ABSTRACT
Cold-chain environment could extend the survival duration of SARS-CoV-2 and increases the risk of transmission. However, the effect of clod-chain environmental factors and packaging materials on SARS-CoV-2 stability and the efficacy of intervention measures to inactivate SARS-CoV-2 under cold-chain environment remains uncertain. This study aimed to unravel cold-chain environmental factors that preserved the stability of SARS-CoV-2 and disinfection measures against SARS-CoV-2 under the cold-chain environment. The spike gene of SARS-CoV-2 isolated from Wuhan hu-1 was used to construct the SARS-CoV-2 pseudovirus and used as model of the SARS-CoV-2 virus. The decay rate of SARS-CoV-2 pseudovirus in the cold-chain environment, various types of packaging material surfaces i.e., PE plastic, stainless steel, Teflon and cardboard, and in frozen seawater was investigated. The influence of LED visible light(wavelength 450 nm-780 nm) and airflow movement on the stability of SARS-CoV-2 pseudovirus at -18{degrees} C were subsequently assessed. The results show that SARS-CoV-2 pseudovirus decayed more rapidly on porous cardboard surface compared with the non-porous surfaces including PE plastic, stainless steel and Teflon. Compared with 25{degrees} C, the decay rate of SARS-CoV-2 pseudovirus was significantly lower at low temperature. Seawater preserved viral stability both at -18{degrees} C and repeated freeze-thawing cycles compared with deionized water. LED visible light illumination and airflow movement environment at -18{degrees} C reduced the SARS-CoV-2 pseudovirus stability. In conclusion, our results indicate cold-chain temperature and seawater as risk factors for SARS-CoV-2 transmission and LED visible light illumination and airflow movement as possible disinfection measures of SARS-CoV-2 under the cold-chain environment. ImportanceIt is widely recognized that low temperature is a condition for maintaining virus vitality, and cold-chain transportation spreads the events of the SARS-CoV-2 were reported. This study provides that the decay rate of the SARS-CoV-2 pseudovirus at low temperatures varies on different packaging materials, and salt ions present in frozen foods such as seafood may protect virus survival. These results provide evidence for the possibility of SARS-CoV-2 transmission through cold-chain transport and also suggest the importance for disinfection of items. However, the commonly used disinfection methods of ultraviolet radiation and chemical reagents are generally not suitable for the disinfection of frozen food. Our study shows LED visible light illumination and airflow movement as possible disinfection measures of SARS-CoV-2 under the cold-chain environment. This has implications for reducing the long-distance transmission of the virus through cold-chain transportation.
ABSTRACT
Objective:To investigate the characteristics of magnetic resonance imaging and clinical application of multi-modality magnetic resonance imaging (MRI) for evaluating the response of neoadjuvant chemotherapy (NACT) in inflammatory breast cancer (IBC).Methods:A total of 36 IBC patients were enrolled in the study.The morphological, hemodynamic and diffusion-weighted imaging features of MRI were analyzed. Eleven patients underwent MRI examination before and after NAT. The imaging changes were analyzed and the efficacy of NACT was evaluated.Results:There were 38 identified breast carcinoma in these 36 cases, among which abnormal skin thickening and enhancement, extensive edema was found in 37 breast lesions. Enhancement of breast lesions in 25 cases was non-mass-like enhancement. Diffusion limitation was found in all lesions. The number of vessels in affected side was more than that in healthy side in MIP images. Thirty three cases had axillary lymph node enlargement.The sensitivity and specificity of MRI in evaluating residual breast tumors and vascular thrombus were high, but the evaluation of axillary lymph nodes was relatively low.Conclusions:Multi-modal MRI can be used for early and accurate diagnosis of IBC. It can also be used to predict and evaluate the effect of neoadjuvant chemotherapy.
