bluuebunny/crossref_metadata_2025 huggingface dataset:
Plastic Anisotropy of Ultrafine Grained Al Alloy AA6016 Produced by Accumulative Roll Bonding
Authors: Skrotzki Werner , Scharnweber J. , Oertel C.G. , Höppel Heinz Werner , Topic Irena , Brokmeier Heinz Günter , Jaschinski J.
Published: March 2010

In order to quantify the plastic anisotropy of the ultrafine grained aluminium alloy AA6016 produced by accumulative roll-bonding (ARB) the Lankford parameter is measured by tensile testing as a function of the number of ARB cycles. The experimental results are compared with those from texture-based Taylor simulations. Increasing differences between experiment and theory at higher number of ARB cycles may be attributed to highly oriented microstructural features.
Textures and Microstructures in Peridotites from the Finero Complex (Ivrea Zone, Alps) and their Influence on the Elastic Rock Properties
Authors: Ullemeyer K. , Leiss B. , Stipp M.
Published: March 2010

In order to quantify differences in the elastic rock properties as a result of fabric differences, peridotite samples from the Finero complex were investigated with respect to their mineral textures and elastic properties. Our data indicate only weak to intermediate texture strengths and weak elastic anisotropy, which is too small to produce a significant acoustic contrast in a seismic experiment. Consequently, internal structures from peridotite bodies in the Earth's crust with such fabric characteristics cannot be resolved reliably.
Correlation between the Magnetic Properties and the Crystallographic Texture during the Processing of Non Oriented Electrical Steel
Authors: Verbeken Kim , Gomes Edgar , Schneider Juergen , Houbaert Yvan
Published: March 2010

The magnetic properties in electrical steels are strongly dependent on the crystallographic texture as well as other microstructural features such as grain size. Both, texture and grain size, are determined by the thermo-mechanical history of the material. This work regards a set of different thermo-mechanical paths applied on two types of non-oriented electrical steels containing 2.4% and 3.0%Si, respectively. The evolution of grain size, microstructure morphology and texture throughout processing were studied in detail by optical microscopy, X-Ray diffraction and Electron BackScatter Diffraction (EBSD). The impact of the texture on the magnetic properties was evaluated. This was done by the calculation of the magnetic anisotropy energy and the A parameter, i.e. a parameter defined in scientific literature that describes the magnetic "quality" of the texture, which can be correlated with the magnetic properties of the materials. Finally, the influence of further laser cutting on the crystallographic texture will be examined as well.
Microstructure Investigations of the Phase Boundaries in the Bridgman TRIP Steel Crystal
Authors: Borisova D. , Schimpf C. , Jahn Andreas , Klemm V. , Schreiber G. , Šimek D. , Rafaja David
Published: March 2010

Formation of microstructure defects at the phase boundaries in TRIP steels was investigated with the aid of microstructure analysis on a TRIP steel crystal, which was grown by the Bridgman technique. The microstructure studies comprised scanning electron microscopy (SEM), X-ray diffraction (XRD), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and transmission electron microscopy with high resolution (HRTEM). Initial XRD measurements revealed that the crystals under study consist of austenite and ferrite with extremely strong preferred orientations. Subsequent XRD pole figure measurements and EBSD scans have shown that the orientation relationship between austenite and ferrite can be described by the Nishiyama-Wassermann model. For a detailed description of the microstructure of the Bridgman crystal, the orientation distribution of crystallites within the individual phases was investigated using the XRD reciprocal space mapping and the rocking curve measurements. These experiments have shown that the density of microstructure defects is much lower in ferrite than in austenite. The direct information about the defect structures at the phase boundaries between austenite and ferrite was obtained from the TEM micrographs, which revealed complicated micro-twin structures at the boundaries between the neighbouring phases. HRTEM discovered very narrow stripes of ferrite embedded in austenite that were regarded as a source of the microstructure defects in austenite.
An Easy Approach to Increase the Precision of EBSD Analysis – Examples from a Sea Urchin Calcite Study
Authors: Goetz Andreas , Griesshaber Erika , Schmahl Wolfgang W.
Published: March 2010

Sea urchins mineralize Mg-calcite skeletons, both, within their exoskeletons as well as in their spines. In this study we have investigated sea urchin spines of the species Amblypneustes pachistus. The spines are round and consist of several wedges that extend from the base to the tip of the spine. The wedges are connected to each other by porous calcite. Rocking curves of the spines show a distribution of 0.5° of the 110 reflection, with the domains being misoriented by 0.1° to each other. In our EBSD system the average mean angular (MAD) deviation is 0.3°. This is higher than the signal that is needed for the detection of small misorientations of domains within a sea urcin spine.
In order to increase the precision (not the accuracy) of the EBSD measurements several factors, such as geometric artifacts and charging of calcite were minimized. Handling of these factors and utilizing the subsequently described statistical approach allowed for the identification of different domains within the spines. It further allowed calculating the degree of misorientation between these domains. Our EBSD analyses and the subsequent evaluation of the data show that the wedges forming the spines of Amblypneustes pachistus are mosaic crystals. The misorientation of the wedges to each other increases from the base of the spine towards its tip.
The here proposed method for increasing the precision of the angular resolution showed reproducibility on silicon of 0.05°.
Texture Control in Non-Oriented Electrical Steels by Severe Plastic Deformation
Authors: Kestens Leo , Petrov Roumen H. , Gobernado Patricia , Leunis Elke
Published: March 2010

