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Aquatic ecosystems have biological, social, and economic importance. Between the 1980s and 2000s, a few theoretical concepts emerged that attempt to provide a better understanding of the function and dynamics of freshwater ecosystems, including biotic and abiotic variables. The rationale for our research was based on observations of the distribution and abundance of an exotic bivalve mollusc, the golden mussel Limnoperna fortunei (Dunker, 1857). The species has been recorded from several river basins, but only occurs in large water bodies and fails to reach first-order streams. This study provides an overview of the main stream ecology concepts developed to explain the dynamics of lotic ecosystems in an attempt to solve this paradox. The river continuum concept was the first of many in river ecology. These theoretical concepts are not mutually exclusive, but interdependent. It is expected the main reasons for the non-occurrence of L. fortunei in small streams are twofold: fluctuations in physical and hydrologic conditions in small streams, generating instability, and reduced availability of plankton in first- and second-order streams.

Background Limnoperna fortunei is a freshwater bivalve mollusc originally from southern Asia that invaded South America in the 1990’s. Due to its highly efficient water pumping and filtering, and its capacity to form strong adhesions to a variety of substrates by byssus thread, this invasive species has been able to adapt to several environments across South America, causing significant ecological and economic damages. By gaining a deeper understanding of the biological and ecological aspects of L. fortunei we will be able to establish more effective strategies to manage its invasion. The gills of the mollusc are key structures responsible for several biological functions, including respiration and feeding. In this work, we characterized the ultrastructure of L. fortunei gills and its ciliary epithelium using light microscopy, transmission and scanning electron microscopies. This is the first report of the morphology of the epithelial cells and cilia of the gill of L. fortunei visualized in high resolution. Results The analysis showed highly organized and abundant ciliary structures (lateral cilia, laterofrontal cirri and frontal cilia) on the entire length of the branchial epithelium. Mitochondria, smooth endoplasmic reticulum and glycogen granules were abundantly found in the epithelial cells of the gills, demonstrating the energy-demanding function of these structures. Neutral mucopolysaccharides (low viscosity mucus) were observed on the frontal surface of the gill filaments and acid mucopolysaccharides (high viscosity mucus) were observed to be spread out, mainly on the lateral tract. Spherical vesicles, possibly containing mucus, could also be observed in these cells. These findings demonstrate the importance of the mucociliary processes in particle capture and selection. Conclusions Our data suggest that the mechanism used by this mollusc for particle capture and selection could contribute to a better understanding of key aspects of invasion and also in the establishment of more efficient and economically viable strategies of population control.

O Limnoperna fortunei (Dunker, 1857) é um bivalve invasor, nativo do Sudeste da Ásia, vem ganhando espaço ao redor do mundo. Apesar dos danos causados, poucos trabalhos relatam reprodução em laboratório. O presente trabalho tem como objetivo relatar eventual reprodução do L. fortunei em condições laboratoriais parcialmente controladas. As coletas dos colonizatórios ocorreram de janeiro a abril de 2021. As amostras foram aclimatadas em aquários com capacidade total de 30 a 500 litros. Foram observados filamentos brancos nos aquários de amostras recentes. Os autores associam essa substância com células gaméticas. Cerca de dois a cinco meses após a visualização dos filamentos, foram identificados indivíduos de diferentes tamanhos: 0,1 a 6 mm, enquanto os organismos da amostra colonizadora apresentavam tamanho entre 1 e 2 cm. O surgimento das substâncias brancas filamentosas e o achado de organismos de tamanhos distintos, associados à visualização microscópica de forma jovens, são indicativos de possível reprodução do mexilhão dourado em laboratório.

Mollusca e um dos maiores Filos do Reino Animal, com uma estimativa de 240.000 especies. O grupo apresenta enorme diversidade biologica, atrelada a ampla distribuicao geografica. Os representantes do Filo apresentam distintos nichos e relacoes troficas. Algumas especies sao de interesse economico e outras de saude publica. Um exemplo e o Limnoperna fortunei Dunker, 1857, que condiciona prejuizo ambiental, social e economico. Ja o genero Biomphalaria , hospedeiro intermediario de um trematodeo, causa problemas de saude publica em muitos paises. Atualmente, o Filo e representado por oito classes: Solenogastres ou Neomeniomorpha, Caudofoveata ou Chaetodermomorpha, Polyplacophora, Bivalvia, Monoplacophora, Scaphopoda, Gastropoda e Cephalopoda. Diante disso, o presente trabalho teve como objetivo realizar um trabalho de revisao do atual conhecimento das caracteristicas do Filo Mollusca. Mesmo diante dessa diversidade e importância, algumas informacoes sao escassas e pulverizadas na literatura.

