scholarly journals Trabecular bone architecture in the stylopod epiphyses of mustelids (Mammalia, Carnivora)

2019 ◽  
Vol 6 (10) ◽  
pp. 190938
Author(s):  
E. Amson ◽  
B. M. Kilbourne
Keyword(s):  
Trabecular Bone ◽  
A Priori ◽  
Potential Effect ◽  
Bone Architecture ◽  
Evolutionary Transitions ◽  
The Family ◽  
Bone Fraction ◽  
Phylogenetic Framework ◽  
Functional Analyses ◽  
Range Of Variation

Mustelidae, a carnivoran clade that includes for instance weasels, badgers, otters and martens, has undergone several evolutionary transitions of lifestyle, resulting in specializations for fossorial, natatorial and scansorial locomotion, in addition to more generalized species. The family is therefore regarded as offering an adequate framework for morpho-functional analyses. However, the architecture of the epiphyseal trabecular bone, which is argued to be particularly responsive to the biomechanical environment, has never been studied. Here, we quantify trabecular bone parameters of the proximal and distal epiphyses of the humerus and femur in 29 species of mustelids and assess the differences of these parameters among groups defined a priori based on the aforementioned locomotor types. The parameters are assessed in a phylogenetic framework, taking into account the potential effect on an individual's body mass. The range of variation described by the acquired parameters is relatively restricted when compared to that of other clades. Generalists, however, are featuring a wider range of variation than the other types. While clear discrimination of locomotor types is difficult, some differences were highlighted by our analysis, such as a greater bone fraction associated with the natatorial taxa, which we discuss in a functional context.

scholarly journals Further steps on the reconstruction of convex polyominoes from orthogonal projections

2021 ◽  
Author(s):  
Paolo Dulio ◽  
Andrea Frosini ◽  
Simone Rinaldi ◽  
Lama Tarsissi ◽  
Laurent Vuillon
Keyword(s):  
Discrete Geometry ◽  
Convex Subset ◽  
Convex Sets ◽  
A Priori ◽  
Orthogonal Projections ◽  
Reconstruction Process ◽  
Combinatorial Properties ◽  
The Family ◽  
Discrete Counterpart ◽  
Interior Part

AbstractA remarkable family of discrete sets which has recently attracted the attention of the discrete geometry community is the family of convex polyominoes, that are the discrete counterpart of Euclidean convex sets, and combine the constraints of convexity and connectedness. In this paper we study the problem of their reconstruction from orthogonal projections, relying on the approach defined by Barcucci et al. (Theor Comput Sci 155(2):321–347, 1996). In particular, during the reconstruction process it may be necessary to expand a convex subset of the interior part of the polyomino, say the polyomino kernel, by adding points at specific positions of its contour, without losing its convexity. To reach this goal we consider convexity in terms of certain combinatorial properties of the boundary word encoding the polyomino. So, we first show some conditions that allow us to extend the kernel maintaining the convexity. Then, we provide examples where the addition of one or two points causes a loss of convexity, which can be restored by adding other points, whose number and positions cannot be determined a priori.

FAMILY DIABETES AND MAIN NONCOMMUNICABLE DISEASES: THE DESCRIBED AND POTENTIAL EFFECT OF METFORMIN (remembering Vladimir Dilman)

2020 ◽  
pp. 713-720
Author(s):  
Л. М. Берштейн
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Potential Effect ◽  
Noncommunicable Diseases ◽  
The Family ◽  
Whole Number ◽  
Long Time ◽  
Relationship Of ◽  
Antidiabetic Biguanides

Работа посвящена двум медико-биологическим проблемам - семейному диабету (имея в виду наличие случаев сахарного диабета 2-го типа в семье, в том числе в разных поколениях), а также особенностям его связей с основными неинфекционными заболеваниями человека и приурочена к юбилею известнейшего отечественного специалиста (теоретика и врача) в области геронтологии и эндокринологии профессора В. М. Дильмана. Широко признанные труды Владимира Михайловича, основанные на оригинальных идеях и породившие важные практические следствия (включая применение антидиабетических бигуанидов в не использовавшихся до него областях, необходимость устранения метаболической иммунодепрессии, учета изменений с возрастом на уровне гипоталамического порога в различных гомеостатических системах и целого ряда других предложений), как представляется, в течение долгого времени будут питать интеллектуальным материалом и стимулировать к дальнейшему поиску его последователей и специалистов, которым еще предстоит окунуться в область, очерченную В. М. Дильманом и интересовавшую его в течение многих лет. The work discusses the two biomedical problems: family diabetes (bearing in mind the presence of cases of type 2 diabetes mellitus in the family, including its different generations) and the features of relationship of family diabetes with major non-communicable human diseases (NCDs). The paper is timed to the anniversary of the famous - in our country and abroad - expert in the field of gerontology and endocrinology, Professor V. M. Dilman. The widely recognized works of V. M. Dilman, based on original ideas and giving rise to important practical consequences (including the use of antidiabetic biguanides in areas not studied before him, the need to eliminate metabolic immunodepression, to take into account the changes with age at the level of the hypothalamic threshold in various homeostatic systems and a whole number of other essential proposals), which for a long time, as it seems, will stimulate the further scientific search of his followers and specialists, who have yet to get acquainted with the area that attracted Prof. Dilman and interested him for many years.

