Comparative structural analysis of neuromuscular junctions in mice at different ages

The authors studied the histochemical and ultrastructural modifications that occur in the neuromuscular junctions (NMJ) of fibularis longus muscles of mice with an age range of 3 to 21 months. Twenty-four male and female animals were killed at 3, 5, 14 and 21 months of age: 7 of them at 3 months, 4 of them at 5 month, 9 at 14 months and 4 at 21 months. The fibularis longus muscles were processed and their NMJ examined with the transmission electron microscope. The most relevant changes were associated with the degeneration and retraction of terminal axons, i.e., axons poor in synaptic vesicles with degenerated mitochondria, and exhibiting multivesicular bodies and vacuoles; exposed and widened junctional folds and cytoplasmic processes of Schwann cells located in the synaptic gutter. The presence of lysosomes or lipofuchsin in the juxtajunctional sarcoplasm was also noted. These observations suggest that the phenomena of retraction and budding occur in the NMJ with advancing age, with a predominance of events associated with degeneration, leading to profound changes in NMJ shape.

Optimization of neutral hydrolysis reaction of post-consumer PET for chemical recycling

The neutral hydrolysis reaction of post-consumer poly(ethylene terephthalate) in solid state was studied through the reaction of the polymer with water at the molar ratio 1:91 with autogenous pressure. Two sizes of post-consumer PET flakes and temperatures of 135 °C, 170°C and 205°C with pressures of 4.0 atm, 7.5 atm and 13.5 atm, respectively, were considered. With reaction time equal to 6h, the method reached 99% depolymerization at 205°C, 8.2% at 170 °C and 1.7% at 135°C. The reaction extension was measured by separating the terephthalic acid formed in the process and calculating by gravimetry how much material could still be reacted. Through the viscosimetry of diluted, solutions and the counting of carboxylic end groups in the remaining material from the gravimetric assay, it was possible to suggest that the reaction occurs randomly and in the whole volume of the polymeric particle and not solely on the surface. The terephthalic acid obtained and then purified was characterized by elemental analysis, magnetic nuclear resonance, size and panicle size distribution and spectrophotometry in the visible spectrum, and it was similar to the petrochemical equivalent, with purity recorded in carbon base equal to 99.9%.

Recycling of silicon carbide and corn starch as binder originating from commercial starch consolidation

The main goal of this work is to demonstrate that the use of recycled material originated from SiC ceramics is viable. These ceramics were produced by commercial starch consolidation process. Before calcination stage, surplus of these materials always appears. This surplus is rich in SiC and starch. Samples were made by material previously milled in automatic mortar and sieved (100 Tyler). Later, 10% of distilled water was added to the material and the mixture was pressed at 40 MPa. In order to characterize the ceramic, three point flexural test were made, according to the ASTM C1161/94 norm. The results were analyzed by Weibull statistical method. Apparent density and porosity measures also were made, according to ASTM C20/87 norm. A verification of the surface was made in the fracture area by the depth from focus method and SEM image analysis. The results showed that the recycling process is fully viable, being a good economic option and reduce possible pollutant effect to the environment.

Zinc and lead content and availability in Brazilian soil contaminated with residue of a secondary smelting lead recycling plant

The sequential extraction procedure of Zinc and lead performed in a Brazilian soil showed that it presents high pollution potential once over 90% of total lead is present in fractions where the metals can be easily mobilized. The fraction contents are as follow: F1 = 174 and 15 mg kg-1; F2 = 3155 and 9.7 mg kg -1; F3 = 99 and 1.6 mg kg -1; Residual fraction = 38 and 5.5 mg kg -1 for lead and zinc, respectively. The comparison with non contaminated soil only Pb 2+ concentration is above its intervention reference concentration, 900 mg kg -1.

Motor Recovery and Synaptic Preservation after Ventral Root Avulsion and Repair with a Fibrin Sealant Derived from Snake Venom