O uso de agrotóxicos se faz cada vez mais presente nas atividades agrícolas, sendo o Brasil um dos maiores contribuintes ao uso glifosato (N-fosfonometil glicina). A utilização inadequada de defensivos agrícolas oferece potencial risco ao meio ambiente, principalmente em ambientes aquáticos continentais. Nesse sentido, o objetivo deste trabalho foi realizar teste de toxicidade com o gastrópode límnico Physa acuta na intenção de verificar os efeitos das concentrações do Glifosato 480 AGRIPEC®. Os organismos utilizados no teste de toxicidade são oriundos do cultivo de moluscos dulcícolas no Biotério Nico Nieser, do Laboratório de Ecologia e Evolução da Universidade Federal do Triângulo Mineiro (UFTM). Foram escolhidos aleatoriamente vinte e quatro gastrópodes e alocados dois indivíduos por aquário, totalizando onze unidades experimentais. O experimento foi acompanhado por quatorze dias. O tratamento 1, com a maior concentração de glifosato (1ml) exibiu 100% de mortalidade em relação aos demais tratamentos. Quando comparado a porcentagem de sobrevivência de todos os tratamentos, pode-se verificar dois grupos: tratamentos 1-5 apresentaram 60% de sobrevivência, enquanto os tratamentos 6-10 apresentaram 90%. Dessa maneira, ficou evidenciado que as concentrações de glifosato podem estar relacionadas com a porcentagem de sobrevivência, quanto menor a concentração do herbicida maior a porcentagem de sobrevivência. Esses dois grupos apresentaram diferenças estatisticamente significativas. Os autores concluem que apesar dos resultados indicarem a toxicidade do glifosato ao Physa acuta, novos estudos devem ser realizados visando identificar o real grau de toxicidade e eventual DL50 do princípio ativo.

Limnoperna fortunei, the golden mussel, is a bivalve mollusc native to Southeast Asia, which was introduced to South America via ballast water from commercial cargo ships from China and South Korea. In Brazil, the golden mussel is considered an invasive species, which has caused enormous economic and environmental damage. This is mainly due to the obstruction of pipes carrying water for the cooling systems within hydroelectric power plants. The presence of this invasive species also negatively impacts native fauna and flora. Early detection and rapid response during the early stages of infestation for this invasive species is essential to effectively control populations and prevent new infestations from forming. Techniques within molecular biology allow for more efficient detection of the golden mussel in all stages of development. In addition, the analysis of the genome, transcriptome and proteome of this species makes it possible to identify targets of biotechnological interest, which may be useful for the control of the golden mussel or for the generation of products of technological innovation. This review presents an overview of molecular studies involving this species and the perspectives on the prevention, control and combat of the golden mussel using these approaches.

Introdução: Espécies não nativas invasoras são aquelas que ocorrem fora de sua área de distribuição natural, e apresenta uma expressiva capacidade de distribuição na nova região ocupada e apresentam vantagens ecológicas (Interações bióticas e abióticas) em relação às espécies nativas. Nesse sentido, as espécies exóticas invasoras causam impacto ambiental e econômico. Objetivo: O presente trabalho objetivou levantar a malacofauna invasora no rio Grande. Materiais e Métodos: Foram realizadas coletas de 09 a 17 de dezembro de 2020, divididas em quatro campanhas. Foram amostrados sete pontos ao longo do rio Grande e o tributário Córrego Gameleira. Os pontos estão distribuídos nos municípios de Uberaba-MG (ponto 1); Água comprida-MG (pontos 2 e 6); Igarapava-SP (ponto 3), Delta-MG (pontos 4 e 5), Miguelópolis-SP (ponto 7). Para a amostragem biótica, foram realizadas cinco amostras aleatórias de sedimentos em cada ponto. Para isso foi utilizado um amostrador de mão (método dipping). Os materiais capturados foram acondicionados em sacos plásticos com 500 ml de formol. Em laboratório, os sedimentos foram lavados e triados em tamises de 2, 1 e 0,5 mm. Os organismos foram identificados com auxílio de livro de identificação específico. Nessa etapa também foi utilizado o estereomicroscópio. Resultados: Foram amostrados 342 indivíduos distribuído entre as duas classes: gastrópode e bivalve. A espécie mais abundante foi o Limnoperna fortunei (Dunker, 1857) com 307 (89,7%) indivíduos. Melanóides Turberculata (Müller, 1774) apresenta a segunda maior abundância com 53 exemplares (15,4%). O menos abundante foi Corbicula Fluminea (Müller, 1774) com 39 representantes (11,4%). Conclusão: O ponto 2 foi o local que apresentou a maior riqueza de espécie dentre todos os pontos amostrados. Esse ponto é o único que apresenta mata ciliares densas em ambos lados das margens. Pode-se inferir que a riqueza de espécie é dependente das características ambientais.

