A comparative approach employing microCT for the analysis of Cenozoic foraminifera from the Brazilian carbonate equatorial platform.

Worldwide, some of the largest hydrocarbon reservoirs are located in tropical neritic carbonate deposits. Biostratigraphic and paleoenvironmental analyzes of these sedimentary records are often based on the study of foraminiferal assemblage. Foraminifera-based biozones are widely employed in the oil industry to support drilling processes that, alongside petrophysical prospecting, define interval favorable for exploiting hydrocarbon resources. Both scientific research and the petroleum industry, however, usually apply traditional petrographical and paleontological methods to analyze microfossil assemblages, especially for large benthic foraminifera. New, faster, and more accurate methods based on microCT analyzes have emerged as a valuable high-output tool to obtain high-resolution microfossil records for biostratigraphy and paleoenvironmental reconstructions. This method is also useful for the development of digital databases for artificial intelligence applications. MicroCT analyzes, therefore, lead to faster identification of foraminifera assemblage and support digital access to international foraminifera repositories and reference collections, introducing a new dimension in micropaleontological research.

Avaliação dos efeitos da movimentação dentária induzida sobre molares de ratos submetidos à luxação extrusiva / Evaluation of the effects of induced tooth movement on rat molars submitted to extrusive dislocation

A luxação extrusiva é caracterizada pela separação parcial ou total entre raiz e ligamento periodontal (LPD), podendo causar danos ao cemento por meio da compressão radicular contra o osso alveolar, além da ruptura do feixe vásculonervoso apical. A movimentação dentária induzida (MDI) é uma resposta de caráter inflamatório do conjunto LPD e osso alveolar, mesmas estruturas envolvidas na luxação extrusiva, a um estímulo provocado por uma força ortodôntica. Uma informação escassa na literatura é o efeito provocado pela movimentação dentária induzida em dentes que foram submetidos à luxação extrusiva (LE). O objetivo deste trabalho foi avaliar o efeito da movimentação dentária induzida sobre dentes submetidos à luxação extrusiva. Para a realização deste pesquisa, foram utilizados 40 ratos machos Wistar divididos em 4 grupos: o grupo controle (GC); o grupo Luxação Extrusiva (LE); o grupo Movimentação Dentária Induzida (MDI); e o grupo LEMDI. A LE foi exercida por uma força de 1.500Cn e a MDI por uma força de 50Cn por um período de 7 dias, após o qual os animais foram eutanasiados, as peças submetidas ao processamento laboratorial e obtidas lâminas que foram coradas por meio de hematoxilina e eosina. Foi realizada uma análise descritiva considerando-se quatro áreas ao redor da raiz mésio-vestibular: A1 região da crista óssea mesial, A2 região médio- cervical da face mesial, A3 região médio-apical da face distal e A4 região cervical da face. Em cada uma destas áreas foram observados os evento: reabsorção óssea frontal e à distância, reabsorção radicular, infiltrado infamatório e hemoragia no LPD.Os resultados mostraram que a associação entre MDI e LE provocou grande destruição óssea na crista óssea na A1, moderadas reabsorções radiculares na A3, ausência de infiltrado inflamatório em todas as áreas e hemorragia exuberante do LPD nas áreas 2 e 3. Nos demais grupos, tais observações foram ausentes ou quando presentes consideradas muito discretas. Conclui-se que, uma vez que a MDI em dentes submetidos a LE aumenta as áreas de hemorragia no LPD, provoca grande perda óssea frontal na crista alveolar, a MDI deveria ser interrompida, aguardando-se o período de reparo do LPD(AU)

Extrusive dislocation is characterized by partial or complete separation of the root and periodontal ligament (PDL), which can cause damage to the cementum by compressing the root against the alveolar bone, and rupture of the apical nervevascular bundle. Induced tooth movement (ITM) is an inflammatory response of the whole of the SMP and alveolar bone, the same structures involved in extrusive dislocation, to a stimulus caused by an orthodontic force. Little information is available in the literature on the effect caused by induced tooth movement in teeth that underwent extrusive luxation (EL). The aim of this study was to evaluate the effect of induced tooth movement on teeth submitted to extrusive dislocation. For this research 40 male Wistar rats were used, divided into 4 groups: The control group (CG); the Extrusive luxation group (EL); the Induced Tooth Movement group (ITM); and the LEMDI group. The LE was exerted by a force of 1,500Cn and the ITM by a force of 50Cn for a period of 7 days, after which the animals were euthanized, the specimens were submitted to laboratory processing and slides were obtained and stained using hematoxylin and eosin. A descriptive analysis was performed considering four areas around the mesial vestibular root: A1 mesial bone crest region, A2 mesial face midcervical region, A3 distal face mid-apical region and A4 face cervical region. In each of these areas the following events were observed: frontal and distal bone resorption, root resorption, infamatory infiltrate and hemorrhagia in the PDL. The results showed that the association between MDI and LE caused great bone destruction in the bone crest in A1, moderate root resorption in A3, absence of inflammatory infiltrate in all areas, and exuberant hemorrhage of the PDL in areas 2 and 3. In the other groups, such observations were absent or when present considered very discrete. We conclude that, since ITM in teeth submitted to EL increases the areas of hemorrhage in the PDL, causes great frontal bone loss in the alveolar ridge, ITM should be interrupted, waiting for the period of repair of the PDL(AU)

Neogene sharks and rays from the Brazilian 'Blue Amazon'.

The lower Miocene Pirabas Formation in the North of Brazil was deposited under influence of the proto-Amazon River and is characterized by large changes in the ecological niches from the early Miocene onwards. To evaluate these ecological changes, the elasmobranch fauna of the fully marine, carbonate-rich beds was investigated. A diverse fauna with 24 taxa of sharks and rays was identified with the dominant groups being carcharhiniforms and myliobatiforms. This faunal composition is similar to other early Miocene assemblages from the proto-Carribbean bioprovince. However, the Pirabas Formation has unique features compared to the other localities; being the only Neogene fossil fish assemblage described from the Atlantic coast of Tropical Americas. Phosphate oxygen isotope composition of elasmobranch teeth served as proxies for paleotemperatures and paleoecology. The data are compatible with a predominantly tropical marine setting with recognized inshore and offshore habitats with some probable depth preferences (e.g., Aetomylaeus groups). Paleohabitat of taxa particularly found in the Neogene of the Americas (†Carcharhinus ackermannii, †Aetomylaeus cubensis) are estimated to have been principally coastal and shallow waters. Larger variation among the few analyzed modern selachians reflects a larger range for the isotopic composition of recent seawater compared to the early Miocene. This probably links to an increased influence of the Amazon River in the coastal regions during the Holocene.