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We present the results of a remote experimental evaluative activity using video analysis in the study of geometric optics. The activity adresses contents concerning refraction of light. This was applied to students of undergraduate courses for the formation of teachers of biology, physics, mathematics, and chemistry, as well as for production and meteorological engineering, enrolled in the Introduction to Physical Sciences I course at the Center for Distance Learning Superior Education of the State of Rio de Janeiro (CEDERJ). Part of the assessments carried out by the students were selected, discussed and presented as a result of this work. [ABSTRACT FROM AUTHOR]

The effectiveness of Ilizarov external fixators in osteosynthesis of fractured bones depends on the pre-tension applied to the transosseous wires. The pre-tension on these wires depends on the initial torque applied to the slotted bolts, which occasionally fracture during clinical setup. There is no standard method to determine the risk of failure of these bolts. This study aimed to develop a test to evaluate the mechanical strength of these bolts by imitating a bolt-wire-ring-nut configuration of an Ilizarov fixator. The fracture micromechanisms of the slotted bolts were investigated to understand the mechanical forces involved. This resulted in a reference group (Group III). Then, with these fracture characteristics, a new bolt-wire-ring-nut test was developed to mimic use in an Ilizarov fixator. Eleven slotted bolts were tested (Group II). The new test results were compared with a standardized screw torsion test (Group I) according to ASTM F543, Standard Specification and Test Methods for Metallic Medical Bone Screws. The mechanical strengths of Groups I and II were analyzed statistically. Additionally, the fracture micromechanisms of all groups were investigated. The bolts tested according to ASTM F543 (Group I) showed values with less dispersion compared with those in Group II; however, there were no statistically significant differences between their maximum torques. The bolts submitted to the new test (Group II) showed similar fracture surfaces as those in Group III, distinct from Group I. The results indicate that the new torsion test is more clinically relevant and reliable when checking whether the slotted bolts are liable to fracture during clinical setup. [ABSTRACT FROM AUTHOR]

An abstract of the study "Progesterone, Estrogen (ER-α and ER-β), and Oxytocin Receptor Gene Expression in Canine Embryos," by A. A. P. Derussi et al. is presented.

The aim was to assess hormone receptor gene expression in the oviduct and uterus during canine pregnancy. Nineteen pregnant bitches divided into four groups were ovariohysterectomized (OVH) at either day 8, 12, 21 or 60 of pregnancy, and five non-pregnant females underwent OVH 12 days after the pre-ovulatory Luteinizant Hormone (LH) surge and served as controls. RT-qPCR for progesterone (PR), oestrogen (ER-α and ER-β) and oxytocin (OTR) receptors was performed on the oviduct and uterine tissue. The mRNA PR expression in the uterus during early stages of pregnancy and the luteal phase was higher than at other times. The mRNA ER-β expression in the oviduct during early pregnancy was less than in non-pregnant bitches. In the uterus, the mRNA ER-β expression was higher in the initial stages of pregnancy. The ER-α expression was higher in the oviduct and uterus in advanced stages of pregnancy. The mRNA OTR expression in the oviduct was lower than in the uterus in control group. The expression of this receptor in oviduct and the uterus was higher in the final stages of pregnancy, when compared with other phases. These data suggested that the serum progesterone concentrations probably exert a direct control on the PR and ER (α and β) expression and indirectly on OTR expression in the bitch oviduct and uterus., (© 2012 Blackwell Verlag GmbH.)