INTRODUÇÃO: O Filo Mollusca (do latim, molluscus = mole) é unanimemente aceito como um grupo monofilético. Esse grupo é segundo maior Filo do Reino Animal, com uma estimativa de 240.000 espécies, atrás apenas do Filo Arthropoda. Os moluscos apresentam uma enorme diversidade biológica, com distintos nichos e interações ecológicas. Esses fatores podem estar atrelados a ampla distribuição geográfica. Adicionalmente a isso, algumas espécies são de interesses econômicos e outras de saúde pública. OBJETIVO: O presente trabalho teve como objetivo realizar uma revisão bibliográfica das características gerais do grupo, bem como das Classes que compõem o Filo. MATERIAIS E MÉTODOS: A metodologia utilizada foi baseada em revisão bibliográfica utilizando as bases de dados eletrônicos como Scielo, PubMed, Google, Google acadêmico e Periódico Capes. Para a busca do referencial teórico, utilizou-se o descritor em português e inglês “moluscos” combinante com os descritores “classes,“origem” e “filogenia”, utilizando o operador booleano AND. Foram selecionados para leitura 60 trabalhos (artigos e capítulos de livros) no período de dezembro de 2020 a março de 2021. Não foram considerados artigos relacionados a coleções zoológicas, sendo preferidos aqueles artigos que apresentavam características gerais do grupo em pauta. RESULTADOS: O Filo Mollusca está distribuído em oito classes, Solenogastres ou Neomeniomorpha; Caudofoveata ou Chaetodermomorpha; Polyplacophora; Bivalvia, Monoplacophora; Scaphopoda; Gastropoda e Cephalopoda. CONCLUSÃO: Em síntese, ficou evidenciado uma expressiva escassez de trabalhos em várias áreas, como biologia; história de vida; hábitos alimentares; morfologia; biogeografia; sistemática e filogenia; genética e em outras diversas áreas da zoologia. Apesar da elevada e significativa importância como fragmentadores nos ecossistemas, exercendo a ciclagem dos nutrientes e sustentando os níveis de produção primária e secundária conhecidos, são ainda negligenciados. Esse fato pode ter relação com as limitações e dificuldades da amostragem, identificação e manutenção de equipe técnica com elevado custo. Além disso, alguns grupos ocorrem somente em águas profundas e existem poucas linhas de pesquisa nas instituições acadêmicas.

Microfouling, ie biofilm formation on surfaces, can have an economic impact and requires costly maintenance in water-powered energy generation systems. In this study, the microbiota of a cooling system (filter and heat exchanger) in the Irape hydroelectric power plant in Brazil was examined. The goal was to identify bacteria that could be targeted to more efficiently reduce biofilm formation. Two sampling campaigns were made corresponding to two well-defined seasons of the Brazilian Cerrado biome: the dry (campaign 1) and the wet (campaign 2). Microfouling communities varied considerably over time in samples obtained at different times after the last clearance of the heat exchanger. The thermophilic bacteria Meiothermus, Thermomonas and Symbiobacterium were exclusive and abundant in the microfouling of the heat exchanger in campaign 2, while methanotrophs and iron-reducing bacteria were abundant only in filter sediments. These findings could help to guide strategies for ecofriendly measures to reduce biofilm fouling in hydroelectric power plants, minimizing environmental and economic losses.

