Objective: The aim of this study was to investigate the clinical and computed tomography (CT) features associated with severe and critical coronavirus disease 2019 pneumonia. Materials and Methods: Eighty-three patients with COVID-19 pneumonia including 25 severe/critical cases and 58 ordinary cases were enrolled. The chest CT images and clinical data of them were reviewed and compared. The risk factors associated with disease severity were analyzed. Results: Compared with the ordinary patients, the severe/critical patients had older ages, higher incidence of comorbidities, cough, expectoration, chest pain, and dyspnea. The incidences of consolidation, linear opacities, crazy-paving pattern, and bronchial wall thickening in severe/critical patients were significantly higher than those of the ordinary patients. Besides, severe/critical patients showed higher incidences of lymph node enlargement, pericardial effusion, and pleural effusion than the ordinary patients. The CT scores of severe/critical patients were significantly higher than those of the ordinary patients (P < 0.001). Receiver operating characteristic curve showed that the sensitivity and specificity of CT score were 80.0% and 82.8%, respectively, for the discrimination of the 2 types. The clinical factors of age older than 50 years, comorbidities, dyspnea, chest pain, cough, expectoration, decreased lymphocytes, and increased inflammation indicators were risk factors for severe/critical COVID-19 pneumonia. Computed tomography findings of consolidation, linear opacities, crazy-paving pattern, bronchial wall thickening, high CT scores, and extrapulmonary lesions were features of severe/critical COVID-19 pneumonia. Conclusions: There are significant differences in clinical symptoms, laboratory examinations, and CT manifestations between the ordinary patients and the severe/ critical patients. Many factors are related to the severity of the disease, which can help clinicians to judge the severity of the patient and evaluate the prognosis.

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All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Effects of Mulch Cover Rate on Interrill Erosion Processes and the Size Selectivity of Eroded Sediment on Steep Slopes Soil & Water Management & Conservation S oil erosion by water is not only associated with on-site land degradation but also greatly contributes to negative downstream off-site impacts such as flooding, pollution, and siltation of water bodies. Soil erosion by water involves the detachment, transport, and deposition of soil materials due to the erosive forces of raindrops and runoff, and these processes are commonly divided into rill and interrill components depending on the source of eroded sediment (Meyer and Wischmeier, 1969). In regions of the world where rainfall intensities are not high, rates of interrill erosion can be considerable; even where rainfall intensities are high, interrill areas occupy a pivotal position in the erosion system, acting as links between incident rainfall and those areas of concentrated flow (rills and gullies) where most erosion occurs (Issa et al., 2006). Interrill soil erosion processes tend to be size selective, and the particle-size distribution (PSD) of eroded sediment can provide basic information regarding erosion processes (

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An efficient system was established for a higher frequency of protocorm-like body (PLB) formation from the callus of Dendrobium candidum Wall ex Lindl. The calluses were induced from longitudinally bisected segments of protocorms and subcultured two times every 40d on Murashige and Skoog medium with macronutrients at half strength, micronutrients at full strength, 2% sucrose, and with 8.8μM 6-Benzylaminopurine. PLB formation was achieved when calluses were transferred onto the same basal medium without any plant growth regulators. PLBs developed into intact plantlets about 2cm in height and with four roots when on basal medium with 2.7μM 1-naphthaleneacetic acid. Plantlets were transplanted into vermiculite with a 95% survival rate in a greenhouse. Histological observations proved that globular somatic embryos could be produced from the inside and surface of the embryogenic callus during PLB formation.