fascia lata musculocutaneous perforator flap for reconstruction of recurrent trochanteric defects.

PubMed

Han, Ba Leun; Choi, Hwan Jun

2014-03-01

Sequential flap coverage might be required for recurrent defects, but reusing a flap as a donor site has seldom been reported. The concept of a "free-style flap" has been developed, and it allows reconstructive surgeons to raise flaps with various designs reliably, even at sites of previous flap surgery. This article presents the concept of free-style recycling of a tensor fascia lata flap into a perforator-based flap separated in 2 planes in a patient with a recurrent bilateral trochanteric defect. If a reliable perforator is preserved and identified within the tissues by computed tomography angiography or a Doppler device, a new perforator flap can be designed and raised at the previous flap site.

A reusable perforator-preserving gluteal artery-based rotation fasciocutaneous flap for pressure sore reconstruction.

PubMed

Lin, Pao-Yuan; Kuo, Yur-Ren; Tsai, Yun-Ta

2012-03-01

Perforator-based fasciocutaneous flaps for reconstructing pressure sores can achieve good functional results with acceptable donor site complications in the short-term. Recurrence is a difficult issue and a major concern in plastic surgery. In this study, we introduce a reusable perforator-preserving gluteal artery-based rotation flap for reconstruction of pressure sores, which can be also elevated from the same incision to accommodate pressure sore recurrence. The study included 23 men and 13 women with a mean age of 59.3 (range 24-89) years. There were 24 sacral ulcers, 11 ischial ulcers, and one trochanteric ulcer. The defects ranged in size from 4 × 3 to 12 × 10 cm(2) . Thirty-six consecutive pressure sore patients underwent gluteal artery-based rotation flap reconstruction. An inferior gluteal artery-based rotation fasciocutaneous flap was raised, and the superior gluteal artery perforator was preserved in sacral sores; alternatively, a superior gluteal artery-based rotation fasciocutaneous flap was elevated, and the inferior gluteal artery perforator was identified and dissected in ischial ulcers. The mean follow-up was 20.8 (range 0-30) months in this study. Complications included four cases of tip necrosis, three wound dehiscences, two recurrences reusing the same flap for pressure sore reconstruction, one seroma, and one patient who died on the fourth postoperative day. The complication rate was 20.8% for sacral ulcers, 54.5% for ischial wounds, and none for trochanteric ulcer. After secondary repair and reconstruction of the compromised wounds, all of the wounds healed uneventfully. The perforator-preserving gluteal artery-based rotation fasciocutaneous flap is a reliable, reusable flap that provides rich vascularity facilitating wound healing and accommodating the difficulties of pressure sore reconstruction. Copyright © 2011 Wiley Periodicals, Inc.

Distant Pedicle Flaps for Soft Tissue Coverage of Severely Burned Hands: An Old Idea Revisited

DTIC Science & Technology

2001-09-01

choice remains immedi- Fig. 2. Groin flap. Groin flap revision with liposuction . D.J. Barillo et al. / Burns 27 (2001) 613–619 617 Fig. 2. (Continued...to cover hand defects. Secondary liposuction procedures are effec- tive in debulking the flap. The Tensor Fascia Lata Flap (TFL) is based upon the

Sinonasal outcomes following endoscopic anterior skull base surgery with nasoseptal flap reconstruction: a prospective study.

PubMed

Hanson, M; Patel, P M; Betz, C; Olson, S; Panizza, B; Wallwork, B

2015-07-01

To assess nasal morbidity resulting from nasoseptal flap use in the repair of skull base defects in endoscopic anterior skull base surgery. Thirty-six patients awaiting endoscopic anterior skull base surgery were prospectively recruited. A nasoseptal flap was used for reconstruction in all cases. Patients were assessed pre-operatively and 90 days post-operatively via the Sino-Nasal Outcome Test 20 questionnaire and visual analogue scales for nasal obstruction, pain, secretions and smell; endoscopic examination findings and mucociliary clearance times were also recorded. Sino-Nasal Outcome Test 20 questionnaire data and visual analogue scale scores for pain, smell and secretions showed no significant differences between pre- and post-operative outcomes, with visual analogue scale scores for nasal obstruction actually showing a significant improvement (p = 0.0007). A significant deterioration for both flap and non-flap sides was demonstrated post-operatively on endoscopic examination (p = 0.002 and p = 0.02 respectively). Whilst elevation of a nasoseptal flap in endoscopic surgery of the anterior skull base engendered significant clinical deterioration on examination post-operatively, quality of life outcomes showed that no such deterioration was subjectively experienced by the patient. In fact, there was significant nasal airway improvement following nasoseptal flap reconstruction.

The inferior turbinate flap in skull base reconstruction

PubMed Central

2013-01-01

Background As the indications for expanded endonasal approaches continue to evolve, alternative reconstructive techniques are needed to address increasingly complex surgical skull base defects. In the absence of the nasoseptal flap, we describe our experience with the posterior pedicle inferior turbinate flap (PPITF) in skull base reconstruction. Design Case series. Setting Academic tertiary care centre. Methods Patients who underwent reconstruction of the skull base with the PPITF were identified. Medical records were reviewed for demographic, presentation, treatment, follow-up, surgical and outcomes data. Main outcome measures Flap survival, adequacy of seal, and complications. Results Two patients with residual/recurrent pituitary adenomas met the inclusion criteria. The nasoseptal flap was unavailable in each case due to a prior septectomy. Salvage of the original nasoseptal flap was not possible, as it did not provide adequate coverage of the resultant defect due to contraction from healing. All PPITFs healed uneventfully and covered the entire defect. No complications were observed in the early post-operative period. Endoscopic techniques and limitations of the PPITF are also discussed. Conclusions Our clinical experience supports the PPITF to be a viable alternative for reconstruction of the skull base in the absence of the nasoseptal flap. PMID:23663897

Flow interactions lead to orderly formations of flapping wings in forward flight

NASA Astrophysics Data System (ADS)

Ramananarivo, Sophie; Fang, Fang; Oza, Anand; Zhang, Jun; Ristroph, Leif

2016-11-01

Classic models of fish schools and flying formations of birds are built on the hypothesis that the preferred locations of an individual are determined by the flow left by its upstream neighbor. Lighthill posited that arrangements may in fact emerge passively from hydro- or aerodynamic interactions, drawing an analogy to the formation of crystals by intermolecular forces. Here, we carry out physical experiments aimed at testing the Lighthill conjecture and find that self-propelled flapping wings spontaneously assume one of multiple arrangements due to flow interactions. Wings in a tandem pair select the same forward speed, which tends to be faster than a single wing, while maintaining a separation distance that is an integer multiple of the wavelength traced out by each body. When perturbed, these locomotors robustly return to the same arrangement, and direct hydrodynamic force measurements reveal springlike restoring forces that maintain group cohesion. We also use these data to construct an interaction potential, showing how the observed positions of the follower correspond to stable wells in an energy landscape. Flow visualization and vortex-based theoretical models reveal coherent interactions in which the follower surfs on the periodic wake left by the leader. These results indicate that, for the high-Reynolds-number flows characteristic of schools and flocks, collective locomotion at enhanced speed and in orderly formations can emerge from flow interactions alone. If true for larger groups, then the view of collectives as ordered states of matter may prove to be a useful analogy.

Blood Perfusion in Human Eyelid Skin Flaps Examined by Laser Speckle Contrast Imaging-Importance of Flap Length and the Use of Diathermy.

PubMed

Nguyen, Cu Dinh; Hult, Jenny; Sheikh, Rafi; Tenland, Kajsa; Dahlstrand, Ulf; Lindstedt, Sandra; Malmsjö, Malin

2017-10-11

It is well known that blood perfusion is important for the survival of skin flaps. As no study has been conducted to investigate how the blood perfusion in human eyelid skin flaps is affected by the flap length and diathermy, the present study was carried out to investigate these in patients. Fifteen upper eyelids were dissected as part of a blepharoplastic procedure, releasing a 30-mm long piece of skin, while allowing the 5 mm wide distal part of the skin to remain attached, to mimic a skin flap (hereafter called a "skin flap"). Blood perfusion was measured before and after repeated diathermy, using laser speckle contrast imaging. Blood perfusion decreased from the base to the tip of the flap: 5 mm from the base, the perfusion was 69%, at 10 mm it was 40%, at 15 mm it was 20%, and at 20 mm it was only 13% of baseline values. Diathermy further decreased blood perfusion (measured 15 mm from the base) to 13% after applying diathermy for the first time, to 6% after the second and to 4% after the third applications of diathermy. Blood perfusion falls rapidly with distance from the base of skin flaps on the human eyelid, and diathermy reduces blood perfusion even further. Clinically, it may be advised that flaps with a width of 5 mm be no longer than 15 mm (i.e., a width:length ratio of 1:3), and that the use of diathermy should be carefully considered.

Perforator flap based on the third perforator of the profunda femoris artery (PFA)-assisted closure of the free vertical posteromedial thigh (vPMT) flap donor site.

PubMed

Scaglioni, Mario F; Barth, Andrè A; Chen, Yen-Chou

2018-06-19

The primary closure of the vertical posteromedial thigh (vPMT) free flap donor site is very important to minimize donor site morbidity and maximize cosmetic appearance. However, sometimes due to the dimension of the defect, a vPMT flap is wider than the 8-10 cm requirement. The authors report their experience with the third perforator of the profunda femoris artery (PFA) during the vPMT free flap donor-site closure. Between January 2016 and December 2017, 5 patients underwent reconstruction of lower extremity (2 pts.) and head and neck (3 pts.) area with the free vPMT flaps. Attempts to close the vPMT free flap donor site directly failed due to the flaps' width (average: 11 cm) and pedicled perforator flaps based on the third perforator of the PFA at the distal thigh were harvested to close the defect primary without the use of a skin graft. The size of perforator flap based on 3rd perforator of PFA was on average 6 cm × 4 cm (ranged: 4-8 cm × 3-6 cm). In all patients, the third perforator of the PFA was identified and the perforator diameter was on average 2.0 mm (range, 1.8-2.2 mm). All perforators were musculocutaneous and single. The dimensions of the flaps were on average 6 cm × 4 cm (range: 4 to 8 cm × 3 to 6 cm). All flaps healed uneventfully without complications and the patients were satisfied with cosmetic and functional results at 6 months follow-up. The third perforator of the PFA may be an option to ensure primary closure of the PMT flap donor site, when a larger flap for reconstruction is needed with subsequent impossibility to achieve primary closure of the donor site. © 2018 Wiley Periodicals, Inc.

Ontogeny of lift and drag production in ground birds

PubMed Central

Heers, Ashley M.; Tobalske, Bret W.; Dial, Kenneth P.

2011-01-01

The juvenile period is often a crucial interval for selective pressure on locomotor ability. Although flight is central to avian biology, little is known about factors that limit flight performance during development. To improve understanding of flight ontogeny, we used a propeller (revolving wing) model to test how wing shape and feather structure influence aerodynamic performance during development in the precocial chukar partridge (Alectoris chukar, 4 to >100 days post hatching). We spun wings in mid-downstroke posture and measured lift (L) and drag (D) using a force plate upon which the propeller assembly was mounted. Our findings demonstrate a clear relationship between feather morphology and aerodynamic performance. Independent of size and velocity, older wings with stiffer and more asymmetrical feathers, high numbers of barbicels and a high degree of overlap between barbules generate greater L and L:D ratios than younger wings with flexible, relatively symmetrical and less cohesive feathers. The gradual transition from immature feathers and drag-based performance to more mature feathers and lift-based performance appears to coincide with ontogenetic transitions in locomotor capacity. Younger birds engage in behaviors that require little aerodynamic force and that allow D to contribute to weight support, whereas older birds may expand their behavioral repertoire by flapping with higher tip velocities and generating greater L. Incipient wings are, therefore, uniquely but immediately functional and provide flight-incapable juveniles with access to three-dimensional environments and refugia. Such access may have conferred selective advantages to theropods with protowings during the evolution of avian flight. PMID:21307057

Extensive traumatic anterior skull base fractures with cerebrospinal fluid leak: classification and repair techniques using combined vascularized tissue flaps.

PubMed

Archer, Jacob B; Sun, Hai; Bonney, Phillip A; Zhao, Yan Daniel; Hiebert, Jared C; Sanclement, Jose A; Little, Andrew S; Sughrue, Michael E; Theodore, Nicholas; James, Jeffrey; Safavi-Abbasi, Sam

2016-03-01

This article introduces a classification scheme for extensive traumatic anterior skull base fracture to help stratify surgical treatment options. The authors describe their multilayer repair technique for cerebrospinal fluid (CSF) leak resulting from extensive anterior skull base fracture using a combination of laterally pediculated temporalis fascial-pericranial, nasoseptal-pericranial, and anterior pericranial flaps. Retrospective chart review identified patients treated surgically between January 2004 and May 2014 for anterior skull base fractures with CSF fistulas. All patients were treated with bifrontal craniotomy and received pedicled tissue flaps. Cases were classified according to the extent of fracture: Class I (frontal bone/sinus involvement only); Class II (extent of involvement to ethmoid cribriform plate); and Class III (extent of involvement to sphenoid bone/sinus). Surgical repair techniques were tailored to the types of fractures. Patients were assessed for CSF leak at follow-up. The Fisher exact test was applied to investigate whether the repair techniques were associated with persistent postoperative CSF leak. Forty-three patients were identified in this series. Thirty-seven (86%) were male. The patients' mean age was 33 years (range 11-79 years). The mean overall length of follow-up was 14 months (range 5-45 months). Six fractures were classified as Class I, 8 as Class II, and 29 as Class III. The anterior pericranial flap alone was used in 33 patients (77%). Multiple flaps were used in 10 patients (3 salvage) (28%)--1 with Class II and 9 with Class III fractures. Five (17%) of the 30 patients with Class II or III fractures who received only a single anterior pericranial flap had persistent CSF leak (p < 0.31). No CSF leak was found in patients who received multiple flaps. Although postoperative CSF leak occurred only in high-grade fractures with single anterior flap repair, this finding was not significant. Extensive anterior skull base fractures often require aggressive treatment to provide the greatest long-term functional and cosmetic benefits. Several vascularized tissue flaps can be used, either alone or in combination. Vascularized flaps are an ideal substrate for cranial base repair. Dual and triple flap techniques that combine the use of various anterior, lateral, and nasoseptal flaps allow for a comprehensive arsenal in multilayered skull base repair and salvage therapy for extensive and severe fractures.

Free-style puzzle flap: the concept of recycling a perforator flap.

PubMed

Feng, Kuan-Ming; Hsieh, Ching-Hua; Jeng, Seng-Feng

2013-02-01

Theoretically, a flap can be supplied by any perforator based on the angiosome theory. In this study, the technique of free-style perforator flap dissection was used to harvest a pedicled or free skin flap from a previous free flap for a second difficult reconstruction. The authors call this a free-style puzzle flap. For the past 3 years, the authors treated 13 patients in whom 12 pedicled free-style puzzle flaps were harvested from previous redundant free flaps and recycled to reconstruct soft-tissue defects at various anatomical locations. One free-style free puzzle flap was harvested from a previous anterolateral thigh flap for buccal cancer to reconstruct a foot defect. Total flap survival was attained in 12 of 13 flaps. One transferred flap failed completely. This patient had received postoperative radiotherapy after the initial cancer ablation and free anterolateral thigh flap reconstruction. Another free flap was used to close and reconstruct the wound. All the donor sites could be closed primarily. The free-style puzzle flap, harvested from a previous redundant free flap and used as a perforator flap to reconstruct a new defect, has proven to be versatile and reliable. When indicated, it is an alternative donor site for further reconstruction of soft-tissue defects.

Optimal placement of trailing-edge flaps for helicopter vibration reduction using response surface methods

NASA Astrophysics Data System (ADS)

Viswamurthy, S. R.; Ganguli, Ranjan

2007-03-01

This study aims to determine optimal locations of dual trailing-edge flaps to achieve minimum hub vibration levels in a helicopter, while incurring low penalty in terms of required trailing-edge flap control power. An aeroelastic analysis based on finite elements in space and time is used in conjunction with an optimal control algorithm to determine the flap time history for vibration minimization. The reduced hub vibration levels and required flap control power (due to flap motion) are the two objectives considered in this study and the flap locations along the blade are the design variables. It is found that second order polynomial response surfaces based on the central composite design of the theory of design of experiments describe both objectives adequately. Numerical studies for a four-bladed hingeless rotor show that both objectives are more sensitive to outboard flap location compared to the inboard flap location by an order of magnitude. Optimization results show a disjoint Pareto surface between the two objectives. Two interesting design points are obtained. The first design gives 77 percent vibration reduction from baseline conditions (no flap motion) with a 7 percent increase in flap power compared to the initial design. The second design yields 70 percent reduction in hub vibration with a 27 percent reduction in flap power from the initial design.

Early Reconstruction of Distal Leg and Foot in Acute High-Voltage Electrical Burn: Does Location of Pedicle in the Zone of Injury Affect the Outcome of Distally Based Sural Flap?

PubMed

Asʼadi, Kamran; Salehi, Seyed Hamid; Shoar, Saeed

2017-01-01

Distally based fasciocutaneous sural flap is popular in the reconstruction of distal leg and foot burns. However, utilization of this technique in high-voltage electrical injury has been challenging. The present study aimed to compare the outcome of early aggressive debridement and coverage of contact point of acute high-voltage electrical injury using distally based fasciocutaneous sural flap between high-risk and low-risk patients defined by the anatomic proximity of the flap pedicle to the zone of injury. A total of 51 patients with contact point of high-voltage electrical burn (HVEB) in distal leg and foot undergoing distally based fasciocutaneous sural flap were included in this prospective clinical study. In 28 patients, the flap pedicle was not involved in the contact point of high-voltage electrical injury (low risk/control group), whereas in 21 patients, it was located inside the zone of injury (high-risk/case group). Patients were followed up for a median of 21 months (range, 12-44 months). Wound dimensions to be covered were relatively similar between the 2 groups. Complications of flap survival (primary outcome) and other minor early and late complications (secondary outcome) did not significantly differ between the 2 groups (P > 0.05). Provided that early and completed debridements of contact points of HVEB were achieved, distally based sural flap is feasible and there is reliable coverage in HVEB even in patients with flap pedicle located in vicinity of the zone of injury.

Surgeon-Based 3D Printing for Microvascular Bone Flaps.

PubMed

Taylor, Erin M; Iorio, Matthew L

2017-07-01

Background  Three-dimensional (3D) printing has developed as a revolutionary technology with the capacity to design accurate physical models in preoperative planning. We present our experience in surgeon-based design of 3D models, using home 3D software and printing technology for use as an adjunct in vascularized bone transfer. Methods  Home 3D printing techniques were used in the design and execution of vascularized bone flap transfers to the upper extremity. Open source imaging software was used to convert preoperative computed tomography scans and create 3D models. These were printed in the surgeon's office as 3D models for the planned reconstruction. Vascularized bone flaps were designed intraoperatively based on the 3D printed models. Results  Three-dimensional models were created for intraoperative use in vascularized bone flaps, including (1) medial femoral trochlea (MFT) flap for scaphoid avascular necrosis and nonunion, (2) MFT flap for lunate avascular necrosis and nonunion, (3) medial femoral condyle (MFC) flap for wrist arthrodesis, and (4) free fibula osteocutaneous flap for distal radius septic nonunion. Templates based on the 3D models allowed for the precise and rapid contouring of well-vascularized bone flaps in situ, prior to ligating the donor pedicle. Conclusions  Surgeon-based 3D printing is a feasible, innovative technology that allows for the precise and rapid contouring of models that can be created in various configurations for pre- and intraoperative planning. The technology is easy to use, convenient, and highly economical as compared with traditional send-out manufacturing. Surgeon-based 3D printing is a useful adjunct in vascularized bone transfer. Level of Evidence  Level IV. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Single-stage interpolation flaps in facial reconstruction.

PubMed

Hollmig, S Tyler; Leach, Brian C; Cook, Joel

2014-09-01

Relatively deep and complex surgical defects, particularly when adjacent to or involving free margins, present significant reconstructive challenges. When the use of local flaps is precluded by native anatomic restrictions, interpolation flaps may be modified to address these difficult wounds in a single operative session. To provide a framework to approach difficult soft tissue defects arising near or involving free margins and to demonstrate appropriate design and execution of single-stage interpolation flaps for reconstruction of these wounds. Examination of our utilization of these flaps based on an anatomic region and surgical approach. A region-based demonstration of flap conceptualization, design, and execution is provided. Tunneled, transposed, and deepithelialized variations of single-stage interpolation flaps provide versatile options for reconstruction of a variety of defects encroaching on or involving free margins. The inherently robust vascularity of these flaps supports importation of necessary tissue bulk while allowing aggressive contouring to restore an intricate native topography. Critical flap design allows access to distant tissue reservoirs and placement of favorable incision lines while preserving the inherent advantages of a single operative procedure.

Quantitative analysis of skin flap blood flow in the rat using laser Doppler velocimetry.

PubMed Central

Marks, N J

1985-01-01

Two experiments carried out on rat skin flaps are described, where microvascular flow has been measured noninvasively by a laser Doppler velocimeter. Using this technique it is possible to define the limits of an axial pattern flap in terms of microvascular flow; this was found to increase when the flap is elevated. 'Random-pattern' perfusion is defined by a fall in flow. This recovers sequentially along the flap, and at a constant rate at all sites. A differential in microvascular perfusion is thus maintained along a random-pattern flap for at least the first postoperative week. In a second experiment it is shown that there appears to be a linear relationship between the reduction in skin blood flow in a random-pattern flap and the distance from the base at which the measurements are made. It is suggested that these data support the view that the blood flow in a skin flap recovers primarily from its base rather than via peripheral neovascularization, and that this is due to vascular collaterals opening within the flap rather than to a relaxation of sympathetic tone. PMID:3156992

Why Pteropods Flap Their Wings, Periodically Pitch Their Shell, and Swim in a Sawtooth-like Trajectory

NASA Astrophysics Data System (ADS)

Adhikari, D.; Webster, D. R.; Yen, J.

2016-02-01

Antarctic pteropods (Limacina helicina antarctica), which are currently threatened by ocean acidification, swim in seawater with a pair of gelatinous parapodia (or "wings") via a distinctive propulsion mechanism. By flapping their parapodia in a way that resembles insect flight, they exhibit a unique shell wobble (or periodic shell pitching) motion and sawtooth-like trajectory. We present three-dimensional kinematics and volumetric fluid velocity fields for upward-swimming pteropods. Time-resolved data were collected with a unique infrared tomographic particle image velocimetry (tomo-PIV) system that was transported to Palmer Station, Antarctica. Both power and recovery strokes of the parapodia propel the pteropod (1.5 - 5 mm in size) upward in a sawtooth-like trajectory with average speed of 14 - 30 mm/s and periodically pitch the shell at 1.9 - 3 Hz with up to 110° difference in pitching angle. The pitch motion effectively positions the parapodia such that they stroke downward during both the power and recovery strokes. We use the kinematics measurement to illustrate the relationship between flapping, swimming and pitching, where the corresponding Reynolds numbers (i.e. Ref, ReU, and ReΩ) characterize the motion of the pteropod. For example, when Ref < 50, the shell does not pitch and the pteropod swims abnormally with little or no vertical translation. We show that the flow field and vortices generated during pteropod propulsion resemble some aspects of insect-flight aerodynamics reported in classic literature, albeit with distinct aquatic variations.

The free descending branch muscle-sparing latissimus dorsi flap: vascular anatomy and clinical applications.

PubMed

Colohan, Shannon; Wong, Corrine; Lakhiani, Chrisovalantis; Cheng, Angela; Maia, Munique; Arbique, Gary; Saint-Cyr, Michel

2012-12-01

Increasing focus on reducing morbidity from latissimus dorsi flaps has led to the evolution of muscle-sparing variants and perforator-based flaps. This study aimed to investigate the vascular anatomy of the muscle-sparing variant and to describe its application as a free flap based on the descending branch of the thoracodorsal artery. Twelve fresh cadavers underwent anatomical dissection and angiographic injection studies of the thoracodorsal arterial system. The musculocutaneous territories of the descending and transverse branches to the latissimus dorsi muscle were identified and assessed using three-dimensional reconstruction software of computed tomography imaging results. In the clinical study, five patients underwent reconstruction of a variety of defects using the free descending branch muscle-sparing latissimus dorsi flap. Three- and four-dimensional (computed tomography) angiography demonstrated perfusion of the latissimus dorsi muscle by the transverse and descending branches, with overlap of vascular territories via cross-linking vessels. The descending branch supplied a slightly greater cutaneous area overlying the muscle, although differences between both branches were not significant (p = 0.76). In the clinical study, the free muscle-sparing latissimus dorsi flap provided excellent coverage with no flap complications or seroma. The free muscle-sparing latissimus dorsi flap based on the descending branch of the thoracodorsal artery is a viable reconstructive option. Significant collateral flow between vessels allows for larger flap harvest than would be expected. The flap is technically simple to harvest, provides a large perfusion area, and is a reliable variant of the full latissimus dorsi flap. Therapeutic, V.

Study of Flapping Flight Using Discrete Vortex Method Based Simulations

NASA Astrophysics Data System (ADS)

Devranjan, S.; Jalikop, Shreyas V.; Sreenivas, K. R.

2013-12-01

In recent times, research in the area of flapping flight has attracted renewed interest with an endeavor to use this mechanism in Micro Air vehicles (MAVs). For a sustained and high-endurance flight, having larger payload carrying capacity we need to identify a simple and efficient flapping-kinematics. In this paper, we have used flow visualizations and Discrete Vortex Method (DVM) based simulations for the study of flapping flight. Our results highlight that simple flapping kinematics with down-stroke period (tD) shorter than the upstroke period (tU) would produce a sustained lift. We have identified optimal asymmetry ratio (Ar = tD/tU), for which flapping-wings will produce maximum lift and find that introducing optimal wing flexibility will further enhances the lift.

Free anterolateral thigh flap for reconstruction of major craniofacial defects.

PubMed

Amin, Ayman; Rifaat, Mohammed; Civantos, Francisco; Weed, Donald; Abu-Sedira, Mohammed; Bassiouny, Mahmoud

2006-02-01

Free-tissue transfer has revolutionized skull-base surgery by expanding the ability to perform cranial base resection and by improving the quality of reconstruction. The anterolateral thigh flap has come recently into use in the field of head and neck reconstruction. Its role in craniofacial and midface reconstruction has not been specifically defined. This study involved a total of 18 patients who were treated over a 5-year period from 1998 to 2003. Seventeen patients had locally advanced head and neck cancer, requiring craniofacial resection, and one patient had a complicated gun shot wound of the forehead. Thirteen patients were treated at the National Cancer Institute, Cairo University, Egypt, and five patients at the University of Miami, Florida. The patients presented with defects of the anterior skull base (5), lateral skull base (3), scalp and calvarium (3), and the midface (7). The anterolateral thigh flap was used as a myocutaneous flap in 11 cases and as a perforator fasciocutaneous flap in seven cases. Musculocutaneous perforators supplied the majority of flaps (17/18). Total flap survival occurred in 17 cases; one patient developed complete flap necrosis. The most commonly used recipient vessels were the facial vessels and the external jugular vein. Major complications included one case with meningitis; the patient died after failure of treatment. Another patient died 6 weeks postoperatively from pulmonary embolism. One patient developed CSF leak that stopped spontaneously. In addition, two patients developed minor wound dehiscence that healed spontaneously. The donor-site wound healed without problems except in two cases. One patient had an incomplete take of the skin graft; the other developed wound infection and superficial sloughing. Both wounds healed spontaneously. In addition to the feasibility of simultaneous flap harvesting with tumor resection, the flap's advantage in skull base reconstruction is its reliable blood supply, which can provide adequate dural cover and protection of the brain. Its size and moderate thickness are suitable for reconstruction of scalp and calvarial defects. The abundance of reliably vascularized fat in the flap may be an advantage in long-term maintenance of the volume of the flap in midface reconstruction. Similar to other soft tissue flaps, additional skeletal reconstruction may still be required to achieve an optimal functional and aesthetic result.

Force-Test Investigation of the Stability and Control Characteristics of a 1/4-Scale Model of a Tilt-Wing Vertical-Take-Off-and-Landing Aircraft

NASA Technical Reports Server (NTRS)

Newsom, William A., Jr.; Tosti, Louis P.

1959-01-01

A wind-tunnel investigation has been made to determine the aerodynamic characteristics of a 1/4-scale model of a tilt-wing vertical-take-off-and-landing aircraft. The model had two 3-blade single-rotation propellers with hinged (flapping) blades mounted on the wing, which could be tilted from an incidence of 4 deg for forward flight to 86 deg for hovering flight. The investigation included measurements of both the longitudinal and lateral stability and control characteristics in both the normal forward flight and the transition ranges. Tests in the forward-flight condition were made for several values of thrust coefficient, and tests in the transition condition were made at several values of wing incidence with the power varied to cover a range of flight conditions from forward-acceleration (or climb) conditions to deceleration (or descent) conditions The control effectiveness of the all-movable horizontal tail, the ailerons and the differential propeller pitch control was also determined. The data are presented without analysis.

Efficacy of Liposuction as a Delay Method for Improving Flap Survival.

PubMed

Orhan, Erkan; Erol, Yağmur Reyyan; Deren, Orgun; Altun, Serdar; Erdoğan, Bülent

2016-12-01

Flaps are often used in repairing tissue defects and partial or full flap loss is still an important morbidity cause. Several techniques have been tried to increase flap circulation but none of these could replace the delay technique. Our goal in this study is to show the efficacy of liposuction in delay of dorsal rat cutaneous flaps and improvement in flap survival. Twenty-four Wistar rats were used. The rats in group 1 received 9 × 3-sized caudally-based random pattern skin flaps. In group 2, liposuction was done under the tissue island spotted as the flap and after 14 days, standard flap surgery was done. In group 3, surgical delay was done and after 14 days, standard flap surgery was done. In group 4, liposuction was done under the tissue island spotted as the flap and standard flap surgery was done right after the liposuction. The rate of necrotic tissue in group 3 (surgical delay; mean % 13.7) was less than the rate in group 2 (liposuction delay; mean % 15.1), although the difference was not statistically significant. The necrosis rates in group 3 (surgical delay) and group 2 (liposuction delay) were less than the rates in both group 1 (only flap; mean % 41.5) and group 4 (liposuction flap; mean % 40.0) and this difference was statistically significant (p < 0.0001). Liposuction can be an alternative to surgical delay as a less invasive method in the clinic. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

An experimental study of pressures on 60 deg Delta wings with leading edge vortex flaps

NASA Technical Reports Server (NTRS)

Marchman, J. F., III; Terry, J. E.; Donatelli, D. A.

1983-01-01

An experimental study was conducted in the Virginia Tech Stability Wind Tunnel to determine surface pressures over a 60 deg sweep delta wing with three vortex flap designs. Extensive pressure data was collected to provide a base data set for comparison with computational design codes and to allow a better understanding of the flow over vortex flaps. The results indicated that vortex flaps can be designed which will contain the leading edge vortex with no spillage onto the wing upper surface. However, the tests also showed that flaps designed without accounting for flap thickness will not be optimum and the result can be oversized flaps, early flap vortex reattachment and a second separation and vortex at the wing/flap hinge line.

The Postauricular Helix-based Adipodermal-pedicle Turnover (PHAT) Flap: An Original Single-Stage Technique for Antihelix and Scapha Reconstruction.

PubMed

Beustes-Stefanelli, Matthieu; O'Toole, Greg; Schertenleib, Pierre

2016-01-01

In reconstructing anterior defects of the ear, postauricular flaps represent a popular option. The pedicle of such transauricular flaps can be superior, inferior, medial, or lateral. The postauricular helix-based adipodermal-pedicle turnover (PHAT) flap is an original single-stage transauricular technique for defects of the antihelix and scapha. Its skin paddle is on the posterior aspect of the ear. Its lateral de-epithelialized pedicle in front of the helix allows for it to easily reach peripheral anterior defects. In cases in which the underlying cartilage is involved, the extended PHAT (ePHAT) flap allows for restoring the contours of the ear without a cartilage graft. Between 2009 and 2011, a PHAT flap was used in 5 cases of defects of the antihelix or the scapha after tumor resection, 3 of which are in an extended version (ePHAT flap). There were no complications and a satisfactory aesthetic result was achieved in all cases. The PHAT flap is an original single-stage procedure for anterior auricular defects located on the antihelix or scapha. The single-layer PHAT flap is indicated in purely skin defect. The triple-layer ePHAT flap includes two subcutaneous extensions which increase its thickness and is indicated to restore the ear contours when cartilage has been removed.

Levator alae nasi muscle V-Y island flap for nasal tip reconstruction.

PubMed

La Padula, Simone; Abbate, Vincenzo; Di Monta, Gianluca; Schonauer, Fabrizio

2017-03-01

Nasal tip reconstruction can be very challenging. It requires close attention to skin texture, colour and thickness matching, with the respect of the nasal aesthetic units and symmetry. Flaps are usually preferred to skin grafts where possible. Based on different donor areas, various flaps have been described for reconstruction of this region. Here we present a new V-Y myocutaneous island flap based on the levator alae nasi muscle (LAN muscle) blood supply. This flap may represent an alternative to the nasalis myocutaneous sliding V-Y flap previously described by Rybka. As its pivot point it is located more cranially than the nasalis flap, and it can advance more medially than the Rybka flap, with the possibility of covering larger defects of the nasal tip area, up to 1.8 cm in diameter. Over the past 5 years, 24 patients received nasal tip reconstruction with this flap following the resection of basal cell carcinomas. Good tip projection was maintained, and the aesthetic outcome was satisfactory, with well healed scars. We recommend this technique as an alternative to other flaps for nasal tip defects, especially if paramedian. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

New model of flap-gliding flight.

PubMed

Sachs, Gottfried

2015-07-21

A new modelling approach is presented for describing flap-gliding flight in birds and the associated mechanical energy cost of travelling. The new approach is based on the difference in the drag characteristics between flapping and non-flapping due to the drag increase caused by flapping. Thus, the possibility of a gliding flight phase, as it exists in flap-gliding flight, yields a performance advantage resulting from the decrease in the drag when compared with continuous flapping flight. Introducing an appropriate non-dimensionalization for the mathematical relations describing flap-gliding flight, results and findings of generally valid nature are derived. It is shown that there is an energy saving of flap-gliding flight in the entire speed range compared to continuous flapping flight. The energy saving reaches the highest level in the lower speed region. The travelling speed of flap-gliding flight is composed of the weighted average of the differing speeds in the flapping and gliding phases. Furthermore, the maximum range performance achievable with flap-gliding flight and the associated optimal travelling speed are determined. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of the cranial rectus abdominus muscle pedicle flap as a blood supply for the caudal superficial epigastric skin flap in dogs.

PubMed

Degner, D A; Walshaw, R; Arnoczky, S P; Smith, R J; Patterson, J S; Degner, L A; Hamaide, A; Rosenstein, D

1996-01-01

This study evaluates the cranial rectus abdominus muscle pedicle flap as the sole blood supply for the caudal superficial epigastric skin flap. This flap was composed of a cranially based rectus abdominus muscle pedicle flap that was attached to the caudal superficial epigastric island skin flap (including mammary glands 2 to 5) via the pudendoepigastric trunk. Selective angiography of the cranial epigastric artery in eight cadaver dogs proved that the arterial vasculature in the cranial rectus abdominus was contiguous with that in the caudal superficial epigastric skin flap. In the live dog study, three of six of the flaps failed because of venous insufficiency. Necrosis of mammary gland 2 occurred in two of six flaps. One of six flaps survived with the exception of the cranial most aspect of mammary gland 2. Angiography of the cranial epigastric artery proved that arterial blood supply to these flaps was intact. Histological evaluation of the failed flaps showed full-thickness necrosis of the skin and subcutaneous tissues, the presence of severe congestion, and venous thrombosis. Retrograde venous blood flow through the flap was inconsistent, and hence resulted in failure of this myocutaneous flap. Use of this flap for clinical wound reconstruction cannot be recommended.

Assessment of Tissue Perfusion Following Conventional Liposuction of Perforator-Based Abdominal Flaps

PubMed Central

Saçak, Bülent; Yalçın, Doğuş; Pilancı, Özgür; Tuncer, Fatma Betül; Çelebiler, Özhan

2017-01-01

Background The effect of liposuction on the perforators of the lower abdominal wall has been investigated in several studies. There are controversial results in the literature that have primarily demonstrated the number and patency of the perforators. The aim of this study was to determine the effect of liposuction on the perfusion of perforator-based abdominal flaps using a combined laser–Doppler spectrophotometer (O2C, Oxygen to See, LEA Medizintechnik). Methods Nine female patients undergoing classical abdominoplasty were included in the study. Perforators and the perfusion zones of the deep inferior epigastric artery flap were marked on the patient's abdominal wall. Flap perfusion was quantitatively assessed by measuring blood flow, velocity, capillary oxygen saturation, and relative amount of hemoglobin for each zone preoperatively, after tumescent solution infiltration, following elevation of the flap on a single perforator, and after deep and superficial liposuction, respectively. Results The measurements taken after elevation of the flap were not significantly different than measurements taken after the liposuction procedures. Conclusions The liposuction procedure does not significantly alter the perfusion of perforator-based abdominal flaps in the early period. The abdominal tissue discarded in a classic abdominoplasty operation can be raised as a perforator flap and has been demonstrated to be a unique model for clinical research. PMID:28352599

Large-Scale Skin Resurfacing of the Upper Extremity in Pediatric Patients Using a Pre-Expanded Intercostal Artery Perforator Flap.

PubMed

Wei, Jiao; Herrler, Tanja; Gu, Bin; Yang, Mei; Li, Qingfeng; Dai, Chuanchang; Xie, Feng

2018-05-01

The repair of extensive upper limb skin lesions in pediatric patients is extremely challenging due to substantial limitations of flap size and donor-site morbidity. We aimed to create an oversize preexpanded flap based on intercostal artery perforators for large-scale resurfacing of the upper extremity in children. Between March 2013 and August 2016, 11 patients underwent reconstructive treatment for extensive skin lesions in the upper extremity using a preexpanded intercostal artery perforator flap. Preoperatively, 2 to 4 candidate perforators were selected as potential pedicle vessels based on duplex ultrasound examination. After tissue expander implantation in the thoracodorsal area, regular saline injections were performed until the expanded flap was sufficient in size. Then, a pedicled flap was formed to resurface the skin lesion of the upper limb. The pedicles were transected 3 weeks after flap transfer. Flap survival, complications, and long-term outcome were evaluated. The average time of tissue expansion was 133 days with a mean final volume of 1713 mL. The thoracoabdominal flaps were based on 2 to 6 pedicles and used to resurface a mean skin defect area of 238 cm ranging from 180 to 357 cm. In all cases, primary donor-site closure was achieved. Marginal necrosis was seen in 5 cases. The reconstructed limbs showed satisfactory outcome in both aesthetic and functional aspects. The preexpanded intercostal artery perforator flap enables 1-block repair of extensive upper limb skin lesions. Due to limited donor-site morbidity and a pedicled technique, this resurfacing approach represents a useful tool especially in pediatric patients.

Dual-dermal-barrier fashion flaps for the treatment of sacral pressure sores.

PubMed

Hsiao, Yen-Chang; Chuang, Shiow-Shuh

2015-02-01

The sacral region is one of the most vulnerable sites for the development of pressure sores. Even when surgical reconstruction is performed, there is a high chance of recurrence. Therefore, the concept of dual-dermal-barrier fashion flaps for sacral pressure sore reconstruction was proposed. From September 2007 to June 2010, nine patients with grade IV sacral pressures were enrolled. Four patients received bilateral myocutaneous V-Y flaps, four patients received bilateral fasciocutaneous V-Y flaps, and one patient received bilateral rotation-advanced flaps for sacral pressure reconstruction. The flaps were designed based on the perforators of the superior gluteal artery in one patient's reconstructive procedure. All flaps' designs were based on dual-dermal-barrier fashion. The mean follow-up time was 16 months (range = 12-25). No recurrence was noted. Only one patient had a complication of mild dehiscence at the middle suture line, occurring 2 weeks after the reconstructive surgery. The dual-dermal fashion flaps are easily duplicated and versatile. The study has shown minimal morbidity and a reasonable outcome.

Rethinking the superficial inferior epigastric artery flap in breast reconstruction: Video demonstration of a rapid, reliable harvest technique.

PubMed

Buchel, Edward W; Dalke, Kimberly R; Hayakawa, Thomas Ej

2013-01-01

Abdominal-based autologous free tissue breast reconstruction has undergone significant changes over the past decade. The evolution has focused on limiting morbidity of the donor site. The transition from the transverse rectus abdominus muscle free flap to the muscle-sparing transverse rectus abdominus muscle free flap to the deep inferior epigastric artery perforator free flap has markedly improved abdominal-based autologous breast reconstruction. However, all of these flaps involve an incision through the anterior rectus fascia and potential damage of intercostal motor and sensory nerves. The superficial inferior epigastric artery flap (SIEA) reliably perfuses the ipsilateral hemiabdomen, yet does not violate the fascia or any motor nerves. As a result, the incidence of hernia, abdominal wall weakness and bulging is essentially eliminated. Nevertheless, use of the SIEA flap remains marginal. Vessel size, dissection difficulties and lack of understanding of the relevant anatomy have limited its acceptance. The present article describes a rapid, reliable and safe dissection technique with an algorithm for harvesting the SIEA flap in autologous breast reconstruction.

The Arterialized Facial Artery Musculo-Mucosal Island Flap for Post-Oncological Tongue Reconstruction.

PubMed

Moro, Alessandro; Saponaro, Gianmarco; Doneddu, Piero; Cervelli, Daniele; Pelo, Sandro; Gasparini, Giulio; Garagiola, Umberto; D'Amato, Giuseppe; Todaro, Mattia

2018-05-15

In 1992, Pribaz described the facial artery musculomucosal flap (FAMM), an axial musculomucosal flap based on the facial artery. The FAMM flap, a modification of the nasolabial and buccal mucosal flaps, is widely used in the reconstruction of defects in the oral cavity. Many modifications of this flap have been described in the literature. Here we aimed to explore the use of an arterialized tunnelized FAMM island flap (a-FAMMIF) for the reconstruction tongue defects after tumor resection. From January 2015 to December 2016, five cases of tongue cancer were selected for the use of arterialized FAMMIF flap to reconstruct defects after tumor resection. Reconstruction was successful in all cases, except one case of total flap necrosis; partial necrosis of the flap occurred in two patients, which were solved with medications. The authors consider the a-FAMMIF an unreliable flap in the reconstruction of tongue defects.The authors recommend avoiding tunneling and island modification when the vein is not included in the pedicle.

Perforator Flaps after Excision of Large Epidermal Cysts in the Buttocks

PubMed Central

Kim, Sang Wha; Yang, Seong Hyeok; Kim, Jeong Tae

2014-01-01

Background Epidermal cysts are commonly occurring masses usually less than 5 cm in diameter, but in predisposed patients, epidermal cysts can grow relatively large due to chronic infection. Methods From June 2002 to July 2010, 17 patients received 19 regional perforator-based island flaps to cover defects due to the excision of large epidermal cysts (diameter >5 cm) in the buttocks. Eight patients had diabetes, and seven had rheumatoid arthritis. The pedicles were not fully isolated to prevent spasms or twisting. Results All the flaps survived completely, except for one case with partial necrosis of the flap, which necessitated another perforator-based island flap for coverage. There were two cases of wound dehiscence, which were re-closed after meticulous debridement. There were no recurrences of the masses during follow-up periods of 8.1 months (range, 6-12 months). Conclusions In patients with large epidermal cysts and underlying medical disorders, regional perforator-based island flaps can be the solution to coverage of the defects after excision. PMID:24665422

Perforator chimerism for the reconstruction of complex defects: A new chimeric free flap classification system.

PubMed

Kim, Jeong Tae; Kim, Youn Hwan; Ghanem, Ali M

2015-11-01

Complex defects present structural and functional challenges to reconstructive surgeons. When compared to multiple free flaps or staged reconstruction, the use of chimeric flaps to reconstruct such defects have many advantages such as reduced number of operative procedures and donor site morbidity as well as preservation of recipient vessels. With increased popularity of perforator flaps, chimeric flaps' harvest and design has benefited from 'perforator concept' towards more versatile and better reconstruction solutions. This article discusses perforator based chimeric flaps and presents a practice based classification system that incorporates the perforator flap concept into "Perforator Chimerism". The authors analyzed a variety of chimeric patterns used in 31 consecutive cases to present illustrative case series and their new classification system. Accordingly, chimeric flaps are classified into four types. Type I: Classical Chimerism, Type II: Anastomotic Chimerism, Type III: Perforator Chimerism and Type IV Mixed Chimerism. Types I on specific source vessel anatomy whilst Type II requires microvascular anastomosis to create the chimeric reconstructive solution. Type III chimeric flaps utilizes the perforator concept to raise two components of tissues without microvascular anastomosis between them. Type IV chimeric flaps are mixed type flaps comprising any combination of Types I to III. Incorporation of the perforator concept in planning and designing chimeric flaps has allowed safe, effective and aesthetically superior reconstruction of complex defects. The new classification system aids reconstructive surgeons and trainees to understand chimeric flaps design, facilitating effective incorporation of this important reconstructive technique into the armamentarium of the reconstruction toolbox. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Whom should we SPY? A cost analysis of laser-assisted indocyanine green angiography in prevention of mastectomy skin flap necrosis during prosthesis-based breast reconstruction.

PubMed

Kanuri, Arjun; Liu, Allen S; Guo, Lifei

2014-04-01

Skin flap necrosis is the most common complication following prosthesis-based breast reconstruction. Many studies have reported on the efficacy of laser-assisted indocyanine green angiography (SPY Elite System) in detecting flap necrosis. A cost-effectiveness analysis of laser-assisted indocyanine green angiography is lacking. The authors performed a retrospective review of all consecutive immediate postmastectomy prosthesis-based reconstructions at the Brigham and Women's Hospital over a 7-year 10-month period. The rate of mastectomy skin flap necrosis and related implant loss was determined for the entire cohort and for the subgroups of patients at increased risk for developing this complication: smokers, obese patients, and patients with large breasts. Cost of treating implant loss and skin flap necrosis was calculated based on the average treatment courses and costs at the authors' institution. The cost of the SPY was obtained from LifeCell Corp. From January of 2004 through October of 2011, 79 of 710 prosthesis-based breast reconstructions (11.1 percent) developed mastectomy skin flap necrosis requiring excision and reclosure. Performing laser-assisted indocyanine green angiography on the entire cohort would result in an additional cost of $1537.30 per case of flap necrosis prevented. If laser-assisted indocyanine green angiography was performed on only these high-risk subgroups, the cost savings per case of flap necrosis prevented is $2098.80 for smokers, $5162.30 for patients with a body mass index greater than 30, and $1892.70 for patients with mastectomy weight greater than 800 g. Laser-assisted indocyanine green angiography is not cost-effective as a preventative measure for flap necrosis if used indiscriminately on all patients undergoing prosthesis-based breast reconstructions, but it is cost-effective for high-risk patients, such as smokers, obese patients, and patients with large breasts.

Chimeric anterolateral thigh free flap for reconstruction of complex cranio-orbito-facial defects after skull base cancers resection.

PubMed

Cherubino, Mario; Turri-Zanoni, Mario; Battaglia, Paolo; Giudice, Marco; Pellegatta, Igor; Tamborini, Federico; Maggiulli, Francesca; Guzzetti, Luca; Di Giovanna, Danilo; Bignami, Maurizio; Calati, Carolina; Castelnuovo, Paolo; Valdatta, Luigi

2017-01-01

Complex cranio-orbito-facial defects after skull base cancers resection entail a functional and esthetic reconstruction. The introduction of endoscopic assisted techniques for excision surgery with the advances in reconstructive surgery and anesthesiology allowed to improve the management of such critical patients. We report a series of chimeric anterolateral thigh (ALT) flaps used to reconstruct complex cranio-orbital-facial defects after skull base surgery. A retrospective review of patients that underwent cranio-orbito-facial reconstruction using a chimeric ALT flap from March 2013 to October 2015 at a single tertiary care referral Institute was performed. All patients were affected by locally-advanced malignant tumor and the resulting defects involved the skull base in all cases. The ALT flaps were perforator-based flaps with different components: fascia, skin and muscle. The different flap territories had independent vascular supply and were independent of any physical interconnection except where linked by a common source vessel. Ten patients were included in the study. Three patients underwent adjuvant radiotherapy and to chemotherapy. The mean hospitalization time was 21 days (range, 8-24 days). One failure was observed. After a mean follow-up of 12.4 months, 3 patients died of the disease, 2 are alive with disease, while 5 patients (50%) are currently alive without evidence of disease. Chimeric ALT flap is a reliable and versatile reconstructive option for complex cranio-orbito-facial defects resulting from skull base surgery. The chimeric flap composed of different territories proved to be adequate for a patient-tailored three-dimensional reconstruction of the defects as well as able to resist to the postoperative adjuvant treatments. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Bolstering the Nasoseptal Flap Using Sphenoid Sinus Fat Packing: A Technical Case Report.

PubMed

Abou-Al-Shaar, Hussam; Zaidi, Hasan A; Cote, David J; Laws, Edward R

2017-03-01

Resection of extensive skull base lesions often necessitates relatively large dural openings and arachnoid, resulting in skull base defects with the potential for a postoperative cerebrospinal fluid leak. A nasoseptal flap (NSF) is a vascularized graft that has greatly diminished the incidence of cerebrospinal fluid leak. Annealing of flaps against the ventral skull base can be tenuous within the first few days after surgery. We report the use of sphenoid sinus fat packing as a buttress to support the nasoseptal flap during skull base reconstruction. A 37-year-old man presented with pan-hypopituitarism, bitemporal hemianopsia, and imaging consistent with a craniopharyngioma. He underwent an endoscopic endonasal approach with resection of the planum and tuberculum sphenoidale for resection of this mass. An NSF was harvested, and a combination of suprasellar fat packing, tensor fasciae lata graft, and Porex plate along with the flap were used to reconstruct the skull base. Postoperatively, he precipitously experienced copious rhinorrhea necessitating surgical re-exploration. A redundant segment of the NSF had retracted into the sphenoid sinus, and was no longer supported against the ventral skull base. We repositioned the NSF and used sphenoid sinus fat packing to help support the graft against the ventral skull base. A postoperative computed tomographic scan demonstrated a clear delineation between the vascularized graft and the fat packing, confirming proper positioning of the flap. Sphenoid sinus fat packing can be an important technical adjunct in bolstering the nasoseptal flap against the ventral skull base in the tenuous early perioperative period. Copyright © 2016 Elsevier Inc. All rights reserved.

Reconstruction of palatal defect using mucoperiosteal hinge flap and pushback palatoplasty.

PubMed

Lee, S I; Lee, H S; Hwang, K

2001-11-01

This article describes a simple, new surgical technique to provide a complete two-layer closure of palatal defect resulting from a surgical complication of trans palatal resection of skull base chordoma. The nasal layer was reconstructed with triangular shape oral mucoperiosteal turn over hinge flap based on anterior margin of palatal defect and rectangular shaped lateral nasal mucosal hinge flaps. The oral layer was reconstructed with conventional pushback V-Y advancement 2-flaps palatoplasty. Each layer of the flaps were secured with two key mattress suture for flap coaptation. This technique has some advantages: simple, short operation time, one-stage procedure, no need of osteotomy. It can close small- to medium-sized palatal defect of palate or wide cleft palate and can prevent common complication of oronasal fistula, which could be caused by tension.

Geometric analysis of the V-Y advancement flap and its clinical applications.