Brain artery velocities (Time-Averaged Maximum Mean Velocity, TAMMV) by Transcranial Doppler (TCD), hematocrit, hemoglobin, Red blood cell (RBC) Distribution Width (RDW) and RBC rigidity index (Ri), when reported together with their correlations, provide a accurate and useful diagnostic picture than blood viscosity measurements alone. Additionally, our study included a sixth parameter provided by TCD, the Gosling Pulsatility Index PI, which is an indicator of CBF (Cerebral Blood Flow) resistance. All these parameters are routine in Hematology except for values of Ri. The rigidity (Ri) of the RBC is the main rheological characteristic of the blood of Sickle Cell Anemia (SCA) patients and several pathologies. However, its quantification depends on many commercial and experimental techniques, none disseminated and predominant around the World. The difference in absorbance values of the blood, during the process of sedimentation in a microwell of a Microplate Reader, is a straightforward way of semi-quantifying the RBC rigidity Ri, since the fraction of irreversibly sickled red blood cells does not form rouleaux. Erythrocyte Rigidity Index (Ri) was calculated using initial absorbance Ainitial (6 s) and final Afinal (540 s), Ri = 1 / (Ai-Af). The Ri of 119 patients (2–17 y / o, M & F) SCA, SCC (Sickle Cell/hemoglobin C), SCD (Sickle Cell/hemoglobin D), Sβ0thal (Sickle Cell/hemoglobin Beta Zero Thalassemia) and 71 blood donors (20–65 y / o, M & F) were measured in our laboratory while the five parameters (TAMMV and PI by TCD, Hct, Hb and RDW) were obtained from medical records. The in vitro addition of hydroxyurea (HU, 50mg /dl, n = 51 patients, and n = 8 healthy donors) in the samples decreased the rouleaux adhesion strength of both donor and patients’ blood samples, leading to extraordinarily high Ri values. The correlation between the studied parameters was especially significant for the direct relationships between Ri, TAMMV, and PI.

In South America, the presence of the non-native mollusc Limnoperna fortunei ( Dunker, 1857 ) (Mollusca, Bivalvia, Mytilidae) in rivers and reservoirs may result in several impacts on the environment and economic activities. In a continental scale, the factors that most influence the dispersion of the species are anthropogenic vectors such as the movement of boats and people. Due to this, distribution models based solely on climatic variables often fail to predict the areas most subject to invasion, both spatially and temporally. An alternative to overcome this problem is the evaluation assuming the phenomenon as a complex system. In this paper, we have used a cellular automata model to predict the spread of the golden mussel in the Brazilian territory, on a temporal and spatial scale. We assume three parameters of interest: a) altitude b) characteristics of the river, and c) human population density. Transition rules were defined based on various considerations discussed in the article. The algorithm estimated satisfactorily the risk of invasion by L. fortunei to date (year of 2016), and the simulations for the years 2030 and 2050 predicted a high risk of invasion in north and northeastern Brazil. The increased risk of invasion predicted by the model for the next decades indicates that prevention and control measures should be applied immediately and this is of the utmost importance for the country to be able to comply with the #9 Aichi target.

The golden mussel (Limnoperna fortunei) and Corbicula fluminea are considered well-established invasive species in the rivers of Brazil and South America. In addition to the environmental problems resulting from this invasion process, the economic issue, especially in hydroelectric dams, is very worrisome and has mobilized several types of studies on these invasive bivalves. The detection and identification of these organisms in their adult phase in the rivers is not a problem; however, the identification of bivalve larvae by usual morphological methods is difficult due to high similarity conserved in these stages. The use of PCR-RFLP has proven to be an efficient and agile molecular method that allowed the detection of different patterns in the agarose gel for the two bivalves tested. The gel pattern showed a 100 bp band for L. fortunei not detected for C. fluminea. Thus, it is possible to detect larvae of these species from water samples, which can be a powerful tool for environmental monitoring programs on aquatic invasive species.

Mutant hemoglobins thermodynamic phase transitions (HbS, HbC, etc.) have been the causes of serious hemoglobinopathies that have been affecting mankind since the dawn of human race. HbS polymerization is the best known of these transitions and the original cause of sickle cell anemia. Hydroxyurea (HU, NH2CONHOH) is widely used as the main drug administered for the treatment of Sickle Cell Anemia (SCA). Several hypotheses have been raised on the effects of HU on SCA. The most widespread and accepted one points to the production of fetal hemoglobin by the bone marrow, hindering the polymerization of deoxygen-ated HbS. Moreover, recent studies have reported that the short term in vivo effects of the HU have not been elucidated. By ordinary techniques of Materials Science (scanning electron microscopy, viscoelasticity, vis-cosity measurements, DSC and weight loss) we assessed the anti-nucleating, depolymerizing, and anti-gelling direct effects of HU on suspensions and type I bovine collagen gels. Scanning electron microscopy (SEM) revealed that the addition of HU results in the disappearance of the percolating three-dimensional network typical of collagen gels. Vane Rheometry tests pointed to a reduction in the yield stress (σ0) by add-ing HU into collagen gels with a concentration of 2.2 % w/v. In the liquid phase (sol), suspensions increased viscosity over time but decreased with the addition of HU, highlighting the depolymerizing effect of this substance. The weight loss of the sols is also affect by the addition of HU probably related to the lowering of the interactions between collagen/water as HU is added. The DSC essays indicated changes in the Cp curves as HU is added to the gel, decreasing the structural relaxations commonly observed in those gels. As a result, HU showed an effect on the phase transition of the studied gel, strengthening the hypothesis of anti-nucleating and anti-gelling action thereof on physical, reversible gels, and possibly on physical, reversible gels of mutant hemoglobin (HbS). Keywords: hydroxyurea, gelation, collagen, polymerization, sickle cell anemia.

