bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis, design and implementation of a DC/DC boost resonant‐inductor converter with sliding‐mode control
Authors: Momeneh Arash , Castilla Miguel , Moradi Ghahderijani Mohammad , Miret Jaume , Garcia de Vicuña Luis
Published: October 2017

This study presents the analysis, design, and implementation of a DC/DC boost resonant‐inductor converter with the stable operation when using a sliding‐mode control. In addition, the control scheme provides zero‐current switching, fast transient response, and soft converter start‐up. Thus, the resonant‐inductor converter with the proposed control improves notably the performance of the conventional boost converter. The design of the control scheme is facilitated using an averaged large‐signal model of the resonant converter. A laboratory prototype is built and tested to validate the expected features of the resonant converter. Selected experimental results are reported and discussed showing an excellent agreement with the results of the theoretical analysis.
A revised estimate of the distance to the clouds in the Chamaeleon complex using the Tycho–Gaia Astrometric Solution
Authors: Voirin Jordan , Manara Carlo F. , Prusti Timo
Published: October 2017

Context. The determination of the distance to dark star-forming clouds is a key parameter to derive the properties of the cloud itself and of its stellar content. This parameter is still loosely constrained even in nearby star-forming regions.

Aim. We want to determine the distances to the clouds in the Chamaeleon-Musca complex and explore the connection between these clouds and the large-scale cloud structures in the Galaxy.

Methods. We used the newly estimated distances obtained from the parallaxes measured by the Gaia satellite and included in the Tycho–Gaia Astrometric Solution catalog. When known members of a region are included in this catalog we used their distances to infer the distance to the cloud. Otherwise, we analyzed the dependence of the color excess on the distance of the stars and looked for a turn-on of this excess, which is a proxy of the position of the front-edge of the star-forming cloud.

Results. We are able to measure the distance to the three Chamaeleon clouds. The distance to Chamaeleon I is 179-10-10+11+11pc, where the quoted uncertainties are statistical and systematic uncertainties, respectively, ~20 pc further away than previously assumed. The Chamaeleon II cloud is located at the distance of 181-5-10+6+11pc, which agrees with previous estimates. We are able to measure for the first time a distance to the Chamaeleon III cloud of 199-7-11+8+12pc. Finally, the distance of the Musca cloud is smaller than 603603-70-92+91+133 pc. These estimates do not allow us to distinguish between the possibility that the Chamaeleon clouds are part of a sheet of clouds parallel to the Galactic plane, or perpendicular to it.

Conclusions. We measured a larger distance to the Chamaeleon I cloud than assumed in the past, confirmed the distance to the Chamaeleon II region, and measured for the first time the distance to the Chamaleon III cloud. These values are consistent with the scenario in which the three clouds are part of a single large-scale structure. Gaia Data Release 2 will allow us to put more stringent constraints on the distances to these clouds by giving us access to parallax measurements for a larger number of members of these regions.
One Team–Patient, Family, and Health Care Providers: An Interprofessional Education Activity Providing Collaborative and Palliative Care
Authors: Melvin Christina , Lemieux Nancy , Melekis Kelly , Velleman Shelley , Favro Mary , Prelock Patricia
Published: October 2017

The article explains an approach to building interprofessional education (IPE) and interprofessional practice opportunities as well as content in palliative/hospice care within undergraduate and graduate curricula for six health disciplines, including speech-language pathology. Graduate students from nursing, medicine, communication sciences, and disorders, physical therapy, social work and nutrition, as well as undergraduate nursing students participated in one of four IPE training sessions using six videotaped simulation scenes portraying the progression of amyotrophic lateral sclerosis. Learning objectives included (1) engaging in effective interprofessional communication and teamwork, (2) discussing therapeutic patient/family communication, (3) employing supportive holistic care with patients and families at end of life, and (4) relating the patient's physiological assessment findings to the dying process. Students discussed the role of the interprofessional team in end-of-life care and were coached on ways to apply interprofessional communication, a key interprofessional education competency, using patient- and family-centered care principles. Results revealed strong positive agreement among the disciplines regarding the value of the learning opportunities provided during this IPE simulation activity.
Laparoscopic Treatment of Hydrocele of the Canal of Nuck in Pediatric Patients
Authors: Lee Sung
Published: October 2017

Introduction Hydrocele of the canal of Nuck (HCN) causes an inguinal swelling in pediatric females similar to that observed in case of inguinal hernia. HCN should be considered in the differential diagnosis of hernia in such children. Although laparoscopic operations have been reported in several cases for the treatment of HCN in adults, they have not been reported for the treatment in pediatrics. This study aimed to evaluate the outcomes of laparoscopic intracorporeal hydrocelectomy with high ligation as a treatment for HCN in pediatrics.

Materials and Methods I retrospectively reviewed the charts of 26 pediatric females aged ≤10 years who underwent laparoscopic hydrocelectomy with high ligation at Damsoyu Hospital, Seoul, Republic of Korea from September 2012 to December 2016.

Results The mean age was 3.31 (1–10) years. HCN was on the right in 11 patients and on the left in 15. The presenting symptom in all cases was inguinal swelling. HCN was of the hourglass type inside the inguinal canal in 17 patients and in the abdominal cavity outside the inguinal canal in 9. All patients were treated with laparoscopic hydrocelectomy with high ligation. The mean operating time was 17.8 minute (15–30). The wounds were scarcely visible immediately after surgery. There were no postoperative complications and no recurrences on follow-up.

