Automated, portable, and high-throughput fluorescence analyzer (APHF-analyzer) and lateral flow strip based on CRISPR/Cas13a for sensitive and visual detection of SARS-CoV-2.

COVID-19 has erupted and quickly swept across the globe, causing huge losses to human health and wealth. It is of great value to develop a quick, accurate, visual, and high-throughput detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we developed a biosensor based on CRISPR/Cas13a combined with recombinase polymerase amplification (RPA) to detect S and Orf1ab genes of SARS-CoV-2 within 30 min. Most important of all, we developed an automated, portable, and high-throughput fluorescence analyzer (APHF-analyzer) with a 3D-printed microfluidic chip for sensitively detecting SARS-CoV-2, which addressed aerosol contamination issue and provided a more accurate and high-throughput detection during the on-site detection process. The detection limits of S gene and Orf1ab gene were as low as 0.68 fM and 4.16 fM. Furthermore, we used the lateral flow strip to realize visualization and point of care testing (POCT) of SARS-CoV-2. Therefore, profit from the efficient amplification of RPA and the high specificity of CRISPR/Cas13a, APHF-analyzer and the lateral flow strip to simultaneous detection of S gene and Orf1ab gene would be applied as a promising tool in the field of SARS-CoV-2 detection.

Highly Transparent Nanofibrous Membranes Used as Transparent Masks for Efficient PM0.3 Removal.

Currently, the quest for highly transparent and flexible fibrous membranes with robust mechanical characteristics, high breathability, and good filtration performance is rapidly rising because of their potential use in the fields of electronics, energy, environment, medical, and health. However, it is still an extremely challenging task to realize transparent fibrous membranes due to serious surface light reflection and internal light scattering. Here, we report the design and development of a simple and effective topological structure to create porous, breathable, and high visible light transmitting fibrous membranes (HLTFMs). The resultant HLTFMs exhibit good optical performance (up to 90% transmittance) and high porosities (>80%). The formation of such useful structure with high light transmittance has been revealed by electric field simulation, and the mechanism of fibrous membrane structure to achieve high light transmittance has been proposed. Moreover, transparent masks have been prepared to evaluate the filtration performance and analyze their feasibility to meet requirement of facial recognition systems. The prepared masks display high transparency (>80%), low pressure drop (<100 Pa) and high filtration efficiency (>90%). Furthermore, the person wearing this mask can be successfully identified by facial recognition systems. Therefore, this work provides an idea for the development of transparent, breathable, and high-performance fibrous membranes.

Distinct Disease Severity Between Children and Older Adults With Coronavirus Disease 2019 (COVID-19): Impacts of ACE2 Expression, Distribution, and Lung Progenitor Cells.

BACKGROUND: Children and older adults with coronavirus disease 2019 (COVID-19) display a distinct spectrum of disease severity yet the risk factors aren't well understood. We sought to examine the expression pattern of angiotensin-converting enzyme 2 (ACE2), the cell-entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the role of lung progenitor cells in children and older patients. METHODS: We retrospectively analyzed clinical features in a cohort of 299 patients with COVID-19. The expression and distribution of ACE2 and lung progenitor cells were systematically examined using a combination of public single-cell RNA-seq data sets, lung biopsies, and ex vivo infection of lung tissues with SARS-CoV-2 pseudovirus in children and older adults. We also followed up patients who had recovered from COVID-19. RESULTS: Compared with children, older patients (>50 years.) were more likely to develop into serious pneumonia with reduced lymphocytes and aberrant inflammatory response (P = .001). The expression level of ACE2 and lung progenitor cell markers were generally decreased in older patients. Notably, ACE2 positive cells were mainly distributed in the alveolar region, including SFTPC positive cells, but rarely in airway regions in the older adults (P < .01). The follow-up of discharged patients revealed a prolonged recovery from pneumonia in the older (P < .025). CONCLUSIONS: Compared to children, ACE2 positive cells are generally decreased in older adults and mainly presented in the lower pulmonary tract. The lung progenitor cells are also decreased. These risk factors may impact disease severity and recovery from pneumonia caused by SARS-Cov-2 infection in older patients.

