3D Printing characteristics and mechanical properties of a bio scaffold obtained from a Micro-CT Scan, using the fused deposition modeling technique

The objective is to determine which biopolymer has the best 3D printing characteristics and mechanical properties for the manufacture of a bioscaffold, using the fused deposition printing technique, with models generated from an STL file obtained from a Micro-CT scan taken from a bovine iliac crest bone structure. Through an experimental exploratory study, three study groups of the analyzed biopolymers were carried out with thirteen printed structures of each one. The first is made of 100% PLA. The second, 90B, we added 1g of diatom extract, and the third, 88C, differs from the previous one in that it also contains 1g of calcium phosphate. The 39 printed structures underwent a visual inspection test, which required the fabrication of a gold standard scaffold in resin, with greater detail and similarity to the scanned bone structure. Finally, the structures were subjected to a compressive force (N) to obtain the modulus of elasticity (MPa) and compressive strength (MPa) of each one of them. A statistically significant difference (p=0.001) was obtained in the printing properties of the biomaterial 88C, compared to 90B and pure PLA and the 88C presented the best 3D printing characteristics. In addition, it also presented the best mechanical properties compared to the other groups of materials. Although the difference between these was not statistically significant (p=0.388), in the structures of the 88C biomaterial, values of compressive strength (8,84692 MPa) and modulus of elasticity (43,23615 MPa) were similar to those of cancellous bone in the jaws could be observed. Because of this result, the 88C biomaterial has the potential to be used in the manufacture of bioscaffolds in tissue engineering.

El objetivo es determinar cuál biopolímero presenta las mejores características de impresión 3D y propiedades mecánicas para la fabricación de un bioandamiaje, utilizando la técnica de impresión por deposición fundida, con modelos generados a partir de un archivo en formato STL que se obtuvo de un Micro-CT Scan de una estructura osea de cresta iliaca bovina. Mediante un estudio exploratorio, se realizaron 3 grupos de estudio con trece estructuras impresas de cada uno. El primero, se compone 100% de PLA. El segundo, 90B, se le agrega 1g de extracto de diatomea, y el tercero, 88C, se diferencia del anterior ya que contiene además, 1g de fosfato de calcio. A las 39 estructuras impresas se les realizó una prueba de inspección visual, por lo que se requirió la confección de un patrón de oro en resina, con mayor detalle y similitud a la estructura ósea escaneada. Finalmente, las estructuras fueron sometidas a una fuerza compresiva (N) para la obtención del módulo de elasticidad (MPa) y de la resistencia compresiva (MPa) de cada una de ellas. Se obtuvo una diferencia estadísticamente significativa (p=0,001) en las propiedades de impresión del biomaterial 88C, con respecto al 90B y al PLA puro, presentando las mejores características de impresión 3D. Además, obtuvo las mejores propiedades mecánicas en comparación con los otros grupos de materiales. Aunque la diferencia entre estos no fue estadísticamente significativa (p=0,388), en las estructuras del biomaterial 88C, se pudieron observar valores de resistencia compresiva (8,84692 MPa) y módulo de elasticidad (43,23615 MPa) que son semejantes a los del hueso esponjoso de los maxilares. A razón de este resultado, el biomaterial 88C cuenta con el potencial para ser utilizado en la fabricación de bioandamiajes en la ingeniería tisular.

Enzymatic Digestion Method Coupled with Artificial Intelligence Techniques in Forensic Drowning Diatom Detection / 中山大学学报(医学科学版)

ObjectiveArtificial intelligence （AI） full smear automated diatom detection technology can perform forensic pathology drowning diatom detection more quickly and efficiently than human experts.However， this technique was only used in conjunction with the strong acid digestion method， which has a low extraction rate of diatoms. In this study， we propose to use the more efficient proteinase K tissue digestion method （hereinafter referred to as enzyme digestion method） as a diatom extraction method to investigate the generalization ability and feasibility of this technique in other diatom extraction methods. MethodsLung tissues from 6 drowned cadavers were collected for proteinase K ablation and made into smears， and the smears were digitized using the digital image matrix cutting method and a diatom and background database was established accordingly.The data set was divided into training set， validation set and test set in the ratio of 3：1：1， and the convolutional neural network （CNN） models were trained， internally validated， and externally tested on the basis of ImageNet pre-training. ResultsThe results showed that the accuracy rate of the external test of the best model was 97.65 %， and the area where the model features were extracted was the area where the diatoms were located. The best CNN model in practice had a precision of more than 80 % for diatom detection of drowned corpses. ConclusionIt is shown that the AI automated diatom detection technique based on CNN model and enzymatic digestion method in combination can efficiently identify diatoms and can be used as an auxiliary method for diatom detection in drowning identification.

