Scenarios for a post-COVID-19 world airline network.

The airline industry was severely hit by the COVID-19 crisis with an average demand decrease of about 64 % (IATA, April 2020), which triggered already several bankruptcies of airline companies all over the world. While the robustness of the world airline network (WAN) was mostly studied as a homogeneous network, we introduce a new tool for analyzing the impact of a company failure: the "airline company network" where two airlines are connected if they share at least one route segment. Using this tool, we observe that the failure of companies well connected with others has the largest impact on the connectivity of the WAN. We then explore how the global demand reduction affects airlines differently and provide an analysis of different scenarios if it stays low and does not come back to its pre-crisis level. Using traffic data from the Official Aviation Guide and simple assumptions about customer's airline choice strategies, we find that the local effective demand can be much lower than the average one, especially for companies that are not monopolistic and share their segments with larger companies. Even if the average demand comes back to 60 % of the total capacity, we find that between 46 % and 59 % of the companies could experience a reduction of more than 50 % of their traffic, depending on the type of competitive advantage that drives customer's airline choice. These results highlight how the complex competitive structure of the WAN weakens its robustness when facing such a large crisis.

Wiping conditions and fabric properties influenced the microfiber shedding from non-woven products.

Disposable wipes and masks have come to be considered as underestimated sources of microfiber generation since the emergence of COVID-19. However, research into the creation of microfibers due to wiping with these non-woven products is scarce, and the potential effects of fabric properties on shedding behavior are unclear. This study investigated microfiber release from 7 wet wipes, 5 dry wipes, and 4 masks in response to the use of simulated daily wiping conditions on artificial skin. The dry wipes (77-568 p per sheet) shed more microfibers than the wet ones (21-190 p per sheet) after 2, 10, or 50 wiping cycles under a 9.8 N wiping force. In addition, an average of 56 microfibers could be released from per gram of wipe, and each square centimeter of wipe could release about 1.18 microfibers during wiping. Masks shed fewer microfibers than wipes due to the excellent shedding resistance of spunbond nonwoven fabrics and the strengthened mechanical properties granted by bonding points. Cellulose, polyethylene terephthalate (PET), and polypropylene (PP) were the major polymers in the microfibers shed by wipes, and the microfibers from masks were all PP. With regard to the influencing factors, the number of microfibers shed from wipes was positively associated with the number of wiping cycles (r = 0.983 and 0.960, p < 0.01) and wiping force (r = 0.980, p < 0.05), while it was negatively correlated with the moisture content (r = -0.992, p < 0.01). Interestingly, a stronger fiber entanglement degree in the wipes significantly improved the resistance to microfiber generation (r = -0.664, p < 0.05). The results highlighted for the first time that the bending coefficient (ß = -5.05; 95% CI: -7.71, -2.40; p = 0.002) and fiber extraction force (ß = -0.077; 95% CI: -0.123, -0.030; p = 0.005) significantly reduced the tendency for microfiber shedding. Although the number of microfibers shed from wiping was lower than those from domestic washing, there is still an urgent need to control the microfiber shedding tendencies of non-woven products through improving the manufacturing processes.

The impact of COVID-19 on the worldwide air transportation network.

Air travel has been one of the hardest hit industries of COVID-19, with many flight cancellations and airport closures as a consequence. By analysing structural characteristics of the Official Aviation Guide flight data, we show that this resulted in an increased average distance between airports, and in an increased number of long-range routes. Based on our study of network robustness, we uncover that this disruption is consistent with the impact of a mixture of targeted and random global attack on the worldwide air transportation network. By considering the individual functional evolution of airports, we identify anomalous airports with high centrality but low degree, which further enables us to reveal the underlying transitions among airport-specific representations in terms of both geographical and geopolitical factors. During the evolution of the air transportation network, we also observe how the network attempted to cope by shifting centralities between different airports around the world. Since these shifts are not aligned with optimal strategies for minimizing delays and disconnects, we conclude that they are consistent with politics trumping science from the viewpoint of epidemic containment and transport.