Conclusion Laparoscopic intracorporeal hydrocelectomy with high ligation is effective for HCN in pediatrics owing to its short operating time, excellent cosmesis, and no recurrence.
Community-Acquired MRSA Pericarditis and Mediastinitis in a Previously Healthy Infant
Authors: Sanchez Joselito , Schneider Amanda , Tretter Justin , Shopsin Bo , Al-Qaqaa Yasir , Khaitan Alka , Chadha Tanya
Published: October 2017

Invasive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections disproportionately affect children, but there are few pediatric reports of pericarditis and mediastinitis caused by CA-MRSA in previously healthy children. Here we report a severe case of CA-MRSA pericarditis with extension to the mediastinum and carotid sheath in a previously healthy 8-month-old infant who was successfully treated with surgical interventions and with a combination of daptomycin and vancomycin. The relatively indolent clinical course in this patient was notable given the significant extent of infection. This case highlights the potential virulence of CA-MRSA in previously healthy children and the importance of early diagnosis, prompt drainage, and appropriate antibiotic coverage.
Cadaveric Testing of a Novel Scapholunate Ligament Reconstruction
Authors: Kang Lana , Dy Christopher , Wei Mike , Hearns Krystle , Carlson Michelle
Published: October 2017

Background Existing scapholunate interosseous ligament (SLIL) reconstruction techniques include fixation spanning the radiocarpal joint, which do not reduce the volar aspect of the scapholunate interval and may limit wrist motion.

Questions/Purpose This study tested the ability of an SLIL reconstruction technique that approximates both the volar and dorsal scapholunate intervals, without spanning the radiocarpal joint, to restore static scapholunate relationships.

Materials and Methods Scapholunate interval, scapholunate angle, and radiolunate angle were measured in nine human cadaveric specimens with the SLIL intact, sectioned, and reconstructed. Fluoroscopic images were obtained in six wrist positions. The reconstruction was performed by passing tendon graft through bone tunnels from the dorsal surface toward the volar corner of the interosseous surface. After reduction of the scapholunate articulation, the graft was tensioned within the lunate bone tunnel, secured with an interference screw in the scaphoid, and sutured to the dorsal SLIL remnant. Differences among testing states were evaluated using repeated measures ANOVA.

Results There was a significant increase in the scapholunate interval in all wrist positions after complete SLIL disruption. Compared with the disrupted state, there was a significant decrease in scapholunate interval in all wrist positions after reconstruction using a tendon graft and interference screw.

Conclusion Our SLIL reconstruction technique reconstructs the volar and dorsal ligaments of the scapholunate joint and adequately restores static measures of scapholunate stability. This technique does not tether the radiocarpal joint and aims to optimize volar reduction.

Clinical Relevance Our technique offers an alternative option for SLIL reconstruction that successfully restores static scapholunate relationships.
Preparing Future Health Professionals for Interprofessional Collaborative Practice Part 1: The Context for Learning
Authors: Johnson Alex , Knab Mary , Portney Leslie
Published: October 2017

The importance of interprofessional education and practice has been well documented for all health care disciplines. Our health care delivery system is challenged by the need to prepare health professions graduates with skills that get them ready to function as collaborative members of the health care team. Educators have long struggled to create interprofessional learning environments that would inculcate the needed values and competencies. The purpose of this article is to share one institution's path in developing an integrated context for learning across several disciplines to assure that graduates can fulfill their full professional roles in clinical care, education, advocacy, leadership, and quality improvement. Through a program called IMPACT Practice, the MGH Institute of Health Professions has developed an array of opportunities for students from different programs to interact with each other, emphasizing the collaborative skills that will benefit patients and clients as well as contribute to positive change within the health care system. These opportunities are based on core competencies developed by the Interprofessional Education Collaborative (IPEC) as well as institutional core competencies that go beyond IPEC to address the full professional role. In the second part of this article, the IMPACT experience will be described through the journey of one student in the Communication Sciences and Disorders program.
The Interprofessional Education Environment: Places and Pedagogies
Authors: DiGiovanni Jeffrey , McCarthy John
Published: October 2017

Interprofessional education (IPE) can occur in many places and in many ways. In this article, we focus on the inclusion of standards from the Interprofessional Education Collaborative in several different environments. We consider traditional classrooms and classrooms that integrate clinical placements for varying amounts of instructional time. We also consider a various types of simulations, including virtual and augmented reality, and their potential for advancement of IPE.
An Unusual Complication of Congenital Diaphragmatic Hernia
Authors: Tan E Tian , Sloan Keren , Lakhoo Kokila
Published: October 2017

A term newborn was referred to our unit with a postnatal diagnosis of a right-sided congenital diaphragmatic hernia (CDH). She was managed with high-frequency oscillatory ventilation, inotropic support, and nitric oxide, with planned surgical repair when she was medically optimized. On day 6 of life, there was an acute deterioration causing difficulty maintaining adequate ventilation and the infant requiring increasing analgesia and paralysis, especially during abdominal examination. A repeat X-ray showed distended bowel loops in the right hemithorax when compared with previous films raising suspicion of bowel obstruction. The infant proceeded to emergency laparotomy in the neonatal intensive care unit. She was found to have a right-sided Bochdalek (posterolateral) defect. The entire small bowel was within the thoracic cavity and appeared dusky secondary to obstruction caused by compression of a herniated right liver lobe against the hernia defect. Bowel perfusion improved after reduction and a BioDesign patch was used to repair the defect. The infant went on to have a straightforward recovery and was transferred to her local hospital for ongoing care on day 17. Bowel obstruction is an uncommon complication in the perinatal period in infants with CDH. A high index of suspicion for bowel compromise is needed in neonates who deteriorate acutely after a period of stabilization. Imaging should be obtained as soon as possible and early surgical intervention may be life-saving.
Interview Scores Correlate with Fellow Microsurgical Skill and Performance
Authors: Butler Charles , Suami Hiroo , Garvey Patrick , Liu Jun , Selber Jesse , Schaverien Mark
Published: October 2017

Background The interview process for surgical trainees aims to select those individuals who will perform best during training and have the greatest potential as future surgeons. The objective of this study was to evaluate the relationship between criteria assessed at interview, technical skills, and performance, for the first time, to optimize the selection process for a Microsurgery fellowship.

