Flying Qualities of Otto Lilienthal's Large Biplane

The paper describes full-scale balance tests, which have proven structural integrity and longitudinal static stability of an authentic replica of Otto Lilienthal's Large Biplane glider. In addition to that, the replica, built after patent drawings, photographs, and textual descriptions by the Otto-Lilienthal-Museum, was towed using a rope winch and finally flown downhill without rope or guide wires. The tests allow for the assessment of the aircraft's controllability and stability not only during steady flight, but also during takeoff, landing, and on the occasion of wind gusts. A brief description of the design parameters and applied methods is given along with force and moment data gained from balance measurements as well as the evaluation of a limited set of data acquired during flight, including speed, duration, and distances flown

Flight testing Otto Lilienthal's experimental monoplane

Free flights and tethered flights were performed using an authentic replica of Otto Lilienthal's experimental monoplane, the "Vorflügelapparat", achieving flight distances of more than 100m. The flight stability, controllability and performance of the design has been verified through balance measurements using a 1:5 scaled wind tunnel test

Über die Flugeigenschaften von Otto Lilienthals großem Doppeldecker

Der Artikel beschreibt aerodynamische Messungen, die die strukturelle und die statische Längsstabilität eines authentischen Nachbaus von Otto Lilienthals großem Doppeldecker nachweisen. Darüber hinaus wurde der nach Patentzeichnungen, Fotos und Textbeschreibungen vom Otto-Lilienthal-Museum gebaute Nachbau des historischen Gleiters mit einer Seilwinde geschleppt und schließlich, ganz ohne Seile, bergab geflogen. Die Tests ermöglichen die Beurteilung der Steuerbarkeit und Stabilität des Flugzeugs nicht nur im stationären Flug, sondern auch bei Start, Landung und bei Windböen. Eine kurze Beschreibung der Konstruktionsparameter und der angewandten Methoden wird ebenso beschrieben wie die Auswertungen Kraft- und Momentdaten, die aus Waagenmessungen gewonnen wurden. Dargestellt wird darüber hinaus die Auswertung eines begrenzten Satzes von Daten, die während des Fluges gewonnen wurden, einschließlich Geschwindigkeit, Dauer und geflogene Distanzen

Leiomyosarcoma of the inferior vena cava: Radical surgery and vascular reconstruction

<p>Abstract</p> <p>Background</p> <p>Vascular leiomyosarcoma are rare tumors typically originating from the inferior vena cava (IVC). Due to nonspecific clinical signs most tumors are diagnosed at advanced stages. Complete surgical resection remains the only potential curative therapeutic option. Surgical strategy is particularly influenced by the level of the IVC affected. Due to the topographic relation to the renal veins level-II involvement of the IVC raises special surgical challenges with respect to the maintenance of venous outflow.</p> <p>Case presentation</p> <p>We herein report two cases of leiomyosarcoma of the IVC with successful en bloc resection and individualized caval reconstruction. One patient presented with a large intramural and intraluminal mass and received a complete circumferential resection. Reconstruction was performed by graft replacement of the caval segment affected. The other patient displayed a predominantly extraluminal tumor growth and underwent semicircumferential resection of the IVC including the confluence of the left renal vein. In this case vascular reconstruction was performed by cavoplasty and reinsertion of the left renal vein into the proximal portion of the IVC. Resection margins of both patients were tumor free and no clinical signs of venous insufficiency of the lower extremity occurred.</p> <p>Conclusion</p> <p>This paper presents two cases of successfully managed leiomyosarcomas of the vena cava and exemplifies two different options for vascular reconstruction in level II sarcomas and includes a thorough review of the literature.</p

Flight Controls of Otto Lilienthal's Experimental Monoplane from 1895

In 1889, Otto Lilienthal published his book Birdflight as the Basis of Aviation, containing the first lift-versus-drag data of cambered wings and other important information required for human flight. In 1895, Lilienthal demonstrated his 12th aircraft design, a monoplane with a wing area of over 20 m2. Because of its wingspan of almost 9 m and wing chord length of 3 m, Lilienthal’s largest monoplane can only be used in light winds. Lilienthal applied for a patent on the same day. The patent claim was submitted for the front wing (Vorflügel), a leading-edge flap used in a glider for this purpose for the first time. Because of the size of the apparatus, three profile rails were slid onto each wing instead of the usual two

Recurrent Fistula between Ileal Pouch and Vagina—Successful Treatment with a Gracilis Muscle Flap

Fistulae between an ileal pouch and the vagina are an uncommon complication of ileal pouch-anal anastomosis following proctocolectomy and mucosectomy in patients with familial adenomatous polyposis coli. Several reports describe the successful use of muscle flaps to close recurrent pouch-vaginal-fistulae (PVF). However, series only contain small numbers and an optimal management has not yet been determined. We report the case of a 26-year old woman with a third recurrence of a PVF after proctocolectomy for treatment of familial adenomatous polyposis in October 2005. Because local approaches failed, definitive closure of the fistula was achieved by interposition of a gracilis muscle flap between the pouch-anal anastomosis and the vagina. The postoperative course was uneventful; the patient was discharged 7 days after surgery and remained free of recurrence and symptomatic complaints for 22 months now. The gracilis muscle flap proved to be an effective method in the treatment of recurrent PVF

