26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)

Thermal Properties of Conducting Polypyrrole Nanotubes

Thermal properties of polypyrrole nanotubes synthesized by the chemical oxidation of pyrrole with iron(III) chloride in the presence of methyl orange as structure-guiding template, have been investigated. As-prepared polypyrrole salt and corresponding base were compressed into pellets. Thermogravimetric analysis has shown that the heating/cooling of both polymers is connected with water desorption/re-absorption. This process influences all temperature dependences of the thermophysical properties. The specific heat of both polypyrrole forms was the same at 35°C. The thermal diffusivity of polypyrrole base was lower than that of the salt. The dilatational characteristics are strongly influenced by water desorption/re-absorption. Water desorption is connected with the contraction of polypyrrole and its re-absorption with the expansion of polypyrrole. The electrical resistivity was measured, in analogy to thermal experiments, by a four-point van der Pauw method. The electrical resistivity was 0.016 and 10.2 Ωcm at room temperature, for both materials. The electrical resistivity was also influenced by water desorption/re-absorption as well as other thermophysical properties

Thermal Properties of Conducting Polypyrrole Nanotubes

Thermal properties of polypyrrole nanotubes synthesized by the chemical oxidation of pyrrole with iron(III) chloride in the presence of methyl orange as structure-guiding template, have been investigated. As-prepared polypyrrole salt and corresponding base were compressed into pellets. Thermogravimetric analysis has shown that the heating/cooling of both polymers is connected with water desorption/re-absorption. This process influences all temperature dependences of the thermophysical properties. The specific heat of both polypyrrole forms was the same at 35°C. The thermal diffusivity of polypyrrole base was lower than that of the salt. The dilatational characteristics are strongly influenced by water desorption/re-absorption. Water desorption is connected with the contraction of polypyrrole and its re-absorption with the expansion of polypyrrole. The electrical resistivity was measured, in analogy to thermal experiments, by a four-point van der Pauw method. The electrical resistivity was 0.016 and 10.2 Ωcm at room temperature, for both materials. The electrical resistivity was also influenced by water desorption/re-absorption as well as other thermophysical properties

BOAR SPERM HEAD MEMBRANE DAMAGE DURING CRYOPRESERVATION EVALUATED BY ELECTRON MICROSCOPY

Abstract As electron microscopy can reveal much smaller changes in plasma membrane integrity than optical methods, it appears to be a useful tool for evaluating semen quality or the damage inflicted on spermatozoa during preservation. By evaluating membrane integrity of the sperm head in 16 boars by transmission electron microscopy (TEM), it was found that the plasma membrane is very sensitive and tends to break in the acrosomal area but not in the rest of the sperm head. The earliest signs of injury to spermatozoa in the acrosomal part of the sperm head were observed in the plasma membrane that became swollen, broken or lost. The next damaged part of spermatozoa which is less sensitive than the plasma membrane is the acrosome and its external membrane. The freezing process caused a substantial increase in the degree of cell damage manifested as disturbed or missing plasma membrane, acrosomal reaction-like changes and unevenly distributed or lost acrosomal contents. The latter was not found in fresh semen. Using an appropriate buffer concentration for the fixatives applied during preparation of semen samples for TEM appeared as a very important factor due to the impact of their osmolality on plasma membrane integrity of sperm cells