Pathological changes in the lungs and lymphatic organs of 12 COVID-19 autopsy cases.

Systematic autopsy and comprehensive pathological analyses of COVID-19 decedents should provide insights into the disease characteristics and facilitate the development of novel therapeutics. In this study, we report the autopsy findings from the lungs and lymphatic organs of 12 COVID-19 decedents-findings that evaluated histopathological changes, immune cell signature and inflammatory factor expression in the lungs, spleen and lymph nodes. Here we show that the major pulmonary alterations included diffuse alveolar damage, interstitial fibrosis and exudative inflammation featured with extensive serous and fibrin exudates, macrophage infiltration and abundant production of inflammatory factors (IL-6, IP-10, TNFα and IL-1ß). The spleen and hilar lymph nodes contained lesions with tissue structure disruption and immune cell dysregulation, including lymphopenia and macrophage accumulation. These findings provide pathological evidence that links injuries of the lungs and lymphatic organs with the fatal systematic respiratory and immune malfunction in critically ill COVID-19 patients.

Preliminary Studies on the Absorbance Ratio Method Used to Determining the Age of Stamp-pad Ink Seal.

Stamp-pad ink seals are often placed on important documents, and determining the dating of stamp-pad ink seal is important to assess the authenticity of a document. In this study, 20 different brands and types of stamp-pad inks were classified by ultraviolet visible spectrophotometer. Six different brands and types of papers were classified by micro-Fourier transform infrared spectrometer and visual spectral comparator 6000. Three different brands of stamp-pad inks and two different types of paper were used to make diachronic samples of the seals. A method was employed to date the stamp-pad seals by comparing absorbance ratios and inks of known age. Curves were created to show the relationship between the absorbance ratio of ink and the age of the seals. The experimental results showed that the absorbance ratio method was applicable for the relative dating of stamp-pad ink seals in some cases where the seal was placed on the document within 10 weeks.