Oxidative environment causes molecular remodeling in embryonic heart—a metabolomic and lipidomic fingerprinting analysis

Environmental Science and Pollution Research - Environmental factors including pollution affect human health, and the unifying factor in determining toxicity and pathogenesis for a wide array of...     

Morphological and behavioral alterations induced by endocrine disrupters in amphibian tadpoles

Developmental toxicity effects of endocrine disrupter chemicals, acephate and cypermethrin were studied in Bufo melanostictus tadpoles. Thirty developing eggs of B. melanostictus were exposed to each concentration (0.01, 0.05, 0.1, 0.5, and 1?µg?L^?1) of acephate or cypermethrin in the laboratory (temperature: 23?±?1°C; photoperiod: 11.5–12.5?h). Eggs maintained in conditioned water alone served as controls. After hatching, larvae were fed on boiled spinach until the completion of metamorphosis. In control group, larvae that hatched on 3rd day were heavily pigmented, voracious feeders, and active swimmers; in these tadpoles, hind limb and forelimb-buds emerged on 16th and 24th day and metamorphosis was complete on 32nd day. Eggs exposed to acephate also hatched on 3rd day but larvae exhibited deformities such as, (i) tail distortions, (ii) laterally crooked trunk, (iii) decreased pigmentation, (iv) inactivity, (v) peeling of the skin, and (vi) delay in emergence of limbs and completion of metamorphosis. Cypermethrin-exposed eggs exhibited a delay (4–8 days) in hatching, there was no mortality, deformities in tail, trunk and head region, delay in the emergence of limbs, and completion of metamorphosis were evident. The demonstrated data indicate that these pesticides interfere with amphibian development when present in the aquatic system.     

Effects of initial seated position in low speed rear-end impacts: a comparison with the TNO rear impact dummy (TRID) model

Injury-producing mechanisms associated with rear-end impact collision has remained a mystery not withstanding numerous investigations devoted to its scrutiny. Several criteria have been proposed to predict the injury-causing mechanism, but none have been universally accepted. The challenge lies in determining a set of testing procedures representative of real-world collisions, wherein the results obtained are not only the same as human testing, but remain consistent with various subjects and impact conditions. It is hypothesized that one of the most important considerations in the testing methodology is the effect of initial seated position (ISP) on occupant kinematics during a rear impact collision. This study involves two parts that evaluates the effects of ISP during rear-end impact. In the first part, head acceleration results of computer simulation using Hybrid III TNO rear impact dummy (TRID) are compared to physical impact testing (PIT) of humans. The second part focuses on the computer simulation using TRID to obtain different neck parameters such as NIC (Neck Injury Criterion), NIJ (Neck Injury Predictor), neck forces and moments to predict the level of neck injury such as whiplash associated disorder (WAD) during low speed rear-end impact. In PIT, a total of 17 rear-impact tests were conducted with a nominal 8-km/hour change in velocity to 5 subjects in four different seated positions comprising of a normal position (NP) and three out of positions (OOP). The first position was a NP, defined as torso against the seat back, looking straight ahead, hands on the steering wheel, and feet on the floor. The second position was a head flex position (HFP), defined as the normal position with head flexed forward approximately 20 degrees. The third position was a torso lean position (TLP), defined as the normal position with torso leaned forward approximately 10 degrees away from the seat back. Lastly, a torso lean head flex position (TLHFP), defined as the normal position with the head flexed forward approximately 20 degrees and torso leaned forward approximately 10 degrees. The head acceleration plots from PIT reveal that for the third and fourth positions (TLP and TLHFP) when the subject torso leaned forward, the peak head acceleration for the subject decreased and there was also a delay in reaching the peak. The Hybrid III-TRID anthropomorphic test dummy (ATD) was used in the same four different seated positions using computer simulation software MAthematical DYnamic MOdel (MADYMO 6.0) and the head acceleration results were compared to PIT. The comparison demonstrates that the Hybrid III-TRID ATD with MADYMO can be a reliable testing procedure during low-speed, rear-end impact for the four ISPs considered since the head acceleration plots deviated within the range of PIT head acceleration plots for different human subjects. This ensures that the second part of the study with neck injury using computer simulation results is a reliable testing procedure. It can be observed that MADYMO results have a greater error when compared to PIT when more than one OOP condition is employed as in TLHFP. All these observations would help in providing a tool to better understand the injury mechanisms and provide an accurate testing procedure for rear-end impact.