Methods Twenty microsurgery fellows in three consecutive annual cohorts at a single academic center were prospectively evaluated. At interview, subjects were scored for multiple standardized domains. At the start and at end of the fellowship, microsurgical technical skill was assessed both in the laboratory and operating room (OR) using a validated assessment tool. At the end of the fellowship, there was a final evaluation of performance.

Results At the start, microsurgical skill significantly correlated with almost all domains evaluated at interview, most closely with prior plastic surgery training experience. At the end of the fellowship, skill level improved in all trainees, with the greatest improvement made by the lowest ranked and skilled trainees. The highest ranked trainees, however, made the greatest improvement in speed.

Conclusions The results of this study, for the first time, validate the current interview process to correctly select the highest performing and most skilled candidates and support the effectiveness of a 1-year microsurgical fellowship in improving microsurgical skill in all trainees, irrespective of their initial ability. The importance of valuing the relative quality of prior training and experience at selection is also highlighted.
Digital Devices Improve Chest Tube Management: Results from a Prospective Randomized Trial
Authors: Lococo Filippo , Nachira Dania , Ciavarella Leonardo , Congedo Maria , Porziella Venanzio , Meacci Elisa , Margaritora Stefano , Chiappetta Marco
Published: October 2017

Background Digital devices could help clinical practice measuring the air leak, but their role is still debated. Aim of this study is to test advantages using these devices.

Methods From June 2012 to May 2015, we enrolled 95 patients undergoing lobectomy or wedge resection in a prospective randomized trial. Patients were divided into two groups: group D (digital, 50 patients) evaluated with digital device and group E (empirical, 45 patients) evaluated with water seal. Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were used to select and assess predictors of persistent air leak. In group D, chest drain was removed if the air leak was absent or < 0.5 L/h for 12 consecutive hours and in group E if clinical signs of air leak were absent.

Results Mean hospitalization and mean chest tube stay was 6.0 ± 3.3 and 4.4 ± 3.2 days, respectively, prolonged air leak occurred in nine (8%). Hospitalization was 5.8 ± 2.5 versus 6.2 ± 4.2 days (p = 0.5), while mean chest tube stay was 4.1 ± 2.0 versus 4.6 ± 3.5 days (p = 0.4) in group D and group E, respectively. Clamping test was needed in one patient in group D and in seven in group E (p = 0.019). At multivariate analysis, heart disease (p < 0.0001), lobectomy (p < 0.0001), fused fissure (p < 0.0001), and air leakage in first postoperative (p.o.) day were predictors of persistent air leak (AUC on the ROC curve of 69.7%, sensibility: 77.8%). In group D, an air leak value > 0.2 L/h with spikes over 0.5 L/h in third p.o. was predictive of persistent air leak, with chest tube duration of 7.73 ± 5.20 versus 4.32 ± 1.33 days (AUC: 83%, sensitivity: 80%, p < 0.0001).

Conclusion In our experience, digital devices reduced observer variability and mistakes in chest tube management, thus identifying patients at risk for prolonged air leak.
Präzisionsonkologie und molekulare Tumorboards – Konzepte, Chancen und Herausforderungen
Authors: Holch Julian , Westphalen Christoph , Hiddemann Wolfgang , Heinemann Volker , Jung Andreas , Metzeler Klaus
Published: October 2017

Recent developments in genomics allow a more and more comprehensive genetic analysis of human malignancies, and have sparked hopes that this will contribute to the development of novel targeted, effective and well-tolerated therapies.

While targeted therapies have improved the prognosis of many cancer patients with certain tumor types, “precision oncology” also brings along new challenges. Highly personalized treatment strategies require new strategies for clinical trials and translation into routine clinical practice. We review the current technical approaches for “universal genetic testing” in cancer, and potential pitfalls in the interpretation of such data. We then provide an overview of the available evidence supporting treatment strategies based on extended genetic analysis. Based on the available data, we conclude that “precision oncology” approaches that go beyond the current standard of care should be pursued within the framework of an interdisciplinary “molecular tumor board”, and preferably within clinical trials.
Akuter Vorderwandinfarkt durch Koronarthrombus aufgrund eines spontanen Intimaeinrisses
Authors: Kahles Florian , Schuh Alexander , Lehrke Michael , Burgmaier Mathias , Marx Nikolaus , Reith Sebastian
Published: October 2017

Anamnese Wir berichten über einen adipösen 51-jährigen Patienten, der über plötzlich eintretende thorakale Schmerzen mit Ausstrahlung in den linken Arm klagt. Als kardiovaskuläre Risikofaktoren werden arterielle Hypertonie und Nikotinabusus angegeben.

Untersuchungen Bei unauffälligem EKG-Befund, jedoch steigenden Troponinwerten (37 pg/ml; Norm < 14 pg/ml) wird eine Herzkatheteruntersuchung durchgeführt. Hierbei wird bei ansonsten glatten Koronargefäßen eine Kontrastmittelaussparung (a.e. einem Thrombus entsprechend) des RIVA gesehen. Mit Hilfe von OCT kann ein Intimaeinriss mit assoziiertem Thrombusmaterial nachgewiesen werden.

Therapie Es erfolgt eine Implantation eines beschichteten Stents im Bereich des medialen RIVA sowie ein Loading mit Acetylsalicylsäure/Ticagrelor und eine Eptifibatid-Bolusgabe.

Verlauf Nach Koronarintervention ist der Patient beschwerdefrei. Eine medikamentöse Therapie mittels ASS, Ticagrelor, Metoprolol und Simvastatin wird initiiert.

