Lumbar and neck injuries of occupants in different reclining postures.

PURPOSE: With the increasing level of automation in automobiles, the advent of autonomous vehicles has reduced the tendency of drivers and passengers to focus on the task of driving. The increasing automation in automobiles reduced the drivers' and passengers' focus on driving, which allowed occupants to choose a more relaxed and comfortable sitting position. Meanwhile, the occupant's sitting position went from a frontal, upright position to a more relaxed and reclined one, which resulted in the existing restraint systems cannot to keep occupants safe and secure. This study aimed to determine the effects of different reclining states on occupants' lumbar and neck injuries. METHODS: This is an original research on the field of automotive safety engineering. Occupants in different initial sitting positions (25°, 35°, 45°, and 55°) were adapted to changes in seat back angle and restraint systems and placed in the same frontal impact environment. Neck injury indexes, lumbar axial compression force and acceleration, as well as occupant dynamic response during the impact, were compared in different sitting positions. The injury response and kinematic characteristics of occupants in different reclining positions were analyzed by the control variable method. RESULTS: As the sitting angle increased, the occupant's head acceleration decreased, and the forward-lean angle decreased. Occupants in the standard sitting position had the greatest neck injury, with an Nij of 0.95, and were susceptible to abbreviated injury scale 2+ cervical medullary injuries. As the seatback angle increased, the geometric position of the lumbar spine tended to be horizontal, and the impact load transmitted greater forces to the lumbar spine. The occupant's lumbar injury was greatest in the lying position, with a peak axial compression force on the lumbar region of 5.5 KN, which was 2.3 KN greater than in the standard sitting position. CONCLUSION: The study of occupant lumbar and neck injuries based on different recline states can provide a theoretical basis for optimizing lumbar evaluation indexes, which is conducive to the understanding of the lumbar injury mechanism and the comprehensive consideration of occupant safety protection.

Lactobacillus rhamnosus JYLR-005 Prevents Thiram-Induced Tibial Dyschondroplasia by Enhancing Bone-Related Growth Performance in Chickens.

Tibial dyschondroplasia (TD) is a leg disorder caused by the abnormal development of the tibia in fast-growing poultry. Lactobacillus rhamnosus (L. rhamnosus) strains have been reported to have effects on increasing bone growth and improving osteoporosis in animals. However, whether L. rhamnosus JYLR-005 can improve bone growth in TD chickens remains unclear. In this study, we noted that L. rhamnosus JYLR-005 could not reduce the suppression of the production performance of TD broilers (p > 0.05) but had a slight protective effect on the broiler survival rate (χ2 = 5.571, p = 0.062). However, for thiram-induced TD broiler chickens, L. rhamnosus JYLR-005 could promote tibia growth by increasing tibia-related parameters, including the tibia weight (day 11, p = 0.040), tibia length (day 15, p = 0.013), and tibia mean diameter (day 15, p = 0.035). Moreover, L. rhamnosus JYLR-005 supplementation improved the normal growth and development of the tibial growth plate by maintaining the morphological structure of the chondrocytes and restored the balance of calcium and phosphorus. Taken together, these findings provide a proof of principle that L. rhamnosus JYLR-005 may represent a therapeutic strategy to treat leg disease in chickens.