54 research outputs found
Gate-tuned normal and superconducting transport at the surface of a topological insulator
Three-dimensional topological insulators are characterized by the presence of
a bandgap in their bulk and gapless Dirac fermions at their surfaces. New
physical phenomena originating from the presence of the Dirac fermions are
predicted to occur, and to be experimentally accessible via transport
measurements in suitably designed electronic devices. Here we study transport
through superconducting junctions fabricated on thin Bi2Se3 single crystals,
equipped with a gate electrode. In the presence of perpendicular magnetic field
B, sweeping the gate voltage enables us to observe the filling of the Dirac
fermion Landau levels, whose character evolves continuously from electron- to
hole-like. When B=0, a supercurrent appears, whose magnitude can be gate tuned,
and is minimum at the charge neutrality point determined from the Landau level
filling. Our results demonstrate how gated nano-electronic devices give control
over normal and superconducting transport of Dirac fermions at an individual
surface of a three-dimensional topological insulator.Comment: 28 pages, 5 figure
Transfusion-transmitted infections
Although the risk of transfusion-transmitted infections today is lower than ever, the supply of safe blood products remains subject to contamination with known and yet to be identified human pathogens. Only continuous improvement and implementation of donor selection, sensitive screening tests and effective inactivation procedures can ensure the elimination, or at least reduction, of the risk of acquiring transfusion transmitted infections. In addition, ongoing education and up-to-date information regarding infectious agents that are potentially transmitted via blood components is necessary to promote the reporting of adverse events, an important component of transfusion transmitted disease surveillance. Thus, the collaboration of all parties involved in transfusion medicine, including national haemovigilance systems, is crucial for protecting a secure blood product supply from known and emerging blood-borne pathogens
Safety and immunogenicity of the two-dose heterologous Ad26.ZEBOV and MVA-BN-Filo Ebola vaccine regimen in children in Sierra Leone: a randomised, double-blind, controlled trial
BackgroundâChildren account for a substantial proportion of cases and deaths from Ebola virus disease. We aimed to assess the safety and immunogenicity of a two-dose heterologous vaccine regimen, comprising the adenovirus type 26 vector-based vaccine encoding the Ebola virus glycoprotein (Ad26.ZEBOV) and the modified vaccinia Ankara vectorbased vaccine, encoding glycoproteins from the Ebola virus, Sudan virus, and Marburg virus, and the nucleoprotein from the Tai Forest virus (MVA-BN-Filo), in a paediatric population in Sierra Leone.
MethodsâThis randomised, double-blind, controlled trial was done at three clinics in Kambia district, Sierra Leone. Healthy children and adolescents aged 1â17 years were enrolled in three age cohorts (12â17 years, 4â11 years, and 1â3 years) and randomly assigned (3:1), via computer-generated block randomisation (block size of eight), to receive an intramuscular injection of either Ad26.ZEBOV (5 Ă 1010 viral particles; first dose) followed by MVA-BN-Filo (1 Ă 108 infectious units; second dose) on day 57 (Ebola vaccine group), or a single dose of meningococcal quadrivalent (serogroups A, C, W135, and Y) conjugate vaccine (MenACWY; first dose) followed by placebo (second dose) on day 57 (control group). Study team personnel (except for those with primary responsibility for study vaccine preparation), participants, and their parents or guardians were masked to study vaccine allocation. The primary outcome was safety, measured as the occurrence of solicited local and systemic adverse symptoms during 7 days after each vaccination, unsolicited systemic adverse events during 28 days after each vaccination, abnormal laboratory results during the study period, and serious adverse events or immediate reportable events throughout the study period. The secondary outcome was immunogenicity (humoral immune response), measured as the concentration of Ebola virus glycoprotein-specific binding antibodies at 21 days after the second dose. The primary outcome was assessed in all participants who had received at least one dose of study vaccine and had available reactogenicity data, and immunogenicity was assessed in all participants who had received both vaccinations within the protocol-defined time window, had at least one evaluable post-vaccination sample, and had no major protocol deviations that could have influenced the immune response. This study is registered at ClinicalTrials.gov, NCT02509494.
