Correction: Yu et al. Comparison of Physical and Biochemical Characterizations of SARS-CoV-2 Inactivated by Different Treatments. Viruses 2022, 14, 1938.

In the original publication [...].

Repeat-Dose Toxicity of Candidate Omicron COVID-19 Vaccine in Sprague-Dawley Rats

Due to a large number of mutations in the spike protein and immune escape, the Omicron variant (B.1.1.529) has become a predominant variant of concern (VOC) strain. To prevent the disease, we developed a candidate inactivated vaccine (Omicron COVID-19 Vaccine (Vero Cell), Inactivated). To evaluate the safety of the vaccine, we tested the repeat-dose toxicity in Sprague-Dawley (SD) rats. The doses were administered randomly to three groups: physiological saline solution (control), aluminum adjuvant in PBS solution adjuvant (adjuvant group), and low-dose and high-dose omicron vaccines (vaccine group) for 6 weeks. The SD rats were allowed to recover for 4 weeks after withdrawal. We evaluated the physiological condition of the rats, including their ophthalmological condition, body weight, food intake, body temperature, blood biochemistry, urine, neutralizing antibody, inflammation at the injection site, and organs weight. In summary, no dose-dependent adverse toxicological changes were observed, and a recovery trend was obvious, which proved the preclinical safety of the candidate omicron vaccine and provided evidence for clinical trials in humans. [ FROM AUTHOR] Copyright of COVID is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Repeat-Dose Toxicity of Candidate Omicron COVID-19 Vaccine in Sprague-Dawley Rats

Due to a large number of mutations in the spike protein and immune escape, the Omicron variant (B.1.1.529) has become a predominant variant of concern (VOC) strain. To prevent the disease, we developed a candidate inactivated vaccine (Omicron COVID-19 Vaccine (Vero Cell), Inactivated). To evaluate the safety of the vaccine, we tested the repeat-dose toxicity in Sprague-Dawley (SD) rats. The doses were administered randomly to three groups: physiological saline solution (control), aluminum adjuvant in PBS solution adjuvant (adjuvant group), and low-dose and high-dose omicron vaccines (vaccine group) for 6 weeks. The SD rats were allowed to recover for 4 weeks after withdrawal. We evaluated the physiological condition of the rats, including their ophthalmological condition, body weight, food intake, body temperature, blood biochemistry, urine, neutralizing antibody, inflammation at the injection site, and organs weight. In summary, no dose-dependent adverse toxicological changes were observed, and a recovery trend was obvious, which proved the preclinical safety of the candidate omicron vaccine and provided evidence for clinical trials in humans.

Comparison of Physical and Biochemical Characterizations of SARS-CoV-2 Inactivated by Different Treatments.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused huge social and economic distress. Given its rapid spread and the lack of specific treatment options, SARS-CoV-2 needs to be inactivated according to strict biosafety measures during laboratory diagnostics and vaccine development. The inactivation method for SARS-CoV-2 affects research related to the natural virus and its immune activity as an antigen in vaccines. In this study, we used size exclusion chromatography, western blotting, ELISA, an electron microscope, dynamic light scattering, circular dichroism, and surface plasmon resonance to evaluate the effects of four different chemical inactivation methods on the physical and biochemical characterization of SARS-CoV-2. Formaldehyde and ß-propiolactone (BPL) treatment can completely inactivate the virus and have no significant effects on the morphology of the virus. None of the four tested inactivation methods affected the secondary structure of the virus, including the α-helix, antiparallel ß-sheet, parallel ß-sheet, ß-turn, and random coil. However, formaldehyde and long-term BPL treatment (48 h) resulted in decreased viral S protein content and increased viral particle aggregation, respectively. The BPL treatment for 24 h can completely inactivate SARS-CoV-2 with the maximum retention of the morphology, physical properties, and the biochemical properties of the potential antigens of the virus. In summary, we have established a characterization system for the comprehensive evaluation of virus inactivation technology, which has important guiding significance for the development of vaccines against SARS-CoV-2 variants and research on natural SARS-CoV-2.

Meta-Seg: A Survey of Meta-learning for Image Segmentation

A well-performed deep learning model in image segmentation relies on a large number of labeled data. However, it is hard to obtain sufficient high-quality raw data in industrial applications. Meta-learning, one of the most promising research areas, is recognized as a powerful tool for approaching image segmentation. To this end, this paper reviews the state-of-the-art image segmentation methods based on meta-learning. We firstly introduce the background of the image segmentation, including the methods and metrics of image segmentation. Second, we review the timeline of meta-learning and give a more comprehensive definition of meta-learning. The differences between meta-learning and other similar methods are compared comprehensively. Then, we categorize the existing meta-learning methods into model-based, optimization-based, and metric-based. For each categorization, the popular used meta-learning models are discussed in image segmentation. Next, we conduct comprehensive computational experiments to compare these models on two pubic datasets: ISIC-2018 and Covid-19. Finally, the future trends of meta-learning in image segmentation are highlighted.

Eliciting positive emotion through strategic responses to COVID-19 crisis: Evidence from the tourism sector.

While social media are effective means of communicating with adverse customer emotions during a crisis, it remains unclear how tourism organisations can respond to pandemic crisis on social media to prevent negative aftermaths. Using a set-theoretical approach, we investigate how COVID-19 response strategies and linguistic cues of responses are intertwined to evoke positive emotions among consumers. This study entails a qualitative content analysis of tourism organisations' COVID-19 announcements and a social media analytics approach that captures consumers' emotional reactions to these announcements via their Twitter replies. Our results extend some well-established findings in the tourism crisis literature by suggesting that combining innovative response strategy, argument quality, and assertive language can reinforce positive emotions during the COVID-19 crisis. Taking organisational characteristics into consideration, we suggest that young established hotels utilise innovative response strategies, whereas retrenchment response strategies for all types of restaurants should be avoided during the COVID-19 crisis.

Corporate Responses to the Coronavirus Crisis and their Impact on Electronic-Word-of-Mouth and Trust Recovery: Evidence from Social Media

Abstract This study examines how corporate responses to service failure, caused by the coronavirus (COVID-19) crisis, influence electronic-word-of-mouth (E-WoM) and trust recovery around lockdown, using multiple data sources. A dataset of 398 valid COVID-19 announcements from 50 UK food retailers posted on the social media platform Twitter, and 21,960 consumer comments associated with these announcements, are analysed using content analysis and social media analytics, respectively. In Study 1, we test the effects of corporate crisis response strategy (defensive vs. offensive) and response framing (emotional vs. rational) on consumer E-WoM (measured as ?consumer sentiment?). The results reveal that using a defensive corporate response strategy with emotionally framed announcements leads to more positive consumer E-WoM. In Study 2, we advance the findings of Study 1 using a vignette-based experimental design to examine how social media announcements made by food retailing brands influence consumers? trust recovery. We find that consumer trust recovers significantly when corporate COVID-19 responses are framed in an emotional manner. By drawing upon signalling theory, this study makes an important contribution to public health crisis communication and service failure literature by demystifying consumers? reactions towards corporate crisis responses amid a pandemic.