Economic and environmental benefits of automated electric vehicle ride-hailing services in New York City.

A precise, scalable, and computationally efficient mathematical framework is proposed for region-wide autonomous electric vehicle (AEV) fleet management, sizing and infrastructure planning for urban ride-hailing services. A comprehensive techno-economic analysis in New York City is conducted not only to calculate the societal costs but also to quantify the environmental and health benefits resulting from reduced emissions. The results reveal that strategic fleet management can reduce fleet size and unnecessary cruising mileage by up to 40% and 70%, respectively. This alleviates traffic congestion, saves travel time, and further reduces fleet sizes. Besides, neither large-battery-size AEVs nor high-power charging infrastructure is necessary to achieve efficient service. This effectively alleviates financial and operational burdens on fleet operators and power systems. Moreover, the reduced travel time and emissions resulting from efficient fleet autonomy create an economic value that exceeds the total capital investment and operational costs of fleet services.

Magnetic Janus origami robot for cross-scale droplet omni-manipulation.

The versatile manipulation of cross-scale droplets is essential in many fields. Magnetic excitation is widely used for droplet manipulation due to its distinguishing merits. However, facile magnetic actuation strategies are still lacked to realize versatile multiscale droplet manipulation. Here, a type of magnetically actuated Janus origami robot is readily fabricated for versatile cross-scale droplet manipulation including three-dimensional transport, merging, splitting, dispensing and release of daughter droplets, stirring and remote heating. The robot allows untethered droplet manipulation from ~3.2 nL to ~51.14 µL. It enables splitting of droplet, precise dispensing (minimum of ~3.2 nL) and release (minimum of ~30.2 nL) of daughter droplets. The combination of magnetically controlled rotation and photothermal properties further endows the robot with the ability to stir and heat droplets remotely. Finally, the application of the robot in polymerase chain reaction (PCR) is explored. The extraction and purification of nucleic acids can be successfully achieved.

Hsa_circ_0041150 serves as a novel biomarker for monitoring chemotherapy resistance in small cell lung cancer patients treated with a first-line chemotherapy regimen.

PURPOSE: To explore the potential of circRNAs as biomarkers in non-invasive body fluids for monitoring chemotherapy resistance in SCLC patients. METHODS: CircRNAs were screened and characterized using transcriptome sequencing, Sanger sequencing, actinomycin D treatment, and Ribonuclease R assay. Our study involved 174 participants, and serum samples were collected from all chemotherapy-resistant patients (n = 54) at two time points: stable disease and progressive disease. We isolated and identified serum extracellular vesicles (EVs) from the patients using ultracentrifugation, transmission electron microscopy, nanoflow cytometry, and western blotting analysis. The expression levels of serum and serum EVs circRNAs were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The impact of circRNA on the function of SCLC cells was assessed through various assays, including proliferation assay, scratch assay, transwell assay, and cisplatin resistance assay. RESULTS: Hsa_circ_0041150 was found to be upregulated in chemoresistant SCLC cells and played a role in promoting proliferation, invasion, migration, and cisplatin resistance. Furthermore, the expression levels of hsa_circ_0041150 in serum and serum EVs increased when SCLC patients developed resistance after a first-line chemotherapy regimen. When combined with NSE, the monitoring sensitivity (70.37%) and specificity (81.48%) for chemotherapy resistance significantly improved. Moreover, the expression level of hsa_circ_0041150 showed significant associations with time to progression from SD to PD, and high hsa_circ_0041150 levels after drug resistance were more likely to cause chemotherapy resistance. Additionally, hsa_circ_0041150 demonstrated valuable potential in monitoring the progression from initial diagnosis to chemotherapy resistance in SCLC patients. CONCLUSION: Thus, EVs hsa_circ_0041150 holds promise as a biomarker for monitoring chemotherapy resistance in SCLC patients.

Parthenolide targets NLRP3 to treat inflammasome-related diseases.