Application Progress of High-Throughput Sequencing Technology in Forensic Diatom Detection / 法医学杂志

Diatom detection is an important method for identifying drowning and throwing corpses after death and inferring the drowning sites in forensic examination of corpses in water. In recent years,high-throughput sequencing technology has achieved rapid development and has been widely used in research related to diatom taxonomic investigations. This paper reviews the research status and prospects of high-throughput sequencing technology and its application in forensic diatom detection.

Eunotia (Bacillariophyceae) from a subtropical stream adjacent to Iguaçu National Park, Brazil, with the proposition of a new species / Eunotia (Bacillariophyceae) de um riacho subtropical adjacente ao Parque Nacional do Iguaçu, Brasil, com a proposta de uma espécie nova

Abstract: Eunotia species from a stream located in the surrounding area of the Iguaçu National Park conservation unit were analyzed. Samples were monthly collected from September 2012 to August 2013. The periphytic material, manually obtained by squeezing aquatic macrophytes, was oxidized and analyzed under light and scanning electron microscopy. Twenty-one infrageneric taxa of Eunotia were identified, measured, and illustrated. Eunotia caniculoides sp. nov. is proposed as a new species, and eight taxa are new records for Paraná state.

Resumo: Espécies de Eunotia Ehrenberg de um ambiente lótico localizado em área adjacente à unidade de conservação Parque Nacional do Iguaçu foram analisadas. As coletas foram realizadas mensalmente de setembro de 2012 a agosto de 2013. O material perifítico obtido do espremido manual de macrófitas aquáticas foi oxidado e analisado sob microscopia óptica e eletrônica de varredura. Vinte e um táxons de Eunotia foram identificados, medidos e ilustrados. Eunotia caniculoides sp. nov. é proposta como uma nova espécie e oito táxons constituem novos registros para o estado do Paraná.

Application of Artificial Intelligence Automatic Diatom Identification System in Practical Cases / 法医学杂志

Objective To discuss the application of artificial intelligence automatic diatom identification system in practical cases, to provide reference for quantitative diatom analysis using the system and to validate the deep learning model incorporated into the system. Methods Organs from 10 corpses in water were collected and digested with diatom nitric acid; then the smears were digitally scanned using a digital slide scanner and the diatoms were tested qualitatively and quantitatively by artificial intelligence automatic diatom identification system. Results The area under the curve （AUC） of the receiver operator characteristic （ROC） curve of the deep learning model incorporated into the artificial intelligence automatic diatom identification system, reached 98.22% and the precision of diatom identification reached 92.45%. Conclusion The artificial intelligence automatic diatom identification system is able to automatically identify diatoms, and can be used as an auxiliary tool in diatom testing in practical cases, to provide reference to drowning diagnosis.

The genus Tryblionella W. Smith (Bacillariaceae, Bacillariophyta) in southern Brazil salt marshes / O gênero Tryblionella W. Smith (Bacillariaceae, Bacillariophyta) em marismas do Sul do Brasil

Abstract: Tryblionella is a large epipelic genus, widespread from fresh to marine waters. Most of the studies including the genus are based only in light microscopy. Few recent studies are exclusively dedicated to Tryblionella and the ultrastructure of some species is still little known. In this paper we present eleven species of Tryblionella found in epiphyton and microphytobenthos in Patos Lagoon salt marshes. All the species are described, illustrated in light and scanning electron microscopy and comments about their taxonomy, distribution and ecology are provided. Two taxa are reported for the first time in the State of Rio Grande do Sul and one in Southern Brazil. The number of species registered in this study comprises nearly a half of the number of species registered in the country. The high richness observed may be related to the dynamics of the salt marshes, which provides both the mixing of fresh and marine waters communities and the diversity of microhabitats. The great variability among the species analyzed allowed to extend the general concept of Tryblionella, adding features which were not considered in the previous characterizations of the genus.

