Assessing full thickness oral mucosal grafting: complications and postoperative outcomes in a broad collective of patients

Background: Conjunctival defects can be repaired with several mucosal tissues. The simplicity of harvesting oral mucosa and its wide availability makes it the preferred graft tissue for all indications requiring mucosal grafting. Through analysing the postsurgical outcomes and rate of revisions, this study explores the suitability of oral mucosa grafts, depending on the initial diagnosis. Methods: We reviewed all the files of patients with a history of oral mucosal graft surgery, performed at our clinic between 2012 and 2018, focusing on complications and revision rates. Results: In total, we analysed 173 oral mucosa grafts in 131 patients. The most common initial diagnosis was tumour resection, followed by surgical complications, postenucleation socket syndrome, trauma and ocular surface disorders. Complication and revision rates depended highly on the initial diagnosis. Revision rates were highest if the initial diagnosis included ocular surface disorders or chemical trauma. Conclusions: Oral mucosa grafting (OMG) is the most effective treatment for a wide range of ocular conditions involving conjunctival defects. Conjunctival defects that result from trauma or cicatricial surface diseases seem less suitable for OMG and may benefit from alternative graft tissue or treatment options

Exploring the precision of femtosecond laser-assisted descemetorhexis in Descemet membrane endothelial keratoplasty

Objective Descemet membrane endothelial keratoplasty (DMEK) remains a challenging technique. We compare the precision of femtosecond laser-assisted DMEK to manual DMEK. Methods and Analysis A manual descemetorhexis (DR) of 8 mm diameter was compared with a femtosecond laser-assisted DR of the same diameter (femto-DR) in 22 pseudophakic patients requiring DMEK. We used OCT images with a centred xy-diagram to measure the postoperative precision of the DR and the amount of endothelial denuded area. Endothelial cell loss (ECL) and best corrected visual acuity were measured 3 months after surgery. Results In the manual group, the median error of the DR was 7% (range 3%-16%) in the x-diameter and 8% (range 2%-17%) in the y-diameter. In the femto group, the median error in the respective x and y-diameters was 1% (range 0.4%-3%) and 1% (range 0.006%-2.5%), smaller than in the manual group (p=0.001). Endothelial denuded areas were larger in the manual group (11.6 mm(2), range 7.6-18 mm(2)) than in the femto group (2.5 mm(2), range 1.25.9 mm(2)) (p<0.001). The ECL was 21% (range 5%-78%) in the manual DR and 17% (range 6%-38%) in the femto-DR group (p=0.351). The median visual acuity increased from 0.4 logMAR (range 0.6-0.4 logMAR) in both groups to 0.1 logMAR (range 0.4-0 logMAR) in the manual group and to 0.1 logMAR (range 0.3-0 logMAR) in the femto group (p=0.461). Three rebubblings were required in the manual group, whereas the femto group required only one. Conclusion The higher precision of the femto-DR bears the potential to improve DMEK surgery