Natural products have attracted extensive attention from researchers in medical fields due to their abundant biological activities. Parthenolide (PTL) is a sesquiterpene lactone originally purified from herb Feverfew (Tanacetum parthenium), recent studies have showed its potential activities of anti-cancer and anti-inflammatory. Acting as the most studied inflammasome, NLRP3 inflammasome played an important role in human diseases including type-2 diabetes (T2D), Alzheimer's disease (AD) and cryopyrin-associated periodic syndromes (CAPS). In this article, we show that PTL specially inhibits the activation of NLRP3 inflammation by block the upstream signal and prevent the assembly of NLRP3 inflammasome complex. Furthermore, we showed the treatment of PTL significantly attenuates the symptoms of lipopolysaccharide (LPS)-induced systemic inflammation and dextran sulfate sodium (DSS)-induced colitis in mice models. Thus, our results demonstrate that PTL alleviates inflammation by targeting NLRP3 inflammasome, which indicate that PTL acting as a promising natural product for the treatment of NLRP3 inflammasome-related diseases.

Identification of hsa-miR-619-5p and hsa-miR-4454 in plasma-derived exosomes as a potential biomarker for lung adenocarcinoma.

Introduction: Lung cancer has long been at the forefront of all cancers in terms of incidence and mortality. Lung adenocarcinoma is the most common type of lung cancer, accounting for 40% of all lung cancer types. Exosomes can act as biomarkers of tumors and thus play an important role. Methods: In this article, high-throughput sequencing of miRNAs in plasma exosomes from lung adenocarcinoma patients and healthy individuals was performed to obtain 87 upregulated miRNAs, which were then combined with data from the GSE137140 database uploaded by others for screening. The database included 1566 preoperative lung cancer patients, 180 postoperative patients, and 1774 non-cancerous controls. We overlapped the miRNAs upregulated in the serum of lung cancer patients in the database relative to those of non-cancer controls and post-operative patients with the upregulated miRNAs obtained from our next-generation sequencing to obtain nine miRNAs. Two miRNAs that were not reported as tumor markers in lung cancer, hsa-miR-4454 and hsa-miR-619-5p, were selected from them and then validated by qRT-PCR, and further analysis of miRNAs was performed using bioinformatics. Results: Real-time quantitative PCR showed that the expression levels of hsa-miR-4454 and hsa-miR-619-5p in plasma exosomes of patients with lung adenocarcinoma were significantly up-regulated. The AUC values of hsa-miR-619-5p and hsa-miR-4454 were 0.906 and 0.975, respectively, both greater than 0.5, showing good performance. The target genes of miRNAs were screened by bioinformatics methods, and the regulatory network between miRNAs and lncRNAs and mRNAs was studied. Discussion: Our work demonstrated that hsa-miR-4454 and hsa-miR-619-5p have the potential to be used as biomarkers for the early diagnosis of lung adenocarcinoma.

High-performance blood plasma separation based on a Janus membrane technique and RBC agglutination reaction.

Separation of plasma which is full of various biomarkers is critical for clinical diagnosis. However, the point-of-care plasma separation often relies on microfluidic filtration membranes which are usually limited in purity, yield, hemolysis, extraction speed, hematocrit level, and protein recovery. Here, we have developed a high-performance plasma membrane separation technique based on a Janus membrane and red blood cell (RBC) agglutination reaction. The RBC agglutination reaction can form larger RBC aggregates to separate plasma from blood cells. Then, the Janus membrane, serving as a multipore microfilter to block large RBC aggregates, allows the plasma to flow from the hydrophobic side to its hydrophilic side spontaneously. As a result, the separation technique can extract highly-purified plasma (99.99%) from whole blood with an ultra-high plasma yield (∼80%) in ∼80 s. Additionally, the separation technique is independent of the hematocrit level and can avoid hemolysis.

Structural insights into human CCAN complex assembled onto DNA.

