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An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass-flow rate, due to either their ingestion or evacuation by the nozzle. This in turn caused a downstream acoustic response. For low-intensity background swirl the responses were found to be similar to those obtained without steady background swirl. Perturbations of a high-intensity background swirl led to different effects. For long injection times, the negative mass-flow rate modulation occurred in two stages. The first stage was similar to that of the background-swirl free case. The second stage occurred after a short time delay, and induced a much stronger negative acoustic response. This unexpected behavior suggests that a significant part of the tangentially injected fluid flows upstream inducing an accumulation of swirl, which is – after tangential injection is ceased – suddenly cleared out through the nozzle. A scaling rule for the amplitudes of these acoustic responses is reported. Furthermore, quasi-steady models, based on steady-state measurements are proposed. These models predict the downstream acoustic response amplitude within a factor two. Additionally, preliminary empirical evidence of the effect of swirl on the downstream acoustic response due to the interaction of entropy patches with a choked nozzle is reported. This was obtained by comparison of sound produced by abrupt radial or tangential sonic injection, upstream from the choked nozzle, of air from a reservoir at room temperature to that from a reservoir with a higher stagnation temperature. Because the mass flow through the nozzle does not increase instantaneously, the injected higher-enthalpy air accumulates upstream of the injection-port position in th, Aerodynamics

An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass-flow rate, due to either their ingestion or evacuation by the nozzle. This in turn caused a downstream acoustic response. For low-intensity background swirl the responses were found to be similar to those obtained without steady background swirl. Perturbations of a high-intensity background swirl led to different effects. For long injection times, the negative mass-flow rate modulation occurred in two stages. The first stage was similar to that of the background-swirl free case. The second stage occurred after a short time delay, and induced a much stronger negative acoustic response. This unexpected behavior suggests that a significant part of the tangentially injected fluid flows upstream inducing an accumulation of swirl, which is – after tangential injection is ceased – suddenly cleared out through the nozzle. A scaling rule for the amplitudes of these acoustic responses is reported. Furthermore, quasi-steady models, based on steady-state measurements are proposed. These models predict the downstream acoustic response amplitude within a factor two. Additionally, preliminary empirical evidence of the effect of swirl on the downstream acoustic response due to the interaction of entropy patches with a choked nozzle is reported. This was obtained by comparison of sound produced by abrupt radial or tangential sonic injection, upstream from the choked nozzle, of air from a reservoir at room temperature to that from a reservoir with a higher stagnation temperature. Because the mass flow through the nozzle does not increase instantaneously, the injected higher-enthalpy air accumulates upstream of the injection-port position in th

An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass-flow rate, due to either their ingestion or evacuation by the nozzle. This in turn caused a downstream acoustic response. For low-intensity background swirl the responses were found to be similar to those obtained without steady background swirl. Perturbations of a high-intensity background swirl led to different effects. For long injection times, the negative mass-flow rate modulation occurred in two stages. The first stage was similar to that of the background-swirl free case. The second stage occurred after a short time delay, and induced a much stronger negative acoustic response. This unexpected behavior suggests that a significant part of the tangentially injected fluid flows upstream inducing an accumulation of swirl, which is – after tangential injection is ceased – suddenly cleared out through the nozzle. A scaling rule for the amplitudes of these acoustic responses is reported. Furthermore, quasi-steady models, based on steady-state measurements are proposed. These models predict the downstream acoustic response amplitude within a factor two. Additionally, preliminary empirical evidence of the effect of swirl on the downstream acoustic response due to the interaction of entropy patches with a choked nozzle is reported. This was obtained by comparison of sound produced by abrupt radial or tangential sonic injection, upstream from the choked nozzle, of air from a reservoir at room temperature to that from a reservoir with a higher stagnation temperature. Because the mass flow through the nozzle does not increase instantaneously, the injected higher-enthalpy air accumulates upstream of the injection-port position in th, Aerodynamics