Resumo: Tryblionella é um gênero de diatomáceas epipélicas, distribuído de águas doces a marinhas. A maioria dos estudos que incluem o gênero baseia-se apenas em microscopia óptica. Poucos estudos recentes são exclusivamente dedicados à Tryblionella e a ultraestrutura de algumas espécies ainda é pouco conhecida. No presente artigo, apresentamos onze espécies de Tryblionella encontradas no epifíton e no microfitobentos nas marismas da Lagoa dos Patos. Todas as espécies foram descritas, ilustradas em microscopia óptica e eletrônica de varredura e comentários sobre a taxonomia, distribuição e ecologia foram fornecidos. Dois táxons foram registrados pela primeira vez para o estado do Rio Grande do Sul e um para a região Sul do Brasil. O número de espécies registradas neste estudo compreende cerca de metade das espécies registradas para o país. A grande riqueza observada pode estar relacionada à dinâmica das marismas, que proporciona tanto a mistura de comunidades de águas doces e marinhas quanto diversidade de microhabitats. A grande variabilidade entre as espécies analisadas permitiu que o conceito geral de Tryblionella fosse ampliado, incluindo características que não haviam sido consideradas nas caracterizações anteriores do gênero.

Protists and other organisms on a minute snail periostracum / Protistas e outros organismos em um pequeno periostracum de caracol

Abstract Since the foundation of the Malacological Center in 1980, Universidad Centro Americana (UCA), Managua-Nicaragua, has been monitoring and collecting the marine, terrestrial, fluvial and lake mollusk population of the country. Many specimens have been photographed by Scanning Electronic Microscope (SEM), and in one of these, observation of the hairy periostracum reveals a seemingly thriving population of minute protists in possible symbiosis with their host. Adequate magnification and comparison with previous studies allowed the determination of these hosts as diatoms, testaceous amoebae, yeast, phacus, spores and other undetermined organisms which occur in tropical forests on rocks, trees and leaves. Here illustrated are diatoms and other organisms detected for the first time on the periostracum of a tropical rainforest mollusk.

Resumo Desde a fundação do Centro Malacológico em 1980, a Universidad Central Americana (UCA), Manágua-Nicarágua, vem acompanhando e coletando a população de moluscos marinhos, terrestres, fluviais e lagoas do país. Muitos espécimes foram fotografados pelo microscópio eletrônico de varredura (SEM) e, em um deles, a observação do periostracum peludo revela uma população aparentemente próspera de protistas de minuto em possível simbiose com o hospedeiro. A ampliação adequada e a comparação com estudos anteriores permitem a determinação dessas diatomáceas, amebas testaceas, leveduras, phacus, esporos e outros organismos indeterminados que ocorrem em florestas tropicais em rochas, árvores e folhas. Aqui estão as diatomeas e outros organismos pela primeira vez detectados no periostracum de um molusco tropical.

Ácidos grasos en cepas de microalgas del Banco de Germoplasma de Organismos Acuáticos del Instituto del Mar del Perú (IMARPE)

Se determinó la composición de ácidos grasos de 54 cepas microalgales colectadas del Perú y mantenidas en el Banco de Germoplasma de Organismos Acuáticos (IMARPE) con la finalidad de determinar su uso nutricional en la acuicultura. Para ello se realizaron cultivos en un volumen de 50 mL y se determinaron los porcentajes relativos de ácidos grasos mediante transesterificación directa y cromatografía de gases. En el grupo Chlorophyta las microalgas que presentaron los mayores valores de porcentaje relativo de ácidos grasos fueron Chlamydomonas reinhardtii (16:0; 41.2%), Scenedesmus obtusus (18:1n-7; 33.6%), Acutodesmus dimorphus (18:1n-9; 37.1%), Desmodesmus armatus (18:3n-3; 32.2%) y Tetraselmis contracta (16:4n-3; 16.5%). En cambio en el grupo Bacillariophyta, los ácidos grasos más abundantes fueron 16:1n-7 en Chaetoceros didymus (20.2%), 18:4n-3 en Navicula sp. (28.3%) y EPA en Asterionellopsis sp. (31.5%). Por otro lado, en el grupo Dinophyta, todas las cepas superaron el 20% de DHA, en particular, la cepa de Akashiwo sanguinea presentó el mayor porcentaje relativo de este ácido graso (29.9%) y de los ácidos grasos 16:0 (24.8%) y EPA (16%). Se discute el uso de estas cepas según su contenido de ácidos grasos.