Aragonite is a metastable polymorph of calcium carbonate found in mollusk’s shells, appearing in tiles and prismatic columns, cemented in a protein matrix - mainly proteins - that acts as a framework on which the aragonite is nucleated forming nacre, besides selecting the morphology of the nucleated cristaline phase. The presence of the mineralyzing organic matrix may affect osteoinductive properties of biogenic aragonite, hypothesis tested by combinated tests, comparing viability and bioactivity of biomineralizated aragonite and nacre. Bioactivity was observed by deposition of Ca-P (presumably calcium phosphate) on the surface of samples immersed in Simulated Body Fluid; biocompatibility was verified by adhesion with VERO cells; cytotoxicity and alkaline phosphatase activity assays were performed with human adipose stem cells (hASC). Samples were characterized by scanning electron microscopy and X-ray diffraction. Both materials showed similar behaviour on bioactivity assay; in contrast, exhibited different behaviours in the presence of hASC.

Predictive modelling of species’ distributions is an important tool in biogeography, evolution, ecology, conservation, and invasive-species management. In this study we applied four different algorithms: Mahalanobis Distance, Domain, GARP and MAXENT, using them to predict the potential distribution of Limnoperna fortunei, a freshwater mussel native to Southeast Asia and a major fouling pest of water supply systems in Hong Kong, Japan, and South America. For model input, we compiled native and invaded occurrence data from Asia (71 points) and South America (248 points) from the literature and BIOCLIM’s environmental layers related to air temperature and precipitation. To evaluate model quality we used different “training” and “test” data sets. On the Mahalanobis Distance and Domain algorithms, three sets of training data were used: 1) Asia points; 2) South America points; 3) Asia and South America points. For MAXENT the combinations were: 1) South America points (25% test data/75% training data); 2) Asia points (25% test data/75% training data); 3) South America training data/Asia test data; 4) Asia training data/ South America test data; 5) Asia + South America points (25% test data/75% training data). Comparing the responses of the four types of algorithms used, it was found that MAXENT was the most conservative model (i.e. it produced a smaller area of suitable habitats) followed in order by GARP, Domain and Mahalanobis Distance, which proved to be the widest. In general, the best results corresponded to models in which the points of occurrence covered a greater environmental variability (Asia+South America 25% test data/75% training data). They showed better performance for predicting correctly the occurrence of regions already known to host the species. An ensemble map was produced based on the best scenarios for each algorithm. This tool performed well in assessing the potential global distribution of L. fortunei even though it was generated from climatic macro variables without the use of locale-specific abiotic variables, which are more difficult to obtain.

Applying the theories of Materials Science and Engineering to describe the composition and hierarchy of microstructures that comprise biological systems could help the search for new materials and results in a deeper insight into evolutionary processes. The layered microstructure that makes up the freshwater bivalve Limnoperna fortunei shell, an invasive specie in Brazil, was investigated utilizing SEM and AFM for the determination of the morphology and organization of the layers; and XRD was used to determine the crystalline phases of the calcium carbonate (CaCO3) present in the shell. The presence of the polymorphs calcite and aragonite were confirmed and the calcite is present only on the external side of the shell. The shell of L. fortunei is composed of two layers of aragonite with distinct microstructures (the aragonite prismatic layer and the aragonite sheet nacreous layer) and the periostracum (a protein layer that covers and protects the ceramic part of the shell). A new morphology of the calcite layer was found, below the periostracum, without defined form, albeit crystalline.

