Abstract Tires are a critical component of military wheeled vehicles and are exposed to the threat of fragment caused by explosion of warhead on the battlefield. To study the ballistic impact response of military vehicle tires under fragment, experiments and numerical simulations of spherical fragments impacting tires were carried out. The damage mode of the tires was analyzed. The effects of obliquity, tire thickness, and fragment mass on the dynamic response of tires, as well as the ballistic limit velocity, were analyzed. The results indicate that: (1) The main failure modes of the tire comprise local erosion near the center of the perforation, elastic deformation surrounding the perforation, and tensile fracture of the steel cords. (2) The process of fragment penetration into a tire can be divided into four stages: the entry stage, stable penetration stage, cord layer penetration stage, and fragment exit stage. (3) The cord structure demonstrates its ability to undergo plastic deformation to a certain extent and its restraining effect on the rubber.

Abstract: Video-assisted self-reflection (VASR) has been identified as an effective pedagogical tool in teacher education, and yet it has been rarely researched in the context of teaching EFL students to make oral presentations (OPs). This study aimed at investigating the effectiveness of VASR in teaching EFL students to make OPs and the students’ perceptions of its pedagogical use. A quasi-experimental two-group pre-test post-test comparison design was used. The experimental group (n = 14) and the control group (n = 15) experienced the same instructional procedures for 14 weeks, while only the experimental group made VASRs. Two questionnaires were used as instruments, one completed by both groups first as the pre-test and then as post-test to investigate the effectiveness of VASR, and the other completed by the experimental group to examine students’ perceptions. The results suggested that VASR was effective in developing students’ use of non-verbal elements in communication and that students perceived VASRs as beneficial activities. A structured protocol was recommended to facilitate students’ VASRs and maximize its pedagogical effect. The findings have implications for the design of VASRs in teaching EFL students to make OPs.

Resumen: Se ha identificado a la autorreflexión asistida por video como una herramienta efectiva en la formación de profesores, pero casi nunca ha sido investigada en el contexto de enseñar a esos estudiantes de inglés como lengua extranjera al hacer presentaciones orales. Esta investigación pretende investigar la eficacia de la autorreflexión asistida por video como método de enseñar a estudiantes de inglés como lengua extranjera a hacer presentaciones orales, y las percepciones de estudiantes acerca del uso pedagógico de videos. Hemos empleado un diseño cuasi-experimental de pre-test/post-test, con dos grupos. El grupo experimental (n = 14) y el grupo de control (n = 15) recibieron la misma enseñanza durante 14 semanas, pero solo el grupo experimental hizo autorreflexión asistida por video. Se usan dos cuestionarios como instrumentos, uno rellenado por ambos grupos en la pre-test y de nuevo en la post-test para investigar la eficacia de autorreflexión asistida por video, y el otro completado por el grupo experimental solamente, para examinar las percepciones de esos estudiantes. Los resultados sugirieron que la autorreflexión asistida por video resultó efectiva para desarrollar el uso de elementos no verbales en la comunicación, y que los estudiantes pensaron que la autorreflexión asistida por video fue una actividad beneficiosa para ellos. Se sugirió un protocolo estructurado que puede facilitar la autorreflexión y aumentar sus efectos. Los hallazgos son importantes a la hora de diseñar la autorreflexión asistida por video para enseñar estudiantes de inglés como lengua extranjera cuando se hacen presentaciones orales.

Abstract This study aimed to use gene chips to investigate differential gene expression profiles in the occurrence and development of acute myocardial infarction (AMI). The study included 12 AMI patients and 12 healthy individuals. Total mRNA of peripheral bloodwas extracted and reversed-transcribed to cDNA for microarray analysis. After establishing two pools with three subjects each (3 AMI patients and 3 healthy individuals), the remaining samples were used for RT-qPCR to confirm the microarray data. From the microarray results, seven genes were randomly selected for RT-qPCR. RT-qPCR results were analyzed by the 2-ΔΔCt method. Microarray analysis showed that 228 genes were up- regulated and 271 were down-regulated (p ≤ 0.05, |logFC| > 1). Gene ontology showed that these genes belong to 128 cellular components, 521 biological processes, and 151 molecular functions. KEGG pathway analysis showed that these genes are involved in 107 gene pathways. RT-qPCR results for the seven genes showed expression levels consistent with those obtained by microarray. Thus, microarray data could be used to select the pathogenic genes for AMI. Investigating the abnormal expression of these differentially expressed genes might suggest efficient strategies for the prevention, diagnosis, and treatment of AMI.