In This work, we determinate the fatty acids composition and their nutritional value in 54 microalgal strains, collected from Peru and stored in Banco de Germoplasma de Organismos Acuáticos (IMARPE). The cultures were grown to 50 mL and analyzed by direct transesterification and gas chromatography. In the Chlorophyta group, the microalgaes that present the highest relative percentage of fatty acids were Chlamydomonas reinhardtii (16:0; 41.2%), Scenedesmus obtusus (18:1n-7; 33.6%), Acutodesmus dimorphus (18:1n-9; 37.1%), Desmodesmus armatus (18:3n-3; 32.2%) and Tetraselmis contracta (16:4n-3; 16.5%). Moreover in the Bacillariophyta group, the most abundant fatty acids were 16:1n-7 in Chaetoceros didymus (20.2%), 18:4n-3 in Navicula sp. (28.3%) and EPA in Asterionellopsis sp. (31.5%). By the other hand, in the Dinophyta group, all strains exceed the 20% of DHA, in particular Akashiwo sanguinea, it was strain to have the highest percentage of this fatty acid (29.9%) in addition to 16: 0 (24.8%) and EPA (16%). We discussed uses of these strains is according to their fatty acids content.

Microbialite-like structures in Cladophora sp. (Ulvophyceae) mats from a subtropical Andean basin: ecological implications / Estructuras de tipo microbialito en Cladophora sp. (Ulvophyceae) de una cuenca andina subtropical: implicaciones ecológicas

Abstract The solubility equilibrium of calcite is influenced by physicochemical, climatic and biological factors. Annual cycles of exceptionally prolonged drought, in conjunction with naturally occurring diffuse organic pollution, generate the unique conditions for the precipitation of lithified carbonate structures (microbialites). The aim of this article is to analyze the possible implications of calcite precipitation produced in mats of Cladophora sp. in an Andean subtropical basin, considering it is the first time this phenomenon is described for the region. We collected samples from selected sites at the Lules River Basin, in four sampling dates between the years 2003 and 2004, within a monitoring work of 15 years. Samples were analyzed using an electron microscope and X-ray diffraction analysis. We found that Gomphonema sp. attached to Cladophora sp. contributes to precipitation of calcite and formation of microbialite like structures, in the studied area. This work presents an initial discussion of the discovery of microbialites-like structures attached to Cladophora sp. mats in a subtropical Andean stream and the environmental conditions that lead to their production, as well as the possible ecological implications of these microbialites.(AU)

Resumen La fase sólida de las sales de los cuerpos de agua juega un papel importante en la concentración de los elementos mayoritarios. El equilibrio de solubilidad de la calcita está influenciado por factores fisicoquímicos, climáticos y biológicos. Los ciclos anuales de sequía excepcionalmente prolongada, junto con la contaminación orgánica difusa de origen natural, generan condiciones únicas para la precipitación de estructuras de carbonato litificado (microbialitos). El objetivo de este artículo es analizar las posibles implicaciones de la precipitación de calcita producida en Cladophora sp. en una cuenca subtropical andina, considerando que es la primera vez que se describe este fenómeno para la región. Recolectamos muestras en sitios seleccionados en la Cuenca del Río Lules, en cuatro fechas de muestreo entre 2003 y 2004, en el marco de un trabajo de monitoreo de quince años. Usamos red Surber para realizar los muestreos. Las muestras de algas, una vez libres de macroinvertebrados, se secaron y pesaron. Analizamos utilizando microscopía electrónica y difracción de rayos X. Encontramos que Gomphonema sp. unido a Cladophora contribuye a la precipitación de calcita y la formación de estructuras similares a microbialitos, en el área estudiada. Este trabajo presenta una discusión inicial sobre el descubrimiento de estructuras similares a microbialitos unidas a filamentos de Cladophora sp. en una cuenca andina subtropical y las condiciones ambientales que conducen a su producción, así como las posibles implicaciones ecológicas de lo mencionado anteriormente.(AU)

Application of Quantitative Analysis of Diatoms in Lung Tissue for the Diagnosis of Drowning of Experimental Animals / 法医学杂志

Objective To discuss the application value of diatom examination in lung tissue for the forensic diagnosis of drowning. Methods The experimental animals were divided randomly into drowning, postmortem submergence and dying on land group. Diatoms in lung tissue and drowning fluid were analyzed quantitatively by microwave digestion-vacuum filtration-automated scanning electron microscopy diatom examination method. The ratios of content of diatoms in lung tissue and drowning fluid （CL/CD ratio） were recorded. Results The CL/CD ratios of experimental rabbits in the drowning group （5.82±3.50） were much higher than that of postmortem submergence group （0.47±0.35）; the CL/CD ratios of different parts of the lung lobes of experimental pigs in the drowning group were higher than that of postmortem submergence group （P<0.05）; in seawater, brackish water, river fresh water and lake fresh water, the CL/CD ratios of experimental pigs in the drowning group were higher than that of postmortem submergence group （P<0.05）. In animal experiments, all the cases with CL/CD ratio >1.6 were from drowning group. Conclusion CL/CD ratio is an indicator with good application prospects in the diagnosis of drowning.