Factors associated with the time to return negative RT-PCR from COVID-19 in paediatric patients: a retrospective cohort study.

OBJECTIVE: This study aimed to describe the epidemiological and clinical features and potential factors related to the time to return negative reverse transcriptase (RT)-PCR in discharged paediatric patients with COVID-19. DESIGN: Retrospective cohort study. SETTING: Unscheduled admissions to 12 tertiary hospitals in China. PARTICIPANTS: Two hundred and thirty-three clinical charts of paediatric patients with confirmed diagnosis of COVID-19 admitted from 1 January 2020 to 17 April 2020. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome measures: factors associated with the time to return negative RT-PCR from COVID-19 in paediatric patients. SECONDARY OUTCOME MEASURES: epidemiological and clinical features and laboratory results in paediatric patients. RESULTS: The median age of patients in our cohort was 7.50 (IQR: 2.92-12.17) years, and 133 (57.1%) patients were male. 42 (18.0%) patients were evaluated as asymptomatic, while 162 (69.5%) and 25 (10.7%) patients were classified as mild or moderate, respectively. In Cox regression analysis, longer time to negative RT-PCR was associated with the presence of confirmed infection in family members (HR (95% CI): 0.56 (0.41 to 0.79)). Paediatric patients with emesis symptom had a longer time to return negative (HR (95% CI): 0.33 (0.14 to 0.78)). During hospitalisation, the use of traditional Chinese medicine (TCM) and antiviral drugs at the same time is less conducive to return negative than antiviral drugs alone (HR (95% CI): 0.85 (0.64 to 1.13)). CONCLUSIONS: The mode of transmission might be a critical factor determining the disease severity of COVID-19. Patients with emesis symptom, complications or confirmed infection in family members may have longer healing time than others. However, there were no significant favourable effects from TCM when the patients have received antiviral treatment.

Water electret charging based polypropylene/electret masterbatch composite melt-blown nonwovens with enhanced charge stability for efficient air filtration

With rapidly increasing demand for clean air, especially in this covid era, high efficiency filtration materials have gained massive significance and have become need of the hour. Currently, corona-electret-based filtration materials are the most used filtration materials. However, their instability in hot and humid environment demands for designing better and stable alternative filtration materials. Herein, we report novel electret polypropylene/electret masterbatch (PP-EM) composite melt-blown nonwovens with enhanced charge stability using water electret charging (WEC). WEC based nonwovens not only display improved the filtration efficiency (99.3%) but also offer tuned pore size to reduce the pressure drop from 71.6 Pa to 63.2 Pa. Significantly, the micro mechanism of triboelectric initiation between single fiber and deionized water in WEC has also been proposed. Benefiting from the process of charging by friction and hot air drying, the charge stored inside the fibers is insensitive to temperature and humidity. The successful fabrication of WEC PP-EM composite melt-blown nonwovens paves the pathway forward for the design and development of air filters with reinforced charge stability.

Epidemiological characteristics and clinical manifestations of pediatric patients with COVID-19 in China: A multicenter retrospective study.

Importance: The Coronavirus disease 2019 (COVID-19) global pandemic poses a considerable challenge for pediatricians. Objective: This study aimed to identify the epidemiological characteristics and clinical features of pediatric patients with COVID-19 in China. Methods: This multicenter retrospective study included pediatric patients from 46 hospitals in China, covering 12 provinces and two municipalities. Epidemiological, demographic, clinical, laboratory, treatment, and outcome data were analyzed. Results: In total, 211 pediatric patients with COVID-19 were included in this study. The median age was 7.0 years (range: 22 days to 18 years). Approximately 16.3% of the patients exhibited asymptomatic infections, 23.0% had upper respiratory tract infections, and 60.7% had pneumonia, including two with severe pneumonia and one with critical illness. Approximately 78.7% of the pediatric patients occurred in familial clusters. The most three common symptoms or signs at onset in children with COVID-19 were fever (54.5%), cough (49.3%), and pharyngeal congestion (20.8%). Only 17.6% of the patients presented with decreased lymphocyte count, whereas 13.6% had increased lymphocyte count. Among the patients with pneumonia who exhibited abnormal chest computed tomography findings, 18.2% (23/127) of the patients had no other symptoms. Generally, the chest radiographs showed abnormalities that affected both lungs (49.6%); ground-glass opacity (47.2%) was the most common manifestation. The cure and improvement rates were 86.7% (183/211) and 13.3% (28/211), respectively. Only one patient with an underlying condition received invasive mechanical ventilation; none of the patients died. Interpretation: Similar to adults, children of all age groups are susceptible to COVID-19. Fortunately, most pediatric patients have mild symptoms or remain asymptomatic, despite the high incidence of pneumonia. Decreased proportions of white blood cells and lymphocytes are less frequent in children than in adults.