A multi-technology analysis of the 2017 North Korean nuclear test

On 3 September 2017 official channels of the Democratic People's Republic of Korea announced the successful test of a thermonuclear device. Only seconds to minutes after the alleged nuclear explosion at the Punggye-ri nuclear test site in the mountainous region in the country's northeast at 03:30:02 (UTC), hundreds of seismic stations distributed all around the globe picked up strong and distinct signals associated with an explosion. Different seismological agencies reported body wave magnitudes of well above 6.0, consequently estimating the explosive yield of the device on the order of hundreds of kT TNT equivalent. The 2017 event can therefore be assessed as being multiple times larger in energy than the two preceding North Korean events in January and September 2016. This study provides a multi-technology analysis of the 2017 North Korean event and its aftermath using a wide array of geophysical methods. Seismological investigations locate the event within the test site at a depth of approximately 0.6&thinsp;km below the surface. The radiation and generation of P- and S-wave energy in the source region are significantly influenced by the topography of the Mt. Mantap massif. Inversions for the full moment tensor of the main event reveal a dominant isotropic component accompanied by significant amounts of double couple and compensated linear vector dipole terms, confirming the explosive character of the event. The analysis of the source mechanism of an aftershock that occurred around 8&thinsp;min after the test in the direct vicinity suggest a cavity collapse. Measurements at seismic stations of the International Monitoring System result in a body wave magnitude of 6.2, which translates to an yield estimate of around 400&thinsp;kT TNT equivalent. The explosive yield is possibly overestimated, since topography and depth phases both tend to enhance the peak amplitudes of teleseismic P waves. Interferometric synthetic aperture radar analysis using data from the ALOS-2 satellite reveal strong surface deformations in the epicenter region. Additional multispectral optical data from the Pleiades satellite show clear landslide activity at the test site. The strong surface deformations generated large acoustic pressure peaks, which were observed as infrasound signals with distinctive waveforms even at distances of 401&thinsp;km. In the aftermath of the 2017 event, atmospheric traces of the fission product 133Xe were detected at various locations in the wider region. While for 133Xe measurements in September 2017, the Punggye-ri test site is disfavored as a source by means of atmospheric transport modeling, detections in October 2017 at the International Monitoring System station RN58 in Russia indicate a potential delayed leakage of 133Xe at the test site from the 2017 North Korean nuclear test.</p

A Comprehensive Study of Infrasound Signals Detected from the Ingolstadt, Germany, Explosion of 1 September 2018

The explosion at the Ingolstadt oil refinery was widely recorded at seismic and infrasound stations deployed throughout Central Europe, to distances of several hundred to a thousand kilometres. This study focuses on the wealth of data recorded at infrasound stations in Central and Eastern Europe, while from the many detecting seismic stations within 400 km range, only seismic and seismo-acoustic arrivals at the close-in Gräfenberg array are considered here. Most of the infrasound stations are acoustic arrays enabling us to apply array processing techniques to determine relevant wave field parameters, such as backazimuth and slowness (resp. trace velocity). These parameters not only confirm the source direction, but also put constraints on the observed arrivals’ propagation modes. Wave field parameters suggest that we observe tropospheric arrivals to about 150 km and stratospheric and/or thermospheric returns for longer distances. 1D, 2D and 3D ray tracing predict tropospheric arrivals to westerly directions up to distances of 100 km, beyond which only thermospheric returns are obtained azimuth-independent beyond 250–300 km. Stratospheric returns do not follow from any of the increasingly complex ray tracing models. Parabolic equation propagation modeling however suggests that in a number of cases stratospheric ducting may be possible. However, neither the tropospheric seismo-acoustic arrivals at the Gräfenberg array nor the various arrivals at IMS station IS26 could be modeled. Therefore, the Ingolstadt explosion along with the observed infrasonic phases provide an excellent test bed to investigate our ability in realistically forecasting atmospheric wave propagation with existing algorithms and available atmospheric models

Modellierung von Infraschall in der Atmosphäre: Auswirkungen auf die Mesopausentemperatur

Infraschall gehört zu den dynamischen Wellenvorgängen in der Atmosphäre, die das Druck- und Temperaurprofil beeinflussen. Infraschall wird erzeugt von einer ganzen Reihe natürlicher und künstlicher Quellen und kann zur Fernerkundung der Atmosphäre und der Überwachung von Naturgefahren und anthropogenen Signalen genutzt werden. Die Infraschallausbreitungsmodellierung mittels Ray-Tracing-Methoden unter Berücksichtigung atmosphärischer Hintergrundmodellierung wird in dieser Studie vorgestellt. Die Effekte von Infraschall in Temperaturfluktuationen und Heizraten werden quantifiziert und mit Zeitreihen der Mesopausentemperatur aus Airglow-Spektroskopie verglichen. Verschiedene Quellen von Infraschall beeinflussen das Temperaturprofil, daher werden erste Schritte zur Quellenunterscheidung und Mustererkennung von Infraschallsignaturen dargestellt. Vergleiche zu Airglow-Beobachtungen aus einem Zweijahreszeitraum mit verschiedenen Instrumenten zeigen das wahrscheinliche Auftreten von orographischen und meteorologischen Infraschallquellen wie Bergüberströmungen und Unwetter/Sturmsysteme