In mitosis, accurate chromosome segregation depends on kinetochores that connect centromeric chromatin to spindle microtubules. The centromeres of budding yeast, which are relatively simple, are connected to individual microtubules via a kinetochore constitutive centromere associated network (CCAN). However, the complex centromeres of human chromosomes comprise millions of DNA base pairs and attach to multiple microtubules. Here, by use of cryo-electron microscopy and functional analyses, we reveal the molecular basis of how human CCAN interacts with duplex DNA and facilitates accurate chromosome segregation. The overall structure relates to the cooperative interactions and interdependency of the constituent sub-complexes of the CCAN. The duplex DNA is topologically entrapped by human CCAN. Further, CENP-N does not bind to the RG-loop of CENP-A but to DNA in the CCAN complex. The DNA binding activity is essential for CENP-LN localization to centromere and chromosome segregation during mitosis. Thus, these analyses provide new insights into mechanisms of action underlying kinetochore assembly and function in mitosis.

Ultrathin silicon nitride membrane with slit-shaped pores for high-performance separation of circulating tumor cells.

In this study, we developed an ultrathin filtering membrane with slit-shaped pores which can achieve circulating tumor cell (CTC) separation from whole blood with high performance (high capture efficiency, high white blood cell (WBC) depletion, and high viability). The silicon nitride (Si3N4) filtering membrane was fabricated via the standard microfabrication technology, which can be easily scaled up to mass-production. 6 µm was determined as the optimum width of the filtering pores to better separate CTCs in whole blood, which can reach a high capture efficiency of ∼96%. Meanwhile, the filtering membrane with a high porosity of 34% demonstrated high WBC depletion (∼99.99%). Furthermore, the ultrathin (thickness: 200 nm) Si3N4 membrane facilitated the capture of CTCs with high viability (∼90%). Finally, the microfluidic chip was successfully applied to separate CTCs in whole blood samples from cancer patients and used for molecular examination. These results indicate that this microfluidic chip facilitates the clinical application of CTC-based liquid biopsy technology.

Ultrafast Laser-Ablated Bioinspired Hydrogel-Based Porous Gating System for Sustained Drug Release.

Gating systems have been extensively researched in energy harvesting, lab-on-chip applications, and so forth. However, the controlled drug delivery system with artificial hydrogel-based porous gating systems (HPGSs) is rarely reported. Herein, a biomimetic HPGS with a pH-responsive hydrogel as the valve and polydimethylsiloxane as the frame is fabricated by in situ femtosecond laser microdrilling and subsequent ultraviolet exposure. The proposed HPGS loaded with doxorubicin hydrochloride (DOX) is stable under physiological conditions, has a low drug leakage rate, and can achieve sustained drug release in a low pH environment. The experimental results show that the drug release is mainly controlled by non-Fickian diffusion, which renders the dynamic speed control of molecular transport possible. Moreover, the HPGS can also be prepared into an antitumor microcapsule. The results of in vitro cell experiments demonstrate that DOX@HPGS can release drugs and achieve terrific therapeutic efficacy in the elimination of HeLa cells in the acidic environments around tumor cells. This functional HPGS is envisioned to be an ideal pH-response carrier for sustained drug release treatment of digestive diseases such as inflammatory bowel disease and gastrointestinal cancer.

Integration of bioinformatics analysis and experimental validation identifies plasma exosomal miR-103b/877-5p/29c-5p as diagnostic biomarkers for early lung adenocarcinoma.

