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In this study, a ricin toxin (RT)-induced pulmonary intoxication model was established in mice by intratracheal-delivered RT at a dose of 2× LD50. Based on this model, the histopathological evaluation of the lungs at 24 h and 48 h post-exposure was executed, and the genome-wide transcriptome of the lungs at 4, 12, 24 and 48 h post-exposure was analyzed. Histopathological analysis showed that a large number of neutrophils infiltrated the lungs at 24 h post-exposure, and slight pulmonary edema and perivascular-peribronchiolar edema appeared in the lungs at 48 h. Transcriptome analysis showed that the expression of a large number of genes related to leukocyte migration and chemotaxis consistently increased in the lungs upon exposure to RT, and the expression of genes that participate in acute phase immune and/or inflammatory response, also increased within 12 h of exposure to RT, which could be confirmed by the measurement of cytokines, such as IL-1β, TNF-α and IL-6, in bronchoalveolar lavage fluid. While the expression of genes related to cellular components of the extracellular matrix and cell membrane integrity consistently decreased in the lungs, and the expression of genes related to antioxidant activity also decreased within the first 12 h. There are 17 differentially expressed genes (DEGs) that participate in ribotoxic stress response, endoplasmic reticulum stress response or immune response in the lungs at 4 h post-exposure. The expression of these DEGs was upregulated, and the number of these DEGs accounted for about 59 % of all DEGs at 4 h. The 17 DEGs may play an important role in the occurrence and development of inflammation. Notably, Atf3, Egr1, Gdf15 and Osm, which are poorly studied, may be important targets for the subsequent research of RT-induced pulmonary intoxication. This study provides new information and insights for RT-induced pulmonary intoxication, and it can provide a reference for the subsequent study of the toxicological mechanism and therapeutic approaches for RT-induced pulmonary intoxication.

There is no explicit definition for critical ice shapes, and it is only mentioned in some ACs. Here, a rational and applicable definition for critical ice shapes is given based on well understanding of present literatures. Then, the available icing certification guidance concerning the various “critical ice shapes” is outlined. Different methods for determination of ice shapes as well as procedures are presented, and their characteristics are compared and analyzed. Based on the Combination Airfoil Assumption first presented by Glahn et al and developed by Farooq Saeed, we suggest a simple and useful method to determine the critical ice shapes on a normal airfoil which can be called combination airfoil comparison method. This method can be used to quickly get a preliminary ice shape for icing certification, but its criticality should be verified by other means of determining critical ice shapes. In order to examine the availability of this method, examples of Airbus aircraft types that have passed icing certification will be given. We hope that our findings and recommendations will be helpful to the applicant and icing certification team during aircraft icing certification.

For advanced airplane, the Safety of Flight tends to be dependent on complex flight control system. The result is a greatly increased emphasis on flight control system failure effects. FAR25 airworthiness standards are based on, and incorporate, the techniques of the fail-safe design concept. Critical FAR25 airworthiness clauses and Special Conditions about flight control system failures are analyzed. Airworthiness requirements and methods of compliance are studied. Key works in flight control system development are summarized. System safety assessments and failure state verification test are conducted for showing the compliance with airworthiness requirements.

In order to meet the airworthiness requirements (FAR33.70) of large commercial aero-engines, a new approach of probabilistic risk assessment linked durability is presented, and aiming at the issue of low-failure probabilities of key aero-engine structures, probabilistic risk assessment based on the Monte Carlo Radius-Outside Sampling (MCROS) in combination with the Kriging is used, then random factors such as the material, loading and environment can be considered in the given method. Example of probabilistic risk assessment based on fatigue for lower pressure compressor disk of aero-engine demonstrates the applicability, versatility and accuracy of the approach.