Background: Evaluation of quality of life following surgical release of the first annular flexor tendon pulley in children suffering from pediatric trigger thumb in comparison to adult patients with trigger finger.Material and methods: All patients who underwent an A1 tendon pulley release between 2006 and 2010 at a hand surgery center were reviewed retrospectively. Chart review included operation type, length of hospital stay, and type of anesthesia. Patient satisfaction was assessed using two validated hand questionnaires, the Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Measure and the German Michigan Hand Outcomes Questionnaire (MHQ).Results: A total of 13 children and 147 adults were included in the study. No postoperative complications or recurrence were observed in the pediatric patient population. Postoperative DASH score in children was 0±0 and in adults 14±2. Postoperative German MHQ score was 97±3 in children and 84±2 in adults. Patient satisfaction was rated positive in all children and in 87% of adults; all children and 93% of the adults would undergo this procedure again. Conclusions: The surgical release of the A1 pulley in children and adults is a safe and low-risk procedure. Postoperative quality of life, especially in children, is high; patients and parents were highly satisfied. Therefore, the surgical approach should be recommended as a first-line treatment of the trigger finger in all age groups., Hintergrund: Evaluation der Lebensqualität nach chirurgischer Ringbandspaltung bei angeborener Ringbandstenose des Daumens bei Kindern (Pollex flexus congenitus) sowie erworbener Ringbandstenose bei Erwachsenen. Material und Methoden: Retrospektiv wurden allgemeine Patientendaten nach offener Ringbandspaltung zwischen 2006 und 2010 sowie die Patientenzufriedenheit mit den Patienten-orientierten Fragebögen Michigan Hand Outcomes Questionnaire (MHQ) und Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Measure ausgewertet und analysiert. Ergebnisse: 13 Kinder und 147 erwachsene Patienten wurden in die Studie aufgenommen. Postoperativ kam es bei den Kindern zu keinen Komplikationen oder dem Wiederauftreten eines Schnappphänomens des Daumens. Der postoperative DASH-Score der Kinder war 0±0 Punkte und bei den Erwachsenen 14±2. Der postoperative MHQ-Score lag bei den Kindern bei 97±3 Punkten, der der Erwachsenen bei 84±2. Die postoperative Zufriedenheit wurde bei allen Kindern und bei 87% der erwachsenen Patienten als positiv gewertet. Alle Kinder sowie 93% der Erwachsenen würden sich erneut diesem operativen Eingriff unterziehen. Schlussfolgerung: Die chirurgische Intervention zur Behandlung des Pollex flexus congenitus bei Kindern sowie der Ringbandstenose bei Erwachsenen ist ein sicherer und risikoarmer Eingriff. Die postoperative Lebensqualität, speziell die der Kinder, ist hoch. Daher kann das chirurgische Vorgehen als First-Line-Therapie beim schnellenden Finger in allen Altersgruppen empfohlen werden.