PubMed

Andrades, Patricio R; Calderon, Wilfredo; Leniz, Patricio; Bartel, German; Danilla, Stefan; Benitez, Susana

2005-05-01

Geometry is fundamental in the comprehension of local flap design. The purpose of this study was to discuss the differences between the V-Y advancement flap and other local flaps, understand its geometry, and analyze its clinical applications. The analysis was based on qualitative measurements of an injury, taking into consideration the following dimensions: largest diameter, shortest diameter, and depth. Standardization of the flap design consisted of directing its advancement over the shortest diameter and making the V base match the size of the largest diameter. The flap was analyzed in two planes: the horizontal plane includes the V-Y design and the vertical plane includes the flap pedicle. The height of the flap can be obtained by simple trigonometry, taking into consideration the largest diameter and alpha angle in the horizontal plane. In the vertical plane, where the pedicle and pivot plane are positioned, for known shortest diameter and depth, the final depth of the pivot plane can be calculated using Pythagoras' principles. This analysis was applied to 25 patients with adequate skin coverage at follow-up. A correction factor was added to reduce the overdeepening of the vertical plane calculations. The final concepts for clinical application in the classic deep pedicle V-Y flap design are to calculate the length of the V by modifying the alpha angle and to move the pivot plane deeper to accomplish optimal flap movement. Using these principles, tension-free closure of the Y and appropriate advancement of the flap are obtained.

Full-scale wind tunnel-investigation of the Advanced Technology Light Twin-Engine airplane (ATLIT). [Langley full scale tunnel

NASA Technical Reports Server (NTRS)

Hassell, J. L., Jr.; Newsom, W. A., Jr.; Yip, L. P.

1980-01-01

An investigation was conducted to evaluate the aerodynamic performance, stability, and control characteristics of the Advanced Technology Light Twin Engine airplane (ATLIT). Data were measured over an angle of attack range from -4 deg to 20 deg for various angles of sideslip between -5 deg and 15 deg at Reynolds numbers of 0.0000023 and 0.0000035 for various settings of power and flap deflection. Measurements were also made by means of special thrust torque balances to determine the installed propeller characteristics. Part of the investigation was devoted to drag cleanup of the basic airplane and to the evaluation of the effect of winglets on drag and stability.

Probe Without Moving Parts Measures Flow Angle

NASA Technical Reports Server (NTRS)

Corda, Stephen; Vachon, M. Jake

2003-01-01

The measurement of local flow angle is critical in many fluid-dynamic applications, including the aerodynamic flight testing of new aircraft and flight systems. Flight researchers at NASA Dryden Flight Research Center have recently developed, flight-tested, and patented the force-based flow-angle probe (FLAP), a novel, force-based instrument for the measurement of local flow direction. Containing no moving parts, the FLAP may provide greater simplicity, improved accuracy, and increased measurement access, relative to conventional moving vane-type flow-angle probes. Forces in the FLAP can be measured by various techniques, including those that involve conventional strain gauges (based on electrical resistance) and those that involve more advanced strain gauges (based on optical fibers). A correlation is used to convert force-measurement data to the local flow angle. The use of fiber optics will enable the construction of a miniature FLAP, leading to the possibility of flow measurement in very small or confined regions. This may also enable the tufting of a surface with miniature FLAPs, capable of quantitative flow-angle measurements, similar to attaching yarn tufts for qualitative measurements. The prototype FLAP was a small, aerodynamically shaped, low-aspect-ratio fin about 2 in. (approximately equal to 5 cm) long, 1 in. (approximately equal to 2.5 cm) wide, and 0.125 in. (approximately equal to 0.3 cm) thick (see Figure 1). The prototype FLAP included simple electrical-resistance strain gauges for measuring forces. Four strain gauges were mounted on the FLAP; two on the upper surface and two on the lower surface. The gauges were connected to form a full Wheatstone bridge, configured as a bending bridge. In preparation for a flight test, the prototype FLAP was mounted on the airdata boom of a flight-test fixture (FTF) on the NASA Dryden F-15B flight research airplane.

Wind-tunnel free-flight investigation of a 0.15-scale model of the F-106B airplane with vortex flaps

NASA Technical Reports Server (NTRS)

Yip, Long P.

1987-01-01

An investigation to determine the effects of vortex flaps on the flight dynamic characteristics of the F-106B in the area of low-speed, high-angle-of-attack flight was undertaken on a 0.15-scale model of the airplane in the Langley 30- by 60-Foot Tunnel. Static force tests, dynamic forced-oscillation tests, as well as free-flight tests were conducted to obtain a data base on the flight characteristics of the F-106B airplane with vortex flaps. Vortex flap configurations tested included a full-span gothic flap, a full-span constant-chord flap, and a part-span gothic flap.

Normalized lift: an energy interpretation of the lift coefficient simplifies comparisons of the lifting ability of rotating and flapping surfaces.

PubMed

Burgers, Phillip; Alexander, David E

2012-01-01

For a century, researchers have used the standard lift coefficient C(L) to evaluate the lift, L, generated by fixed wings over an area S against dynamic pressure, ½ρv(2), where v is the effective velocity of the wing. Because the lift coefficient was developed initially for fixed wings in steady flow, its application to other lifting systems requires either simplifying assumptions or complex adjustments as is the case for flapping wings and rotating cylinders.This paper interprets the standard lift coefficient of a fixed wing slightly differently, as the work exerted by the wing on the surrounding flow field (L/ρ·S), compared against the total kinetic energy required for generating said lift, ½v(2). This reinterpreted coefficient, the normalized lift, is derived from the work-energy theorem and compares the lifting capabilities of dissimilar lift systems on a similar energy footing. The normalized lift is the same as the standard lift coefficient for fixed wings, but differs for wings with more complex motions; it also accounts for such complex motions explicitly and without complex modifications or adjustments. We compare the normalized lift with the previously-reported values of lift coefficient for a rotating cylinder in Magnus effect, a bat during hovering and forward flight, and a hovering dipteran.The maximum standard lift coefficient for a fixed wing without flaps in steady flow is around 1.5, yet for a rotating cylinder it may exceed 9.0, a value that implies that a rotating cylinder generates nearly 6 times the maximum lift of a wing. The maximum normalized lift for a rotating cylinder is 1.5. We suggest that the normalized lift can be used to evaluate propellers, rotors, flapping wings of animals and micro air vehicles, and underwater thrust-generating fins in the same way the lift coefficient is currently used to evaluate fixed wings.

Normalized Lift: An Energy Interpretation of the Lift Coefficient Simplifies Comparisons of the Lifting Ability of Rotating and Flapping Surfaces

PubMed Central

Burgers, Phillip; Alexander, David E.

2012-01-01

For a century, researchers have used the standard lift coefficient CL to evaluate the lift, L, generated by fixed wings over an area S against dynamic pressure, ½ρv 2, where v is the effective velocity of the wing. Because the lift coefficient was developed initially for fixed wings in steady flow, its application to other lifting systems requires either simplifying assumptions or complex adjustments as is the case for flapping wings and rotating cylinders. This paper interprets the standard lift coefficient of a fixed wing slightly differently, as the work exerted by the wing on the surrounding flow field (L/ρ·S), compared against the total kinetic energy required for generating said lift, ½v2. This reinterpreted coefficient, the normalized lift, is derived from the work-energy theorem and compares the lifting capabilities of dissimilar lift systems on a similar energy footing. The normalized lift is the same as the standard lift coefficient for fixed wings, but differs for wings with more complex motions; it also accounts for such complex motions explicitly and without complex modifications or adjustments. We compare the normalized lift with the previously-reported values of lift coefficient for a rotating cylinder in Magnus effect, a bat during hovering and forward flight, and a hovering dipteran. The maximum standard lift coefficient for a fixed wing without flaps in steady flow is around 1.5, yet for a rotating cylinder it may exceed 9.0, a value that implies that a rotating cylinder generates nearly 6 times the maximum lift of a wing. The maximum normalized lift for a rotating cylinder is 1.5. We suggest that the normalized lift can be used to evaluate propellers, rotors, flapping wings of animals and micro air vehicles, and underwater thrust-generating fins in the same way the lift coefficient is currently used to evaluate fixed wings. PMID:22629326

Fish biorobotics: kinematics and hydrodynamics of self-propulsion.

PubMed

Lauder, George V; Anderson, Erik J; Tangorra, James; Madden, Peter G A

2007-08-01

As a result of years of research on the comparative biomechanics and physiology of moving through water, biologists and engineers have made considerable progress in understanding how animals moving underwater use their muscles to power movement, in describing body and appendage motion during propulsion, and in conducting experimental and computational analyses of fluid movement and attendant forces. But it is clear that substantial future progress in understanding aquatic propulsion will require new lines of attack. Recent years have seen the advent of one such new avenue that promises to greatly broaden the scope of intellectual opportunity available to researchers: the use of biorobotic models. In this paper we discuss, using aquatic propulsion in fishes as our focal example, how using robotic models can lead to new insights in the study of aquatic propulsion. We use two examples: (1) pectoral fin function, and (2) hydrodynamic interactions between dorsal and caudal fins. Pectoral fin function is characterized by considerable deformation of individual fin rays, as well as spanwise (along the length) and chordwise (across the fin) deformation and area change. The pectoral fin can generate thrust on both the outstroke and instroke. A robotic model of the pectoral fin replicates this result, and demonstrates the effect of altering stroke kinematics on the pattern of force production. The soft dorsal fin of fishes sheds a distinct vortex wake that dramatically alters incoming flow to the tail: the dorsal fin and caudal fin act as dual flapping foils in series. This design can be replicated with a dual-foil flapping robotic device that demonstrates this phenomenon and allows examination of regions of the flapping performance space not available to fishes. We show how the robotic flapping foil device can also be used to better understand the significance of flexible propulsive surfaces for locomotor performance. Finally we emphasize the utility of self-propelled robotic devices as a means of understanding how locomotor forces are generated, and review different conceptual designs for robotic models of aquatic propulsion.

Pressure investigation of NASA leading edge vortex flaps on a 60 deg Delta wing

NASA Technical Reports Server (NTRS)

Marchman, J. F., III; Donatelli, D. A.; Terry, J. E.

1983-01-01

Pressure distributions on a 60 deg Delta Wing with NASA designed leading edge vortex flaps (LEVF) were found in order to provide more pressure data for LEVF and to help verify NASA computer codes used in designing these flaps. These flaps were intended to be optimized designs based on these computer codes. However, the pressure distributions show that the flaps wre not optimum for the size and deflection specified. A second drag-producing vortex forming over the wing indicated that the flap was too large for the specified deflection. Also, it became apparent that flap thickness has a possible effect on the reattachment location of the vortex. Research is continuing to determine proper flap size and deflection relationships that provide well-behaved flowfields and acceptable hinge-moment characteristics.

Abdominal- versus thigh-based reconstruction of perineal defects in patients with cancer.

PubMed

Pang, John; Broyles, Justin M; Berli, Jens; Buretta, Kate; Shridharani, Sachin M; Rochlin, Danielle H; Efron, Jonathan E; Sacks, Justin M

2014-06-01

An abdominoperineal resection is an invasive procedure that leaves the patient with vast pelvic dead space. Traditionally, the vertical rectus abdominus myocutaneous flap is used to reconstruct these defects. Oftentimes, this flap cannot be used because of multiple ostomy placements or previous abdominal surgery. The anterolateral thigh flap can be used; however, the efficacy of this flap has been questioned. We report a single surgeon's experience with perineal reconstruction in patients with cancer with the use of either the vertical rectus abdominus myocutaneous flap or the anterolateral thigh flap to demonstrate acceptable outcomes with either repair modality. From 2010 to 2012, 19 consecutive patients with perineal defects secondary to cancer underwent flap reconstruction. A retrospective chart review of prospectively entered data was conducted to determine the frequency of short-term and long-term complications. This study was conducted at an academic, tertiary-care cancer center. Patients in the study were patients with cancer who were receiving perineal reconstruction. Interventions were surgical and included either abdomen- or thigh-based reconstruction. The main outcome measures included infection, flap failure, length of stay, and time to radiotherapy. Of the 19 patients included in our study, 10 underwent anterolateral thigh flaps and 9 underwent vertical rectus abdominus myocutaneous flaps for reconstruction. There were no significant differences in demographics between groups (p > 0.05). Surgical outcomes and complications demonstrated no significant differences in the rate of infection, hematoma, bleeding, or necrosis. The mean length of stay after reconstruction was 9.7 ± 3.4 days (± SD) in the anterolateral thigh flap group and 13.4 ± 7.7 days in the vertical rectus abdominus myocutaneous flap group (p > 0.05). The limitations of this study include a relatively small sample size and retrospective evaluation. This study suggests that the anterolateral thigh flap is an acceptable alternative to the vertical rectus abdominus myocutaneous flap for perineal reconstruction (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A134).

Vascularized osseous flaps and assessing their bipartate perfusion pattern via intraoperative fluorescence angiography.

PubMed

Valerio, Ian; Green, J Marshall; Sacks, Justin M; Thomas, Shane; Sabino, Jennifer; Acarturk, T Oguz

2015-01-01

Large segmental bone and composite tissue defects often require vascularized osseous flaps for definitive reconstruction. However, failed osseous flaps due to inadequate perfusion can lead to significant morbidity. Utilization of indocyanine green (ICG) fluorescence angiography has been previously shown to reliably assess soft tissue perfusion. Our group will outline the application of this useful intraoperative tool in evaluating the perfusion of vascularized osseous flaps. A retrospective review was performed to identify those osseous and/or osteocutaneous bone flaps, where ICG angiography was employed. Data analyzed included flap types, success and failure rates, and perfusion-related complications. All osseous flaps were evaluated by ICG angiography to confirm periosteal and endosteal perfusion. Overall 16 osseous free flaps utilizing intraoperative ICG angiography to assess vascularized osseous constructs were performed over a 3-year period. The flaps consisted of the following: nine osteocutaneous fibulas, two osseous-only fibulas, two scapular/parascapular with scapula bone, two quadricep-based muscle flaps, containing a vascularized femoral bone component, and one osteocutaneous fibula revision. All flap reconstructions were successful with the only perfusion-related complication being a case of delayed partial skin flap loss. Intraoperative fluorescence angiography is a useful adjunctive tool that can aid in flap design through angiosome mapping and can also assess flap perfusion, vascular pedicle flow, tissue perfusion before flap harvest, and flap perfusion after flap inset. Our group has successfully extended the application of this intraoperative tool to assess vascularized osseous flaps in an effort to reduce adverse outcomes related to preventable perfusion-related complications. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

A novel composite adaptive flap controller design by a high-efficient modified differential evolution identification approach.

PubMed

Li, Nailu; Mu, Anle; Yang, Xiyun; Magar, Kaman T; Liu, Chao

2018-05-01

The optimal tuning of adaptive flap controller can improve adaptive flap control performance on uncertain operating environments, but the optimization process is usually time-consuming and it is difficult to design proper optimal tuning strategy for the flap control system (FCS). To solve this problem, a novel adaptive flap controller is designed based on a high-efficient differential evolution (DE) identification technique and composite adaptive internal model control (CAIMC) strategy. The optimal tuning can be easily obtained by DE identified inverse of the FCS via CAIMC structure. To achieve fast tuning, a high-efficient modified adaptive DE algorithm is proposed with new mutant operator and varying range adaptive mechanism for the FCS identification. A tradeoff between optimized adaptive flap control and low computation cost is successfully achieved by proposed controller. Simulation results show the robustness of proposed method and its superiority to conventional adaptive IMC (AIMC) flap controller and the CAIMC flap controllers using other DE algorithms on various uncertain operating conditions. The high computation efficiency of proposed controller is also verified based on the computation time on those operating cases. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

[Analysis of sequelae of the latissimus dorsi flap removal. Report of 44 cases reviewed and tested].

PubMed

Legré, R; Boghossian, V; Servant, J M; Magalon, G; Bureau, H

1990-01-01

Since Tanzini, the latissimus dorsi muscle flap has been widely used in plastic surgery. Based on the experience of two plastic surgery units, we decided to try to define the sequelae of this operation. In order to simplify our analysis we only considered free flaps. Out study is based on 42 patients (26 pure muscular flaps and 16 musculo-cutaneous flaps). The sequelae were analysed in terms of aesthetic and functional criteria. The aesthetic sequelae appeared to be minima in the case of pure muscular flaps, but more severe in the case of musculo-cutaneous flaps. Functional sequelae in the shoulder were observed on muscle testing in 30% of cases, although there were no repercussions on sport or work activities. Analysis of spinal posture demonstrated a modification in the frontal plane in 40% of cases although this could not be clearly attributed to the donor site. On the basis of this study, we can conclude that the latissimus dorsi flap retains an important place in the therapeutic arsenal of plastic surgery due to its reliability and its minor cicatricial and functional sequelae at the donor site.

One stage reconstruction of the floor of the mouth with a subcutaneous pedicled nasolabial flap.

PubMed

El-Marakby, Hamdy H; Fouad, Fouad A; Ali, Ahmed H

2012-06-01

Nasolabial flaps have been recognised as versatile flaps for a variety of defects in the face, nose, lip and the oral cavity. Random pattern inferiorly based nasolabial flaps (NLF) have been utilised for covering small defects on the anterior floor of the mouth, but usually require a second stage procedure to divide the flap base. A subcutaneous pedicled inferiorly based nasolabial flap can provide a one stage repair of moderate sized defects of the floor of the mouth after de epithelialisation of the base of the flap. To evaluate the feasibility of a single stage reconstruction of intermediate sized defects in the oral cavity with an inferiorly based pedicled NLF. The study includes the indications of use of the flap, flap design, technique, and the complications rate. The incidence of secondary procedures and the final functional and the aesthetic results will also be evaluated. A group of 20 patients presented with (T1-2) squamous cell carcinoma of the oral cavity have been treated at the Department of Surgery, National Cancer Institute, Cairo; in the period between January 2008 and September 2010. The pathology was confirmed with an incision biopsy and all metastatic work were carried out confirming that all patients were free from distant metastasis at presentation. Preoperative assessment also included assessment of the stage of the disease, the flap design and patient fitness for general anaesthesia. All patients underwent surgical excision combined with reconstruction of the defect with a subcutaneous inferiorly based pedicled NLF. The proximal part of the flap was routinely de epithelialised before it has been tunnelled through the cheek so a one stage procedure could only be required. The mean age of the patients was 62.3±6years, range (52-69years). All patients were diagnosed with squamous cell carcinoma. The anterior floor of the mouth constituted 40% of the defects, the lateral floor of the mouth 20% and the inner surface of the cheek 40%. There was no reported major complication; and only one patient suffered a reactionary haemorrhage that required re-exploration to secure the bleeder. A single procedure was adequate in most patients (80%), only 20% of patients required revision of the scar at the donor site or release of the tongue. The overall aesthetic results were either very satisfactory or satisfactory in the majority of patients (90%). Two patients were not satisfied with the final aesthetic results, one suffered from ectropion and the other had a donor site wound healing problem. The functional results (deglutition, speech) were satisfactory in most patients (70%), all were edentulous. An inferiorly based pedicled NLF is a reliable flap for the reconstruction of small and medium sized defects in the oral cavity. The flap can be best utilised for old edentulous and high risk patients where it can be used as a single stage procedure which is particularly useful in those types of patients. The flap can be safely combined with neck dissection even when the facial artery was ligated. Copyright © 2012 National Cancer Institute, Cairo University. Published by Elsevier B.V. All rights reserved.

The Economy in Autologous Tissue Transfer: Part 1. The Kiss Flap Technique.

PubMed

Zhang, Yi Xin; Hayakawa, Thomas J; Levin, L Scott; Hallock, Geoffrey G; Lazzeri, Davide

2016-03-01

All reconstructive microsurgeons realize the need to improve aesthetic and functional donor-site outcomes. A "kiss" flap design concept was developed to increase the surface area of skin flap coverage while minimizing donor-site morbidity. The main goal of the kiss flap technique is to harvest multiple skin paddles that are smaller than those raised with traditional techniques, to minimize donor-site morbidity. These smaller flap components are then sutured to each other, or said to kiss each other side-by-side, to create a large, wide flap. The skin paddles in the kiss technique can be linked to one another by a variety of native intrinsic vascular connections, by additional microanastomosis, or both. This technique can be widely applied to both free and pedicle flaps, and essentially allows for the reconstruction of a large defect while providing the easy primary closure of a smaller donor-site defect. According to their origin of blood supply, kiss flaps are classified into three styles and five types. All of the different types of kiss flaps are unique in both flap design and harvest technique. Most kiss flaps are based on common flaps already familiar to the reconstructive surgeon. The basis of the kiss flap design concept is to convert multiple narrow flaps into a single unified flap of the desired greater width. This maximizes the size of the resulting flap and minimizes donor-site morbidity, as a direct linear closure is usually possible. Therapeutic, V.

Improved wound healing of postischemic cutaneous flaps with the use of bone marrow-derived stem cells.

PubMed

Hu, Melissa; Ludlow, David; Alexander, J Steven; McLarty, Jerry; Lian, Timothy

2014-03-01

To determine if the intravascular delivery of mesenchymal stem cells improves wound healing and blood perfusion to postischemic cutaneous flap tissues. Randomized controlled study. A murine model of a cutaneous flap was created based on the inferior epigastric vessels. Mice (n = 14) underwent 3.5 hours of ischemia followed by reperfusion. Bone marrow stromal cells (BMSCs) 1 × 10(6) were injected intravenously. Wound healing was then assessed measuring percent flap necrosis, flap perfusion, and tensile strength of the flap after a period of 14 days. Localization of BMSCs was determined with radiolabeled and fluorescent labeled BMSCs. Postischemic cutaneous flap tissues treated with BMSCs demonstrated significantly less necrosis than control flaps (P <0.01). Beginning on postoperative day 5, BMSC-treated flaps demonstrated greater blood perfusion than untreated flaps (P <0.01). Tensile strength of BMSC-treated cutaneous flaps was significantly higher (P <0.01), with a mean strength of 283.4 ± 28.4 N/m than control flaps with a mean of 122.4 ± 23.5 N/m. Radiolabeled BMSCs localized to postischemic flaps compared to untreated tissues (P = 0.001). Fluorescent microscopy revealed incorporation of BMSCs into endothelial and epithelial tissues of postischemic flaps. This study demonstrates that the intravascular delivery of BMSCs increases wound healing and promotes flap survival following ischemia-reperfusion injury of cutaneous tissue flaps. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Experience with peroneus brevis muscle flaps for reconstruction of distal leg and ankle defects

PubMed Central

Bajantri, Babu; Bharathi, Ravindra; Ramkumar, Sanjai; Latheef, Latheesh; Dhane, Smitha; Sabapathy, S. Raja

2013-01-01

Objective: Peroneus brevis is a muscle in the leg which is expendable without much functional deficit. The objective of this study was to find out its usefulness in coverage of the defects of the lower leg and ankle. Patients and Methods: A retrospective analysis of the use of 39 pedicled peroneus brevis muscle flaps used for coverage of defects of the lower leg and ankle between November 2010 and December 2012 was carried out. The flaps were proximally based for defects of the lower third of the leg in 12 patients and distally based for reconstruction of defects of the ankle in 26 patients, with one patient having flaps on both ankles. Results: Partial flap loss in critical areas was found in four patients requiring further flap cover and in non-critical areas in two patients, which were managed with a skin graft. Three of the four critical losses occurred when we used it for covering defects over the medial malleolus. There was no complete flap loss in any of the patients. Conclusion: This flap has a unique vascular pattern and fails to fit into the classification of the vasculature of muscles by Mathes and Nahai. The unusual feature is an axial vessel system running down the deep aspect of the muscle and linking the perforators from the peroneal artery and anterior tibial artery, which allows it to be raised proximally or distally on a single perforator. The flap is simple to raise and safe for the reconstruction of small-to moderate-sized skin defects of the distal third of the tibia and all parts of the ankle except the medial malleolus, which is too far from the pedicle of the distally based flap. The donor site can be closed primarily to provide a linear scar. The muscle flap thins with time to provide a good result aesthetically at the primary defect. PMID:23960305

Retention of a reconstructed nipple using a C-V flap with different layer thicknesses in the C-flap.

PubMed

Sowa, Yoshihiro; Itsukage, Sizu; Sakaguchi, Kouichi; Taguchi, Tetsuya; Numajiri, Toshiaki

2018-04-01

The C-V flap for nipple reconstruction is now one of standard surgical techniques. But decreased projection is still a problem. In recent years, it has been suggested that projection can be more easily maintained when raising of the C-flap is performed with a split thickness dermis. In this study, we examined whether decrease of projection can be prevented by raising of a C-flap with a split dermis rather than with full dermis. A total of 49 consecutive patients who underwent reconstruction of a nipple using the C-V flap technique were enrolled. The patients included 22 who underwent surgery using a C-flap with a full thickness dermis (Group F), and 27 who underwent surgery with raising of a flap with a split thickness dermis (Group S). The size of the reconstructed nipple was measured at 2 weeks, 6 months and 1 year postoperatively for comparison between Groups F and S. Partial necrosis of the C-flap end occurred in 4 subjects in only Group S. The decrease in projection after 1 year postoperatively in Group S was significantly lower than that in Group F. In contrast, the teat base size in Group F tended to be greater than that in Group S, suggesting a tendency for an expanded base using a flap with a full dermis. Our results indicated that it is recommended to use a C-flap with a split dermis for cases with high projection of the nipple on the contralateral side.

The use of computed tomography for the estimation of DIEP flap weights in breast reconstruction: a simple mathematical formula.

PubMed

Nanidis, Theodore G; Ridha, Hyder; Jallali, Navid

2014-10-01

Estimation of the volume of abdominal tissue is desirable when planning autologous abdominal based breast reconstruction. However, this can be difficult clinically. The aim of this study was to develop a simple, yet reliable method of calculating the deep inferior epigastric artery perforator flap weight using the routine preoperative computed tomography angiogram (CTA) scan. Our mathematical formula is based on the shape of a DIEP flap resembling that of an isosceles triangular prism. Thus its volume can be calculated with a standard mathematical formula. Using bony landmarks three measurements were acquired from the CTA scan to calculate the flap weight. This was then compared to the actual flap weight harvested in both a retrospective feasibility and prospective study. In the retrospective group 17 DIEP flaps in 17 patients were analyzed. Average predicted flap weight was 667 g (range 293-1254). The average actual flap weight was 657 g (range 300-1290) giving an average percentage error of 6.8% (p-value for weight difference 0.53). In the prospective group 15 DIEP flaps in 15 patients were analyzed. Average predicted flap weight was 618 g (range 320-925). The average actual flap weight was 624 g (range 356-970) giving an average percentage error of 6.38% (p-value for weight difference 0.57). This formula is a quick, reliable and accurate way of estimating the volume of abdominal tissue using the preoperative CTA scan. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

[Clinical experience with the supraclavicular flap to reconstruct head and neck defects].

PubMed

Zhang, Bin; Yan, Dangui; Zhang, Yabing; Zhang, Xiwei; Wan, Hanfeng

2015-06-01

To evaluate the efficacy of pedicled supraclavicular artery island flaps for head and neck reconstruction. Reconstructive surgeries for head and neck oncologic defects were performed with the pedicled supraclavicular artery island flaps in 10 patients from May 2013 to December 2014 and the cases were review. Among them, 6 were performed for hypopharyngeal cancer, 2 for oral tongue cancer, 1 for oral base cancer and 1 for cervical esophageal cancer. The size of the flaps was measured in (5-8) cm × (6-12) cm. Seven flaps survived, one flap failured and two flaps had partial necrosis. Donor sites were closed primarily without morbidity. The pedicled supraclavicular artery island flap is an easy harvesting and reliable for head and neck reconstruction, especially suitable for otolaryngo-head and neck surgeon and maxillofacial surgeon in the local hospital.

Hypersonic and transonic buzz measurements on the lower pitch flap of the M2-F2 lifting entry configuration

NASA Technical Reports Server (NTRS)

Warner, R. W.; Wilcox, P. R.

1972-01-01

Free-oscillation damping measurements at hypersonic and transonic Mach numbers are presented for the lower pitch flap of the M2-F2 reentry vehicle. For the flow and model conditions tested, the damping measurements indicate the absence of hypersonic buzz instability for flap rotation frequencies of 47.3 Hz, 153 Hz, and 360 Hz, the presence of transonic buzz for 47.3 Hz flap, and the absence of transonic buzz for a 115 Hz flap. There are not enough flap damping data for an error estimate based on repeatability, but a partial damping calibration is presented in which an analog computer simulation of random flap response for a known flap damping is fed into the autocorrelation computer and filter combination used for most of the damping measurements.

Dynamic perfusion assessment during perforator flap surgery: an up-to-date

PubMed Central

MUNTEAN, MAXIMILIAN VLAD; MUNTEAN, VALENTIN; ARDELEAN, FILIP; GEORGESCU, ALEXANDRU

2015-01-01

Flap monitoring technology has progressed alongside flap design. The highly variable vascular anatomy and the complexity associated with modern perforator flaps demands dynamic, real-time, intraoperative information about the vessel location, perfusion patterns and flap physiology. Although most surgeons still assess flap perfusion and viability based solely on clinical experience, studies have shown that results may be highly variable and often misleading. Poor judgment of intraoperative perfusion leads to major complications. Employing dynamic perfusion imaging during flap reconstruction has led to a reduced complication rate, lower morbidity, shorter hospital stay, and an overall better result. With the emergence of multiple systems capable of intraoperative flap evaluation, the purpose of this article is to review the two systems that have been widely accepted and are currently used by plastic surgeons: Indocyanine green angiography (ICGA) and dynamic infrared thermography (DIRT). PMID:26609259

Temporalis myofascial flap for primary cranial base reconstruction after tumor resection.

PubMed

Eldaly, Ahmed; Magdy, Emad A; Nour, Yasser A; Gaafar, Alaa H

2008-07-01

To evaluate the use of the temporalis myofascial flap in primary cranial base reconstruction following surgical tumor ablation and to explain technical issues, potential complications, and donor site consequences along with their management. Retrospective case series. Tertiary referral center. Forty-one consecutive patients receiving primary temporalis myofascial flap reconstructions following cranial base tumor resections in a 4-year period. Flap survival, postoperative complications, and donor site morbidity. Patients included 37 males and 4 females ranging in age from 10 to 65 years. Two patients received preoperative and 18 postoperative radiation therapy. Patient follow-up ranged from 4 to 39 months. The whole temporalis muscle was used in 26 patients (63.4%) and only part of a coronally split muscle was used in 15 patients (36.6%). Nine patients had primary donor site reconstruction using a Medpor((R)) (Porex Surgical, Inc., Newnan, GA) temporal fossa implant; these had excellent aesthetic results. There were no cases of complete flap loss. Partial flap dehiscence was seen in six patients (14.6%); only two required surgical débridement. None of the patients developed cerebrospinal leaks or meningitis. One patient was left with complete paralysis of the temporal branch of the facial nerve. Three patients (all had received postoperative irradiation) developed permanent trismus. The temporalis myofascial flap was found to be an excellent reconstructive alternative for a wide variety of skull base defects following tumor ablation. It is a very reliable, versatile flap that is usually available in the operative field with relatively low donor site aesthetic and functional morbidity.

Lower extremity soft tissue reconstruction with free flap based on subscapular artery.

PubMed

Karşıdağ, Semra; Akçal, Arzu; Turgut, Gürsel; Uğurlu, Kemal; Baş, Lütfü

2011-01-01

The purpose of our study was to evaluate the results of the reconstruction of the lower extremity defects with free flaps based on the subscapular artery. Between January, 1998 and December, 2008, 51 patients (mean age 26 years; 16 female and 35 male) presenting with a lower extremity defect underwent a reconstructive surgery with flaps based on the subscapular vascular system. Thirty-seven percent of the defects were located in the crus, 19% in the sole, 16% in the heel, and 14% in the dorsum of the foot. Eighty and a half percent of the patients had traffic-accident-related and 13.5% had burn-related tissue defects. Fifty-three percent of the patients presenting with lower extremity defects underwent reconstruction with latissimus dorsi muscle flaps, 21% with free serratus muscle and/or fascia flaps, 14% with free parascapular fasciocutaneous flaps, and 12% with free combined latissimus muscle and serratus muscle and/or fascia flaps. Anastomoses of 80% of the patients were performed on their posterior tibial artery and accompanying veins and/or foot dorsal veins. End-to-end anastomosis was performed on 14 patients, while 35 patients received end-to-side anastomosis. Six patients were treated with cross free flaps, of which 4 received cross latissimus, 1 cross serratus, and 1 cross combined serratus and latissimus flaps. End-to-side anastomoses were performed on these patients on the cross-leg tibialis posterior artery. The cross-leg anastomosis was freed 4 weeks later. In the early period, venous occlusion was observed in 4 patients and arterial and venous occlusion was present in 1 patient. New anastomoses were performed in these patients. Partial necrosis was observed in 2 patients. The average follow-up period was 61 months. Pressure-related late ulcerative lesions developed in 4 patients. The lesions of these patients were repaired by debridement and primary suturing or partial thickness skin grafts. The subscapular vascular system based flaps have an optimal vascularity once they are prepared with adequate pedicles, causing minimal donor site morbidity. These flaps are a safe and effective alternative in lower extremity reconstruction. On the other hand, in the absence of appropriate recipient vessels, single or combined cross-leg free flaps may provide successful repair.

A Novel Perforator Flap Training Model Using a Chicken Leg.

PubMed

Cifuentes, Ignacio J; Yañez, Ricardo A; Salisbury, Maria C; Rodriguez, José R; Varas, Julian E; Dagnino, Bruno L

2016-04-01

Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training.

Reverse pedicle-based greater saphenous neuro-veno-fasciocutaneous flap for reconstruction of lower leg and foot.

PubMed

Kansal, Sandeep; Goil, Pradeep; Agarwal, Vijay; Agarwal, Swarnima; Mishra, Shashank; Agarwal, Deepak; Singh, Pranay

2014-01-01

Paucity of soft tissue available locally for reconstruction of defects in leg and foot presents a challenge for reconstructive surgeon. The use of reverse pedicle-based greater saphenous neuro-veno-fasciocutaneous flap in reconstruction of lower leg and foot presents a viable alternative to free flap and cross-leg flap reconstruction. The vascular axis of the flap is formed by the vessels accompanying the saphenous nerve and the greater saphenous vein. We present here our experience with reverse saphenous neurocutaneous flap which provides a stable cover without the need to sacrifice any important vessel of leg. The study is conducted from March 2003 through Dec 2009 and included a total of 96 patients with defects in lower two-thirds of leg and foot. There are 74 males and 22 females. Distal pivot point was kept approximately 5-6 cm from tip of medial malleolus, thus preserving the distal most perforator, and the flap is turned and inserted into the defect. Donor site is covered with a split thickness skin graft. Postoperative follow-up period was 6 weeks to 6 months. The procedure is uneventful in 77 cases. Infection is observed in 14 cases. Partial flap necrosis occurs in 2 cases. Total flap necrosis is noted in 3 cases. Reverse pedicle saphenous flap can be used to reconstruct defects of lower one-third leg and foot with a reliable blood supply with a large arc of rotation while having minimal donor site morbidity.

"Palmar pivot flap" for resurfacing palmar lateral defects of the fingers.

PubMed

Yam, Andrew; Peng, Yeong-Pin; Pho, Robert Wan-Heng

2008-12-01

Soft tissue defects on the lateral borders of the digits are difficult to reconstruct using local or local-regional flaps. We describe a "palmar pivot flap" to resurface an adjacent defect on the palmar-lateral aspect of the digit. The surgical technique is described. This flap is an axial pattern flap based on the subcutaneous transverse branches of the digital artery. The flap is pivoted up to 90 degrees on the neurovascular bundle in its base, into an adjacent defect. The flap can be raised from either the proximal or the middle phalangeal segments. It can cover defects sited from the level of the proximal interphalangeal joint up to the fingertip. The donor defect is limited to the same digit and is covered with a full-thickness skin graft. We have used this flap on 3 patients with defects at the middle phalangeal segment, the distal interphalangeal joint, and the fingertip. All healed primarily. One patient had a mild flexion contracture of the proximal interphalangeal joint, whereas the other 2 had no complications. The patients with distal interphalangeal joint and fingertip defects had excellent sensation in the flap (2-point discrimination of 5-6 mm). The palmar pivot flap is useful for resurfacing otherwise difficult defects on the lateral borders of the digits around and distal to the proximal interphalangeal joint, including those at the fingertip. It provides sensate, glabrous skin. The donor defect is on the same digit and is well hidden, producing an aesthetic and functional reconstruction.

Cost analysis of postmastectomy reconstruction: A comparison of two staged implant reconstruction using tissue expander and acellular dermal matrix with abdominal-based perforator free flaps.

PubMed

Tran, Bao Ngoc N; Fadayomi, Ayotunde; Lin, Samuel J; Singhal, Dhruv; Lee, Bernard T

2017-09-01

Two staged tissue expander-implant with acellular dermal matrix (TE/I + ADM) and deep inferior epigastric perforator (DIEP) flap are the most common implant and autologous methods of reconstruction in the U.S. Implant-based techniques are disproportionally more popular, partially due to its presumed cost effectiveness. We performed a comprehensive cost analysis to compare TE/I + ADM and DIEP flap. A comparative cost analysis of TE/I + ADM and DIEP flap was performed. Medicare reimbursement costs for each procedure and their associated complications were calculated. Pooled probabilities of complications including cellulitis, seroma, skin necrosis, implant removal, flap loss, partial flap loss, and fat necrosis, were calculated using published studies from 2010 to 2016. Average actual cost for successful TE/I + ADM and DIEP flap were $13 304.55 and $10 237.13, respectively. Incorporating pooled complication data from published literature resulted in an increase in cost to $13 963.46 for TE/I + ADM and $12 624.29 for DIEP flap. The expected costs for successful TE/I + ADM and DIEP flap were $9700.35 and $8644.23, which are lower than the actual costs. DIEP flap breast reconstruction incurs lower costs compared to TE/I + ADM. These costs are lower at baseline and when additional costs from pooled complications are incorporated. © 2017 Wiley Periodicals, Inc.

"Internet of Things" Real-Time Free Flap Monitoring.

PubMed

Kim, Sang Hun; Shin, Ho Seong; Lee, Sang Hwan

2018-01-01

Free flaps are a common treatment option for head and neck reconstruction in plastic reconstructive surgery, and monitoring of the free flap is the most important factor for flap survival. In this study, the authors performed real-time free flap monitoring based on an implanted Doppler system and "internet of things" (IoT)/wireless Wi-Fi, which is a convenient, accurate, and efficient approach for surgeons to monitor a free flap. Implanted Doppler signals were checked continuously until the patient was discharged by the surgeon and residents using their own cellular phone or personal computer. If the surgeon decided that a revision procedure or exploration was required, the authors checked the consumed time (positive signal-to-operating room time) from the first notification when the flap's status was questioned to the determination for revision surgery according to a chart review. To compare the efficacy of real-time monitoring, the authors paired the same number of free flaps performed by the same surgeon and monitored the flaps using conventional methods such as a physical examination. The total survival rate was greater in the real-time monitoring group (94.7% versus 89.5%). The average time for the real-time monitoring group was shorter than that for the conventional group (65 minutes versus 86 minutes). Based on this study, real-time free flap monitoring using IoT technology is a method that surgeon and reconstruction team can monitor simultaneously at any time in any situation.

Reconstruction of midfoot bone and soft tissue loss with chimeric partial scapula and latissimus dorsi muscle flap and short perforator-based skin flap following gunshot injuries: Report of two cases.

PubMed

Ozcan Akcal, Arzu; Ünal, Kerim; Gorgulu, Tahsin; Akif Akcal, Mehmet; Bigat, Zekiye

2016-10-01

In this report we present two cases of gunshot injury related midfoot defects, reconstructed with a chimeric partial scapula and latissimus dorsi muscle flap and short perforator-based skin flap. The first case, a 14 years old male, had 10 × 8 cm medial plantar and 6 × 4 cm dorsal foot defects and the second case, a 55 years old female, had only 8 × 6 cm dorsal foot defect. In both cases the defects were associated with fractures, one with lateral cuneiform and cuboid with 90% bone loss and the other with navicular bone, respectively. After 6 months, the patients could walk well without support, and radiographs confirmed bony union. A chimeric partial scapula and latissimus dorsi muscle flap and short perforator-based skin flap may be used for the reconstruction of combined bony and soft tissue defects of the midfoot and to promote bone healing. © 2016 Wiley Periodicals, Inc. Microsurgery 36:598-603, 2016. © 2016 Wiley Periodicals, Inc.

Superfast 3D shape measurement of a flapping flight process with motion based segmentation

NASA Astrophysics Data System (ADS)

Li, Beiwen

2018-02-01

Flapping flight has drawn interests from different fields including biology, aerodynamics and robotics. For such research, the digital fringe projection technology using defocused binary image projection has superfast (e.g. several kHz) measurement capabilities with digital-micromirror-device, yet its measurement quality is still subject to the motion of flapping flight. This research proposes a novel computational framework for dynamic 3D shape measurement of a flapping flight process. The fast and slow motion parts are separately reconstructed with Fourier transform and phase shifting. Experiments demonstrate its success by measuring a flapping wing robot (image acquisition rate: 5000 Hz; flapping speed: 25 cycles/second).

Free flap reconstruction for diabetic foot limb salvage.

PubMed

Sato, Tomoya; Yana, Yuichiro; Ichioka, Shigeru

2017-12-01

Although free flap is gaining popularity for the reconstruction of diabetic foot ulcers, it is unclear whether free flap reconstruction increases the chances of postoperative independent ambulation. The aim of this study is to evaluate the relationship between free flap success and postoperative ambulation. This study reviewed 23 cases of free flap reconstruction for diabetic foot ulcers between January 2007 and March 2014. Free rectus abdominis, latissimus dorsi, and anterolateral thigh flaps were used in ten, eight, and five patients, respectively. A comparison was made between free flap success and postoperative independent ambulation using Fisher's exact test. Two patients developed congestive heart failure with fatal consequences within 14 days postoperatively, resulting in an in-hospital mortality rate of 8.7%. Five patients lost their flaps (21.7%). Of the 16 patients who had flap success, 12 achieved independent ambulation. Five patients with flap loss did not achieve independent ambulation, except one patient who underwent secondary flap reconstruction using a distally based sural flap. Fisher's exact test revealed that independent ambulation was associated with free flap success (p = 0.047). The present study indicates that free flap reconstruction may increase the possibility of independent ambulation for patients with extensive tissue defects due to diabetic ulcers. Intermediate limb salvage rates and independent ambulation rates were favourable in patients with successful reconstruction. The use of foot orthoses and a team approach with pedorthists were effective to prevent recurrence.

Free-style free flaps.

PubMed

Wei, Fu-Chan; Mardini, Samir

2004-09-15

Free-tissue transfer has become the accepted standard for reconstruction of complex defects. With the growth of this field, anatomic studies and clinical work have added many flaps to the armamentarium of the microvascular surgeon. Further advancements and experience with techniques of perforator flap surgery have allowed for the harvest of flaps in a free-style manner, where a flap is harvested based only on the preoperative knowledge of Doppler signals present in a specific region. Between June of 2002 and September of 2003, 13 free-style free flaps were harvested from the region of the thigh. All patients presented with an oral or pharyngeal cancer and underwent resection and immediate reconstruction of these flaps. All flaps were cutaneous and were harvested in a suprafascial plane. The average size of the flaps was 108 cm2 (range, 36 to 187 cm2), and the average length of the vascular pedicle was 10 cm (range, 9 to 12 cm). All flaps were successful in achieving wound coverage and functional outcomes without any vascular compromise necessitating re-exploration. Free-style free flaps have become a clinical reality. The concepts and techniques used to harvest a free-style free flap will aid in dealing with anatomic variations that are encountered during conventional flap harvest. Future trends in flap selection will focus mainly on choosing tissue with appropriate texture, thickness, and pliability to match requirements at the recipient site while minimizing donor-site morbidity.

The posterior thigh flap for defect coverage of ischial pressure sores - a critical single-centre analysis.

PubMed

Djedovic, Gabriel; Morandi, Evi M; Metzler, Julia; Wirthmann, Anna; Matiasek, Johannes; Bauer, Thomas; Rieger, Ulrich M

2017-12-01

The development of pressure sores is still not only an enormous economical but also a medical burden. Especially in the ischial region, the local defect coverage remains demanding as it is the main weight-bearing area in wheelchair-mobilised patients and is prone to high mobility. The purpose of our study was to report our long-time experience with the reconstruction of ischial pressure ulcers with the medially based posterior thigh flap. A retrospective analysis of all primary pressure sores grade III-IV in the ischial area, which were covered with a medially based posterior thigh flap between January 2008 and December 2014, at our department was conducted. A total of 28 patients underwent defect coverage of an ischial pressure sore with the aforementioned flap. The subgroup with complications showed a statistically significant longer hospital stay. A statistically significant correlation between age and the coincidence of comorbidities could be seen. Older patients showed significantly higher grades of pressure sores. The medially based posterior thigh flap is a safe and reliable flap design. Complication rates are comparable to other flaps. Nevertheless, in case of complications, a significantly longer duration of hospitalisation has to be taken into account. © 2017 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Indocyanine green laser angiography improves deep inferior epigastric perforator flap outcomes following abdominal suction lipectomy.

PubMed

Casey, William J; Connolly, Katharine A; Nanda, Alisha; Rebecca, Alanna M; Perdikis, Galen; Smith, Anthony A

2015-03-01

The reliability of deep inferior epigastric artery perforator (DIEP) flap reconstruction following abdominal liposuction is controversial. The authors' early cases were technically successful; however, they experienced high partial flap loss and fat necrosis rates. The authors sought to compare DIEP flap outcomes in the setting of prior liposuction after the use of intraoperative indocyanine green angiography compared to when flaps were assessed on clinical grounds alone. A retrospective review of a consecutive series of DIEP flaps following liposuction at a single institution was performed, comparing those evaluated on clinical grounds alone and those in which indocyanine green angiography was used intraoperatively. Outcomes measured included anastomotic complications, total flap loss, partial flap loss, fat necrosis, and postoperative abdominal wounds. Thirteen DIEP flaps following prior liposuction were performed on 11 patients from July of 2003 through January of 2014. All patients had preoperative imaging with duplex ultrasound or computed tomographic angiography to analyze perforator suitability before surgical exploration. Seven flaps were evaluated intraoperatively on clinical grounds alone. Six flaps were assessed and modified based on indocyanine green angiography. All flaps were successful; however, partial flap loss and fat necrosis rates dropped from 71.4 percent to 0 percent when indocyanine green angiography was used intraoperatively (p = 0.02). Indocyanine green angiography is an excellent vascular imaging modality for intraoperative use to assess flap perfusion, and improves outcomes in DIEP flaps when harvested after prior abdominal suction lipectomy.

Bilateral superiorly based full-thickness nasolabial island flaps for closure of residual anterior palatal fistulas in an unoperated elderly patient.

PubMed

Erçöçen, A R; Yilmaz, S; Saydam, M

2003-01-01

Unoperated bilateral complete cleft lip and palate in an adult or elderly patient is seen rarely, and the existence of unoperated clefts is a result of unfavorable economic and social circumstances. We report an unoperated 65-year-old patient with bilateral complete cleft lip and palate and present our preference for the surgical management. Repair of the bilateral complete cleft lip and palate was successfully carried out using straight-line closure for the bilateral cleft lip and two-flap pushback palatoplasty with superiorly based lateral port control pharyngeal flap for the wide cleft palate at the first stage, and large residual anterior palatal fistulas were closed using bilateral superiorly based (retrograde flow) full-thickness nasolabial island flaps at the second stage. To our knowledge based on a review of the literature, this is the first report of an elderly patient with bilateral complete cleft lip and palate and the first application of bilateral superiorly based (retrograde flow) full-thickness nasolabial island flaps for closure of large residual anterior palatal fistulas or alveolar clefts. The bilateral superiorly based (retrograde flow) full-thickness nasolabial island flap may be a good solution in large anterior palatal defects using unilaterally or bilaterally in a single stage with minimal donor site morbidity, in which there is not enough tissue for local repair or if previous attempts are unsuccessful.

Reconstruction of Facial Defect Using Deltopectoral Flap.

PubMed

Aldelaimi, Tahrir N; Khalil, Afrah A

2015-11-01

Reconstruction of the head and neck is a challenge for otolarygology surgeons, maxillofacial surgeons as well as plastic surgeons. Defects caused by the resection and/or trauma should be closed with flaps which match in color, texture and hair bearing characteristics with the face. Deltopectoral flap is a one such flap from chest and neck skin mainly used to cover the facial defects. This study report a patient presenting with tragic Road Traffic Accident (RTA) admitted to maxillofacial surgery department at Ramadi Teaching Hospital, Anbar province, Iraq. An incision, medially based, was done and deltopectoral fascio-cutaneous flap was used for surgical exposure and closure of defects after RTA. There was no major complication. Good aesthetic and functional results were achieved. Deltopectoral flap is an excellent alternative for the reconstruction of head and neck. Harvesting and application of the flap is rapid and safe. Only a single incision is sufficient for dissection and flap elevation.

Biochemical analyses indicate that binding and cleavage specificities define the ordered processing of human Okazaki fragments by Dna2 and FEN1.

PubMed

Gloor, Jason W; Balakrishnan, Lata; Campbell, Judith L; Bambara, Robert A

2012-08-01

In eukaryotic Okazaki fragment processing, the RNA primer is displaced into a single-stranded flap prior to removal. Evidence suggests that some flaps become long before they are cleaved, and that this cleavage involves the sequential action of two nucleases. Strand displacement characteristics of the polymerase show that a short gap precedes the flap during synthesis. Using biochemical techniques, binding and cleavage assays presented here indicate that when the flap is ∼ 30 nt long the nuclease Dna2 can bind with high affinity to the flap and downstream double strand and begin cleavage. When the polymerase idles or dissociates the Dna2 can reorient for additional contacts with the upstream primer region, allowing the nuclease to remain stably bound as the flap is further shortened. The DNA can then equilibrate to a double flap that can bind Dna2 and flap endonuclease (FEN1) simultaneously. When Dna2 shortens the flap even more, FEN1 can displace the Dna2 and cleave at the flap base to make a nick for ligation.

[A reverse vascular autograft finger island flap. A review of 15 cases and of the literature].

PubMed

Adani, R; Marcuzzi, A; Busa, R; Pancaldi, G; Bathia, A; Caroli, A

1995-01-01

The authors discuss the indications for homodigital island flap with a reverse vascular pedicle. This flap is based on the anastomoses between the radial and ulnar digital arteries. These anastomotic branches lie between the posterior wall of the tendon sheath and the periosteum to form an arch and are named the "digitopalmar arches". The vascularization of the reverse homodigital island flap is derived by using the middle transverse palmar arch. This flap was performed successfully in 14 patients involving 15 fingers to resurface amputation of the distal phalanx. In 6 cases the flap was used as an "artery" flap, and in 9 cases as a "sensitive" homodigital island flap. The pedicle in these cases was neurovascular also containing the digital nerve. The sensitivity of the flap was obtained by neurorraphy between the transposed digital nerve of the flap and the receiving digital nerve of the recipient finger. This technique achieves cover of the tactile pad in one operative stage and provides well vascularized skin allowing early mobilization. Sensation of the flap can be restored rapidly when neurorraphy of the transposed digital nerve is performed.

Effect of Krueger nose flaps on the experimental force and moment characteristics of an oblique wing

NASA Technical Reports Server (NTRS)

Hopkins, E. J.; Lovette, G. H.

1976-01-01

Experimental force and moment data are presented for an oblique wing mounted on a body of revolution and equipped with Krueger type nose flaps. The effectiveness of these flaps in making the moment curves more linear by controlling the flow separation on the downstream wing panel at high lift coefficients was determined. The investigation of the effects of the Krueger flaps covered two cases: (1) use of the flaps on the downstream wing panel only and (2) use of the flaps on both wing panels. For part of the tests, the Krueger flaps were mounted on nose flaps that were drooped either 5 deg or 10 deg. The wing was elliptical in planform, had an aspect ratio of 6.0 (based on the unswept span) and was tested at sweep angles of 0, 45 deg, and 50 deg. The Mach-number range covered was from 0.25 to 0.95. It was found that the most effective arrangement of the Krueger flaps for making the pitching-, rolling-, and yawing-moment curves more linear at high lift coefficients was having the Krueger flaps mounted on the nose flaps drooped 5 deg and only on the downstream wing panel.

Development of HAN-based Liquid Propellant Thruster

NASA Astrophysics Data System (ADS)

Hisatsune, K.; Izumi, J.; Tsutaya, H.; Furukawa, K.

