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1.
bioRxiv ; 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38585848

RESUMO

RNA binding proteins (RBPs) containing intrinsically disordered regions (IDRs) are present in diverse molecular complexes where they function as dynamic regulators. Their characteristics promote liquid-liquid phase separation (LLPS) and the formation of membraneless organelles such as stress granules and nucleoli. IDR-RBPs are particularly relevant in the nervous system and their dysfunction is associated with neurodegenerative diseases and brain tumor development. SERBP1 is a unique member of this group, being mostly disordered and lacking canonical RNA-binding domains. Using a proteomics approach followed by functional analysis, we defined SERBP1's interactome. We uncovered novel SERBP1 roles in splicing, cell division, and ribosomal biogenesis and showed its participation in pathological stress granules and Tau aggregates in Alzheimer's disease brains. SERBP1 preferentially interacts with other G-quadruplex (G4) binders, implicated in different stages of gene expression, suggesting that G4 binding is a critical component of SERBP1 function in different settings. Similarly, we identified important associations between SERBP1 and PARP1/polyADP-ribosylation (PARylation). SERBP1 interacts with PARP1 and its associated factors and influences PARylation. Moreover, protein complexes in which SERBP1 participates contain mostly PARylated proteins and PAR binders. Based on these results, we propose a feedback regulatory model in which SERBP1 influences PARP1 function and PARylation, while PARylation modulates SERBP1 functions and participation in regulatory complexes.

2.
PeerJ ; 11: e15776, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37671356

RESUMO

The initial radiation of Eosauropterygia during the Triassic biotic recovery represents a key event in the dominance of reptiles secondarily adapted to marine environments. Recent studies on Mesozoic marine reptile disparity highlighted that eosauropterygians had their greatest morphological diversity during the Middle Triassic, with the co-occurrence of Pachypleurosauroidea, Nothosauroidea and Pistosauroidea, mostly along the margins of the Tethys Ocean. However, these previous studies quantitatively analysed the disparity of Eosauropterygia as a whole without focussing on Triassic taxa, thus limiting our understanding of their diversification and morphospace occupation during the Middle Triassic. Our multivariate morphometric analyses highlight a clearly distinct colonization of the ecomorphospace by the three clades, with no evidence of whole-body convergent evolution with the exception of the peculiar pistosauroid Wangosaurus brevirostris, which appears phenotypically much more similar to nothosauroids. This global pattern is mostly driven by craniodental differences and inferred feeding specializations. We also reveal noticeable regional differences among nothosauroids and pachypleurosauroids of which the latter likely experienced a remarkable diversification in the eastern Tethys during the Pelsonian. Our results demonstrate that the high phenotypic plasticity characterizing the evolution of the pelagic plesiosaurians was already present in their Triassic ancestors, casting eosauropterygians as particularly adaptable animals.


Assuntos
Fósseis , Fenótipo , Répteis , Animais , Adaptação Fisiológica , Análise Multivariada , Répteis/anatomia & histologia , Répteis/classificação , Fósseis/anatomia & histologia , Filogenia
3.
Curr Biol ; 33(14): 3011-3016.e3, 2023 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-37352853

RESUMO

The histology of bone can be preserved virtually unaltered for hundreds of millions of years in fossils from all environments and all vertebrate taxa, giving rise to the flourishing field of paleohistology.1 The shafts of long bones are formed by the apposition of periosteal bone tissue, similar to the growth of wood, and preserve, an often cyclical, record of the growth of the individual and events in its life history. One such event is sexual maturation or puberty, during which hormonal changes transform the juvenile into a sexually mature adult. Puberty has been well studied in humans and some other living vertebrates. Here, we describe puberty in Keichousaurus, a small sexually dimorphic and live-bearing marine reptile from Middle Triassic rocks of SW China, about 240 million years old. Using a combination of bone histology and morphology, we detected puberty2 as one of the four life stages (the others being fetus, juvenile, and adult). Adult Keichousaurus males have a more robust humerus than females, with pronounced muscle attachment sites and a triangular shaft cross section. Midshaft sections of the humeri of the males show the transition from the rounded juvenile cross section to the triangular adult cross section, as reflected in the contour of the growth marks. This shape change is produced by differential bone apposition of the periosteum, presumably triggered by sex hormones, as in humans,3 and influenced by changes in loading regime during puberty. This is the first report of puberty in a fossil amniote.