Background: Evaluation of the quality of life following surgical release of the first extensor compartment in adult patients with de Quervain disease. Patients and methods: This retrospective study included hospital chart review and patient-reported outcome assessment using the German version of the Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Measure and the validated German Michigan Hand Outcomes Questionnaire (MHQ). Results: A total of 46 patients underwent a surgical release of the first extensor compartment for de Quervain disease. Postoperative German MHQ was 78±4. Postoperative DASH score was 19±5. Satisfaction with surgery was rated positive in 85%, and 89% would undergo the procedure again. Patients with a transversal incision line had a DASH result of 11±6 and a German MHQ score of 83±7, patients with a longitudinal incision had a DASH score of 22±9 and a German MHQ score of 80±6. The patients pain level after transversal incision was markedly lower (resting pain=0.4±0.3; stress pain=1.0±0.6) than in patients operated with a longitudinal incision (resting pain=2.4±0.9; stress pain=3.1±1.1). Conclusion: The surgical approach for the treatment of de Quervain disease is associated with a high postoperative quality of life, a low postoperative morbidity and a low level of postoperative pain. A transversal incision is associated with better postoperative results than the longitudinal approach., Hintergrund: Die Zufriedenheit von Patienten nach chirurgischer Spaltung des ersten Strecksehnenfaches bei De Quervain Tendinopathie ist unbekannt. Aufgrund der weiten Verbreitung dieser ambulanten Operation stellten wir uns die Frage, wie sich die Lebensqualität nach offen chirurgischer Spaltung des ersten Strecksehnenfaches bei erwachsenen Patienten mit einer Tendovaginitis stenosans de Quervain verhält. Patienten und Methoden: Retrospektiv wurden Patientendaten sowie die Patienten-orientierten Fragebögen Michigan Hand Outcomes Questionnaire (MHQ) und Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Measure ausgewertet und analysiert. Primäre Endpunkte: DASH-Ergebnis (0=keine Einschränkung, 100=maximale Einschränkung) und MHQ-Ergebnis (0=maximale Einschränkung, 100=keine Einschränkung), sekundäre Endpunkte: Schmerzen (Numerische Rating Skala (NRS) 0-10), Zufriedenheit, Narkoseform, Schnittführung, Komplikationen. Ergebnisse: Wir führten bei insgesamt 46 Patienten eine offen chirurgische Spaltung des ersten Strecksehnenfachs durch. Der postoperative MHQ-Score war 78±4 Punkte und der postoperative DASH-Score 19±5 Punkte. Die Zufriedenheit der Patienten mit dem chirurgischen Vorgehen lag bei 85%, wobei sich 89% dieser Prozedur erneut unterziehen würden. Patienten mit einer quer zum Handgelenk verlaufenden Hautschnittführung hatten einen MHQ-Score von 83±7 Punkten und einen DASH-Score von 11±6 Punkten, während Patienten mit einer Längsinzision einen MHQ-Score von 80±6 Punkten und einen DASH-Score von 22±9 Punkten aufwiesen (n.s.). Das Schmerzniveau nach querer Schnittführung (Ruheschmerz=0,4±0,3; Belastungsschmerz= 1,0±0,6) war deutlich geringer als bei Patienten mit longitudinaler Inzision (Ruheschmerz=2,4±0,9; Belastungsschmerz=3,1±1,1, n.s.). Schlussfolgerung: Die offen chirurgische Spaltung des ersten Strecksehnenfaches bei Tendovaginitis de Quervain ist mit einer hohen postoperativen Lebensqualität, einer geringen Morbidität sowie einem niedrigen Grad an

Contains fulltext : 137748pub.pdf (publisher's version ) (Closed access), Criteria for the diagnosis of serrated colorectal lesions (hyperplastic polyp, sessile serrated adenoma without or with dysplasia-which we called mixed polyp-and traditional serrated adenoma) for which consensus has been reached should be validated for applicability in daily practice in terms of inter-observer reproducibility and their association with clinical features and (epi)genetic events. A study set was created from a consecutive series of colorectal polyps (n = 1,926) by selecting all sessile serrated adenomas, traditional serrated adenomas and mixed polyps. We added consecutive series of hyperplastic polyps, classical adenomas and normal mucosa samples for a total of 200 specimens. With this series, we conducted an inter-observer study, encompassing ten pathologists with gastrointestinal pathology experience from five European countries, in three rounds in which all cases were microscopically evaluated. An assessment of single morphological criteria was included, and these were correlated with clinical parameters and the mutation status of KRAS, BRAF and PIK3CA and the methylation status of MLH1. Gender, age and localisation were significantly associated with certain types of lesions. Kappa statistics revealed moderate to good inter-observer agreement for polyp classification (kappa = 0.56 to 0.63), but for single criteria, this varied considerably (kappa = 0.06 to 0.82). BRAF mutations were frequently found in hyperplastic polyps (86 %, 62/72) and sessile serrated adenomas (80 %, 41/51). KRAS mutations occurred more frequently in traditional serrated adenomas (78 %, 7/9) and less so in classical adenomas (20 %, 10/51). Single morphological criteria for sessile serrated adenomas showed significant correlation with BRAF mutation (all p

