Abstract Crashworthiness is one of the main concerns in civil aviation safety particularly with regard to the increasing ratio of carbon fiber reinforced plastic (CFRP) in aircraft primary structures. In order to generate dates for model validations, the mechanical properties of T700/3234 were obtained by material performance tests, and energy-absorbing results were gained by quasi-static crushing tests of composite sinusoidal specimens. The correctness of composite material model and single-layer finite element model of composite sinusoidal specimens were verified based on the simulation results and test results that were in good agreement. A typical civil aircraft fuselage section with composite sinusoidal specimens under cargo floor was suggested. The crashworthiness of finite element model of fuselage section was assessed by simulating the vertical drop test subjected to 7 m/s impact velocity, and the influences of different thickness of sub-floor composite sinusoidal specimens on crashworthiness of fuselage section were also analyzed. The simulation results show that the established finite element model can accurately simulate the crushing process of composite sinusoidal specimens; the failure process of fuselage section is more stable, and the safety of occupants can be effectively improved because of the smaller peak accelerations that was limited to human tolerance, a critical thickness of sub-floor composite sinusoidal specimens can restrict the magnitude of acceleration peaks, which has certain reference values for enhancing crashworthiness capabilities of fuselage section and improving the survivability of passengers.

ABSTRACT Objectives: In recent years, DNA ploidy analysis is regarded as having important values in diagnosis and prognostic judgment of malignant tumour. The aim of this study was to explore the clinical significance of DNA ploidy analysis in patients with rectal carcinoma and its precancerous lesions. Subjects and method: Flow cytometry was used to measure the DNA content and ploidy status in normal, precancerous and cancerous fresh rectal tissues. These rectal tissues came from 325 individuals including 120 patients with rectal carcinoma, 25 with proliferative polyps, 155 with villous adenoma and 25 normal controls. The occurrence of DNA heteroploidy was analysed. Results: The positive rate of heteroploidy in patients with rectal carcinoma was significantly higher than that in individuals with proliferative polyps, villous adenoma and normal controls. The positive rate of heteroploidy in patients with villous adenoma with severe atypical proliferation was much higher than that in proliferative polyps, normal controls, and villous adenoma without atypical proliferation, villous adenoma with mild-or-moderated atypical proliferation. The occurrence of DNA heteroploidy was significantly increased with poorer degree of differentiation in rectal carcinoma. Conclusion: The detection of DNA ploidy could be a valuable tool to evaluate the proliferation status and malignant degree of rectal carcinoma. The analysis of DNA ploidy may play an important role in the diagnosis, differential diagnosis, assessment of disease progression and prognosis of rectal carcinoma.

RESUMEN Objetivos: En los últimos años, se considera que el análisis de ploidía del ADN tiene valores importantes en el diagnóstico y pronóstico de los tumoures malignos. El objetivo de este estudio fue explorar la significación clínica del análisis de ploidía del ADN en pacientes con carcinoma rectal y sus lesiones precancerosas. Sujetos y método: La citometría de flujo se utiliza para medir el estado del contenido y ploidía de ADN en tejidos rectales frescos normales, precancerosos y cancerosos. Estos tejidos rectales provenían de 325 individuos incluyendo 120 pacientes con carcinoma rectal, 25 con pólipos proliferativos, 155 con adenoma velloso, y 25 controles normales. Se analizó la presencia de heteroploidía del ADN. Resultados: La tasa positiva de heteroploidía fue significativamente mayor en pacientes con carcinoma rectal que en los individuos con pólipos proliferativos, adenoma velloso y los controles normales. La tasa positiva de heteroploidía fue mucho mayor en pacientes con adenoma velloso con severa proliferación anormal que en los pacientes con pólipos proliferativos, adenoma velloso sin proli-feración anormal, adenoma velloso con proliferación anormal leve o moderado, y los controles normales. La aparición heteroploidía se incrementó significativamente con un grado más pobre de diferenciación en el carcinoma rectal. Conclusión: La detección de la ploidía del ADN podría ser una herramienta valiosa para evaluar el estado de proliferación y el grado de malignidad del carcinoma rectal. El análisis de la ploidía del ADN puede desempeñar un papel importante en el diagnóstico, el diagnóstico diferencial, la evaluación de la progresión de la enfermedad, y el pronóstico de carcinoma rectal.

The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.