Although plenty of research has already been carried out on the issue of texture control in non-oriented electrical steels, there is not yet a universally applied industrial process to obtain an optimized {001} fibre texture. Among the various laboratory processes that have been studied so far, cross rolling seems to be one of the most promising approaches. For evident reasons cross-rolling cannot be implemented on a conventional continuous rolling line of an industrial plant. In the present study a potential interesting alternative is presented which may deliver a similar texture evolution as the cross rolling process, but can be applied in a continuous line of hot and cold rolling operations followed by recrystallization annealing. By applying severe rolling reductions a very strong rotated cube texture is obtained very much similar to the one that is observed after cross rolling. After annealing, the rotated cube texture changes to a {h11}<1/h,21> fibre texture with a maximum on the {311}<136> component which implies the potential to develop a {001} fibre texture after further processing. It is argued that the appearance of the {311}<136> recrystallization texture component can be attributed to oriented nucleation in the vicinity of grain boundaries between slightly misoriented rotated cube grains.
Effect of Annealing on Microstructural Development and Grain Orientation in Electrodeposited Ni
Authors: Klement Uta , Hollang L. , Dey S.R. , Battabyal M. , Mishin O.V. , Skrotzki Werner
Published: March 2010

Thick (up to 5 mm) Ni electrodeposits were produced by the pulsed electrodeposition (PED) technique. The PED-Ni was investigated in planar and cross-sections using high resolution scanning electron microscopy. Grain size and local texture were studied by electron backscatter diffraction. Thermal stability and grain growth behaviour were investigated using in-situ annealing in the transmission electron microscope. It is observed that columnar grains are present in the material and that the orientation of grains is not uniform. Textures and in-situ annealing behaviour are compared to previous data on nanocrystalline PED-Ni and Ni-Fe, where a subgrain coalescence model adopted from recrystallization is used to describe the occurrence of abnormal grain growth upon annealing and where twinning was found to be responsible for the texture development.
Formation of Goss Texture in Grain Oriented Electrical Steel Sheets Produced by Commercial Compact Strip Processing
Authors: Mao W. , Li Y. , An Z. , Zhu G. , Yang Ping
Published: March 2010

The compact strip processing technology and the technologies for conventional grain oriented electrical steels were used to process the low cost grain-oriented electrical steel successfully, in which the reheating temperature for hot rolling was about 1150 oC, and strong Goss texture was obtained after the secondary recrystallization. It is indicated that the density of inhibitor particles produced under the condition of low temperature hot rolling was high enough to induce the necessary secondary recrystallization during final annealing, so that many Goss grains could grow. The mis-orientations of Goss grains to the recrystallization matrix were calculated and observed. High angle boundaries enveloped frequently Goss grains, while the growth of other grains would have the possibility to meet low angle boundaries or low mobile boundaries. Goss grains neighboring larger size grains might be protected by the further precipitation of inhibitor particles in high angel boundaries during the temperature rising stage of the secondary recrystallization and survived somehow after the growth competition.
Location Depending Textures of the Human Dental Enamel
Authors: Raue Lars , Klein Helmut
Published: March 2010

Dental enamel is the most highly mineralised and hardest biological tissue in human body [1]. Dental enamel is made of hydroxylapatite (HAP) - Ca5(PO4)3(OH), which is hexagonal (6/m). The lattice parameters are a = b = 0.9418 nm und c = 0.6875 nm [1]. Although HAP is a very hard mineral, it can be dissolved easily in a process which is known as enamel demineralization by lactic acid produced by bacteria. Also the direct consumption of acid (e.g. citric, lactic or phosphoric acid in soft drinks) can harm the dental enamel in a similar way. These processes can damage the dental enamel. It will be dissolved completely and a cavity occurs. The cavity must then be cleaned and filled. It exists a lot of dental fillings, like gold, amalgam, ceramics or polymeric materials. After filling other dangers can occur: The mechanical properties of the materials used to fill cavities can differ strongly from the ones of the dental enamel itself. In the worst case, the filling of a tooth can damage the enamel of the opposite tooth by chewing if the interaction of enamel and filling is not equivalent, so that the harder fillings can abrade the softer enamel of the healthy tooth at the opposite side. This could be avoided if the anisotropic mechanical properties of dental enamel would be known in detail, hence then another filling could be searched or fabricated as an equivalent opponent for the dental enamel with equal properties. To find such a material, one has to characterise the properties of dental enamel first in detail for the different types of teeth (incisor, canine, premolar and molar). This is here exemplary done for a human incisor tooth by texture analysis with the program MAUD from 2D synchrotron transmission images [2,3,4].
The Exoskeleton of the American Lobster – From Texture to Anisotropic Properties
Authors: Raue Lars , Klein Helmut , Raabe Dierk
Published: March 2010

The exoskeleton of the crustacean Homarus americanus, the American lobster, is a biological multiphase composite consisting of a crystalline organic matrix (chitin), crystalline biominerals (calcite), amorphous calcium carbonate and proteins. One special structural aspect is the occurrence of pronounced crystallographic orientations and resulting directional anisotropic mechanical properties. The crystallographic textures of chitin and calcite have been measured by wide-angle Bragg diffraction, calculating the Orientation Distribution Function (ODF) from pole figures by using the series expansion method according to Bunge. A general strong relationship can be established between the crystallographic and the resulting mechanical and physical properties.
EBSD-Based Dislocation Microscopy
Authors: Adams Brent L. , Gardner Calvin J. , Fullwood David T.
Published: March 2010