2004-10-01

Many of propellants that are applied to the conventional spacecraft propulsion system are toxic propellants. Because of its toxicity, considering the environmental pollution or safety on handling, it will be necessary to apply the "green" propellant to the spacecraft propulsion system. The purpose of this study is to apply HAN based liquid propellant (LP1846) to mono propellant thruster. Compared to the hydrazine that is used in conventional mono propellant thruster, HAN based propellant is not only lower toxic but also can obtain higher specific impulse. Moreover, HAN based propellant can be decomposed by the catalyst. It means there are the possibility of applying to the mono propellant thruster that can leads to the high reliability of the propulsion system.[1],[2] However, there are two technical subjects, to apply HAN based propellant to the mono propellant thruster. One is the high combustion temperature. The catalyst will be damaged under high temperature condition. The other is the low catalytic activity. It is the serious problem on application of HAN based propellant to the mono propellant thruster that is used for attitude control of spacecraft. To improve the catalytic activity of HAN based propellant, it is necessary to screen the best catalyst for HAN based propellant. The adsorption analysis is conducted by Monte Carlo Simulation to screen the catalyst metal for HAN and TEAN. The result of analysis shows the Iridium is the best catalyst metal for HAN and TEAN. Iridium is the catalyst metal that is used at conventional mono propellant thruster catalyst Shell405. Then, to confirm the result of analysis, the reaction test about catalyst is conducted. The result of this test is the same as the result of adsorption analysis. That means the adsorption analysis is effective in screening the catalyst metal. At the evaluating test, the various types of carrier of catalyst are also compared to Shell 405 to improve catalytic activity. The test result shows the inorganic porous media is superior to Shell405 in catalytic activity. Next, the catalyst life with HAN based propellant (LP1846) is evaluated. The Shell405 and inorganic porous media catalyst are compared at the life test. The test result shows the inorganic porous media catalyst is superior to Shell405 in catalyst life. In this paper, the detail of the result of adsorption analysis and evaluating test are reported.

[Surgical issues and outcomes in ischial pressure sores treatment].

PubMed

Voulliaume, D; Grecea, M; Viard, R; Brun, A; Comparin, J-P; Foyatier, J-L

2011-12-01

Ischiatic pressure sores are frequent in spinal cord injury patients, associated with bad prognosis and high recurrence rate. Many surgical techniques were described, including surgical debridement followed by pedicled flap coverage. We aim to propose a practical decision tree for primary or secondary ischial pressure sore treatment. Our series of 48 operated ischial sores with an average follow up of 4 years (range 2 to 8years) is analyzed and compared to previously published reports. Surgical techniques are discussed according to their specific indications. The optimal recurrence rate in published reports about pressure sore treatment is 20%; a rate inferior to 19% is found in our series, showing the equal importance of flap selection and postoperative care and education. Depending on each situation, various available flaps are described and compared: gluteus maximus flap, biceps femoris flap, gracilis flap, tensor fascia lata flap, fasciocutaneous thigh flaps, rectus femoris and vastus lateralis flap, rectus abdominis flap. Specific surgical indications for more extensive wounds are studied: resection arthroplasty of the hip, hip disarticulation, fillet flaps from the leg, microsurgery. Based upon our experience, a decision tree summarizes our proposition of flap selection, depending on the wound size and the patient background. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Reconstruction of the Foot and Ankle Using Pedicled or Free Flaps: Perioperative Flap Survival Analysis

PubMed Central

Li, Xiucun; Cui, Jianli; Maharjan, Suraj; Lu, Laijin; Gong, Xu

2016-01-01

Objective The purpose of this study is to determine the correlation between non-technical risk factors and the perioperative flap survival rate and to evaluate the choice of skin flap for the reconstruction of foot and ankle. Methods This was a clinical retrospective study. Nine variables were identified. The Kaplan-Meier method coupled with a log-rank test and a Cox regression model was used to predict the risk factors that influence the perioperative flap survival rate. The relationship between postoperative wound infection and risk factors was also analyzed using a logistic regression model. Results The overall flap survival rate was 85.42%. The necrosis rates of free flaps and pedicled flaps were 5.26% and 20.69%, respectively. According to the Cox regression model, flap type (hazard ratio [HR] = 2.592; 95% confidence interval [CI] (1.606, 4.184); P < 0.001) and postoperative wound infection (HR = 0.266; 95% CI (0.134, 0.529); P < 0.001) were found to be statistically significant risk factors associated with flap necrosis. Based on the logistic regression model, preoperative wound bed inflammation (odds ratio [OR] = 11.371,95% CI (3.117, 41.478), P < 0.001) was a statistically significant risk factor for postoperative wound infection. Conclusion Flap type and postoperative wound infection were both independent risk factors influencing the flap survival rate in the foot and ankle. However, postoperative wound infection was a risk factor for the pedicled flap but not for the free flap. Microvascular anastomosis is a major cause of free flap necrosis. To reconstruct complex or wide soft tissue defects of the foot or ankle, free flaps are safer and more reliable than pedicled flaps and should thus be the primary choice. PMID:27930679

Design of an antagonistic shape memory alloy actuator for flap type control surfaces

NASA Astrophysics Data System (ADS)

Dönmez, Burcu; Özkan, Bülent

2011-03-01

This paper deals with the flap control of unmanned aerial vehicles (UAVs) using shape memory alloy (SMA) actuators in an antagonistic configuration. The use of SMA actuators has the advantage of significant weight and cost reduction over the conventional actuation of the UAV flaps by electric motors or hydraulic actuators. In antagonistic configuration, two SMA actuators are used: one to rotate the flap clockwise and the other to rotate the flap counterclockwise. In this content, mathematical modeling of strain and power dissipation of SMA wire is obtained through characterization tests. Afterwards, the model of the antagonistic flap mechanism is derived. Later, based on these models both flap angle and power dissipation of the SMA wire are controlled in two different loops employing proportional-integral type and neural network based control schemes. The angle commands are converted to power commands through the outer loop controller later, which are updated using the error in the flap angle induced because of the indirect control and external effects. In this study, power consumption of the wire is introduced as a new internal feedback variable. Constructed simulation models are run and performance specifications of the proposed control systems are investigated. Consequently, it is shown that proposed controllers perform well in terms of achieving small tracking errors.

Measurement of the volume of the pedicled TRAM flap in immediate breast reconstruction.

PubMed

Chang, K P; Lin, S D; Hou, M F; Lee, S S; Tsai, C C

2001-12-01

The transverse rectus abdominis musculocutaneous (TRAM) flap is now accepted as the standard for breast reconstruction, but achieving symmetrical breast reconstruction is still a challenge. A precise estimate of the volume of the flap is necessary to reconstruct a symmetrical and aesthetically pleasing breast. Many methods have been developed to overcome this problem, but they have not been suitable for the pedicled TRAM flap. By using a self-made device based on the Archimedes' principle, the authors can calculate accurately the volume of the pedicled TRAM flap and predict reliably the breast volume intraoperatively. The "procedure" is based on a self-made box into which the pedicled TRAM flap is placed. Warm saline is added to the box and the flap is then removed. Flap volume is calculated easily by determining the difference between the preestimated volume of the box and the volume of the residual water. From February to May 2000, this method was used on 28 patients to predict breast volume for breast reconstruction. This study revealed that the difference of the maximal chest circumferences (the index of the breast volume) demonstrates a positive correlation with the difference of the volumes and weights between the mastectomy specimen and the net TRAM flap. However, a more closely positive correlation exists between the differences of maximal chest circumference volume (r = 0.677) than maximal chest circumference weight (r = 0.618). These data reveal that the reconstructed breast's volume has a closer relationship with the volume of the net pedicled TRAM flap, rather than with its weight.

Vascular anatomy of the supraclavicular area revisited: feasibility of the free supraclavicular perforator flap.

PubMed

Cordova, Adriana; Pirrello, Roberto; D'Arpa, Salvatore; Jeschke, Johannes; Brenner, Erich; Moschella, Francesco

2008-11-01

The supraclavicular skin has been studied extensively and used as a pedicled flap for face and neck reconstruction. Its use as a free flap has not paralleled its use as a pedicled flap. The authors performed an anatomical investigation to assess the possibility of harvesting a free supraclavicular flap with the donor-site scar lying in the supraclavicular crease. In this article, the authors present the results of their anatomical study together with the preliminary clinical applications. Skin vascularization and feasibility of a free supraclavicular perforator flap were studied on 25 cadavers (15 fresh cadavers injected with colored latex at the Universiteé René Descartes in Paris; and 10 formalin-fixed, noninjected cadavers at the Innsbruck Medical University). The flap was used in two patients at the Plastic Surgery Department of the University of Palermo for a cutaneous facial reconstruction and intraoral reconstruction after cancer excision. An average of four perforators were consistently found in the supraclavicular area coming from the transverse cervical artery. Venous perforators drain into the superficial venous plexus rather than into the venae comitantes of the transverse cervical artery. Two flaps were successfully used based on these vessels. The vascularization of the supraclavicular skin depends on skin perforators coming from the transverse cervical artery and draining into the superficial venous plexus. Based on these vessels, a reliable free supraclavicular flap seems to be safe to harvest, with the scar hidden in the supraclavicular crease. The preliminary clinical applications of such a flap gave promising results, suggesting its potential applications.

Design and testing of shape memory alloy actuation mechanism for flapping wing micro unmanned aerial vehicles

NASA Astrophysics Data System (ADS)

Kamaruzaman, N. F.; Abdullah, E. J.

2017-12-01

Shape memory alloy (SMA) actuator offers great solution for aerospace applications with low weight being its most attractive feature. A SMA actuation mechanism for the flapping micro unmanned aerial vehicle (MAV) is proposed in this study, where SMA material is the primary system that provides the flapping motion to the wings. Based on several established design criteria, a design prototype has been fabricated to validate the design. As a proof of concept, an experiment is performed using an electrical circuit to power the SMA actuator to evaluate the flapping angle. During testing, several problems have been observed and their solutions for future development are proposed. Based on the experiment, the average recorded flapping wing angle is 14.33° for upward deflection and 12.12° for downward deflection. This meets the required design criteria and objective set forth for this design. The results prove the feasibility of employing SMA actuators in flapping wing MAV.

Robust design of multiple trailing edge flaps for helicopter vibration reduction: A multi-objective bat algorithm approach

NASA Astrophysics Data System (ADS)

Mallick, Rajnish; Ganguli, Ranjan; Seetharama Bhat, M.

2015-09-01

The objective of this study is to determine an optimal trailing edge flap configuration and flap location to achieve minimum hub vibration levels and flap actuation power simultaneously. An aeroelastic analysis of a soft in-plane four-bladed rotor is performed in conjunction with optimal control. A second-order polynomial response surface based on an orthogonal array (OA) with 3-level design describes both the objectives adequately. Two new orthogonal arrays called MGB2P-OA and MGB4P-OA are proposed to generate nonlinear response surfaces with all interaction terms for two and four parameters, respectively. A multi-objective bat algorithm (MOBA) approach is used to obtain the optimal design point for the mutually conflicting objectives. MOBA is a recently developed nature-inspired metaheuristic optimization algorithm that is based on the echolocation behaviour of bats. It is found that MOBA inspired Pareto optimal trailing edge flap design reduces vibration levels by 73% and flap actuation power by 27% in comparison with the baseline design.

The Pedicled Buccal Fat Pad: Anatomical Study of the New Flap for Skull Base Defect Reconstruction After Endoscopic Endonasal Transpterygoid Surgery

PubMed Central

Golbin, Denis A.; Lasunin, Nikolay V.; Cherekaev, Vasily A.; Polev, Georgiy A.

2016-01-01

Objectives To evaluate the efficacy and safety of using a buccal fat pad for endoscopic skull base defect reconstruction. Design Descriptive anatomical study with an illustrative case presentation. Setting Anatomical study was performed on 12 fresh human cadaver specimens with injected arteries (24 sides). Internal carotid artery was exposed in the coronal plane via the endoscopic transpterygoid approach. The pedicled buccal fat pad was used for reconstruction. Participants: 12 human cadaver head specimens; one patient operated using the proposed technique. Main outcome measures: Proximity of the buccal fat pad flap to the defect, compliance of the flap, comfort and safety of harvesting procedure, and compatibility with the Hadad–Bassagasteguy nasoseptal flap. Results: Harvesting procedure was performed using anterior transmaxillary corridor. The pedicled buccal fat pad flap can be used to pack the sphenoid sinus or cover the internal carotid artery from cavernous to upper parapharyngeal segment. Conclusion The buccal fat pad can be safely harvested through the same approach without external incisions and is compliant enough to conform to the skull base defect. The proposed pedicled flap can replace free abdominal fat in central skull base reconstruction. The volume of the buccal fat pad allows obliteration of the sphenoid sinus or upper parapharyngeal space. PMID:28180047

Rectus femoris muscle flap based on proximal insertion mobilization to cover a groin infected vascular graft.

PubMed

Silvestre, Luís; Pedro, Luís Mendes; Fernandes e Fernandes, Ruy; Silva, Emanuel; Fernandes e Fernandes, José

2015-10-01

The rectus femoris (RF) muscle flap, which is widely used to cover groin infected vascular grafts, is usually harvested through distal tendon division and an extensive muscle elevation and transposition into the groin wound defect. A case of a vascular prosthetic graft infection in the groin was successfully controlled after coverage with an RF flap that was harvested based on proximal portion mobilization instead of the conventional distal one. This case suggests that the RF muscle flap based on proximal insertion mobilization is a feasible, effective, technically simpler, and less invasive alternative to cover infected vascular grafts in the groin. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Giant trochanteric pressure sore: Use of a pedicled chimeric perforator flap for cover

PubMed Central

Mehrotra, Sandeep

2009-01-01

Pressure sores are increasing in frequency commensurate with an ageing population with multi-system disorders and trauma. Numerous classic options are described for providing stable wound cover. With the burgeoning knowledge on perforator anatomy, recent approaches focus on the use of perforator-based flaps in bedsore surgery. A giant neglected trochanteric pressure sore in a paraplegic is presented. Since conventional options of reconstruction appeared remote, the massive ulcer was successfully managed by a chimeric perforator-based flap. The combined muscle and fasciocutaneous flaps were raised as separate paddles based on the anterolateral thigh perforator branches and provided stable cover without complications. Perforators allow versatility in managing complex wounds without compromising on established principles. PMID:19881035

The proximally based long peroneal muscle turnover flap: A novel salvage flap for small to medium-sized defects of the knee.

PubMed

Wagner, Till; Hupkens, Pieter; Slater, Nicholas J; Ulrich, Dietmar J O

2016-04-01

Coverage of soft-tissue defects of the knee due to multiple operations, trauma, and infection remains a surgical challenge. Often, these defects are repaired using free tissue transfer. The aim of this study was to find an easy and reliable local method of repair for small to medium-sized defects. The authors describe a new surgical option for tissue coverage using a proximally based long peroneal muscle turnover flap (LPTF) with split-thickness skin graft. Proximally based LPTFs were harvested and transposed into same-size created defects in five cadavers. After optimizing this technique, it was clinically used in two patients with defects secondary to total knee replacement revisions. Average cadaver flap size was 4.7 × 15.8 cm allowing reach of all knee joint areas and was based consistently on a sufficient (2-mm-diameter average) proximal arterial branch of the anterior tibial artery. Donor sites were closed without tension. Subsequent application of the flap on two patients resulted in good functional outcome. The proximally based LPTF is a new option available in the reconstruction of knee defects and should be added to the reconstructive surgeon's armamentarium of pedicled flaps, providing short operating time and promising clinical outcome. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Discovery of the first dual inhibitor of the 5-lipoxygenase-activating protein and soluble epoxide hydrolase using pharmacophore-based virtual screening

NASA Astrophysics Data System (ADS)

Temml, Veronika; Garscha, Ulrike; Romp, Erik; Schubert, Gregor; Gerstmeier, Jana; Kutil, Zsofia; Matuszczak, Barbara; Waltenberger, Birgit; Stuppner, Hermann; Werz, Oliver; Schuster, Daniela

2017-02-01

Leukotrienes (LTs) are pro-inflammatory lipid mediators derived from arachidonic acid (AA) with roles in inflammatory and allergic diseases. The biosynthesis of LTs is initiated by transfer of AA via the 5-lipoxygenase-activating protein (FLAP) to 5-lipoxygenase (5-LO). FLAP inhibition abolishes LT formation exerting anti-inflammatory effects. The soluble epoxide hydrolase (sEH) converts AA-derived anti-inflammatory epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatetraenoic acids (di-HETEs). Its inhibition consequently also counteracts inflammation. Targeting both LT biosynthesis and the conversion of EETs with a dual inhibitor of FLAP and sEH may represent a novel, powerful anti-inflammatory strategy. We present a pharmacophore-based virtual screening campaign that led to 20 hit compounds of which 4 targeted FLAP and 4 were sEH inhibitors. Among them, the first dual inhibitor for sEH and FLAP was identified, N-[4-(benzothiazol-2-ylmethoxy)-2-methylphenyl]-N’-(3,4-dichlorophenyl)urea with IC50 values of 200 nM in a cell-based FLAP test system and 20 nM for sEH activity in a cell-free assay.

Distally Based Sural Artery Peroneus Flap (DBSPF) for Foot and Ankle Reconstruction

PubMed Central

Ebrahiem, Ahmed Ali; Manas, Raj Kumar

2017-01-01

Background: Reconstruction of soft-tissue defects in lower third of leg, ankle, and foot has been a challenge and reconstructive surgeons have been trying to innovate different flaps. To solve this issue, we propose a distally based sural artery peroneus flap (DBSPF) in which we include superficial portion of the peroneus brevis muscle and its blood supply with the peroneal artery distally. The aim of this study was to evaluate the functional outcome and its usefulness over conventional distal sural artery flap or other local options available. Methods: This is a case series of 20 patients that include a DBSPF that was done for defects around ankle, distal leg, and foot caused by trauma or tumor ablation within the period of June 2013 to March 2015 in Kasralainy Hospital, Cairo. All cases were evaluated according to flap vascularity, distal reach of flap, aesthetic outcome, and donor-site morbidity. Results: All flaps survived. One flap developed venous congestion that subsided spontaneously with limb elevation. The flap dimension ranged from 42 cm to 442 cm2, and it reached the midfoot easily. The pivot point was kept as low as 2–6 cm from lateral malleolus according to location of perforators. The ankle stability was maintained, and the desired aesthetic outcome was achieved. Conclusions: The DBSPF is an addition to the armamentarium in plastic surgery for defects around ankle, distal leg, and foot. It is an easy and swift procedure as compared with complex microsurgical reconstruction. PMID:28507850

Versatility of the Angularis Oris Axial Pattern Flap for Facial Reconstruction.

PubMed

Losinski, Sara L; Stanley, Bryden J; Schallberger, Sandra P; Nelson, Laura L; Towle Millard, Heather A M

2015-11-01

To describe the versatility of the axial pattern flap based on the cutaneous perforating branch of the angularis oris artery for reconstruction of large facial defects in dogs, including complications and clinical outcomes. Retrospective clinical case series. Client-owned dogs (n = 8). Facial flaps (n = 9) based at the commissure of the lip with a caudodorsal orientation were utilized, with established anatomical borders. Flaps were elevated deep to the panniculus carnosus in a caudal to rostral direction, preserving the angularis oris artery, its cutaneous perforator, and surrounding cutaneous vasculature. Flaps were rotated dorsally or ventrally to cover the defect. Primary closure of the donor site was by direct apposition in all cases. Angularis oris axial pattern flaps were most commonly used to close large defects of the nasomaxillary area rostral to the eyes (6 dogs), followed by orbital (2) and intermandibular (1) defects. Defects occurred because of tumor resection (6 dogs), trauma (2), and a chronic, non-healing wounding (1). All flaps healed with acceptable functional and cosmetic outcomes without major complications. Followup ranged from 10 days to 16 months. Minor postoperative complications included flap edema (8 dogs), partial incisional dehiscence (3), distal tip necrosis (2), and oroantral fistula recurrence (1). Angularis oris axial pattern flaps provided hirsute, full-thickness skin coverage of a variety of large facial defects with minor complications, and should be considered when restructuring large defects of the rostral face or chin. © Copyright 2015 by The American College of Veterinary Surgeons.

A Novel Perforator Flap Training Model Using a Chicken Leg

PubMed Central

Cifuentes, Ignacio J.; Yañez, Ricardo A.; Salisbury, Maria C.; Rodriguez, José R.; Varas, Julian E.; Dagnino, Bruno L.

2016-01-01

Introduction  Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. Methods  A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. Results  The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. Conclusion  This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training. PMID:27616823

Total Reconstruction of Lower Eyelid in a Post-traumatic Patient Using Modified Fricke's Cheek Flap.

PubMed

Sengupta, Subhabrata; Baruah, Binayak; Pal, Suvra; Tuli, Isha Preet

2013-07-01

Eyelids are very complex structure, reconstruction of which is a challenge to surgeons. Reconstruction of eyelids may be required in a variety of conditions like congenital anomalies, trauma, or postsurgical excision in malignant lesions involving the eyelids. There are numerous ways to reconstruct the eyelids; the best procedure depends on both the skill of the surgeon and the condition of the patient. Fricke' lateral temporal based flap was first described in 1829 for reconstruction of the eyelids and lateral canthal region. This flap had inherent problems regarding cosmetic appearance of the eyebrows. The modified Fricke's flap based on the cheek has the advantage of avoiding such complications. It is very easy and rapid outpatient department (OPD) based procedure with acceptable cosmetic and functional result. It can be done by all ear, nose, and throat (ENT) and head and neck surgeons without any reconstructive training. In this article we are presenting a case of total reconstruction of lower eyelid using the modified Fricke's cheek flap.

Modified trans-oral approach with an inferiorly based flap.

PubMed

Al-Holou, Wajd N; Park, Paul; Wang, Anthony C; Than, Khoi D; Marentette, Lawrence J

2010-04-01

The trans-oral approach allows direct access to pathologies of the anterior craniocervical junction. However, the classic midline incision of the posterior pharyngeal wall can be surgically burdensome and limits lateral exposure. We reviewed the medical records of nine patients undergoing the trans-oral approach. The sites of the pathology ranged from the clivus to C2, and surgical exposure ranged from the clivus to C3. Each operation utilized an inferiorly based flap. None of the patients experienced vascular or neurologic complications, and no patient had a cerebrospinal fluid fistula, pseudomeningocele, or meningitis postoperatively. The trans-oral approach with an inferiorly based flap can therefore be safely and effectively performed with minimal oropharyngeal and neurologic morbidity. Not only does a U-shaped flap allow adequate exposure from the lower half of the clivus to C3, a flap improves lateral exposure, provides a clear operating field, and allows superficial mucosal closure not directly overlying the operative field. (c) 2009 Elsevier Ltd. All rights reserved.

A novel animal model for skin flap prelamination with biomaterials

NASA Astrophysics Data System (ADS)

Zhou, Xianyu; Luo, Xusong; Liu, Fei; Gu, Chuan; Wang, Xi; Yang, Qun; Qian, Yunliang; Yang, Jun

2016-09-01

Several animal models of skin flap construction were reported using biomaterials in a way similar to prefabrication. However, there are few animal model using biomaterials similar to prelamination, another main way of clinical skin flap construction that has been proved to be reliable. Can biomaterials be added in skin flap prelamination to reduce the use of autogenous tissues? Beside individual clinical attempts, animal model is needed for randomized controlled trial to objectively evaluate the feasibility and further investigation. Combining human Acellular Dermal Matrix (hADM) and autologous skin graft, we prelaminated flaps based on inguinal fascia. One, two, three and four weeks later, hADM exhibited a sound revascularization and host cell infiltration. Prelaminated skin flaps were then raised and microsurgically transplanted back to groin region. Except for flaps after one week of prelamination, flaps from other subgroups successfully reconstructed defects. After six to sixteen weeks of transplantation, hADM was proved to being able to maintain its original structure, having a wealth of host tissue cells and achieving full revascularization.To our knowledge, this is the first animal model of prelaminating skin flap with biomaterials. Success of this animal model indicates that novel flap prelamination with biomaterials is feasible.

Reconstruction of trochanteric pressure sores with pedicled anterolateral thigh myocutaneous flaps.

PubMed

Wang, Chih-Hsin; Chen, Shih-Yi; Fu, Ju-Peng; Dai, Niann-Tzyy; Chen, Shao-Liang; Chen, Tim-Mo; Chen, Shyi-Gen

2011-05-01

To provide an alternative choice for covering trochanteric pressure sores, we report on a modified pedicle anterolateral thigh (ALT) myocutaneous flap based on the descending branch of the lateral circumflex femoral artery. From August 2007 to January 2010, 20 consecutive patients (10 men and 10 women) underwent 21 pedicled ALT myocutaneous flaps for reconstruction of trochanteric pressure sores. The flap was designed and elevated, resembling the ALT perforator flap including part of the vastus lateralis muscle but without skeletonisation of the perforators. The mean age of patients was 79.4 years (range: 46-103). The mean follow-up period was 13.9 months (range: 3-32). The flaps were 8-21 cm long and 5-11 cm wide. All flaps healed without major complications. All donor sites were closed primarily without skin grafting and showed good aesthetic results. No recurrence was observed. This modified design of pedicled ALT myocutaneous flap without skeletonisation of perforators is a reliable and easily harvested flap for reconstruction of trochanteric pressure sores with limited morbidity. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Medium- and Large-Sized Autologous Breast Reconstruction using a Fleur-de-lys Profunda Femoris Artery Perforator Flap Design: A Report Comparing Results with the Horizontal Profunda Femoris Artery Perforator Flap.

PubMed

Hunsinger, Vincent; Lhuaire, Martin; Haddad, Kevin; Wirz, Francesco-Saverio; Abedalthaqafi, Samah; Obadia, Déborah; Derder, Mohamed; Marchac, Alexandre; Benjoar, Marc David; Hivelin, Mikael; Lantieri, Laurent

2018-06-02

 The volume of the profunda femoris artery perforator (PAP) flap limits its indications to small- and medium-sized breast reconstructions after modified radical mastectomy for cancer. We report a modified PAP flap design, including not only a vertical extension that increases its volume but also the skin surface, which suits larger breasts requiring immediate or delayed breast reconstructions and compare the results with our horizontal skin paddle PAP flap experience.  In our center between November 2014 and November 2016, 51 consecutive patients underwent a PAP flap breast reconstruction following breast cancer. A retrospective analysis on the collected data was performed to compare 34 patients with a bra cup smaller than C who underwent 41 horizontal PAP flap procedures, with those ( n  = 17) of a bra cup greater than or equal to C who underwent 21 fleur-de-lys PAP flap procedures. Demographic, anthropometric, flap and surgical characteristics, postoperative complication rates, and hospital stay were compared between the two groups.  The average flap weight was 480 g (range: 340-735 g) for the fleur-de-lys PAP flap group compared with 222 g (range: 187-325 g) for the horizontal PAP flap procedure ( p  < 0.001). The mean flap dimensions were 25 × 18 cm for the fleur-de-lys PAP flap group compared with 25 × 7 cm in the horizontal PAP flap group. No flap failure was observed in the fleur-de-lys PAP flap group compared with two flap failures secondary to venous thrombosis in the horizontal PAP flap group ( NS ). Three patients (14%) experienced delayed healing at the donor site compared with four patients (10%) in the horizontal PAP flap group ( NS ).  The fleur-de-lys skin paddle design not only allows an increase of the horizontal PAP flap volume, but also increases the skin surface, with an acceptable donor site morbidity. For medium- or large-sized breasts, the fleur-de-lys PAP flap seems to be ideal when a DIEP flap-based reconstruction is contraindicated. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Calf Perforator Flaps: A Freestyle Solution for Oral Cavity Reconstruction.

PubMed

Molina, Alexandra R; Citron, Isabelle; Chinaka, Fungayi; Cascarini, Luke; Townley, William A

2017-02-01

Reconstruction of oral cavity defects requires a thin, pliable flap for optimal functional results. Traditional flap choices are imperfect: the anterolateral thigh flap is excessively thick, whereas the radial forearm flap has a poor donor site. The authors therefore favor calf perforator flaps such as the medial sural artery perforator flap to provide thin tissue with an acceptable donor site. This two-part study aims to demonstrate their suitability for intraoral reconstruction. In the radiologic part of the study, the authors compared thigh and calf tissue thickness by examining lower limb computed tomographic scans of 100 legs. For their clinical study, they collected data prospectively on 20 cases of oral cavity reconstruction using calf perforator flaps. The mean thickness of the calf tissue envelope was significantly less than that of the thigh (8.4 mm compared with 17 mm) based on computed tomographic analysis. In the clinical study, a medial sural artery perforator was used in the majority of cases (17 of 20). The mean pedicle length was 10.2 cm and the mean time to raise a flap was 85 minutes. There were no flap losses. One patient was returned to the operating room for management of late hematoma and wound dehiscence. Calf perforator flaps provide ideal tissue for intraoral reconstruction and are significantly thinner than anterolateral thigh flaps. In addition to medial sural artery perforator flaps, the authors raised both sural and soleal artery perforator flaps in this series. Opportunistic use of the calf donor site allows the harvest of thin tissue with minimal donor-site morbidity. Therapeutic, IV.

Sternocleidomastoid myofascial flap for reconstruction after composite resection of invasive squamous cell carcinoma of the tonsillar region: technique and outcome.

PubMed

Laccourreye, Ollivier; Ménard, Madeleine; Behm, Eva; Garcia, Dominique; Cauchois, Régis; Holsinger, F Christopher

2006-11-01

To present the surgical technique and determine the efficacy of sternocleidomastoid myofascial (SCMF) flap reconstruction after composite resection with intent to cure. Retrospective review of 73 consecutive patients with a previously isolated and untreated moderately to well-differentiated invasive squamous cell carcinoma of the tonsillar region and a minimum of 3 years follow-up, managed at a tertiary referral care center during the years 1970 to 2002, with an ipsilateral superiorly based SCMF flap after composite resection. The surgical procedure is presented in detail. Potential technical pitfalls are highlighted. Survival, mortality, and morbidity are documented. Univariate analysis for potential correlation between the incidence for postoperative flap complications and various variables is also performed. The 1, 3, and 5 year Kaplan-Meier actuarial survival estimates were 82.2%, 64.4%, and 49.3%, respectively. Death never appeared to be related to the completion of the SCMF flap. Thirty-three (45.2%) patients had some kind of significant postoperative surgical complication, and nine (12.3%) patients had some kind of significant postoperative medical complication. The most common significant postoperative complication was partial SCMF flap necrosis and pharyngocutaneous fistula noted in 30.1% and 10.9% of patients, respectively. Complete SCMF flap necrosis was never encountered. No patient developed carotid artery rupture or died as a result of the SCMF flap, and none required additional surgery. In univariate analysis, no significant statistical relation was noted between the significant postoperative surgical complications related to the use of the SCMF flap and the variables under analysis. The superiorly based SCMF flap appears to be simple to perform and useful for reconstruction of defects after composite resection.

Preoperative color Doppler assessment in planning of gluteal perforator flaps.

PubMed

Isken, Tonguc; Alagoz, M Sahin; Onyedi, Murat; Izmirli, Hakki; Isil, Eda; Yurtseven, Nagehan

2009-02-01

Gluteal artery perforator flaps have gained popularity due to reliability, preservation of the muscle, versatility in flap design without restricting other flap options, and low donor-site morbidity in ambulatory patients and possibility of enabling future reconstruction in paraplegic patients. But the inconstant anatomy of the vascular plexus around the gluteal muscle makes it hard to predict how many perforators are present, what their volume of blood flow and size are, where they exit the overlying fascia, and what their course through the muscle will be. Without any prior investigations, the reconstructive surgeon could be surprised intraoperatively by previous surgical damage, scar formation, or anatomic variants.For these reasons, to confirm the presence and the location of gluteal perforators preoperatively we have used color Doppler ultrasonography. With the help of the color Doppler ultrasonography 26 patients, 21 men and 5 women, were operated between the years 2002 and 2007. The mean age of patients was 47.7 (age range: 7-77 years). All perforator vessels were marked preoperatively around the defect locations. The perforator based flap that will allow primary closure of the donor site and the defect without tension was planned choosing the perforator that showed the largest flow in color Doppler ultrasonography proximally. Perforators were found in the sites identified with color Doppler ultrasonography in all other flaps. In our study, 94.4% flap viability was ensured in 36 perforator-based gluteal area flaps. Mean flap elevation time was 31.9 minutes. We found that locating the perforators preoperatively helps to shorten the operation time without compromising a reliable viability of the perforator flaps, thus enabling the surgeon easier treatment of pressure sores.

Analysis of a Multi-Flap Control System for a Swashplateless Rotor

NASA Technical Reports Server (NTRS)

Sekula, Martin K.; Wilbur, Matthew L.

2011-01-01

An analytical study was conducted examining the feasibility of a swashplateless rotor controlled through two trailing edge flaps (TEF), where the cyclic and collective controls were provided by separate TEFs. This analysis included a parametric study examining the impact of various design parameters on TEF deflections. Blade pitch bearing stiffness; blade pitch index; and flap chord, span, location, and control function of the inboard and outboard flaps were systematically varied on a utility-class rotorcraft trimmed in steady level flight. Gradient-based optimizations minimizing flap deflections were performed to identify single- and two-TEF swashplateless rotor designs. Steady, forward and turning flight analyses suggest that a two-TEF swashplateless rotor where the outboard flap provides cyclic control and inboard flap provides collective control can reduce TEF deflection requirements without a significant impact on power, compared to a single-TEF swashplateless rotor design.

Combined bilateral hatchet and nasolabial advancement flaps for a large defect of the lower lip.

PubMed

Makiguchi, Takaya; Yokoo, Satoshi; Miyazaki, Hidetaka; Soda, Takashi; Terashi, Hiroto

2013-11-01

A large full-thickness defect of the lower lip is difficult to reconstruct. Preservation of eating and speaking functions based on maintenance of oral sphincter and muscle function, sensation, and the oral aperture are the basic aims. It is also important to achieve a good aesthetic appearance. Here, we describe a new procedure using combined bilateral hatchet and nasolabial advancement flaps for a large full-thickness defect of the lower lip. The aim of use of the hatchet flap is to make a natural curve from the mentolabial fold to the mental protuberance using the "dog ear" resulting from suturing medially advanced bilateral hatchet flaps and to preserve a more certain blood supply to the medial edge of the flap. Our results indicate that the procedure using combined bilateral hatchet flaps and nasolabial flaps is useful for a U-shaped large full-thickness defect, with good functional and aesthetic outcomes.

Use of Pericranial Flaps in the Management of Cranial Base Trauma

PubMed Central

Polley, John W.; Penney, Don; Cohen, Mimis

1993-01-01

Pericranial flaps based on the musuloaponeurotic or myofacial layers of the scalp have great utility in the management of acquired and congenital craniofacial deformities. Their use in traumatic deformities is indicated in the presence of craniopharyngeal communications and significant anterior cranial fossa dead space created from frontal sinus obliteration. The indications and operative techniques and the results of the use of these flaps in 10 consecutive patient with extensive cranial base trauma are presented. ImagesFigure 4p49-bFigure 4Figure 5Figure 5p52-b PMID:17170889

Flapping, wobbling, and zig-zagging: Tomographic PIV measurements of Antarctic sea butterfly ``flying'' underwater

NASA Astrophysics Data System (ADS)

Adhikari, D.; Webster, D. R.; Yen, J.

2015-11-01

A portable tomographic PIV technique was used to study the fluid dynamics and kinematics of sea butterflies in Antarctica. Antarctic pteropods (or sea butterflies), which are currently threatened by ocean acidification, swim in seawater with a pair of gelatinous parapodia (or ``wings'') via a unique propulsion mechanism. Both power and recovery strokes propel the organism (1.5 - 5 mm in size) upward in a sawtooth-like trajectory with average speed of 14 - 30 mm/s and pitch the shell forwards-and-backwards at 1.9 - 3 Hz. The pitching motion effectively positions the parapodia such that they stroke downward during both the power and recovery strokes. Reynolds numbers defined for flapping, translating, and pitching (i.e. Ref, ReU, and ReΩ) characterize the motion of the pteropod. For Ref <50, the shell does not pitch and the pteropod swims abnormally. We present a detailed comparison of the volumetric fluid velocity fields induced by pteropods swimming upwards with Ref = 80 and 180. The pteropod at the lower Ref creates an attached shear flow along the parapodia and pushes fluid in a method analogous to a paddle. In contrast, at higher Ref, the flow along the parapodia separates and generates complex vortex structures.

The midline central artery forehead flap: a valid alternative to supratrochlear-based forehead flaps.

PubMed

Faris, Callum; van der Eerden, Paul; Vuyk, Hade

2015-01-01

This study clarifies the pedicle geometry and vascular supply of a midline forehead flap for nasal reconstruction. It reports on the vascular reliability of this flap and its ability to reduce hair transposition to the nose, a major complicating factor of previous forehead flap designs. To compare the vascular reliability of 3 different pedicle designs of the forehead flap in nasal reconstruction (classic paramedian, glabellar paramedian, and central artery flap design) and evaluate hair transposition rates and aesthetic results. Retrospective analysis of patient data and outcomes retrieved from computer files generated at the time of surgery, supplemented by data from the patient medical records and photographic documentation, from a tertiary referral nasal reconstructive practice, within a secondary-care hospital setting. The study population included all consecutive patients over a 19-year period who underwent primary forehead flap repair of nasal defects, with more than 3 months of postoperative follow-up and photographic documentation. Three sequential forehead flap patterns were used (classic paramedian flap, glabella flap, and central artery flap) for nasal reconstruction over the study duration. Data collected included patient characteristics, method of repair, complications, functional outcome, and patient satisfaction score. For cosmetic outcome, photographic documentation was scored by a medical juror. No forehead flap had vascular compromise in the first stage. Partial flap necrosis was reported in subsequent stages in 4 patients (1%), with no statistical difference in the rate of vascular compromise between the 3 flap designs. Hair transposition to the nose was lower in the central artery forehead flap (7%) compared with the classic paramedian (23%) and glabellar paramedian (13%) flaps (P < .05). Photographic evaluation in 227 patients showed that brow position (98%) and color match (83%) were good in the majority of the patients. In this series, the central artery forehead flap was as reliable (in terms of vascularity) as the glabellar and classic paramedian forehead flap. Its use resulted in a statistically significant reduction in transfer of hair to the nose in our series. 3.

Tessier No. 3 and No. 4 clefts: Sequential treatment in infancy by pre-surgical orthopedic skeletal contraction, comprehensive reconstruction, and novel surgical lengthening of the ala base-canthal distance.

PubMed

Spolyar, John L; Hnatiuk, Mark; Shaheen, Kenneth W; Mertz, Jennifer K; Handler, Lawrence F; Jarial, Ravinder; Roldán, J Camilo

2015-09-01

Repair of facial clefts implies wide tissue mobilization with multi-stage surgical treatment. Authors propose pre-surgical orthopedic correction for naso-oro-ocular clefts and a novel surgical option for Tessier No. 3 cleft. Two male infants, a Tessier No. 3 cleft (age 7 months) and another Tessier No. 4 (age 3 months), were treated with a modified orthopedic Latham device with additional septo-premaxillary molding and observed to age four years. Tessier No. 3 orthopedic measurements were obtained by image corrected cephalometric analysis. Subsequent repair included tissue expansion on Tessier No. 4 and naso-frontal Rieger flap combined with myocutaneous upper lid flap on Tessier No. 3. Orthopedic movements ranged from 18.5 mm in bi-planar to 33 mm in oblique analyses. Tissue margins became aligned with platform normalization. Tissue expansion on Tessier No. 4 improved distances from ala base-lower lid and subalar base-lip. The naso-frontal flap combined with myocutaneous upper lid flap on Tessier No. 3 had similar achievement, but also sufficiently lengthened ala base-canthal distance. Repairs were facilitated by pre-surgical orthopedic correction. The naso-frontal flap combined with an upper lid myocutaneous flap seems viable as a single-stage option to lengthen ala base-canthal distance to advance repair achievement in unilateral Tessier No. 3. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Spacecraft compartment venting

NASA Astrophysics Data System (ADS)

Scialdone, John J.

1998-10-01

At various times, concerns have been expressed that rapid decompressions of compartments of gas pockets and thermal blankets during spacecraft launches may have caused pressure differentials across their walls sufficient to cause minor structural failures, separations of adhesively-joined parts, ballooning, and flapping of blankets. This paper presents a close form equation expressing the expected pressure differentials across the walls of a compartment as a function of the external to the volume pressure drops, the pressure at which the rates occur and the vent capability of the compartment. The pressure profiles measured inside the shrouds of several spacecraft propelled by several vehicles and some profiles obtained from ground vacuum systems have been included. The equation can be used to design the appropriate vent, which will preclude excessive pressure differentials. Precautions and needed approaches for the evaluations of the expected pressures have been indicated. Methods to make a rapid assessment of the response of the compartment to rapid external pressure drops have been discussed. These are based on the evaluation of the compartment vent flow conductance, the volume and the length of time during which the rapid pressure drop occurs.

Spacecraft Compartment Venting

NASA Technical Reports Server (NTRS)

Scialdone, John J.

1998-01-01

At various time concerns have been expressed that rapid decompressions of compartments of gas pockets and thermal blankets during spacecraft launches may have caused pressure differentials across their walls sufficient to cause minor structural failures, separations of adhesively-joined parts, ballooning, and flapping of blankets. This paper presents a close form equation expressing the expected pressure differentials across the walls of a compartment as a function of the external to the volume pressure drops, the pressure at which the rates occur and the vent capability of the compartment. The pressure profiles measured inside the shrouds of several spacecraft propelled by several vehicles and some profiles obtained from ground vacuum systems have been included. The equation can be used to design the appropriate vent, which will preclude excessive pressure differentials. Precautions and needed approaches for the evaluations of the expected pressures have been indicated. Methods to make a rapid assessment of the response of the compartment to rapid external pressure drops have been discussed. These are based on the evaluation of the compartment vent flow conductance, the volume and the length of time during which the rapid pressure drop occurs.

Fish robotics and hydrodynamics

NASA Astrophysics Data System (ADS)

Lauder, George

2010-11-01

Studying the fluid dynamics of locomotion in freely-swimming fishes is challenging due to difficulties in controlling fish behavior. To provide better control over fish-like propulsive systems we have constructed a variety of fish-like robotic test platforms that range from highly biomimetic models of fins, to simple physical models of body movements during aquatic locomotion. First, we have constructed a series of biorobotic models of fish pectoral fins with 5 fin rays that allow detailed study of fin motion, forces, and fluid dynamics associated with fin-based locomotion. We find that by tuning fin ray stiffness and the imposed motion program we can produce thrust both on the fin outstroke and instroke. Second, we are using a robotic flapping foil system to study the self-propulsion of flexible plastic foils of varying stiffness, length, and trailing edge shape as a means of investigating the fluid dynamic effect of simple changes in the properties of undulating bodies moving through water. We find unexpected non-linear stiffness-dependent effects of changing foil length on self-propelled speed, and as well as significant effects of trailing edge shape on foil swimming speed.

Kinematic Optimization in Birds, Bats and Ornithopters

NASA Astrophysics Data System (ADS)

Reichert, Todd

Birds and bats employ a variety of advanced wing motions in the efficient production of thrust. The purpose of this thesis is to quantify the benefit of these advanced wing motions, determine the optimal theoretical wing kinematics for a given flight condition, and to develop a methodology for applying the results in the optimal design of flapping-wing aircraft (ornithopters). To this end, a medium-fidelity, combined aero-structural model has been developed that is capable of simulating the advanced kinematics seen in bird flight, as well as the highly non-linear structural deformations typical of high-aspect ratio wings. Five unique methods of thrust production observed in natural species have been isolated, quantified and thoroughly investigated for their dependence on Reynolds number, airfoil selection, frequency, amplitude and relative phasing. A gradient-based optimization algorithm has been employed to determined the wing kinematics that result in the minimum required power for a generalized aircraft or species in any given flight condition. In addition to the theoretical work, with the help of an extended team, the methodology was applied to the design and construction of the world's first successful human-powered ornithopter. The Snowbird Human-Powered Ornithopter, is used as an example aircraft to show how additional design constraints can pose limits on the optimal kinematics. The results show significant trends that give insight into the kinematic operation of natural species. The general result is that additional complexity, whether it be larger twisting deformations or advanced wing-folding mechanisms, allows for the possibility of more efficient flight. At its theoretical optimum, the efficiency of flapping-wings exceeds that of current rotors and propellers, although these efficiencies are quite difficult to achieve in practice.

Management of Unfavorable Outcomes in Head and Neck Free Flap Reconstruction: Experience-Based Lessons from the MD Anderson Cancer Center.

PubMed

Chang, Edward I; Hanasono, Matthew M; Butler, Charles E

2016-10-01

Complex head and neck reconstruction often mandates free tissue transfer to achieve the most optimal outcomes. Unfortunately, such challenging cases are not without risks of complications, the most dreaded of which is loss of the free flap. Aside from loss of the free flap, there are several other potential complications that can result following head and neck reconstruction. Certain complications are avoided with careful planning, others require significant revisions and in certain cases another free flap. This article presents the experience managing a series of unique complications following free flap head and neck reconstruction. Published by Elsevier Inc.

Reconstruction of posterior neck and skull with vertical trapezius musculocutaneous flap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathes, S.J.; Stevenson, T.R.

1988-10-01

The vertical trapezius musculocutaneous flap has been successfully utilized for reconstruction in 13 patients with complex posterior skull and neck defects. This flap based on its vascular pedicle, the descending branch of the transverse cervical artery, provides well-vascularized tissue for coverage of defects related to chronic osteomyelitis, tumor extirpation, osteoradionecrosis, and dehisced cervical laminectomy wounds. Emphasis on flap design, including the location of the skin island, allows adequate wound coverage, direct donor site closure, and muscle function preservation. With its large size and wide arc of rotation, the vertical trapezius musculocutaneous flap provides reliable coverage for posterior trunk, cervical, andmore » skull defects.« less

4D metrology of flapping-wing micro air vehicle based on fringe projection

NASA Astrophysics Data System (ADS)

Zhang, Qican; Huang, Lei; Chin, Yao-Wei; Keong, Lau-Gih; Asundi, Anand

2013-06-01

Inspired by dominant flight of the natural flyers and driven by civilian and military purposes, micro air vehicle (MAV) has been developed so far by passive wing control but still pales in aerodynamic performance. Better understanding of flapping wing flight mechanism is eager to improve MAV's flight performance. In this paper, a simple and effective 4D metrology technique to measure full-field deformation of flapping membrane wing is presented. Based on fringe projection and 3D Fourier analysis, the fast and complex dynamic deformation, including wing rotation and wing stroke, of a flapping wing during its flight can be accurately reconstructed from the deformed fringe patterns recorded by a highspeed camera. An experiment was carried on a flapping-wing MAV with 5-cm span membrane wing beating at 30 Hz, and the results show that this method is effective and will be useful to the aerodynamicist or micro aircraft designer for visualizing high-speed complex wing deformation and consequently aid the design of flapping wing mechanism to enhanced aerodynamic performance.

Logarithmic spiral flap for circular or oval defects on the lateral surface of the nose and nasal ala: a series of 15 cases.

PubMed

Moreno-Artero, E; Redondo, P

2015-10-01

A large number of flaps, particularly rotation and transposition flaps, have been described for the closure of skin defects left by oncologic surgery of the nose. The logarithmic spiral flap is a variant of the rotation flap. We present a series of 15 patients with different types of skin tumor on the nose. The skin defect resulting from excision of the tumor by micrographic surgery was reconstructed using various forms of the logarithmic spiral flap. There are 3 essential aspects to flap design: commencement of the pedicle at the upper or lower border of the wound, a width of the distal end of the flap equal to the vertical diameter of the defect, and a progressive increase in the radius of the spiral from the distal end of the flap to its base. The cosmetic and functional results of surgical reconstruction were satisfactory, and no patient required additional treatment to improve scar appearance. The logarithmic spiral flap is useful for the closure of circular or oval defects situated on the lateral surface of the nose and nasal ala. The flap initiates at one of the borders of the wound as a pedicle with a radius that increases progressively to create a spiral. We propose the logarithmic spiral flap as an excellent option for the closure of circular or oval defects of the nose. Copyright © 2015 Elsevier España, S.L.U. and AEDV. All rights reserved.

"All-laser" endothelial corneal transplant in human patients

NASA Astrophysics Data System (ADS)

Rossi, Francesca; Menabuoni, Luca; Malandrini, Alex; Canovetti, Annalisa; Lenzetti, Ivo; Pini, Roberto

2012-03-01

Femtosecond laser sculpturing of corneal tissue is commonly used for the preparation of endothelial flaps. Diode laser welding of ocular tissues is a procedure that enables minimally invasive suturing of tissues. The combination of these laser based techniques results in a new approach to minimally invasive ophthalmic surgery, such as in endothelial corneal transplant (or endothelial keratoplasty - EK). In this work we present the "all laser" EK performed in human subjects. 24 pseudophakic patients with bullous keratopathy underwent EK: the femtosecond laser was used to prepare the 100 ìm thick and 8.5 mm diameter donor Descemet endothelial flap. After staining the stromal layer of the donor flap with a liquid ICG solution, the donor flap was inserted in the recipient eye by the use of the Busin injector. Then, the endothelial layer was laser-welded to the recipient eye (10 laser spots around the periphery of the flap), in order to reduce the risk of postoperative dislocation of the transplanted flap. A transplanted flap engraftment was observed in all the treated eyes. The staining procedure used to perform laser welding also enabled to evidence the stromal side of the donor flap, so as the flap was always placed in the right side position. The endothelial cells counts in both the laserwelded flaps and in a control group were in good agreement. The proposed technique is easy to perform and enables the reduction of postoperative endothelial flap dislocations.

Panorama of Reconstruction of Skull Base Defects: From Traditional Open to Endonasal Endoscopic Approaches, from Free Grafts to Microvascular Flaps

PubMed Central

Reyes, Camilo; Mason, Eric; Solares, C. Arturo

2014-01-01

Introduction A substantial body of literature has been devoted to the distinct characteristics and surgical options to repair the skull base. However, the skull base is an anatomically challenging location that requires a three-dimensional reconstruction approach. Furthermore, advances in endoscopic skull base surgery encompass a wide range of surgical pathology, from benign tumors to sinonasal cancer. This has resulted in the creation of wide defects that yield a new challenge in skull base reconstruction. Progress in technology and imaging has made this approach an internationally accepted method to repair these defects. Objectives Discuss historical developments and flaps available for skull base reconstruction. Data Synthesis Free grafts in skull base reconstruction are a viable option in small defects and low-flow leaks. Vascularized flaps pose a distinct advantage in large defects and high-flow leaks. When open techniques are used, free flap reconstruction techniques are often necessary to repair large entry wound defects. Conclusions Reconstruction of skull base defects requires a thorough knowledge of surgical anatomy, disease, and patient risk factors associated with high-flow cerebrospinal fluid leaks. Various reconstruction techniques are available, from free tissue grafting to vascularized flaps. Possible complications that can befall after these procedures need to be considered. Although endonasal techniques are being used with increasing frequency, open techniques are still necessary in selected cases. PMID:25992142

Flight test operations using an F-106B research airplane modified with a wing leading-edge vortex flap

NASA Technical Reports Server (NTRS)

Dicarlo, Daniel J.; Brown, Philip W.; Hallissy, James B.

1992-01-01

Flight tests of an F-106B aircraft equipped with a leading-edge vortex flap, which represented the culmination of a research effort to examine the effectiveness of the flap, were conducted at the NASA Langley Research Center. The purpose of the flight tests was to establish a data base on the use of a wing leading-edge vortex flap as a means to validate the design and analysis methods associated with the development of such a vortical flow-control concept. The overall experiment included: refinements of the design codes for vortex flaps; numerous wind tunnel entries to aid in verifying design codes and determining basic aerodynamic characteristics; design and fabrication of the flaps, structural modifications to the wing tip and leading edges of the test aircraft; development and installation of an aircraft research instrumentation system, including wing and flap surface pressure measurements and selected structural loads measurements; ground-based simulation to assess flying qualities; and finally, flight testing. This paper reviews the operational aspects associated with the flight experiment, which includes a description of modifications to the research airplane, the overall flight test procedures, and problems encountered. Selected research results are also presented to illustrate the accomplishments of the research effort.