The aim of this study was to identify miRNAs in plasma exosomes as noninvasive biomarkers for the early diagnosis of lung adenocarcinoma (LUAD). First, exosomal miRNA profiling of three patients with early LUAD and three patients with benign lung disease were screened by next-generation sequencing (NGS) method. Sequencing results showed that 154 exosomal miRNAs were differentially expressed in the plasma of LUAD patients, among which 68 miRNAs were up-regulated and 86 miRNAs were down-regulated. GSE137140 is a GEO database containing serum miRNAs sequencing data from 1566 lung cancer patients and 1774 non-cancer patients controls. When comparing the sequencing data, it was found that most miRNAs (37/68) up-regulated in our LUAD group were also significantly up-regulated in GSE137140, suggesting that circulating miRNAs in lung cancer patients may be enriched in plasma exosomes. In GSE137140, the AUC of the combination of hsa-miR-103b, hsa-miR-29c-5p and hsa-miR-877-5p was 0.873, showing great potential as new tumor markers. To our knowledge, these three exosomal miRNAs have not been reported in lung cancer research. Furthermore, bioinformatics tools were used to analyze the target genes of three candidate miRNAs, which were indeed closely related to the occurrence and development of lung cancer. Bioinformatics algorithms deduced a highly conserved sequence in the 3'-UTR of SFRP4, FOXM1 and TMEM98 that could be bound with miR-103b/877-5p/29c-5p. A luciferase assay indicated that miR-103b/877-5p/29c-5p directly targeted the 3'-UTR of SFRP4, FOXM1 and TMEM98, respectively. Finally, three candidate miRNAs were validated by qRT-PCR in 17 early LUAD samples and 17 control plasma samples. Integration of bioinformatics analysis and experimental validation identifies, this study provides novel insights into miRNA-related networks in LUAD. Hsa-miR-103b, hsa-miR-29c-5p, and hsa-miR-877-5p may be used as diagnostic biomarkers for early LUAD.

Recent developments in isolating methods for exosomes.

Exosomes are the smallest extracellular vesicles that can be released by practically all cell types, and range in size from 30 nm to 150 nm. As the major marker of liquid biopsies, exosomes have great potential for disease diagnosis, therapy, and prognosis. However, their inherent heterogeneity, the complexity of biological fluids, and the presence of nanoscale contaminants make the isolation of exosomes a great challenge. Traditional isolation methods of exosomes are cumbersome and challenging with complex and time-consuming operations. In recent years, the emergence of microfluidic chips, nanolithography, electro-deposition, and other technologies has promoted the combination and innovation of the isolation methods. The application of these methods has brought very considerable benefits to the isolation of exosomes such as ultra-fast, portable integration, and low loss. There are significant functional improvements in isolation yield, isolation purity, and clinical applications. In this review, a series of methods for the isolation of exosomes are summarized, with emphasis on the emerging methods, and in-depth comparison and analysis of each method are provided, including their principles, merits, and demerits.

Optimizing and evaluating PCR-based pooled screening during COVID-19 pandemics.

Population screening played a substantial role in safely reopening the economy and avoiding new outbreaks of COVID-19. PCR-based pooled screening makes it possible to test the population with limited resources by pooling multiple individual samples. Our study compared different population-wide screening methods as transmission-mitigating interventions, including pooled PCR, individual PCR, and antigen screening. Incorporating testing-isolation process and individual-level viral load trajectories into an epidemic model, we further studied the impacts of testing-isolation on test sensitivities. Results show that the testing-isolation process could maintain a stable test sensitivity during the outbreak by removing most infected individuals, especially during the epidemic decline. Moreover, we compared the efficiency, accuracy, and cost of different screening methods during the pandemic. Our results show that PCR-based pooled screening is cost-effective in reversing the pandemic at low prevalence. When the prevalence is high, PCR-based pooled screening may not stop the outbreak. In contrast, antigen screening with sufficient frequency could reverse the epidemic, despite the high cost and the large numbers of false positives in the screening process.

Environmentally Adaptive Shape-Morphing Microrobots for Localized Cancer Cell Treatment.

Microrobots have attracted considerable attention due to their extensive applications in microobject manipulation and targeted drug delivery. To realize more complex micro-/nanocargo manipulation (e.g., encapsulation and release) in biological applications, it is highly desirable to endow microrobots with a shape-morphing adaptation to dynamic environments. Here, environmentally adaptive shape-morphing microrobots (SMMRs) have been developed by programmatically encoding different expansion rates in a pH-responsive hydrogel. Due to a combination with magnetic propulsion, a shape-morphing microcrab (SMMC) is able to perform targeted microparticle delivery, including gripping, transporting, and releasing by "opening-closing" of a claw. As a proof-of-concept demonstration, a shape-morphing microfish (SMMF) is designed to encapsulate a drug (doxorubicin (DOX)) by closing its mouth in phosphate-buffered saline (PBS, pH ∼ 7.4) and release the drug by opening its mouth in a slightly acidic solution (pH < 7). Furthermore, localized HeLa cell treatment in an artificial vascular network is realized by "opening-closing" of the SMMF mouth. With the continuous optimization of size, motion control, and imaging technology, these magnetic SMMRs will provide ideal platforms for complex microcargo operations and on-demand drug release.