Folgerung Dem Koronarthrombus des Patienten liegt eine spontane Koronardissektion (SCAD) im Bereich des medialen RIVA zugrunde. SCAD stellt eine wichtige Differenzialdiagnose des ACS dar, welche nach Möglichkeit mittels erweiterter bildgebender Diagnostik gesichert werden sollte. Leitlinienempfehlungen stehen aktuell noch aus.
Endoscopic full-thickness resection for T1 early rectal cancer: a case series and video report
Authors: Soriani Paola , Tontini Gian , Neumann Helmut , de Nucci Germana , De Toma Domenico , Bruni Barbara , Vavassori Sara , Pastorelli Luca , Vecchi Maurizio , Lagoussis Pavlos
Published: October 2017

Background and study aims Endoscopic treatment of malignant colorectal polyps is often challenging, especially for early rectal cancer (ERC) localized close to the dentate line. Conversely, the surgical approach may result in temporary or definitive stoma and in frequent post-surgical complications. The Full-Thickness Resection Device (FTRD®) System (Ovesco Endoscopy, Tübingen, Germany) is a novel system that, besides having other indications, appears to be promising for wall-thickness excision of intestinal T1 carcinoma following incomplete endoscopic resection. However, follow-up data on patients treated with this device are scarce, particularly for ERC.

Patients and methods Six consecutive patients with incomplete endoscopic resection of T1-ERC were treated with the FTRD and their long-term outcomes were evaluated based on a detailed clinical and instrumental assessment.

Results The endoscopic en bloc full-thickness resection was technically feasible in all patients. The histopathologic analysis showed a complete endoscopic resection in all cases, and a full-thickness excision in four. Neither complications, nor disease recurrence were observed during the 1-year follow-up period.

Conclusions The FTRD System is a promising tool for treating ERC featuring a residual risk of disease recurrence after incomplete endoscopic mucosal resection in patients unfit for surgery or refusing a surgical approach.
Patientenpräferenzen bei der Auswahl von Antirheumatika: Eine wahlbasierte Conjoint-Analyse bei Patienten mit
rheumatoider Arthritis
Authors: Kessler Verena , Schirmer Norbert , Holzkämper Thorsten , Knürr Hanna , Barth Simon , Sailer Florian
Published: October 2017

Zielsetzung Diese Studie untersuchte , welche Eigenschaften medikamentöser Therapieoptionen für Patienten mit rheumatoider Arthritis
(RA) in Deutschland am wichtigsten sind, und ob sich die Präferenzen unterscheiden, wenn die Patienten konventionelle Antirheumatika oder
Biologika erhalten.

Methodik Über Rheumatologen wurden deutschlandweit Erwachsene mit mittelschwerer und schwerer RA rekrutiert, 50 % nur mit
konventionellen krankheitsmodifizierenden Antirheumatika (Biologika-naiv), 50 % mit Biologika behandelt. Die finale Befragung erfolgte mit
einer wahlbasierten Conjoint-Analyse (CBCA). Die verwendeten 6 Attribute mit je 4 Ausprägungen wurden basierend auf qualitativen Interviews
(21 Patienten) und einer quantitativen Vorstudie (62 Patienten) entwickelt.

Ergebnisse An der Hauptstudie nahmen 180 Patienten teil (113 mit mittelschwerer, 67 mit schwerer RA; 90 Biologika naiv, 90 Biologika
behandelt). Unabhängig ob Biologika-behandelt oder naiv, war den Patienten bei der RA-Therapie die Vermeidung langfristiger negativer
gesundheitlicher Auswirkungen (durch Krankheitsfortschritt oder Therapie) wichtiger als möglichst geringe Einschränkungen durch
Nebenwirkungen (rel. Wichtigkeit 32,8 % bzw. 19,3 %). Es folgten verzögerter Krankheitsfortschritt (13,9 %), Schmerzlinderung (13,5 %), Art
und Häufigkeit der Verabreichung (13,3 %), erleichterte Bewältigung von Alltagsaufgaben (7,2 %). Biologika-naive Patienten bevorzugten die
Tabletteneinnahme 1x täglich gegenüber allen anderen Darreichungsformen, Biologika-erfahrene Patienten bevorzugten eine Injektion s. c. alle
2 Wochen.

Schlussfolgerung Die CBCA liefert valide Daten, welche Eigenschaften der medikamentösen RA-Therapie für Patienten in Deutschland
wichtig sind. Werden Patientenpräferenzen mitberücksichtigt, sind positive Effekte auf Therapietreue und subjektives Wohlbefinden möglich
sowie Effekte auf den Gesamterfolg der RA-Therapie denkbar.
Intradialytische Ernährung – Oral? Enteral? Parenteral?
Authors: Brodmann Doreen
Published: October 2017

Hintergrund Mangelernährung ist sowohl in der Normalbevölkerung als auch bei Dialysepatienten häufig. Je nach untersuchtem Parameter sind ca. 20 – 60 % der Dialysepatienten von dieser – bei dieser Patientengruppe Protein-Energy-Wasting (PEW) genannten – Erkrankung betroffen.

Methoden Literaturreview der aktuellen Leitlinien, Studien und Metaanalysen.