Assuntos
Répteis , Masculino , Feminino , Animais , Répteis/fisiologia , Envelhecimento , Maturidade Sexual , Fósseis
4.
BMC Ecol Evol ; 23(1): 12, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-37072698

RESUMO

According to a longstanding paradigm, aquatic amniotes, including the Mesozoic marine reptile group Ichthyopterygia, give birth tail-first because head-first birth leads to increased asphyxiation risk of the fetus in the aquatic environment. Here, we draw upon published and original evidence to test two hypotheses: (1) Ichthyosaurs inherited viviparity from a terrestrial ancestor. (2) Asphyxiation risk is the main reason aquatic amniotes give birth tail-first. From the fossil evidence, we conclude that head-first birth is more prevalent in Ichthyopterygia than previously recognized and that a preference for tail-first birth likely arose in derived forms. This weakens the support for the terrestrial ancestry of viviparity in Ichthyopterygia. Our survey of extant viviparous amniotes indicates that fetal orientation at birth reflects a broad diversity of factors unrelated to aquatic vs. terrestrial habitat, further undermining the asphyxiation hypothesis. We propose that birth preference is based on parturitional mechanics or carrying efficiency rather than habitat.


Assuntos
Fósseis , Répteis , Animais , Répteis/anatomia & histologia , Feto
5.
J Morphol ; 284(2): e21550, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36538608

RESUMO

While the occurrence of skeletal pathologies in Middle Triassic marine reptiles has been poorly documented until now, massive accumulations of bone remains from the Germanic Basin provide the opportunities for documentation. Herein, we describe skeletal abnormalities in the Middle Triassic bone material from the Vossenveld Formation of Winterswijk, the Netherlands. The aim of the study is to distinguish in the studied bones pathologies resulting from malady or trauma and taphonomic alterations. Furthermore, an attempt was made to assess on how the pathologies also represent paleoecological data. Our survey led to the identification of one broken and healed bone, one case of abnormal coossification, and one case of posttraumatic fibro-osseous dysplasia. While the latter two pathologies give little insight into the ecology and function of the affected animals, the fractured dentary is attributed to Nothosaurus marchicus, a common sauropterygian macropredator. It proves that the individual survived long enough to heal, despite the injury hampering its hunting potential. One abnormally shaped humerus is interpreted as postmortem taphonomic deformation, emphasizing the necessity of utilization of detailed diagnostics to distinguish actual paleopathologies from nonbiological distortion.


Assuntos
Fósseis , Répteis , Animais , Répteis/anatomia & histologia , Úmero
6.
Q J Exp Psychol (Hove) ; 76(7): 1497-1514, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35848220

RESUMO

Retrieved memories of past events are often inaccurate. The scenario construction model (SCM) postulates that during encoding, only the gist of an episode is stored in the episodic memory trace and during retrieval, information missing from that trace is constructed from semantic information. The current study aimed to find behavioural evidence for semantic construction in a realistic, yet controlled setting by introducing a completely new paradigm and adjusted memory tests that measure semantic construction. Using a desktop virtual reality (VR), participants navigated through a flat in which some household objects appeared in unexpected rooms, creating conflicts between the experienced episode and semantic expectations. The manipulation of congruence enabled us to identify influences from semantic information in cases of episodic memory failure during recall. Besides, we controlled for objects to be task-relevant or task-irrelevant to the sequence of action. In addition to an established old/new recognition task we introduced spatial and temporal recall measures as possible superior memory measures quantifying semantic construction. The recognition task and the spatial recall revealed that both congruence and task-relevance predicted correct episodic memory retrieval. In cases of episodic memory failure, semantic construction was more likely than guessing and occurred more frequently for task-irrelevant objects. In the temporal recall object-pairs belonging to the same semantic room-category were temporally clustered together compared with object-pairs from different semantic categories (at the second retrieval delay). Taken together, our findings support the predictions of the SCM. The new VR paradigm, including the new memory measures appears to be a promising tool for investigating semantic construction.