Published studies that deal with the question of how the temperature of chair seats influences human activities are few, but the studies considering such a factor, a function of the type of material, could contribute to improvements in the design of chairs. This study evaluates seat temperatures of 8 types of chairs made of different materials. The parts of the furniture that people come into contact with, and the thermal response of the material to heating and cooling have been evaluated. Infrared thermography was used for this, as it is a non-contact technique that does not present any type of risk in the measurement of temperatures. Seats made of synthetic leather (leatherette), wood and polyester fabric were found to have the highest temperatures, and the plywood seat showed the lowest. The study has also revealed that thermography can contribute to studies of thermal comfort of chair seats in addition to determining the most suitable material.

The objective of the present study was to develop and characterize a support for the immobilization of Psilocybe castanella in order to optimize the process of incorporation of fungal inoculum into the soil. The ceramic supports were fabricated from slate powder in the shape of hollow spheres by the slip casting technique (suspension: 40% v/v). The sintering temperature was evaluated in the range of 850–1,070°C and porosity was analyzed by mercury intrusion. The temperature of 1,050°C was the most adequate for sintering of the ceramic supports, with the porosity obtained being less than 1%. The fungus was immobilized on the ceramic supports containing lignocellulosic substrate using disks of fungal mycelium grown on 2% malt agar as the inoculum. Fungal biomass was estimated by the quantification of ergosterol. Peroxidase and laccase activities were determined by the oxidation of ABTS in the presence and absence of H2O2, respectively. The efficiency of the immobilized inoculum was tested in a grinder containing coarse sand for 45 min at 75 rpm. The supports were colonized with P. castanella and enzymatic activities were detected after the fifth day of fungal growth. Immobilization of the fungus on the ceramic support provided 80% protection of the inoculum against loss of efficiency during mixture with soil. The results demonstrate the potential of the ceramic supports produced with slate powder for immobilization of basidiomycetous fungi and for application to soil bioremediation processes.

Our hypothesis is that the action of aggregating and disaggregating substances in the blood can be detected and quantified by the Microplate Reader. To ascertain the validity of this hypothesis, we selected two types of blood: one that naturally presents erythrocyte aggregation (pig blood) and the other that does not present aggregation (bovine blood). One important reason for the choice of pig blood is that its erythrocyte aggregation resembles that of human blood. T. infestans saliva was added to the pig blood as a disaggregating substance, while bovine fibrinogen was added to the bovine blood as a substance that promotes erythrocyte aggregation. We investigated the dynamic viscosity (h) of these mammals' blood, of T. infestans saliva and of the absorption (A) by Microplate Reader, carrying out UV-Vis spectrophotometric assays of pig plasma with different concentrations of triatominae saliva and of bovine blood with different concentrations of fibrinogen. Our findings indicate that spectroscopic techniques such as the Microplate Reader complement and expand the study of blood rheology, erythrocyte sedimentation and aggregation.

A presença de algumas macromoléculas no sangue esta associada a fenômenos de hiperviscosidade sangüínea e hiperagregação eritrocitária, quadro freqüente em algumas patologias (Diabetes, Hipertensão Arterial,etc). Este estudo investiga a agregação eritrocitária e sedimentação em amostras de sangue suíno, humano e bovino utilizando duas técnicas experimentais. O sangue humano e o de suínos agregam naturalmente formando roleaux enquanto o sangue bovino não agrega. A microestrutura foi investigada por microscopia óptica em amostras de sangue bovino (hematócrito 40%), suíno (hematócrito 1%, 5%, 10%, 30% e 40%) e humano (hematócrito 40%) e amostras de sangue bovino (hematócrito 40%) com adição de fibrinogênio nas concentrações de 5g/l, 10g/l, 20g/l, 25g/l e 30g/l. Os ensaios no Leitor de Microplacas foram realizados para se determinar o comportamento da agregação eritrocitária e sedimentação do sangue em função do hematócrito com e sem adição de fibrinogênio (para o sangue bovino). A microscopia óptica de luz transmitida permite a caracterização das microestruturas do sangue sob diferentes condições experimentais. Com o Leitor de Microplacas é possível distinguir-se três regiões no processo: a- Região I onde ocorre a agregação eritrocitária; b-Região II onde ocorre à predominância da etapa de sedimentação dos eritrócitos; e c- Região III onde ocorre um aumento lento da absorbância ocasionado também pela sedimentação dos eritrócitos. Associando a microscopia óptica com o Leitor de Microplacas é possível criar parâmetros para quantificar o processo de agregação e sedimentação do sangue, ferramentas úteis no diagnóstico e evolução de patologias que afligem tanto seres humanos como animais. The presence of some macromolecules in the blood is associated with blood hiperviscosity and hyperaggregation. We have studied erythrocyte aggregation and blood sedimentation on samples of swine, human and bovine blood. Bovine blood does not present erythrocyte aggregation while human and swine blood naturally aggregates at low shear rates and at stasis. The action of different bovine fibrinogen concentrations on the microstructure of bovine blood was analyzed and compared with swine and human blood. The phenomena were investigated using optical microscopy (to analyze blood microstructures) and Microplate Reader to measure absorbance (at a fixed wavelength, l=655nm) versus time(s). Experiments were performed using samples of bovine blood (hematocrit 40%), swine blood (H= 1%, 5%, 10%, 30% and 40%) and human blood (H= 40%); and samples of bovine blood (H= 40%) with the addition of bovine fibrinogen at different concentrations (5g/l, 10g/l, 20g/l, 25g/l and 30g/l). Using the Microplate Reader it was possible to distinguish three regions in the process: a-The region I where the erythrocyte aggregation occurs; b-region II where the sedimentation process is predominant and c-Region III where a very slow increase indicates that the persistence of sedimentation process. The association of the optical microscopy with the Microplate Reader technique makes possible the determination of quantitative parameters for the process of aggregation and sedimentation. These parameters will facilitate the diagnosis and a more accurate analysis of the evolution of pathologies that afflict both humans as animals.