China’s International Liner Shipping Network Evolution and Vulnerability Based on Automatic Identification System (AIS) Data

Container shipping network is an important basis for global manufacturing and supply chain operation. China’s international liner shipping network has become one of the most essential sub-networks of the global container shipping network. Based on ship Automatic Identification System (AIS) data, this paper calculated the leading indicators of complex networks of China’s international liner shipping network, the Belt and Road network, the China-US network, and the China-Africa network. Analyzed the network characteristics, port importance, and network evolution and vulnerability. The study found that, from 2016 to 2019, the scope of China’s international liner shipping network was expanded. The number of nodes increased from 468 to 622, and the efficiency of the network has increased by 7.8%. In the meantime, the importance of ports in the network has changed, as Busan replaced Singapore as the highest connectivity node of China's container shipping network. Moreover, the paralysis of Busan, Singapore, Hong Kong, Antwerp, and Port Said has a significant impact on China's foreign trade route network transportation. This study helps us to assess the vulnerability of shipping networks under the impact of COVID-19 and provides useful Suggestions for maintaining global supply chain security.

Comparison of Clinical Characteristics Among COVID-19 and Non-COVID-19 Pediatric Pneumonias: A Multicenter Cross-Sectional Study.

Background: The pandemic of Coronavirus Disease 2019 (COVID-19) brings new challenges for pediatricians, especially in the differentiation with non-COVID-19 pneumonia in the peak season of pneumonia. We aimed to compare the clinical characteristics of pediatric patients with COVID-19 and other respiratory pathogens infected pneumonias. Methods: We conducted a multi-center, cross-sectional study of pediatric inpatients in China. Based on pathogenic test results, pediatric patients were divided into three groups, including COVID-19 pneumonia group, Non-COVID-19 viral (NCV) pneumonia group and Non-viral (NV) pneumonia group. Their clinical characteristics were compared by Kruskal-Wallis H test or chi-square test. Results: A total of 636 pediatric pneumonia inpatients, among which 87 in COVID-19 group, 194 in NCV group, and 355 in NV group, were included in analysis. Compared with NCV and NV patients, COVID-19 patients were older (median age 6.33, IQR 2.00-12.00 years), and relatively fewer COVID-19 patients presented fever (63.2%), cough (60.9%), shortness of breath (1.1%), and abnormal pulmonary auscultation (18.4%). The results were verified by the comparison of COVID-19, respiratory syncytial virus (RSV) and influenza A (IFA) pneumonia patients. Approximately 42.5%, 44.8%, and 12.6% of the COVID-19 patients presented simply ground-glass opacity (GGO), simply consolidation, and the both changes on computed tomography (CT) scans, respectively; the proportions were similar as those in NCV and NV group (p>0.05). Only 47.1% of COVID-19 patients had both lungs pneumonia, which was significantly lower than that proportion of nearly 80% in the other two groups. COVID-19 patients presented lower proportions of increased white blood cell count (16.5%) and abnormal procalcitonin (PCT) (10.7%), and a higher proportion of decreased lymphocyte count (44.0%) compared with the other two groups. Conclusion: Majority clinical characteristics of pediatric COVID-19 pneumonia patients were milder than non-COVID-19 patients. However, lymphocytopenia remained a prominent feature of COVID-19 pediatric pneumonia.