Ergebnisse Nach Diagnosestellung stellt neben der Minimierung Mangelernährung begünstigender Faktoren wie z. B. chronischer Infekte, Schluckstörungen, sozialer Ursachen und viele mehr die Steigerung und Sicherstellung der Kalorien- und Eiweißzufuhr eine große Herausforderung bei diesen meist schwachen und appetitlosen Patienten dar. Die Möglichkeiten zur Optimierung der Ernährung während der Hämodialyse (intradialytische Ernährung) umfassen neben der Bereitstellung einer hochwertigen und möglichst eiweißreichen Mahlzeit zur Minimierung der Katabolie die Anreicherung der Nahrung mit Maltodextrin oder Eiweißkonzentraten, die IDEE (intradialytische enterale Ernährung) und die IDPE (intradialytische parenterale Ernährung). Jedoch stellt die Hämodialyse mit 3-mal pro Woche jeweils 4 Stunden nur einen geringen Zeitanteil am Leben des Patienten dar. Ernährungsmaßnahmen allein während der Dialyse sind deshalb nicht ausreichend und müssen um Maßnahmen für die Zeit außerhalb der Dialysen ergänzt werden.
Medizinische Thromboseprophylaxestrümpfe – große Wirkung in Zulassungsstudien von Edoxaban
Authors: Kroeger Knut , Kujath Peter
Published: October 2017

Der Nutzen von medizinischen Thromboseprophylaxestrümpfen (AES) als physikalisches Mittel zur Prävention von venösen Thrombosen der unteren Extremität wird im Zeitalter der evidenzbasierten Medizin infrage gestellt. Die aktuellen S3-Leitlinien schreiben sogar, dass ihre Nichtanwendung in den allermeisten Fällen explizit im Empfehlungskorridor dieser Leitlinie liegt. Die niedermolekularen Heparine (NMH) und die direkten oralen Antikoagulanzien (DOAK) haben über Studien zur Thromboseprophylaxe bei elektivem Knie- und Hüftgelenkersatz ihre Zulassung erhalten, allerdings ist zur Anwendung von AES in diesen Zulassungsstudien nichts bekannt. Nun wurden erstmals die Ergebnisse der zusätzlichen Wirkung der AES in den Zulassungsstudien von Edoxaban publiziert. Danach betrug die Inzidenz von venösen Thromboembolien 6,0%, wenn AES getragen wurden, und 13,0%, wenn keine AES getragen wurden. Da in den Zulassungsstudien von NMH und den DOAKs nicht die Anwendung von AES kontrolliert wurde, kann nicht gesagt werden, wie groß der Effekt der AES auf das Gesamtergebnis ist, und die Studienergebnisse gelten nur vor dem Hintergrund der allgemeinen Anwendung von AES.
Tiefes Venensystem: Hybridverfahren zur Therapie der iliofemoralen chronischen venösen Obstruktionen
Authors: Grommes Jochen , Gombert Alexander , Barbati Mohammed , von Trotha Klaus , Schleimer Karina , Jalaie Houman
Published: October 2017

Hintergrund Die endovaskuläre Rekanalisation chronischer Verschlüsse der iliofemoralen oder kavalen Venen zeigt vielversprechende Offenheitsraten. Allerdings reduziert sich die Offenheit deutlich, wenn der Verschluss auch die V. femoralis und deren Zuflüsse betrifft. Die Endophlebektomie ermöglicht im Rahmen eines Hybridverfahrens durch Herstellung des Einstroms das Outcome zu verbessern und Frühverschlüsse zu vermeiden. Ziel der Arbeit ist es, die Technik und die bisher veröffentlichten Ergebnisse vorzustellen.

Ergebnisse In dem Hybridverfahren erfolgt die venöse Rekanalisation und eine Endophlebektomie als Kombinationseingriff. Bisher liegen nur 4 Publikation mit mehr als 10 Patienten vor mit einem Follow-up zwischen 6 und 24 Monaten. Die primäre bzw. sekundäre Offenheit variiert zwischen 0 und 77% bzw. 30 und 93%. Allerdings wurde bei der überwiegenden Zahl der Patienten eine Verbesserung der klinischen Symptomatik beschrieben.

Schlussfolgerung Obwohl nur wenige Daten zum Hybridverfahren und zur Endophlebektomie vorliegen, scheint es diese Technik zu ermöglichen, auch venöse Verschlussprozesse, die bis in den femoralen venösen Zufluss reichen, zu behandeln.
Management von Stentprotheseninfektionen nach EVAR und TEVAR – Fallserie und Literaturübersicht
Authors: Betz Thomas , Töpel Ingolf , Steinbauer Markus , Uhl Christian
Published: October 2017

Einleitung Eine Stentprotheseninfektion nach endovaskulärer Versorgung ist eine seltene, jedoch schwere Komplikation mit hoher Mortalität. Aufgrund der steigenden Anzahl von endovaskulären Eingriffen ist mit einer Zunahme von Stentprotheseninfektionen zu rechnen. Eine einheitliche Leitlinie zu Diagnostik und Therapie dieses Krankheitsbilds existiert nicht. Die Datenlage beruht auf Fallberichten, retrospektiven Untersuchungen und Metaanalysen, oft aus der offenen Aortenchirurgie. Die Diagnosestellung kann mitunter schwierig sein. Die Klinik des Patienten, die Bildgebung und der kulturelle Erregernachweis sind entscheidend. Wenn möglich sollte eine Sanierung des Infektfokus mit Ausbau der infizierten Prothese erfolgen. Verschiedene Verfahren und Materialien kommen hierbei zum Einsatz. Zusätzlich sollte eine Langzeitantibiose unter engmaschiger Kontrolle der Entzündungsparameter gegeben werden.

Methodik Es wurde eine retrospektive Analyse aller Patienten, die zwischen Januar 2008 und Mai 2017 an unserer Klinik aufgrund einer Stentprotheseninfektion behandelt wurden, durchgeführt. Die Studienendpunkte waren Infektfreiheit, Überleben und primäre Offenheit der Rekonstruktion. Zusätzlich wurde elektronisch nach gefäßchirurgischer Literatur gesucht, die sich mit der Therapie von Stentprotheseninfektionen nach EVAR (Endovascular aortic repair) und TEVAR (Thoracic endovascular aortic repair) befasst.