Expression Status and Prognostic Value of m6A RNA Methylation Regulators in Lung Adenocarcinoma.

N6-methyladenosine (m6A) RNA modification is the most abundant modification method in mRNA, and it plays an important role in the occurrence and development of many cancers. This paper mainly discusses the role of m6A RNA methylation regulators in lung adenocarcinoma (LUAD) to identify novel prognostic biomarkers. The gene expression data of 19 m6A methylation regulators in LUAD patients and its relevant clinical parameters were extracted from The Cancer Genome Atlas (TCGA) database. We selected three significantly differentially expressed m6A regulators in LUAD to construct the risk signature, and evaluated its prognostic prediction efficiency using the receiver operating characteristic (ROC) curve. Kaplan-Meier survival analysis and Cox regression analysis were used to identify the independent prognostic significance of the risk signature. The ROC curve indicated that the area under the curve (AUC) was 0.659, which means that the risk signature had a good prediction efficiency. The results of the Kaplan-Meier survival analysis and Cox regression analysis showed that the risk score can be used as an independent prognostic factor for LUAD. In addition, we explored the differential signaling pathways and cellular processes related to m6A methylation regulators in LUAD.

Assessment of battery utilization and energy consumption in the large-scale development of urban electric vehicles.

Electrifying transportation in the form of the large-scale development of electric vehicles (EVs) plays a pivotal role in reducing urban atmospheric pollution and alleviating fossil fuel dependence. However, the rising scale of EV deployment is exposing problems that were previously hidden in small-scale EV applications, and the lack of large-scale EV operating data deters relevant explorations. Here, we report several issues related to the battery utilization and energy consumption of urban-scale EVs by connecting three unique datasets of real-world operating states of over 3 million Chinese EVs, operational data, and vehicle feature data. Meanwhile, by incorporating climatic data and EV data outside China, we extend our models to several metropolitan areas worldwide. We find that blindly increasing the battery energy of urban EVs could be detrimental to sustainable development. The impact of changes in the energy consumption of EVs would be exacerbated in large-scale EV utilization, especially during seasonal shifts. For instance, even with a constant monthly driving demand, the average energy consumption of Beijing light-duty EVs would change by up to 21% during winter-spring shifts. Our results may also prove useful for research on battery resources, urban power supply, environmental impacts, and policymaking.

A Sample-In-Answer-Out Microfluidic System for the Molecular Diagnostics of 24 HPV Genotypes Using Palm-Sized Cartridge.

This paper proposes an automated microfluidic system for molecular diagnostics that integrates the functions of a traditional polymerase chain reaction (PCR) laboratory into a palm-sized microfluidic cartridge (CARD) made of polystyrene. The CARD integrates 4 independent microfluidic sample lanes, which can independently complete a sample test, and each sample lane integrates the 3 functional areas of the sample preparation area, PCR amplification area, and product analysis area. By using chemical cell lysis, magnetic silica bead-based DNA extraction, combined with multi-PCR-reverse dot hybridization with microarray, 24 HPV genotypes can be typing tested in CARD. With a custom-made automated CARD operating platform, the entire process can be automatically carried out, achieving sample-in-answer-out. The custom-made operation platform is developed based on a liquid handling station-type, which can automatically load off-chip reagents without placing reagents in CARD in advance. The platform can control six CARDs to work simultaneously, detect 24 samples at a time. The results show that the limit of detection of the microfluidic system is 200 copies/test, and the positive detection rate of clinical samples by this system is 100%, which is an effective method for detection of HPV.

Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2.

BACKGROUND: Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. METHOD: In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. RESULT: The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23-1145.69) for ORF1ab and 528.1 (95% CI: 347.7-1248.7) for N, 401.8 (95% CI: 284.8-938.3) for ORF1ab and 336.8 (95% CI: 244.6-792.5) for N, and 194.74 (95% CI: 139.7-430.9) for ORF1ab and 189.1 (95% CI: 130.9-433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. CONCLUSION: In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

Exosomal miRNAs as biomarkers for diagnostic and prognostic in lung cancer.

More and more studies report that exosomes released by various cells can serve as a medium for information exchange between different cells. Through a deep understanding of the physical and chemical properties of exosomes, the researchers revealed a more precise molecular mechanism of its participation in the process of intercellular communication. In particular, microRNA (miRNA) is found inside exosomes, as well as long noncoding RNA (lncRNA). Extensive evidence indicates that exosomal miRNAs participates in the occurrence and development of lung cancer and plays a variety of roles. Therefore, the release of RNA-containing exosomes in many different kinds of body fluids has caused widespread interest among researchers. In this review, we report evidence from human studies involving miRNAs and other ncRNAs in exosomes associated with lung cancer as diagnostic and prognostic markers. Currently, there is a small amount of evidence that exosomal miRNAs can be used as early diagnosis and prognostic markers for lung cancer, and their exact role in lung cancer patients still needs further study.

hsa_circ_0062389 promotes the progression of non-small cell lung cancer by sponging miR-103a-3p to mediate CCNE1 expression.

Recently, increasing evidence showed that circular RNAs (circRNAs) play critical roles in tumor progression. However, the roles of hsa_circ_0062389 in non-small cell lung cancer (NSCLC) development remain unclear. In the present study, hsa_circ_0062389 expression was significantly increased in NSCLC tissues and cell lines. High hsa_circ_0062389 expression was associated with advanced TNM stage and lymph-node metastasis. Function assays showed that hsa_circ_0062389 suppression reduced NSCLC cells proliferation and arrested cell cycle in G0/G1 phase. In mechanism, hsa_circ_0062389 directly interacted with miR-103a-3p in NSCLC, and CCNE1 acted as a target of miR-103a-3p. Furthermore, rescue assays showed that miR-103a-3p suppression or CCNE1 overexpression abolished the effects of hsa_circ_0062389 suppression on lung cancer cells progression. Therefore, our results showed that the hsa_circ_0062389/miR-103a-3p/CCNE1 axis might contribute to the tumorigenesis of NSCLC, which provided a new strategy for cancer treatment.

Chinese Expert Consensus on the Nucleic Acid Detection of SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) has already become a pandemic wherein the infection's timely diagnosis has proven beneficial to patient treatment and disease control. Nucleic acid detection has been the primary laboratory diagnostic method for the detection of SARS-CoV-2. To ensure laboratory staff safety and quality nucleic acid testing, the Chinese Society of Laboratory Medicine formulated this consensus, based on the Chinese National Recommendations and previous literature for nucleic acid detection. A working group comprises 34 hospital professionals experience with real-time polymerase chain reactions (PCR) testing for SARS-CoV-2 drafted guidance statements during online discussions. A modified Delphi methodology was used in forming a consensus among a wider group of hospital professionals with SARS-CoV-2 detection experience. Guidance statements were developed for four categories: (I) specimen type, priority, collecting, transportation and receiving; (II) nucleic acid isolation and amplification; (III) quality control; (IV) biosafety management and decontamination. The modified Delphi voting process included a total of 29 guidance statements and final agreement. Consensus was reached after two rounds of voting. Recommendations were established for the detection of SARS-CoV-2 using real time PCR testing based on evidence and group consensus. The manuscript was evaluated against The Appraisal of Guidelines for Research & Evaluation Instrument (AGREE II) and was developed to aid medical laboratory staff in the detection of the ribonucleic acid (RNA) of SARS-CoV-2.