Patient-based outcomes following surgical debridement and flap coverage of digital mucous cysts.

PubMed

Hojo, Junya; Omokawa, Shohei; Shigematsu, Koji; Onishi, Tadanobu; Murata, Keiichi; Tanaka, Yasuhito

2016-01-01

The purpose of this prospective cohort study was to evaluate patient-based outcomes and complications following excision of mucous cysts, joint debridement, and closure with one of three types of local flaps. From 2000-2011, 35 consecutive patients with 37 digital mucous cysts were treated surgically. The surgical procedure included excision of the cyst together with the attenuated skin, joint debridement on the affected side including capsulectomy, and removal of osteophytes. Depending on the size and location of the cyst, the skin defect was covered by a transposition flap (31 cysts), an advancement flap (two cysts), or a rotation flap (four cysts). At an average follow-up time of 4 years, 4 months, there was no wound infection, flap necrosis, or joint stiffness. Preoperative nail ridging resolved in seven of nine fingers, and no nail deformities developed after surgery. One cyst, treated with a transposition flap, recurred 10 months after surgery. The average satisfaction score for the affected finger significantly improved from 4.3 to 6.8, and the average pain score decreased from 4.7 to 2.3. This treatment protocol provides reliable results. Patients were satisfied with the reduction of associated pain and the postoperative appearance of the treated finger, and postoperative complications were minimal.

Vertical Profunda Artery Perforator Flap for Plantar Foot Wound Closure: A New Application.

PubMed

Alfonso, Allyson R; Mayo, James L; Sharma, Vishal K; Allen, Robert J; Chiu, Ernest S

2018-02-01

Plantar foot reconstruction requires special consideration of both form and function. There are several fasciocutaneous flap options, each with indications and reservations. This case presents a new application of the vertical profunda artery perforator flap for definitive closure of a neuropathic foot ulcer in a young woman with spina bifida. The postoperative course was uneventful, and the flap survived completely. The surgical and donor sites were without wound recurrence at 5-month follow-up. Understanding the variability of foot flap options is important because of unique cases such as the one presented where the wound was caused by specific and less commonly observed foot anatomy. The specific choice to use the vertical profunda artery perforator flap for this patient and her neuropathic wound type was made based on its excellent flexibility, durability, and donor site appeal. The vertical profunda artery perforator flap has adequate surface area and bulk and a favorable pedicle length and caliber, can be thinned, and leaves a donor scar in a less conspicuous area than other popular free flaps for lower-extremity reconstruction. For these reasons, it should be considered a first-line therapy for free flap coverage of selected foot wounds.

Production frequency effects in perception of phonological variation

NASA Astrophysics Data System (ADS)

Connine, Cynthia M.; Ranbom, Larissa J.

2004-05-01

Two experiments were conducted that investigated the relationship between phonological variant occurrence frequency (based on a corpus analysis of conversational speech) and auditory word recognition. The variant investigated was an alternation between the presence of [nt] and a nasal flap (e.g., center, cen'er). The corpus analysis showed that 80% of productions are nasal flaps, with wide variability across words (from 0% for ``enter'' to 100% for ``twenty''). In a production goodness rating experiment, listeners rated [nt] productions as better than their nasal flap counterparts. For individual items, a strong positive correlation was found between nasal flap frequency and goodness ratings: words typically produced with nasal flaps were rated as better productions. A lexical decision experiment showed that nasal flap variants were recognized more slowly and less accurately than [nt] versions. The rated quality of the nasal-flapped production was strongly correlated with the results of the lexical decision task: nasal-flapped words considered highly acceptable were recognized more quickly and accurately than words rated as poor nasal flap productions. The results demonstrate a strong relationship between experienced variant frequency and auditory word recognition and suggest that phonological variation is explicitly represented in the mental lexicon.

An Alternative Posterosuperior Auricular Fascia Flap for Ear Elevation During Microtia Reconstruction.

PubMed

Li, Yiyuan; Zhang, Ruhong; Zhang, Qun; Xu, Zhicheng; Xu, Feng; Li, Datao

2017-02-01

Advances in staged total auricular reconstruction have resulted in improved anterior auricular appearance; however, satisfactory postreconstruction esthetics of the retroauricular fold remain challenging. The postauricular appearance of the reconstructed ear depends largely upon optimizing the covering material. When used as the covering soft tissue for ear elevation, a flap containing primarily the upper portion of the retroauricular fascia has potential advantages over the conventional book cover-type retroauricular fascia flap. We developed a geometrically designed, posterosuperior auricular fascia flap to replace the conventional retroauricular fascia flap for ear elevation. During the second-stage operation, the posterosuperior auricular fascia flap is rotated downward and turned over to wrap around the inner strut and entire posterior auricular surface. Compared to the conventional book cover-type retroauricular fascia flap, the novel posterosuperior auricular fascia flap was easier to harvest and the operative time significantly decreased (110.3 vs. 121.5 min, p < 0.01). The modified flap produced a thin and natural contour of the postauricular surface, as well as reduced the incidence of postauricular hypertrophic scarring (from 24.7 to 13.2%, p = 0.03) and partial skin graft necrosis (from 43.4 to 31.2%, p = 0.01). The geometrically designed posterosuperior auricular fascia flap improves ear elevation. Compared to the conventional book cover-type retroauricular fascia flap, this covering tissue is easier to perform so the surgical time is decreased. It was highly vascularized, well defined, thinner, and yields reliable results. Thus, favorable postauricular surface results can be achieved during auricular reconstruction by using the modified fascia flap. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Inferiorly based buccinator myomucosal island flap in oral and pharyngeal reconstruction. Four techniques to increase its application

PubMed Central

Rahpeyma, Amin; khajehahmadi, Saeedeh

2015-01-01

Introduction Reconstruction of oral and pharyngeal defects after pathologic resections with the same tissue is an optimal and ideal target. Islanded variety of inferiorly pedicled facial artery musculomucosal flap, in which facial artery and vein are skeletonized (referred to as inferiorly based BUMIF), is suitable for reconstruction of medium-sized mucosal defects. Presentation of cases In this article, with four cases, modifications of this flap are demonstrated in reconstruction of large intraoral and oropharyngeal defects and coverage of alveolar ridge in the mandible. Discussion In some situations, there is a need for more mucosal paddle, longer vascular pedicle and more adaptation to the recipient bed. Conclusion Relocating Stensen’s duct increases the mucosal paddle with cranial extension of superior limit while differential incision of the mucosa and buccinator muscle in mandibular vestibule extend the lower limit of this flap. Bone suture is a good complementary technique when this flap is used for coverage of mandibular alveolar ridge. Inferiorly based BUMIF with added length is indicated for oropharyngeal and contralateral mouth floor reconstructions. PMID:26218177

A study about the split drag flaps deflections to directional motion of UiTM's blended wing body aircraft based on computational fluid dynamics simulation

NASA Astrophysics Data System (ADS)

Mohamad, Firdaus; Wisnoe, Wirachman; Nasir, Rizal E. M.; Kuntjoro, Wahyu

2012-06-01

This paper discusses on the split drag flaps to the yawing motion of BWB aircraft. This study used split drag flaps instead of vertical tail and rudder with the intention to generate yawing moment. These features are installed near the tips of the wing. Yawing moment is generated by the combination of side and drag forces which are produced upon the split drag flaps deflection. This study is carried out using Computational Fluid Dynamics (CFD) approach and applied to low subsonic speed (0.1 Mach number) with various sideslip angles (β) and total flaps deflections (δT). For this research, the split drag flaps deflections are varied up to ±30°. Data in terms of dimensionless coefficient such as drag coefficient (CD), side coefficient (CS) and yawing moment coefficient (Cn) were used to observe the effect of the split drag flaps. From the simulation results, these split drag flaps are proven to be effective from ±15° deflections or 30° total deflections.

Technical and Economic Analyses to Assess the Feasibility of Using Propellant - No. 2 Fuel Oil Slurries as Supplemental Fuels

DTIC Science & Technology

1991-09-01

proneilant contains predominantly nitrocellulose; double-base propellant is a solution of nit oglycerin plasticizer in nitocellulose; and triple-base...nitrocellulose- based propellants to promote long-term stability and prolong the safe storage life of these materials. The chemical compounds which...bases. Dibutylphthalate Plasticizer . Peptizes binders such as nitrocellulose (DBP) so that fibers form plastics such as propellant. Improves mechanical

Destruction of propellant magazine, November 1982

NASA Astrophysics Data System (ADS)

Tozer, N. H.

1984-08-01

Details on the destruction of a propellant magazine are given. The properties of single base propellants are discussed. Although single base propellants have been around for one hundred years, production of this type of propellant in Australia only commenced during World War 2 when appropriate plant and know how were provided under the Lend Lease Scheme. Most of the single base propellants made at Mulwala Explosives Factory have been of the IMR type i.e., single perforated tubular granules with their surface coated with DNT for use in small to medium calibre ammunition. Since production started at Mulwala Explosives Factory in 1944 some fourteen different versions of style of propellant have been manufactured. Four versions only were made up until 1957 and these were identified with an IMR type number matching the US propellants from which they were copied. New varieties introduced since 1957 have been identified with an AR aeries number commencing with AR2001 - the original Australian 7.62 mm rifle propellant.

Superfast high-resolution absolute 3D recovery of a stabilized flapping flight process.

PubMed

Li, Beiwen; Zhang, Song

2017-10-30

Scientific research of a stabilized flapping flight process (e.g. hovering) has been of great interest to a variety of fields including biology, aerodynamics, and bio-inspired robotics. Different from the current passive photogrammetry based methods, the digital fringe projection (DFP) technique has the capability of performing dense superfast (e.g. kHz) 3D topological reconstructions with the projection of defocused binary patterns, yet it is still a challenge to measure a flapping flight process with the presence of rapid flapping wings. This paper presents a novel absolute 3D reconstruction method for a stabilized flapping flight process. Essentially, the slow motion parts (e.g. body) and the fast-motion parts (e.g. wings) are segmented and separately reconstructed with phase shifting techniques and the Fourier transform, respectively. The topological relations between the wings and the body are utilized to ensure absolute 3D reconstruction. Experiments demonstrate the success of our computational framework by testing a flapping wing robot at different flapping speeds.

Advances in imaging technologies for planning breast reconstruction

PubMed Central

Mohan, Anita T.

2016-01-01

The role and choice of preoperative imaging for planning in breast reconstruction is still a disputed topic in the reconstructive community, with varying opinion on the necessity, the ideal imaging modality, costs and impact on patient outcomes. Since the advent of perforator flaps their use in microsurgical breast reconstruction has grown. Perforator based flaps afford lower donor morbidity by sparing the underlying muscle provide durable results, superior cosmesis to create a natural looking new breast, and are preferred in the context of radiation therapy. However these surgeries are complex; more technically challenging that implant based reconstruction, and leaves little room for error. The role of imaging in breast reconstruction can assist the surgeon in exploring or confirming flap choices based on donor site characteristics and presence of suitable perforators. Vascular anatomical studies in the lab have provided the surgeon a foundation of knowledge on location and vascular territories of individual perforators to improve our understanding for flap design and safe flap harvest. The creation of a presurgical map in patients can highlight any abnormal or individual anatomical variance to optimize flap design, intraoperative decision-making and execution of flap harvest with greater predictability and efficiency. This article highlights the role and techniques for preoperative planning using the newer technologies that have been adopted in reconstructive clinical practice: computed tomographic angiography (CTA), magnetic resonance angiography (MRA), laser-assisted indocyanine green fluorescence angiography (LA-ICGFA) and dynamic infrared thermography (DIRT). The primary focus of this paper is on the application of CTA and MRA imaging modalities. PMID:27047790

Aerodynamic comparison of a butterfly-like flapping wing-body model and a revolving-wing model

NASA Astrophysics Data System (ADS)

Suzuki, Kosuke; Yoshino, Masato

2017-06-01

The aerodynamic performance of flapping- and revolving-wing models is investigated by numerical simulations based on an immersed boundary-lattice Boltzmann method. As wing models, we use (i) a butterfly-like model with a body and flapping-rectangular wings and (ii) a revolving-wing model with the same wings as the flapping case. Firstly, we calculate aerodynamic performance factors such as the lift force, the power, and the power loading of the two models for Reynolds numbers in the range of 50-1000. For the flapping-wing model, the power loading is maximal for the maximum angle of attack of 90°, a flapping amplitude of roughly 45°, and a phase shift between the flapping angle and the angle of attack of roughly 90°. For the revolving-wing model, the power loading peaks for an angle of attack of roughly 45°. In addition, we examine the ground effect on the aerodynamic performance of the revolving-wing model. Secondly, we compare the aerodynamic performance of the flapping- and revolving-wing models at their respective maximal power loadings. It is found that the revolving-wing model is more efficient than the flapping-wing model both when the body of the latter is fixed and where it can move freely. Finally, we discuss the relative agilities of the flapping- and revolving-wing models.

Supraclavicular Artery Flap for Head and Neck Oncologic Reconstruction: An Emerging Alternative

PubMed Central

Shenoy, Ashok; Patil, Vijayraj S.; Prithvi, B. S.; Chavan, P.; Halkud, Rajshekar

2013-01-01

Aim. Head and Neck oncologic resections often leave complex defects which are challenging to reconstruct. The need of the hour is a versatile flap which has the advantages of both a regional flap (viz. reliable and easy to harvest) and a free flap (thin, pliable with good colour match). In this a study we assessed the usefulness of the supraclavicular artery flap in head and neck oncologic defects. Materials and Method. The flap was used as a pedicled fasciocutanous and was based on the transverse supraclavicular artery. We assessed this reconstructive option for complications as well as its and functional out comes. Results. Eleven cases underwent supraclavicular artery flap between 20011-2012 of which 5 were males and 6 females. Mean defect size was 5 cm × 6 cm. Nine donor sites were closed primarily and 1 required split skin grafting. We encountered one complete flap loss which was attributed to a band of constricting skin bridge over the vascular pedicle in a defect involving lateral third of midface. Two patient developed pharyngeocutaneous fistula (without flap loss) out of 3 patients who underwent augmentation pharyngoplasty post Near total laryngectomy. Conclusion. Supra clavicular artery flap is a thin versatile, reliable, easy to harvest, with good cosmetic and functional outcome at both ends (recipient and donor) for reconstructing head and neck oncologic defects. PMID:24490064

Anatomical and technical tips for use of the superficial inferior epigastric artery (SIEA) flap in breast reconstructive surgery.

PubMed

Dorafshar, Amir H; Januszyk, Michael; Song, David H

2010-08-01

Techniques for autologous breast reconstruction have evolved to minimize donor-site morbidity and reduce flap-specific complications. When available, the superficial inferior epigastric artery (SIEA) flap represents the optimal method to achieve the former. However, many microsurgeons have been reluctant to adopt this procedure due to technical challenges inherent to the surgery, as well as concerns with the intrinsic capacity of the superficial vessel system to adequately support this flap. This article sets forth a simple approach to the SIEA flap harvest and demonstrates that favorable results may be achieved even for small caliber vessels. A total of 46 patients underwent 53 SIEA breast reconstructions over a 6-year period using a modified approach for pedicle dissection and arterial inclusion criteria solely on the basis of presence of a palpable pulse. Average pedicle length harvested for all SIEA flaps was 6.07 cm; and mean arterial (0.96 mm) and venous (2.27 mm) diameters represent the lowest published values. Three flaps (5.7%) demonstrated fat necrosis or partial flap necrosis, with one (1.9%) complete flap loss. These results compare favorably with those of previous SIEA series employing diameter-based selection criteria, suggesting that the presence of a palpable arterial pulse may be sufficient to permit successful utilization of this flap. (c) Thieme Medical Publishers.

An Adjoint-Based Approach to Study a Flexible Flapping Wing in Pitching-Rolling Motion

NASA Astrophysics Data System (ADS)

Jia, Kun; Wei, Mingjun; Xu, Min; Li, Chengyu; Dong, Haibo

2017-11-01

Flapping-wing aerodynamics, with advantages in agility, efficiency, and hovering capability, has been the choice of many flyers in nature. However, the study of bio-inspired flapping-wing propulsion is often hindered by the problem's large control space with different wing kinematics and deformation. The adjoint-based approach reduces largely the computational cost to a feasible level by solving an inverse problem. Facing the complication from moving boundaries, non-cylindrical calculus provides an easy extension of traditional adjoint-based approach to handle the optimization involving moving boundaries. The improved adjoint method with non-cylindrical calculus for boundary treatment is first applied on a rigid pitching-rolling plate, then extended to a flexible one with active deformation to further increase its propulsion efficiency. The comparison of flow dynamics with the initial and optimal kinematics and deformation provides a unique opportunity to understand the flapping-wing mechanism. Supported by AFOSR and ARL.

Aerodynamic analysis of natural flapping flight using a lift model based on spanwise flow

NASA Astrophysics Data System (ADS)

Alford, Lionel D., Jr.

This study successfully described the mechanics of flapping hovering flight within the framework of conventional aerodynamics. Additionally, the theory proposed and supported by this research provides an entirely new way of looking at animal flapping flight. The mechanisms of biological flight are not well understood, and researchers have not been able to describe them using conventional aerodynamic forces. This study proposed that natural flapping flight can be broken down into a simplest model, that this model can then be used to develop a mathematical representation of flapping hovering flight, and finally, that the model can be successfully refined and compared to biological flapping data. This paper proposed a unique theory that the lift of a flapping animal is primarily the result of velocity across the cambered span of the wing. A force analysis was developed using centripetal acceleration to define an acceleration profile that would lead to a spanwise velocity profile. The force produced by the spanwise velocity profile was determined using a computational fluid dynamics analysis of flow on the simplified wing model. The overall forces on the model were found to produce more than twice the lift required for hovering flight. In addition, spanwise lift was shown to generate induced drag on the wing. Induced drag increased both the model wing's lift and drag. The model allowed the development of a mathematical representation that could be refined to account for insect hovering characteristics and that could predict expected physical attributes of the fluid flow. This computational representation resulted in a profile of lift and drag production that corresponds to known force profiles for insect flight. The model of flapping flight was shown to produce results similar to biological observation and experiment, and these results can potentially be applied to the study of other flapping animals. This work provides a foundation on which to base further exploration and hypotheses regarding flapping flight.

Distally based saphenous neurocutaneous perforator flap combined with vac therapy for soft tissue reconstruction and hardware salvage in the lower extremities.

PubMed

Wen, Gen; Wang, Chun-Yang; Chai, Yi-Min; Cheng, Liang; Chen, Ming; Yi-Min, L V

2013-11-01

The complex wound with the exposed hardware and infection is one of the common complications after the internal fixation of the tibia fracture. The salvage of hardware and reconstruction of soft tissue defect remain challenging. In this report, we presented our experience on the use of the distally based saphenous neurocutaneous perforator flap combined with vacuum-assisted closure (VAC) therapy for the coverage of the soft tissue defect and the exposed hardware in the lower extremity with fracture. Between January 2008 and July 2010, seven patients underwent the VAC therapy followed by transferring a reversed saphenous neurocutaneous perforator flap for reconstruction of the wound with exposed hardware around the distal tibia. The sizes of the flaps ranged from 6 × 3 cm to 15 × 6 cm. Six flaps survived completely. Partial necrosis occurred in one patient. There were no other complications of repair and donor sites. Bone healing was achieved in all patients. In conclusion, the reversed saphenous neurocutaneous perfortor flaps combined with the VAC therapy might be one of the options to cover the complex wound with exposed hardware in the lower extremities. © 2013 Wiley Periodicals, Inc.

Fundamental principles in periodontal plastic surgery and mucosal augmentation--a narrative review.

PubMed

Burkhardt, Rino; Lang, Niklaus P

2014-04-01

To provide a narrative review of the current literature elaborating on fundamental principles of periodontal plastic surgical procedures. Based on a presumptive outline of the narrative review, MESH terms have been used to search the relevant literature electronically in the PubMed and Cochrane Collaboration databases. If possible, systematic reviews were included. The review is divided into three phases associated with periodontal plastic surgery: a) pre-operative phase, b) surgical procedures and c) post-surgical care. The surgical procedures were discussed in the light of a) flap design and preparation, b) flap mobilization and c) flap adaptation and stabilization. Pre-operative paradigms include the optimal plaque control and smoking counselling. Fundamental principles in surgical procedures address basic knowledge in anatomy and vascularity, leading to novel appropriate flap designs with papilla preservation. Flap mobilization based on releasing incisions can be performed up to 5 mm. Flap adaptation and stabilization depend on appropriate wound bed characteristics, undisturbed blood clot formation, revascularization and wound stability through adequate suturing. Delicate tissue handling and tension free wound closure represent prerequisites for optimal healing outcomes. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Tracheostomy

PubMed Central

Dukes, Heather M.

1970-01-01

In this paper a comparison has been made between excision-type window tracheostomies and classical Björk flap and modified flap tracheostomies, based upon a review of all tracheostomies performed at Harare Hospital, Salisbury, over a 20-month period, together with bronchoscopic follow-up whenever possible. The modified flap type of tracheostomy is constructed by means of a broad-based flap dividing two tracheal rings and having rounded corners. It produces a good stoma through which tube changing can be performed with ease and safety. Any form of permanent defect in the trachea left by merely extubating a tracheostomy will almost always produce a narrowing at the level of the stoma, which is probably most severe if a flap-type of stoma has been made. Routine replacement of a modified flap will nearly always avoid this. A serious stricture was produced in three (3%) patients in the series. In two, this was at the level of the tube tip in patients who had been on prolonged artificial ventilation; one required resection. These strictures are probably due to movement of the tube tip during ventilator therapy, and it is suggested that some method of coupling the ventilator to the tube might be devised to avoid this. PMID:5489180

Design and creation of an experimental program of advanced training in reconstructive microsurgery.

PubMed

Lorenzo, Andrés R; Alvarez, Angel; Garcia-Barreiro, Juan; Centeno, Alberto; Lopez, Eduardo; Martelo, Francisco

2006-01-01

In this study, we design an experimental protocol for the purpose of enhancing performance in training in microsurgery. It is based on five free tissue transfer exercises in rat (epigastric cutaneous flap, saphenous fasciocutaneous flap, epigastric neurovascular flap, saphenous muscular flap, and hindlimb replantation), which simulate the principal clinical procedures of reconstructive microsurgery. The first part of the study consists of an anatomical review of the flaps of 5 rats and in the second part we have carried out the free transfer of flaps on 25 rats divided into 5 groups. To differentiate between them, we have created a mathematical function, referred to as difficulty in a microsurgical exercise, which has enabled us to establish a scale of progression for training, ranging form the easiest to the most difficult. As a conclusion, we believe that this protocol is a useful instrument as it allows for a more precise assessment of microsurgical capacity due to enhanced accuracy in the reproduction of global procedures and the fact that the quantification of progress in training is based on clinical monitoring after 7 days. (c) 2006 Wiley-Liss, Inc. Microsurgery, 2006.

Predicted Aerodynamic Characteristics of a NACA 0015 Airfoil Having a 25% Integral-Type Trailing Edge Flap

NASA Technical Reports Server (NTRS)

Hassan, Ahmed

1999-01-01

Using the two-dimensional ARC2D Navier-Stokes flow solver analyses were conducted to predict the sectional aerodynamic characteristics of the flapped NACA-0015 airfoil section. To facilitate the analyses and the generation of the computational grids, the airfoil with the deflected trailing edge flap was treated as a single element airfoil with no allowance for a gap between the flap's leading edge and the base of the forward portion of the airfoil. Generation of the O-type computational grids was accomplished using the HYGRID hyperbolic grid generation program. Results were obtained for a wide range of Mach numbers, angles of attack and flap deflections. The predicted sectional lift, drag and pitching moment values for the airfoil were then cast in tabular format (C81) to be used in lifting-line helicopter rotor aerodynamic performance calculations. Similar were also generated for the flap. Mathematical expressions providing the variation of the sectional lift and pitching moment coefficients for the airfoil and for the flap as a function of flap chord length and flap deflection angle were derived within the context of thin airfoil theory. The airfoil's sectional drag coefficient were derived using the ARC2D drag predictions for equivalent two dimensional flow conditions.

The complicated role of venous drainage on the survival of arterialized venous flaps

PubMed Central

Weng, Weidong; Zhang, Feng; Zhao, Bin; Wu, Zhipeng; Gao, Weiyang; Li, Zhijie; Yan, Hede

2017-01-01

The arterialized venous flap (AVF) has been gradually popularized in clinical settings; however, its survival is still inconsistent and the role of venous drainage remains elusive. In this study, we aimed to investigate the role of venous drainage on the flap survival of arterialized venous flaps. An arterialized venous flap was outlined symmetrically in the rabbit abdomen. The arterial perfusion flap with a unilateral vascular pedicle was taken as the control group and three other experimental groups (I, II and III) were designed based on the number of drainage veins (n = 1, 2 and 3 in the three groups, respectively). Compared with the control group, significant venous congestion was noted in all the experimental groups and the most severe one was seen in group I; while no statistical difference was observed between groups II and III. Similar results regarding blood perfusion state, epidermal metabolite levels and flap survival status were obtained among the three groups. These findings suggested that venous drainage is vital in the survival of the flap, but unlike in the arterial perfusion flaps, the problem of venous congestion can only be partially solved by increasing the number of draining veins. Further studies are warranted to gain insight into this complicated issue. PMID:28145882

Long-term outcome of using posterior-thigh fasciocutaneous flaps for the treatment of ischial pressure sores.

PubMed

Lin, Haodong; Hou, Chunlin; Chen, Aimin; Xu, Zhen

2010-08-01

Among the many difficult problems presented by patients with spinal cord injuries, management of ischial pressure ulcers remains challenging for reconstructive surgeons. This study describes the long-term outcome of using posterior-thigh fasciocutaneous flaps for the treatment of ischial pressure sores. Between January 1999 and June 2003, 12 patients with ischial sores were enrolled in this study. All the patients underwent early aggressive surgical debridement followed by surgical reconstruction with a laterally based posterior-thigh fasciocutaneous flap. The follow-up period ranged from 24 months to 97 months (mean, 62 months). All the flaps survived, and there were no partial flap losses. Primary-wound healing occurred in all the cases. In two patients, Grade II ischial pressure sores recurred 24 months and 27 months after the operation. There was no recurrence in the other 10 patients. The posterior-thigh fasciocutaneous pedicled flap was a good method for treating ischial bed sores. This flap could be used to treat recurrences observed after primary bed-sore treatment with other methods. The flap was easy to raise, and it did not cause any donor-site morbidity. The long-term outcome of using posterior-thigh fasciocutaneous flaps for the treatment of ischial pressure sores was generally good. (c) Thieme Medical Publishers.

[Vertical rectus abdominis myocutaneous flap for the closure of perineal wound after abdominoperineal resection of the rectum].

PubMed

Orhalmi, J; Vreský, B; Holéczy, P; Jackanin, S; Biath, P

2009-06-01

A major source of morbidity after abdominoperineal resection (APR) after neoadjuvant external beam pelvic radiation are perineal wound complications. Wound complications are common for 25-66% of patients overall. There are many of procedures provided to reconstruct the perineal defect after APR e.g. primary closure, secondary closure, superior gluteal artery flap and vertical rectus abdominus myocutaneous (VRAM) flap. Our purpose was to describe the effect of VRAM flap on reconstruction of perineal wound. VRAM flaps are ideally suited to bring nonirradiated tissue into defect associated with radical surgical extirpation procedures and irradiated fields. This flap, distally based in the deep inferior epigastric vessels, provides several distinct advantages. It is well perfused by the robust dominant pedicle and the deep inferior epigastric artery and vein. In addition, this flap provides adequate muscle bulk to obliterate pelvic dead space. The skin island can be used for resurfacing the perineal region, including the vaginal wall, and provides versatility for all patterns of resection. VRAM flap provides very good aesthetic and functional results, is technically relatively simple and radically decreases wound complications rate. The additional possibility is pull-through the flap transpelvically intraabdominally instead of pull-through via subcutaneous channel, especially with females.

Assessment of Cost Impacts of Using Non-Toxic Propulsion in Satellites

NASA Astrophysics Data System (ADS)

Schiebener, P. J.; Gies, O.; Stuhlberger, J.; Schmitz, H.-D.

2002-01-01

The growing costs of space missions, the need for increased mission performance, and concerns associated with environmental issues deeply influence propulsion system design and propellant selection criteria. A propellant's performance was defined in the past exclusively in terms of specific impulse and density, but now high-performance, non-toxic, non-sophisticated mono- propellant systems are key drivers, and are considered for development to replace the traditional hydrazine (N2H4) mono-propellant thrusters. The mono-propellants under consideration are propellant formulations, which should be environmentally friendly, should have a high density, equal or better performance and better thermal characteristics than hydrazine. These considerations raised interest specially in the candidates of Hydroxylammonium Nitrate (HAN)-based propellants, Ammoniumdinitramide (ADN)-based propellants, Tri-ethanol (TEAN)-based propellants, Hydrazinium Nitroformate (HNF)-based propellants, Hydrogen Peroxide (H2O2)-based propellants. A near-term objective in consideration of satellite related process optimisation is to significantly reduce on-ground operations costs and at the same time improve mission performance. A far-term objective is to obtain a system presenting a very high performance, illustrated by a high specific impulse. Moving to a "non-toxic" propulsion system seems to be a solution to these two goals. The sought after benefits for non-toxic spacecraft mono-propellant propulsion are under investigation taking into account the four main parameters which are mandatory for customer satisfaction while meeting the price constraints: - Reliability, availability, maintainability and safety, - Manufacturing, assembly, integration and test, - Launch preparation and support, - Ground support equipment. These benefits of non-toxic mono-propellants can be proven by various examples, like an expected reduction of development costs due the non-toxicity of propellants which might allow "easier" design, reducing some inhibits for ground safety, leading to a shorter development time, and consequently to reduced program costs. Operational costs could be reduced due to the use of non-toxic propellant. Their non-toxicity, in comparison to the traditional propellants, will avoid special safety procedures and also parallelisation of processes during all phases of AIT and launch preparations. The costs directly associated with propellant handling, transport and storage should be lower, also follow-on costs risk is minimised because of the elimination or significant reduction of toxic and carcinogenic characteristics of the propellants. The physical characteristic and properties of some of the propellants formulations mentioned, like a higher density than hydrazine, support the beneficial aspects: a global S/C weight reduction could be achieved due to smaller tanks.

Aerodynamic characteristics of the ventilated design for flapping wing micro air vehicle.

PubMed

Zhang, G Q; Yu, S C M

2014-01-01

Inspired by superior flight performance of natural flight masters like birds and insects and based on the ventilating flaps that can be opened and closed by the changing air pressure around the wing, a new flapping wing type has been proposed. It is known that the net lift force generated by a solid wing in a flapping cycle is nearly zero. However, for the case of the ventilated wing, results for the net lift force are positive which is due to the effect created by the "ventilation" in reducing negative lift force during the upstroke. The presence of moving flaps can serve as the variable in which, through careful control of the areas, a correlation with the decrease in negative lift can be generated. The corresponding aerodynamic characteristics have been investigated numerically by using different flapping frequencies and forward flight speeds.

Aerodynamic Characteristics of the Ventilated Design for Flapping Wing Micro Air Vehicle

PubMed Central

Zhang, G. Q.; Yu, S. C. M.

2014-01-01

Inspired by superior flight performance of natural flight masters like birds and insects and based on the ventilating flaps that can be opened and closed by the changing air pressure around the wing, a new flapping wing type has been proposed. It is known that the net lift force generated by a solid wing in a flapping cycle is nearly zero. However, for the case of the ventilated wing, results for the net lift force are positive which is due to the effect created by the “ventilation” in reducing negative lift force during the upstroke. The presence of moving flaps can serve as the variable in which, through careful control of the areas, a correlation with the decrease in negative lift can be generated. The corresponding aerodynamic characteristics have been investigated numerically by using different flapping frequencies and forward flight speeds. PMID:24683339

Notes on the technique of landing airplanes equipped with wing flaps

NASA Technical Reports Server (NTRS)

Gough, Melvin N

1936-01-01

The proper landing of airplanes equipped with flaps, although probably no more difficult than landing without them, requires a different technique. The effects of flaps on the aerodynamics characteristics of a wing are given and, with the aid of figures and diagrams, a detailed comparison of the glide and landing of an airplane with and without flaps is made. The dangers attending improper execution and the importance of such factors as air speed fuselage attitude, glide-path angle, and control manipulation, upon all of which a pilot bases his judgement, are emphasized. Of most importance in connection with the use of flaps are: the maintenance of a sufficient margin of speed above the stall; a decisive use of the controls at the proper time; more cautious use of power during the approach glide; and, above all, the willingness to accept the steep nose-down attitude necessary in the glide resulting from the use of flaps.

Hypopharyngeal reconstruction using a circular stapler.

PubMed

Schultz, P; Dupret-Bories, A; Ciftci, S; Fath, L

2018-02-01

Distal anastomosis by tubed free flap is one of the main technical difficulties encountered during hypopharyngeal reconstruction. Although high flap survival probability can be achieved by experienced surgical teams, two complications are commonly observed at the flap-oesophagus junction: fistula and stenosis. Use of a circular stapler reduced the frequency of these complications by ensuring a perfectly circular and resistant suture line. Salivary stent placement is therefore unnecessary, allowing earlier resumption of feeding. The stapling procedure is simple, but a few technical skills are required, as the stapler is not specifically designed for this purpose. We describe the indications, surgical procedure and global results based on our series. We consider the forearm flap to be the gold standard for this reconstruction, but thicker flaps, such as pectoralis major flap, can also be used, but with poorer results in terms of healing and swallowing performance. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Semi-Empirical Prediction of Aircraft Low-Speed Aerodynamic Characteristics

NASA Technical Reports Server (NTRS)

Olson, Erik D.

2015-01-01

This paper lays out a comprehensive methodology for computing a low-speed, high-lift polar, without requiring additional details about the aircraft design beyond what is typically available at the conceptual design stage. Introducing low-order, physics-based aerodynamic analyses allows the methodology to be more applicable to unconventional aircraft concepts than traditional, fully-empirical methods. The methodology uses empirical relationships for flap lift effectiveness, chord extension, drag-coefficient increment and maximum lift coefficient of various types of flap systems as a function of flap deflection, and combines these increments with the characteristics of the unflapped airfoils. Once the aerodynamic characteristics of the flapped sections are known, a vortex-lattice analysis calculates the three-dimensional lift, drag and moment coefficients of the whole aircraft configuration. This paper details the results of two validation cases: a supercritical airfoil model with several types of flaps; and a 12-foot, full-span aircraft model with slats and double-slotted flaps.

Ipsilateral pedicled TRAM flaps: the safer alternative?

PubMed

Clugston, P A; Gingrass, M K; Azurin, D; Fisher, J; Maxwell, G P

2000-01-01

Transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction has become a commonly performed procedure in the 1990s. The original description of the procedure was that of an ipsilaterally based pedicle procedure. Concerns about potential folding of the pedicle with possible compromise of the vascular supply led many surgeons to prefer the contralateral pedicle. Subsequently, there have been several large clinical series of pedicled TRAM flaps showing a relatively high complication rate related to flap vascularity problems. Partial flap necrosis rates in pedicled TRAM series range from 5 to 44 percent. These findings resulted in many centers favoring free TRAM flap breast reconstruction, despite an increase in resource use and negligible differences in complication rates. Ipsilateral pedicle TRAM flap breast reconstruction is not a commonly reported procedure and is reserved for cases for which scars preclude use of the contralateral pedicle. Simplicity and versatility of flap shaping, improved maintenance of the inframammary fold, and lack of disruption of the natural xiphoid hollow give ipsilateral TRAM flaps further advantages. This study reports on a series of 252 consecutive ipsilateral TRAM flap reconstructions in 190 patients. The majority of patients underwent muscle-sparing procedures with preservation of a medial and a lateral strip of rectus muscle. Immediate reconstruction was done in 104 of the 190 patients. Skin-sparing (69 patients) or skin-reduction procedures (21 patients) were used in 90 of the 104 patients (87 percent) undergoing immediate reconstruction. Complication rates were comparable to those of series reported for contralateral TRAM flaps, except that partial flap necrosis (2.0 percent) was less in this series. Risk factors were analyzed with regard to the most common complications seen in this study. Ipsilateral TRAM flap breast reconstruction is our preferred method, if available, because we believe that it has several advantages over the contralateral pedicled TRAM and this report suggests a lower partial flap necrosis rate than previously reported.

Binding of Single Walled Carbon Nanotube to WT and Mutant HIV-1 Proteases: Analysis of Flap Dynamics and Binding Mechanism

PubMed Central

Meher, Biswa Ranjan; Wang, Yixuan

2012-01-01

Most of the currently treated HIV-1 protease (HIV-PR) inhibitors have been prone to suffer from the mutations associated drug resistance. Therefore, it is necessary to search for potent alternatives against the drug resistance. In the current study we have tested the single-walled carbon nanotube (SWCNT) as an inhibitor in wild type (WT) as well as in three primary mutants (I50VPR, V82APR and I84VPR) of the HIV-1-PR through docking the SWCNT in the active site region, and then performed all-atom MD simulations for the complexes. The conformational dynamics of HIV-PR with a 20 ns trajectory reveals that the SWCNT can effectively bind to the HIV-1-PR active site and regulate the flap dynamics such as maintaining the flap-flap closed. To gain an insight into the binding affinity, we also performed the MM-PBSA based binding free energy calculations for the four HIV-PR/SWCNT complexes. It was observed that, although the binding between the SWCNT and the HIV-PR decreases due to the mutations, the SWCNTs bind to the HIV-PRs 3–5 folds stronger than the most potent HIV-1-PR inhibitor, TMC114. Remarkably, the significant interactions with binding energy higher than 1 kcal/mol focus on the flap and active regions, which favors closing flap-flap and deactivating the active residues of the HIV-PR. The flap dynamics and binding strength information for HIV-PR and SWCNTs can help design SWCNT-based HIV-1-PR inhibitors. PMID:23142620

Experimental study on axial pedicled composite flap prefabrication with high density porous polyethylene implants: medporocutaneous flap.

PubMed

Kocman, A Emre; Kose, Aydan A; Karabagli, Yakup; Baycu, Cengiz; Cetin, Cengiz

2008-01-01

Composite flaps including soft tissues with bone or cartilage are widely used in reconstruction of three-dimensional defects, but have some disadvantages. Flap prefabrication with alloplastic implants is an alternative procedure. Axial pattern vascularised high density porous polyethylene (HDPP) implants are capable of sustaining skin grafts. The purpose of this study was to examine the vascularisation pattern of the skin island in a composite flap prefabrication model prepared with vascularised HDPP implants. Forty male Wistar rats divided into four groups were used. A 9.5 x 6 x 2 mm HDPP block was centered on the dissected saphenous pedicle and anchored under the abdominal skin in the experimental group I (n=10). In experimental group II (n=10) saphenous artery and vein were put between the skin and the implant. Thus, the structures were laid as skin, HDPP block, pedicle in experimental group I and skin, pedicle, HDPP block in experimental group II. HDPP block-implanted and pedicle-implanted only groups served as control groups I and II, respectively. Eight weeks after prefabrication, skin islands 1.5 x 5 cm in size incorporated with implants were elevated based on saphenous vessels in the experimental groups and skin islands only based on the pedicle in control group II. Skin islands of the same dimensions were raised as grafts in control group I. Nylon sheets were put under the flaps and grafts to prevent vascularisation from the recipient bed. Flap viability was assessed by measuring the surface area on the 7th day. Total necrosis developed in composite grafts of control group I. Flap survival was higher in experimental group II and control group II (45% and 46.8%) than in group I (29.28%). Histologic studies demonstrated fibrovascular ingrowth into the HDPP implants, except in control group I, with significant inflammatory response and necrosis. Vascularisation of skin and implants from the pedicle was seen also microangiographically. In conclusion, a composite flap prefabrication model including vascularised HDPP implant, skin and vascular carrier was developed. This new flap was termed a 'medporocutaneous flap'.

Osteomyocutaneous fibular flap harvesting: Computer-assisted planning of perforator vessels using Computed Tomographic Angiography scan and cutting guide.

PubMed

Battaglia, Salvatore; Maiolo, Vincenzo; Savastio, Gabriella; Zompatori, Maurizio; Contedini, Federico; Antoniazzi, Elisa; Cipriani, Riccardo; Marchetti, Claudio; Tarsitano, Achille

2017-10-01

Mandibular reconstruction performed after virtual planning has become more common during recent years. The gold standard for extensive mandibular reconstruction is of course a fibular free flap. In designing an osteomyocutaneous fibula flap, poor planning, aberrant anatomy and/or inadequate perforator vessels are the most frequent causes of complications and may force the surgeon to modify the flap design, explore the contralateral leg or harvest an additional microvascular flap. The goal of our study was to pre-operatively evaluate the vascular anatomy of the fibula and localize the cutaneous perforator vessels, so to create the fibular cutting guide based on the position of the cutaneous perforator and safely harvest the reconstructive flap. Twenty consecutive patients who were candidates for mandibular reconstruction using a fibular microvascular free flap were enrolled in this study between January 2016 and August 2016. The patients were preoperatively assessed with a Computed Tomographic scan of head and neck and with a Computed Tomographic Angiography (CTA) scan of the lower limbs to evaluate the vascular anatomy of the fibula. Virtual planning was carried out for all patients. The fibular cutting guide was based on the position of the perforator cutaneous vessels, which were used to harvest the cutaneous part of the flap. Preoperative CT measurements were performed in order to identify the cutaneous perforators on the patients' skin. Intraoperative checking was performed to evaluate the accuracy of the perforators' position and the reproducibility of the virtual planning. In 5 patients out of 20 (25%), anatomical anomalies were discovered, without clinical evidence. The perforator vessels were localized in all patients. The average difference between the CTA and the intraoperative perforator localization was 1 mm (range 0-2 mm). Fibular cutting guide was positioned and fitted the anatomy of the patients in all treated patients. This allowed us to perform the planned segmentation of the fibula, obtaining the correct number of segments. In all cases, flap insetting was carried out and skin paddle was positioned as preoperatively planned. Neither donor site complications nor flap complications occurred. Preoperative evaluation of the legs using CTA, in patients who undergo an osteomyocutaneous fibular free flap for mandibular reconstruction, is a valuable approach to reduce altered-anatomy related complications and to improve the accuracy and outcomes of the reconstruction, especially in reconstructions of complex defects. In these cases, a soft tissue-based cutting guide can be planned based on the perforator vessels of the skin paddle, minimizing the harvesting risks of vascular lesions. Further studies and longer follow-ups are needed to evaluate the long-term outcomes and advantages of this procedure. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

A New Technique for Coronaplasty in Penile Reconstruction.

PubMed

Sommeling, Casper E; De Wolf, Edward J; Salim, Ali; Monstrey, Stan; Opsomer, Dries; Claes, Karel; D'Arpa, Salvatore

2018-06-01

The coronaplasty is an important step of the phalloplasty procedure as it creates a prominent coronal ridge and a constricted coronal sulcus, resulting in the transformation of a regular skin flap into a flap resembling a circumcised penis. The aim of this article is to describe our new coronaplasty technique that exploits opposing contracting forces of 2 different skin grafts to hold the shape of a thick, distally based skin flap, resulting in a natural looking neo-phallus. A distally based flap is raised at the junction of the middle and distal thirds of the neo-phallus. The dissection continues until adequate mobilization is obtained, so the flap can stand almost perpendicular to the axis of the shaft. 2 separate full-thickness skin grafts are harvested and placed: the first at the raw undersurface of the flap, the second at the flap's donor site. To make the sulcus deeper and to define the ridge, the lower part of the graft placed on the undersurface of the distal flap is sutured with tacking sutures. Depending on the type of flap used this procedure can be done during the phalloplasty procedure itself (axial flaps) or at least 1 week later (perforator flaps). The new technique that we developed shows a more distinct coronal sulcus and coronal ridge, long-lasting results, and a more aesthetically pleasing and natural-appearing glans penis. The harvested distal flap is progressively thicker and not folded, resulting in a more naturally looking ridge. The donor site is deeper than other techniques, creating a well-defined sulcus. By using 2 skin grafts the opposing force vectors increase the projection of the ridge and the deepness of the sulcus. This technique results in a more prominent glans penis and is an important step in creating an almost naturally looking neo-phallus. This procedure can be applied to all different kind of flaps used for phalloplasty, both in an immediate or delayed fashion. As grafts are used, partial or complete graft lost can appear. Furthermore, attention must be paid not to incise the distal flap too deep so vascularity to the distal part of the flap will not be impaired. A continuous search to optimize the aesthetic outcome of the phalloplasty procedure is necessary and with this new coronaplasty technique we hope to raise attention and take another step toward creating "the real thing." Sommeling CE, De Wolf EJ, Salim A, et al. A New Technique for Coronaplasty in Penile Reconstruction. J Sex Med 2018;15:920-923. Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Effect of drooped-nose flaps on the experimental force and moment characteristics of an oblique wing

NASA Technical Reports Server (NTRS)

Hopkins, E. J.; Lovette, G. H.

1976-01-01

Six-component experimental force and moment data are presented for a low aspect ratio, oblique wing equipped with drooped-nose flaps and mounted on top of a body of revolution. These flaps were investigated on the downstream wing panel with the nose drooped 5 deg, 10 deg, 20 deg, and 30 deg, and on both wing panels with the nose drooped 30 deg. It was to determine if such flaps would make the moment curves more linear by controlling the flow separation on the downstream wing panel at high lift coefficients. The wing was elliptical in planform and had an aspect ratio of 6.0 (based on the unswept wing span). The wing was tested at sweep angles of 45 deg and 50 deg throughout the Mach number range from 0.25 to 0.95. The drooped-nose flaps alone were not effective in making the moment curves more linear; however, a previous study showed that Kruger nose flaps improved the linearity of the moment curves when the Kruger flaps were used on only the downstream wing panel equipped with drooped-nose flaps deflected 5 deg.

Reconstruction Techniques of Choice for the Facial Cosmetic Units.

PubMed

Russo, F; Linares, M; Iglesias, M E; Martínez-Amo, J L; Cabo, F; Tercedor, J; Costa-Vieira, R; Toledo-Pastrana, T; Ródenas, J M; Leis, V

2017-10-01

A broad range of skin flaps can be used to repair facial surgical defects after the excision of a tumor. The aim of our study was to develop a practical guideline covering the most useful skin grafts for each of the distinct facial cosmetic units. This was a multicenter study in which 10 dermatologists with extensive experience in reconstructive surgery chose their preferred technique for each cosmetic unit. The choice of flaps was based on personal experience, taking into account factors such as suitability of the reconstruction technique for the specific defect, the final cosmetic result, surgical difficulty, and risk of complications. Each dermatologist proposed 2 flaps in order of preference for each cosmetic subunit. A score of 10 was given to the first flap and a score of 5 to the second. The total score obtained for each of the options proposed by the participating dermatologists was used to draw up a list of the 3 best grafts for each site. There was notable unanimity of criteria among most of the dermatologists for reconstructive techniques such as the glabellar flap for defects of the medial canthus of the eye, the bilateral advancement flag flap or H flap for the forehead, the rotary door flap for the auricle of the ear, the Mustarde flap for the infraorbital cheek, the O-Z rotation flap for the scalp, the Tenzel flap for the lower eyelid, and the island flap for the upper lip. The results of this study will be useful as a practical guide to choosing the best reconstruction technique for each of the facial cosmetic units. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

AdVEGF-All6A+ Preconditioning of Murine Ischemic Skin Flaps Is Comparable to Surgical Delay.

PubMed

Gersch, Robert P; Fourman, Mitchell S; Phillips, Brett T; Nasser, Ahmed; McClain, Steve A; Khan, Sami U; Dagum, Alexander B; Bui, Duc T

2015-08-01

Surgical flap delay is commonly used in preconditioning reconstructive flaps to prevent necrosis. However, staged procedures are not ideal. Pharmacologic up-regulation of angiogenic and arteriogenic factors before flap elevation poses a nonsurgical approach to improve flap survival. Male Sprague Dawley rats were divided into control (n = 16), surgical delay (Delay), AdNull, AdEgr-1, and AdVEGF (n ≥ 9/group) groups. Delay rats had a 9 cm × 3 cm cranial based pedicle skin flap incised 10 days prior to elevation. Adenoviral groups received 28 intradermal injections (10(9) pu/animal total) throughout the distal two thirds of the flap 1 week prior to elevation. At postoperative day (POD) 0 flaps were elevated and silicone sheeting was placed between flap and wound bed. Perfusion analysis in arbitrary perfusion units of the ischemic middle third of the flap using laser Doppler imaging was conducted preoperatively and on POD 0, 3, and 7. Clinical and histopathologic assessments of the skin flaps were performed on POD 7. AdVEGF (50.8 ± 10.9 APU) and AdEgr-1 (39.3 ± 10.6 APU) perfusion levels were significantly higher than controls (16.5 ± 4.2 APU) on POD 7. Delay models were equivalent to controls (25.9 ± 6.8 APU). AdVEGF and Delay animals showed significantly more viable surface area on POD 7 (14.4 ± 1.3 cm(2), P < 0.01 and 12.4 ± 1.2 cm(2), P < 0.05, respectively) compared with Controls (8.7 ± 0.7 cm(2)). AdVEGF preconditioning resulted in flap survival comparable to surgical delay. Adenoviral preconditioning maintained perfusion levels postoperatively while surgical delay did not.

AdVEGF-All6A+ Preconditioning of Murine Ischemic Skin Flaps Is Comparable to Surgical Delay

PubMed Central

Gersch, Robert P.; Fourman, Mitchell S.; Phillips, Brett T.; Nasser, Ahmed; McClain, Steve A.; Khan, Sami U.; Dagum, Alexander B.

2015-01-01

Background: Surgical flap delay is commonly used in preconditioning reconstructive flaps to prevent necrosis. However, staged procedures are not ideal. Pharmacologic up-regulation of angiogenic and arteriogenic factors before flap elevation poses a nonsurgical approach to improve flap survival. Methods: Male Sprague Dawley rats were divided into control (n = 16), surgical delay (Delay), AdNull, AdEgr-1, and AdVEGF (n ≥ 9/group) groups. Delay rats had a 9 cm × 3 cm cranial based pedicle skin flap incised 10 days prior to elevation. Adenoviral groups received 28 intradermal injections (109 pu/animal total) throughout the distal two thirds of the flap 1 week prior to elevation. At postoperative day (POD) 0 flaps were elevated and silicone sheeting was placed between flap and wound bed. Perfusion analysis in arbitrary perfusion units of the ischemic middle third of the flap using laser Doppler imaging was conducted preoperatively and on POD 0, 3, and 7. Clinical and histopathologic assessments of the skin flaps were performed on POD 7. Results: AdVEGF (50.8 ± 10.9 APU) and AdEgr-1 (39.3 ± 10.6 APU) perfusion levels were significantly higher than controls (16.5 ± 4.2 APU) on POD 7. Delay models were equivalent to controls (25.9 ± 6.8 APU). AdVEGF and Delay animals showed significantly more viable surface area on POD 7 (14.4 ± 1.3 cm2, P < 0.01 and 12.4 ± 1.2 cm2, P < 0.05, respectively) compared with Controls (8.7 ± 0.7 cm2). Conclusions: AdVEGF preconditioning resulted in flap survival comparable to surgical delay. Adenoviral preconditioning maintained perfusion levels postoperatively while surgical delay did not. PMID:26495207

Reconstruction of large unilateral hemi-facial scar contractures with supercharged expanded forehead flaps based on the anterofrontal superficial temporal vessels.