A agregação eritrocitária excessiva está intimamente ligada à ocorrência de alguns processos patológicos e diretamente relacionada ao fenômeno de sedimentação eritrocitária. Neste trabalho investigamos as características cinéticas do processo de agregação e sedimentação eritrocitária. Para este estudo foram realizados ensaios de VHS (Velocidade de Hemossedimentação) com sangue suíno (hematócrito H de 20%, 25%, 30% e 35%) e absorbância em função do tempo, utilizando espectrofotometria UV-Vis, em amostras de sangue suíno (hematócrito de 1%, 5%, 10%, 15%, 20% e 30%) e sangue humano (hematócrito de 5%, 10%, 15% e 20%). Os ensaios de VHS indicaram que a sedimentação diminui com o aumento do hematócrito (H); entretanto, nos ensaios de espectrofotometria o fenômeno não é observado. O VHS é uma técnica essencialmente macroscópica enquanto a espectrofotometria fornece informações que facilitam uma análise da microestrutura do sangue e a compreensão das etapas dos processos de agregação e sedimentação. É possível distinguir, com o UV-Vis, quatro regiões no processo: a- Região I onde ocorre a agregação eritrocitária; b- Região II onde ocorre crescimento dos agregados e termina o início da sedimentação; c- Região III onde ocorre a sedimentação da amostra; e d- Região IV, um platô que indica a parte final do processo de sedimentação. Erythrocyte aggregation is at the root of many pathological processes and directly related to the phenomenon of erythrocyte sedimentation. Here we have investigated the kinetic characteristics of the erythrocyte aggregation and erythrocyte sedimentation of swine blood samples using the ESR (Erythrocyte Sedimentation Rate) technique and the UV-Vis spectrophotometer (absorbance) at a fixed wavelength (655 nm) versus time(seconds) of swine and human blood samples. For the ESR experiments of swine blood we have used samples with different hematocrits H= 20%, 25%, 30% e 35%. For the UV-Vis experiments of swine blood samples we have used the hematocrits H= 1%. 5%, 10%, 15% and 20% at a fixed 655 nm wavelength and for the human blood the hematocrits chosen were H=5%, 10%, 15% and 20%. Blood sedimentation rate data has been measured at 300s intervals during a period of 10,000s. While the UV-Vis assays had been carried through during 1.200s with data acquisition every 1s. ESR results show that the sedimentation rate of swine blood decreases as the hematocrit increases while the reverse phenomenon occurs in the UV-Vis experiments. From the ESR it is possible to distinguish three regions: I-the red blood cell aggregation process which is a plateau; II- the sedimentation process and III- a plateau indicating the end of sedimentation. With the UV-Vis it is possible to observe the sedimentation in much more detail with at least four regions: I-the aggregation slope; II-The aggregation and growth of roleaux followed by an "avalanche" of erythrocyte sedimentation; III-the sedimentation; IV- end of sedimentation.