FindingsâFrom April 4, 2017, to July 5, 2018, 576 eligible children or adolescents (192 in each of the three age cohorts) were enrolled and randomly assigned. The most common solicited local adverse event during the 7 days after the first and second dose was injection-site pain in all age groups, with frequencies ranging from 0% (none of 48) of children aged 1â3 years after placebo injection to 21% (30 of 144) of children aged 4â11 years after Ad26.ZEBOV vaccination. The most frequently observed solicited systemic adverse event during the 7 days was headache in the 12â17 years and 4â11 years age cohorts after the first and second dose, and pyrexia in the 1â3 years age cohort after the first and second dose. The most frequent unsolicited adverse event after the first and second dose vaccinations was malaria in all age cohorts, irrespective of the vaccine types. Following vaccination with MenACWY, severe thrombocytopaenia was observed in one participant aged 3 years. No other clinically significant laboratory abnormalities were observed in other study participants, and no serious adverse events related to the Ebola vaccine regimen were reported. There were no treatment-related deaths. Ebola virus glycoprotein-specific binding antibody responses at 21 days after the second dose of the Ebola virus vaccine regimen were observed in 131 (98%) of 134 children aged 12â17 years (9929 ELISA units [EU]/mL [95% CI 8172â12 064]), in 119 (99%) of 120 aged 4â11 years (10 212 EU/mL [8419â12 388]), and in 118 (98%) of 121 aged 1â3 years (22 568 EU/mL [18 426â27 642]).
InterpretationâThe Ad26.ZEBOV and MVA-BN-Filo Ebola vaccine regimen was well tolerated with no safety concerns in children aged 1â17 years, and induced robust humoral immune responses, suggesting suitability of this regimen for Ebola virus disease prophylaxis in children
Zementbildendes Fibrom des Siebbeins mit Einbruch in die Orbita
Einleitung: Das zementbildende Fibrom ist ein seltener, gutartiger, fibroössĂ€rer Tumor. In der ĂŒberwiegenden Anzahl der FĂ€lle geht diese ungewöhnliche Raumforderung von der Mandibula aus. Das Auftreten von zementbildenden Fibromen im Bereich des Siebbeines stellt eine RaritĂ€t dar.Patient und Ergebnis: Eine 16-jĂ€hrige Patientin stellte sich 1997 in unserer Poliklinik vor. Anamnestisch war ein Jahr zuvor erstmals ein Exophthalmus links aufgefallen. Der Visus war unauffĂ€llig, Doppelbilder bestanden nicht. Der HNO-Ă€rztliche Spiegelbefund war abgesehen von einer aufsteigenden Septumleiste links ohne pathologischen Befund. In der Computertomographie imponierte eine 4 x 3 cm groĂe, gut abgegrenzte Raumforderung im Bereich der linken Rhinobasis mit Einbruch in die linke Orbita. Wir fĂŒhrten eine transfaziale Tumorentfernung durch. Die Dura war intraoperativ teilweise freiliegend aber intakt. Der postoperative Verlauf war unauffĂ€llig. Im Februar 2010 stellte sich die Patientin mit einer Stirnhöhlenmukozele links erneut in unserem Hause vor. Wir fĂŒhrten eine transfaziale Stirnhöhlenoperation links durch. Weder der intraoperative Befund noch die Histopathologie ergaben einen Hinweis fĂŒr ein Rezidiv des zementbildenden Fibroms.Schlussfolgerung: Zementbildende Fibrome sind gutartige aber lokal aggressiv wachsende Tumoren der Periodontalmembran. Sie sind charakterisiert durch ein langsames, typischerweise schmerzloses Wachstum. Die differentialdiagnostische Abgrenzung zur fibrösen Dysplasie und zum Osteoblastom ist nur histopathologisch möglich. Die Therapie der Wahl des zementbildenden Fibroms ist die vollstĂ€ndige Exzision im Gesunden. Eine alleinige KĂŒrettage fĂŒhrt in der Regel zu einem Lokalrezidiv. Auf eine Radiatio spricht der Tumor nicht an
- âŠ