Recent advances in high-resolution electron backscatter diffraction (EBSD)-based microscopy are applied to the characterization of incompatibility structures near the grain boundaries (GBs) in polycrystals. The principal interest described here is recovery of geometrically-necessary dislocation (density) tensors, of the 2- and 3-D type, described by Nye and Kröner. These developments are presented in the context of the continuum dislocation theory. High resolution data obtained near a single grain boundary in well-annealed, low content steel suggests that it may be possible to measure the intrinsic elastic properties of GBs.
Texture Formation during Hot-Deformation of High-Nb Containing γ-TiAl Based Alloys
Authors: Stark A. , Schimansky Frank Peter , Clemens Helmut
Published: March 2010

In this study texture and microstructure formation in high-Nb containing TiAl alloys during lab-scale compression experiments and “near conventional” forging on an industrial scale are investigated. The deformation temperatures range from 700 °C up to temperatures close to the α transus temperature (Tα = 1295 °C). Depending on the deformation conditions, the texture of the tetragonal γ-TiAl phase is formed by pure deformation components, components related to dynamic recrystallization, or transformation components. This changing corresponds with microstructural observations. The hexagonal phases α2-Ti3Al and α-Ti(Al) show a similar texture as it is known for Ti and Ti-base alloys after compressive deformation at elevated temperatures. In contrast to the γ texture, no significant change of the α/α2 texture was observed in the investigated temperature range. In the alloy with a composition of Ti-45Al-10Nb (in at.%) even deformation textures of ternary intermetallic phases, as the hexagonal ωo-Ti4Al3Nb and the cubic βo-TiAl(Nb) phase, respectively, were measured and analyzed.
Texture Heterogeneity in ECAP Deformed Copper
Authors: Skrotzki Werner , Tränkner Christine , Chulist Robert , Beausir Benoît , Suwas Satyam , Tóth László S.
Published: March 2010

Polycrystalline copper of 4N purity has been deformed by equal channel angular pressing at room temperature using route BC. Local textures have been measured by high-energy synchrotron radiation along 3 lines in the cross section from the top to the bottom of the billets. The texture heterogeneity observed in the cross section is presented for 2 passes and discussed with regard to friction-affected material flow.
Structure Stability and Magnetic Properties of Ni2XGa (X = Mn, Fe, Co) Ferromagnetic Shape Memory Alloys by DFT Approach
Authors: Bai Jing , Raulot Jean Marc , Esling Claude , Zhao Xiang , Zuo Liang
Published: March 2010

In this paper, we report some ab initio calculation results of three perfect stoichiometric alloy systems Ni2XGa (X = Mn, Fe, Co). The calculations have been performed on optimizing the crystal structures in both austenitic and martensitic phases, the electronic density of states (DOS), the magnetic properties and the difference of charge distributions on considering that Mn, Fe, Co are adjacent to each other within one period in the periodic table of elements, and they are all ferro-magnetic. We have shown the impact of these magnetic elements on several properties of each alloy. Study on these three Heusler alloy systems is important in view of property prediction.
Frequencies of Tilt and Twist Boundaries among Random Grain Boundaries
Authors: Morawiec Adam
Published: March 2010

There are a number of classifications of homophase grain boundaries. It is quite common to divide them into twist, tilt and general boundaries. As in the case of the classification into coincident lattice (CSL) boundaries and non-CSL boundaries, one may ask about the possible frequencies of incidence of tilt and twist boundaries in a set of “random” boundaries. The proba¬bilities of occurrence of these particular boundary types are clearly defined if small deviations from pure twist and tilt conditions are allowed. We estimated the probabilities numerically for the cases of cubic and hexagonal holohedries. For a given randomly generated boundary, a computer program searched for the nearest pure-tilt and pure-twist boundaries. All symmetrically equivalent representations of the random boundary were processed, and the smallest distance was taken as the result. The distance was based on both the difference in misorientations and the deviation between boundary inclinations. The findings concerning tilt boundaries turned out to be striking. For instance, if the allowed deviation from pure-tilt conditions is only 1°, then as many as 39.0% and 21.2% of random boundaries have near-tilt character for the cubic and hexagonal cases, respectively. If the limiting deviation is raised to 5°, the frequencies of near-tilt boundaries reach 98.6% and 77.0%, respectively.
Transcriptional Repressor BCL6 Controls Th17 Responses by Controlling Gene Expression in Both T Cells and Macrophages
Authors: Mondal Arpita , Sawant Deepali , Dent Alexander L.
Published: March 2010