PubMed

Gan, Cheng; Fan, Jincai; Liu, Liqiang; Tian, Jia; Jiao, Hu; Chen, Wenlin; Fu, Siqi; Feng, Suyun

2013-11-01

The expanded forehead flap, using temporal pedicles, has been employed extensively in facial reconstruction. To overcome the disadvantages of the traditional dual temporal pedicles, such as the limited transfer range and the short length of the flap, the distal supercharging technique can be applied to lengthen the flap and extend the transfer range, especially in the cases with a past temporal burn injury. This article aims to present an application of the distal supercharged expanded forehead flap procedure for hemi-facial reconstruction and discuss the haemodynamics of the expanded forehead flap. The tissue expander implantation and the following forehead tissue expansion were performed regularly. When the forehead skin expansion was completed, an expanded forehead flap was created and transferred to the damaged facial area with one distal temporal vessel pedicle that was anastomosed with facial vessels in a supercharged way. All patients were analysed retrospectively. From September 2009 to September 2011, eight male patients and one female patient were treated using this method. Their flaps size ranged from 20 cm × 8 cm to 30 cm × 11 cm and no flap loss occurred. Patients came in for follow-ups 9-16 months after the procedures. All the patients were satisfied with the results. The supercharging expanded forehead flap procedure can provide reliable flap vascularity due to its elastic transferring abilities. By using a distal supercharging technique, we can lengthen and widen the flap to tailor it to the defect, while also minimising the donor defect in the patients with a past temporal injury. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Combustion characteristics of SMX and SMX based propellants

NASA Astrophysics Data System (ADS)

Reese, David A.

This work investigates the combustion of the new solid nitrate ester 2,3-hydroxymethyl-2,3-dinitro-1,4-butanediol tetranitrate (SMX, C6H 8N6O16). SMX was synthesized for the first time in 2008. It has a melting point of 85 °C and oxygen balance of 0% to CO 2, allowing it to be used as an energetic additive or oxidizer in solid propellants. In addition to its neat combustion characteristics, this work also explores the use of SMX as a potential replacement for nitroglycerin (NG) in double base gun propellants and as a replacement for ammonium perchlorate in composite rocket propellants. The physical properties, sensitivity characteristics, and combustion behaviors of neat SMX were investigated. Its combustion is stable at pressures of up to at least 27.5 MPa (n = 0.81). The observed flame structure is nearly identical to that of other double base propellant ingredients, with a primary flame attached at the surface, a thick isothermal dark zone, and a luminous secondary flame wherein final recombination reactions occur. As a result, the burning rate and primary flame structure can be modeled using existing one-dimensional steady state techniques. A zero gas-phase activation energy approximation results in a good fit between modeled and observed behavior. Additionally, SMX was considered as a replacement for nitroglycerin in a double base propellant. Thermochemical calculations indicate improved performance when compared with the common double base propellant JA2 at SMX loadings above 40 wt-%. Also, since SMX is a room temperature solid, migration may be avoided. Like other nitrate esters, SMX is susceptible to decomposition over long-term storage due to the presence of excess acid in the crystals; the addition of stabilizers (e.g., derivatives of urea) during synthesis should be sufficient to prevent this. the addition of Both unplasticized and plasticized propellants were formulated. Thermal analysis of unplasticized propellant showed a distinct melt-recrystallization curve, which indicates that a solid phase solution is being formed between SMX and NC, and that SMX would not act as plasticizer. Analysis of propellant prepared with diethyleneglycol dinitrate (DEGDN) plasticizer indicates that the SMX is likely dissolved in the DEGDN. The plasticized material also showed similar hardness and modulus to JA2. However, both plasticized and unplasticized propellants exhibited deconsolidated burning at elevated pressures due to the high modulus of the propellant. Increased amounts of plasticizer or improved processing of the nitrocellulose should be investigated to remedy this issue. Safety characterization showed that sensitivity of the plasticized propellant is similar to JA2. In short, replacing NG with SMX results in a new family of propellants with acceptable safety characteristics and which may also offer improved theoretical performance. Finally, composite propellants based on SMX were theoretically and experimentally examined and compared to formulations based on ammonium perchlorate (AP). Thermochemical equilibrium calculations show that aluminized SMX-based formulations can achieve theoretical sea level specific impulse values upwards of 260 s-- slightly lower than an AP-based composite. Both ignition sensitivity (tested via drop weight impact, electro-static discharge, and BAM friction) and physical properties (hardness and thermal properties) are comparable to those of the AP-based formulations. However, the SMX-based formulation could be detonated using a high explosive donor charge in contact with the propellant, as do other low smoke propellants. Differential scanning calorimetry of the SMX-based propellant indicated an exotherm onset of 140 °C, which corresponds to the known decomposition temperature of SMX. The propellant has a high burning rate of 1.57 cm/s at 6.89 MPa, with a pressure exponent of 0.85. This high pressure sensitivity might be addressed using various energetic and/or stabilizing additives. With high density and performance, smokeless combustion products, and stable combustion, SMX appears to be a viable replacement for existing energetic ingredients in a wide variety of propellant, explosive, and pyrotechnic applications.

Performance analysis of mini-propellers based on FlightGear

NASA Astrophysics Data System (ADS)

Vogeltanz, Tomáš

2016-06-01

This paper presents a performance analysis of three mini-propellers based on the FlightGear flight simulator. Although a basic propeller analysis has to be performed before the use of FlightGear, for a complex and more practical performance analysis, it is advantageous to use a propeller model in cooperation with a particular aircraft model. This approach may determine whether the propeller has sufficient quality in respect of aircraft requirements. In the first section, the software used for the analysis is illustrated. Then, the parameters of the analyzed mini-propellers and the tested UAV are described. Finally, the main section shows and discusses the results of the performance analysis of the mini-propellers.

The revascularization of pedicle skin flaps in pigs: a functional and morphologic study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, C.M.

1982-10-01

Functional and morphologic changes occurring during the revascularization of pedicle flaps have been investigated in the skin of pigs. The skin flaps, 16 cm long by 4 cm wide, were based on a row of segmental vessels arising from the internal mammary artery. Comparative measurements were made in flapped and normal skin. The inherent blood supply in the pedicle of the flap was unable to maintain the whole of the flap in a viable state. Flap viability was ascertained at surgery by the use of the intravital dye Disulphine blue. Injections of the dye after surgery gave a less accuratemore » prediction of viability than when dye was injected prior to surgery. Revascularization between the flap and surrounding skin was evident 3 to 4 days postoperatively at the distal, most hypoxic part of the viable flap. The whole flap had a collateral vascular supply 7 to 10 days after surgery. Isotope clearance studies showed that the greatest functional changes occurred in the distal third of the viable flap, where, after initially slowing, the clearance rate became faster than in normal skin (day 5). Potassium extraction studies indicated similar changes. However, an increase in the red-cell volume on day 1 suggested that vascular shunting was occurring. The results of the morphologic studies indicated a correlation between the number of blood vessels per unit area, the thickness of the dermis, and the recorded functional changes. Seven days after surgery, when isotope clearance rates were very rapid, there was a significant increase in the vascular density and dermal thickness.« less

View from west sharp perspective, foundry/propeller shop. Naval Base ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View from west sharp perspective, foundry/propeller shop. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Foundry-Propeller Shop, North of Porter Avenue, west of Third Street West, Philadelphia, Philadelphia County, PA

A New Approach for the Correction of Prominent Ear Deformity: The Distally Based Perichondrio-Adipo-Dermal Flap Technique.

PubMed

Cihandide, Ercan; Kayiran, Oguz; Aydin, Elif Eren; Uzunismail, Adnan

2016-06-01

Otoplasty techniques are generally divided into 2 categories as cartilage-cutting and cartilage-sparing. The cartilage-cutting techniques have been criticized because of their high risk of hematoma, skin necrosis, and ear deformity. As a result, suture-based cartilage-sparing methods like Mustardé and Furnas-type suture techniques have become increasingly popular. However, with these techniques postauricular suture extrusion may be seen and recurrence rates of up to 25% have been reported. In this study, cartilage-sparing otoplasty is redefined by introduction of the distally based perichondrio-adipo-dermal flap which is elevated from the postauricular region. Thirty-seven ears (17 bilateral and 3 unilateral) in 20 patients (14 females and 6 males) have been operated with the defined technique by the same surgeon. The distally based perichondrio-adipo-dermal flap is advanced posteriorly to correct the deformity, also acting as a strong postauricular support to prevent recurrence. In addition to the resultant natural-looking antihelical fold, the posterior advancement of the flap corrects both the otherwise wide conchoscaphal and conchomastoid angles. The operative technique is explained in detail with results and the literature is reviewed. There were no hematomas. After an average follow-up of 8.3 months (2-16 months), recurrence was seen in only 1 patient who requested no further surgery. No patients developed suture extrusion or granuloma. The authors introduce a simple and safe procedure to correct prominent ears with benefits including a resultant natural-looking antihelical fold and less tissue trauma. The distally based perichondrio-adipo-dermal flap seems to prevent suture extrusion and may also help to reduce recurrence rates. By forming neochondrogenesis which is stimulated by elevation of the perichondrium, this flap gives the promise of longer durability of the newly formed antihelical fold.

Extended lateral thoracic fasciocutaneous biosynthetic flap for reconstruction of full-thickness partial external ear defects: an experimental study.

PubMed

Kuvat, Samet Vasfi; Taşkın, Ümit; Yücebaş, Kadir; Tansuker, Hasan Deniz; Oktay, Mehmet Faruk; Kozanoğlu, Erol; Aydın, Salih

2017-01-01

External ear reconstruction is a controversial topic in reconstructive plastic surgery. Here, we prepared a pedicled biosynthetic flap for full-thickness, partial ear defects in rabbits. We operated on six adult female New Zealand rabbits weighing 3-4 kg. The dimensions of the lateral thoracic fasciocutaneous flap were 7 × 6 cm. The flap was elevated based on one of the bilaterally located internal thoracic arteries, which were dissected proximally. The pedicled flap was folded in two, and polypropylene mesh was sandwiched in the middle. The flap was adapted to a defect of 3.5 × 3 cm in diameter. In fact, the defect was created before elevation of the flap. Rabbits were followed up for 4 weeks, at the end of which they were killed and their ears were evaluated histopathologically. The survival rate of the rabbits was 100 %. All pedicled biosynthetic flaps were viable, but one showed partial (20 %) necrosis (1/6) and one was partially detached (1/6). Macroscopic (color, thickness, texture) and histological (polymorphonuclear leukocyte invasion in the skin, subcutaneous tissue, and at the junction between the polypropylene mesh and the flap) features of the flap were compared to the ipsilateral ear. A new technique was developed for partial external ear reconstruction with sufficient inner skeletal support and outer skin lining. Level of evidence Level NA.

The Extended Nasoseptal Flap for Skull Base Reconstruction of the Clival Region: An Anatomical and Radiological Study

PubMed Central

Peris-Celda, Maria; Pinheiro-Neto, Carlos Diogenes; Funaki, Takeshi; Fernandez-Miranda, Juan C.; Gardner, Paul; Snyderman, Carl; Rhoton, Albert L.

2013-01-01

Objective Reconstruction of large clival defects after an endoscopic endonasal procedure is challenging. The objective is to analyze the morphology, indications, and limitations of the extended nasoseptal flap, which adds the nasal floor and inferior meatus mucosa, compared with the standard nasoseptal flap, for clival reconstruction. Design Twenty-seven sides of formalin-fixed anatomical specimens and 13 computed tomography (CT) scans were used. Under 0-degree endoscopic visualization, a standard flap on one side and an extended flap on the other side were performed, as well as exposure of the sella, cavernous sinus, and clival dura mater. Coverage of both flaps was assessed, and they were incised and extracted for measurements. Results The extended flap has two parts: septal and inferior meatal. The extended flaps are 20 mm longer and add 774 mm2 of mucosal area. They cover a clival defect from tuberculum to foramen magnum in 66.6% cases and from below the sella in 91.6%. They cover both parasellar and paraclival segments of the internal carotid arteries. The lateral inferior limits are the medial aspect of the hypoglossal canals and Eustachian tubes. CT scans can predict the need or limitation of an extended nasoseptal flap. Conclusions The nasal floor and inferior meatus mucosa adds a significant area for reconstruction of the clivus. A defect laterally beyond the hypoglossal canals is not likely covered with this variation of the flap. Preoperative CT scans are useful to guide the reconstruction techniques. PMID:24436940

An experimental study of the unsteady vortex structures in the wake of a root-fixed flapping wing

NASA Astrophysics Data System (ADS)

Hu, Hui; Clemons, Lucas; Igarashi, Hirofumi

2011-08-01

An experimental study was conducted to characterize the evolution of the unsteady vortex structures in the wake of a root-fixed flapping wing with the wing size, stroke amplitude, and flapping frequency within the range of insect characteristics for the development of novel insect-sized nano-air-vehicles (NAVs). The experiments were conducted in a low-speed wing tunnel with a miniaturized piezoelectric wing (i.e., chord length, C = 12.7 mm) flapping at a frequency of 60 Hz (i.e., f = 60 Hz). The non-dimensional parameters of the flapping wing are chord Reynolds number of Re = 1,200, reduced frequency of k = 3.5, and non-dimensional flapping amplitude at wingtip h = A/C = 1.35. The corresponding Strouhal number (Str) is 0.33 , which is well within the optimal range of 0.2 < Str < 0.4 used by flying insects and birds and swimming fishes for locomotion. A digital particle image velocimetry (PIV) system was used to achieve phased-locked and time-averaged flow field measurements to quantify the transient behavior of the wake vortices in relation to the positions of the flapping wing during the upstroke and down stroke flapping cycles. The characteristics of the wake vortex structures in the chordwise cross planes at different wingspan locations were compared quantitatively to elucidate underlying physics for a better understanding of the unsteady aerodynamics of flapping flight and to explore/optimize design paradigms for the development of novel insect-sized, flapping-wing-based NAVs.

A flap based on the plantar digital artery arch branch to improve appearance of reconstructed fingers: Anatomical and clinical application.

PubMed

Tang, Lin-Feng; Ju, Ji-Hui; Liu, Yue-Fei; Lan, Bo; Hou, Rui-Xing

2018-02-01

To investigate blood supply features of the flap based on the plantar digital artery arch and arch branch artery, and the treatment of outcomes of reconstructed fingers by the plantar digital artery arch branch island flap. Eight fresh foot specimens were employed with red emulsion infusion and microdissection. The vascular organization was observed in the second toe, such as initiation site, the course, and the number of the plantar digital artery arch branch. There were 15 fingers of 13 patients (8 males and 5 females) with finger defects accompanied by toe transfer, using the plantar digital artery arch branch flap inserted in the neck of the second toe to correct the appearance defect caused by a narrow "neck" and a bulbous tip. The intact plantar digital arches were identified in all specimens. The plantar digital artery arch had 5 branches. The range of external diameter of the arch branch was 0.4-0.6 mm. All the plantar digital artery arch branch island flaps and the reconstructed fingers survived. These cases were conducted with a follow-up period for 3-18 months (average, 9 months). All the plantar digital artery arch branch island flaps and reconstructed fingers demonstrated a satisfactory appearance and favorable sense function. The reconstructed finger-tip characteristic was good, with no obvious scar hyperplasia. The range of flexion and extension of reconstructed fingers was favorable as well. The plantar digital artery arch and arch branch artery possess regular vasa vasorum and abundant vascularity. A flap based on the plantar digital artery arch branch is an ideal selection for plastic surgery of reconstructed fingers. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Design charts for predicting downwash angles and wake characteristics behind plain and flapped wings

NASA Technical Reports Server (NTRS)

Silverstein, Abe; Katzoff, S

1939-01-01

Equations and design charts are given for predicting the downwash angles and the wake characteristics for power-off conditions behind plain and flapped wings of the types used in modern design practice. The downwash charts cover the cases of elliptical wings and wings of taper ratios 1, 2, 3, and 5, with aspect ratios of 6, 9, and 12, having flaps covering 0, 40, 70, and 100 percent of the span. Curves of the span load distributions for all these cases are included. Data on the lift and the drag of flapped airfoil sections and curves for finding the contribution of the flap to the total wing lift for different types of flap and for the entire range of flap spans are also included. The wake width and the distribution of dynamic pressure across the wake are given in terms of the profile-drag coefficient and the distance behind the wing. A method of estimating the wake position is also given. The equations and charts are based on theory that has been shown in a previous report to be in agreement with experiment.

Validation of a pair of computer codes for estimation and optimization of subsonic aerodynamic performance of simple hinged-flap systems for thin swept wings

NASA Technical Reports Server (NTRS)

Carlson, Harry W.; Darden, Christine M.

1988-01-01

Extensive correlations of computer code results with experimental data are employed to illustrate the use of linearized theory attached flow methods for the estimation and optimization of the aerodynamic performance of simple hinged flap systems. Use of attached flow methods is based on the premise that high levels of aerodynamic efficiency require a flow that is as nearly attached as circumstances permit. A variety of swept wing configurations are considered ranging from fighters to supersonic transports, all with leading- and trailing-edge flaps for enhancement of subsonic aerodynamic efficiency. The results indicate that linearized theory attached flow computer code methods provide a rational basis for the estimation and optimization of flap system aerodynamic performance at subsonic speeds. The analysis also indicates that vortex flap design is not an opposing approach but is closely related to attached flow design concepts. The successful vortex flap design actually suppresses the formation of detached vortices to produce a small vortex which is restricted almost entirely to the leading edge flap itself.

Wind-tunnel tests on model wing with Fowler flap and specially developed leading-edge slot

NASA Technical Reports Server (NTRS)

Weick, Fred E; Platt, Robert C

1933-01-01

An investigation was made in the NACA 7 by 10 foot wind tunnel to find the increase in maximum lift coefficient which could be obtained by providing a model wing with both a Fowler trailing-edge extension flap and a Handley Page type leading-edge slot. A conventional Handley page slot proportioned to operate on the plain wing without a flap gave but a slight increase with the flap; so a special form of slot was developed to work more effectively with the flap. With the best combined arrangement the maximum lift coefficient based on the original area was increased from 3.17, for the Fowler wing, to 3.62. The minimum drag coefficient with both devices retracted was increased in approximately the same proportion. Tests were also made with the special-type slot on the plain wing without the flap. The special slot, used either with or without the Fowler flap, gave definitely higher values of the maximum lift coefficient than the slots of conventional form, with an increase of the same order in the minimum drag coefficient.

Energetic Extremes in Aquatic Locomotion by Coral Reef Fishes

PubMed Central

Fulton, Christopher J.; Johansen, Jacob L.; Steffensen, John F.

2013-01-01

Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s−1) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed. PMID:23326566

The transverse musculo-cutaneous gracilis flap for breast reconstruction: How to avoid complications.

PubMed

Bodin, Frédéric; Dissaux, Caroline; Dupret-Bories, Agnes; Schohn, Thomas; Fiquet, Caroline; Bruant-Rodier, Catherine

2016-01-01

The transverse musculocutaneous gracilis (TMG) flap has become a common solution for breast reconstruction. However, the safe skin paddle limits are not yet understood. In this study, we attempted to address this issue based on our experiences with inferior and posterior skin paddle extension. Forty-four breast reconstructions with TMG flaps performed between November 2010 and January 2014 were analyzed retrospectively. For the first 20 cases, the flap skin paddle was extended 3 cm posteriorly to the middle thigh (group 1). For the next 20 flaps (group 2), the posterior tip was limited to this line, whereas more fat was recruited inferiorly. In the four cases of group 3, the skin flap was extended posteriorly with a second vascular pedicle from the profunda artery perforator (PAP) flap. The weights and the dimensions of the flaps, operating durations, and postoperative complications of the entire series were analyzed. Groups 1 and 2 were statistically compared. Flap complications were statistically more frequent in group 1 compared with group 2 (45 vs. 0%, P = 0.0012); 40% posterior flap tip necrosis was observed in group 1. Conversely, donor site complications were statistically more frequent in group 2 than in group 1 (40 vs. 5%, P = 0.019) with 35% inner thigh dehiscence. In the TMG with extended PAP flap group, the operating duration was 77 min longer compared with the rest of the series with no donor site complications. In one case, limited necrosis occurred at the anterior skin tip. Harvesting the posterior portion of the TMG up to the middle of the posterior thigh may lead to partial flap necrosis. Extending subcutaneous fat removal under the inferior skin incision may increase the risk of donor site complications. Adding a second vascular pedicle from the PAP flap may improve posterior TMG tip perfusion at the expense of a longer operation. © 2015 Wiley Periodicals, Inc.

Thrust generation by a heaving flexible foil: Resonance, nonlinearities, and optimality

NASA Astrophysics Data System (ADS)

Paraz, Florine; Schouveiler, Lionel; Eloy, Christophe

2016-01-01

Flexibility of marine animal fins has been thought to enhance swimming performance. However, despite numerous experimental and numerical studies on flapping flexible foils, there is still no clear understanding of the effect of flexibility and flapping amplitude on thrust generation and swimming efficiency. Here, to address this question, we combine experiments on a model system and a weakly nonlinear analysis. Experiments consist in immersing a flexible rectangular plate in a uniform flow and forcing this plate into a heaving motion at its leading edge. A complementary theoretical model is developed assuming a two-dimensional inviscid problem. In this model, nonlinear effects are taken into account by considering a transverse resistive drag. Under these hypotheses, a modal decomposition of the system motion allows us to predict the plate response amplitude and the generated thrust, as a function of the forcing amplitude and frequency. We show that this model can correctly predict the experimental data on plate kinematic response and thrust generation, as well as other data found in the literature. We also discuss the question of efficiency in the context of bio-inspired propulsion. Using the proposed model, we show that the optimal propeller for a given thrust and a given swimming speed is achieved when the actuating frequency is tuned to a resonance of the system, and when the optimal forcing amplitude scales as the square root of the required thrust.

Synthetic, structural mimetics of the β-hairpin flap of HIV-1 protease inhibit enzyme function.

PubMed

Chauhan, Jay; Chen, Shen-En; Fenstermacher, Katherine J; Naser-Tavakolian, Aurash; Reingewertz, Tali; Salmo, Rosene; Lee, Christian; Williams, Emori; Raje, Mithun; Sundberg, Eric; DeStefano, Jeffrey J; Freire, Ernesto; Fletcher, Steven

2015-11-01

Small-molecule mimetics of the β-hairpin flap of HIV-1 protease (HIV-1 PR) were designed based on a 1,4-benzodiazepine scaffold as a strategy to interfere with the flap-flap protein-protein interaction, which functions as a gated mechanism to control access to the active site. Michaelis-Menten kinetics suggested our small-molecules are competitive inhibitors, which indicates the mode of inhibition is through binding the active site or sterically blocking access to the active site and preventing flap closure, as designed. More generally, a new bioactive scaffold for HIV-1PR inhibition has been discovered, with the most potent compound inhibiting the protease with a modest K(i) of 11 μM. Copyright © 2015 Elsevier Ltd. All rights reserved.

[APPLICATION OF WRIST CREASE ISLAND FLAP BASED ON THE SUPERFICIAL PALMAR BRANCH OF THE RADIAL ARTERY FOR THUMB RECONSTRUCTION].

PubMed

Zheng Dawei; Li, Zhangcan; Xu, Li; Zhang, Xuyang; Shi, Rongjian; Sun, Feng; Shou, Kuishui

2015-04-01

To investigate the effectiveness of the island flaps based on the superficial palmar branch of the radial artery (SPBRA) to repair the thumb wound. Between February 2012 and November 2013, 8 cases of thumb defects and bilateral artery defect were treated. There were 5 males and 3 females with an average age of 30.5 years (range, 19-51 years). The injury was caused by crush (4 cases), avulsion (3 cases), and twist (1 case). The injury located at the metacarpophalangeal joints in 3 cases, at the proximal palmar side in 2 cases, and at the interphalangeal joints in 3 cases. The defect size ranged from 3.5 cm x 1.5 cm to 6.5 cm x 2.0 cm. The digital artery defect was 2.5-8.5 cm (mean, 5.3 cm). The disease duration was 2.0-4.5 hours (mean, 3.2 hours). The reversed island flaps based on the SPBRA were designed, which size was 4.0 cm x 2.0 cm to 7.5 cm x 3.0 cm. The donor sites were closed directly. The operation was successfully completed in 7 patients except 1 patient having vascular variation. All flaps survived completely. Wound and incision at the donor site healed by first intention. All patients were followed up 6-18 months (mean, 13 months). The flaps had similar color and texture to adjacent skin. Linear scar was seen at the donor site in 1 patient, with no functional limitation. According to the functional assessment criteria of upper limb by the Hand Surgery Branch of Chinese Medical Association, the results were excellent in 6 cases, good in 1 case, and fair in 1 case, with an excellent and good rate of 87.5%. The reversed island flap based on the SPBRA is an ideal flap for the thumb reconstruction because the advantages of reliable blood supply, easy dissection, less injury at donor site, and good repair results.

Computational Design of a Krueger Flap Targeting Conventional Slat Aerodynamics

NASA Technical Reports Server (NTRS)

Akaydin, H. Dogus; Housman, Jeffrey A.; Kiris, Cetin C.; Bahr, Christopher J.; Hutcheson, Florence V.

2016-01-01

In this study, we demonstrate the design of a Krueger flap as a substitute for a conventional slat in a high-lift system. This notional design, with the objective of matching equivalent-mission performance on aircraft approach, was required for a comparative aeroacoustic study with computational and experimental components. We generated a family of high-lift systems with Krueger flaps based on a set of design parameters. Then, we evaluated the high-lift systems using steady 2D RANS simulations to find a good match for the conventional slat, based on total lift coefficients in free-air. Finally, we evaluated the mean aerodynamics of the high-lift systems with Krueger flap and conventional slat as they were installed in an open-jet wind tunnel flow. The surface pressures predicted with the simulations agreed well with experimental results.

Rational function representation of flap noise spectra including correction for reflection effects. [acoustic properties of engine exhaust jets deflected for externally blown flaps

NASA Technical Reports Server (NTRS)

Miles, J. H.

1974-01-01

A rational function is presented for the acoustic spectra generated by deflection of engine exhaust jets for under-the-wing and over-the-wing versions of externally blown flaps. The functional representation is intended to provide a means for compact storage of data and for data analysis. The expressions are based on Fourier transform functions for the Strouhal normalized pressure spectral density, and on a correction for reflection effects based on the N-independent-source model of P. Thomas extended by use of a reflected ray transfer function. Curve fit comparisons are presented for blown flap data taken from turbofan engine tests and from large scale cold-flow model tests. Application of the rational function to scrubbing noise theory is also indicated.

Oromandibular reconstruction with chimeric double-skin paddle flap based on peroneal vessel axis for synchronous opposite double oral cancer.

PubMed

Huang, Shih-Tsai; Liu, Wen-Chung; Chen, Lee-Wei; Yang, Kuo-Chung

2015-05-01

Synchronous double oral cancer represents the minority of cases of head and neck cancer. After tumor ablation, 2 separate oromandibular defects, even combined with a through-and-through oral defect, pose a serious reconstructive challenge. The ideal method for reconstruction remains controversial. Based on the peroneal vessel axis, a chimeric double-skin paddle peroneal fasciocutaneous or fibular osteomyocutaneous flap could be designed to accomplish the difficult reconstruction. Six male patients, each with 2 separate oromandibular defects after tumor ablation of synchronous double oral cancer, received double-skin paddle flap reconstruction with 3 peroneal fasciocutaneous and 3 fibular osteomyocutaneous flaps. All 6 flaps survived; however, complications included 1 skin paddle lost due to insufficient perfusion of a visible perforator, and 1 superficial necrosis occurring over the tip of a longer skin paddle. One postoperative intraoral infection and 1 donor site infection were also reported. During follow-up, 3 months later, 1 patient succumbed to local recurrence and bony metastasis. One patient developed a new cancer in the maxillary gingiva, and another had osteoradionecrosis 8 months later. Four patients gained acceptable cosmesis with good oral competence. A chimeric flap based on the peroneal artery could provide a segment of fibular bone, 1 or 2 skin paddles, and a cuff of the flexor hallucis longus muscle simultaneously. For 1-stage reconstruction of separate oromandibular defects after tumor ablation of synchronous double oral cancer, this design could provide all components at 1 transfer.

Optimizing Results of Postmastectomy Radiation Therapy Utilizing the Latissimus Dorsi Flap and Tissue Expander Technique: A Single-Center Experience

PubMed Central

Chevrollier, Guillaume S.; Greaney, Patrick J.; Jenkins, Matthew P.; Copit, Steven E.

2017-01-01

Objective: Postmastectomy radiation therapy is a well-established risk factor for complications after breast reconstruction. Even if the surgeon has a suspicion that radiation therapy may be needed, it may be beneficial to place tissue expanders during the mastectomy procedure as a temporizing measure, complete radiation therapy, and then reconstruct the breast with a latissimus flap. The purpose of this study was to examine the complication rates of the latissimus dorsi flap as compared with the complication rates of implant-based reconstruction in the setting of radiation therapy. Methods: A 16-year retrospective chart review from 2000 to 2016 was conducted. All patients who underwent temporizing tissue expander placement for radiotherapy with subsequent latissimus flap reconstruction were included in the study. Patients who did not follow up for implant exchange were excluded from the study. Results: Fifty-five patients were identified with an average age of 46.0 years (range, 27-67 years) and an average body mass index of 24.2 (range, 18.9-31.9). Five patients (9.1%) developed capsular contractures amenable to surgical intervention. One patient (1.8%) developed infection of the tissue expander, requiring removal. There were no incidences of flap failure or wound dehiscence. The average follow-up after latissimus flap reconstruction was 25.3 months (range, 3.7-121.6 months). Conclusions: We feel that the latissimus dorsi flap after postmastectomy radiation therapy represents the preferred implant-based reconstruction option to consider when the need for postmastectomy radiation therapy is anticipated. The latissimus dorsi flap remains a safe, effective solution to postmastectomy radiation therapy that every plastic surgeon should offer. PMID:29308108

Optimizing Results of Postmastectomy Radiation Therapy Utilizing the Latissimus Dorsi Flap and Tissue Expander Technique: A Single-Center Experience.

PubMed

Mohiuddin, Waseem; Chevrollier, Guillaume S; Greaney, Patrick J; Jenkins, Matthew P; Copit, Steven E

2017-01-01

Objective: Postmastectomy radiation therapy is a well-established risk factor for complications after breast reconstruction. Even if the surgeon has a suspicion that radiation therapy may be needed, it may be beneficial to place tissue expanders during the mastectomy procedure as a temporizing measure, complete radiation therapy, and then reconstruct the breast with a latissimus flap. The purpose of this study was to examine the complication rates of the latissimus dorsi flap as compared with the complication rates of implant-based reconstruction in the setting of radiation therapy. Methods: A 16-year retrospective chart review from 2000 to 2016 was conducted. All patients who underwent temporizing tissue expander placement for radiotherapy with subsequent latissimus flap reconstruction were included in the study. Patients who did not follow up for implant exchange were excluded from the study. Results: Fifty-five patients were identified with an average age of 46.0 years (range, 27-67 years) and an average body mass index of 24.2 (range, 18.9-31.9). Five patients (9.1%) developed capsular contractures amenable to surgical intervention. One patient (1.8%) developed infection of the tissue expander, requiring removal. There were no incidences of flap failure or wound dehiscence. The average follow-up after latissimus flap reconstruction was 25.3 months (range, 3.7-121.6 months). Conclusions: We feel that the latissimus dorsi flap after postmastectomy radiation therapy represents the preferred implant-based reconstruction option to consider when the need for postmastectomy radiation therapy is anticipated. The latissimus dorsi flap remains a safe, effective solution to postmastectomy radiation therapy that every plastic surgeon should offer.

The Sternocleidomastoid Muscle Flap: A Versatile Local Method for Repair of External Penetrating Injuries of Hypopharyngeal-Cervical Esophageal Funnel.

PubMed

Ellabban, Mohamed A

2016-04-01

A primary repair of external penetrating injury to hypopharyngeal-cervical esophageal (HP-CE) funnel without reinforcement has more complications if compared with muscle reinforcement. The aim of the present study was to assess the outcome of using sternocleidomastoid (SCM) muscle flap for reinforcement of primary repair of HP-CE funnel injury. The study proposed an algorithm for different uses of SCM flap repair according to site and size of funnel perforation. A prospective analysis of 12 patients, who had surgical treatment for external penetrating injuries of HP-CE funnel between January 2011 and September 2014, was recorded. The following factors were studied for each case: demographic data, Revised Trauma Score (RTS), mechanism of injury, time interval between injury and definitive surgical care, injury morphology, any associated injuries, technique of SCM flap used, length of hospital stay, and surgical outcome and complications. They were 10 males and 2 females and the mean age was 31.9 years. The cause of injury was stab wound in 5 (41.7 %) cases, gunshot injury in 4 (33.3 %) cases and 3 (25 %) cases after anterior cervical spine surgery. Isolated injury to HP and CE was recorded in 5 cases (41.7 %) for each site. However, 2 (16.7 %) cases had injury to both HP and CE. Cranially based SCM flap was mainly used in cases with HP injury and caudally based flap in CE cases with some limitations. The whole muscle flap was used in large (≥ 1 cm) defects while and the split muscle flap in small (<1 cm) defects. Oral intake started 7 days postoperatively with only one (8.3 %) case of small leakage, which was treated conservatively. The SCM flap is a very useful and versatile tool in reinforcement of HP-CE funnel injury with the advantages of high success rates of leakage prevention.

[Fasciocutaneous flap reliable by deep femoral artery perforator for the treatment of ischial pressure ulcers].

PubMed

Gebert, L; Boucher, F; Lari, A; Braye, F; Mojallal, A; Ismaïl, M

2018-04-01

The surgical management of pressure ulcers in the paraplegic or quadriplegic population is marked by the high risk of recurrence in the long-term. In the current era of perforator flaps, newer reconstructive options are available for the management of pressure ulcers, decreasing the need to use the classically described muscular or musculocutaneous locoregional flaps. The coverage of ischial sores described in this article by a pedicled flap based on a deep femoral artery perforator, appears to be an effective first-line reconstructive option for the management of limited size pressure ulcers. A number of fifteen paraplegic or quadriplegic patients having at least one ischial bed sore with underlying osteomyelitis were included in this series. The approximate location of the deep femoral artery perforator was initially identified using the "The Atlas of the perforator arteries of the skin, the trunk and limbs", which was confirmed, with the use of a Doppler device. A fasciocutaneous transposition flap was elevated, with the pivot point based on the cutaneous bridge centered on the perforator, and then transposed to cover the area of tissue loss. The donor site was closed primarily. A total of fifteen patients were operated from November 2015 to November 2016. The series comprised of 16 first presentations of a stage 4 pressure ulcers associated with underlying osteomyelitis that were subsequently reconstructed by the pedicled deep femoral artery perforator flap. The healing rate and functional results were both satisfactory. Fasciocutaneous flap reliable by deep femoral artery perforator appears to have a promising role in the treatment of ischial pressure sores. It is an attractive option to spare the use of musculocutaneous flaps in the area. Thus this flap could be used as a first-line option to cover ischial pressure ulcers of limited size. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Applying the Keystone Design Perforator Island Flap Concept in a Variety of Anatomic Locations: A Review of 60 Consecutive Cases by a Single Surgeon.

PubMed

Lanni, Michael Alan; Van Kouwenberg, Emily; Yan, Alan; Rezak, Kristen M; Patel, Ashit

2017-07-01

The keystone design perforator island flap has been gaining popularity for reconstruction of cutaneous defects. Published experience of this technique in North America is limited predominantly to the trunk and extremities; our study aims to demonstrate expanding applications. Retrospective chart review was conducted on all patients who underwent keystone flap reconstruction by a single surgeon. Outcomes of interest were wound healing complications (WHC) and surgical site infections (SSI). Mean follow up time was 24.4 months. Sixty consecutive flaps were performed with an overall WHC rate of 26.7% and SSI rate of 11.7%. Reconstructed sites included 25 lower extremity, 20 trunk, 5 upper extremity, and 10 head and neck. Flap size averaged 405.6 cm (range 16-2303). Wound healing complications were associated with coronary artery disease (P = 0.04) and traumatic defects (P = 0.043). Surgical site infections were associated with coronary artery disease (P = 0.02) and flap size of 251 to 500 cm (P = 0.039), although this association was not seen among flaps greater than 500 cm. Although more common in lower extremity reconstructions, no statistically significant associations between flap location and WHC (P = 0.055) or SSI (P = 0.29) were identified. There were no reconstructive failures and no patients required reoperation. This series demonstrates the versatility of the keystone flap in a wide variety of anatomic locations, with similar complication rates to those previously reported and no reoperations. Flap design was frequently modified based on the anatomical topography and adjacent subunits. To our knowledge, this is the largest and most diverse North American series of keystone flap reconstructions to date.

Inferior-based pharyngeal flap for correction of stress velopharyngeal incompetence in musicians: case reports and review of the literature.

PubMed

Visser, A; van der Biezen, J J

2012-07-01

Stress velopharyngeal incompetence (SVPI) is a special form of velopharyngeal incompetence observed in musicians who play wind and brass instruments. Due to high intraoral pressures generated while playing, the velopharyngeal structures fail to seal off the nasopharynx properly, resulting in unwanted nasal air leakage or noises. We present two young female professional clarinetists who experience symptoms of SVPI that preclude the development of their professional career. Both musicians underwent an inferior based pharyngeal flap, a well-known flap frequently used in cleft palate surgery. Both musicians were symptom-free after surgery and remain free of nasal noises while playing the clarinet after 2 and 4 years of follow-up. We present a review of literature of management of SVPI and show that the inferior-based pharyngeal flap is a feasible option for management of these potentially career ending symptoms. Copyright © 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Reconstruction of the vulva with sensate gluteal fold flaps.

PubMed

Kuokkanen, H; Mikkola, A; Nyberg, R H; Vuento, M H; Kaartinen, I; Kuoppala, T

2013-01-01

Soft-tissue reconstruction of the vulva following resection of malignancies is challenging. The function of perineal organs should be preserved and the reconstructed area should maintain an acceptable cosmetic appearance. Reconstruction with local flaps is usually sufficient in the primary phase after a radical vulvectomy. Numerous flaps have been designed for vulvar reconstruction usually based on circulation from the internal pudendal artery branches. In this paper we introduce our modification of the gluteal fold V-Y advancement flap as a primary reconstruction after a radical vulvectomy. Twenty-two patients were operated with a radical vulvectomy because of vulvar malignancies. The operation was primary in eight and secondary in 14 patients. The reconstruction of the vulva was performed in the same operation for each patient. All flaps survived completely. Wound complications were registered in three patients. Late problems with urinary stream were corrected in two patients. A local recurrence of the malignancy was observed in six patients during the follow-up period. Gluteal fold flap is easy to perform, has a low rate of complications and gives good functional results. Even a large defect can be reconstructed reliably with this method. A gluteal fold V-Y advancement flap is sensate and our modification allows the flap to be transposed with lesser dissection as presented before.

A comparison of techniques for myelomeningocele defect closure in the neonatal period.

PubMed

Kobraei, Edward M; Ricci, Joseph A; Vasconez, Henry C; Rinker, Brian D

2014-09-01

Numerous techniques have been described for repair of myelomeningoceles, but outcome data is scarce. A retrospective review was performed in 32 consecutive patients who underwent neonatal myelomeningocele repair and extra-dural closure to determine the influence of repair type on outcome. All procedures for myelomeningocele closure were classified into one of three groups, which included primary closure, myocutaneous flaps, and fasciocutaneous flaps. Defect size ranged from 1 to 48 cm(2). Primary skin closure was performed in 3 patients, fasciocutaneous flaps in 13 patients, and myocutaneous flaps in 16 patients. The overall complication rate was 18%. No difference in the complication rates among the primary closure, myocutaneous, and fasciocutaneous flap groups was observed in our analysis. While not statistically significant, our data documents an association of fasciocutaneous flaps with postoperative complications that were not evident with primary skin closure or myocutaneous flaps (odds ratio 3.8; p = 0.15). The occurrence of one or more complications was associated with a longer hospital stay. Myocutaneous flaps provide a secure repair and should be considered for smaller myelomeningocele defects in addition to the larger defects where they are more traditionally used. We propose a tissue-based classification of closure techniques strictly for multi-institution outcome comparison that may ultimately inform clinical decision-making.

[Clinical effect of distally-based dorsal thumb neurocutaneous vascular flap on repair of soft tissue defect in thumb].

PubMed

Huang, Yixiong; Shen, Zunli; Wang, Yongchun; Zhang, Shimin

2009-10-01

To investigate the surgical methods and clinical results of repairing soft tissue defects in the thumb with distally-based dorsal thumb neurocutaneous vascular flap. From January 2006 to October 2007, 23 patients with soft tissue defect in the thumb were treated, including 20 males and 3 females aged 19-46 years old (average 27.5 years old). The defect was caused by crush injury in 1 case, electric planer accident in 6 cases, incised injury in 8 cases, and avulsion injury in 8 cases. The defect was located on the palmar aspect of the thumb distal phalanx in 3 cases, the dorsal-radial aspect of the thumb distal phalanx in 3 cases, and ulnar or dorsal aspect in 17 cases. The defect size ranged from 3.3 cm x 1.2 cm to 4.2 cm x 1.2 cm. Among them, 18 cases were complicated with distal 1/2 nail bed defect or injury. The time between injury and hospital admission was 1-72 hours (average 22 hours). During operation, the defect was repaired with distally-based dorsal-radial neurovenocutaneous vascular flap of the thumb in 3 cases and distally-based dorsal-ulnar neurovenocutaneous vascular flap of the thumb in 20 cases. The size of those flaps was 4.0 cm x 1.6 cm-5.0 cm x 3.0 cm. The donor site underwent direct suture or split thickness skin graft repair. At 10 days after operation, 3 cases suffered from the epidermal necrosis in the distal part of the flap, 2 of them experienced the exfoliation of dark scab 14 days later and the flap survived, and the flap of the rest one survived after dressing change. The other flaps and the skin graft at the donor site all survived uneventfully. The wounds healed by first intention. All the patients were followed up for 10-16 months (average 12.6 months). The flaps were soft in texture and full in appearance. The two-point discrimination value 6 months after operation was 8-10 mm. At 12 months after operation, the growth of the residual fingernail was evident in 18 cases, including 4 cases of curved or hook fingernail. Active flexion and extension of the thumb were normal. The abduction of the first web space reached or surpassed 80 percent of the normal side in 20 cases and was below 80 percent of the normal side in 3 cases. The clinical outcomes were satisfactory in 11 cases, approximately satisfactory in 8 cases, and unsatisfactory in 4 cases according to self-designed evaluation system. The operative method of repairing the soft tissue defects in the thumb with the distally-based dorsal thumb neurocutaneous vascular flap is simple, stable in anatomy, in line with the principle of proximity, and suitable for repairing thumb tip defect 3 cm in size. It can bring a good postoperative appearance of the thumb and little influence on the hand function.

Electric sail space flight dynamics and controls

NASA Astrophysics Data System (ADS)

Montalvo, Carlos; Wiegmann, Bruce

2018-07-01

This paper seeks to investigate the space flight dynamics of a rotating barbell Electric Sail (E-Sail). This E-Sail contains two 6U CubeSats connected to 8 km tethers joined at a central hub. The central hub is designed to be an insulator so that each tether can have differing voltages. An electron gun positively charges each tether which interacts with the solar wind to produce acceleration. If the voltage on each tether is different, the trajectory of the system can be altered. Flapping modes and tension spikes are found during many of these maneuvers and care must be taken to mitigate the magnitude of these oscillations. Using sinusoidal voltage inputs, it is possible to control the trajectory of this two-body E-Sail and propel the system to Near-Earth-Objects or even deep space.

Interstrand disulfide crosslinking of DNA bases supports a double nucleotide unpairing mechanism for flap endonucleases.

PubMed

Beddows, Amanda; Patel, Nikesh; Finger, L David; Atack, John M; Williams, David M; Grasby, Jane A

2012-09-14

Flap endonucleases (FENs) are proposed to select their target phosphate diester by unpairing the two terminal nucleotides of duplex. Interstrand disulfide crosslinks, introduced by oxidation of thiouracil and thioguanine bases, abolished the specificity of human FEN1 for hydrolysis one nucleotide into the 5'-duplex.

Postburn Neck Reconstruction With Preexpanded Upper Back Perforator Flaps: Free-Style Design and An Update of Treatment Strategies.

PubMed

Li, Haizhou; Wang, Zi; Gu, Bin; Gao, Yashan; Xie, Feng; Zhu, Hainan; Li, Qingfeng; Zan, Tao

2018-05-14

For extensive postburn neck deformities, the preexpanded flaps in the upper back region were used and gained a uniform skin appearance and esthetic contours. Free-style perforator-based free-tissue transfer that represents the most recent advance in reconstructive surgery may provide more versatility of these flaps. We retrospectively reviewed 31 patients treated at our institution for postburn neck contracture from March 2010 to May 2016. Various upper back flaps were designed according to the dominant perforators and the shape of the defect after fully releasing the neck contracture. Thirty-one patients received neck reconstructions with the versatile applications of the preexpanded upper back perforator flaps. Tip necrosis was observed in one case, and the others survived completely. The donor sites were all primarily closed. No incision dehiscence was observed. The free-style design has significantly increased the potential and versatility of the upper back flaps in reconstruction of severe neck scar contracture.

The Influence of Scleral Flap Thickness, Shape, and Sutures on Intraocular Pressure (IOP) and Aqueous Humor Flow Direction in a Trabeculectomy Model.

PubMed

Samsudin, Amir; Eames, Ian; Brocchini, Steve; Khaw, Peng Tee

2016-07-01

Intraocular pressure and aqueous humor flow direction determined by the scleral flap immediately after trabeculectomy are critical determinants of the surgical outcome. We used a large-scale model to objectively measure the influence of flap thickness and shape, and suture number and position on pressure difference across the flap and flow of fluid underneath it. The model exploits the principle of dynamic and geometric similarity, so while dimensions were up to 30× greater than actual, the flow had similar properties. Scleral flaps were represented by transparent 0.8- and 1.6-mm-thick silicone sheets on an acrylic plate. Dyed 98% glycerin, representing the aqueous humor was pumped between the sheet and plate, and the equilibrium pressure measured with a pressure transducer. Image analysis based on the principle of dye dilution was performed using MATLAB software. The pressure drop across the flap was larger with thinner flaps, due to reduced rigidity and resistance. Doubling the surface area of flaps and reducing the number of sutures from 5 to 3 or 2 also resulted in larger pressure drops. Flow direction was affected mainly by suture number and position, it was less toward the sutures and more toward the nearest free edge of the flap. Posterior flow of aqueous humor was promoted by placing sutures along the sides while leaving the posterior edge free. We demonstrate a new physical model which shows how changes in scleral flap thickness and shape, and suture number and position affect pressure and flow in a trabeculectomy.

Are prostaglandins or calcium channel blockers efficient for free flap salvage? A review of the literature.

PubMed

Huby, M; Rem, K; Moris, V; Guillier, D; Revol, M; Cristofari, S

2018-03-01

The free flap failure rate is less than 5%. The responsible mechanisms of postoperative secondary ischemia are mostly vascular. The main postoperative complication leading to flap failure is thrombosis. Different strategies have been reported to improve the reliability of flaps and decrease the risk of partial or total necrosis: thus, pharmacologic agents have been studied to reduce the risk of microvascular thrombosis. The aim of this review was to evaluate the effect of calcium channel blockers and prostaglandins on free skin flap survival. A systematic review of the literature was performed to identify articles studying the efficacy of calcium channel blockers and prostaglandins on free flap survival. After full text reading, eleven articles were finally included. Eight articles investigated the role of prostaglandins in free tissue transfers, two in rats subjects, one in rabbits, five in humans. Two articles studied the effect of calcium channel blockers on free flaps, one in rats subjects, one in rabbits. One article studied in different groups the effect of calcium channel blockers and prostaglandins on free flaps in rabbits. Literature regarding the efficacy of calcium channel blockers and prostaglandins to salvage free flap is poor and mainly based on animal models. Nevertheless, studies on prostaglandins showed a slight efficiency of these molecules for free flap salvage. Results are less reliable for calcium channel blockers and dependent on the molecule used. In conclusion, there is a lack of evidence to use them in clinical practice. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Propellant Readiness Level: A Methodological Approach to Propellant Characterization

NASA Technical Reports Server (NTRS)

Bossard, John A.; Rhys, Noah O.

2010-01-01

A methodological approach to defining propellant characterization is presented. The method is based on the well-established Technology Readiness Level nomenclature. This approach establishes the Propellant Readiness Level as a metric for ascertaining the readiness of a propellant or a propellant combination by evaluating the following set of propellant characteristics: thermodynamic data, toxicity, applications, combustion data, heat transfer data, material compatibility, analytical prediction modeling, injector/chamber geometry, pressurization, ignition, combustion stability, system storability, qualification testing, and flight capability. The methodology is meant to be applicable to all propellants or propellant combinations; liquid, solid, and gaseous propellants as well as monopropellants and propellant combinations are equally served. The functionality of the proposed approach is tested through the evaluation and comparison of an example set of hydrocarbon fuels.

Computational Predictions of the Performance Wright 'Bent End' Propellers

NASA Technical Reports Server (NTRS)

Wang, Xiang-Yu; Ash, Robert L.; Bobbitt, Percy J.; Prior, Edwin (Technical Monitor)

2002-01-01

Computational analysis of two 1911 Wright brothers 'Bent End' wooden propeller reproductions have been performed and compared with experimental test results from the Langley Full Scale Wind Tunnel. The purpose of the analysis was to check the consistency of the experimental results and to validate the reliability of the tests. This report is one part of the project on the propeller performance research of the Wright 'Bent End' propellers, intend to document the Wright brothers' pioneering propeller design contributions. Two computer codes were used in the computational predictions. The FLO-MG Navier-Stokes code is a CFD (Computational Fluid Dynamics) code based on the Navier-Stokes Equations. It is mainly used to compute the lift coefficient and the drag coefficient at specified angles of attack at different radii. Those calculated data are the intermediate results of the computation and a part of the necessary input for the Propeller Design Analysis Code (based on Adkins and Libeck method), which is a propeller design code used to compute the propeller thrust coefficient, the propeller power coefficient and the propeller propulsive efficiency.

Transversus Abdominis Plane Blocks with Single-Dose Liposomal Bupivacaine in Conjunction with a Nonnarcotic Pain Regimen Help Reduce Length of Stay following Abdominally Based Microsurgical Breast Reconstruction.

PubMed

Jablonka, Eric M; Lamelas, Andreas M; Kim, Julie N; Molina, Bianca; Molina, Nathan; Okwali, Michelle; Samson, William; Sultan, Mark R; Dayan, Joseph H; Smith, Mark L

2017-08-01

Side effects associated with use of postoperative narcotics for pain control can delay recovery after abdominally based microsurgical breast reconstruction. The authors evaluated a nonnarcotic pain control regimen in conjunction with bilateral transversus abdominis plane blocks on facilitating early hospital discharge. A retrospective analysis was performed of consecutive patients who underwent breast reconstruction using abdominally based free flaps, with or without being included in a nonnarcotic protocol using intraoperative transversus abdominis plane blockade. During this period, the use of locoregional analgesia evolved from none (control), to continuous bupivacaine infusion transversus abdominis plane and catheters, to single-dose transversus abdominis plane blockade with liposomal bupivacaine solution. Demographic factors, length of stay, inpatient opioid consumption, and complications were reported for all three groups. One hundred twenty-eight consecutive patients (182 flaps) were identified. Forty patients (62 flaps) were in the infusion-liposomal bupivacaine group, 48 (66 flaps) were in the single-dose blockade-catheter group, and 40 (54 flaps) were in the control group. The infusion-liposomal bupivacaine patients had a significantly shorter hospital stay compared with the single-dose blockade-catheter group (2.65 ± 0.66 versus 3.52 ± 0.92 days; p < 0.0001) and the control group (2.65 ± 0.66 versus 4.05 ± 1.26 days; p < 0.0001). There was no significant difference in flap loss or major complications among groups. When used as part of a nonnarcotic postoperative pain regimen, transversus abdominis plane blocks performed with single injections of liposomal bupivacaine help facilitate early hospital discharge after abdominally based microsurgical breast reconstruction. A trend toward consistent discharge by postoperative day 2 was seen. This could result in significant cost savings for health care systems. Therapeutic, III.

