Torsional stress is observed in the lower extremity during walking. The feet tend to rotate even though they are in contact with the ground, causing friction. Lower extremity kinematics in the sagittal plane during walking is an important clinical outcome, and few reports exist on the torsional stress of the lower limbs during walking. This study aimed to clarify the relationship between lower extremity kinematics (hip extension, knee extension, and ankle dorsiflexion), which peak in the sagittal plane during the late stance phase of walking, and free moment (FM), serving as an index of torsional stress of the lower extremity. This study included 21 healthy male participants. The peak extension angles of the hip and knee, peak dorsiflexion angle,and FM during the stance phase were measured using a motion capture system. The correlation coefficient between each variable, including walking speed, peak FM (PFM), and impulse of absolute FM (FMimp) were calculated. To clarify the coefficient of determination, a regression analysis was performed on joint kinematics that correlated with FM. In addition, the partial correlation coefficient between the kinematics and FM, excluding the influence of walking speed, was also examined. A regression analysis was performed on joint kinematics that were correlated with FM to determine the determination coefficient. Walking speed and peak dorsiflexion angle showed a positive correlation with PFM (r=0.49, and 0.44, respectively). However, the determination coefficients were low (R2=0.24, and 0.19, respectively). A significant partial correlation coefficient with PFM was found only for the peak hip extension angle (r=0.52). No joints were correlated with FMimp. Regardless of walking speed, there was a positive correlation between FM and sagittal lower limb kinematics. However, since the correlation coefficient was small, it was necessary to consider individual factors such as bone morphology, joint laxity, and walking strategies.
Chicken eggshell membrane (ESM) is a two-layered insoluble sheet located between the eggshell and the albumen and is composed of fibrous proteins. Naturally occurring composite material, such as ESM have various ameliorative effects for osteoarthritis of the knee, joint, and connective tissue when ingested and absorbed as supplements. The physiological effects by oral ESM intake, especially on respiratory function,remain unclear. We have recently reported that tritium-labeled ESM powder can be digested and absorbed by mice and distributed in tissues throughout the body. We have also reported that the application of hydrolyzed water-soluble ESM to human skin significantly improved skin elasticity, which declines with aging, in a before and after comparison at 3 months, and significantly reduced wrinkles at the corners of the eyes compared to controls. In the present double-blind, placebo-controlled study, we examined breathing, skin, and body functions, such as zigzag walking, after ESM ingestion compared to controls. We hypothesized this to improve physical functions by improving the extracellular matrix (ECM) within the range of homeostasis. Among 20 healthy subjects (age: 21–68 years), the group given ESM supplementation for 8 weeks showed significantly increased rate of change in arm skin elasticity, respiratory function (forced expiratory volume in 1 s to forced vital capacity ratio (FEV1/FVC)), and zigzag walking speed compared to controls. There was a significant correlation between the rate of change in FEV1/FVC and that of zigzag walking after 8 weeks compared to the initial values. These functional improvements observed in skin elasticity, lung function, and motor function with oral intake of ESM suggest that maintaining elasticity in the cellular environment can support overall health and activity levels.
A firefighting hose having both an elastomeric lining of circular fabric inside and an elastomeric covering of circular fabric outside is known as the lay flat hose or the through-the-weave hose.
Among the through-the-weave hoses, those having a diameter of over 100 mm are called as largediameter hoses (LDHs). They have been utilized in a wide range of industrial applications such as water supply for hydrofracking, dewatering in mining, transportation of several liquids in logistics, emergency cooling water supply for electrical plants, and dewatering operations by the authorities during floods, in addition to the firefighting application.
On the other hand, we have researched a method to protect LDHs from radiant heat arising from tank fires at petrochemical plants. Radiant heat is one of the major obstacles to firefighting and can cause serious accidents involving both firefighters and their equipment. Thus, LDHs with radiant heat resistance will contribute to successful firefighting operations in the tank fires.
This study evaluates the heat flux resistance of LDH specimens that were subjected to a heat flux exposure experiment conducted in accordance with ISO 6942. After 10kW/m2 of heat flux exposure, the unprotected LDH specimen underwent significant collapse, and the surface temperature of the hose reached 249̊C, which exceeds the flow beginning temperature of the elastomeric materials of which the LHDs are composed. The LDHs specimen protected with an aluminum-deposited aramid fabric cover suffered no damage after 10kW/m2 and 20kW/m2 exposure. The estimation of the radiant heat showed that the aluminum-deposited aramid fabric could protect LDHs from the radiant heat of various flammable liquids at tank fires. These results suggest that the aluminum-deposited aramid fabric is a suitable material for use as an antiradiant heat cover for LDHs.