Assuntos
Memória Episódica , Humanos , Semântica , Rememoração Mental , Reconhecimento Psicológico
7.
Swiss J Palaeontol ; 141(1): 17, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36317153

RESUMO

Proganochelys quenstedtii represents the best-known stem turtle from the Late Triassic, with gross anatomical and internal descriptions of the shell, postcranial bones and skull based on several well-preserved specimens from Central European fossil locations. We here report on the first specimen of P. quenstedtii from the Late Triassic (Klettgau Formation) Frickberg near the town of Frick, Canton Aargau, Switzerland. Similar to other Late Triassic 'Plateosaurus-bearing bonebeds', Proganochelys is considered to be a rare faunal element in the Swiss locality of Frick as well. The specimen, which is largely complete but was found only partially articulated and mixed with large Plateosaurus bones, overall resembles the morphology of the classical specimens from Germany. Despite being disarticulated, most skull bones could be identified and micro-computed tomography (CT) scanning of the posterior skull region reveals new insights into the braincase and neurovascular anatomy, as well as the inner ear region. These include the presence of a fenestra perilymphatica, potentially elongated cochlear ducts, and intense vascularization of small tubercles on the posterior end of the skull roof, which we interpret as horn cores. Other aspects of the skull in the braincase region, such as the presence or absence of a supratemporal remain ambiguous due to the fusion of individual bones and thus lack of visible sutures (externally and internally). Based on the size of the shell and fusion of individual elements, the specimen is interpreted as a skeletally mature animal. Supplementary Information: The online version contains supplementary material available at 10.1186/s13358-022-00260-4.

8.
Nat Commun ; 13(1): 6089, 2022 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-36284092

RESUMO

Acoustic communication, broadly distributed along the vertebrate phylogeny, plays a fundamental role in parental care, mate attraction and various other behaviours. Despite its importance, comparatively less is known about the evolutionary roots of acoustic communication. Phylogenetic comparative analyses can provide insights into the deep time evolutionary origin of acoustic communication, but they are often plagued by missing data from key species. Here we present evidence for 53 species of four major clades (turtles, tuatara, caecilian and lungfish) in the form of vocal recordings and contextual behavioural information accompanying sound production. This and a broad literature-based dataset evidence acoustic abilities in several groups previously considered non-vocal. Critically, phylogenetic analyses encompassing 1800 species of choanate vertebrates reconstructs acoustic communication as a homologous trait, and suggests that it is at least as old as the last common ancestor of all choanate vertebrates, that lived approx. 407 million years before present.


Assuntos
Evolução Biológica , Vertebrados , Animais , Filogenia , Vertebrados/genética , Acústica , Comunicação
9.
PeerJ ; 10: e13818, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36046504

RESUMO

In 2009, the historical mount of the holotype of Nothosaurus mirabilis from the Upper Muschelkalk of Oschenberg (Laineck Mountain Range, near Bayreuth, southern Germany) was disassembled and the original postcranial skeleton was reworked and remounted in find position. Its morphology is described and figured for the first time in detail. Further on, a thorough overview of the sedimentary environment and the historical activities around the Upper Muschelkalk quarries in the vicinity of Bayreuth is given. The holotype of N. mirabilis is one out of only two fairly complete nothosaur skeletons known from the Bayreuth Upper Muschelkalk and greatly emends our knowledge of the morphology of the species and the genus. It will further allow an assignment of isolated elements to this taxon. The specimen consists of an articulated and complete neck and anterior trunk vertebral column as well as several articulated parts of the anterior tail region. The sacral region is partially preserved but disarticulated. Besides vertebrae, ribs and gastral fragments, both humeri, the right femur, few zeugopodial and autopodial elements, and the right pelvic girdle are preserved. The very high neural spines of the holotype are stabilized by a supersized zygosphene-zygantrum articulation reaching far dorsally. Together with the large intercentral spaces this character suggests lateral undulation of the trunk region during fast swimming whereas propelling with the broad and wing-shaped humerus and the flat ulna was used during slower swimming. The total body length for this not fully grown individual is reconstructed as between 290 to 320 cm. Preservation, degree of completeness, and articulation of the individual is unique. The skull and shoulder girdle are both lost, whereas articulated strings of the vertebral column have turned and appendicular bones have shifted posteriorly or anteriorly, respectively, indicating water movements and possibly also scavenging.