The transcriptional repressor protein BCL6 regulates T cell differentiation by repressing Th2 responses and promoting follicular Th cell responses. However, little is known about the role of BCL6 in Th17 responses. We found that memory T cells from BCL6-deficient mice had increased IL-17 production. Additionally, BCL6 expression is upregulated in CD4 T cells cultured under Th17 conditions. T cells from BCL6-deficient mice showed defective Th17 differentiation and enhanced IL-4 production in vitro; however, normal Th17 differentiation was obtained with BCL6-deficient T cells under culture conditions when highly pure naive CD4 T cells were used, when IL-4 production was inhibited, or when TGF-β levels were increased. Retrovirus-mediated expression of BCL6 in CD4 T cells repressed IL-4 and augmented basal IL-17 mRNA expression. These data support the idea that BCL6 promotes Th17 differentiation through suppression of Th2 differentiation. BCL6-deficient T cells transplanted into Rag1−/− mice produced wild-type levels of IL-17, indicating that, in vivo, BCL6-deficient T cells develop relatively normal Th17 responses. Macrophages from BCL6-deficient mice showed strikingly increased expression of the Th17-promoting cytokines IL-6, IL-23, and TGF-β, and conditioned media from BCL6-deficient macrophages promoted augmented IL-17 expression by T cells. We propose that the increased Th17 activity in BCL6-deficient mice is due, in part, to BCL6-deficient macrophages promoting increased Th17 differentiation in vivo. T cells may require BCL6 for optimal Th17 differentiation; however, BCL6 function in macrophages critically regulates Th17 differentiation in vivo. We hypothesize that increased Th17 differentiation aggravates the severe Th2-type inflammatory disease in BCL6-deficient mice.
CD8 T Cells Activated in Distinct Lymphoid Organs Differentially Express Adhesion Proteins and Coexpress Multiple Chemokine Receptors
Authors: Ferguson Andrew R. , Engelhard Victor H.
Published: March 2010

Previous work from this laboratory showed that generation of memory CD8 T cells by different immunization routes correlates with control of tumors growing in distinct sites. We hypothesized that effector CD8 T cell expression of adhesion proteins and chemokine receptors would be influenced by activation in different secondary lymphoid organs. In this report, CD8 T cells were activated by immunization with bone marrow-derived dendritic cells via i.p., i.v., or s.c. routes. Three distinct populations of activated CD8 T cells arise in mesenteric, axillary/brachial, and mediastinal lymph nodes and spleen based on differential expression of α4β7 integrin, E-selectin ligand, and α4β1 integrin, respectively. In contrast, three subsets of CD8 T cells defined by differential expression of P-selectin ligand and chemokine receptors were induced irrespective of activation site. The majority of activated CD8 T cells expressed CXCR3, with one subset additionally expressing P-selectin ligand, and another subset additionally expressing CCR3, CCR4, CCR5, CCR6, and CCR9. In the mesenteric lymph node, a fourth subset expressed CCR9 and CXCR3 in the absence of CCR5. Similar homing receptor profiles were induced in the same sites after localized vaccinia immunization. Homing receptor expression on CD8 T cells activated in vitro was distinct, revealing influences of both dendritic cells and the lymphoid microenvironment. Collectively, these results identify previously undescribed populations of activated CD8 T cells based on adhesion protein expression and coexpression of chemokine receptors that arise after activation in distinct secondary lymphoid organs.
Application of the Assimilation and Dissimilation (A-D) Test to Observe the Toxic Effect in Superficial Waters
Authors: Chiochetta Claudete Gorczevski , Chiochetta Michel
Published: March 2010

The A-D Test is a combination of orientation tests, based on the toxic effects of basic the autotrophic and heterotrophic processes in an aquatic ecosystem. The present work has as objective the interpretation of the oxygen production inhibition in Cloroficeas mixing cultures and the oxygen consumption in bacterium cultures, as a toxicity superficial water evaluation criterion. The inhibition values of oxygen production increase according to the concentration of water in the stream and the substance presence in suspension. In the Dissimilation Tests the values of CBO inhibition of the bacterium are about 10%, considered NOEL in the A-D Test. Then the conclusion suggests the necessity of an adaptation and improvement of the Dissimilation Test.
Linear Alkylbenzene Sulfonate Toxicity Removal Treated by Electron Beam Radiation
Authors: Romanelli Maria Fernanda , Silva G. P. , Borrely Sueli I.
Published: March 2010

Surfactants, as detergent active substances, are also an important source of pollution causing biological adverse effects to aquatic organisms. The presence of surfactants may cause serious ecological disturbances, so affecting aquatic organisms, including fishes. Several studies have demonstrated the efficiency of effluent treatment with electron beam that can contain organic compounds as contaminants, and a big reduction being observed after the treatment. In the present work acute and chronic toxicity tests were performed with the organisms Daphnia similis, Vibrio fischeri and Ceriodaphnia dubia for the toxicity evaluation caused by the surfactant dodecyl p-benzenesulphonate acid, LAS, that is the most used anionic surfactant worldwide, in distilled water. The LAS solution was treated with electron beam in order to study the degradation of this surfactant by the ionizing radiation and the percentage of the acute and chronic toxicity reduction. The results obtained showed a acute toxicity reduction between 30.04% and 68.94% and between 45.70% and 64.99% for the chronic toxicity, using radiation doses of 3.0 kGy, 6.0 kGy, 9.0 kGy and 12.0 kGy. The doses of 3.0 kGy and 6.0 kGy were the most effective for the toxicity reduction of LAS. The concentration reduction, in mg/L, due to the cleavage of the surfactant molecule by the ionizing radiation, was monitored by the Methylene Blue Method, also known as MBAS. The ionizing radiation showed high efficiency for the concentration and toxicity reduction of the surfactant that was studied.
Ecotoxicological Assessment of the Sediment in Arroio Sapucaia, RS, Brazil, Using Different Sampling Devices and Test Organisms
Authors: Portela Carina M. S. , Arenzon A. , Raya-Rodriguez M. T.
Published: March 2010