A comparative study of SARS-CoV-2 nucleic acid assay for nasal swab and sputum samples

Objective: To analyze nucleic acid detection results of coronavirus disease 2019 (COVID-19) patients' nasal swabs and sputum specimens, and we provide reference for clinical sampling methods.

Comparison of clinical features on admission between coronavirus disease 2019 and influenza a among children: a retrospective study in China.

BACKGROUND: Coronavirus disease 2019 (COVID-19) share similar symptoms with influenza A (IA), but it is more worthwhile to understand the disparities of the two infections regarding their clinical characteristics on admission. METHODS: A total of 71 age-matched pediatric IA and COVID-19 patient pairs were formed and their clinical data on admission were compared. RESULTS: Fever, cough, nasal congestion and nausea/vomiting were the most common symptoms on admission for both infections but occurred less often in COVID-19. The IA patients were more likely to have lower-than-normal levels of lymphocyte count and percentage and to have higher-than-normal levels of activated partial thromboplastin time, prothrombin time, serum C-reactive protein, and serum procalcitonin, while the COVID-19 patients had higher odds of having lower-than-normal levels of neutrophil count and percentage. CONCLUSIONS: This study suggests that influenza A is more symptomatic than COVID-19 for children and might be an overall more severe infection at the time of admission.

Comparison of acute pneumonia caused by SARS-COV-2 and other respiratory viruses in children: a retrospective multi-center cohort study during COVID-19 outbreak.

BACKGROUND: Until January 18, 2021, coronavirus disease-2019 (COVID-19) has infected more than 93 million individuals and has caused a certain degree of panic. Viral pneumonia caused by common viruses such as respiratory syncytial virus, rhinovirus, human metapneumovirus, human bocavirus, and parainfluenza viruses have been more common in children. However, the incidence of COVID-19 in children was significantly lower than that in adults. The purpose of this study was to describe the clinical manifestations, treatment and outcomes of COVID-19 in children compared with those of other sources of viral pneumonia diagnosed during the COVID-19 outbreak. METHODS: Children with COVID-19 and viral pneumonia admitted to 20 hospitals were enrolled in this retrospective multi-center cohort study. A total of 64 children with COVID-19 were defined as the COVID-19 cohort, of which 40 children who developed pneumonia were defined as the COVID-19 pneumonia cohort. Another 284 children with pneumonia caused by other viruses were defined as the viral pneumonia cohort. The epidemiologic, clinical, and laboratory findings were compared by Kolmogorov-Smirnov test, t-test, Mann-Whitney U test and Contingency table method. Drug usage, immunotherapy, blood transfusion, and need for oxygen support were collected as the treatment indexes. Mortality, intensive care needs and symptomatic duration were collected as the outcome indicators. RESULTS: Compared with the viral pneumonia cohort, children in the COVID-19 cohort were mostly exposed to family members confirmed to have COVID-19 (53/64 vs. 23/284), were of older median age (6.3 vs. 3.2 years), and had a higher proportion of ground-glass opacity (GGO) on computed tomography (18/40 vs. 0/38, P < 0.001). Children in the COVID-19 pneumonia cohort had a lower proportion of severe cases (1/40 vs. 38/284, P = 0.048), and lower cases with high fever (3/40 vs. 167/284, P < 0.001), requiring intensive care (1/40 vs. 32/284, P < 0.047) and with shorter symptomatic duration (median 5 vs. 8 d, P < 0.001). The proportion of cases with evaluated inflammatory indicators, biochemical indicators related to organ or tissue damage, D-dimer and secondary bacterial infection were lower in the COVID-19 pneumonia cohort than those in the viral pneumonia cohort (P < 0.05). No statistical differences were found in the duration of positive PCR results from pharyngeal swabs in 25 children with COVID-19 who received antiviral drugs (lopinavir-ritonavir, ribavirin, and arbidol) as compared with duration in 39 children without antiviral therapy [median 10 vs. 9 d, P = 0.885]. CONCLUSION: The symptoms and severity of COVID-19 pneumonia in children were no more severe than those in children with other viral pneumonia. Lopinavir-ritonavir, ribavirin and arbidol do not shorten the duration of positive PCR results from pharyngeal swabs in children with COVID-19. During the COVID-19 outbreak, attention also must be given to children with infection by other pathogens infection.