Windkanal- und Flugversuche mit Otto Lilienthal's Experimentiergerät von 1895

1895 patentierte, baute und flog Otto Lilienthal ein Forschungsflugzeug, das mit Steuerflächen ausgestattet war, die vom Piloten betätigt wurden. Es verfügte über gummibandbetätigte Vorderkantenklappen für die automatische Nicksteuerung, sowie über Spoiler, Flügelverwindung und Ruder für die Gier- und Rollsteuerung, die durch eine Hüftgabel betätigt wurden. Für die hier beschriebenen Untersuchungen wurden ein maßstabsgetreuer Nachbau und ein 1:5 Modell gebaut. Alle Strukturmaterialien, die für die Flugeigenschaften relevant sind, wurden mit großer Sorgfalt ausgewählt. Das 1:5-Modell wurde in zwei verschiedenen Windkanälen am Institut für Aerodynamik und Strömungstechnik des Deutschen Zentrums für Luft- und Raumfahrt (DLR) in Göttingen getestet. Der maßstabsgetreue Nachbau wurde für eine Reihe von Fesselflugtests auf den Outer Banks (NC) in Zusammenarbeit mit der Drachenflugschule Kitty Hawk Kites eingesetzt. Die Windkanaltests lieferten neue Erkenntnisse über die Leistung, den Trimmzustand, die Flugstabilität und die Steuerbarkeit. Nach der gängigen Klassifizierung von Lilienthals Segelflugzeugen hat das "Experimentiergerät" eine Spannweite von 8,8m und eine Flügelfläche von 23m2. Lilienthal schrieb, dass diese größeren Abmessungen im Vergleich zu seinen früheren Entwürfen zu besseren Leistungen bei niedrigen Windgeschwindigkeiten führten, aber zusätzliche Steuermittel erforderten, da seine Methode der Gewichtsverlagerung nur begrenzte Steuermöglichkeiten für Flügelspannweiten von mehr als 7 m bot. Es wurden Windkanalmessungen und eine begrenzte Anzahl von Flugtests durchgeführt, um zu untersuchen, ob die patentierte automatische Nicksteuerung und die Steuerflächen ausreichend waren, um das Flugzeug sicher zu steuern

Experimental investigation of the vortical activity in the close wake of a simplified military transport aircraft

This paper focuses on the experimental characterization of the vortex structures that develop in the aft fuselage region and in the wake of a simplified geometry of a military transport aircraft. It comes within the framework of the military applications of airflow influence on airdrop operations. This work relies on particle image velocimetry measurements combined with a vortex-tracking approach. Complex vortex dynamics is revealed, in terms of vortex positions, intensities, sizes, shapes and fluctuation levels, for both closed and opened cargo-door and ramp airdrop configurations

Reduced hematopoietic stem cell frequency predicts outcome in acute myeloid leukemia

In patients with acute myeloid leukemia and low percentages of aldehyde-dehydrogenase-positive cells, non-leukemic hematopoietic stem cells can be separated from leukemic cells. By relating hematopoietic stem cell frequencies to outcome we detected poor overall- and disease-free survival of patients with low hematopoietic stem cell frequencies. Serial analysis of matched diagnostic and follow-up samples further demonstrated that hematopoietic stem cells increased after chemotherapy in patients who achieved durable remissions. However, in patients who eventually relapsed, hematopoietic stem cell numbers decreased dramatically at the time of molecular relapse demonstrating that hematopoietic stem cell levels represent an indirect marker of minimal residual disease, which heralds leukemic relapse. Upon transplantation in immune-deficient mice cases with low percentages of hematopoietic stem cells of our cohort gave rise to leukemic or no engraftment, whereas cases with normal hematopoietic stem cell levels mostly resulted in multi-lineage engraftment. Based on our experimental data, we propose that leukemic stem cells have increased niche affinity in cases with low percentages of hematopoietic stem cells. To validate this hypothesis, we developed new mathematical models describing the dynamics of healthy and leukemic cells under different regulatory scenarios. These models suggest that the mechanism leading to decreases in hematopoietic stem cell frequencies before leukemic relapse must be based on expansion of leukemic stem cells with high niche affinity and the ability to dislodge hematopoietic stem cells. Thus, our data suggest that decreasing numbers of hematopoietic stem cells indicate leukemic stem cell persistence and the emergence of leukemic relapse

General condition and comorbidity of long-term survivors of adult acute lymphoblastic leukemia

Cure rates in adult acute lymphoblastic leukemia (ALL) improved using pediatric-based chemotherapy and stem cell transplantation (SCT). However, limited data on the health condition of cured adults are available whereas pediatric data cannot be transferred. The GMALL analyzed the health status in survivors of adult ALL retrospectively. Physicians answered a questionnaire on general condition (Eastern Cooperative Oncology Group [ECOG] status) and comorbidity or syndrome occurrence observed after treatment. Five hundred and thirty-eight patients with a median age of 29 (range, 15-64) years at diagnosis were analyzed, median follow-up was 7 (range, 3-24) years. Thirty-one percent had received SCT. ECOG status was 0-1 in 94%, 34% had not developed significant comorbidities. Most frequent comorbidities involved the neurologic system (27%), endocrine system (20%), skin (18%), graft-versus-host-disease (15%), cardiac system (13%), fatigue (13%). SCT impacted ECOG status and comorbidity occurrence significantly. ECOG 0-1 was observed in 86% of SCT and 98% of non-SCT patients (P<0.0001); comorbidity was observed in 87% and 57% respectively (P<0.0001). Our analysis elucidates the spectrum of comorbidities in cured adult ALL patients, with higher risk for transplanted patients, providing stimulations for the design of adequate aftercare programs. Overall, a large proportion of non-SCT patients achieved unrestricted general condition. The data provide a reference for new patient-centered endpoints in future trials