Assessment of sediment quality in Arroio Sapucaia, a stream in the state of Rio Grande do Sul, Brazil, was conducted at four locations along its course with use of two sampling devices (Eckman grab and “corer hand”) and two species of test organisms (Hyalella azteca and Ceriodaphnia dubia). This evaluation was performed from March/2000 through January/2001, using toxicity essays based on standard methodology. According to results of this study, there was no significant difference between sampling devices, with the exception of the first sampling location. Ecotoxicological evaluation containing benthic (H. azteca) and plankton (C. dubia) organisms indicate that results depend on which test organism is used, since three of the total sampling locations showed significant difference. In general, according to toxicity essays, monitoring results for Arroio Sapucaia indicate an increase in environmental deterioration along its sampling locations, from upstream to downstream.
Productivity and Sensitivity of Daphnia similis and Daphnia magna in Different Cultivation’s Aspects
Authors: Beatrici Aline Cristina , Arenzon A. , Coimbra N. J. , Raya-Rodriguez M. T.
Published: March 2010

Various aspects of cultivation may influence an organism’s productivity and sensitivity. This research focuses on evaluating the effects of different diets and cultivation media on sensitivity and reproduction of D. similis and D. magna. Diets consisted of Pseudokirchneriella subcapitata at 1.5.105 cells.ml–1 and Scenedesmus subspicatus at 106 cells.ml–1. This algae combination was supplemented with a trout or Artemia feed. During twenty one days the mean number of neonates per female were observed daily for each treatment. Simultaneously to this, potassium dichromate sensitivity essays were also performed, according to NBR 12713, for each diet. Results on fertility was not significantly altered while using a diet of P. subcapitata for D. similis and S. subspicatus for D. magna, indicating Artemia feed as an alternative to M4 medium. Regarding sensitivity, every analyzed case showed more resistance to potassium dichromate when cultivated in ISO medium.
Assessment of the Heavy Metals in Paranaguá Bay, PR, Brazil, Influenced by Anthropic Activities
Authors: Santos Dayana Moscardi dos , Bossini J. A. T. , Preussler K. H. , Vasconselos E. C. , Carvalho-Neto F. S. , Carvalho-Filho M. A. S.
Published: March 2010

The study of heavy metals in the water column is fundamental, therefore it can contribute in a significant way for understanding the aquatic systems pollution, reassert itself into dangerous contaminants in local and global scale, leading to a stress of the aquatic communities and be associated to the chronic effect to human health. The present work had the aim of analyzing heavy metals found in the water in the Paranaguá Bay. The samples had been collected randomly around the Bay, totalizing ten samples. The opening of samples, using HNO3 was done. In each sample the concentrations of Ni, Fe, Se, Zn, Pb and Cu had been determined by the atomic absorption spectrophotometer method. Of all elements analyzed in the present study, only to Se was detected raised concentrations, above the limit stablished by CONAMA 20/86, being necessary the monitoring of this element in the environment and in its polluting sources.
Comparison Between Laboratory and “in Situ” Bioassays Using Chironomus xanthus in the Assessment of Sediment Toxicity in the Monjolinho River (São Carlos, SP)
Authors: Dornfeld Carolina B. , Espíndola E. L. G. , Fracácio R. , Rodrigues B. K. , Novelli A.
Published: March 2010

“In situ” bioassays (96 h), using Chironomus xanthus, were conducted in October/03 and January/04, in 4 sampling stations at Monjolinho river. Laboratory bioassays were conducted using 60g of sediment and 240 ml of ASTM medium, for 96 h. Six organisms were added to each test-chamber and the toxicity evaluation was given by the mean survival. The “in situ” bioassay test chambers (PVC) were covered by a 300 μm mesh. The sediment of each sampling station was added to the chambers together with 10 organisms at IV instars. The laboratory bioassays showed survivals ranging between 0% (Federal, Oct/03) and 100% (Federal, Jan/04). The results “in situ” bioassays showed high mortality (between 84% and 97% in Oct/03 and between 60% and 70% in Jan/04). However, the results did not show, necessarily, that the sediments were toxic or not, because of the high mortality that occurred in the river ́s spring (over 60%), which may be associated to other factors, like screen saturation with suspended matter and different sediment textures. The presence of indigenous organisms may have influenced the results, due the competition and predation in the chamber. Thus, we can infer that the protocol for “in situ” bioassays using C. xanthus must be improved in order to minimize the influence of confounding factors on the tests results.
Automotive Impact in Populations of Ctenomys minutus in the Coastal Plain in Southern Brasil: Evaluation of Heavy Metal Contents and Quantification of Lipoperoxidation Levels
Authors: Raya-Rodriguez Maria Teresa , Ferreira C. J. S. , Moreira J. C. F.
Published: March 2010

The present work aims to check the automotive traffic impact caused by analyze toxic metal concentration in environmental samples in areas near and far from the road and its correlation with lipoperoxides formation in population of Ctenomys minutus (tuco-tucos). Individuals were captured seasonally in three different traffic impact area. From each individual were collected blood to quantify lipoperoxidation by the biochemical assay TBARs (Tiobarbituric acid reactive). In samples of fur, spraints, soils and food vegetation were analyzed Cd, Ni, Pb and Zn. This study show significant difference of toxic metals in areas near the traffic road. The TBARs assay indicates strong seasonal differences. In summer, when the traffic road increase, the index injury was biggest in all the study areas and even greater near the road.
How Rural Producers Use Pesticides
Authors: Scatena Lúcia Marina , Duarte R. de G.
Published: March 2010