Assuntos
Mirabilis , Coluna Vertebral/anatomia & histologia , Crânio/anatomia & histologia , Úmero , Fêmur
10.
Swiss J Palaeontol ; 141(1): 12, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35844249

RESUMO

The Alpine Prosanto Formation (Middle Triassic) cropping out in the Ducan region in eastern Switzerland has yielded a rich fish and reptile fauna. Here, we present new pachypleurosaur remains from the upper part of the formation (Early Ladinian), similar to the previously known pachypleurosaurs from the Middle Triassic UNESCO World Heritage Site of Monte San Giorgio in southern Switzerland/northern Italy. From these remains, a new pachypleurosaur species, Prosantosaurus scheffoldi nov. gen. et spec., is described on the basis of six fairly complete skeletons, one disarticulated specimen and an isolated skull. As is typical for pachypleurosaurs and most other Triassic marine reptiles, the new taxon is based to a large degree on a combination of characters (e.g., nasals articulating broadly with the anterior margins of the prefrontals and lacking posterior processes; postorbitals with rounded anterior processes that articulate with the postfrontals anterolaterally) rather than on many unambiguous autapomorphies, although a few of the latter were found including (1) a premaxilla which is excluded from entering both the external and internal nares and (2) a parietal, which is distinctly longer than wide and carrying distinct anterolaterally angled processes. Phylogenetic relationships of the new taxon are tested within European Pachypleurosauria, revealing that the new species is the sister taxon to a clade including Serpianosaurus, Proneusticosaurus, and the monophyletic Neusticosaurus spp. Mapping of palaeogeographic and stratigraphical distribution of valid European pachypleurosaurs shows that a formerly proposed scenario of migration of pachypleurosaurs from the eastern Palaeotethys during the Olenekian into the Germanic Basin and a subsequent diversification and invasion during the Anisian into the intraplatform basins of the South Alpine realm must be re-assessed. The exceptional preservation and preparation of the Ducan fossils further allow the description of tooth replacement patterns for the first time in a European pachypleurosaur species. The "alveolarization" of replacement teeth, the horizontal replacement pattern, and the subsequent remodelling of the functional alveoli during tooth replacement supports the monophyly of Sauropterygia as discussed before. Supplementary Information: The online version contains supplementary material available at 10.1186/s13358-022-00254-2.

11.
Neural Comput ; 34(9): 1841-1870, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35896150

RESUMO

Many studies have suggested that episodic memory is a generative process, but most computational models adopt a storage view. In this article, we present a model of the generative aspects of episodic memory. It is based on the central hypothesis that the hippocampus stores and retrieves selected aspects of an episode as a memory trace, which is necessarily incomplete. At recall, the neocortex reasonably fills in the missing parts based on general semantic information in a process we call semantic completion. The model combines two neural network architectures known from machine learning, the vector-quantized variational autoencoder (VQ-VAE) and the pixel convolutional neural network (PixelCNN). As episodes, we use images of digits and fashion items (MNIST) augmented by different backgrounds representing context. The model is able to complete missing parts of a memory trace in a semantically plausible way up to the point where it can generate plausible images from scratch, and it generalizes well to images not trained on. Compression as well as semantic completion contribute to a strong reduction in memory requirements and robustness to noise. Finally, we also model an episodic memory experiment and can reproduce that semantically congruent contexts are always recalled better than incongruent ones, high attention levels improve memory accuracy in both cases, and contexts that are not remembered correctly are more often remembered semantically congruently than completely wrong. This model contributes to a deeper understanding of the interplay between episodic memory and semantic information in the generative process of recalling the past.