Digital Transformation in Ophthalmic Clinical Care During the COVID-19 Pandemic.

ABSTRACT: COVID-19 has placed unprecedented pressure on health systems globally, whereas simultaneously stimulating unprecedented levels of transformation. Here, we review digital adoption that has taken place during the pandemic to drive improvements in ophthalmic clinical care, with a specific focus on out-of-hospital triage and services, clinical assessment, patient management, and use of electronic health records. We show that although there have been some successes, shortcomings in technology infrastructure prepandemic became only more apparent and consequential as COVID-19 progressed. Through our review, we emphasize the need for clinicians to better grasp and harness key technology trends such as telecommunications and artificial intelligence, so that they can effectively and safely shape clinical practice using these tools going forward.

Characteristics of endothelial corneal transplant rejection following immunisation with SARS-CoV-2 messenger RNA vaccine.

AIM: We report two cases of endothelial corneal allograft rejection following immunisation with SARS-CoV-2 messenger RNA (mRNA) vaccine BNT162b2 and describe the implications for management of transplant recipients postvaccination for COVID-19. METHODS: A 66-year-old woman with Fuchs endothelial corneal dystrophy (FECD) and a unilateral Descemet's membrane endothelial keratoplasty (DMEK) transplant received COVID-19 mRNA vaccine BNT162b2 14 days post-transplant. Seven days later, she presented with symptoms and signs of endothelial graft rejection. An 83-year-old woman with bilateral DMEK transplants for FECD 3 and 6 years earlier developed simultaneous acute endothelial rejection in both eyes, 3 weeks post second dose of COVID-19 mRNA vaccine BNT162b2. Rejection in both cases was treated successfully with topical corticosteroids. CONCLUSIONS: We believe this is the first report of temporal association between corneal transplant rejection following immunisation against COVID-19 and the first report of DMEK rejection following any immunisation. We hypothesise that the allogeneic response may have been initiated by the host antibody response following vaccination. Clinicians and patients should be aware of the potential of corneal graft rejection associated with vaccine administration and may wish to consider vaccination in advance of planned non-urgent keratoplasties. Patients should be counselled on the symptoms and signs that require urgent review to allow early treatment of any confirmed rejection episode.

Comprehensive evaluation of bronchoalveolar lavage from patients with severe COVID-19 and correlation with clinical outcomes.

Information on bronchoalveolar lavage (BAL) in patients with COVID-19 is limited, and clinical correlation has not been reported. This study investigated the key features of BAL fluids from COVID-19 patients and assessed their clinical significance. A total of 320 BAL samples from 83 COVID-19 patients and 70 non-COVID-19 patients (27 patients with other respiratory viral infections) were evaluated, including cell count/differential, morphology, flow cytometric immunophenotyping, and immunohistochemistry. The findings were correlated with clinical outcomes. Compared to non-COVID-19 patients, BAL from COVID-19 patients was characterized by significant lymphocytosis (p < 0.001), in contrast to peripheral blood lymphopenia commonly observed in COVID-19 patients and the presence of atypical lymphocytes with plasmacytoid/plasmablastic features (p < 0.001). Flow cytometry and immunohistochemistry demonstrated that BAL lymphocytes, including plasmacytoid and plasmablastic cells, were composed predominantly of T cells with a mixture of CD4+ and CD8+ cells. Both populations had increased expression of T-cell activation markers, suggesting important roles of helper and cytotoxic T-cells in the immune response to SARS-CoV-2 infection in the lung. More importantly, BAL lymphocytosis was significantly associated with longer hospital stay (p < 0.05) and longer requirement for mechanical ventilation (p < 0.05), whereas the median atypical (activated) lymphocyte count was associated with shorter hospital stay (p < 0.05), shorter time on mechanical ventilation (p < 0.05) and improved survival. Our results indicate that BAL cellular analysis and morphologic findings provide additional important information for diagnostic and prognostic work-up, and potential new therapeutic strategies for patients with severe COVID-19.