The purpose of this work was, after gathering information about the use of pesticides by rural producers, to develop teaching material on environmental education, in technical language appropriate to the target audience, with the aim of providing rural producers with the knowledge necessary to improve their quality of life. To characterize the profile of the community and better understand the positioning of small farmers regarding land use and occupation, production system and land structure, information was collected from federal, state and municipal agencies. The study was carried out in the Córrego da Capituva microbasin, municipality of Macedônia, SP, whose striking characteristic is the existence of small rural properties (sites of 1 to 10 ha, representing 36%, and of 10 to 50 ha, 47%) that , basically, use family labor (69% only family labor and 22% family labor and day laborers). The production profile is 67% based on beef and dairy farming and 16% on citrus. Pesticides are used by farmers as follows: 76% use pesticide products; 82% never used personal protective equipment when preparing grout; 83% never used protective equipment when applying the products; 5% rarely observe the re-entry period in the pesticide application areas; 8% usually supply spraying equipment in waterways; 5%, in some way, frequently reuse the empty packaging of these products; 54% follow technical guidance at the time of purchase; 35% seek guidance from other people; and 11% do it their own way. In the lectures with rural producers to apply the teaching material, it became clear that the current economic model justifies the use of pesticides due to the need for productive agriculture, capable of meeting the global demand for food and guaranteeing its own economic survival. The farmer also believes that pesticides only harm the health of those who are not used to it.
Assessment of the Lead Content in Perna perna Mussels in the Metropolitan Region of the Rio de Janeiro City
Authors: Maia Cristina Baptista , Almeida A. C. M. , Moreira F. R.
Published: March 2010

Guanabara Bay is the most important estuarine system in Rio de Janeiro City and receives the most untreated effluents of the city. As a consequence of this impact the beaches in the metropolitan zone are heavily polluted. Bivalves mollusks are able to store a wide variety of pollutants from very diluted solutions without visible damage. The Perna perna mussel is a bivalve organism that accumulates metal and thus it is considered an environmental pollution indicator. Native from the region, this species is consumed in the diet by poor people since it is easily available. Lead is one of the most common pollutants in the environment. It is considered toxic to human beings and animals and without any physiological known function in the organism. Lead toxic effects can affect almost all organs and systems of the body. In this work electro-thermal atomic absorption spectrometry was used to determine lead concentration in Perna perna mussels collected at Flamengo, Vermelha and Vidigal beaches located in the metropolitan region of the Rio de Janeiro City. The mean lead concentration found was (2.0 ± 0.93 mg.kg–1) almost 10 times greater than that found for non exposed mussel, used as the control group from Penha (SC). This value is the upper limit allowed by the Brazilian legislation (2.0 mg.kg–1), meaning a risk to those people with a rich diet in mussels.
Toxicopathological Evaluation of Rats Exposed to Pseudomonas putida
Authors: Castro Vera Lúcia S. S. de , Melo I. S. de
Published: March 2010

Pseudomonas putida has been show useful for the bioremediation of various xenobiotics, but there is little information related to its security to human health. It was investigated the effects of P. putida involved in the herbicide propanil biodegradation in rats, in order to evaluate possible toxicopathological effects promoted by the bacteria exposure. Rats were exposed at a single oral dose of 108 cfu mL–1. The animals were observed daily, not having clinical alterations at different intervals after the exposure. They were sacrificed and necropsied at these intervals and samples of various organs were removed to verify the bacteria presence on them. P. putida was not able to grow after 3 and 24 hours after exposure. However it was founded colonies of the agent 16 h after the exposure in lung homogenates. Confirmation of the diversity of bacteria was performed with the fatty acid methyl esters procedure. The protocol utilized showed to properly evaluate the security of this agent to mammals.
Barnacle Larvae of Megabalanus coccopoma (Darwin, 1854) as a Toxicity Test Organisms
Authors: Souza R. Camargo , Poleza F. , Máximo M. V. , Resgalla Jr. Charrid
Published: March 2010

In Brazil, Marine Ecotoxicology is a retelatively new science with few species routinely used in toxicity tests. Barnacle larvae (Naupliu) have been used for different research groups in the world as test organisms with a variety of methods and applications. These organisms have the advantages of easy obtainment in the field, availability throughout the year and easy manipulation in the lab. The use of these organisms in Brazil is still limited to tests of the activity of anticrustant substances and few work has been done to investigate their sensitivity as test-organisms in Ecotoxicology. This work presents a standard operating procedure to perform toxicity tests with naupliu of the barnacle Megabalanus coccopoma one of the biggest examplers of the subordem Balanomorpha and of great distribution around the Brazilian coast. The sensitivity of naupliu II to Zinc (Zn) was evaluted through mobility and mortality endpoints. Nauplius of the M. coccopoma were obtained from egged lamels of adults and used in 48 hours toxicity tests to assess the effect of zinc sulphate in static experimental conditions; poorly mobile and dead organisms were quantified every 12 hours. On the mobility tests, the EC50 of 0.24 mg L–1 (Zn) was obtained following 24 hours expousure; whilst the LC50 of 0.27 and 0.22 mg L–1 (Zn) were obtained following 36 and 48 hours of exposure, respectively. Significant differences were not observed between the EC50 and LC50 values for zinc therefore allowing the development of 24 h mobility and 48 h mortality tests. The EC50; 24 h and LC50; 48 h for zinc demonstrate similar sensitivity between the studied species the mysids Mysidopsis juniae and the copepod Acartia lilljeborgi.
Kidney Histology of Mice After Seven Days Oral Intake of Cyanobacterial Extract
Authors: Carvalho Elisa Garcia , Sotero-Santos R. B. , Martinez C. B. R. , Freitas E. C. , Fenerich-Verani N. , Dellamano-Oliveira M. J. , Rocha O.
Published: March 2010