Ergebnisse Insgesamt wurde bei 3 Patienten (100% Männer, Durchschnittsalter 77 Jahre) eine Stentprotheseninfektion diagnostiziert. In allen Fällen handelte es sich um eine Stentinfektion nach EVAR. Bei allen Patienten wurde der Stent-Graft entfernt und eine anatomische Rekonstruktion mit Homograft oder xenogenem Material durchgeführt. Ein Erregernachweis gelang in 2 von 3 Fällen. Alle Patienten erhielten eine Langzeitantibiose über 12 Wochen. Die 30-Tages-Mortalität lag bei 0%, im Nachbeobachtungszeitraum kam es zu keinem Re-Infekt. Ein Patient verstarb 2 Monate postoperativ an einer Darmperforation mit Peritonitis, ein weiterer Patient 92 Monate postoperativ an einem kleinzelligen Bronchialkarzinom. Die primäre Offenheit der Rekonstruktionen lag bei 100%. In der Literatur weist die konservative Therapie einer Stentprotheseninfektion eine sehr hohe Mortalität auf, wobei sie bei Patienten mit aortoenteraler oder aortobronchialer Fistel und konservativer Therapie am höchsten ist. Bei operativer Therapie der Stentprotheseninfektion ist diese deutlich niedriger.

Zusammenfassung Die chirurgische Herdsanierung, der Prothesenersatz und die begleitende antibiotische Therapie sind entscheidend für das Langzeitergebnis nach Endostentinfektion. Eine konservative Therapie sollte nur bei chirurgisch nicht sanierbarem Fokus oder inoperablen Patienten durchgeführt werden.
PET-CT bei vaskulärem Graft-Infekt
Authors: Husmann Lars , Hasse Barbara
Published: October 2017

Die 18F-Fluordesoxyglukose-Positronenemissionstomografie-Computertomografie (FDG-PET-CT) hat eine hohe diagnostische Genauigkeit bei vaskulären Graft-Infekten. Auch bei Therapieverlaufskontrollen von Graft-Infekten scheint der Einsatz der FDG-PET-CT sinnvoll, da ein signifikanter Einfluss auf das Patientenmanagement gezeigt werden konnte; ergänzende Daten größerer Studien sind aktuell jedoch noch ausstehend.
Endovaskuläre Rekanalisation chronischer Beckenvenenverschlüsse
Authors: Lichtenberg Michael , Jalaie Houman
Published: October 2017

Die endovaskuläre Therapie von iliofemoralen Thrombosen wird in aktuellen nationalen und internationalen Leitlinien bei jungen Patienten zur Vermeidung eines postthrombotischen Syndroms als Therapieoption empfohlen. Hierzu stehen die endovaskuläre lokale Lysetherapie sowie pharmakomechanische oder rein mechanisch durchgeführte Techniken zur Verfügung. Die endovaskuläre Therapie von chronischen V.-cava-inferior- und Beckenvenenverschlüssen mit venösen Stents stellt eine effektive Therapie bei Patienten dar, die unter einem postthrombotischen Syndrom leiden. Hybridoperationen mit Anlage einer arteriovenösen Fistel (AV-Fistel) oder einer Endophlebektomie kommen bei einer Beteiligung der V. femoralis communis in Betracht.
Surface acceptor states in MBE-grown CdTe layers
Authors: Wichrowska Karolina , Wosinski Tadeusz , Tkaczyk Zbigniew , Kolkovsky Valery , Karczewski Grzegorz
Published: October 2017

A deep-level hole trap associated with surface defect states has been revealed with deep-level transient spectroscopy investigations of metal-semiconductor junctions fabricated on nitrogen doped p-type CdTe layers grown by the molecular-beam epitaxy technique. The trap displayed the hole-emission activation energy of 0.33 eV and the logarithmic capture kinetics indicating its relation to extended defect states at the metal-semiconductor interface. Strong electric-field-induced enhancement of the thermal emission rate of holes from the trap has been attributed to the phonon-assisted tunneling effect from defect states involving very large lattice relaxation around the defect and metastability of its occupied state. Passivation with ammonium sulfide of the CdTe surface, prior to metallization, results in a significant decrease in the trap density. It also results in a distinct reduction in the width of the surface-acceptor-state-induced hysteresis loops in the capacitance vs. voltage characteristics of the metal-semiconductor junctions.
Constrained projective quantum states for the degenerate Plebański gravity
Authors: Okołów Andrzej
Published: October 2017

So far, projective quantum states have been constructed for a number of field theories including loop quantum gravity. However, these states are kinematic in the sense that their construction does not take into account the dynamics of the theories. In particular, the construction neglects constraints on phase spaces. Here we present projective quantum states which satisfy a constraint—the states are built for a “toy-theory” called degenerate Plebański gravity.
Antisymmetric vortex interactions in the wake behind a step cylinder
Authors: Tian Cai , Jiang Fengjian , Pettersen Bjørnar , Andersson Helge I.
Published: October 2017

Flow around a step cylinder at the Reynolds number 150 was simulated by directly solving the full Navier-Stokes equations. The configuration was adopted from the work of Morton and Yarusevych [“Vortex shedding in the wake of a step cylinder,” Phys. Fluids 22, 083602 (2010)], in which the wake dynamics were systematically described. A more detailed investigation of the vortex dislocation process has now been performed. Two kinds of new loop vortex structures were identified. Additionally, antisymmetric vortex interactions in two adjacent vortex dislocation processes were observed and explained. The results in this letter serve as a supplement for a more thorough understanding of the vortex dynamics in the step cylinder wake.
Statistical uncertainty in the dark-field and transmission signal of grating interferometry
Authors: Harti R. P. , Strobl M. , Morgano M. , Valsecchi J. , Grünzweig C.
Published: October 2017