Clinical analysis and pluripotent stem cells-based model reveal possible impacts of ACE2 and lung progenitor cells on infants vulnerable to COVID-19.

Introduction: An increasing number of children with severe coronavirus disease 2019 (COVID-19) is being reported, yet the spectrum of disease severity and expression patterns of angiotensin-converting enzyme 2 (ACE2) in children at different developmental stages are largely unknow. Methods: We analysed clinical features in a cohort of 173 children with COVID-19 (0-15 yrs.-old) between January 22, 2020 and March 15, 2020. We systematically examined the expression and distribution of ACE2 in different developmental stages of children by using a combination of children's lung biopsies, pluripotent stem cell-derived lung cells, RNA-sequencing profiles, and ex vivo SARS-CoV-2 pseudoviral infections. Results: It revealed that infants (< 1yrs.-old), with a weaker potency of immune response, are more vulnerable to develop pneumonia whereas older children (> 1 yrs.-old) are more resistant to lung injury. The expression levels of ACE2 however do not vary by age in children's lung. ACE2 is notably expressed not only in Alveolar Type II (AT II) cells, but also in SOX9 positive lung progenitor cells detected in both pluripotent stem cell derivatives and infants' lungs. The ACE2+SOX9+ cells are readily infected by SARS-CoV-2 pseudovirus and the numbers of the double positive cells are significantly decreased in older children. Conclusions: Infants (< 1 yrs.-old) with SARS-CoV-2 infection are more vulnerable to lung injuries. ACE2 expression in multiple types of lung cells including SOX9 positive progenitor cells, in cooperation with an unestablished immune system, could be risk factors contributing to vulnerability of infants with COVID-19. There is a need to continue monitoring lung development in young children who have recovered from SARS-CoV-2 infection.

Comparative analysis of clinical features of SARS-CoV-2 and adenovirus infection among children.

BACKGROUND: The new emerging coronavirus disease 2019 (COVID-19) overall shares similar symptoms with other common respiratory viral infections. We aimed in this study to compare COVID-19 and human adenovirus (HAdV) infections in pediatric patients regarding the frequencies of major clinical symptoms and the potential disparities in laboratory and imaging parameters. METHODS: Following a case-control-like design, we built 72 age-matched pediatric COVID-19 and HAdV patient pairs. Their early symptoms and laboratory and imaging characteristics were then retrieved and compared. RESULTS: Fever and cough were the most common symptoms for both infections but were seen more often in HAdV than in COVID-19 patients (92% vs. 66% and 60% vs. 18%, respectively). Compared with COVID-19 patients, children with HAdV infection had statistically significantly higher values of neutrophil count, neutrophil percentage, activated partial thromboplastin time, prothrombin time, lactate dehydrogenase, C-reactive protein, procalcitonin but lower values of lymphocyte percentage, total bilirubin, potassium and sodium. Thoracic computed tomography also revealed more anomalies in HAdV patients than in COVID-19 patients (95% vs. 67%). CONCLUSIONS: COVID-19 is an overall less symptomatic and less severe infection at admission compared to HAdV respiratory infection in pediatric population.

Clinical Outcomes in 55 Patients With Severe Acute Respiratory Syndrome Coronavirus 2 Who Were Asymptomatic at Hospital Admission in Shenzhen, China.

An epidemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has spread unexpectedly in Wuhan, Hubei Province, China, since December 2019. There are few reports about asymptomatic contacts of infected patients identified as positive for SARS-CoV-2 through screening. We studied the epidemiological and clinical outcomes in 55 asymptomatic carriers who were laboratory confirmed to be positive for SARS-CoV-2 through nucleic acid testing of pharyngeal swab samples. The asymptomatic carriers seldom occurred among young people (aged 18-29 years) who had close contact with infected family members. In the majority of patients, the outcome was mild or ordinary 2019 novel coronavirus disease during hospitalization.