Versatility of Subscapular Chimeric Free Flaps in the Secondary Reconstruction of Composite Posttraumatic Defects of the Upper Face

PubMed Central

Stalder, Mark Winston; Wise, Matthew Whitten; Dupin, Charles L.; St Hilaire, Hugo

2014-01-01

High energy injuries to the upper face present challenging reconstructive problems. In some cases, initial reconstructive efforts result in unfavorable outcomes that require secondary intervention. Chimeric free flaps based on the subscapular system offer the tissue components and volume needed for these complex reconstructions. This is a series of five patients who underwent secondary reconstruction of the middle and upper face following traumatic injury. Mechanism of injury, prior attempts at reconstruction, and characteristics of the tissue defects and the flaps used in their reconstruction are described. Two patients were female and three were male. Three injuries resulted from gunshot wounds, and two from motor vehicle accidents. All patients had multiple prior failed attempts at reconstruction using local/regional tissue. Defects included symptomatic oronasal or oro-orbital fistulas, enophthalmos, and forehead contour deformities. Two of the flaps used included scapular bone and latissimus muscular components, and three included scapular bone and thoracodorsal artery perforator-based skin paddle components. All free tissue transfers were successful, and no patients suffered significant complications. Chimeric free flaps based on the subscapular system offer a valuable secondary strategy for reconstruction of composite defects of the upper face when other options have been exhausted through previous efforts. PMID:25709752

Folding in and out: passive morphing in flapping wings.

PubMed

Stowers, Amanda K; Lentink, David

2015-03-25

We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover within a beat.

Latissimus Dorsi Flap in Breast Reconstruction

PubMed Central

Sood, Rachita; Easow, Jeena M.; Konopka, Geoffrey; Panthaki, Zubin J.

2018-01-01

Background: Surgeons employ the latissimus dorsi flap (LDF) for reconstruction of a large variety of breast cancer surgery defects, including quadrantectomy, lumpectomy, modified radical mastectomy, and others. The LDF may be used in delayed or immediate reconstruction, in combination with tissue expanders for a staged reconstruction, with implant-based immediate reconstruction, or alone as an autogenous flap. Methods: The authors discuss the historical uses and more recent developments in the LDF. More recent advancements, including the “scarless” approach and augmentation with the thoracodorsal artery perforator flap, are discussed. Results: The LDF is a reliable means for soft tissue coverage providing form and function during breast reconstruction with acceptable perioperative and long-term morbidities. Conclusions: When there is a paucity of tissue, the LDF can provide tissue volume in autologous reconstruction, as well as a reliable vascular pedicle for implant-based reconstruction as in the setting of irradiated tissue. PMID:29334788

Perforator Peroneal Artery Flap for Tongue Reconstruction.

PubMed

Chauhan, Shubhra; Chavre, Sachin; Chandrashekar, Naveen Hedne; B S, Naveen

2017-03-01

Reconstruction has evolved long way from primary closure to flaps. As time evolved, better understanding of vascularity of flap has led to the development of innovative reconstructive techniques. These flaps can be raised from various parts of the body for reconstruction and have shown least donor site morbidity. We use one such peroneal artery perforator flap for tongue reconstruction with advantage of thin pliable flap, minimal donor site morbidity and hidden scar. Our patient 57yrs old lady underwent wide local excision with selective neck dissection. Perforators are marked about 10 and 15 cm inferiorly from the fibular head using hand held Doppler. Leg is positioned in such a way to give better exposure during dissection of the flap and flap is harvested under a tourniquet with pressure kept 350 mm Hg. The perforator is kept at the eccentric location, so as to gain length of the pedicle. Skin incison is placed over the peroneal muscle and deepened unto the deep facia, then the dissection is continued over the muscle and the perforator arising from the lateral septum. The proximal perforator about 10 cm from the fibular head is a constant perforator and bigger one, which is traced up to the peroneal vessel. We could get a 6 cm of pedicle length. Finally the flap is islanded on this perforator and the pedicle is ligated and flap harvested. Anastamosis was done to the ipsilateral side to facial vessels. The donor site is closed primarily and in the upper half one can harvest 5 cm width flap without requiring a skin graft along with a length of 8 to 12 cm. Various local and free flap has been used for reconstruction of partial tongue defects with its obvious donor site problems, like less pliable skin and not so adequate tissue from local flaps and sacrificing a important artery as in radial forearm flap serves as the work horse in reconstruction of partial tongue defects, Concept of super microsurgery was popularized by Japanese in 1980s and the concept of angiosome proposed by Taylor paved the way for development of new flaps. True perforator flaps are those where the source vessel is left undisturbed and overlying skin flap is raised. Yoshimura proposed cutaneous flap could be raised from peroneal artery (Br J Plast Surg 42:715-718, 1989). Wolff et al. (Plast Reconstr Surg 113:107-113, 2004) first used perforator based peroneal artery flap for oral reconstruction. Location of perforators vary, hence pre operative localisation can be done by ultrasound doppler, CT angio or MR angiography. Disadvantages over radial flap include varying anatomic location of perforators, need for imaging and difficult dissection of delicate vessels through muscles and hence a learning curve. Our patient had an arterial thrombus within few hours post-operatively which was successfully salvaged with immediate re-exploration and re-anastomosis of artery. Post-operative healing was uneventful and donor site was closed primarily without the need for graft. Perforator peroneal flap serves as a useful armamentarium for reconstruction of moderate size defects of tongue, buccal mucosa and floor of mouth with advantages of thin pliable flap, minimal donor site morbidity and hidden scar.

Testing Momentum Enhancement of Ribbon Fin Based Propulsion Using a Robotic Model With an Adjustable Body

NASA Astrophysics Data System (ADS)

English, Ian; Curet, Oscar

2016-11-01

Lighthill and Blake's 1990 momentum enhancement theory suggests there is a multiplicative propulsive effect linked to the ratio of body and fin heights in Gymnotiform and Balistiform swimmers, which propel themselves using multi-rayed undulating fins while keeping their bodies mostly rigid. Proof of such a momentum enhancement could have a profound effect on unmanned underwater vehicle design and shed light on the evolutionary advantage to body-fin ratios found in nature, shown as optimal for momentum enhancement in Lighthill and Blake's theory. A robotic ribbon fin with twelve independent fin rays, elastic fin membrane, and a body of adjustable height was developed specifically to experimentally test momentum enhancement. Thrust tests for various body heights were conducted in a recirculating flow tank at different flow speeds and fin flapping frequencies. When comparing thrust at different body heights, flow speeds, and frequencies to a 'no-body' thrust test case at each frequency and flow speed, data indicate there is no momentum enhancement factor due to the presence of a body on top of an undulating fin. This suggests that if there is a benefit to a specific ratio between body and fin height, it is not due to momentum enhancement.

Effect of limited amplitude and rate of flap motion on vane-controlled gust alleviation system

NASA Technical Reports Server (NTRS)

Barker, L. K.; Crawford, D. J.; Sparrow, G. W.

1972-01-01

An airplane (light transport type) is assumed to be in level flight (no pitching) through atmospheric turbulence which has a mean-square vertical gust intensity of 9.3 (m/sec)sq. The power spectral density of the vertical acceleration due to gusts is examined with and without a gust-alleviation system in operation. The gust-alleviation system consisted of wing flaps that were used in conjunction with a vane mounted ahead of the airplane to sense the vertical gust velocity. The primary purpose of this study was to examine the change in the effectiveness of the gust-alleviation system when the flap motion is limited in amplitude and rate. The alleviation system was very effective if no restrictions were placed on flap motion (rate and amplitude). Restricting the flap amplitude to 0.5 radian did not appreciably change the effectiveness. However, restricting the flap rate did reduce the gust alleviation, and restricting the flap rate to 0.25 rad/sec actually caused the alleviation system to increase the vertical acceleration above that for the no-alleviation situation. Based upon this analysis, rate limiting appears to be rather significant in gust-alleviation systems designed for passenger comfort.

Reverse-flow retroauricular island flap in facial reconstruction.

PubMed

Benlier, Erol; Top, Husamettin; Cinar, Can; Yazar, Sukru; Aygit, A Cemal; Cetinkale, Oguz

2007-12-01

Reconstruction of facial skin defects requires good-quality skin cover to satisfy aesthetic expectations of patient, especially when the skin defect is on the uncovered area of the face. Limitations in the available local tissue and donor-site morbidity restrict the options. In an effort to solve these problems, we have begun to use a subcutaneous pedicled retroauricular reverse-flow flap. Between January 1997 and December 2005, reverse-flow subcutaneous pedicled retroauricular island flap was used to cover facial defects in 12 patients who underwent surgical excision of skin tumor. The patients ranged in age from 44 to 81 years with a mean age of 58 years. Only one case experienced a superficial necrosis in the distal one-quarter part of the flap. The functional and aesthetic results were satisfactory for both patients and surgeons, and no tumor recurrence was observed during the 12 to 28 months (mean, 18.8 months) follow-up period. This flap can be used reliably for the reconstruction of facial skin defects of small and medium size. The preference of frontal branch pedicled flap enables more distal facial area defects to be covered, such as dorsal nasal, nasolabial, and upper lip, than flaps based on parietal branch.

Deep Sternal Wound Infection after Open-Heart Surgery: A 13-Year Single Institution Analysis.

PubMed

Juhl, Alexander Andersen; Hody, Sofie; Videbaek, Tina Senholt; Damsgaard, Tine Engberg; Nielsen, Per Hostrup

2017-04-20

The present study aimed to compare the clinical outcome for patients with or without muscle flap reconstruction after deep sternal wound infection due to open-heart surgery. The study was a retrospective cohort study, including patients who developed deep sternal wound infection after open-heart surgery in the Western Denmark Region from 1999 to 2011. Journals of included patients were reviewed for clinical data regarding the treatment of their sternal defect. Patients were divided into two groups depending on whether they received a muscle-flap-based sternal reconstruction or traditional rewiring of the sternum. A total of 130 patients developed deep sternal wound infection in the study period. In all, 12 patients died before being discharged, leaving a total of 118 patients for analysis. Of these, 50 (42%) patients received muscle flap reconstruction. Muscle flap recipients had significantly longer total hospital stays (p <0.001). However, after receiving muscle flap reconstruction, patients were discharged after a median of 14 days, with 74% not needing additional surgery. It is difficult to predict which patients eventually require muscle flap reconstruction after deep sternal wound infection. Although patients receiving muscle flap reconstructions have longer hospital stays, they are quickly discharged after the reconstruction.

Effect of two laser photobiomodulation application protocols on the viability of random skin flap in rats

NASA Astrophysics Data System (ADS)

Martignago, C. C. S. M.; Tim, C. R.; Assis, L.; Neve, L. M. G.; Bossini, P. S.; Renno, A. C.; Avó, L. R. S.; Liebano, R. E.; Parizotto, N. A.

2018-02-01

Objective: to identify the best low intensity laser photobiomodulation application site to increase the viability of the cutaneous flap in rats. Methods: 18 male rats (Rattus norvegicus: var. Albinus, Rodentia Mammalia) were randomly distributed into 3 groups (n = 6). Group I (GI) was submitted to simulated laser photobiomodulation, group II (GII) was submitted to the laser photobiomodulation at three points in the flap cranial base, and group III (GIII) was submitted to laser photobiomodulation at twelve points distributed along the flap. All groups were irradiated with an Indium, Galium, Aluminum and Phosphorus diode laser (InGaAlP), 660 nm, with power of 50 mW, total energy of 12 J in continuous emission mode. The treatment started immediately after performing the cranial base random skin flap (dimension of 10X4 cm2 ) and reapplied every 24 hours, with a total of 5 applications. The animals were euthanized after the evaluation of the percentage of necrosis area and the material was collected for histological analysis on the 7th postoperative day. Results: GII animals presented a statistically significant decrease for the necrosis area when compared to the other groups, and a statistically significant increase in the quantification of collagen when compared to the control. We did not observe a statistical difference between the TGFβ and FGF expression in the different groups evaluated. Conclusion: the application of laser photobiomodulation at three points of the flap cranial base was more effective than at twelve points regarding the reduction of necrosis area.

Study of the length of hospital stay for free flap reconstruction of oral and pharyngeal cancer in the context of the new French casemix-based funding.

PubMed

Girod, Angélique; Brancati, Antonio; Mosseri, Véronique; Kriegel, Irène; Jouffroy, Thomas; Rodriguez, José

2010-03-01

The French national health insurance reimbursement system has recently changed from a global hospital funding system to casemix-based funding. The authors studied the factors likely to influence the length of hospital stay for free flap reconstructions after surgery for cancers of the oral cavity or pharynx. Data concerning 207 oral cavity or pharynx free flap reconstructions were extracted from a prospective registration. Lengths of hospital stay were compared by an analysis of variance F test or a nonparametric Kruskal-Wallis test, and transfusion rates were compared by Chi-square test or Fisher's exact test, as appropriate. The median length of hospital stay was 24 days (range: 7-145 days). Length of hospital stay was significantly longer according to the type of flap (p<0.005), in N2-N3 patients (p<0.02), a PINI score more than 10, a 3-4 American Society of Anesthesiologists (ASA) score, the presence of a tracheotomy and in patients requiring transfusion (p<0.0001). As the nodal status, the American Society of Anesthesiologists (ASA) score of the patient, the need of tracheotomy and the type of flap cannot be corrected, the management of preoperative haemoglobin and nutritional status are the sole factors which can improve the length of hospital stay. In the context of the new casemix-based funding, this study raises the problem of harvesting of the fibula flap, management of preoperative haemoglobin and nutritional status. (c) 2009 Elsevier Ltd. All rights reserved.

Numerical investigation of the aerodynamic loads and hinge moments of the flap with boundary layer control

NASA Astrophysics Data System (ADS)

Pavlenko, Olga V.; Pigusov, Evgeny A.

2018-05-01

The paper discusses the approach of numerical simulation of the boundary layer control (BLC) on deflected flap for suppression of flow separation. Computational investigations were carried out using a program based on numerically solving the Reynolds averaged Navier-Stokes equations. The aim of this work is numerical investigation of the aerodynamic loads and hinge moments of the flap with BLC with influence of the walls of the wind tunnel. We have made a calculation of the airfoil section with flap deflected by 20° and 60° with variation of blowing momentum coefficient of Cμ=0÷0.1. The comparison of the calculation results with the experimental values of lift coefficient, pitching moment and pressure coefficient is presented. The pressure distribution on all surface of the wing and the threedimensional flow pattern of the wing with BLC, influence of the walls of the wind tunnel and the aerodynamic loads and hinge moments of the BLC flap are given. It is shown that the 20° flap increases the jet momentum coefficient from Cμ=0 to Cμ=0.1, leads to an increase of the hinge moment coefficient almost in 2 times, and the 60° flap increases the jet momentum coefficient from Cμ=0 to Cμ=0.113, leads to an increase of the hinge moment coefficient almost 3.5 times. The magnitude of the hinge moment on the flap with BLC rises due to the increase of the total aerodynamic force acting on the flap. As a result, the jet blowing on the plain flap leads to the significant increase of the hinge moment that must be considered when designing the high-lift devices with BLC.

[The sural medial perforator flap: Anatomical bases, surgical technique and indications in head and neck reconstruction].

PubMed

Struk, S; Schaff, J-B; Qassemyar, Q

2018-04-01

The medial sural artery perforator (MSAP) flap is defined as a thin cutaneo-adipose perforator flap harvested on the medial aspect of the leg. The aims of this study were to describe the anatomical basis as well as the surgical technique and discuss the indications in head and neck reconstructive surgery. We harvested 10 MSAP flap on 5 fresh cadavers. For each case, the number and the location of the perforators were recorded. For each flap, the length of pedicle, the diameter of source vessels and the thickness of the flap were studied. Finally, we performed a clinical application of a MSAP flap. A total of 23 perforators with a diameter superior than 1mm were dissected on 10 legs. The medial sural artery provided between 1 and 4 musculocutaneous perforators. Perforators were located in average at 10.3cm±2cm from the popliteal fossa and at 3.6cm±1cm from the median line of the calf. The mean pedicle length was 12.1cm±2.5cm. At its origin, the source artery diameter was 1.8mm±0.25mm and source veins diameters were 2.45mm±0.9mm in average. There was no complication in our clinical application. This study confirms the reliability of previous anatomical descriptions of the medial sural artery perforator flap. This flap was reported as thin and particularly adapted for oral cavity reconstruction and for facial or limb resurfacing. Sequelae might be reduced as compared to those of the radial forearm flap with comparable results. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Three-dimensional Reconstruction of Scar Contracture-bearing Axilla and Digital Webs Using the Square Flap Method.

PubMed

Huang, Chenyu; Ogawa, Rei

2014-05-01

Joint scar contractures are characterized by tight bands of soft tissue that bridge the 2 ends of the joint like a web. Classical treatment methods such as Z-plasties are mainly based on 2-dimensional designs. Our square flap method is an alternative surgical method that restores the span of the web in a stereometric fashion, thereby reconstructing joint function. In total, 20 Japanese patients with joint scar contractures on the axillary (n = 10) or first digital web (n = 10) underwent square flap surgery. The maximum range of motion and commissure length were measured before and after surgery. A theoretical stereometric geometrical model of the square flap was established to compare it to the classical single (60 degree), 4-flap (45 degree), and 5-flap (60 degree) Z-plasties in terms of theoretical web reconstruction efficacy. All cases achieved 100% contracture release. The maximum range of motion and web space improved after square flap surgery (P = 0.001). Stereometric geometrical modeling revealed that the standard square flap (α = 45 degree; β = 90 degree) yields a larger flap area, length/width ratio, and postsurgical commissure length than the Z-plasties. It can also be adapted by varying angles α and β, although certain angle thresholds must be met to obtain the stereometric advantages of this method. When used to treat joint scar contractures, the square flap method can fully span the web space in a stereometric manner, thus yielding a close-to-original shape and function. Compared with the classical Z-plasties, it also provides sufficient anatomical blood supply while imposing the least physiological tension on the adjacent skin.

Three-dimensional Reconstruction of Scar Contracture-bearing Axilla and Digital Webs Using the Square Flap Method

PubMed Central

Huang, Chenyu

2014-01-01

Background: Joint scar contractures are characterized by tight bands of soft tissue that bridge the 2 ends of the joint like a web. Classical treatment methods such as Z-plasties are mainly based on 2-dimensional designs. Our square flap method is an alternative surgical method that restores the span of the web in a stereometric fashion, thereby reconstructing joint function. Methods: In total, 20 Japanese patients with joint scar contractures on the axillary (n = 10) or first digital web (n = 10) underwent square flap surgery. The maximum range of motion and commissure length were measured before and after surgery. A theoretical stereometric geometrical model of the square flap was established to compare it to the classical single (60 degree), 4-flap (45 degree), and 5-flap (60 degree) Z-plasties in terms of theoretical web reconstruction efficacy. Results: All cases achieved 100% contracture release. The maximum range of motion and web space improved after square flap surgery (P = 0.001). Stereometric geometrical modeling revealed that the standard square flap (α = 45 degree; β = 90 degree) yields a larger flap area, length/width ratio, and postsurgical commissure length than the Z-plasties. It can also be adapted by varying angles α and β, although certain angle thresholds must be met to obtain the stereometric advantages of this method. Conclusions: When used to treat joint scar contractures, the square flap method can fully span the web space in a stereometric manner, thus yielding a close-to-original shape and function. Compared with the classical Z-plasties, it also provides sufficient anatomical blood supply while imposing the least physiological tension on the adjacent skin. PMID:25289342

The posterior nasoseptal flap: A novel technique for closure after endoscopic transsphenoidal resection of pituitary adenomas

PubMed Central

Barger, James; Siow, Matthew; Kader, Michael; Phillips, Katherine; Fatterpekar, Girish; Kleinberg, David; Zagzag, David; Sen, Chandranath; Golfinos, John G.; Lebowitz, Richard; Placantonakis, Dimitris G.

2018-01-01

Background: While effective for the repair of large skull base defects, the Hadad-Bassagasteguy nasoseptal flap increases operative time and can result in a several-week period of postoperative crusting during re-mucosalization of the denuded nasal septum. Endoscopic transsphenoidal surgery for pituitary adenoma resection is generally not associated with large dural defects and high-flow cerebrospinal fluid (CSF) leaks requiring extensive reconstruction. Here, we present the posterior nasoseptal flap as a novel technique for closure of skull defects following endoscopic resection of pituitary adenomas. This flap is raised in all surgeries during the transnasal exposure using septal mucoperiosteum that would otherwise be discarded during the posterior septectomy performed in binostril approaches. Methods: We present a retrospective, consecutive case series of 43 patients undergoing endoscopic transsphenoidal resection of a pituitary adenoma followed by posterior nasoseptal flap placement and closure. Main outcome measures were extent of resection and postoperative CSF leak. Results: The mean extent of resection was 97.16 ± 1.03%. Radiographic measurement showed flap length to be adequate. While a defect in the diaphragma sellae and CSF leak were identified in 21 patients during surgery, postoperative CSF leak occurred in only one patient. Conclusions: The posterior nasoseptal flap provides adequate coverage of the surgical defect and is nearly always successful in preventing postoperative CSF leak following endoscopic transsphenoidal resection of pituitary adenomas. The flap is raised from mucoperiosteum lining the posterior nasal septum, which is otherwise resected during posterior septectomy. Because the anterior septal cartilage is not denuded, raising such flaps avoids the postoperative morbidity associated with the larger Hadad-Bassagasteguy nasoseptal flap. PMID:29527390

Application of computational aeroacoustic methodologies to advanced propeller configurations - A review

NASA Technical Reports Server (NTRS)

Korkan, Kenneth D.; Eagleson, Lisa A.; Griffiths, Robert C.

1991-01-01

Current research in the area of advanced propeller configurations for performance and acoustics are briefly reviewed. Particular attention is given to the techniques of Lock and Theodorsen modified for use in the design of counterrotating propeller configurations; a numerical method known as SSTAGE, which is a Euler solver for the unducted fan concept; the NASPROP-E numerical analysis also based on a Euler solver and used to study the near acoustic fields for the SR series propfan configurations; and a counterrotating propeller test rig designed to obtain an experimental performance/acoustic data base for various propeller configurations.

Paramuscular perforators in DIEAP flap for breast reconstruction.

PubMed

Pons, Gemma; Masia, Jaume; Sanchez-Porro, Lídia; Larrañaga, Jose; Clavero, Juan Angel

2014-12-01

One of the main steps in perforator flap surgery is to identify the dominant perforator. Using multidetector row computed tomography (MDCT) for the preoperative planning of deep inferior epigastric artery perforator (DIEAP) flap surgery, we identified a perforator with a large caliber, an excellent location in the middle abdominal region, and a totally extramuscular trajectory in a significant number of patients. We describe the frequency of this perforator and determine its characteristics. We conducted a retrospective study of 482 patients who underwent 526 DIEAP flaps for breast reconstruction from October 2003 to October 2011. Mean age at surgery was 51.3 years old. A preoperative MDCT of abdominal vascularization was performed in all patients. MDCT identified a dominant perforator with a paramuscular course in 12.4% of abdominal walls. In all cases, it was located in the midline and emerged directly from the deep inferior epigastric system. Its mean caliber was 1.9 mm. The flap was harvested based on this perforator in all these patients, and mean harvest time was 51 minutes. The characteristics of this perforator made dissection easier and reduced morbidity at the donor site. There were no flap losses and the only complications were minor. We located a paramuscular perforator in 12.4% of patients undergoing breast reconstruction with abdominal perforator flaps. Its morphological features and extramuscular course make it the perforator of choice in DIEAP flap surgery.

Self-actuating and self-diagnosing plastically deforming piezo-composite flapping wing MAV

NASA Astrophysics Data System (ADS)

Harish, Ajay B.; Harursampath, Dineshkumar; Mahapatra, D. Roy

2011-04-01

In this work, we propose a constitutive model to describe the behavior of Piezoelectric Fiber Reinforced Composite (PFRC) material consisting of elasto-plastic matrix reinforced by strong elastic piezoelectric fibers. Computational efficiency is achieved using analytical solutions for elastic stifness matrix derived from Variational Asymptotic Methods (VAM). This is extended to provide Structural Health Monitoring (SHM) based on plasticity induced degradation of flapping frequency of PFRC. Overall this work provides an effective mathematical tool that can be used for structural self-health monitoring of plasticity induced flapping degradation of PFRC flapping wing MAVs. The developed tool can be re-calibrated to also provide SHM for other forms of failures like fatigue, matrix cracking etc.

In vivo preclinical verification of a multimodal diffuse reflectance and correlation spectroscopy system for sensing tissue perfusion

NASA Astrophysics Data System (ADS)

Pakela, Julia M.; Lee, Seung Yup; Hedrick, Taylor L.; Vishwanath, Karthik; Helton, Michael C.; Chung, Yooree G.; Kolodziejski, Noah J.; Staples, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Christian, James F.; O'Reilly, Jameson; Farkas, Dana; Ward, Brent B.; Feinberg, Stephen E.; Mycek, Mary-Ann

2017-02-01

In reconstructive surgery, impeded blood flow in microvascular free flaps due to a compromise in arterial or venous patency secondary to blood clots or vessel spasms can rapidly result in flap failures. Thus, the ability to detect changes in microvascular free flaps is critical. In this paper, we report progress on in vivo pre-clinical testing of a compact, multimodal, fiber-based diffuse correlation and reflectance spectroscopy system designed to quantitatively monitor tissue perfusion in a porcine model's surgically-grafted free flap. We also describe the device's sensitivity to incremental blood flow changes and discuss the prospects for continuous perfusion monitoring in future clinical translational studies.

Thermal Decomposition Behaviors and Burning Characteristics of AN/Nitramine-Based Composite Propellant

NASA Astrophysics Data System (ADS)

Naya, Tomoki; Kohga, Makoto

2015-04-01

Ammonium nitrate (AN) has attracted much attention due to its clean burning nature as an oxidizer. However, an AN-based composite propellant has the disadvantages of low burning rate and poor ignitability. In this study, we added nitramine of cyclotrimethylene trinitramine (RDX) or cyclotetramethylene tetranitramine (HMX) as a high-energy material to AN propellants to overcome these disadvantages. The thermal decomposition and burning rate characteristics of the prepared propellants were examined as the ratio of AN and nitramine was varied. In the thermal decomposition process, AN/RDX propellants showed unique mass loss peaks in the lower temperature range that were not observed for AN or RDX propellants alone. AN and RDX decomposed continuously as an almost single oxidizer in the AN/RDX propellant. In contrast, AN/HMX propellants exhibited thermal decomposition characteristics similar to those of AN and HMX, which decomposed almost separately in the thermal decomposition of the AN/HMX propellant. The ignitability was improved and the burning rate increased by the addition of nitramine for both AN/RDX and AN/HMX propellants. The increased burning rates of AN/RDX propellants were greater than those of AN/HMX. The difference in the thermal decomposition and burning characteristics was caused by the interaction between AN and RDX.

Human Fanconi Anemia Complementation Group A Protein Stimulates the 5’ Flap Endonuclease Activity of FEN1

PubMed Central

Qian, Liangyue; Yuan, Fenghua; Rodriguez-Tello, Paola; Padgaonkar, Suyog; Zhang, Yanbin

2013-01-01

In eukaryotic cells, Flap endonuclease 1 (FEN1) is a major structure-specific endonuclease that processes 5’ flapped structures during maturation of lagging strand DNA synthesis, long patch base excision repair, and rescue of stalled replication forks. Here we report that fanconi anemia complementation group A protein (FANCA), a protein that recognizes 5’ flap structures and is involved in DNA repair and maintenance of replication forks, constantly stimulates FEN1-mediated incision of both DNA and RNA flaps. Kinetic analyses indicate that FANCA stimulates FEN1 by increasing the turnover rate of FEN1 and altering its substrate affinity. More importantly, six pathogenic FANCA mutants are significantly less efficient than the wild-type at stimulating FEN1 endonuclease activity, implicating that regulation of FEN1 by FANCA contributes to the maintenance of genomic stability. PMID:24349332

Aerodynamic characteristics of a small-scale straight and swept-back wing with knee-blown jet flaps

NASA Technical Reports Server (NTRS)

Morehouse, G. G.; Eckert, W. T.; Boles, R. A.

1977-01-01

Two sting-mounted, 50.8 cm (20 in.) span, knee-blown, jet-flap models were tested in a large (2.1- by 2.5-m (7- by 10-ft) subsonic wind tunnel. A straight- and swept-wing model were tested with fixed flap deflection with various combinations of full-span leading-edge slats. The swept-wing model was also tested with wing tip extensions. Data were taken at angles-of-attack between 0 deg and 40 deg, at dynamic pressures between 143.6 N/sq m (3 lb/sq ft) and 239.4 N/sq m (5 lb/sq ft), and at Reynolds numbers (based on wing chord) ranging from 100,000 to 132,000. Jet flap momentum blowing coefficients up to 10 were used. Lift, drag, and pitching-moment coefficients, and exit flow profiles for the flap blowing are presented in graphical form without analysis.

Perturbation solutions for the influence of forward flight on helicopter rotor flapping stability

NASA Technical Reports Server (NTRS)

Johnson, W.

1974-01-01

The stability of the flapping motion of a helicopter rotor blade in forward flight is investigated, using a perturbation technique which gives analytic expressions for the eigenvalues, including the influence of the periodic aerodynamic forces in forward flight. The perturbation solutions are based on small advance ratio (the ratio of the helicopter forward speed to the rotor tip speed). The rotor configurations considered are a single, independent blade; a teetering rotor; a gimballed rotor with three, four, and five or more blades; and a rotor with N independent blades. The constant coefficient approximation with the equations and degrees of freedom in the nonrotating frame represents the flap dynamic reasonably well for the lower frequency modes, although it cannot, of course, be completely correct. The transfer function of the rotor flap response to sinusoidal pitch input is examined, as an alternative to the eigenvalues as a representation of the dynamic characteristics of the flap motion.

Enhancement of venous drainage with vein stripper for reversed pedicled neurocutaneous flaps.

PubMed

Sonmez, Erhan; Silistireli, Özlem Karataş; Karaaslan, Önder; Kamburoğlu, Haldun Onuralp; Safak, Tunc

2013-05-01

The flaps based on the vascular axis of superficial sensitive cutaneous nerves had gained increased popularity in reconstructive surgery because of such major advantages as preservation of major extremity arteries and avoidance of microsurgical procedures. However, postoperative venous congestion resulting in partial or total necrosis is still a common problem for these flaps. The aim of the current study is to introduce a new method for reducing the postoperative venous congestion of neural island flap with the results of reconstruction of the soft tissue defects of foot and ankle. This method was used to treat 19 patients with various chronic soft tissue defects of the foot and ankle between 2011 and 2012. We observed that the novel method presented in this report enables effective venous drainage, solving the postoperative venous congestion problem of these flaps. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Performance of Swashplateless Ultralight Helicopter Rotor with Trailing-edge Flaps for Primary Flight Control

NASA Technical Reports Server (NTRS)

Shen, Jin-Wei; Chopra, Inderjit

2003-01-01

The objective of present study is to evaluate the rotor performance, trailing-edge deflections and actuation requirement of a helicopter rotor with trailing-edge flap system for primary flight control. The swashplateless design is implemented by modifying a two-bladed teetering rotor of an production ultralight helicopter through the use of plain flaps on the blades, and by replacing the pitch link to fixed system control system assembly with a root spring. A comprehensive rotorcraft analysis based on UMARC is carried out to obtain the results for both the swashplateless and a conventional baseline rotor configuration. The predictions show swashplateless configuration achieve superior performance than the conventional rotor attributed from reduction of parasite drag by eliminating swashplate mechanic system. It is indicated that optimal selection of blade pitch index angle, flap location, length, and chord ratio reduces flap deflections and actuation requirements, however, has virtually no effect on rotor performance.

Dynamic interference of two anti-phase flapping foils in side-by-side arrangement in an incompressible flow

NASA Astrophysics Data System (ADS)

Bao, Y.; Zhou, D.; Tao, J. J.; Peng, Z.; Zhu, H. B.; Sun, Z. L.; Tong, H. L.

2017-03-01

A two-dimensional computational hydrodynamic model is developed to investigate the propulsive performance of a flapping foil system in viscous incompressible flows, which consists of two anti-phase flapping foils in side-by-side arrangement. In the simulations, the gap between the two foils is varied from 1.0 to 4.0 times of the diameter of the semi-circular leading edge; the amplitude-based Strouhal number is changed from 0.06 to 0.55. The simulations therefore cover the flow regimes from negligible to strong interference in the wake flow. The generations of drag and thrust are investigated as well. The numerical results reveal that the counter-phase flapping motion significantly changes the hydrodynamic force generation and associated propulsive wake. Furthermore, the wake interference becomes important for the case with a smaller foil-foil gap and induces the inverted Bénard von Kármán vortex streets. The results show that the hydrodynamic performance of two anti-phase flapping foils can be significantly different from an isolated pitching foil. Findings of this study are expected to provide new insight for developing hydrodynamic propulsive systems by improving the performance based on the foil-foil interaction.

Lead-Free Double-Base Propellant for the 2.75 Inch Rocket Motor

NASA Technical Reports Server (NTRS)

Magill, B. T.; Nauflett, G. W.; Furrow, K. W.

2000-01-01

The current MK 66 2.75 inch Rocket Motor double-base propellant contains the lead-based ballistic modifier LC-12-15 to achieve the desired plateau and mesa burning rate characteristics. The use of lead compounds poses a concern for the environment and for personal safety due to the metal's toxic nature when introduced into the atmosphere by propellant manufacture, rocket motor firing, and disposal. Copper beta-resorcylate (copper 2,4-di-hydroxy-benzoate) was successfully used in propellant as a simple modifier in the mid 1970's. This and other compounds have also been mixed with lead salts to obtain more beneficial ballistic results. Synthesized complexes of lead and copper compounds soon replaced the mixtures. The complexes incorporate the lead, copper lack of organic liquids, which allows for easier propellant processing. About ten years ago, the Indian Head Division, Naval Surface Warfare Center (NSWC), initiated an effort to develop a lead-free propellant for use in missile systems. Several lead-free propellant candidate formulations were developed. About five years ago, NSWC, in conjunction with Alliant Techsystems, Radford Army Ammunition Plant, continued ballistic modifier investigations. A four component ballistic modifier system without lead for double-base propellants that provide adequate plateau and mesa burn rate characteristics was developed and patented. The ballistic modifier's system contains bismuth subsalicylate, 1.5 percent; copper salicylate, 1.0 percent, copper stannate, 0.77 percent; and carbon black, 0.1 percent. Action time and impulse data obtained through multiple static firings indicate that the new lead-free double-base propellant, while not a match for NOSIH-AA-2, will be a very suitable replacement in the 2.75 inch Rocket Motor. Accelerated aging of the double-base propellant containing the lead-free ballistic modifier showed that it had a much higher rate of stabilizer depletion than the AA-2. A comprehensive study showed that an increased rate of stabilizer depletion occurred in propellants containing monobasic copper salicylate. The study also showed that propellants containing a mixture of bismuth subsalicylate and copper salicylate, had only about one-half the stabilizer depletion rate than those with copper salicylate alone. The copper salicylate catalyzes the decomposition of nitroglycerin, which triggers a chain of events leading to the increased rate of stabilizer depletion. A program has been initiated to coat the ballistic modifier, thus isolating it from the nitroglycerin.

The figure-of-eight radix nasi flap for medial canthal defects.

PubMed

Seyhan, Tamer

2010-09-01

Basal cell carcinomas commonly involve the medial canthal region and reconstruction of medial canthal defects is a challenging problem in reconstructive surgery. A new axial pattern flap raised from radix nasi region has been successfully used for the medial canthal defects in eight patients in figure-of-eight manner. One of the ellipses of the figure of eight is the defect, the other is the radix nasi flap. The radix nasi flap with a dimension up to 25 mm is transposed to the defect based either on ipsilateral anastomosis of the dorsal nasal artery with angular artery (AA) or with the connection of its source artery (i.e. ophthalmic artery) if the AA is damaged. All flaps survived and no tumour recurrence was observed. The donor sites were closed primarily and hidden at the radix nasi crease in all cases. The radix nasi flap in figure-of-eight fashion is good alternative for defects of the medial canthal area in terms of attaining a suitable colour and texture and minimal surgical scars. Copyright 2009 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Inertia may limit efficiency of slow flapping flight, but mayflies show a strategy for reducing the power requirements of loiter.

PubMed

Usherwood, James R

2009-03-01

Predictions from aerodynamic theory often match biological observations very poorly. Many insects and several bird species habitually hover, frequently flying at low advance ratios. Taking helicopter-based aerodynamic theory, wings functioning predominantly for hovering, even for quite small insects, should operate at low angles of attack. However, insect wings operate at very high angles of attack during hovering; reduction in angle of attack should result in considerable energetic savings. Here, I consider the possibility that selection of kinematics is constrained from being aerodynamically optimal due to the inertial power requirements of flapping. Potential increases in aerodynamic efficiency with lower angles of attack during hovering may be outweighed by increases in inertial power due to the associated increases in flapping frequency. For simple hovering, traditional rotary-winged helicopter-like micro air vehicles would be more efficient than their flapping biomimetic counterparts. However, flapping may confer advantages in terms of top speed and manoeuvrability. If flapping-winged micro air vehicles are required to hover or loiter more efficiently, dragonflies and mayflies suggest biomimetic solutions.

Aerothermal Assment Of The Expert Flap In The SCIROCCO Wind Tunnel

NASA Astrophysics Data System (ADS)

Walpot, L.; Di Clemente, M.; Vos, J.; Etchells, J.; Trifoni, E.; Thoemel, J.; Gavira, J.

2011-05-01

In the frame of the “In-Flight Test Measurement Techniques for Aerothermodynamics” activity of the EXPERT Program, the EXPERT Instrumented Open Flap Assembly experiment has the objective to verify the design/sensor integration and validate the CFD tools. Ground based measurements were made in Europe’s largest high enthalpy plasma facility, Scirocco in Italy. Two EXPERT flaps of the flight article, instrumented with 14 thermocouples, 5 pressure ports, a pyrometer and an IR camera mounted in the cavity instrumented flap will collect in-flight data. During the Scirocco experiment, an EXPERT flap model identical to the flight article was mounted at 45 deg on a holder including cavity and was subjected to a hot plasma flow at an enthalpy up to 11MJ/kg at a stagnation pressure of 7 bar. The test model sports the same pressure sensors as the flight article. Hypersonic state-of-the-art codes were then be used to perform code-to-code and wind tunnel-to-code comparisons, including thermal response of the flap as collected during the tests by the sensors and camera.

Treatment of Implant Exposure due to Skin Necroses after Skin Sparing Mastectomy: Initial Experiences Using a Not Selective Random Epigastric Flap.

PubMed

Echazarreta-Gallego, Estíbaliz; Pola-Bandrés, Guillermo; Arribas-Del Amo, María Dolores; Gil-Romea, Ismael; Sousa-Domínguez, Ramón; Güemes-Sánchez, Antonio

2017-10-01

Breast prostheses exposure is probably the most devastating complication after a skin sparing mastectomy (SSM) and implant-based, one-stage, breast reconstruction. This complication may occur in the immediate post-operative period or in the weeks and even months after the procedure. In most cases, the cause is poor skin coverage of the implant due to skin necrosis. Eight consecutive cases of implant exposure (or risk of exposure) due to skin necrosis in SSM patients over a period of 5 years, all patients were treated using a random epigastric rotation flap, executed by the same medical team. A random epigastric flap (island or conventional rotation flap) was used to cover the skin defect. All the patients completed the procedure and all prostheses were saved; there were no cases of flap necrosis or infection. Cases of skin necrosis after SSM and immediate implant reconstruction, in which the implant is at risk of exposure, can be successfully treated with a random epigastric rotation flap.

[Effects and related mechanism of bivalirudin on the survival of random skin flap on the back of rat].

PubMed

Cai, L Y; Wang, T; Lin, D S; Lu, D

2017-04-20

Objective: To investigate the effects and related mechanism of bivalirudin on the survival of random skin flap on the back of rat. Methods: Thirty SD rats were divided into bivalirudin group and normal saline group according to the random number table, with 15 rats in each group. The random flap model with size of 9 cm×3 cm was reproduced on the back of rats in two groups. Immediately post injury, rats in bivalirudin group were intraperitoneally injected with 5 mg/mL bivalirudin (0.8 mL/kg), while rats in normal saline group were intraperitoneally injected with normal saline (0.8 mL/kg) once a day. The continuous injection lasted for 7 days. The flap was divided into distal area, middle area and proximal area averagely based on the flap blood supply. On post injury day (PID) 1, 3, and 7, the overall survival of each area of flap was observed with naked eyes. On PID 7, the survival rate of flap was calculated, and then the morphology of skin tissue at the center of the three areas of flap was observed by HE staining, the microvessel density (MVD) of the middle area of flap was calculated, and the expression of vascular endothelial growth factor (VEGF) of the middle area of flap was detected with immunohistochemical staining. Data were processed with t test. Results: (1) On PID 1, flaps of rats in two groups had different degrees of swelling, mainly concentrated in distal area, but there was no obvious necrosis. The middle area and proximal area of flaps in two groups were survived. On PID 3, the necrosis of flaps of rats in two groups was concentrated in the middle area, while the proximal area of flap was still in survival state, and most distal area of flap was necrosis with a little scab. On PID 7, the necrosis of middle area of flaps of rats in two groups was gradually fused, and the survival area of flap of rats in bivalirudin group was larger than that in normal saline group. The distal area of flap was almost necrotic, and the proximal area of flap was almost survived. (2) On PID 7, the survival rate of flap of rats in bivalirudin group was (64±4)%, significantly higher than that in normal saline group [(45±3)%, t =13.49, P <0.01]. (3) On PID 7, the histological morphology of distal area of flap of rats in two groups was similar, the inflammatory cells were infiltrated abundantly, and tissue edema was obvious. A large number of new blood vessels appeared in the middle area of flap of rats in bivalirudin group, with the formation of collateral vessels, and basic dilation of new blood vessels was seen. There were fewer new blood vessels appeared in the middle area of flap of rats in normal saline group, and dilation of new blood vessels was not obvious. There was little inflammatory cells infiltration in the proximal area of flap of rats in two groups. Compared with that in normal saline group, tissue edema extent of proximal area of flap of rats in bivalirudin group was less, and expansion was observed in more blood vessels. (4) The MVD of middle area of flap of rats in bivalirudin group was (26±5)/mm(2,) significantly higher than that in normal saline group [(18±3)/mm(2,) t =5.43, P <0.05]. (5) The expression of VEGF of middle area of flap of rats in bivalirudin group was 6 534±384, significantly higher than that in normal saline group (4 659±448, t =12.31, P <0.05). Conclusions: Bivalirudin can promote the survival of random skin flap in rats, and the mechanisms may include reducing the formation of thrombosis, improving the blood supply of flap, and increasing the expression of VEGF, promoting the formation of new blood vessels.

A new agent for flap survival – Hippophae rhamnoides L. (sea buckthorn): An experimental study in rats

PubMed Central

Emsen, Ilteris Murat

2005-01-01

Hippophae rhamnoides L. (sea buckthorn) is a member of the Elaeagnaceae family, and is a temperate bush native to Europe and Asia. The antioxidant activity of H rhamnoides L. has been shown in vitro cell culture and animal studies. Different fractions of H rhamnoides L. fruits inhibit 2,2-azobis-(2,4 dimethylvaleronitrile) and ascorbate iron-induced lipid peroxidations in vitro. H rhamnoides L., as well as vitamin E, decrease the malondialdehyde content in hyperlipidemic rabbit serum-cultured smooth muscle cells. The aim of the present study was to investigate, in a rat model, the potential effect of H rhamnoides L. on survival of random pattern skin flaps. For this purpose, 30 Wistar Albino rats were used, and a McFarlane-type caudally based skin flap was created on the dorsum of the rat (2.5 cm × 8 cm). Rats were divided into three groups: one control (group A) and two treatment groups (groups B and C). H rhamnoides L. was administered orally to the experimental groups: group B received a single 15 mg/kg dose per day and group C received 15 mg/kg twice per day. The areas and lengths of flap necrosis were measured in each group. The extent of necrotic flap areas were evaluated as length and area of total flap area, and differences were studied by Student’s t tests. The areas and lengths of necrosis of skin flaps decreased depending on H rhamnoides L., but viability of the flaps treated with 15 mg/kg/day was not significantly different from the control group. The rats receiving H rhamnoides L. 15 mg/kg twice per day had the highest flap survival rate (P<0.001). In conclusion, H rhamnoides L. may have a dose-dependent effect to increase flap survival in random skin flaps. PMID:24227931

The pedicled internal pudendal artery perforator (PIPAP) flap for ischial pressure sore reconstruction: Technique and long-term outcome of a cohort study.

PubMed

Legemate, Catherine M; van der Kwaak, Monique; Gobets, David; Huikeshoven, Menno; van Zuijlen, Paul P M

2018-06-01

The ischial region is the site most affected by pressure sores and has the highest recurrence and complication rates compared to other affected sites. We developed a practical and safe pedicled flap for reconstruction of ischial pressure sores based on the rich available perforators from the internal pudendal artery and the surplus of skin at the infragluteal fold. A retrospective cohort study was conducted in all patients who underwent ischial pressure ulcer reconstruction using the PIPAP flap between March 2010 and March 2017. The skin flap was designed along the gluteal fold. The skin perforators of the pudendal artery were marked with a Doppler probe in the medial region of the gluteal fold. Surgery was performed in the jackknife position, and flaps were elevated in the suprafascial plane. Patients were assessed for minor (requiring no additional surgery) and major complications (requiring additional surgery). Twenty-seven patients (34 flaps) were identified. The median follow-up period was 38 months (IQR 37). Primary closure of the donor-site was achieved in all procedures, only one flap required muscle flap transposition in order to fill the dead space. The mean operating time was 60 ± 21 minutes. In six flaps (9%) wound healing problems were noted that did not require an additional operative procedure. Among the nine flaps (27%) that required a second procedure, 3 (9%) were necessary due to recurrent ulcers. The PIPAP flap is a safe and reliable alternative for ischial pressure sore reconstruction, certainly when compared to available techniques. Moreover, it has significant advantages over other techniques including minimal donor-site morbidity, preservation of posterior thigh skin, buttock-line integrity and reliable vascularity. Copyright © 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

The Deep Inferior Epigastric Perforator and Pedicled Transverse Rectus Abdominis Myocutaneous Flap in Breast Reconstruction: A Comparative Study

PubMed Central

Tan, Shane; Yek, Jacklyn; Ong, Wei Chen; Hing, Chor Hoong; Lim, Thiam Chye

2013-01-01

Background Our objective was to compare the complication rates of two common breast reconstruction techniques performed at our hospital and the cost-effectiveness for each test group. Methods All patients who underwent deep inferior epigastric perforator (DIEP) flap and transverse rectus abdominis myocutaneous (TRAM) flap by the same surgeon were selected and matched according to age and mastectomy with or without axillary clearance. Patients from each resultant group were selected, with the patients matched chronologically. The remainder were matched for by co-morbidities. Sixteen patients who underwent immediate breast reconstruction with pedicled TRAM flaps and 16 patients with DIEP flaps from 1999 to 2006 were accrued. The average total hospitalisation cost, length of hospitalisation, and complications in the 2 year duration after surgery for each group were compared. Results Complications arising from both the pedicled TRAM flaps and DIEP flaps included fat necrosis (TRAM, 3/16; DIEP, 4/16) and other minor complications (TRAM, 3/16; DIEP, 1/16). The mean hospital stay was 7.13 days (range, 4 to 12 days) for the pedicled TRAM group and 7.56 (range, 5 to 10 days) for the DIEP group. Neither the difference in complication rates nor in hospital stay duration were statistically significant. The total hospitalisation cost for the DIEP group was significantly higher than that of the pedicled TRAM group (P<0.001). Conclusions Based on our study, the pedicled TRAM flap remains a cost-effective technique in breast reconstruction when compared to the newer, more expensive and tedious DIEP flap. PMID:23730591

HSCT Ref-H Transonic Flap Data Base: Wind-Tunnel Test and Comparison with Theory

NASA Technical Reports Server (NTRS)

Vijgen, Paul M.

1999-01-01

In cooperation with personnel from the Boeing ANP Laboratory and NASA Langley, a performance test was conducted using the Reference-H 1.675% model ("NASA Modular Model") without nacelles at the NASA Langley 16-Ft Transonic Tunnel. The main objective of the test was to determine the drag reduction achievable with leading-edge and trailing-edge flaps deflected along the outboard wing span at transonic Mach numbers (M = 0.9 to 1.2) for purpose of preliminary design and for comparison with computational predictions. The obtained drag data with flap deflections for Mach numbers of 1.07 to 1.20 are unique for the Reference H wing. Four leading-edge and two trailing-edge flap deflection angles were tested at a mean-wing chord-Reynolds number of about 5.7 million. An outboard-wing leading-edge flap deflection of 81 provides a 4.5 percent drag reduction at M = 1.2 A = 0.2), and much larger values at lower Mach numbers with larger flap deflections. The present results for the baseline (no flaps deflected) compare reasonably well with previous Boeing and NASA Ref-H tunnel tests, including high-Reynolds number NTF results. Viscous CFD simulations using the OVERFLOW thin-layer N.S. method properly predict the observed trend in drag reduction at M = 1.2 as function of leading-edge flap deflection. Modified linear theory properly predicts the flap effects on drag at subsonic conditions (Aero2S code), and properly predicts the absolute drag for the 40 and 80 leading-edge deflection at M = 1.2 (A389 code).

Characteristics of merging shear layers and turbulent wakes of a multi-element airfoil

NASA Technical Reports Server (NTRS)

Adair, Desmond; Horne, W. Clifton

1988-01-01

Flow characteristics in the vicinity of the trailing edge of a single-slotted airfoil flap are presented and analyzed. The experimental arrangement consisted of a NACA 4412 airfoil equipped with a NACA 4415 flap whose angle of deflection was 21.8 deg. The flow remained attached over the model surfaces except in the vicinity of the flap trailing edge where a small region of boundary-layer separation extended over the aft 7 percent of flap chord. The flow was complicated by the presence of a strong, initially inviscid jet emanating from the slot between airfoil and flap, and a gradual merging of the main airfoil wake and flap suction-side boundary layer. Downstream of the flap, the airfoil and flap wakes fully merged to form an asymmetrical curved wake. The airfoil configuration was tested at an angle of attack of 8.2 deg, at a Mach number of 0.09, and a chord based Reynolds number of 1.8 x 10 to the 6th power in the Ames Research Center 7- by 10-Foot Wind Tunnel. Surface pressure measurements were made on the airfoil and flap and on the wind tunnel roof and floor. It was estimated that the wall interference increased the C sub L by 7 percent and decreased the C sub M by 4.5 percent. Velocity characteristics were quantified using hot-wire anemometry in regions of flow with preferred direction and low turbulence intensity. A 3-D laser velocimeter was used in regions of flow recirculation and relatively high turbulence intensity.

A Novel Free Flap Monitoring System Using Tissue Oximetry with Text Message Alerts.

PubMed

Ricci, Joseph A; Vargas, Christina R; Lin, Samuel J; Tobias, Adam M; Taghinia, Amir H; Lee, Bernard T

2016-06-01

Background The time to detection of vascular compromise is a significant predictor of free flap salvage outcomes as early reexploration improves salvage rates. Continuous transcutaneous near-infrared tissue oximetry is an objective, quantitative method of detecting flap vascular compromise and has been shown to allow earlier reexploration and higher salvage rates than clinical assessment alone. We designed a novel text messaging system to improve communication using tissue oximetry monitoring. Methods A retrospective review was performed of a prospectively collected database of all microsurgical breast reconstructions from 2008 to 2015. A novel text messaging system was introduced in 2013 and programmed to send text messages alert when the tissue oximetry readings suggested potential flap compromise based on established thresholds. Patient demographics and complications, including rate of reexploration and flap loss were assessed. Results There were 900 autologous microsurgical breast free flaps during the study period: 614 were monitored with standard clinical monitoring and tissue oximetry compared with 286 flaps with the additional text messaging system. There were 27 unplanned returns to the operating room in the tissue oximetry group and 5 in the text messaging group with 1 complete flap loss in each group. Reexploration occurred sooner as a result of these text message alerts (17.5 vs. 26.6 hours postoperatively), however, it did not achieve statistical significance. Conclusions We were able to demonstrate the use of a novel text messaging system for tissue oximetry. This alert system shows promise in identifying impending flap loss with rapid notification of the surgical team. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Fabrication of Graded Porous and Skin-Core Structure RDX-Based Propellants via Supercritical CO2 Concentration Profile

NASA Astrophysics Data System (ADS)

Yang, Weitao; Li, Yuxiang; Ying, Sanjiu

2015-04-01

A fabrication process to produce graded porous and skin-core structure propellants via supercritical CO2 concentration profile is reported in this article. It utilizes a partial gas saturation technique to obtain nonequilibrium gas concentration profiles in propellants. Once foamed, the propellant obtains a graded porous or skin-pore structure. This fabrication method was studied with RDX(Hexogen)-based propellant under an SC-CO2 saturation condition. The principle was analyzed and the one-dimensional diffusion model was employed to estimate the gas diffusion coefficient and to predict the gas concentration profiles inside the propellant. Scanning electron microscopy images were used to analyze the effects of partial saturation on the inner structure. The results also suggested that the sorption time and desorption time played an important role in gas profile generation and controlled the inner structure of propellants.