We present a framework to estimate the fundamental statistical uncertainty of grating interferometer experiments based on a Monte-Carlo method. Using the framework, we are able to determine the uncertainty of individual measurements as well as suggesting experimental protocols that minimise the statistical uncertainty for given overall exposure times. The method presented here is valid for both X-rays and neutrons and can be generalised for any modulation measurement.
On the propagation of particulate gravity currents in circular and semi-circular channels partially filled with homogeneous or stratified ambient fluid
Authors: Zemach T. , Chiapponi L. , Petrolo D. , Ungarish M. , Longo S. , Di Federico V.
Published: October 2017

We present a combined theoretical-experimental investigation of particle-driven gravity currents advancing in circular cross section channels in the high-Reynolds number Boussinesq regime; the ambient fluid is either homogeneous or linearly stratified. The predictions of the theoretical model are compared with experiments performed in lock–release configuration; experiments were performed with conditions of both full-depth and partial-depth locks. Two different particles were used for the turbidity current, and the full range 0≤S≤1 of the stratification parameter was explored (S = 0 corresponds to the homogeneous case and S = 1 when the density of the ambient fluid and of the current are equal at the bottom). In addition, a few saline gravity currents were tested for comparison. The results show good agreement for the full-depth configuration, with the initial depth of the current in the lock being equal to the depth of the ambient fluid. The agreement is less good for the partial-depth cases and is improved by the introduction of a simple adjustment coefficient for the Froude number at the front of the current and accounting for dissipation. The general parameter dependencies and behaviour of the current, although influenced by many factors (e.g., mixing and internal waves), are well predicted by the relatively simple model.
Tetragonal (K, Na)NbO3 based lead-free single crystal: Growth, full tensor properties, and their orientation dependence
Authors: Zheng Limei , Wang Junjun , Liu Xuedong , Yang Liya , Lu Xiaoyan , Li Yanran , Huo Da , Lü Weiming , Yang Bin , Cao Wenwu
Published: October 2017

A Li and Ta modified (K, Na)NbO3 lead-free single crystal with a large size (13 × 10 × 20 mm3) has been grown by using the top-seeded solution growth method. The large size allows us to carry out an extensive study on this tetragonal crystal. We have measured a complete set of elastic, dielectric, and piezoelectric constants for the [001]C poled crystal with the single domain state. The crystal exhibits high shear piezoelectricity with d15 = 518 pC/N and k15 = 0.733, showing excellent potential in shear electro-sonic energy transformation devices. It is found that the high shear piezoelectricity originates from the vicinity of orthorhombic-tetragonal phase transition, which favors polarization rotation greatly. The orientation dependence of longitudinal dielectric, piezoelectric, and elastic constants and electromechanical coupling factor in the 3-dimentional space were calculated based on the single domain dataset. We believe that this work is of great importance for both fundamental studies and device designs for lead-free materials.
The study of an extended hierarchy equation of motion in the spin-boson model: The cutoff function of the sub-Ohmic spectral density
Authors: Duan Chenru , Wang Qianlong , Tang Zhoufei , Wu Jianlan
Published: October 2017

Following a recently proposed decomposition technique [C. R. Duan et al., Phys. Rev. B 95, 214308 (2017)], we inspect the zero-temperature spin-boson model for five different cutoff functions of the spectral density. With oscillatory and non-oscillatory exponentially decaying functions to decompose the bath correlation function, the hierarchy equation of motion is reliably extended to each spectral density under our investigation. The predicted spin dynamics is gradually converged with the increase of the hierarchic expansion order and the number of decomposing basis functions. Our systematic study of different cutoff functions expands previous results of the delocalized-localized phase transition with the exponential and sudden cutoffs in the spectral density.
Micro-photoluminescence mapping of surface plasmon enhanced light emissions from InGaN/GaN quantum wells
Authors: Tateishi Kazutaka , Wang Pangpang , Ryuzaki Sou , Funato Mitsuru , Kawakami Yoichi , Okamoto Koichi , Tamada Kaoru
Published: October 2017

We conducted photoluminescence (PL) mapping to elucidate the detailed mechanism of PL enhancement based on the energy transfer from excitons to surface plasmon polaritons (SPPs) in silver-coated InGaN quantum wells (QWs). The PL mapping for bare InGaN QWs showed positive or negative correlations between the PL peak intensity and wavelength. These correlations are normally caused by exciton localization and the quantum confined Stark effect, respectively; however, they did not appear in the silver-coated region of the InGaN QWs, and the wavelength distribution shifted into shorter wavelengths due to the SP-induced PL enhancement. These results suggest that the energy transfer from the excitons to the SPPs should be much faster than that in the exciton localization and charge screening processes of the piezoelectric field in QWs.
Study of surface modes on a vibrating electrowetting liquid lens
Authors: Strauch Matthias , Shao Yifeng , Bociort Florian , Urbach H. Paul
Published: October 2017

The increased usage of liquid lenses motivates us to investigate surface waves on the liquid's surface. During fast focal switching, the surface waves decrease the imaging quality. We propose a model that describes the surface modes appearing on a liquid lens and predicts the resonance frequencies. The effects of those surface modes on a laser beam are simulated using Fresnel propagation, and the model is verified experimentally.
The application of large amplitude oscillatory stress in a study of fully formed fibrin clots
Authors: Lamer T. F. , Thomas B. R. , Curtis D. J. , Badiei N. , Williams P. R. , Hawkins K.
Published: October 2017