Contains fulltext : 137748pub.pdf (publisher's version ) (Closed access), Criteria for the diagnosis of serrated colorectal lesions (hyperplastic polyp, sessile serrated adenoma without or with dysplasia-which we called mixed polyp-and traditional serrated adenoma) for which consensus has been reached should be validated for applicability in daily practice in terms of inter-observer reproducibility and their association with clinical features and (epi)genetic events. A study set was created from a consecutive series of colorectal polyps (n = 1,926) by selecting all sessile serrated adenomas, traditional serrated adenomas and mixed polyps. We added consecutive series of hyperplastic polyps, classical adenomas and normal mucosa samples for a total of 200 specimens. With this series, we conducted an inter-observer study, encompassing ten pathologists with gastrointestinal pathology experience from five European countries, in three rounds in which all cases were microscopically evaluated. An assessment of single morphological criteria was included, and these were correlated with clinical parameters and the mutation status of KRAS, BRAF and PIK3CA and the methylation status of MLH1. Gender, age and localisation were significantly associated with certain types of lesions. Kappa statistics revealed moderate to good inter-observer agreement for polyp classification (kappa = 0.56 to 0.63), but for single criteria, this varied considerably (kappa = 0.06 to 0.82). BRAF mutations were frequently found in hyperplastic polyps (86 %, 62/72) and sessile serrated adenomas (80 %, 41/51). KRAS mutations occurred more frequently in traditional serrated adenomas (78 %, 7/9) and less so in classical adenomas (20 %, 10/51). Single morphological criteria for sessile serrated adenomas showed significant correlation with BRAF mutation (all p

Contains fulltext : 137748pub.pdf (publisher's version ) (Closed access), Criteria for the diagnosis of serrated colorectal lesions (hyperplastic polyp, sessile serrated adenoma without or with dysplasia-which we called mixed polyp-and traditional serrated adenoma) for which consensus has been reached should be validated for applicability in daily practice in terms of inter-observer reproducibility and their association with clinical features and (epi)genetic events. A study set was created from a consecutive series of colorectal polyps (n = 1,926) by selecting all sessile serrated adenomas, traditional serrated adenomas and mixed polyps. We added consecutive series of hyperplastic polyps, classical adenomas and normal mucosa samples for a total of 200 specimens. With this series, we conducted an inter-observer study, encompassing ten pathologists with gastrointestinal pathology experience from five European countries, in three rounds in which all cases were microscopically evaluated. An assessment of single morphological criteria was included, and these were correlated with clinical parameters and the mutation status of KRAS, BRAF and PIK3CA and the methylation status of MLH1. Gender, age and localisation were significantly associated with certain types of lesions. Kappa statistics revealed moderate to good inter-observer agreement for polyp classification (kappa = 0.56 to 0.63), but for single criteria, this varied considerably (kappa = 0.06 to 0.82). BRAF mutations were frequently found in hyperplastic polyps (86 %, 62/72) and sessile serrated adenomas (80 %, 41/51). KRAS mutations occurred more frequently in traditional serrated adenomas (78 %, 7/9) and less so in classical adenomas (20 %, 10/51). Single morphological criteria for sessile serrated adenomas showed significant correlation with BRAF mutation (all p

Cheerleading is associated with substantial morbidity. As such, cheerleading fall-related injuries may cause serious to fatal outcomes especially falls from attempted pyramids. We report on a female adolescent cheerleader age 14 suffering a supracondylar humerus fracture related to a fall from a pyramid. Unfortunately, lateral pinning led to complete iatrogenic radial nerve palsy. However, given an intriguing compensatory athletic function of the wrist she was able to perform cheerleading artistic figures such as flic-flac within four months after the injury with a radial nerve palsy, which is highlighted in an attached video. 18 months after the radial palsy she was admitted to our hospital and underwent neuroma resection of the initially transsected radial nerve at the elbow and sural nerve grafting for radial nerve palsy., Cheerleading kann zu verschiedensten Unfällen führen. Insbesondere bei dem Versuch Pyramiden zu bilden sind bereits Todesfälle aufgetreten. Wir berichten von einer 14-jährigen Cheerleaderin welche bei dem Versuch eine Pyramide zu bilden stürzte und sich eine suprakondyläre Humerusfraktur zuzog. Bei der osteosynthetischen Versorgung kam es leider zu einer kompletten Durchtrennung des N. radialis. Dennoch konnte sie bei der gegebenen erstaunlichen Kompensation ihrer Handgelenksgeweglichkeit weiterhin schwierige Cheerleading Übungen wie Flick-Flack durchführen, was im beigefügten Video verdeutlicht wird. 18 Monate nach Eintreten der Radialisparese wurde sie in unserer Klinik vorstellig und es wurde nach einer Neuromresektion eine Suralis Interposition zur Nervenrekonstruktion durchgeführt.