14 CFR 35.38 - Lightning strike.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by tests, analysis based on tests, or experience on similar designs, that the propeller can withstand a lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller has...

14 CFR 35.38 - Lightning strike.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by tests, analysis based on tests, or experience on similar designs, that the propeller can withstand a lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller has...

14 CFR 35.38 - Lightning strike.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by tests, analysis based on tests, or experience on similar designs, that the propeller can withstand a lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller has...

14 CFR 35.38 - Lightning strike.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by tests, analysis based on tests, or experience on similar designs, that the propeller can withstand a lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller has...

14 CFR 35.38 - Lightning strike.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by tests, analysis based on tests, or experience on similar designs, that the propeller can withstand a lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller has...

The endonasal endoscopic harvest and anatomy of the buccal fat pad flap for closure of skull base defects.

PubMed

Markey, Jeff; Benet, Arnau; El-Sayed, Ivan H

2015-10-01

Extirpation via expanded endonasal approaches (EEA) to the skull base can result in defects requiring vascularized rotational flap reconstruction. The buccal fat pad (BFP) is a vascularized graft described in open skull base resections, but its harvest and adequacy of vascular supply have not been examined for use with EEA. A transfacial cadaveric dissection was carried forth in a latex-injected specimen to characterize the BFP blood supply. Then a cadaveric dissection series was performed involving the endoscopic harvest and rotation of 10 buccal fat pads in five cadaveric specimens to assess defect coverage. An endoscopic medial maxillectomy combined with an anterior maxillotomy was performed prior to endoscopic harvest in cadaveric specimens. The BFP was rotated to assess its capability to reconstruct seven possible ventral skull base defects. Finally, the BFP vascular anatomy was further characterized following harvest and transposition. The BFP reconstructed defects at the greater sphenoid wing, inferior and superior clivus, sella, planum, and bilateral ethmoids in all cadaveric specimens. In some cases it covered two sites concurrently. The BFP pedicled rotational flap is a potential alternate flap following EEA in select cases. NA © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

On the combustion mechanisms of ZrH2 in double-base propellant.

PubMed

Yang, Yanjing; Zhao, Fengqi; Yuan, Zhifeng; Wang, Ying; An, Ting; Chen, Xueli; Xuan, Chunlei; Zhang, Jiankan

2017-12-13

Metal hydrides are regarded as a series of promising hydrogen-supplying fuel for solid rocket propellants. Their effects on the energetic and combustion performances of propellants are closely related to their reaction mechanisms. Here we report a first attempt to determine the reaction mechanism of ZrH 2 , a high-density metal hydride, in the combustion of a double-base propellant to evaluate its potential as a fuel. ZrH 2 is determined to possess good resistance to oxidation by nitrocellulose and nitroglycerine. Thus its combustion starts with dehydrogenation to generate H 2 and metallic Zr. Subsequently, the newly formed Zr and H 2 participate in the combustion and, especially, Zr melts and then combusts on the burning surface which favors the heat feedback to the propellant. This phenomenon is completely different from the combustion behavior of the traditional fuel Al, where the Al particles are ejected off the burning surface of the propellant to get into the luminous flame zone to burn. The findings in this work validate the potential of ZrH 2 as a hydrogen-supplying fuel for double-base propellants.

Microsurgical reconstruction of the maxilla: Algorithm and concepts.

PubMed

Costa, Horácio; Zenha, Horácio; Sequeira, Hugo; Coelho, Gustavo; Gomes, Nuno; Pinto, Cristina; Martins, João; Santos, Diana; Andresen, Carolina

2015-05-01

The main purpose of this article is to highlight free tissue transfers as the first-choice method for three-dimensional (3D) maxillary reconstruction, particularly in providing enough bone for palate and maxillary arch reconstruction and consequently an implant-retained prosthesis. To achieve this, the myosseous free iliac crest was selected whenever possible as the first choice inside the reconstructive algorithm and free flap armamentarium. A new maxillectomy classification and algorithm reconstruction are proposed. Technical modifications and improvements accomplished over time are discussed, considering palate, dental implants and prosthesis, nasal sidewall, cranial base and dura, as well as recipient vessels. We present functional and aesthetic outcomes of the senior author's past 24-year experience (H. C.) with complex midface reconstructions. The authors report and analyse a 24-year experience with 57 midface defects in 54 patients (30 males and 24 females). A total of 57 maxillary defects - classified as Class I (limited maxillectomy) = 12, Class II (subtotal maxillectomy) = 15, Class III (total maxillectomy) = 19 and Class IV (orbitomaxillectomy) = 11 - were analysed regarding sex, age, tumour recurrence, free flap, reconstruction and necrosis. In addition, functional outcomes were evaluated regarding diet, speech, globe position and vision, while aesthetic outcomes were evaluated by patient and surgeon scores. A total of 52 free flaps were performed in 47 patients; three patients were operated upon twice; and two other patients needed two sequentially linked flow-through flaps. The free flap survival was 96% with two total flap losses (4%). The other seven patients were fitted with a soft tissue-retained obturator prosthesis. Microsurgical vascularised osteomyocutaneous free flaps are actually the gold standard for reconstruction of complex defects following maxillectomy. This algorithm is based on the anatomofunctional defect of the maxilla and it facilitates flap selection, which is a must. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Propeller torque load and propeller shaft torque response correlation during ice-propeller interaction

NASA Astrophysics Data System (ADS)

Polić, Dražen; Ehlers, Sören; Æsøy, Vilmar

2017-03-01

Ships use propulsion machinery systems to create directional thrust. Sailing in ice-covered waters involves the breaking of ice pieces and their submergence as the ship hull advances. Sometimes, submerged ice pieces interact with the propeller and cause irregular fluctuations of the torque load. As a result, the propeller and engine dynamics become imbalanced, and energy propagates through the propulsion machinery system until equilibrium is reached. In such imbalanced situations, the measured propeller shaft torque response is not equal to the propeller torque. Therefore, in this work, the overall system response is simulated under the ice-related torque load using the Bond graph model. The energy difference between the propeller and propeller shaft is estimated and related to their corresponding mechanical energy. Additionally, the mechanical energy is distributed among modes. Based on the distribution, kinetic and potential energy are important for the correlation between propeller torque and propeller shaft response.

Nasolabial Perforator Flap for One-stage Reconstruction of Nasal Defects

PubMed Central

Prakash, Siddharth; Panda, Ritesh; Kumar, Vivek; Saha, Shiv Shankar; Choudhary, Lalit; Pandey, Anurag; Reddy, J. Sasidhar

2017-01-01

Background: The excellent freedom of movement and range of this flap when based on a the nasolabial perforator flap have not been sufficiently explored. In this study, along with demonstrating the other key advantages of this flap over its traditional counterpart, we will endeavour to fill these lacunae in the available literature. Materials and Methods: From February 2009 to February 2012, twenty patients with nasal defects were repaired with a nasolabial perforator flap in the Department of Plastic and Cosmetic Surgery at Sir Ganga Ram Hospital, New Delhi. Of these, two patients (10%) underwent the procedure bilaterally. Thus, a total of 22 nasolabial perforator flap procedures were carried out. Prospectively, collected clinical records and data of each patient were retrospectively retrieved and reviewed to study the nasal defect and surgery done. Results: All the twenty (100%) patients had good functional and aesthetic outcome. All patients who had nasal stenosis preoperatively had very good improvement in the patency of the nasal passages, breathing and nasal blockage with complete recovery of symptoms. The patients were entirely satisfied with the functional recovery. Conclusions: The reliability and versatility of the nasolabial perforator flap exceed its recognised application in reconstruction of nasal defects and it must form a part of every plastic surgeon's armamentarium. PMID:28529417

The Lateral Proximal Phalanx Flap for Contractures and Soft Tissue Defects in the Proximal Interphalangeal Joint

PubMed Central

Beltrán, Aldo G.; Romero, Camilo J.

2016-01-01

Background: The management of contractures and soft tissue defects in the proximal interphalangeal (PIP) finger joint remains a challenge. We report a transposition flap from the lateral skin of the proximal phalanx that is based on perforating branches of the digital arteries and can be used safely for both palmar and dorsal cover defects. Methods: We first completed an anatomic study, dissecting 20 fingers in fresh cadavers with arterial injections and made the new flap in patients with dorsal or palmar defects in PIP joints. Results: In cadavers, we can reveal 4 constant branches from each digital artery in the proximal phalanx, with the more distal just in the PIP joint constituting the flap pedicle. Between February 2010 and February 2015, we designed 33 flaps in 29 patients, 7 for dorsal and 26 for palmar defects, with no instances of flap necrosis and 4 distal epidermolysis. The patients were between 4 and 69 years with no major complications, and all of the skin defects in the PIP joint were resolved satisfactorily without any relevant sequelae at the donor site. Conclusions: This flap procedure is an easy, reliable, versatile, and safe technique, and could be an important tool for the management of difficult skin defects and contractures at the PIP joint level. PMID:28082850

Axial propulsion with flapping and rotating wings, a comparison of potential efficiency.

PubMed

Kroninger, Christopher M

2018-04-18

Interest in biological locomotion and what advantages the principles governing it might offer in the design of manmade vehicles prompts one to consider the power requirements of flapping relative to rotary propulsion. The amount of work performed on the fluid surrounding a thrusting surface (wing or blade) is reflected in the kinetic energy of the wake. Consideration of the energy in the wake is sufficient to define absolute minimum limitations on the power requirement to generate a particular thrust. This work applies wake solutions to compare the minimum inviscid propulsive power requirement of wings flapping and in rotation at wing loading conditions reflective of hover through a state of lightly-loaded cruise. It is demonstrated that hovering flapping flight is less efficient than rotary wing propulsion except for the most extreme flap amplitude strokes ([Formula: see text]   >  160°) if operating at large wake wavelength. In cruise, a larger range of flap amplitude kinematics ([Formula: see text]  >  140°) can be aerodynamically more energy efficient for wake wavelengths reflective of biological propulsion. These results imply, based on the observed wing kinematics of continuous steady flight, that flapping propulsion in animals is unlikely to be more efficient than rotary propulsion.

Vertical ridge augmentation using xenogenous bone blocks: a comparison between the flap and tunneling procedures.

PubMed

Xuan, Feng; Lee, Chun-Ui; Son, Jeong-Seog; Fang, Yiqin; Jeong, Seung-Mi; Choi, Byung-Ho

2014-09-01

Previous studies have shown that the subperiosteal tunneling procedure in vertical ridge augmentation accelerates healing after grafting and prevents graft exposure, with minor postoperative complications. It is conceivable that new bone formation would be greater with the tunneling procedure than with the flap procedure, because the former is minimally invasive. This hypothesis was tested in this study by comparing new bone formation between the flap and tunneling procedures after vertical ridge augmentation using xenogenous bone blocks in a canine mandible model. Two Bio-Oss blocks were placed on the edentulous ridge in each side of the mandibles of 6 mongrel dogs. The blocks in each side were randomly assigned to grafting with a flap procedure (flap group) or grafting with a tunneling procedure (tunneling group). The mean percentage of newly formed bone within the block was 15.3 ± 6.6% in the flap group and 46.6 ± 23.4% in the tunneling group. Based on data presented in this study, when a tunneling procedure is used to place xenogenous bone blocks for vertical ridge augmentation, bone formation in the graft sites is significantly greater than when a flap procedure is used. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Blade-mounted trailing edge flap control for BVI noise reduction

NASA Technical Reports Server (NTRS)

Hassan, A. A.; Charles, B. D.; Tadghighi, H.; Sankar, L. N.

1992-01-01

Numerical procedures based on the 2-D and 3-D full potential equations and the 2-D Navier-Stokes equations were developed to study the effects of leading and trailing edge flap motions on the aerodynamics of parallel airfoil-vortex interactions and on the aerodynamics and acoustics of the more general self-generated rotor blade vortex interactions (BVI). For subcritical interactions, the 2-D results indicate that the trailing edge flap can be used to alleviate the impulsive loads experienced by the airfoil. For supercritical interactions, the results show the necessity of using a leading edge flap, rather than a trailing edge flap, to alleviate the interaction. Results for various time dependent flap motions and their effect on the predicted temporal sectional loads, differential pressures, and the free vortex trajectories are presented. For the OLS model rotor, contours of a BVI noise metric were used to quantify the effects of the trailing edge flap on the size and directivity of the high/low intensity noise region(s). Average reductions in the BVI noise levels on the order of 5 dB with moderate power penalties on the order of 18 pct. for a four bladed rotor and 58 pct. for a two bladed rotor were obtained.

14 CFR 35.42 - Components of the propeller control system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Components of the propeller control system... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.42 Components of the propeller control system. The applicant must demonstrate by tests, analysis based on tests, or service...

14 CFR 35.42 - Components of the propeller control system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Components of the propeller control system... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.42 Components of the propeller control system. The applicant must demonstrate by tests, analysis based on tests, or service...

14 CFR 35.42 - Components of the propeller control system.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Components of the propeller control system... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.42 Components of the propeller control system. The applicant must demonstrate by tests, analysis based on tests, or service...

14 CFR 35.42 - Components of the propeller control system.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Components of the propeller control system... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.42 Components of the propeller control system. The applicant must demonstrate by tests, analysis based on tests, or service...

14 CFR 35.42 - Components of the propeller control system.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Components of the propeller control system... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.42 Components of the propeller control system. The applicant must demonstrate by tests, analysis based on tests, or service...

14 CFR 21.6 - Manufacture of new aircraft, aircraft engines, and propellers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... engines, and propellers. 21.6 Section 21.6 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Manufacture of new aircraft, aircraft engines, and propellers. (a) Except as specified in paragraphs (b) and (c) of this section, no person may manufacture a new aircraft, aircraft engine, or propeller based on...

14 CFR 21.6 - Manufacture of new aircraft, aircraft engines, and propellers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... engines, and propellers. 21.6 Section 21.6 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Manufacture of new aircraft, aircraft engines, and propellers. (a) Except as specified in paragraphs (b) and (c) of this section, no person may manufacture a new aircraft, aircraft engine, or propeller based on...

14 CFR 21.6 - Manufacture of new aircraft, aircraft engines, and propellers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engines, and propellers. 21.6 Section 21.6 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Manufacture of new aircraft, aircraft engines, and propellers. (a) Except as specified in paragraphs (b) and (c) of this section, no person may manufacture a new aircraft, aircraft engine, or propeller based on...

14 CFR 21.6 - Manufacture of new aircraft, aircraft engines, and propellers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... engines, and propellers. 21.6 Section 21.6 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Manufacture of new aircraft, aircraft engines, and propellers. (a) Except as specified in paragraphs (b) and (c) of this section, no person may manufacture a new aircraft, aircraft engine, or propeller based on...

Acoustic analysis of the propfan

NASA Technical Reports Server (NTRS)

Farassat, F.; Succi, G. P.

1979-01-01

A review of propeller noise prediction technology is presented. Two methods for the prediction of the noise from conventional and advanced propellers in forward flight are described. These methods are based on different time domain formulations. Brief descriptions of the computer algorithms based on these formulations are given. The output of the programs (the acoustic pressure signature) was Fourier analyzed to get the acoustic pressure spectrum. The main difference between the two programs is that one can handle propellers with supersonic tip speed while the other is for subsonic tip speed propellers. Comparisons of the calculated and measured acoustic data for a conventional and an advanced propeller show good agreement in general.

Tailoring through Technology: A Retrospective Review of a Single Surgeon's Experience with Implant-Based Breast Reconstruction before and after Implementation of Laser-Assisted Indocyanine Green Angiography.

PubMed

Harless, Christin A; Jacobson, Steven R

2016-05-01

Reported complication rates of implant-based breast reconstruction in the literature exceed 50%, with mastectomy skin flap necrosis reported to occur in up to 25% of cases. Laser-assisted indocyanine green angiography (LA-ICGA) technology allows the surgeon to optimize preservation of the mastectomy skin flap while avoiding skin necrosis. The purpose of this study was to determine if outcomes of breast reconstruction are beneficially affected by using LA-ICGA. A total 269 consecutive women (467 breast reconstructions) undergoing implant-based breast reconstruction from 2008 to 2013 were examined. The complication rates of those who underwent reconstruction prior to the implementation of LA-ICGA were compared with those who were reconstructed after implementation of LA-ICGA. A total of 254 consecutive breast reconstructions were performed prior to implementation of LA-ICGA, and 213 breasts were reconstructed with the use of LA-ICGA. After implementation of LA-ICGA System, the rate of mastectomy skin flap necrosis decreased by 86% (6.7% versus 0.9%, p = 0.02). The overall complication rate prior to LA-ICGA was 13.8% compared with 6.6% with the use of LA-ICGA (p = 0.01). After LA-ICGA was incorporated, the percentage of patients undergoing single-stage reconstruction increased from 12% to 32% (p = <0.001). Implementation of LA-ICGA provides the surgeon with an objective assessment of mastectomy flap perfusion resulting in a trend toward overall reduction in complications as well as an 86% decrease in the rate of subsequent skin necrosis. The objective assessment of mastectomy flap perfusion allows the surgeon to tailor breast reconstruction intraoperatively, in real-time, adjusting for the individual patient's mastectomy flap perfusion. © 2016 Wiley Periodicals, Inc.

Utility of bleb imaging with anterior segment optical coherence tomography in clinical decision-making after trabeculectomy.

PubMed

Singh, Mandeep; Aung, Tin; Aquino, Maria C; Chew, Paul T K

2009-08-01

To determine if imaging of blebs with anterior segment optical coherence tomography (ASOCT) affects clinical decision-making with regard to laser suture lysis (LSL) after trabeculectomy. In this prospective observational case series, we included patients with poorly controlled intraocular pressure (IOP) after standardized trabeculectomy from May to November 2006. One observer assessed IOP, anterior chamber depth and bleb formation, and recorded a decision of whether or not to undertake LSL based on clinical grounds. A second observer masked to clinical data recorded a decision of whether or not to perform LSL based on ASOCT assessment of scleral flap position, presence of a sub-flap space, patency of the internal ostium, and bleb wall thickening. We compared the 2 observers' decisions to determine how ASOCT influenced decision-making. Seven eyes of 7 patients were included. On the basis of clinical examination, LSL was recommended in all 7 (100.0%) cases due to presence of elevated IOP, deep anterior chambers and poorly formed blebs. Using ASOCT, LSL was recommended in 5/7 (71.4%) cases with apposed scleral flaps, absent sub-flap spaces, and absent bleb wall thickening. In 2/7 (28.7%) cases, LSL was not recommended based on ASOCT findings of an elevated scleral flap, a patent sub-flap space, and bleb wall thickening. All 7 patients had good IOP control and formed blebs at a mean of 8.4+/-2.6 months after trabeculectomy, with a mean IOP of 14.3+/-3.2 mm Hg with no medications. This small study suggests that ASOCT imaging may affect decision-making with regard to LSL by providing information not apparent on clinical examination.

Thermal Decomposition Behaviors and Burning Characteristics of AN/RDX-Based Composite Propellants Supplemented with MnO2 and Fe2O3

NASA Astrophysics Data System (ADS)

Kohga, Makoto; Naya, Tomoki

2015-10-01

Ammonium nitrate (AN)-based composite propellants have gained popularity because of the clean burning nature of AN as an oxidizer. However, such propellants have several disadvantages such as poor ignition and low burning rate. The burning characteristics of the AN propellant were improved when a portion of this propellant was replaced by an energetic material and the addition of a catalyst. In this study, RDX (1,3,5-trinitroperhydro-1,3,5-triazine) was used as the energetic material, and Fe2O3 and MnO2 were used as catalysts. The burning characteristics of the AN/RDX propellants supplemented with catalysts were investigated, and the effects of the replacement of AN by RDX and the catalyst addition were evaluated.

JANNAF 28th Propellant Development and Characterization Subcommittee and 17th Safety and Environmental Protection Subcommittee Joint Meeting. Volume 1

NASA Technical Reports Server (NTRS)

Cocchiaro, James E. (Editor); Mulder, Edwin J. (Editor); Gomez-Knight, Sylvia J. (Editor)

1999-01-01

This volume contains 37 unclassified/unlimited-distribution technical papers that were presented at the JANNAF 28th Propellant Development & Characterization Subcommittee (PDCS) and 17th Safety & Environmental Protection Subcommittee (S&EPS) Joint Meeting, held 26-30 April 1999 at the Town & Country Hotel and the Naval Submarine Base, San Diego, California. Volume II contains 29 unclassified/limited-distribution papers that were presented at the 28th PDCS and 17th S&EPS Joint Meeting. Volume III contains a classified paper that was presented at the 28th PDCS Meeting on 27 April 1999. Topics covered in PDCS sessions include: solid propellant rheology; solid propellant surveillance and aging; propellant process engineering; new solid propellant ingredients and formulation development; reduced toxicity liquid propellants; characterization of hypergolic propellants; and solid propellant chemical analysis methods. Topics covered in S&EPS sessions include: space launch range safety; liquid propellant hazards; vapor detection methods for toxic propellant vapors and other hazardous gases; toxicity of propellants, ingredients, and propellant combustion products; personal protective equipment for toxic liquid propellants; and demilitarization/treatment of energetic material wastes.

Process for Assessing the Stability of HAN (Hydroxylamine)-Based Liquid Propellants.

DTIC Science & Technology

1987-07-29

liquid propellants on the basis of HAN according to Fig. 1 can be determined directly by Fischer titration. This method requires a special unit, as the...Wasserreagenzien nach Eugen Scholz fUr die Karl - Fischer -Titration (Guidelines by Messrs. Riedel-de Haen for Titration according to the Karl Fischer ...Propellant components 2 2.2 Methods of determination 3 2.3 Acid/base titration and pK values 4 2.4 The Titroprozessor 636 8 2.5 Propellant analyses 10

In-space propellant logistics. Volume 4: Project planning data

NASA Technical Reports Server (NTRS)

1972-01-01

The prephase A conceptual project planning data as it pertains to the development of the selected logistics module configuration transported into earth orbit by the space shuttle orbiter. The data represents the test, implementation, and supporting research and technology requirements for attaining the propellant transfer operational capability for early 1985. The plan is based on a propellant module designed to support the space-based tug with cryogenic oxygen-hydrogen propellants. A logical sequence of activities that is required to define, design, develop, fabricate, test, launch, and flight test the propellant logistics module is described. Included are the facility and ground support equipment requirements. The schedule of activities are based on the evolution and relationship between the R and T, the development issues, and the resultant test program.

Energy configuration optimization of submerged propeller in oxidation ditch based on CFD

NASA Astrophysics Data System (ADS)

Wu, S. Y.; Zhou, D. Q.; Zheng, Y.

2012-11-01

The submerged propeller is presented as an important dynamic source in oxidation ditch. In order to guarantee the activated sludge not deposit, it is necessary to own adequate drive power. Otherwise, it will cause many problems such as the awful mixed flow and the great consuming of energy. At present, carrying on the installation optimization of submerged propeller in oxidation ditch mostly depends on experience. So it is necessary to use modern design method to optimize the installation position and number of submerged propeller, and to research submerged propeller flow field characteristics. The submerged propeller internal flow is simulated by using CFD software FLUENT6.3. Based on Navier-Stokes equations and standard k - ɛ turbulence model, the flow was simulated by using a SIMPLE algorithm. The results indicate that the submerged propeller installation position change could avoid the condition of back mixing, which caused by the strong drive. Besides, the problem of sludge deposit and the low velocity in the bend which caused by the drive power attenuation could be solved. By adjusting the submerged propeller number, the least power density that the mixing drive needed could be determined and saving energy purpose could be achieved. The study can provide theoretical guidance for optimize the submerged propeller installation position and determine submerged propeller number.

Use of the omentum in chest-wall reconstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fix, R.J.; Vasconez, L.O.

1989-10-01

Increased use of the omentum in chest-wall reconstruction has paralleled the refinement of anatomic knowledge and the development of safe mobilization techniques. Important anatomic points are the omental attachments to surrounding structures, the major blood supply from the left and right gastroepiploic vessels, and the collateral circulation via the gastroepiploic arch and Barkow's marginal artery. Mobilization of the omentum to the thorax involves division of its attachments to the transverse colon and separation from the greater curvature to fabricate a bipedicled flap. Most anterior chest wounds and virtually all mediastinal wounds can be covered with the omentum based on bothmore » sets of gastroepiploic vessels. The arc of transposition is increased when the omentum is based on a single pedicle, allowing coverage of virtually all chest-wall defects. The final method of increasing flap length involves division of the gastroepiploic arch and reliance on Barkow's marginal artery as collateral circulation to maintain flap viability. With regard to chest-wall reconstruction, we have included the omentum in the armamentarium of flaps used to cover mediastinal wounds. The omentum is our flap of choice for the reconstruction of most radiation injuries of the chest wall. The omentum may also be used to provide protection to visceral anastomoses, vascular conduits, and damaged structures in the chest, as well as to cover defects secondary to tumor excision or trauma. In brief, the omentum has proved to be a most dependable and versatile flap, particularly applicable to chest-wall reconstruction.« less

Synthesis of ethylene diamine-based ferrocene terminated dendrimers and their application as burning rate catalysts.

PubMed

Zain-Ul-Abdin; Wang, Li; Yu, Haojie; Saleem, Muhammad; Akram, Muhammad; Khalid, Hamad; Abbasi, Nasir M; Yang, Xianpeng

2017-02-01

Ferrocene-based derivatives are widely used as ferrocene-based burning rate catalysts (BRCs) for ammonium perchlorate (AP)-based propellant. However, in long storage, small ferrocene-based derivatives migrate to the surface of the propellant, which results in changes in the designed burning parameters and finally causes unstable combustion. To retard the migration of ferrocene-based BRCs in the propellant and to increase the combustion of the solid propellant, zero to third generation ethylene diamine-based ferrocene terminated dendrimers (0G, 1G, 2G and 3G) were synthesized. The synthesis of these dendrimers was confirmed by 1 H NMR and FT-IR spectroscopy. The electrochemical behavior of 0G, 1G, 2G and 3G was investigated by cyclic voltammetry (CV) and the burning rate catalytic activity of 0G, 1G, 2G and 3G on thermal disintegration of AP was examined by thermogravimetry (TG) and differential thermogravimetry (DTG) techniques. Anti-migration studies show that 1G, 2G and 3G exhibit improved anti-migration behavior in the AP-based propellant. Copyright © 2016 Elsevier Inc. All rights reserved.

Acute effects of cigarette smoke exposure on experimental skin flaps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nolan, J.; Jenkins, R.A.; Kurihara, K.

1985-04-01

Random vascular patterned caudally based McFarlane-type skin flaps were elevated in groups of Fischer 344 rats. Groups of rats were then acutely exposed on an intermittent basis to smoke generated from well-characterized research filter cigarettes. Previously developed smoke inhalation exposure protocols were employed using a Maddox-ORNL inhalation exposure system. Rats that continued smoke exposure following surgery showed a significantly greater mean percent area of flap necrosis compared with sham-exposed groups or control groups not exposed. The possible pathogenesis of this observation as well as considerations and correlations with chronic human smokers are discussed. Increased risks of flap necrosis by smokingmore » in the perioperative period are suggested by this study.« less

Long-term results of the island flap palatal pushback.

PubMed

Luce, E A; McClinton, M; Hoopes, J E

1976-09-01

We analyzed all 104 island flap pushback palatal repairs done through our Facial Rehabilitation Clinic in the period from 1965 to 1971. The results were compared to those in a group of 109 standard pushback repairs. The island flap group had a higher incidence of operative complications, of velopharyngeal insufficiency, and of secondary procedures to correct the latter. (The differences between the two groups were not statistically significant, however.) In this group of patients the island flap repair offered no particular advantage over the V-Y or the Dorrance pushback; in fact, it may have been deleterious. A hypothetical explanation for these results is offered, based on possible continuing osteogenesis by the transplanted mucoperiosteum, to produce an inflexible and poorly functioning velum.

To flap or not to flap: a discussion between a fish and a jellyfish

NASA Astrophysics Data System (ADS)

Martin, Nathan; Roh, Chris; Idrees, Suhail; Gharib, Morteza

2016-11-01

Fish and jellyfish are known to swim by flapping and by periodically contracting respectively, but which is the more effective propulsion mechanism? In an attempt to answer this question, an experimental comparison is made between simplified versions of these motions to determine which generates the greatest thrust for the least power. The flapping motion is approximated by pitching plates while periodic contractions are approximated by clapping plates. A machine is constructed to operate in either a flapping or a clapping mode between Reynolds numbers 1,880 and 11,260 based on the average plate tip velocity and span. The effect of the total sweep angle, total sweep time, plate flexibility, and duty cycle are investigated. The average thrust generated and power required per cycle are compared between the two modes when their total sweep angle and total sweep time are identical. In general, operating in the clapping mode required significantly more power to generate a similar thrust compared to the flapping mode. However, modifying the duty cycle for clapping caused the effectiveness to approach that of flapping with an unmodified duty cycle. These results suggest that flapping is the more effective propulsion mechanism within the range of Reynolds numbers tested. This work was supported by the Charyk Bio-inspired Laboratory at the California Institute of Technology, the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469, and the Summer Undergraduate Research Fellowships program.

Numerical and experimental studies of hydrodynamics of flapping foils

NASA Astrophysics Data System (ADS)

Zhou, Kai; Liu, Jun-kao; Chen, Wei-shan

2018-04-01

The flapping foil based on bionics is a sort of simplified models which imitate the motion of wings or fins of fish or birds. In this paper, a universal kinematic model with three degrees of freedom is adopted and the motion parallel to the flow direction is considered. The force coefficients, the torque coefficient, and the flow field characteristics are extracted and analyzed. Then the propulsive efficiency is calculated. The influence of the motion parameters on the hydrodynamic performance of the bionic foil is studied. The results show that the motion parameters play important roles in the hydrodynamic performance of the flapping foil. To validate the reliability of the numerical method used in this paper, an experiment platform is designed and verification experiments are carried out. Through the comparison, it is found that the numerical results compare well with the experimental results, to show that the adopted numerical method is reliable. The results of this paper provide a theoretical reference for the design of underwater vehicles based on the flapping propulsion.

Experimental definition of latissimus dorsi, gracilis, and rectus abdominus musculocutaneous flaps in the dog.

PubMed

Gregory, C R; Gourley, I M; Koblik, P D; Patz, J D

1988-06-01

Dissection and injection studies in canine cadavers and in anesthetized dogs were conducted to determine the feasibility of using the latissimus dorsi, gracilis, and rectus abdominus muscles as musculocutaneous free flaps. Lengths of vascular pedicles for the latissimus dorsi (2 +/- 0.8 cm), gracilis (1.8 +/- 0.8 cm), and rectus abdominus (1.9 +/- 0.9-cm cranial deep epigastric, 1.7 +/- 0.5-cm caudal deep epigastric), as well as arterial diameters (1.28 +/- 0.31-mm thoracodorsal for the latissimus dorsi, 1.10 +/- 0.33-mm muscular branch for the gracilis, 1.25 +/- 0.25-mm cranial deep epigastric and 1.26 +/- 0.32-mm caudal deep epigastric for the rectus abdominus) were considered satisfactory for microvascular transfer. Fluorometry demonstrated overlying cutaneous perfusion in all flaps based on their muscle vascular pedicles, with the exception of the rectus abdominus flap based on the caudal deep epigastric artery. In this instance, up to 20% of the cutaneous element had questionable or no perfusion.

Myosonographic study of abdominal wall dynamics to assess donor site morbidity after microsurgical breast reconstruction with a DIEP or an ms-2 TRAM flap.

PubMed

Seidenstuecker, K; Legler, U; Munder, B; Andree, C; Mahajan, A; Witzel, C

2016-05-01

Currently, autologous breast reconstruction with a free tissue transfer from the lower abdomen is considered to be a safe method that provides a stable long-term solution. The DIEP-flap and the ms-2-TRAM-flap reconstructions have helped reduce donor site morbidity. In order to assess the potential differences between these techniques, we carried out myosonographic evaluations that assessed the muscle dynamics pre- and post-operatively. In addition to investigating the properties of the rectus abdominis muscle post-operatively, this prospective study also allowed us to analyse the muscle preoperatively and to investigate the prospects for harvesting a DIEP-flap as opposed to a TRAM-flap. Sixty patients underwent breast reconstruction with 71 (11 bilateral) free abdominal wall flaps (DIEP-: n = 48; ms-2-TRAM-flap: n = 23). Myosonographic examinations were performed preoperatively and at 3 and 6 months post-operatively. The thickness of the muscle at relaxation and maximum contraction and the difference between the muscle thickness measured at the two states were measured. A general-linear-model (GLM) was used for statistical analysis. The main variable was the surgical method, and the co-variables included BMI and patient age. The decision on whether to harvest a DIEP- or ms-2-TRAM-flap was made intra-operatively and based on the dominant perforator. It shows that the patients who underwent breast reconstruction with a DIEP-flap had significantly better muscle function (p < 0.05) in the follow-up. In addition, the analysis revealed that better muscle function before surgery made it more likely that a patient would undergo a DIEP-flap-reconstruction successfully. Patient age also had a highly significant effect on muscle recovery (p < 0.0005). This prospective study used a dynamic ultrasound evaluation of the abdominal wall and showed that the DIEP-flap significantly reduces donor site morbidity compared to the ms-2-TRAM-flap. The study also showed that good preoperative muscle function might increase the probability of surgeons performing a DIEP-flap reconstruction. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Research on Modeling of Propeller in a Turboprop Engine

NASA Astrophysics Data System (ADS)

Huang, Jiaqin; Huang, Xianghua; Zhang, Tianhong

2015-05-01

In the simulation of engine-propeller integrated control system for a turboprop aircraft, a real-time propeller model with high-accuracy is required. A study is conducted to compare the real-time and precision performance of propeller models based on strip theory and lifting surface theory. The emphasis in modeling by strip theory is focused on three points as follows: First, FLUENT is adopted to calculate the lift and drag coefficients of the propeller. Next, a method to calculate the induced velocity which occurs in the ground rig test is presented. Finally, an approximate method is proposed to obtain the downwash angle of the propeller when the conventional algorithm has no solution. An advanced approximation of the velocities induced by helical horseshoe vortices is applied in the model based on lifting surface theory. This approximate method will reduce computing time and remain good accuracy. Comparison between the two modeling techniques shows that the model based on strip theory which owns more advantage on both real-time and high-accuracy can meet the requirement.

Laminated chemical and physical micro-jet actuators based on conductive media

NASA Astrophysics Data System (ADS)

Gadiraju, Priya D.

2008-04-01

This dissertation presents the development of electrically-powered, lamination-based microactuators for the realization of large arrays of high impulse and short duration micro-jets with potential applications in the field of micro-electro-mechanical systems (MEMS). Microactuators offer unique control opportunities by converting the input electrical or chemical energy stored in a propellant into useful mechanical energy. This small and precise control obtained can potentially be applied towards aerodynamic control and transdermal drug delivery applications. This thesis work discusses the feasibility of using microactuators for two such applications: Control of the motion of a spinning projectile by utilizing the chemically-driven microjets ejected from the actuators, and enhancement of the permeability properties of skin by selectively ablating the stratum corneum layer of skin using the physical microjets ejected from the actuators. This enhanced permeability of skin can later be used for the delivery of high molecular weight drugs for transdermal drug delivery. The development of electrically powered microactuators starts by fabricating an array of radially firing microactuators using lamination-based microfabrication techniques that potentially enable batch fabrication at low cost. The microactuators of this thesis consist of three main parts: a micro chamber in which the propellant is stored; two electrode structures through which electrical energy is supplied to the propellant; and a micro nozzle through which the propellant or released gases from the propellant are expanded as a jet. Once the actuators are fabricated, they are integrated with MEMS-process-compatible propellants and optimized so as to produce instantaneous ignition of the propellant. This instantaneous ignition is achieved either by making the propellant itself conductive, thus, passing an electric current directly through the propellant; or by discharging an arc across the propellant by placing it between two closely spaced electrodes. The first concept is demonstrated for the application of projectile maneuvering where energetic solid propellant is used in generating a high velocity gaseous jet and the second concept is demonstrated for transdermal drug delivery application where a rapid physical jet of a non-energetic propellant is generated. In the case of chemical-based microactuators, the feasibility of using conductive solid propellant based actuators for maneuvering a 25 mm bluff body projectile spinning at 600 Hz is presented. Several conductive solid propellants are developed and characterized for their electrical conductivity and required ignition energy. Finally, the propellant integrated microactuators are characterized for performance in terms of impulse delivered, thrust generated and duration of the jet. These experimental results are then compared to predicted results from simulations. In the case of physical based microactuators, the feasibility of using released physical jets from the microactuator array for transdermal drug delivery application is presented. Several bio-compatible and FDA-approved liquids are used as propellants and are characterized in terms of thrusts delivered and duration of the released jets. These thermo-mechanical jets are then used to expose skin locally so as to create micro conduits in the stratum corneum layer of skin. Both thermal effects and thermo-mechanical effects of the jet on exposed skin are studied. For both cases, histology of exposed skin is presented and its permeability to drug analog molecules is studied.

14 CFR 23.907 - Propeller vibration and fatigue.

Code of Federal Regulations, 2013 CFR

2013-01-01

... based on direct testing of the propeller on the airplane and engine installation for which approval is... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood...

14 CFR 23.907 - Propeller vibration and fatigue.

Code of Federal Regulations, 2014 CFR

2014-01-01

... based on direct testing of the propeller on the airplane and engine installation for which approval is... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood...

Surgical Repair of Mid-shaft Hypospadias Using a Transverse Preputial Island Flap and Pedicled Dartos Flap Around Urethral Orifice.

PubMed

Liang, Weiqiang; Ji, Chenyang; Chen, Yuhong; Zhang, Ganling; Zhang, Jiaqi; Yao, Yuanyuan; Zhang, Jinming

2016-08-01

To evaluate the effects, particularly the incidence of anastomotic fistula, of a pedicled dartos flap around the urethral orifice in the treatment of urethroplasty of mid-shaft hypospadias. A total of 46 cases of congenital mid-shaft hypospadias were included in this study. The patients ranged in age from 0.7 to 25.4 years and the average was 5.8 years. The patients received penis chordee correction. A transverse preputial island flap was developed for urethral reconstruction. The proximal dartos of the urethral orifice was used to develop a pedicled dartos flap, which was transposed to cover and strengthen neourethral anastomosis. The ventral penile skin defect was repaired by another flap. The 46 patients were examined during follow-up visits for 6 months to 3 years. An anastomotic fistula was observed in one case (2.2 %). Scar healing without fistula was observed in another patient due to poor blood supply to part of the ventral penile skin. No other incidences of fistula, urethral rupture, flap necrosis, wound infections, urinary tract (meatal) stenosis, or urethral diverticulum were observed in the patients. A pedicled dartos flap around the urethral orifice can take advantage of well-vascularized local tissue to add a protective layer to the proximal aspect of the neourethral anastomosis for reducing the incidence of anastomotic fistula in mid-shaft hypospadias repair using a transverse preputial island flap. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Cost-Utility Analysis: Sartorius Flap versus Negative Pressure Therapy for Infected Vascular Groin Graft Managment.

PubMed

Chatterjee, Abhishek; Macarios, David; Griffin, Leah; Kosowski, Tomasz; Pyfer, Bryan J; Offodile, Anaeze C; Driscoll, Daniel; Maddali, Sirish; Attwood, John

2015-11-01

Sartorius flap coverage and adjunctive negative pressure wound therapy (NPWT) have been described in managing infected vascular groin grafts with varying cost and clinical success. We performed a cost-utility analysis comparing sartorius flap with NPWT in managing an infected vascular groin graft. A literature review compiling outcomes for sartorius flap and NPWT interventions was conducted from peer-reviewed journals in MEDLINE (PubMed) and EMBASE. Utility scores were derived from expert opinion and used to estimate quality-adjusted life years (QALYs). Medicare current procedure terminology and diagnosis-related groups codes were used to assess the costs for successful graft salvage with the associated complications. Incremental cost-effectiveness was assessed at $50,000/QALY, and both univariate and probabilistic sensitivity analyses were conducted to assess robustness of the conclusions. Thirty-two studies were used pooling 384 patients (234 sartorius flaps and 150 NPWT). NPWT had better clinical outcomes (86.7% success rate, 0.9% minor complication rate, and 13.3% major complication rate) than sartorius flap (81.6% success rate, 8.0% minor complication rate, and 18.4% major complication rate). NPWT was less costly ($12,366 versus $23,516) and slightly more effective (12.06 QALY versus 12.05 QALY) compared with sartorius flap. Sensitivity analyses confirmed the robustness of the base case findings; NPWT was either cost-effective at $50,000/QALY or dominated sartorius flap in 81.6% of all probabilistic sensitivity analyses. In our cost-utility analysis, use of adjunctive NPWT, along with debridement and antibiotic treatment, for managing infected vascular groin graft wounds was found to be a more cost-effective option when compared with sartorius flaps.

Cost-Utility Analysis: Sartorius Flap versus Negative Pressure Therapy for Infected Vascular Groin Graft Managment

PubMed Central

Macarios, David; Griffin, Leah; Kosowski, Tomasz; Pyfer, Bryan J.; Offodile, Anaeze C.; Driscoll, Daniel; Maddali, Sirish; Attwood, John

2015-01-01

Background: Sartorius flap coverage and adjunctive negative pressure wound therapy (NPWT) have been described in managing infected vascular groin grafts with varying cost and clinical success. We performed a cost–utility analysis comparing sartorius flap with NPWT in managing an infected vascular groin graft. Methods: A literature review compiling outcomes for sartorius flap and NPWT interventions was conducted from peer-reviewed journals in MEDLINE (PubMed) and EMBASE. Utility scores were derived from expert opinion and used to estimate quality-adjusted life years (QALYs). Medicare current procedure terminology and diagnosis-related groups codes were used to assess the costs for successful graft salvage with the associated complications. Incremental cost-effectiveness was assessed at $50,000/QALY, and both univariate and probabilistic sensitivity analyses were conducted to assess robustness of the conclusions. Results: Thirty-two studies were used pooling 384 patients (234 sartorius flaps and 150 NPWT). NPWT had better clinical outcomes (86.7% success rate, 0.9% minor complication rate, and 13.3% major complication rate) than sartorius flap (81.6% success rate, 8.0% minor complication rate, and 18.4% major complication rate). NPWT was less costly ($12,366 versus $23,516) and slightly more effective (12.06 QALY versus 12.05 QALY) compared with sartorius flap. Sensitivity analyses confirmed the robustness of the base case findings; NPWT was either cost-effective at $50,000/QALY or dominated sartorius flap in 81.6% of all probabilistic sensitivity analyses. Conclusion: In our cost–utility analysis, use of adjunctive NPWT, along with debridement and antibiotic treatment, for managing infected vascular groin graft wounds was found to be a more cost-effective option when compared with sartorius flaps. PMID:26893991

Bilobed perforator free flaps for combined hemitongue and floor-of-the-mouth defects.

PubMed

Longo, B; Ferri, G; Fiorillo, A; Rubino, C; Santanelli, F

2013-11-01

Combined hemiglossectomy and floor-of-the-mouth defects need accurate reconstructive planning to restore swallowing and speech function. The aim of this prospective study was to evaluate outcomes of the bilobed design applied to perforator free flaps for combined hemitongue and floor-of-the-mouth defects. Twelve patients with a mean age of 71 years (range, 60-84) addressed to combined hemiglossectomy and floor-of-the-mouth resection and bilobed-shaped perforator free-flap reconstruction were prospectively enrolled. Defects were classified as follows: type 1, including only the anterior mobile portion of the tongue (n = 3); type 2, involving both mobile tongue and tongue base (n = 6); and type 3, including segmental mandibulectomy combined with a type 1 or type 2 defect (n = 3). The Kruskal-Wallis and Bonferroni post hoc tests were used to compare outcomes. Type 1 defects were reconstructed by three anterolateral thigh (ALT) perforator flaps; type 2 defects were reconstructed by four ALT flaps and two vertical deep inferior epigastric perforator flaps; and type 3 defects were restored by three osteocutaneous fibula flaps. Eleven flaps (91.6%) healed uneventfully, while one (8.4%) suffered a small area of skin necrosis whose revision did not compromise functional results. Six patients achieved normal intelligible speech, five had acceptable intelligible speech and one had unintelligible speech (p = 0.356). Swallowing function was considered normal in eight patients and with mild impairment in four (p = 0.178). Cosmesis resulted excellent in seven patients and good in five (p = 0.855). The bilobed-shaped perforator free flaps were shown to be a safe and predictable solution for combined hemitongue and floor-of-the-mouth defects providing optimal aesthetic and functional outcomes. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Use of Pedicled Trapezius Myocutaneous Flap for Posterior Skull Reconstruction.

PubMed

Singh, Mansher; Rios Diaz, Arturo J; Cauley, Ryan; Smith, Timothy R; Caterson, E J

2015-09-01

Soft-tissue defects in posterior skull can be challenging for reconstruction. If related to tumor resection, these wound beds are generally irradiated and can be difficult from a recipient-vessel perspective for a free tissue transfer. Locoregional flaps might prove to be important reconstructive option in such patients. There is a very limited data on the usage of pedicled trapezius myocutaneous flaps for such defects. The authors reviewed existing study for usage of trapezius flap for posterior skull repair and used pedicled trapezius myocutaneous flaps based on the descending branch of superficial cervical artery (SCA) for reconstruction of posterior skull soft-tissue defect in an irradiated and infected wound. Two patients were operated for trapezius myocutaneous flap for posterior skull defects complicated by cerebrospinal fluid (CSF) leakage and epidural abscess. There was no recipient or donor-site complication at a mean follow-up of 12.5 months. Neither of the 2 patients had any functional deficits for the entire duration of the follow-up. Although this flap was able to help in controlling the CSF leakage in the first patient, it successfully healed the cavity generated from epidural abscess drainage in the second patient. The large angle of rotation coupled with the ability to complete the procedure without repositioning the patients makes trapezius myocutaneous flap an attractive option for posterior skull reconstruction. In our limited experience, the pedicled trapezius flaps are a reliable alternative as they are well vascularized and able to obliterate the soft-tissue defect completely. The recipient site healed completely in infected as well as irradiated wound beds. In addition, the donor site can be primarily closed with minimal donor-associated complication.

Peroneal perforator-based peroneus longus tendon and sural neurofasciocutaneous composite flap transfer for a large soft-tissue defect of the forearm: A case report.

PubMed

Hayashida, Kenji; Saijo, Hiroto; Fujioka, Masaki

2018-01-01

We describe the use of a composite flap composed of a sural neurofasciocutaneous flap and a vascularized peroneus longus tendon for the reconstruction of severe composite forearm tissue defects in a patient. A 43-year-old man had his left arm caught in a conveyor belt resulting in a large soft-tissue defect of 18 × 11 cm over the dorsum forearm. The extensor carpi radialis, superficial radial nerve, and radial artery were severely damaged. A free neurofasciocutaneous composite flap measuring 16 × 11 cm was outlined on the patient's left lower leg to allow simultaneous skin, tendon, nerve, and artery reconstruction. The flap, which included the peroneus longus tendon, was elevated on the subfascial plane. After the flap was transferred to the recipient site, the peroneal artery was anastomosed to the radial artery in a flow-through manner. The vascularized tendon graft with 15 cm in length was used to reconstruct the extensor carpi radialis longus tendon defect using an interlacing suture technique. As the skin paddle of the sural neurofasciocutaneous flap and the vascularized peroneus longus tendon graft were linked by the perforator and minimal fascial tissue, the skin paddle was able to rotate and slide with comparative ease. The flap survived completely without any complications. The length of follow-up was 12 months and was uneventful. Range of motion of his left wrist joint was slightly limited to 75 degrees. This novel composite flap may be useful for reconstructing long tendon defects associated with extensive forearm soft tissue defects. © 2016 Wiley Periodicals, Inc.

Circulation control propellers for general aviation, including a BASIC computer program

NASA Technical Reports Server (NTRS)

Taback, I.; Braslow, A. L.; Butterfield, A. J.

1983-01-01

The feasibility of replacing variable pitch propeller mechanisms with circulation control (Coanada effect) propellers on general aviation airplanes was examined. The study used a specially developed computer program written in BASIC which could compare the aerodynamic performance of circulation control propellers with conventional propellers. The comparison of aerodynamic performance for circulation control, fixed pitch and variable pitch propellers is based upon the requirements for a 1600 kg (3600 lb) single engine general aviation aircraft. A circulation control propeller using a supercritical airfoil was shown feasible over a representative range of design conditions. At a design condition for high speed cruise, all three types of propellers showed approximately the same performance. At low speed, the performance of the circulation control propeller exceeded the performance for a fixed pitch propeller, but did not match the performance available from a variable pitch propeller. It appears feasible to consider circulation control propellers for single engine aircraft or multiengine aircraft which have their propellers on a common axis (tractor pusher). The economics of the replacement requires a study for each specific airplane application.

Risk-Based Explosive Safety Analysis

DTIC Science & Technology

2016-11-30

safety siting of energetic liquids and propellants can be greatly aided by the use of risk-based methodologies. The low probability of exposed...liquids or propellants . 15. SUBJECT TERMS N/A 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF...of energetic liquids and propellants can be greatly aided by the use of risk-based methodologies. The low probability of exposed personnel and the

A conserved loop-wedge motif moderates reaction site search and recognition by FEN1.

PubMed

Thompson, Mark J; Gotham, Victoria J B; Ciani, Barbara; Grasby, Jane A

2018-06-07

DNA replication and repair frequently involve intermediate two-way junction structures with overhangs, or flaps, that must be promptly removed; a task performed by the essential enzyme flap endonuclease 1 (FEN1). We demonstrate a functional relationship between two intrinsically disordered regions of the FEN1 protein, which recognize opposing sides of the junction and order in response to the requisite substrate. Our results inform a model in which short-range translocation of FEN1 on DNA facilitates search for the annealed 3'-terminus of a primer strand, which is recognized by breaking the terminal base pair to generate a substrate with a single nucleotide 3'-flap. This recognition event allosterically signals hydrolytic removal of the 5'-flap through reaction in the opposing junction duplex, by controlling access of the scissile phosphate diester to the active site. The recognition process relies on a highly-conserved 'wedge' residue located on a mobile loop that orders to bind the newly-unpaired base. The unanticipated 'loop-wedge' mechanism exerts control over substrate selection, rate of reaction and reaction site precision, and shares features with other enzymes that recognize irregular DNA structures. These new findings reveal how FEN1 precisely couples 3'-flap verification to function.

Green Application for Space Power

NASA Technical Reports Server (NTRS)

Robinson, Joel

2015-01-01

Most space vehicle auxiliary power units (APUs) use hydrazine propellant for generating power. Hydrazine is a toxic, hazardous fuel that requires special safety equipment and processes for handling and loading. In recent years, there has been development of two green propellants (less toxic) that could enable their use in APUs. The Swedish government, in concert with the Swedish Space Corporation, has developed a propellant based on ammonium dinitramide (LMP-103S) that was flown on the Prisma spacecraft in 2010. The United States Air Force (USAF) has been developing a propellant based on hydroxylammonium nitrate (AFM315E) that is scheduled to fly on the Green Propellant Infusion Mission in the spring of 2016 to demonstrate apogee and reaction control thrusters. However, no one else in the Agency is currently pursuing use of green propellants for application to the APUs. Per the TA-01 Launch Propulsion Roadmap, the Space Technology Mission Directorate had identified the need to have a green propellant APU by 2015. This is our motivation for continuing activities.