Safety of video-based telemedicine compared to in-person triage in emergency ophthalmology during COVID-19.

BACKGROUND: the need for social distancing midst the COVID-19 pandemic has forced ophthalmologists to innovate with telemedicine. The novel process of triaging emergency ophthalmology patients via videoconsultations should reduce hospital attendances. However, the safety profile of such services were unknown. METHODS: in this retrospective cohort study, we reviewed case notes of 404 adults who used our videoconsultation service from 20/04/2020 to 03/05/2020. We compared these to 451 patient who attended eye casualty in person at the same time who were deemed not to require same day ophthalmic examination. FINDINGS: patients seen by videoconsultations tended to be younger (Median = 43 years, Inter-quartile range = 27 vs Median= 49 years, Inter-quartile range = 28)'. More males used the face-to-face triage (55%) while more females used videoconsultation (54%)%. Fewer patients seen by videoconsultations required specialist review compared to face-face triage [X 2 (1, N = 854) = 128.02, p<0.001)]. 35.5% of the patients initially seen by videoconsultation had unplanned reattendance within 1 month, compared to 15.7% in the group initially seen in person. X 2 (1, N = 234) = 7.31, p = 0.007). The rate of actual harm was no different (at 0% for each method), with perfect inter-grader correlation when graded independently by two senior ophthalmologists. 97% of patients seen on the video platform surveyed were satisfied with their care. INTERPRETATION: we demonstrate comparable patient safety of videoconsultations at one-month follow-up to in person review. The service is acceptable to patients and reduces the risk of COVID-19 transmission. We propose that videoconsultations are effective and desirable as a tool for triage in ophthalmology. FUNDING: the research supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology who fund PT and DS's time to conduct research. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

[Annual progress in critical care medicine in 2020].

The epidemic of coronavirus disease 2019 (COVID-19) puts higher demands on critical care medicine. Lots of studies have been conducted to solve COVID-19-related problems. Therefore, we reviewed the annual progress for COVID-19-related issues including antivirals threapies, respiratory support and immunomodulatory therapies and other critical issues, including the effect of antibiotic on mitochondrial damage and its relationship with sepsis, the goal and direction of antimicrobial de-escalation, drug prophylaxis of constipation, bleeding in gastrointestinal disorders and management of critical illness in the informalization era and so on. We hope to provide reference for clinical and scientific research work of the intensivists.

Digital technology, tele-medicine and artificial intelligence in ophthalmology: A global perspective.

The simultaneous maturation of multiple digital and telecommunications technologies in 2020 has created an unprecedented opportunity for ophthalmology to adapt to new models of care using tele-health supported by digital innovations. These digital innovations include artificial intelligence (AI), 5th generation (5G) telecommunication networks and the Internet of Things (IoT), creating an inter-dependent ecosystem offering opportunities to develop new models of eye care addressing the challenges of COVID-19 and beyond. Ophthalmology has thrived in some of these areas partly due to its many image-based investigations. Tele-health and AI provide synchronous solutions to challenges facing ophthalmologists and healthcare providers worldwide. This article reviews how countries across the world have utilised these digital innovations to tackle diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration, glaucoma, refractive error correction, cataract and other anterior segment disorders. The review summarises the digital strategies that countries are developing and discusses technologies that may increasingly enter the clinical workflow and processes of ophthalmologists. Furthermore as countries around the world have initiated a series of escalating containment and mitigation measures during the COVID-19 pandemic, the delivery of eye care services globally has been significantly impacted. As ophthalmic services adapt and form a "new normal", the rapid adoption of some of telehealth and digital innovation during the pandemic is also discussed. Finally, challenges for validation and clinical implementation are considered, as well as recommendations on future directions.

Risk stratification of hospitalized COVID-19 patients through comparative studies of laboratory results with influenza.