At the end of the dry season, during October 2004, a dense cyanobacteria bloom was observed in Monjolinho Reservoir (São Carlos city, São Paulo State, Brazil), and a great amount of scum accumulated on the water surface. Samples were collected in order to identify phytoplankton species and to determine its toxicity. Anabaena circinalis and Anabaena spiroides were the dominant species in this bloom. Initially, mouse bioassays (LD50-24 h) and analysis by ELISA were performed, to detect toxic compounds in crude extracts of the natural samples. After toxicity was confirmed, an oral chronic toxicity test was carried out using three doses of cyanotoxins, in male Swiss albino mice, for 7 days. To prepare the extract, cyanobacterial cells were broken by repeated freeze and thaw cycles. Mice received the following doses of crude cyanobacterial extract diluted in drinking test solutions: 0.5 mg L–1; 1.0 mg L–1 and 2.0 mg L–1. Mortality, clinical signs, body weight and weight gain were recorded during the study. In addition, histological slides were prepared to detect toxic injuries to the kidney. Toxin analysis by ELISA revealed 1.77 to 6.12 μg L–1 total microcystins in the mouse drinking water. This study indicated that administration of low doses of cyanotoxins in mouse drinking test solutions did not result in histological injury in the kidney of animals exposed to cyanotoxins, as observed by optical microscopy.
Evaluation of Genotoxicity Induced by Atmospheric Pollution Using the Land Mollusk Cantareus aspersus (Müller, 1774) as Biomonitor and the Comet Assay as Biomarker
Authors: Silva Juliana da , Simeoni N. , Groff A. A. , Ianistcki M. , Benvegnú V. , SCHRÖDER N. T.
Published: March 2010

The objective of this work was to investigate the viability of using the land mollusk Cantareus aspersus (Müller, 1774) as biomonitor and the Comet Assay as biomarker, exposing organisms to atmospheric pollutants. Organisms were exposed to air at the Ulbra University campus climatic control station (Canoas, RS) for 7, 15 and 30 days, in the winter/2004 and in the summer/2005. Our control group, not exposed, was kept in the laboratory, under controlled conditions. Lung cells and hemolymph cells were evaluated through Comet Assay, which shows sensitive results in a short time in quantifying lesions and detecting DNA repair effects. 100 cells/individual/tissue were analyzed and visually classified into five classes (0 – no effect to 4 – maximum damage). Results show that pulmonary cells are more sensitive than hemolymph cells. Longer exposition time produced more DNA damage. Considering climatic seasons, no significant differences were detected between them. Both organisms and method showed to be cheap, effective and sensitive in our study, for biomonitoring atmospheric pollution.
Biochemical Biomarkers in Individual Larvae of Chironomus xanthus (Rempel, 1939) (Diptera, Chironomidae)
Authors: Printes Liane Biehl , Espíndola E. L. G. , Fernandes M. N.
Published: March 2010

Biochemical biomarkers have shown to be useful toxicity tools in environmental assessment programmes. However, few studies involving freshwater invertebrate species have been performed and even fewer on tropical species. The aim of this paper was to evaluate cholinesterase (ChE) and glutathione-S-transferase (GST) activities in larvae of Chironomus xanthus (Chironomidae, Diptera) exposed to the organophosphate parathion (ethyl) and the metals copper and cadmium. Considering ChE, significant reduction in activity was observed following C. xanthus exposure to parathion and cadmium (48 and 96 h, respectively). Inhibition of ChE activity (IC50) related to parathion seemed to be a more consistent and sensitive effect criteria than the LC50. For GST, there was significant reduction in activity following parathion exposure (48 h). Copper did not elicit any change in ChE or GST activities in C. xanthus. The findings of this paper show the two biomarkers as promising tools for assessing exposure to contaminats in tropical regions.
Mercury in the Plankton of an Amazon Natural Lake, Puruzinho Lake (Brazil)
Authors: Nascimento Elisabete Lourdes do , Gomes J. P. O. , Almeida R. , Bastos W. R. , Bernardi J. V. E. , Miyai R. K.
Published: March 2010

This study has the objective of evaluating the total mercury concentrations (Hg) in plankton samples of Puruzinho Lake, which is located on the left margin of the Madeira River, 20 km downstream of the Humaitá city (Amazon state, Brazil). Three samples were taken at a central part of the lake (S07°22’19.2”; W063°02’32.2”) during rainy (February 2004 and May 2005) and dry (October 2004) seasons. Plankton samples were collected using two nets of nylon. An aliquot of each plankton filtrate was preserved for posterior plankton identification, and another lyophilized for Hg analysis. The total mercury was determined by atomic absorption spectrophotometry and cold vapor generation (FIMS-400). The highest concentration of mercury in the plankton was observed in February of 2004 (337 μg kg–1), the rainy period. Levels in the plankton were comparable to those from regions considered contaminated by Hg. Inputs of mercury are likely to happen due to run off after soil flooding during the rainy season, which also turn this metal available to the planktonic community.
Sensitivity of Four Test Organisms (Chironomus xanthus, Daphnia magna, Hydra attenuata and Pseudokirchneriella subcapitata) to NaCl: an Alternative Reference Toxicant
Authors: Santos Maria Alice P. F. dos , Vicensotti J. , Monteiro R. T. R.
Published: March 2010

