A Nationwide Study on the Impact of COVID-19 Pandemic on Volume of Spine Surgery in South Korea

ObjectiveIn March 2020, World Health Organization declared a global pandemic caused by a novel coronavirus (SARS-CoV-2). The disease caused by this virus is called COVID-19. Due to its high contagiousness, many changes have occurred in overall areas of our daily life including hospital use by patients. The aim of this study was to investigate the impact of COVID-19 on volume of spine surgery in South Korea using the National Health Insurance database and compare it with the volume of a homologous period before the pandemic. MethodsData of related to spine surgery from January 2019 to April 2021 were obtained from the National Health Insurance and Health Insurance Review and Assessment Service database. Primary outcomes were total number of patients, rate of patients per 100000 population, and total number of procedures. The number of patients by hospital size was also analyzed. ResultsCOVID-19 outbreaks occurred in South Korea in March, August, and December of 2020. Compared to the previous year, the total number of patients who underwent spinal surgery showed a decrease for 2–3 months after the first and second outbreaks. However, it showed an increasing trend after the third outbreak. The same pattern was observed in terms of the ratio of the number of patients per 100000 population. Between 2019 and 2021, the mean number of spine surgeries per month tended to increase. Mean annual medical expenses increased over the years (p=0.001). When the number of spine surgeries was analyzed by hospital size, proportion of tertiary general hospital in 2021 increased compared to those in 2019 and 2020 (vs. 2019, p=0.012; vs. 2020, p=0.016). The proportion of general hospital was significantly decreased in 2020 compared to that in 2019 (p=0.037). ConclusionAfter the COVID-19 outbreak, patients tended to postpone spinal surgery temporarily. The number of spinal surgeries decreased for 2–3 months after the first and second outbreaks. However, as the ability to respond to the COVID-19 pandemic at the hospital and society-wide level gradually increased, the number of spine surgeries did not decrease after the third outbreak in December 2020. In addition, the annual number of spine surgeries continued to increase. However, it should be noted that patients tend to be increasingly concentrated in tertiary hospitals for spinal surgery.     

Improving the Performance of Solution−Processed Quantum Dot Light−Emitting Diodes via a HfOx Interfacial Layer

One of the major obstacles in the way of high−performance quantum dot light−emitting diodes (QLEDs) is the charge imbalance arising from more efficient electron injection into the emission layer than the hole injection. In previous studies, a balanced charge injection was often achieved by lowering the electron injection efficiency; however, high performance next−generation QLEDs require the hole injection efficiency to be enhanced to the level of electron injection efficiency. Here, we introduce a solution−processed HfO_x layer for the enhanced hole injection efficiency. A large amount of oxygen vacancies in the HfO_x films creates gap states that lower the hole injection barrier between the anode and the emission layer, resulting in enhanced light−emitting characteristics. The insertion of the HfO_x layer increased the luminance of the device to 166,600 cd/m², and the current efficiency and external quantum efficiency to 16.6 cd/A and 3.68%, respectively, compared with the values of 63,673 cd/m², 7.37 cd/A, and 1.64% for the device without HfO_x layer. The enhanced light−emitting characteristics of the device were elucidated by X−ray photoelectron, ultra−violet photoelectron, and UV−visible spectroscopy. Our results suggest that the insertion of the HfO_x layer is a useful method for improving the light−emitting properties of QLEDs.     

Improved Bone Conduction Hearing After Middle Ear Surgery: Investigation of the Improvement Mechanism

Objectives. When performing middle ear operations, such as ossiculoplasty or stapes surgery, patients and surgeons expect an improvement in air conduction (AC) hearing, but generally not in bone conduction (BC). However, BC improvement has often been observed after surgery, and the present study investigated this phenomenon.Methods. We reviewed the preoperative and postoperative surgical outcomes of 583 patients who underwent middle ear surgery. BC improvement was defined as a BC threshold decrease of >15 dB at two or more frequencies. Subjects in group A underwent staged ossiculoplasty after canal wall up mastoidectomy (CWUM), group B underwent staged ossiculoplasty after canal wall down mastoidectomy (CWDM), group C underwent ossiculoplasty only (thus, they had no prior history of CWUM or CWDM), and group D received stapes surgery. We created a hypothetical circuit model to explain this phenomenon.Results. BC improvement was detected in 12.8% of group A, 9.1% of group B, and 8.5% of group C. The improvement was more pronounced in group D (27.0%). A larger gain in AC hearing was weakly correlated with greater BC improvement (Pearson’s r=0.395 in group A, P<0.001; r=0.375 in group B, P<0.001; r=0.296 in group C, P<0.001; r=0.422 in group D, P=0.009). Notably, patients with otosclerosis even experienced postoperative BC improvements as large as 10.0 dB, from a mean value of 30.3 dB (standard error [SE], 3.2) preoperatively to 20.3 dB (SE, 3.2) postoperatively, at 1,000 Hz, as well as an improvement of 9.2 dB at 2,000 Hz, from 37.8 dB (SE, 2.6) to 28.6 dB (SE, 3.1).Conclusion. BC improvement may be explained by a hypothetical circuit model applying the third window theory. Surgeons should keep in mind the possibility of BC improvement when making a management plan.     

Staubmasken und Staubfilter. Ihre Wirksamkeit und ihr Atemwiderstand. Grenzen ihrer Anwendbarkeit in Betrieben der Industrie der Steine und Erden

Ohne Zusammenfassung     

Beiträge zur Perniziösen Anämie der Ratten

Zusammenfassung Aus Catania nach Wien übersandte und hier splenektomierte Tiere blieben während einer langdauernden Beobachtung gesund und bartonellenfrei, sie erkrankten in gleicher Weise wie Wiener Ratten nach künstlicher Überimpfung von infektiösem Organbrei oder nach experimenteller Stallinfektion. Milzhaltige italienische Ratten blieben vor der Erkrankung trotz künstlicher Infektion verschont.Aus Wien nach Catania übersandte Ratten erkrankten nach Splenektomie unter dem Zeichen der perniziösen Anämie der Ratte, gleichzeitig entmilzte italienische Kontrollratten blieben gesund. Mit infektiösem Organbrei perniziös anämisch verendeter Wiener Tiere konnten ohne weiteres Passagen auf entmilzte italienische Ratten angelegt werden.Die seinerzeitigen widersprechenden Versuchsresultate vonLauda einerseits undSorge andererseits erscheinen durch die vorliegenden Untersuchungen eindeutig dadurch geklärt, daß die Wiener Rattenbestände zum größten Teil mit Bartonella muris ratti durchseucht, die italienischen Ratten dagegen nicht durchseucht sind.