Assuntos
Memória Episódica , Atenção , Rememoração Mental , Semântica
12.
Palaontol Z ; 96(2): 289-302, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35645412

RESUMO

Two recently found dentaries from the Lower Muschelkalk of Winterswijk (The Netherlands) and from the Upper Muschelkalk of an outcrop in the vicinity of Hünfeld (Hesse, Germany) are studied and compared to lower jaws of placodonts. As a result, the here described specimens can be assigned to Placodus cf. gigas. However, this assignment should be regarded as preliminary due to the isolated nature of the material. More diagnostic material is necessary to validate this affiliation. A certain morphological variability in P. gigas dentaries that had been pointed out before is also obvious among the new material. Placodus gigas has a wide paleogeography and stratigraphic range and a revision of the material assigned to P. gigas with new methods is overdue but beyond the scope of the current paper. The dentary from Hünfeld is with about 4 cm preserved length the smallest so far known dentary of a Placodus. It provides interesting insights in morphological changes during ontogeny and reveals differences in trajectories when compared to dentaries of different ontogenetic stages of Cyamodus hildegardis.

13.
Swiss J Palaeontol ; 141(1): 1, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35250843

RESUMO

An important component of the Alpine vertebrate record of Late Triassic age derives from the Kössen Formation, which crops out extensively in the eastern Alps. Here, we present an isolated and only partially preserved large rib, which carries an osteoderm on a low uncinate process. Osteological comparison indicates that the specimen likely belongs to a small clade of marine reptiles, Saurosphargidae. Members of the clade are restricted to the western (today Europe) and eastern margins of the Tethys (today China) and were so far known only from the Anisian stage of the Middle Triassic. The assignment of the new find to cf. Saurosphargidae, with potential affinities to the genus Largocephalosaurus from the Guanling Formation of Yunnan and Guizhou Provinces, China, would extend the occurrence of the clade about 35 million years into the Late Triassic.

14.
Science ; 374(6575): eabf5787, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-34941418

RESUMO

Body sizes of marine amniotes span six orders of magnitude, yet the factors that governed the evolution of this diversity are largely unknown. High primary production of modern oceans is considered a prerequisite for the emergence of cetacean giants, but that condition cannot explain gigantism in Triassic ichthyosaurs. We describe the new giant ichthyosaur Cymbospondylus youngorum sp. nov. with a 2-meter-long skull from the Middle Triassic Fossil Hill Fauna of Nevada, USA, underscoring rapid size evolution despite the absence of many modern primary producers. Surprisingly, the Fossil Hill Fauna rivaled the composition of modern marine mammal faunas in terms of size range, and energy-flux models suggest that Middle Triassic marine food webs were able to support several large-bodied ichthyosaurs at high trophic levels, shortly after ichthyosaur origins.


Assuntos
Evolução Biológica , Tamanho Corporal , Cetáceos/anatomia & histologia , Fósseis , Répteis/anatomia & histologia , Animais , Organismos Aquáticos , Cetáceos/fisiologia , Simulação por Computador , Dieta , Ecossistema , Cadeia Alimentar , Filogenia , Répteis/classificação , Répteis/fisiologia , Crânio/anatomia & histologia , Vertebrados/anatomia & histologia , Vertebrados/fisiologia
15.
Proc Biol Sci ; 288(1955): 20211166, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34284632

RESUMO

Histology-based skeletochronology is a widely used approach to determine the age of an individual, and is based on the assumption that temporal cessations or decelerations of bone growth lead to incremental growth marks (GM), reflecting annual cycles. We studied the reliability of histology-based skeletochronology in a variety of extant tetrapods by comparing two different approaches: petrographic ground sections versus stained microtomized sections. Each bone was cut into two corresponding halves at its growth centre in order to apply both approaches to one and the same sample. None of the samples unequivocally revealed the actual age of the specimens, but truly concerning is the fact that the majority of samples even led to conflicting age estimates between the two approaches. Although the microtomized sections tended to yield more GM and thus indicated an older age than the ground sections, the contrary also occurred. Such a pronounced ambiguity in skeletochronological data strongly challenges the value of the respective age determinations for both extant and extinct animals. We conclude that much more research on the fundamental methodological side of skeletochronology-especially regarding the general nature and microscopic recognition of GM-is required.