Gomphonema Ehrenberg (Bacillariophyceae, Gomphonemataceae) of the São Francisco Falso River, Paraná, Brazil / Gomphonema Ehrenberg (Bacillariophyceae, Gomphonemataceae) do rio São Francisco Falso, Paraná, Brasil

Abstract: Gomphonema Ehrenberg is a genus well represented in periphytic algal flora of epicontinental environments. The substrate colonization is facilitated by the secretion of mucilage by the pore field, allowing cell adhesion. Samples were scraped off and analyzed from vegetative portions of the macrophyte Eichhornia azurea Kunth, collected in São Francisco Falso River, located in Santa Helena City, Paraná State. The sampling occurred in four different sites, in four different periods, totaling 16 samples. The quantitative material analysis resulted in 28 identified taxa, in which Gomphonema brasiliense ssp. pacificum, Gomphonema neoapiculatum Lange-Bertalot, Reichardt & Metzeltin Gomphonema pantropicum Reichardt and Gomphonema perapicatum Metzeltin & Lange-Bertalot represented pioneer citations for Paraná diatomflorula. The ultrastructure observations of some species were crucial to distinguish a few taxa, as Gomphonema brasiliense and Gomphonema brasiliensoide D. Metzeltin, Lange-Bertalot & F. García-Rodríguez. We suggest future studies in this environment, once it has propitious characteristics to the development of epilithic diatoms. Moreover, phylogenetic studies are also recommended for a better distinction of taxa with a wide morphologic variation.

Resumo: Gomphonema Ehrenberg é um gênero bem representado na flora algal perifítica de ambientes epicontinentais. A colonização de substratos é facilitada pela secreção de mucilagem pelo campo de poros permitindo a adesão das células. As amostras analisadas foram removidas das porções vegetativas da macrófita Eichhornia azurea Kunth, coletadas no rio São Francisco Falso, localizado no município de Santa Helena, Paraná. As coletas ocorreram em quatro estações de amostragem, em quatro períodos diferentes, totalizando 16 amostras. A análise qualitativa do material resultou na identificação de 28 táxons, sendo que Gomphonema brasiliense ssp. pacificum, Gomphonema neoapiculatum Lange-Bertalot, Reichardt & Metzeltin Gomphonema pantropicum Reichardt e Gomphonema perapicatum Metzeltin & Lange-Bertalot constituíram citações pioneiras para a diatomoflórula do Paraná. As observações da ultra-estrutura de algumas espécies foram decisivas para distinção entre alguns táxons, como por exemplo, Gomphonema brasiliense Grunow e Gomphonema brasiliensoide D. Metzeltin, Lange-Bertalot & F. García-Rodríguez. Sugerem-se futuros estudos desse ambiente, uma vez que o mesmo possui características propícias ao desenvolvimento de diatomáceas epilíticas, além de estudos filogenéticos para melhor distinção dos táxons com ampla variação morfológica.

Application of Specific Fragment Length Polymorphism of Algae rDNA in Identification of Drowning Cases / 法医学杂志

OBJECTIVES@#To identify the drop-off location of victims in drowning cases, and confirm whether it is a fatal drowning or the victim is thrown into the water after death by detecting part of 5.8S sequence and second internal transcribed spacer （ITS2） （5.8S+ITS2） of diatom rDNA in water and organs.@*METHODS@#Two cases identified by diatom examination, which received by Nanjing Municipal Public Security Bureau Forensic Center, were taken as the research objects. The difference of the population structure of algae in water and human tissue was analysed by length polymorphism of 5.8S+ITS2 marker.@*RESULTS@#In case 1, similar species of diatom were detected from victim's lung and liver tissues and the water sample. Two kinds of DNA fragments with length of 330 bp and 376 bp were detected from victim's lung tissue and the water sample using 5.8S+ITS2 marker, which could confirm the victim was drowning before death. In case 2, there was no diatom found in victim's lung and liver tissues. Only one kind of DNA fragment with length of 331 bp and low relative fluorescence unit （RFU） was obtained from victim's lung tissue using 5.8S+ITS2 marker, thus the victim was thrown into the water after death.@*CONCLUSIONS@#The experimental results of the two cases in present study are consistent with the actual facts and the result of the diatom microscopic examination. The difference of population structure of specific microorganism in water and human tissue can be detected by 5.8S+ITS2 marker, which can help to identify the drop-off location of victims in drowning cases, and confirm whether it is a fatal drowning or the victim is thrown into the water after death.