Background:Ventral root avulsion is an experimental model of proximal axonal injury at the central/peripheral nervous system interface that results in paralysis and poor clinical outcome after restorative surgery. Root reimplantation may decrease neuronal degeneration in such cases. We describe the use of a snake venom-derived fibrin sealant during surgical reconnection of avulsed roots at the spinal cord surface. The present work investigates the effects of this fibrin sealant on functional recovery, neuronal survival, synaptic plasticity, and glial reaction in the spinal motoneuron microenvironment after ventral root reimplantation.Methodology/Principal Findings:Female Lewis rats (7 weeks old) were subjected to VRA and root replantation. The animals were divided into two groups: 1) avulsion only and 2) replanted roots with fibrin sealant derived from snake venom. Post-surgical motor performance was evaluated using the CatWalk system twice a week for 12 weeks. The rats were sacrificed 12 weeks after surgery, and their lumbar intumescences were processed for motoneuron counting and immunohistochemistry (GFAP, Iba-1 and synaptophysin antisera). Array based qRT-PCR was used to evaluate gene regulation of several neurotrophic factors and receptors as well as inflammatory related molecules. The results indicated that the root reimplantation with fibrin sealant enhanced motor recovery, preserved the synaptic covering of the motoneurons and improved neuronal survival. The replanted group did not show significant changes in microglial response compared to VRA-only. However, the astroglial reaction was significantly reduced in this group.Conclusions/Significance:In conclusion, the present data suggest that the repair of avulsed roots with snake venom fibrin glue at the exact point of detachment results in neuroprotection and preservation of the synaptic network at the microenvironment of the lesioned motoneurons. Also such procedure reduced the astroglial reaction and increased mRNA levels to neurotrophins and anti-inflammatory cytokines that may in turn, contribute to improving recovery of motor function. © 2013 Barbizan et al.

Efeitos da bupropiona sobre o comportamento sexual, parâmetros espermáticos e fertilidade de ratos machos e sobre a contratilidade do ducto epididimático in vitro

Pós-graduação em Biologia Geral e Aplicada - IBB

An emergy-based evaluation of a reverse logistics network for steel recycling

Efficient implementation of recycling networks requires appropriate logistical structures for managing the reverse flow of materials from users to producers. The steel sheet distributor studied had established a protocol for scrap recovery with the steel plant and its customers. The company invested in producing containers, hiring a specialized labor force and in purchasing trucks for container transportation to implement the logistics network for recycling. That network interconnected the company with two kinds of customers: the ones returning scrap and the ones who preferred to continue business-as-usual. The logistical network was analyzed using emergy synthesis, and the data obtained were used to evaluate and compare the system's environmental costs and benefits from the perspective of the distributor and the steel plant operator. The use of emergy ternary diagrams provided a way to assess recycle strategies to compare the relative economic and environmental benefits of the logistical network implemented. The minimum quantity of scrap that the distributor must recover to improve environmental benefits was determined allowing decision on whether it is worth keeping the system running. The new assessment method proposed also may help policy-makers to create strategies to reward or incentive users of reverse logistics, and help to establish regulations, by decreasing taxes or stimulating innovation, for effectively implement the National Policy on Solid Waste. (C) 2013 Elsevier Ltd. All rights reserved.

Sperm Bundles in the Seminal Vesicle of the Crematogaster victima (Smith) Adult Males (Hymenoptera: Formicidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparison of polymers and ceramics in new and discarded electrical insulators: reuse and recycling possibilities

The expansion and maintenance of electricity distribution networks generates large amounts of waste, much of it in the form of discarded insulators that are not reused or recycled. This paper describes the results of tests on used and new ceramic and polymeric insulators to verify if their exposure to weathering justifies their replacement. In new and used ceramic insulators, properties such as contact angle, relative density, porosimetry, dilatometry and X-ray diffraction patterns showed no differences or the differences that were found could not be related to their use. The discarded ceramic material showed high thermal stability, an interesting characteristic for application as chamotte. It can also be reused to replace gravel used in substations. In polymeric insulators, thermogravimetry, differential scanning calorimetry and relative density test results suggest degradation of used material compared to new. This would justify their replacement and discard as waste, but they show little recycling potential.

Synaptic plasticity and sensory-motor improvennent following fibrin sealant dorsal root reimplantation and mononuclear cell therapy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Immobilization of papain on chitin and chitosan and recycling of soluble enzyme for deflocculation of saccharomyces cerevisiae from bioethanol distilleries

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Natural rubber/leather waste composite foam: A new eco-friendly material and recycling approach

This article describes a new approach of recycling the leather waste (shavings) using it as filler in natural rubber foams composites. The foams were prepared using different amounts of leather waste (0-60 parts per hundred of rubber) and submitted to morphological (SEM microscopy) and mechanical analyses (cyclic stress-strain compression). The increase of leather shavings on the composite causes an increase of viscosity in the mixture, which reflects in the foaming process. This results in smaller and fairly uniform cells. Furthermore, expanded rubber has the biggest cell size, with more than 70% of cell with 1000 mu m, while the composite with the higher concentration of leather has around 80% of total number of cells with 100-400 mu m. The mechanical parameters were found to depend on the leather dust concentration. Moreover, the stiffness rises with the increase of leather shavings; consequently, the compression force for expanded rubber was 0.126 MPa as well as the composite with higher concentration of leather was 7.55 MPa. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41636.