Assuntos
Desenvolvimento Ósseo , Osso e Ossos , Animais , Reprodutibilidade dos Testes
16.
NASN Sch Nurse ; 35(4): 219-223, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32496933

RESUMO

The Framework for 21st Century School Nursing Practice™, created by the National Association of School Nurses (NASN), explains school nursing practice, providing guidance, organization, prioritization, and meaning. This is the second article in a series for The Framework for 21st Century School Nursing Practice. This article focuses on case management, one of the practice components in the principle of care coordination. Case management focuses on school nurse support of individual at-risk students and collaborative actions to reduce barriers to their academic success. This article will clarify how the terms care coordination and case management are used in context of the Framework and provide an example to help the reader apply the concept to practice. Washington's School Nurse Case Management Program will serve as a model. The program outlines evidence for effective practice and shares practical examples of how school nurses can implement case management into their daily work. Any school nurse, no matter how large or small their workload, can provide case management.


Assuntos
Serviços de Enfermagem Escolar , Administração de Caso , Humanos
17.
J Adv Nurs ; 75(12): 3677-3688, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31566808

RESUMO

AIMS: To develop a theory describing the processes and actions involved with school nurse case management for school-aged children with chronic conditions in the K12 system. DESIGN: Case management is an essential practice for the school nurse. Little is known about actual case management practice in real-world settings. Grounded theory methodology following a literature-based conceptual model of school nurse case management. METHODS: A purposive maximum variation sampling was used for data collection and analysis. Semi-structured interviews conducted in-person and via conferencing software from January to March 2017 with school nurses practicing in Washington State until data saturation was achieved. A condition lasting at least 6 months was also used to define a chronic condition. RESULTS: In all, 14 school nurses with an average of 12 years of experience were interviewed. Analysis revealed that the core strategy used by participating nurses for case management involved navigating through ambiguity; balancing multiple roles; seeking guidance and training; acknowledging imperfect functioning and navigating poor system supports. CONCLUSION: The findings suggest that actual school nurse case management practice differs from best practice recommendations. Participants did not discuss health promotion or environmental management and did not act to set goals or prioritize care as suggested in the literature. IMPACT: This article informs nursing leadership of the real-world challenges faced by nurses performing case management in the school setting. These findings indicate that improvements in system supports and training, together with tolerance for the challenges nurses face in providing such care, might improve case management practice in the schools.


Assuntos
Atitude do Pessoal de Saúde , Administração de Caso/organização & administração , Serviços de Enfermagem Escolar , Adolescente , Adulto , Criança , Pré-Escolar , Doença Crônica/enfermagem , Atenção à Saúde/organização & administração , Teoria Fundamentada , Humanos , Entrevistas como Assunto , Liderança , Pessoa de Meia-Idade , Serviços de Saúde Escolar/organização & administração , Instituições Acadêmicas , Washington
18.
Sci Rep ; 9(1): 10430, 2019 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-31320733

RESUMO

Unlike any other tetrapod, turtles form their dorsal bony shell (carapace) not from osteoderms, but by contribution of the ribs and vertebrae that expand into the dermis to form plate-like shell components. Although this was known from embryological studies in extant turtles, important steps in this evolutionary sequence have recently been highlighted by the Triassic taxa Pappochelys, Eorhynchochelys and Odontochelys, and the Permian Eunotosaurus. The discovery of Pappochelys shed light on the origin of the ventral bony shell (plastron), which formed from enlarged gastralia. A major question is whether the turtle shell evolved in the context of a terrestrial or aquatic environment. Whereas Odontochelys was controversially interpreted as aquatic, a terrestrial origin of turtles was proposed based on evidence of fossorial adaptations in Eunotosaurus. We report palaeohistological data for Pappochelys, a taxon that exemplifies earlier evolutionary stages in the formation of the bony shell than Odontochelys. Bone histological evidence reveals (1) evolutionary changes in bone microstructure in ribs and gastralia approaching the turtle condition and (2) evidence for a predominantly amphibious or fossorial mode of life in Pappochelys, which support the hypothesis that crucial steps in the evolution of the shell occurred in a terrestrial rather than fully aquatic environment.