The suitability of controlled stress large amplitude oscillatory shear (LAOStress) for the characterisation of the nonlinear viscoelastic properties of fully formed fibrin clots is investigated. Capturing the rich nonlinear viscoelastic behaviour of the fibrin network is important for understanding the structural behaviour of clots formed in blood vessels which are exposed to a wide range of shear stresses. We report, for the first time, that artefacts due to ringing exist in both the sample stress and strain waveforms of a LAOStress measurement which will lead to errors in the calculation of nonlinear viscoelastic properties. The process of smoothing the waveforms eliminates these artefacts whilst retaining essential rheological information. Furthermore, we demonstrate the potential of LAOStress for characterising the nonlinear viscoelastic properties of fibrin clots in response to incremental increases of applied stress up to the point of fracture. Alternating LAOStress and small amplitude oscillatory shear measurements provide detailed information of reversible and irreversible structural changes of the fibrin clot as a consequence of elevated levels of stress. We relate these findings to previous studies involving large scale deformations of fibrin clots. The LAOStress technique may provide useful information to help understand why some blood clots formed in vessels are stable (such as in deep vein thrombosis) and others break off (leading to a life threatening pulmonary embolism).
Rogue waves in space dusty plasmas
Authors: Chowdhury N. A. , Mannan A. , Mamun A. A.
Published: October 2017

The modulational instability of dust-acoustic (DA) waves (DAWs) and corresponding DA rogue waves (DARWs) in a realistic space dusty plasma system (containing inertial warm positively and negatively charged dust, isothermal ions, and super-thermal kappa distributed electrons) has been theoretically investigated. The nonlinear Schrödinger equation is derived by using a reductive perturbation method for this investigation. It is observed that the dusty plasma system under consideration supports two branches of modes, namely, fast and slow DA modes, and that both of these two modes can be stable or unstable depending on the sign of ratio of the dispersive and nonlinear coefficients. The numerical analysis has shown that the basic features (viz., stability/instability, growth rate, amplitude, and width of the rogue structures, etc.) of the DAWs associated with the fast DA modes are significantly modified by super-thermal parameter (κ) and other various plasma parameters. The results of our present investigation should be useful for understanding DARWs in space plasma systems, viz., mesosphere and ionosphere.
Off-resonance NOVEL
Authors: Jain Sheetal K. , Mathies Guinevere , Griffin Robert G.
Published: October 2017

Dynamic nuclear polarization (DNP) is theoretically able to enhance the signal in nuclear magnetic resonance (NMR) experiments by a factor γe/γn, where γ’s are the gyromagnetic ratios of an electron and a nuclear spin. However, DNP enhancements currently achieved in high-field, high-resolution biomolecular magic-angle spinning NMR are well below this limit because the continuous-wave DNP mechanisms employed in these experiments scale as ω0−n where n ∼ 1–2. In pulsed DNP methods, such as nuclear orientation via electron spin-locking (NOVEL), the DNP efficiency is independent of the strength of the main magnetic field. Hence, these methods represent a viable alternative approach for enhancing nuclear signals. At 0.35 T, the NOVEL scheme was demonstrated to be efficient in samples doped with stable radicals, generating 1H NMR enhancements of ∼430. However, an impediment in the implementation of NOVEL at high fields is the requirement of sufficient microwave power to fulfill the on-resonance matching condition, ω0I = ω1S, where ω0I and ω1S are the nuclear Larmor and electron Rabi frequencies, respectively. Here, we exploit a generalized matching condition, which states that the effective Rabi frequency, ω1Seff, matches ω0I. By using this generalized off-resonance matching condition, we generate 1H NMR signal enhancement factors of 266 (∼70% of the on-resonance NOVEL enhancement) with ω1S/2π = 5 MHz. We investigate experimentally the conditions for optimal transfer of polarization from electrons to 1H both for the NOVEL mechanism and the solid-effect mechanism and provide a unified theoretical description for these two historically distinct forms of DNP.
Breakdown voltage for surface dielectric barrier discharge ignition in atmospheric air
Authors: Soloviev V. R. , Selivonin I. V. , Moralev I. A.
Published: October 2017

Breakdown voltage for surface dielectric barrier discharge ignition in atmospheric air has been measured for different parameters of the dielectric barrier, exposed electrode mounting, and supply voltage frequency. The analytical model of the discharge onset has been developed. It reveals that the discharge breakdown voltage is proportional to the square root of the dielectric barrier thickness and weakly depends on dielectric relative permittivity. The trajectory of discharge breakdown is managed mainly by gas properties and its density; it does not depend on dielectric barrier parameters and the breakdown voltage value. The analytical solution is in good agreement with the obtained experimental data and indicates the validity of the 2D approach for the breakdown process in the case of discharge between the strip and flat electrodes separated by a dielectric barrier.
Time resolved measurements of hydrogen ion energy distributions in a pulsed 2.45 GHz microwave plasma
Authors: Megía-Macías A. , Cortázar O. D. , Tarvainen O. , Koivisto H.
Published: October 2017

A plasma diagnostic study of the Ion Energy Distribution Functions (IEDFs) of H+, H2+, and H3+ ions in a 2.45 GHz hydrogen plasma reactor called TIPS is presented. The measurements are conducted by using a Plasma Ion Mass Spectrometer with an energy sector and a quadrupole detector from HIDEN Analytical Limited in order to select an ion species and to measure its energy distribution. The reactor is operated in the pulsed mode at 100 Hz with a duty cycle of 10% (1 ms pulse width). The IEDFs of H+, H2+, and H3+ are obtained each 5 μs with 1 μs time resolution throughout the entire pulse. The temporal evolution of the plasma potential and ion temperature of H+ is derived from the data. It is shown that the plasma potential is within the range of 15–20 V, while the ion temperature reaches values of 0.25–1 eV during the pulse and exhibits a fast transient peak when the microwave radiation is switched off. Finally, the ion temperatures are used to predict the transverse thermal emittance of a proton beam extracted from 2.45 GHz microwave discharges.