The glass transition temperature ( T g ) of sugar-related glasses is close to room temperature and here we report the affect of water concentration on the T g of caramel–water mixtures. Based on viscosity measurements, thermal analysis and X-ray diffraction (XRD) experiments we have investigated the occurrence of the T g during differential scanning calorimetry (DSC) runs on cooling (down to ∼170 K) and heating cycles of the caramel glasses and caramel–water mixtures. The caramel–water mixtures are viscous melts with Newtonian rheology. Their melts bear a resemblance to a silicate melt which do not deviate from Vogel–Fulcher–Tammann (VFT) equation fit as the glass approaches T g . The DSC measurements did detect low temperature transitions in caramel–water mixtures and the T g of the dried caramel glass sample. If crystallization is avoided on cooling to ∼170 K then a glass transition and devitrification of the mixture will occur on heating the sample from ∼170 K up to the ambient room temperature. The detectability of the glass transition depends on the cooling rate and water concentration.

In the past forty years considerable progress has been achieved on the knowledge of human blood as a non-Newtonian shear-thinning suspension, whose initial state, that is at rest (stasis) or at very low shear rates, has a gel-like internal structure which is destroyed as shear stress increases. The main goal of this communication is to describe the role of geometrical aspects during RBC (red blood cell) aggregate formation, growth and compaction on naturally aggregate (porcine blood) and non-aggregate (bovine blood) samples. We consider how these aspects coupled with tension equilibrium are decisive to transform red cell linear roleaux to three-dimensional aggregates or clusters. Geometrical aspects are also crucial on the compaction of red blood cell aggregates. These densely packed aggregates could precipitate out of blood- either as dangerous deposits on arterial walls, or as clots which travel in suspension until they block some crucial capillary.

In this study we characterized the surface morphology and ultrastructure of the foot of the golden mussel, Limnoperna fortunei (Dunker, 1857), relating its characteristics to the attaching mechanisms of this mollusk. The observation of the foot of this bivalve reveals the presence of micro-scaled cilia with a unique shape, which has a narrowing at its end. This characteristic was associated to the capacity for underwater adhesion to substrates through the employment of van der Waals forces, resembling the adhesion phenomenon of the gecko foot. The temporary attachment during locomotion by means of the foot to substrates was observed to be strong even on smooth surfaces, like glass, or hydrophobic waxy surfaces. Comparing TEM and light microscopy results it was possible to associate the mucous secretions and secreting cells found along the tissues to the production of the byssus inside the groove on the ventral portion of the foot. Not only our experiments, but also the state of the art allowed us to discard the involvement of secretions produced in the foot of the mussel to the temporary adhesion. Through SEM images it was possible to build a virtual three-dimensional model where total foot surface was measured for the estimated calculation of van der Waals forces. Also, some theoretical analysis and considerations have been made concerning the characteristics of the functional surface of L. fortunei foot.

Os tijolos refratários do sistema Al2O3-SiC-C foram introduzidos nos revestimentos para carros-torpedo na década de 80. A formação de trincas paralelas à face quente desses tijolos com posterior lascamento da porção afetada é o principal motivo da redução da vida útil desse revestimento. As modificações microestruturais nesses tijolos, combinadas com esforços de natureza mecânica e térmica, são apontadas como a causa mais freqüente da fratura desses refratários. Os resultados da caracterização realizada em amostras de tijolos refratários novos, cuja formulação comercial foi intencionalmente modificada, indicaram que o tipo de resina fenólica, utilizado como ligante das partículas cerâmicas dos refratários para carro-torpedo, exerce efeitos significativos nas propriedades desses tijolos. Al2O3-SiC-C bricks have been widely used for torpedo cars since the 80's. Crack formation parallel to the hot face of the Al2O3-SiC-C bricks followed by the spalling of the affected portion has been the main reason for the premature wear of the refractories. Microstructure changes, combined with mechanical and thermal stresses, have been pointed out as the cause for the fracture of these materials. The current results of laboratory tests used for characterizing four Al2O3-SiC-C bricks indicated, for the evaluated conditions, that the kind of resin has significant effect on the properties of Al2O3-SiC-C bricks.

Cortical bone porosity of bovine tibia samples has been investigated using the mercury intrusion porosimetry (MIP) technique. Cortical bone porosity range from 10 nm (caniculae) to 40 mm (Harvers canals), well in the measuring range region for the MIP technique. Samples from fresh bovine cortical bone were treated, dried and cut into ~ (3x1x1) cm pieces .The aim of the work was twofold: 1- To investigate bone porosity structure and direction quantitatively; 2- To obtain tri-dimensional scientific visualization (SV) images of cortical bone porosity. The MIP experiments associated with SV seem to be a good tool for studies of bone loss mechanisms, bone porosity distribution and bone growth phenomena.