BACKGROUND: The outbreak of coronavirus disease 2019 (COVID-19) in December 2019 overlaps with the flu season. METHODS: We compared clinical and laboratory results from 719 influenza and 973 COVID-19 patients from January to April 2020. We compiled laboratory results from the first 14 days of the hospitalized patients using parameters that are most significantly different between COVID-19 and influenza and hierarchically clustered COVID-19 patients. FINDINGS: Compared to influenza, patients with COVID-19 exhibited a continued increase in white blood cell count, rapid decline of hemoglobin, more rapid increase in blood urea nitrogen (BUN) and D-dimer, and higher level of alanine transaminase, C-reactive protein, ferritin, and fibrinogen. COVID-19 patients were sub-classified into 5 clusters through a hierarchical clustering analysis. Medical records were reviewed and patients were risk stratified based on the clinical outcomes. The cluster with the highest risk showed 27·8% fatality, 94% ICU admission, 94% intubation, and 28% discharge rates compared to 0%, 38%, 22%, and 88% in the lowest risk cluster, respectively. Patients in the highest risk cluster had leukocytosis including neutrophilia and monocytosis, severe anemia, increased red blood cell distribution width, higher BUN, creatinine, D-dimer, alkaline phosphatase, bilirubin, and troponin. INTERPRETATION: There are significant differences in the clinical and laboratory courses between COVID-19 and influenza. Risk stratification in hospitalized COVID-19 patients using laboratory data could be useful to predict clinical outcomes and pathophysiology of these patients. FUNDING: National Institute of Diabetes and Digestive and Kidney Disease, Department of Defense, and National Heart, Lung, and Blood Institute.

SARS-CoV-2 and the Eye: Implications for the Retina Specialist from Human Coronavirus Outbreaks and Animal Models.

PURPOSE: The current SARS-CoV-2 pandemic has escalated rapidly since December 2019. Understanding the ophthalmic manifestations in patients and animal models of the novel coronavirus may have implications for disease surveillance. Recognition of the potential for viral transmission through the tear film has ramification for protection of patients, physicians, and the public. METHODS: Information from relevant published journal articles was surveyed using a computerized PubMed search and public health websites. We summarize current knowledge of ophthalmic manifestations of SARS-CoV-2 infection in patients and animal models, risk mitigation measures for patients and their providers, and implications for retina specialists. RESULTS: SARS-CoV-2 is efficiently transmitted among humans, and while the clinical course is mild in the majority of infected patients, severe complications including pneumonia, acute respiratory distress syndrome, and death can ensue, most often in elderly patients and individuals with co-morbidities. Conjunctivitis occurs in a small minority of patients with COVID-19 and SARS-CoV-2 RNA has been identified primarily in association with conjunctivitis. Uveitis has been observed in animal models of coronavirus infection and cotton-wool spots have been reported recently. CONCLUSION: SARS-CoV-2 and other coronaviruses have been rarely associated with conjunctivitis. The identification of SARS-CoV and SARS-CoV-2 RNA in the tear film of patients and its highly efficient transmission via respiratory aerosols supports eye protection, mask and gloves as part of infection prevention and control recommendations for retina providers. Disease surveillance during the COVID-19 pandemic outbreak may also include ongoing evaluation for uveitis and retinal disease given prior findings observed in animal models and a recent report of retinal manifestations.

A data-driven assessment of early travel restrictions related to the spreading of the novel COVID-19 within mainland China.

Two months after it was firstly reported, the novel coronavirus disease COVID-19 spread worldwide. However, the vast majority of reported infections until February occurred in China. To assess the effect of early travel restrictions adopted by the health authorities in China, we have implemented an epidemic metapopulation model that is fed with mobility data corresponding to 2019 and 2020. This allows to compare two radically different scenarios, one with no travel restrictions and another in which mobility is reduced by a travel ban. Our findings indicate that i) travel restrictions might be an effective measure in the short term, however, ii) they are ineffective when it comes to completely eliminate the disease. The latter is due to the impossibility of removing the risk of seeding the disease to other regions. Furthermore, our study highlights the importance of developing more realistic models of behavioral changes when a disease outbreak is unfolding.