A prospective randomized cost billing comparison of local fasciocutaneous perforator versus free Gracilis flap reconstruction for lower limb in a developing economy.

PubMed

Abdelrahman, Islam; Moghazy, Amr; Abbas, Ashraf; Elmasry, Moustafa; Adly, Osama; Elbadawy, Mohamed; Steinvall, Ingrid; Sjoberg, Folke

2016-08-01

Distal half leg complex wounds are usually a formidable problem that necessitates either local or free flap coverage. The aim of this study was to compare cost billing charges in free Gracilis flap (fGF) and local fasciocutaneous perforator flap (lFPF) in reconstructing complex soft tissue leg and foot defects. Thirty consecutive adult (>15-year-old) patients with soft tissue defects in the leg and/or foot requiring tissue coverage with a flap in the period between 2012 and 2015 were randomly assigned (block randomization) to either an fGF or lFPF procedure. The outcome measures addressed were total billed charges costs, perioperative billed charges cost, partial or complete flap loss, length of hospital stay, inpatient postsurgical care duration, complications, operating time and number of operative scrub staff. One patient suffered from complete flap loss in each group. Reconstruction with lFPF showed total lower billed charges costs by 62% (2509 USD) (p < 0.001) and perioperative billed charges cost by 54% (779 USD) (p < 0.001), and shorter total hospital stay (36.5 days; p < 0.001), inpatient postsurgical care duration (6.4 days; p < 0.001), operating time (4.3 h; p < 0.001) and fewer scrub staff (2.2 persons; p < 0.001). These results suggest that neither flap is totally superior to the other; the choice should instead be based on the outcome sought and logistics. lFPF requires lower billed charges cost and resource use and saves operative time and personnel and reduces length of hospital stay. Our approach changed towards using perforator flaps in medium-sized defects, keeping the free flap option for larger defects. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Free sural artery perforator flap: An occasional gift in oral cavity reconstruction.

PubMed

Pease, Natalie L; Davies, Andrew; Townley, William A

2016-07-01

The medial sural artery perforator (MSAP) flap is becoming a popular strategy for reconstructing intraoral defects. We present a case in which no MSAPs were present, however, a perforator-based calf flap was successfully raised on the sural artery and used for tongue reconstruction. A corresponding anatomic study was undertaken to establish if this finding was reproducible. A 58-year-old woman underwent left hemiglossectomy for a squamous cell carcinoma of the tongue. Subsequently, 6 fresh frozen cadaveric limbs were dissected examining the blood supply of the posterior calf skin. The sural artery perforator (SAP) flap successfully reconstructed the defect. Our cadaveric study similarly demonstrated a septocutaneous SAP supplying the posterior calf skin in 1 of 6 limbs. SAPs allow a favorable flap dissection, as opposed to the musculocutaneous course of MSAPs. Our findings provide further evidence of the versatility of the calf donor site. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2454-E2456, 2016. © 2016 Wiley Periodicals, Inc.

[Perineal reconstruction: Salvage surgery with 2flaps technique].

PubMed

Jiménez Gómez, Marta; Navarro-Sánchez, Antonio; Lima Sánchez, Jaime; Hernández Hernández, Juan Ramón

2017-12-01

The principles of perineal reconstructive surgery comprise adequate filling of the defect along with stable and durable skin coverage, with a low morbidity rate. Two-flap perineal reconstruction is a simple, fast and reliable technique that uses a single donor site. This improves scar position with low morbidity. It is based in the use of 2flaps; one flap fills the defect with a «turn over» technique and the other is a rotation - advancement flap for skin coverage. A 52-year-old male diagnosed with Lynch syndrome who underwent laparoscopic abdominoperineal amputation for adenocarcinoma of the lower rectum and developed recurrence 2years later over the perineal scar that required radical resection and perineal reconstruction. The use of this approach facilitates perineal reconstruction and enables treatment of patients with large and complex defects in frequently irradiated tissues where wound dehiscence and infection are common. Copyright © 2017 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

The design and analysis of simple low speed flap systems with the aid of linearized theory computer programs

NASA Technical Reports Server (NTRS)

Carlson, Harry W.

1985-01-01

The purpose here is to show how two linearized theory computer programs in combination may be used for the design of low speed wing flap systems capable of high levels of aerodynamic efficiency. A fundamental premise of the study is that high levels of aerodynamic performance for flap systems can be achieved only if the flow about the wing remains predominantly attached. Based on this premise, a wing design program is used to provide idealized attached flow camber surfaces from which candidate flap systems may be derived, and, in a following step, a wing evaluation program is used to provide estimates of the aerodynamic performance of the candidate systems. Design strategies and techniques that may be employed are illustrated through a series of examples. Applicability of the numerical methods to the analysis of a representative flap system (although not a system designed by the process described here) is demonstrated in a comparison with experimental data.

The investigation of a variable camber blade lift control for helicopter rotor systems

NASA Technical Reports Server (NTRS)

Awani, A. O.

1982-01-01

A new rotor configuration called the variable camber rotor was investigated numerically for its potential to reduce helicopter control loads and improve hover performance. This rotor differs from a conventional rotor in that it incorporates a deflectable 50% chord trailing edge flap to control rotor lift, and a non-feathering (fixed) forward portion. Lift control is achieved by linking the blade flap to a conventional swashplate mechanism; therefore, it is pilot action to the flap deflection that controls rotor lift and tip path plane tilt. This report presents the aerodynamic characteristics of the flapped and unflapped airfoils, evaluations of aerodynamics techniques to minimize flap hinge moment, comparative hover rotor performance and the physical concepts of the blade motion and rotor control. All the results presented herein are based on numerical analyses. The assessment of payoff for the total configuration in comparison with a conventional blade, having the same physical characteristics as an H-34 helicopter rotor blade was examined for hover only.

Zygomatico-maxillary Reconstruction with Computer-aided Manufacturing of a Free DCIA Osseous Flap and Intraoral Anastomoses.

PubMed

Roy, Andrée-Anne; Efanov, Johnny I; Mercier-Couture, Geneviève; Chollet, André; Borsuk, Daniel E

2017-02-01

Craniomaxillofacial reconstruction using virtual surgical planning, computer-aided manufacturing, and new microsurgical techniques optimizes patient-specific and defect-directed reconstruction. A 3D customized free deep circumflex iliac artery (DCIA) flap with intraoral anastomoses was performed on a 23-year-old man with a posttraumatic right zygomatico-maxillary defect with failure of alloplastic implant reconstruction. An osseous iliac crest flap was sculpted based on a customized 3D model of the mirror image of the patient's unaffected side to allow for perfect fit to the zygomatico-maxillary defect. An intraoral dissection of the facial artery and vein was performed within the right cheek mucosa and allowed for end-to-end microvascular anastomoses. 3D preoperative planning and customized free DCIA osseous flap combined with an intraoral microsurgical technique provided restoration of facial esthetics and function without visible scars. In cases where zygomatico-malar reconstruction by alloplastic material fails, a customized free DCIA osseous flap can be designed by virtual surgical planning to restore facial appearance and function.

Beneficial aerodynamic effect of wing scales on the climbing flight of butterflies.

PubMed

Slegers, Nathan; Heilman, Michael; Cranford, Jacob; Lang, Amy; Yoder, John; Habegger, Maria Laura

2017-01-30

It is hypothesized that butterfly wing scale geometry and surface patterning may function to improve aerodynamic efficiency. In order to investigate this hypothesis, a method to measure butterfly flapping kinematics optically over long uninhibited flapping sequences was developed. Statistical results for the climbing flight flapping kinematics of 11 butterflies, based on a total of 236 individual flights, both with and without their wing scales, are presented. Results show, that for each of the 11 butterflies, the mean climbing efficiency decreased after scales were removed. Data was reduced to a single set of differences of climbing efficiency using are paired t-test. Results show a mean decrease in climbing efficiency of 32.2% occurred with a 95% confidence interval of 45.6%-18.8%. Similar analysis showed that the flapping amplitude decreased by 7% while the flapping frequency did not show a significant difference. Results provide strong evidence that butterfly wing scale geometry and surface patterning improve butterfly climbing efficiency. The authors hypothesize that the wing scale's effect in measured climbing efficiency may be due to an improved aerodynamic efficiency of the butterfly and could similarly be used on flapping wing micro air vehicles to potentially achieve similar gains in efficiency.

Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

NASA Technical Reports Server (NTRS)

Kottapalli, Sesi B. R.

2010-01-01

Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

Influence of minoxidil on ischemic cutaneous flaps in rats.

PubMed

Bittencourt, Rogério de Castro; Biondo-Simões, Maria de Lourdes Pessole; Paula, Josué Brunginski de; Martynetz, Juliano; Groth, Anne

2005-01-01

To evaluate the influence of minoxidil, a well known vasodilator, on ischemic flap necrosis prevention in rats. Ventral cutaneous flaps, measuring 8x4 cm, were designed in 20 Wistar rats based on the right cranial epigastric artery. In the experiment group, 50 mg/kg/day of minoxidil sulfate was administered by orogastric tube and the same amount of saline solution was administered to the control group. Such procedure was initiated 24 h before surgery and kept once a day through the 7th postoperative day. Microcirculation was evaluated with laser fluxometry 24 h before surgical procedure, at immediate postoperative and at the 7th postoperative day. Flap necrosis area was evaluated by 2 methods: planimetry and weight/paper ratio. A significant flow increase in distal and medial extremity at M1 (medial point 1) (p=0.0484) was observed in the experiment group. There was significant difference in flap necrosis prevention in the experiment group (p=0.0433), although after necrosis took place there was no significant difference in necrosis size. (p=0.1051 and p=0.2799). Minoxidil sulfate is effective in avoiding necrosis in ischemic flaps, but after necrosis is present there is no difference in survival area between experimental and control groups.

14. INTERIOR VIEW OF PROPELLER STAND CONTROL ROOM. WrightPatterson ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. INTERIOR VIEW OF PROPELLER STAND CONTROL ROOM. - Wright-Patterson Air Force Base, Area B, Building No. 20A, Propeller Test Complex, Seventh Street, from E to G Streets, Dayton, Montgomery County, OH

6. INTERIOR VIEW, DETAIL OF PROPELLER TEST STAND. WrightPatterson ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. INTERIOR VIEW, DETAIL OF PROPELLER TEST STAND. - Wright-Patterson Air Force Base, Area B, Building No. 20A, Propeller Test Complex, Seventh Street, from E to G Streets, Dayton, Montgomery County, OH

View of foundry/propeller shop (building no. 20) looking northeast. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of foundry/propeller shop (building no. 20) looking northeast. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Foundry-Propeller Shop, North of Porter Avenue, west of Third Street West, Philadelphia, Philadelphia County, PA

Rational functional representation of flap noise spectra including correction for reflection effects

NASA Technical Reports Server (NTRS)

Miles, J. H.

1974-01-01

A rational function is presented for the acoustic spectra generated by deflection of engine exhaust jets for under-the-wing and over-the-wing versions of externally blown flaps. The functional representation is intended to provide a means for compact storage of data and for data analysis. The expressions are based on Fourier transform functions for the Strouhal normalized pressure spectral density, and on a correction for reflection effects based on Thomas' (1969) N-independent-source model extended by use of a reflected ray transfer function. Curve fit comparisons are presented for blown-flap data taken from turbofan engine tests and from large-scale cold-flow model tests. Application of the rational function to scrubbing noise theory is also indicated.

Triple flap technique for vulvar reconstruction.

PubMed

Mercut, R; Sinna, R; Vaucher, R; Giroux, P A; Assaf, N; Lari, A; Dast, S

2018-04-09

Perineal defects are encountered ever more frequently, in the treatment of vulvar cancers or abdominoperineal resection. The surgical treatment of vulvar cancer leads to significant skin defect. The aim of the reconstruction is not to provide volume but rather to resurface perineum. We propose a new solution to cover the extensive skin defect remaining after excision. We report 3 patients who underwent large excision for vulvar cancer, with lymph node dissection. For reconstruction, we performed 3 advancement flaps. Two V-Y flaps cantered on the infra-gluteal folds and based on pudendal perforator arteries were used to cover the postero-lateral parts of the defect. The third advancement flap from the superior aspect of the defect was a Y-V Mons pubis flap. The defects were successfully covered by the 3 flap technique. The first patient suffered a non-union that slowly healed by secondary intention. For the other cases, we used the same technique, but applied negative pressure wound therapy on the sutures, with excellent results. The 3 flap technique is a simple and reliable method and the donor site morbidity is minimal. It can be realised without changing the position of the patient after tumour excision, and does not require delicate perforator dissection. This surgical option can be easily applied, allowing better management of these cases. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

The Lateral Proximal Phalanx Flap for Contractures and Soft Tissue Defects in the Proximal Interphalangeal Joint: An Anatomical and Clinical Study.

PubMed

Beltrán, Aldo G; Romero, Camilo J

2017-01-01

Background: The management of contractures and soft tissue defects in the proximal interphalangeal (PIP) finger joint remains a challenge. We report a transposition flap from the lateral skin of the proximal phalanx that is based on perforating branches of the digital arteries and can be used safely for both palmar and dorsal cover defects. Methods: We first completed an anatomic study, dissecting 20 fingers in fresh cadavers with arterial injections and made the new flap in patients with dorsal or palmar defects in PIP joints. Results: In cadavers, we can reveal 4 constant branches from each digital artery in the proximal phalanx, with the more distal just in the PIP joint constituting the flap pedicle. Between February 2010 and February 2015, we designed 33 flaps in 29 patients, 7 for dorsal and 26 for palmar defects, with no instances of flap necrosis and 4 distal epidermolysis. The patients were between 4 and 69 years with no major complications, and all of the skin defects in the PIP joint were resolved satisfactorily without any relevant sequelae at the donor site. Conclusions: This flap procedure is an easy, reliable, versatile, and safe technique, and could be an important tool for the management of difficult skin defects and contractures at the PIP joint level.

Ecosystem Food Web Lift-The-Flap Pages

ERIC Educational Resources Information Center

Atwood-Blaine, Dana; Rule, Audrey C.; Morgan, Hannah

2016-01-01

In the lesson on which this practical article is based, third grade students constructed a "lift-the-flap" page to explore food webs on the prairie. The moveable papercraft focused student attention on prairie animals' external structures and how the inferred functions of those structures could support further inferences about the…

A Study about the Taboo of Rotation Timing for the Flapping Wing Flight

NASA Astrophysics Data System (ADS)

Wang, An-Bang; Hsueh, Chia-Hsien; Chen, Shih-Shen

2004-11-01

Influence of rotation timing for flapping wing flight on the flying lift has been experimentally investigated in this study. Since the insects cannot extend and shrink their wings like birds, the rotation timing of wings becomes the major influential factor to affect the flying lift of the flapping wing flight. The results reveal that rotation timing has significant influence on the flying lift. The averaged flying lift increases for high rotation wing velocity. Based on the comparisons of flying lift, too late A-rotation (connecting from wing downward motion to upward one) is the most serious taboo for the motion design of the micro air vehicles with flapping wings. Too late B-rotation (connection from upward motion to downward one) should also be avoided.

A low speed wind tunnel investigation of Reynolds number effects on a 60-deg swept wing configuration with leading and trailing edge flaps

NASA Technical Reports Server (NTRS)

Rao, Dhanvada M.; Hoffler, Keith D.

1988-01-01

A low-speed wind tunnel test was performed to investigate Reynolds number effects on the aerodynamic characteristics of a supersonic cruise wing concept model with a 60-deg swept wing incorporating leading-edge and trailing-edge flap deflections. The Reynolds number ranged from 0.3 to 1.6 x 10 to the 6th, and corresponding Mach numbers from .05 to 0.3. The objective was to define a threshold Reynolds number above which the flap aerodynamics basically remained unchanged, and also to generate a data base useful for validating theoretical predictions for the Reynolds number effects on flap performance. This report documents the test procedures used and the basic data acquired in the investigation.

Noise characteristics of upper surface blown configurations. Experimental program and results

NASA Technical Reports Server (NTRS)

Brown, W. H.; Searle, N.; Blakney, D. F.; Pennock, A. P.; Gibson, J. S.

1977-01-01

An experimental data base was developed from the model upper surface blowing (USB) propulsive lift system hardware. While the emphasis was on far field noise data, a considerable amount of relevant flow field data were also obtained. The data were derived from experiments in four different facilities resulting in: (1) small scale static flow field data; (2) small scale static noise data; (3) small scale simulated forward speed noise and load data; and (4) limited larger-scale static noise flow field and load data. All of the small scale tests used the same USB flap parts. Operational and geometrical variables covered in the test program included jet velocity, nozzle shape, nozzle area, nozzle impingement angle, nozzle vertical and horizontal location, flap length, flap deflection angle, and flap radius of curvature.

Passive Porous Treatment for Reducing Flap Side-Edge Noise

NASA Technical Reports Server (NTRS)

Choudhari, Meelan M.; Khorrami, Mehdi R.

2008-01-01

A passive porous treatment has been proposed as a means of suppressing noise generated by the airflow around the side edges of partial-span flaps on airplane wings when the flaps are extended in a high-lift configuration. The treatment proposed here does not incur any aerodynamic penalties and could easily be retrofit to existing airplanes. The treatment could also be applied to reduce noise generated by turbomachinery, including wind turbines. Innovative aspects of the proposed treatment include a minimum treatment area and physics-based procedure for treatment design. The efficacy of the treatment was confirmed during wind-tunnel experiments at NASA Ames, wherein the porous treatment was applied to a minute surface area in the vicinity of a flap edge on a 26-percent model of Boeing 777-200 wing.

Detached Eddy Simulation of Flap Side-Edge Flow

NASA Technical Reports Server (NTRS)

Balakrishnan, Shankar K.; Shariff, Karim R.

2016-01-01

Detached Eddy Simulation (DES) of flap side-edge flow was performed with a wing and half-span flap configuration used in previous experimental and numerical studies. The focus of the study is the unsteady flow features responsible for the production of far-field noise. The simulation was performed at a Reynolds number (based on the main wing chord) of 3.7 million. Reynolds Averaged Navier-Stokes (RANS) simulations were performed as a precursor to the DES. The results of these precursor simulations match previous experimental and RANS results closely. Although the present DES simulations have not reached statistical stationary yet, some unsteady features of the developing flap side-edge flowfield are presented. In the final paper it is expected that statistically stationary results will be presented including comparisons of surface pressure spectra with experimental data.

Cost analysis in oral cavity and oropharyngeal reconstructions with microvascular and pedicled flaps.

PubMed

Deganello, A; Gitti, G; Parrinello, G; Muratori, E; Larotonda, G; Gallo, O

2013-12-01

Reconstructive surgery of the head and neck region has undergone tremendous advancement over the past three decades, and the success rate of free tissue transfers has risen to greater than 95%. It must always be considered that not all patients are ideal candidates for free flap reconstruction, and also that not every defect strictly requires a free flap transfer to achieve good functional results. At our institution, free flap reconstruction is first choice, although we use pedicled alternative flaps for most weak patients suffering from severe comorbidities, and for pretreated patients presenting a second primary or a recurrent cancer. From July 2006 to May 2010, 54 consecutive patients underwent soft tissue reconstruction of oral cavity and oropharyngeal defects. We divided the cohort in three groups: Group 1 (G1): 16 patients in good general conditions that received free radial forearm flap reconstruction; Group 2 (G2): 18 high-risk patients that received a reconstruction with infrahyoid flap; Group 3 (G3): 20 patients that received temporal flap (10 cases) or pectoral flap (10 cases) reconstruction. We must highlight that pedicled alternative flaps were used in elderly, unfavourable and weak patients, where usually the medical costs tend to rise rather than decrease. We compared the healthcare costs of the three groups, calculating real costs in each group from review of medical records and operating room registers, and calculating the corresponding DRG system reimbursement. For real costs, we found a statistically significant difference among groups: in G1 the average total cost per patient was € 22,924, in G2 it was € 18,037 and in G3 was € 19,872 (p = 0.043). The amount of the refund, based on the DRG system, was € 7,650 per patient, independently of the type of surgery. Our analysis shows that the use of alternative non-microvascular techniques, in high-risk patients, is functionally and oncologically sound, and can even produce a cost savings. In particular, the infrahyoid flap (G2) ensures excellent functional results, accompanied by the best economic savings in the worst group of patients. Our data reflect a large disconnection between the DRG system and actual treatment costs.

Preoperative computed tomography angiography for planning DIEP flap breast reconstruction reduces operative time and overall complications

PubMed Central

Rozen, Warren Matthew; Chowdhry, Muhammad; Band, Bassam; Ramakrishnan, Venkat V.; Griffiths, Matthew

2016-01-01

Background The approach and operative techniques associated with breast reconstruction have steadily been refined since its inception, with abdominal perforator-based flaps becoming the gold standard reconstructive option for women undergoing breast cancer surgery. The current study comprises a cohort of 632 patients, in whom specific operative times are recorded by a blinded observer, and aims to address the potential benefits seen with the use of computer tomography (CT) scanning preoperatively on operative outcomes, complications and surgical times. Methods A prospectively recorded, retrospective review was undertaken of patients undergoing autologous breast reconstruction with a DIEP flap at the St Andrews Centre over a 4-year period from 2010 to 2014. Computed tomography angiography (CTA) scanning of patients began in September 2012 and thus 2 time periods were compared: 2 years prior to the use of CTA scans and 2 years afterwards. For all patients, key variables were collected including patient demographics, operative times, flap harvest time, pedicle length, surgeon experience and complications. Results In group 1, comprising patients within the period prior to CTA scans, 265 patients underwent 312 flaps; whilst in group 2, the immediately following 2 years, 275 patients had 320 flaps. The use of preoperative CTA scans demonstrated a significant reduction in flap harvest time of 13 minutes (P<0.013). This significant time saving was seen in all flap modifications: unilateral, bilateral and bipedicled DIEP flaps. The greatest time saving was seen in bipedicle flaps, with a 35-minute time saving. The return to theatre rate significantly dropped from 11.2% to 6.9% following the use of CTA scans, but there was no difference in the total failure rate. Conclusions The study has demonstrated both a benefit to flap harvest time as well as overall operative times when using preoperative CTA. The use of CTA was associated with a significant reduction in complications requiring a return to theatre in the immediate postoperative period. Modern scanners and techniques can reduce the level of ionising radiation, facilitating patients being able to benefit from the advantages that this preoperative planning can convey. PMID:27047777

Opaque bubble layer incidence in Femtosecond laser-assisted LASIK: comparison among different flap design parameters.

PubMed

Mastropasqua, Leonardo; Calienno, Roberta; Lanzini, Manuela; Salgari, Niccolò; De Vecchi, Sergio; Mastropasqua, Rodolfo; Nubile, Mario

2017-06-01

The purpose of this study was to evaluate the incidence of opaque bubble layer (OBL) in femtosecond laser-assisted in situ keratomileusis (LASIK) flaps created with the support of Visumax Carl Zeiss femtosecond laser, planned with different flap diameters (7.90, 8.0, and 8.20 mm) and the same laser energy and power settings. Incidence of intraoperative OBL in flaps of consecutive 108 patients (216 eyes) subjected to bilateral femtosecond-assisted LASIK was considered. Flap creation was performed with the same laser design parameters (spot distance and energy offset) and different presetting diameters of 7.90 mm (72 eyes, group 1), 8 mm (72 eyes, group 2), and 8.20 mm (72 eyes, group 3). The incidence of OBL was considered and its extension was reported measuring involvement of different four corneal flap quadrants in which was theoretically divided the entire flap area; based on these data, OBL presence was classified as none (no evidence of OBL), minimal (minimal presence in not more that one quadrants corneal flap), mild (OBL presence in almost two or three quadrants without tendency to invade central cornea), and moderate (OBL presence in almost three quadrants with tendency to invade central cornea). In group 1, the incidence of OBL was of 23.6 % (17 eyes) with a mild/moderate presence; in group 2, incidence was 20.8 % (15 eyes) with mild presence. Group 3 presented a reduced OBL incidence (4.1 %, 3 eye) with a minimal presence. No statistically significant difference was found between group 1 and 2 (p = 0.8414).We found statistically significant differences between group 1 and group 3 (p = 0.0012) and between groups 2 and 3 (p = 0.0044). A significant reduction and extension of OBL incidence were evident when LASIK flap settings diameter was increased, and flap edge was closer to the contact glass border; this is probably consequent to a more effective gas dispersion outside of corneal flap.

The 'RITE' use of the Fricke flap in periorbital reconstruction.

PubMed

Wilcsek, G; Leatherbarrow, B; Halliwell, M; Francis, I

2005-08-01

To revisit an important but outmoded periorbital reconstructive technique. We present cases to illustrate the usefulness of the Fricke flap and describe a method of rapid intraoperative tissue expansion (RITE), which can enhance the applicability and effectiveness of the Fricke flap. A comparison between those cases performed with and without adjunctive RITE was not made due to the low numbers available. A retrospective review of clinical cases. A total of 20 cases in which the Fricke flap was used for periorbital reconstruction were reviewed. The mean patient age was 64.7 years; the male-to-female ratio was 1:1. The patient follow-up ranged from 1 to 8 years with a mean of 4.2 years. The most common cause (65%) of periorbital defect was excision of eyelid malignancy. Necrosis of the terminal segment of the flap requiring further surgical intervention occurred in 10% (2/20). In both of these cases, the surgeons were trainees, with the complications being due to poor surgical technique. In the first case, the flap base was too narrow and in the second case, the distal end of the flap was thinned excessively. The functional result was excellent in 10/20 (50%), good in 5/20 (25%), fair in 3/20 (15%), and poor in 2/20 (10%). The cosmetic result was excellent in 3/20 (15%), good in 12/20 (60%), fair in 3/20 (15%), and poor in 2/20 (10%). The Fricke flap is an important and, in selected cases, an indispensable technique in periorbital reconstruction.

Effects of magnesium-based hydrogen storage materials on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant.

PubMed

Liu, Leili; Li, Jie; Zhang, Lingyao; Tian, Siyu

2018-01-15

MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 were prepared, and their structure and hydrogen storage properties were determined through X-ray photoelectron spectroscopy and thermal analyzer. The effects of MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant were subsequently studied. Results indicated that MgH 2 , Mg 2 NiH 4 , and Mg 2 CuH 3 can decrease the thermal decomposition peak temperature and increase the total released heat of decomposition. These compounds can improve the effect of thermal decomposition of the propellant. The burning rates of the propellant increased using Mg-based hydrogen storage materials as promoter. The burning rates of the propellant also increased using MgH 2 instead of Al in the propellant, but its explosive heat was not enlarged. Nonetheless, the combustion heat of MgH 2 was higher than that of Al. A possible mechanism was thus proposed. Copyright © 2017. Published by Elsevier B.V.

Outcomes in head and neck reconstruction by surgical site and donor site.

PubMed

Frederick, John W; Sweeny, Larissa; Carroll, William R; Peters, Glenn E; Rosenthal, Eben L

2013-07-01

Define surgical outcomes of specific donor sites for free tissue transfer in head and neck reconstruction. Retrospective cohort review at an academic tertiary care center. A review was made of free tissue transfer procedures performed at a university-based tertiary care facility from October 2004 to April 2011. A total of 1,051 patients underwent six types of free flaps: fasciocutaneous radial forearm (53%), osteocutaneous radial forearm (16%), rectus abdominis (11%), fibula (10%), anterior lateral thigh (7%), and latissimus dorsi (2%). Demographic data were collected, and outcomes measured were: length of hospital stay, flap viability, and major complications (infection, fistula, and hematoma). Of the 1,051 flaps performed, the most common operative site was oral cavity (40%, n = 414) followed by hypopharynx/larynx (22%, n = 234), cutaneous (20%, n = 206), oropharynx (9%, n = 98), midface (7%, n = 76), and skull base (2%, n = 23). The median hospital stay was 7.9 days (range, 1-76), and the overall failure rate was 2.8%. Cutaneous defects required the shortest length of hospitalization (5.8 days, P < .0001), a low free flap failure rate (1.5%, n = 3), and limited major complications (6%, n = 12). Conversely, oropharynx defects were associated with the longest hospitalization (8.9 days). Midface defects had a high incidence of complications (15%, n = 11, P = .10). Defects above the angle of the mandible had higher overall complications when compared to below. Similarly, reconstruction for primary or recurrent cancer had a total failure rate of 2.5%, whereas secondary reconstruction and radionecrosis had a failure rate of 4.0% (P = .29). Additionally, there was no statistical difference between outcomes based on donor site. This review demonstrates that certain subsets of patients are at higher risk for complications after free tissue transfer. Patients undergoing free flap reconstruction for cutaneous defects have substantially shorter hospital stays and are at lower risk of flap complications, whereas reconstruction for radionecrosis and secondary reconstruction tend to have higher overall flap failure rates. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Outcomes in head and neck reconstruction by surgical site and donor site

PubMed Central

Frederick, JW; Sweeny, L; Carroll, WR; Peters, GE; Rosenthal, EL

2012-01-01

Objective Define surgical outcomes of specific donor sites for free tissue transfer in head and neck reconstruction. Design Retrospective cohort review Setting Academic tertiary care center. Patients A review of free tissue transfer procedures performed at a university-based tertiary care facility from October 2004 to April 2011. A total of 1051 patients underwent 6 types of free flaps: fasciocutaneous radial forearm (53%), osteocutaneous radial forearm (16%), rectus abdominus (11%), fibula (10%), anterior lateral thigh (7%), and latissimus dorsi (2%). Main Outcome Measures Demographic data was collected and outcomes measured were: length of hospital stay, flap viability, and major complications (infection, fistula, and hematoma). Results Of the 1051 flaps performed, the most common operative site was oral cavity (40% n=414) followed by hypopharynx/larynx (22%, n=234), cutaneous (20%, n=206), oropharynx (9%, n= 98), mid-face (7%, n= 76), and skull base (2%, n=23). The median hospital stay was 7.9 days (range 1-76) and the overall failure rate was 2.8%. Cutaneous defects required the shortest length of hospitalization (5.8 days, P< .0001), a low free flap failure rate (1.5%, n= 3), and limited major complications (6%, n= 12). Conversely, oropharynx defects were associated with the longest hospitalization (8.9 days). While midface defects had a high incidence of complications (15%, n= 11, P=.10). Defects above the angle of the mandible had higher overall complications when compared to below. Similarly, reconstruction for primary or recurrent cancer had a total failure rate of 2.5% while secondary reconstruction and radionecrosis had a failure rate of 4.0% (P=.29). Additionally, there was no statistical difference between outcomes based on donor site. Conclusions This review demonstrates that certain subsets of patients are at higher risk for complications after free tissue transfer. Patients undergoing free flap reconstruction for cutaneous defects have substantially shorter hospital stays and are at lower risk of flap complications, while reconstruction for radionecrosis or secondary reconstruction tend to have higher overall flap failure rates. PMID:23686870

7. INTERIOR VIEW, SHOWING PROPELLER TEST STAND AND BOMB BAYS. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. INTERIOR VIEW, SHOWING PROPELLER TEST STAND AND BOMB BAYS. - Wright-Patterson Air Force Base, Area B, Building No. 20A, Propeller Test Complex, Seventh Street, from E to G Streets, Dayton, Montgomery County, OH

15. INTERIOR VIEW OF PROPELLER STAND VIEWING ROOM AND SCOPE. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. INTERIOR VIEW OF PROPELLER STAND VIEWING ROOM AND SCOPE. - Wright-Patterson Air Force Base, Area B, Building No. 20A, Propeller Test Complex, Seventh Street, from E to G Streets, Dayton, Montgomery County, OH

5. INTERIOR VIEW, SHOWING PROPELLER TEST STAND AND BOMB BAYS. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. INTERIOR VIEW, SHOWING PROPELLER TEST STAND AND BOMB BAYS. - Wright-Patterson Air Force Base, Area B, Building No. 20A, Propeller Test Complex, Seventh Street, from E to G Streets, Dayton, Montgomery County, OH

Development of surrogate models for the prediction of the flow around an aircraft propeller

NASA Astrophysics Data System (ADS)

Salpigidou, Christina; Misirlis, Dimitris; Vlahostergios, Zinon; Yakinthos, Kyros

2018-05-01

In the present work, the derivation of two surrogate models (SMs) for modelling the flow around a propeller for small aircrafts is presented. Both methodologies use derived functions based on computations with the detailed propeller geometry. The computations were performed using k-ω shear stress transport for modelling turbulence. In the SMs, the modelling of the propeller was performed in a computational domain of disk-like geometry, where source terms were introduced in the momentum equations. In the first SM, the source terms were polynomial functions of swirl and thrust, mainly related to the propeller radius. In the second SM, regression analysis was used to correlate the source terms with the velocity distribution through the propeller. The proposed SMs achieved faster convergence, in relation to the detail model, by providing also results closer to the available operational data. The regression-based model was the most accurate and required less computational time for convergence.

Functional resurfacing of the palm: flap selection based on defect analysis.

PubMed

Engelhardt, T O; Rieger, U M; Schwabegger, A H; Pierer, G

2012-02-01

Extensive defect coverage of the palm and anatomical reconstruction of its unique functional capacity remains difficult. In manual laborers, reconstruction of sensation, range of motion, grip strength but also mechanical stability is required. Sensate musculo-/fasciocutaneous flaps bear disadvantages of tissue mobility with shifting/bulkiness under stress. Thin muscle and fascial flaps show adherence but preclude sensory nerve coaptation. The purpose of this review is to present our algorithm for reliable selection of the most appropriate procedure based on defect analysis. Defect analysis focusing on units of tactile gnosis provides information to weigh needs for sensation or soft tissue stability. We distinguish radial unit (r)-thenar, ulnar unit (u)-hypothenar and unit (c)-central plus distal palm. Individual parameters need similar consideration to choose adequate treatment. Unit (r) and unit (u) are regions of secondary touch demanding protective sensation. Restoration of sensation using neurovascular, fasciocutaneous flaps is recommended. In unit (c), tactile gnosis is of less, mechanical resistance of greater value. Reconstruction of soft tissue resistance is suggested first in this unit. In laborers, free fascial- or muscle flaps with plantar instep skin grafts may achieve near to anatomical reconstruction with minimal sensation. Combined defects involving unit (c) require correlation with individual parameters for optimal flap selection. Defect coverage of the palm should not consist of merely providing sensate vascularized tissue. The most appropriate procedure should be derived from careful defect analysis to achieve near to anatomical reconstruction. In laborers, defect related demands need close correlation with sensation and mechanical stability to be expected. Copyright © 2011 Wiley Periodicals, Inc.

Comparison of Laser Doppler and Laser-Assisted Indocyanine Green Angiography Prediction of Flap Survival in a Novel Modification of the McFarlane Flap.

PubMed

Fourman, Mitchell Stephen; Gersch, Robert P; Phillips, Brett T; Nasser, Ahmed; Rivara, Andrew; Verma, Richa; Dagum, Alexander B; Rosengart, Todd K; Bui, Duc T

2015-07-01

The McFarlane rat ischemic dorsal skin flap model has been commonly used for clinical vector studies, as well as the testing of noninvasive diagnostics. However, variability of this model secondary to flap contact with the wound bed has led many to question its validity. Here we present a novel modification to the McFarlane skin flap using sterile silicone. We also use this model to test the prognostic efficacy of laser-assisted indocyanine green (ICG) angiography and laser Doppler imaging (LDI). A 3 × 9-cm dorsal skin flap with a cranially based pedicle was created, centered 1 cm distal to the scapulae. The flap was undermined, and in one of the 2 groups, a sterile silicone sheet was placed onto the wound bed. All flaps were then reapproximated with sutures 1-cm intervals. Clinical assessment and perfusion imaging was performed immediately postoperative, and at 24, 48, and 72 hours postsurgery. Postoperative day 7 clinical assessment was obtained before euthanasia. A comparative study using silicone blocked versus unblocked models (n = 6 per group) showed that, clinically, both models had equivalent flap survival [8.5 (0.913) vs 9.5 (1.01) cm]. However, a statistically significant increase in perfusion in the mid-third of unblocked models was observed on POD3 [20.28% (2.7%) vs blocked 13.45% (2.5%), P < 0.05], with a similar increase in the distal third on POD7 [18.73% (2.064%) vs 10.91% (4.19%), P < 0.05]. A prognostic study comparing LDI and ICG angiography prediction of POD7 survival at early time points (n = 10) found that LDI underpredicted flap survival at early time points [84.2% (12.03%) on POD0, 87.35% (16.11%) on POD1]. In contrast, ICG was more proficient [100.1% (10.1%) on POD0]. We present a modification of the McFarlane skin flap model that results in similar clinical results, but with a noted reduction in perfusion inconsistencies noted in unblocked models. The ICG angiography is superior to LDI in predicting POD7 flap necrosis within the first 48 hours postinjury. Future work will focus on histologic validation of our model, and vector efficacy testing.

Four-flap Breast Reconstruction: Bilateral Stacked DIEP and PAP Flaps

PubMed Central

Mayo, James L.; Allen, Robert J.

2015-01-01

Background: In cases of bilateral breast reconstruction when the deep inferior epigastric perforator (DIEP) free flap alone does not provide sufficient volume for body-specific reconstruction, stacking each DIEP flap with a second free flap will deliver added volume and maintain a purely autologous reconstruction. Stacking the profunda artery perforator (PAP) flap with the DIEP flap offers favorable aesthetics and ideal operative efficiency. We present the indications, technique, and outcomes of our experience with 4-flap breast reconstruction using stacked DIEP/PAP flaps. Methods: The authors performed 4-flap DIEP/PAP breast reconstruction in 20 patients who required bilateral reconstruction without adequate single donor flap volume. The timing of reconstruction, average mastectomy/flap weights, and operative time are reported. Complications reviewed include fat necrosis, dehiscence, hematoma, seroma, mastectomy flap necrosis, and flap loss. Results: Twenty patients underwent 4-flap DIEP/PAP breast reconstruction. Surgical time averaged 7 hours and 20 minutes. The primary recipient vessels were the antegrade and retrograde internal mammary vessels. No flap losses occurred. Complications included 1 hematoma, 1 incidence of arterial and venous thrombosis successfully treated with anastomotic revision, 1 incidence of thigh donor site dehiscence, and 3 episodes of minor mastectomy skin flap necrosis. Conclusions: Four-flap breast reconstruction is a favorable autologous reconstructive option for patients requiring bilateral reconstruction without adequate single donor flap volume. Stacking DIEP/PAP flaps as described is both safe and efficient. Furthermore, this combination provides superior aesthetics mirroring the natural geometry of the breast. Bilateral stacked DIEP/PAP flaps represent our first choice for breast reconstruction in this patient population. PMID:26090273

Free Boomerang-shaped Extended Rectus Abdominis Myocutaneous flap: The longest possible skin/myocutaneous free flap for soft tissue reconstruction of extremities.

PubMed

Koul, Ashok R; Nahar, Sushil; Prabhu, Jagdish; Kale, Subhash M; Kumar, Praveen H P

2011-09-01

A soft tissue defect requiring flap cover which is longer than that provided by the conventional "long" free flaps like latissimus dorsi (LD) and anterolateral thigh (ALT) flap is a challenging problem. Often, in such a situation, a combination of flaps is required. Over the last 3 years, we have managed nine such defects successfully with a free "Boomerang-shaped" Extended Rectus Abdominis Myocutaneous (BERAM) flap. This flap is the slightly modified and "free" version of a similar flap described by Ian Taylor in 1983. This is a retrospective study of patients who underwent free BERAM flap reconstruction of soft tissue defects of extremity over the last 3 years. We also did a clinical study on 30 volunteers to compare the length of flap available using our design of BERAM flap with the maximum available flap length of LD and ALT flaps, using standard markings. Our clinical experience of nine cases combined with the results of our clinical study has confirmed that our design of BERAM flap consistently provides a flap length which is 32.6% longer than the standard LD flap and 42.2% longer than the standard ALT flap in adults. The difference is even more marked in children. The BERAM flap is consistently reliable as long as the distal end is not extended beyond the mid-axillary line. BERAM flap is simple in design, easy to harvest, reliable and provides the longest possible free skin/myocutaneous flap in the body. It is a useful new alternative for covering long soft tissue defects in the limbs.

The Shuttle Orbital Maneuvering System P-V-T Propellant Quantity Gaging Accuracy and Leak Detection Allowance for Four Instrumentation Conditions

NASA Technical Reports Server (NTRS)

Duhon, D. D.

1975-01-01

The shuttle orbital maneuvering system (OMS) pressure-volume-temperature (P-V-T) propellant gaging module computes the quantity of usable OMS propellant remaining based on the real gas P-V-T relationship for the propellant tank pressurant, helium. The OMS P-V-T propellant quantity gaging error was determined for four sets of instrumentation configurations and accuracies with the propellant tank operating in the normal constant pressure mode and in the blowdown mode. The instrumentation inaccuracy allowance for propellant leak detection was also computed for these same four sets of instrumentation. These gaging errors and leak detection allowances are presented in tables designed to permit a direct comparison of the effectiveness of the four instrumentation sets. The results show the magnitudes of the improvements in propellant quantity gaging accuracies and propellant leak detection allowances which can be achieved by employing more accurate pressure and temperature instrumentation.

[Preoperative CT angiography for planning free perforator flaps in breast reconstruction].

PubMed

Kuekrek, H; Müller, D; Paepke, S; Dobritz, M; Machens, H-G; Giunta, R E

2011-04-01

Preoperative Doppler ultrasonography for planning free perforator flaps is widely established to identify preoperatively perforators. The method allows one to localise the penetrating point of the perforator through the abdominal fascia. By this means it is not possible to see the intramuscular course or the position of the perforator in relation to the inferior epigastric artery. Lately the technique of computed tomographic angiography provides an opportunity for visualising the course of perforator vessels in these tissues. This paper summarises our experience with the preoperative CT angiography in our breast centre. Since spring 2009 we have reconstructed the breasts of 44 female patients by using free flaps from the lower abdominal wall. 6 of these were bilateral. In a total number of 50 breast reconstructions we used 23 deep inferior epigastric perforator (DIEP) flaps and 27 muscle-sparing transverse rectus abdominis muscle (TRAM) flaps. In addition to the preoperative ultrasonography, a CT angiography of the lower abdomen was conducted in 29 patients. On average they showed at least 2 perforators on the left as well as right abdominal sides, which could be used as flap vessels based on their signal intensity. Based on their estimated microsurgical dissection complexity, the perforator vessels could be classified into 3 groups: 1) direct perforators of category A with short intramuscular course (39%), 2) perforators with long intramuscular course of category B (50%) and 3) "turn around" perforators of category C, which pass medially around the rectus abdominis (11%). The technique of CT angiography permits a reliable preoperative visualisation of perforators in their entire course and facilitates the selection of the supplying perforator as well as the intraoperative procedure for the surgeon. The suggested classification of perforators into 3 groups simplifies the preoperative assessment of the microsurgical dissection effort. Compared to the commonly used Doppler ultrasonography there are disadvantages like the additional cost factor and the radiation exposure. However, in our experience the more detailed planning increases the safety of flap raising and reduces surgery time, so that we consider CT angiography a positive tool to facilitate free perforator flaps. © Georg Thieme Verlag KG Stuttgart · New York.

Mars Ascent Vehicle-Propellant Aging

NASA Technical Reports Server (NTRS)

Dankanich, John; Rousseau, Jeremy; Williams, Jacob

2015-01-01

This project is to develop and test a new propellant formulation specifically for the Mars Ascent Vehicle (MAV) for the robotic Mars Sample Return mission. The project was initiated under the Planetary Sciences Division In-Space Propulsion Technology (ISPT) program and is continuing under the Mars Exploration Program. The two-stage, solid motor-based MAV has been the leading MAV solution for more than a decade. Additional studies show promise for alternative technologies including hybrid and bipropellant options, but the solid motor design has significant propellant density advantages well suited for physical constraints imposed while using the SkyCrane descent stage. The solid motor concept has lower specific impulse (Isp) than alternatives, but if the first stage and payload remain sufficiently small, the two-stage solid MAV represents a potential low risk approach to meet the mission needs. As the need date for the MAV slips, opportunities exist to advance technology with high on-ramp potential. The baseline propellant for the MAV is currently the carboxyl terminated polybutadiene (CTPB) based formulation TP-H-3062 due to its advantageous low temperature mechanical properties and flight heritage. However, the flight heritage is limited and outside the environments, the MAV must endure. The ISPT program competed a propellant formulation project with industry and selected ATK to develop a new propellant formulation specifically for the MAV application. Working with ATK, a large number of propellant formulations were assessed to either increase performance of a CTPB propellant or improve the low temperature mechanical properties of a hydroxyl terminated polybutadiene (HTPB) propellant. Both propellants demonstrated potential to increase performance over heritage options, but an HTPB propellant formulation, TP-H-3544, was selected for production and testing. The test plan includes propellant aging first at high vacuum conditions, representative of the Mars transit, followed by an additional year at simulated Mars surface conditions. The actual Mars surface environment is based on the igloo design, actively maintains the propellant at or above -40 degC, 95% carbon dioxide at Mars surface pressure. The NASA Marshall Space Flight Center (MSFC) Mars environment test facility is shown in figure 1 and located in the East Test area of Redstone Arsenal due to storage of live propellants. The facility consists of a vacuum chamber placed inside a large freezer unit. The facility includes pressure and temperature monitoring equipment in addition to a vacuum quality monitoring system spectrometer to record any outgassing products.

Free Boomerang-shaped Extended Rectus Abdominis Myocutaneous flap: The longest possible skin/myocutaneous free flap for soft tissue reconstruction of extremities

PubMed Central

Koul, Ashok R.; Nahar, Sushil; Prabhu, Jagdish; Kale, Subhash M.; Kumar, Praveen H. P.

2011-01-01

Background: A soft tissue defect requiring flap cover which is longer than that provided by the conventional “long” free flaps like latissimus dorsi (LD) and anterolateral thigh (ALT) flap is a challenging problem. Often, in such a situation, a combination of flaps is required. Over the last 3 years, we have managed nine such defects successfully with a free “Boomerang-shaped” Extended Rectus Abdominis Myocutaneous (BERAM) flap. This flap is the slightly modified and “free” version of a similar flap described by Ian Taylor in 1983. Materials and Methods: This is a retrospective study of patients who underwent free BERAM flap reconstruction of soft tissue defects of extremity over the last 3 years. We also did a clinical study on 30 volunteers to compare the length of flap available using our design of BERAM flap with the maximum available flap length of LD and ALT flaps, using standard markings. Results: Our clinical experience of nine cases combined with the results of our clinical study has confirmed that our design of BERAM flap consistently provides a flap length which is 32.6% longer than the standard LD flap and 42.2% longer than the standard ALT flap in adults. The difference is even more marked in children. The BERAM flap is consistently reliable as long as the distal end is not extended beyond the mid-axillary line. Conclusion: BERAM flap is simple in design, easy to harvest, reliable and provides the longest possible free skin/myocutaneous flap in the body. It is a useful new alternative for covering long soft tissue defects in the limbs. PMID:22279271

Umbilical necrosis rates after abdominal-based microsurgical breast reconstruction.

PubMed

Ricci, Joseph A; Kamali, Parisa; Becherer, Babette E; Curiel, Daniel; Wu, Winona; Tobias, Adam M; Lin, Samuel J; Lee, Bernard T

2017-07-01

Umbilical stalk necrosis represents a rare, yet important complication after abdominal-based microsurgical breast reconstruction, which is both underrecognized and understudied in the literature. Once identified, umbilical reconstruction can be an extremely challenging problem. All consecutive breast free flaps at a single institution from February 2004 to February 2016 were reviewed, excluding non-abdominal-based flaps. Patients were divided based on the development of umbilical necrosis postoperatively. Demographics, surgical characteristics, and other complications were compared between the groups. A total of 918 patients met the inclusion criteria, with 29 developing umbilical necrosis identified (3.2%). Patients developing necrosis tended to be older (49.4 yrs versus 52.9 yrs; P < 0.01); have higher BMI (31.3 versus 27.8; P < 0.01); and were more likely to be smokers (27.5% versus 11.6%; P = 0.01). Umbilical necrosis was also associated with increased flap weight (830 g versus 656 g; P < 0.01), decreased time of perforator dissection (151 min versus 169 min; P = 0.02); bilateral cases (68.9% versus 44.7%; P < 0.01), and increased number of perforators per flap (2.5 versus 2.2; P = 0.03). There was no association with flap type (deep inferior epigastric perforator, superficial inferior epigastric artery, or free TRAM), diabetes, previous abdominal surgery, or use of preoperative imaging. Umbilical necrosis was not associated with any concomitant complications. Umbilical stalk necrosis was found to occur in 3.2% of patients and was associated with several preoperative comorbidities and intraoperative characteristics. This information should help influence intraoperative decision-making to prevent the development of this undesirable complication. Copyright © 2017 Elsevier Inc. All rights reserved.

The possibility for use of venous flaps in plastic surgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baytinger, V. F., E-mail: baitinger@mail.tomsknet.ru; Kurochkina, O. S., E-mail: kurochkinaos@yandex.ru; Selianinov, K. V.

2015-11-17

The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were nomore » differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.« less

Conceptual design of flapping-wing micro air vehicles.

PubMed

Whitney, J P; Wood, R J

2012-09-01

Traditional micro air vehicles (MAVs) are miniature versions of full-scale aircraft from which their design principles closely follow. The first step in aircraft design is the development of a conceptual design, where basic specifications and vehicle size are established. Conceptual design methods do not rely on specific knowledge of the propulsion system, vehicle layout and subsystems; these details are addressed later in the design process. Non-traditional MAV designs based on birds or insects are less common and without well-established conceptual design methods. This paper presents a conceptual design process for hovering flapping-wing vehicles. An energy-based accounting of propulsion and aerodynamics is combined with a one degree-of-freedom dynamic flapping model. Important results include simple analytical expressions for flight endurance and range, predictions for maximum feasible wing size and body mass, and critical design space restrictions resulting from finite wing inertia. A new figure-of-merit for wing structural-inertial efficiency is proposed and used to quantify the performance of real and artificial insect wings. The impact of these results on future flapping-wing MAV designs is discussed in detail.

New insights into insect's silent flight. Part II: sound source and noise control

NASA Astrophysics Data System (ADS)

Xue, Qian; Geng, Biao; Zheng, Xudong; Liu, Geng; Dong, Haibo

2016-11-01

The flapping flight of aerial animals has excellent aerodynamic performance but meanwhile generates low noise. In this study, the unsteady flow and acoustic characteristics of the flapping wing are numerically investigated for three-dimensional (3D) models of Tibicen linnei cicada at free forward flight conditions. Single cicada wing is modelled as a membrane with prescribed motion reconstructed by Wan et al. (2015). The flow field and acoustic field around the flapping wing are solved with immersed-boundary-method based incompressible flow solver and linearized-perturbed-compressible-equations based acoustic solver. The 3D simulation allows examination of both directivity and frequency composition of the produced sound in a full space. The mechanism of sound generation of flapping wing is analyzed through correlations between acoustic signals and flow features. Along with a flexible wing model, a rigid wing model is also simulated. The results from these two cases will be compared to investigate the effects of wing flexibility on sound generation. This study is supported by NSF CBET-1313217 and AFOSR FA9550-12-1-0071.

Novel method for measuring a dense 3D strain map of robotic flapping wings

NASA Astrophysics Data System (ADS)

Li, Beiwen; Zhang, Song

2018-04-01

Measuring dense 3D strain maps of the inextensible membranous flapping wings of robots is of vital importance to the field of bio-inspired engineering. Conventional high-speed 3D videography methods typically reconstruct the wing geometries through measuring sparse points with fiducial markers, and thus cannot obtain the full-field mechanics of the wings in detail. In this research, we propose a novel system to measure a dense strain map of inextensible membranous flapping wings by developing a superfast 3D imaging system and a computational framework for strain analysis. Specifically, first we developed a 5000 Hz 3D imaging system based on the digital fringe projection technique using the defocused binary patterns to precisely measure the dynamic 3D geometries of rapidly flapping wings. Then, we developed a geometry-based algorithm to perform point tracking on the precisely measured 3D surface data. Finally, we developed a dense strain computational method using the Kirchhoff-Love shell theory. Experiments demonstrate that our method can effectively perform point tracking and measure a highly dense strain map of the wings without many fiducial markers.