Research Progress on Determination of Drowning Site / 法医学杂志

The bodies found in water are one of the most common types in forensic practice. The dis-covery site of the body is often not the drowning site. However, the determination of drowning site is vital for the identification of victim. Inorganic particles and planktons, such as granular impurities, diatoms and bacteria, are valuable markers for the diagnosis of drowning. By comparing the granular impurities and planktons in tissues and suspicious drowning mediums, the drowning site can be concluded based on their similarity of types and distribution, which has practical applied value. In this paper, the research progress on determination of drowning site is summarized to provide reference for the peers.

Protists and other organisms on a minute snail periostracum

Abstract Since the foundation of the Malacological Center in 1980, Universidad Centro Americana (UCA), Managua-Nicaragua, has been monitoring and collecting the marine, terrestrial, fluvial and lake mollusk population of the country. Many specimens have been photographed by Scanning Electronic Microscope (SEM), and in one of these, observation of the hairy periostracum reveals a seemingly thriving population of minute protists in possible symbiosis with their host. Adequate magnification and comparison with previous studies allowed the determination of these hosts as diatoms, testaceous amoebae, yeast, phacus, spores and other undetermined organisms which occur in tropical forests on rocks, trees and leaves. Here illustrated are diatoms and other organisms detected for the first time on the periostracum of a tropical rainforest mollusk.

Resumo Desde a fundação do Centro Malacológico em 1980, a Universidad Central Americana (UCA), Manágua-Nicarágua, vem acompanhando e coletando a população de moluscos marinhos, terrestres, fluviais e lagoas do país. Muitos espécimes foram fotografados pelo microscópio eletrônico de varredura (SEM) e, em um deles, a observação do periostracum peludo revela uma população aparentemente próspera de protistas de minuto em possível simbiose com o hospedeiro. A ampliação adequada e a comparação com estudos anteriores permitem a determinação dessas diatomáceas, amebas testaceas, leveduras, phacus, esporos e outros organismos indeterminados que ocorrem em florestas tropicais em rochas, árvores e folhas. Aqui estão as diatomeas e outros organismos pela primeira vez detectados no periostracum de um molusco tropical.

Taxonomy, morphology and distribution of Cymatosiraceae (Bacillariophyceae) in the littorals of Santa Catarina and Rio Grande do Sul / Taxonomia, morfologia e distribuição de Cymatosiraceae (Bacillariophyceae) nos litorais de Santa Catarina e Rio Grande do Sul

Species of Cymatosiraceae (diatoms) studied from Santa Catarina and Rio Grande do Sul littorals: Campylosira cymbelliformis, Cymatosira belgica, Cymatosirella minutissima, Plagiogrammopsis minima and Plagiogrammopsis vanheurckii) are presented with a morphological description, dimension data, distribution in the studied area and are illustrated in light microscope, and scanning and transmission electron microscopes. Superficial sand samples from the swash zone and plankton were collected from over 30 marine sandy beaches. Cymatosirella minutissima and Plagiogrammopsis minima are new recordings in Brazil widening their distribution to South America, previously being restricted to Europe. Campylosira cymbelliformis was the species most often observed in plankton samples and Plagiogrammopsis minima in sediment samples. Cymatosira belgica and Plagiogrammopsis minima were recorded as abundant species in Mariscal, Quatro Ilhas and Zimbros reaching a relative frequency of 9.6%. The study adds new morphological data to some taxa as the presence of rimoportula on C. minutissima and one row of poroids on copulae of P. minima, these features being in agreement with Cymatosiraceae diagnosis.

As espécies de Cymatosiraceae (diatomácea) encontradas no litoral de Santa Catarina e Rio Grande do Sul: Cymatosira belgica, Campylosira cymbelliformis, Cymatosirella minutissima, Plagiogrammopsis minima e Plagiogrammopsis vanheurckii são apresentadas com descrições morfológicas acompanhadas de dados referentes a dimensões, distribuição na área de estudo e ilustrações em microscopia óptica, e eletrônica de varredura e de transmissão. As amostras da areia superficial foram coletadas na região de varrido das ondas e de plâncton em mais de 30 praias arenosas. Cymatosirella minutissima and Plagiogrammopsis minima são registros novos para o Brasil ampliando sua distribuição para a América do Sul antes restritas à Europe. Campylosira cymbelliformis foi a espécies mais frequentemente observada nas amostras de plâncton and Plagiogramma minima in the sediment samples. Cymatosira belgica e Plagiogrammopsis minima são registradas como espécies abundantes em Mariscal, Quatro Ilhas e Zimbros alcançando a freqüência relativa máxima de 9,6%. Este estudo adiciona novos dados morfológicos para alguns táxons com a presença de uma rimopórtula em C. minutissima e uma fileira de poróides nas cópulas de P. minima, estando estas características de acordo com a diagnose da Cymatosiraceae.