Assuntos
Exoesqueleto/anatomia & histologia , Fósseis/anatomia & histologia , Tartarugas/anatomia & histologia , Adaptação Fisiológica/fisiologia , Animais , Evolução Biológica , Placas Ósseas , Filogenia , Costelas/anatomia & histologia , Crânio/anatomia & histologia , Coluna Vertebral/anatomia & histologia
19.
Anat Rec (Hoboken) ; 302(10): 1770-1791, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30989828

RESUMO

Isolated ribs and vertebrae of Middle Triassic sauropterygians are studied. The vertebrae have a well-defined large cavity in their centra, which is a unique feature and is without any modern analogue. The articular facets of vertebrae are made of endochondral bone including calcified as well as uncalcified cartilage. Vertebrae are pachyosteosclerotic in the pachypleurosaurs Neusticosaurus and Serpianosaurus from the Alpine Triassic, and osteosclerotic in the placodont, in the medium-sized Nothosaurus marchicus, and in the pachypleurosaur Anarosaurus. In large Nothosaurus specimens, the vertebrae are cavernous. The ribs of all sampled specimens are osteosclerotic, which resembles the microanatomy of long bones in all studied taxa. The proximal to medial part of ribs mainly consists of a compact periosteal cortex surrounding an inner endosteal territory. Toward the distal end of the ribs, the periosteal thickness decreases whereas the endosteal territory increases. Despite a shift from periosteal versus endosteal tissues, global rib compactness remains relatively constant. Osteosclerosis in ribs and vertebrae is reached by the same processes as in the long bones: by a relative increase in cortex thickness that is coupled by a reduction of the medullary cavity, by the persistence of calcified cartilage, and by an inhibition of remodeling although some resorption may occur but without complete redeposition of bone. Processes differ from those observed in Permian marine reptiles and some mosasaurines, where either extensive remodeling or inhibition of bone resorption leads to osteosclerosis. Besides differences regarding the microanatomy, all studied bones of a taxon are consistent in their bone tissue type. Anat Rec, 302:1770-1791, 2019. © 2019 American Association for Anatomy.


Assuntos
Adaptação Fisiológica , Evolução Biológica , Dinossauros/anatomia & histologia , Costelas/anatomia & histologia , Coluna Vertebral/anatomia & histologia , Animais , Fósseis/anatomia & histologia , Natação/fisiologia
20.
Adv Mater ; 30(37): e1704679, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29921016

RESUMO

The quest for advanced designer adsorbents for air filtration and monitoring hazardous trace gases has recently been more and more driven by the need to ensure clean air in indoor, outdoor, and industrial environments. How to increase safety with regard to personal protection in the event of hazardous gas exposure is a critical question for an ever-growing population spending most of their lifetime indoors, but is also crucial for the chemical industry in order to protect future generations of employees from potential hazards. Metal-organic frameworks (MOFs) are already quite advanced and promising in terms of capacity and specific affinity to overcome limitations of current adsorbent materials for trace and toxic gas adsorption. Due to their advantageous features (e.g., high specific surface area, catalytic activity, tailorable pore sizes, structural diversity, and range of chemical and physical properties), MOFs offer a high potential as adsorbents for air filtration and monitoring of hazardous trace gases. Three advanced topics are considered here, in applying MOFs for selective adsorption: (i) toxic gas adsorption toward filtration for respiratory protection as well as indoor and cabin air, (ii) enrichment of hazardous gases using MOFs, and (iii) MOFs as sensors for toxic trace gases and explosives.

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