In order to establish a safer reference toxicant for use in monthly sensitivity tests at the Ecotoxicology Laboratory (CENA-USP, Brazil), sodium chloride (NaCl p.a.) was evaluated as a possible surrogate for metals during a period of two years with the following test organisms: Chironomus xanthus, Daphnia magna, Hydra attenuata and Pseudokirchneriella subcapitata. All tests were performed following protocols most commonly used for each species. Mean endpoint values obtained were: LC50(96 h) = 5.84 g L–1 (426.9 μS cm–1) for C. xanthus, LC50(48 h) = 5.55 g L–1 (461.5 μS cm–1) for D. magna, LC50(96 h) = 2.57 g L–1 (245.6 μS cm–1) and EC50(96 h) = 1.44 g L–1 (147.2 μS cm–1) for H. attenuata, and IC50(72 h) = 0.87 g L–1 (85.3 μS cm–1) for P. subcapitata. Results indicate good reproducibility, as acceptable coefficients of variation were obtained: 17.03%, 15.02%, 14.84%, 15.28%, and 20.08%, respectively. These results agree with those obtained by other authors, for the same test organisms, using metals such as potassium dichromate. Based on these data, it was possible to conclude that sodium chloride constitutes an adequate alternative reference toxicant to metals, for routine sensitivity tests.
Acute Toxicity of Mercury Associated to Selenium, to Minnows Tilápia Oreochromis niloticus
Authors: França Jakeline G. de , Lombardi J. V. , Ranzani-Paiva M. J. T. , Carvalho S. de
Published: March 2010

The aim of this study was to evaluate if the two forms of selenium (sodium selenite – Se4+ and sodium selenate – Se6+) have antagonistic effect on the acute action of mercury chloride (HgCl2) by toxicity acute tests, using minnows of tilapia, Oreochromis niloticus as test-organisms. The treatments consisted of: I) control group; II) only Hg; III) only Se4+; IV) only Se6+; V) Se4+ + Hg; and VI) Se6+ + Hg. The following concentrations were used in the test: 0.4 mg L–1 of Hg (considered as lethal median concentration – LC50) and 1.0 mg L–1 of Se (considered as non lethal effect concentration – NOEL) for two selenium forms. After 24 hours of exposition to the treatments that contained mercury, the fish presented clinical signals of poisoning, such as: hyperactivitiy, skin darkness, swimming disorder, difficulty for breathing, and death. There were no differences statistically significants (p > 0.05) in the mortality between the treatments II-V, and II-VI, indicating the absence of antagonistic effect between these elements. Results discussed in this paper suggest that the concentration of Se (NOEL) used in the present study perhaps has exceeded the molecular ratio of 2.5 : 1/(Hg : Se) supposedely considered as suitable for interacting atagonisticaly in the toxicity of mercury.
Development of a Site-specific Ecological Risk Assessment Scheme for Tropical Environments: a Case Study From Santo Amaro da Purificação, Bahia, Brazil
Authors: Niemeyer Júlia Carina , Da Silva E. M. , Sousa J. P.
Published: March 2010

This project aims to further develop and adapt an ecological risk assessment scheme, following a tiered approach, for tropical systems. The study will be conducted in a metal contaminated area at Santo Amaro da Purificação (Bahia, Brasil), resulting from the deposition of reminiscent metal waste of a lead smelter, inactive since 1993. The ecological risk will be evaluated joining information from three different lines of evidence: chemistry, ecology and ecotoxicology. The study includes the development and adaptation of terrestrial ecotoxicological bioassays for tropical environments that, together with bioassays with aquatic organisms, will allow an integrated assessment of both habitat and retention functions of the impacted soils. The final output of the project will be an environmental risk assessment scheme that will act as a base scheme for tropical environments with similar contamination profile.
Cadmium Accumulation by Water Hyacinth and Salvinia Under Different Sulfur Concentrations
Authors: Vestena S. , Cambraia José , Oliva M. A. , Oliveira J. A.
Published: March 2010

Cadmium (Cd) accumulation by water hyacinth and salvinia under different sulfur (S) concentrations was studied. Plants were exposed during six days to 0 and 5 μM of Cd in nutrient solution with 0, 400 and 800 μM of S, and then S and Cd contents in tops and roots were determined. Sulfur content was always higher in S-treated plants, independent of the presence of Cd. Cadmium content in Cd-treated plants increased with the addition of S to the nutrient solution in both species. Water hyacinth roots accumulate an average of 1.4 time more Cd than those of salvinia. The increase in S concentration from 400 to 800 μM, however, usually did not result in additional increase in S nor in Cd accumulation. The molar Cd/S ratio after Cd treatment reached average values of about 4.8 in roots and 2.6 in tops in comparison to their respective controls. Both species, therefore, were Cd accumulators and the accumulation was larger in the roots under presence of S. Since water hyacinth produced larger root mass and accumulated more Cd, it showed larger capacity to remove Cd from aquatic systems contaminated with this metal, especially if S is available.