Tolerancia de diez especies de diatomeas (Bacillariophyceae) a los factores físico-químicos del agua en el Río Sarapiquí, Costa Rica / The tolerance of ten diatom species (Bacillariophyceae) to water's physico-chemical factors in the Sarapiqui River, Costa Rica

ResumenLas diatomeas del bentos son el componente más estudiado del perifiton en los ríos de Costa Rica, sin embargo aún queda mucho por conocer sobre su ecología. Por eso en el presente estudio se analizó el perifiton en seis diferentes sitios en la cuenca medio del Río Sarapiquí en el 2010, 2011 y 2012. En cada uno de los muestreos se realizó el conteo de 400 frústulas, de las cuales se obtuvo la abundancia relativa de las especies: Achnanthidium exiguum, Coconneis placentula, Cymbella tumida, Luticola goeppertiana, Luticola ventricosa, Navicula symmetrica, Nitzchia clausii, Nupela praecipua, Reimeria sinuata y Synedra goulardi. Esta información fue relacionada con los datos físico químicos (oxígeno disuelto, temperatura, conductividad, total de sedimentos en suspensión, turbidez, pH y alcalinidad) medidos en cada uno de los sitios. Con el propósito de observar las relaciones entre los diferentes sitios dentro de la cuenca, se utilizó un análisis de correspondencia canónica (ACC), lo que permitió distinguir tres sectores de acuerdo a la altitud. Estos sectores se diferencian en el tipo de sustrato, cobertura riparia vegetal y parámetros físico-químicos, lo que propicia diferencias en la composición de especies de diatomeas entre ellos. Se obtuvieron los valores óptimos calculados y tolerancia calculada para cada una de las especies. Los resultados obtenidos indican que las especies: A. exiguum, R. sinuata,L. ventricosa y C. tumida, dominan en aguas limpias, oxigenadas y baja temperatura. Las especies N. praecipua, S. goulardi, C. placentula, L. goeppertiana, N. clausii y N. symmetrica se encuentran en aguas cálidas, alta turbidez y poco oxigenadas. Las especies A. exiguum, R. sinuata, prevalecen en sitios con agua alcalina y baja conductividad y las especies N. symmetrica, C. tumida y L. ventricosa presentan una relación positiva con la conductividad y el pH de las aguas. Las especies estudiadas mostraron buenos indicios de su valor como indicadores de calidad del agua, sin embargo, debido a diferencias de interpretación por varios autores, es necesario realizar más estudios en otras cuencas hidrográficas en el país.

Abstract The tolerance of ten diatom species (Bacillariophyceae) to water's physico-chemical factors in the Sarapiqui River, Costa Rica. Benthic diatoms are the periphyton component most studied in Costa Rican rivers, yet there is still much to be known about their ecology. This study aims to contribute to this knowledge. Periphyton samples from six locations along the middle reach of Sarapiquí river and some of its tributaries were taken and analyzed from 2010 to 2012. A total count of 400 frustules was performed in each sample to obtain relative abundances of each species. Ten species, which were easily recognized at the light microscope, were analyzed here: Achnanthidium exiguum, Coconneis placentula, Cymbella tumida, Luticola goeppertiana, Luticola ventricosa, Navicula symmetrica, Nitzchia clausii, Nupela praecipua, Reimeria sinuata and Synedra goulardi. Their abundance was related to physico chemical data at each site for every sampling date (dissolved oxygen, temperature, conductivity, total suspended solids, turbidity, pH and alkalinity) with a canonical correspondence analysis (CCA) that allowed distinguishing three sectors along the river according to altitude. These sectors differed by substrate, riparian vegetation cover, and physic-chemical parameters, all of which resulted in differences in diatom species composition among them. Optimum values and tolerances form each environmental parameter were calculated for each species. Our results showed that A. exiguum, R. sinuata,L. ventricosa and C. tumida, were dominant in clean and well oxygenated waters with low temperatures. The species N. praecipua, S. goulardi, C. placentula, L. goeppertiana, N. clausii and N. symmetrica inhabited warm waters with high turbidity and low oxygen. The species A. exiguum, R. sinuata were dominant in sites with low alkalinity and conductivity, whereas species like N. symmetrica, C. tumida and L. ventricosa showed a positive relationship with conductivity and pH. The studied species showed good characteristics of their value as water quality indicators, yet due to different interpretations by several authors, it is necessary to perform further studies at more river basins in the country. Rev. Biol. Trop. 64 (1): 105-115. Epub 2016 March 01.

Melosira (Diatomeae) taxa from the Iguaçu River in southern Brazil / Táxons de Melosira (Diatomeae) para o rio Iguaçu, sul do Brasil

Abstract The study of the genus Melosira in plankton samples from the lower Iguaçu River revealed the presence of four taxa: Melosira undulata (Ehrenberg) Kützing var. undulata, M. undulata var. normanni Arnott, M. varians C. Agardh and M. muscigena Iwahashi. We present illustrations of the frustules using light microscopy (LM), descriptions, and comments about the morphology of the four taxa. The analysis of Melosira muscigena under scanning electron microscopy revealed unprecedented details of the ultrastructure, such as the shape and distribution of the rimoportulae at the valve mantle. This is the first record of Melosira undulata var. undulata and the second of M. muscigena in Brazil.

Resumo O estudo do gênero Melosira em amostras de plâncton do baixo rio Iguaçu revelou a presença de quatro táxons: Melosira undulata (Ehrenberg) Kützing var. undulata, M. undulata var. normanni Arnott, M. varians C. Agardh e M. muscigena Iwahashi. Apresentam-se ilustrações das frústulas usando microscopia óptica (MO), descrições e comentários sobre a morfologia dos quatro táxons. A análise de Melosira muscigena sob microscopia eletrônica de varredura revelou detalhes sem precedentes da ultraestrutura, como a forma e distribuição das rimopórtulas no manto da valva. Este é o primeiro registro de Melosira undulata var. undulata e o segundo de M. muscigena para o Brasil.

Diatoms Distribution in Ningbo Three-river Watershed during Summer / 法医学杂志

OBJECTIVES@#To explore the species, quantity and distribution of diatoms in Ningbo three-river watershed during summer and to provide scientific basis for forensic examination of drowning cases in the waters of Ningbo.@*METHODS@#Water samples were collected in July and August of 2015. Fourteen water sampling points were selected from the Yao River, the Fenghua River and the Yong River. The morphological features of diatom species and dominant diatoms were distinguished by microscope.@*RESULTS@#A total of 16 species of diatoms were detected in the Yao River, the Fenghua River and the Yong River. Melosira was the dominant species in the Yao River, and the quantity and richness were higher than in other rivers. The richness of Cyclotella in the Yong River was higher than in other rivers. The richness of Pinnularia and Licmophora were higher in the Fenghua River than in the Yao River and the Yong River.@*CONCLUSIONS@#The species and proportion of diatom is different in each river. Database of the species and relative composition for the diatoms in corresponding river is established, which may provide data support for forensic examination of drowning cases in Ningbo three-river watershed.

Distribution of Diatoms in Main Sections of Urban District Rivers with Drowning-prone in Chengdu / 法医学杂志

OBJECTIVES@#To explore the species distribution and constituent ratio of diatoms in main sections of urban district rivers where drowning occurs frequently in Chengdu.@*METHODS@#Total 39 water samples from the sampling points of 5 rivers （Jinjiang, Jinniu, Qingyang, Wuhou and Chenghua districts） in October 2014 were collected. The diatoms smear were made and the species distribution and constituent ratio of diatoms from the water samples were analyzed using biological microscope and acquisition system of digital microscope.@*RESULTS@#Total 21 species of diatoms were detected in main sections of urban district rivers in Chengdu. Significant differences in the dominant diatom species and proportions of the different rivers were observed, and there were different species existed in all sampling points of the upstream, midstream and downstream of the rivers.@*CONCLUSIONS@#The database of species map, species distribution and constituent ratio of diatoms in main sections of urban district rivers in Chengdu are preliminarily established, which has special meaning for the analysis and evaluation of falling location inference using diatoms test in case investigation.

Application of the identification diatom test in drowning / 中国法医学杂志

In forensic case, the location diagnosis determination of drowning has been one of the most important and dififcult diagnosis. Then diatom test is considered to be a relatively reliable method for the diagnosis of drowning. According to community characteristics inferred from diatoms into the different water region has been credibility. The study of the diatoms in different waters identiifcation is reference to the determination of the body drowned into the water area. In this paper, the research progress of diatom relevant biological characteristics and test methods on review for forensic workers is related to the further research and reference case in practice.