Architectural changes of trabecular bone caused by the remodeling process

2005 ◽  
Vol 874 ◽  
Author(s):  
Richard Weinkamer ◽  
Markus A. Hartmann ◽  
Yves Brechet ◽  
Peter Fratzl
Keyword(s):  
Trabecular Bone ◽  
Feedback Loop ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Bone Volume ◽  
Bone Architecture ◽  
Mechanical Problem ◽  
Bone Volume Fraction ◽  
Obvious Effect ◽  
Trabecular Bone Architecture

AbstractUsing a stochastic lattice model we have studied the architectural changes of trabecular bone occurring while the structure is remodeled. Our model considers the mechanical feedback loop, which control the remodeling process. A fast algorithm was employed to solve approximately the mechanical problem. A general feature of the model is that a networklike structure emerges, which further coarsens while the bone volume fraction remains unchanged. Decreasing the mechanical response of the system by either lowering the external load or the internal mechano-sensitivity leads not only to a reduction of the bone volume fraction, but results in topological changes of the trabecular bone architecture, where the loss of horizontal trabeculae is the most obvious effect.

scholarly journals The Vav GEF Family: An Evolutionary and Functional Perspective

Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 465 ◽  
Author(s):  
Sonia Rodríguez-Fdez ◽  
Xosé R. Bustelo
Keyword(s):  
Tyrosine Kinases ◽  
Rho Gtpases ◽  
Nucleotide Exchange ◽  
Structural Domains ◽  
Evolutionary Transitions ◽  
Functional Perspective ◽  
Nucleotide Exchange Factors ◽  
The Family ◽  
Unicellular Organisms ◽  
Phylogenetic Perspective

Vav proteins play roles as guanosine nucleotide exchange factors for Rho GTPases and signaling adaptors downstream of protein tyrosine kinases. The recent sequencing of the genomes of many species has revealed that this protein family originated in choanozoans, a group of unicellular organisms from which animal metazoans are believed to have originated from. Since then, the Vav family underwent expansions and reductions in its members during the evolutionary transitions that originated the agnates, chondrichthyes, some teleost fish, and some neoaves. Exotic members of the family harboring atypical structural domains can be also found in some invertebrate species. In this review, we will provide a phylogenetic perspective of the evolution of the Vav family. We will also pay attention to the structure, signaling properties, regulatory layers, and functions of Vav proteins in both invertebrate and vertebrate species.

scholarly journals La familia Rhodomelaceae (Ceramiales, Rhodophyta) en la costa del estado de Michoacán, México

2017 ◽  
pp. 89
Author(s):  
Abel Sentíes-G.
Keyword(s):  
New Records ◽  
Anatomic Variation ◽  
The Family ◽  
Presence And Absence ◽  
Range Of Variation ◽  
Made In

In this paper, the Rhodomelaceae family intertidal representants are characterized in the coasts of Michoacan. A list of taxonomic characters and a preliminary weight of them are proposed for use in the determination and diagnosis of the species in each genus of the family. The elaboration of a sinoptic key for the genera and species investigated was carried out. An analys is about the distribution of the species through the litoral of Michoacan was made and some of the causes for the presence and absence of them are discussed , considering mainly the habitat where they grow. An emphasis was made in morphologic and anatomic variation between the previous records and our material, and in some cases, a new range of variation is given. . The analyzed flora is composed of fourteen species, distributed in five genus, pointing out six new records for Mexico in its tropical coasts: Polysiphonia confusa, P.scopulorum, Chondria arcuata, C. daswhylla, Laurencia clarionensis y L. hancockii.

Changes in trabecular bone architecture in women during pregnancy

1999 ◽  
Vol 106 (5) ◽  
pp. 432-438 ◽  
Author(s):  
Seyed Mohsen Shahtaheri ◽  
Jean E. Aaron ◽  
David R. Johnson ◽  
David W. Purdie
Keyword(s):  
Trabecular Bone ◽  
Bone Architecture ◽  
Trabecular Bone Architecture

scholarly journals Evolution of the Gekkotan Adhesive System: Does Digit Anatomy Point to One or More Origins?

2019 ◽  
Vol 59 (1) ◽  
pp. 131-147 ◽  
Author(s):  
Anthony P Russell ◽  
Tony Gamble
Keyword(s):  
Adhesive System ◽  
Adhesive Contact ◽  
Ancestral State ◽  
Evolutionary Transitions ◽  
Multiple Origins ◽  
Published Evidence ◽  
Enormous Variation ◽  
Phylogenetic Framework ◽  
Competing Hypotheses ◽  
Necessary And Sufficient

Abstract Recently-developed, molecularly-based phylogenies of geckos have provided the basis for reassessing the number of times adhesive toe-pads have arisen within the Gekkota. At present both a single origin and multiple origin hypotheses prevail, each of which has consequences that relate to explanations about digit form and evolutionary transitions underlying the enormous variation in adhesive toe pad structure among extant, limbed geckos (pygopods lack pertinent features). These competing hypotheses result from mapping the distribution of toe pads onto a phylogenetic framework employing the simple binary expedient of whether such toe pads are present or absent. It is evident, however, that adhesive toe pads are functional complexes that consist of a suite of integrated structural components that interact to bring about adhesive contact with the substratum and release from it. We evaluated the competing hypotheses about toe pad origins using 34 features associated with digit structure (drawn from the overall form of the digits; the presence and form of adhesive scansors; the proportions and structure of the phalanges; aspects of digital muscular and tendon morphology; presence and form of paraphalangeal elements; and the presence and form of substrate compliance-enhancing structures). We mapped these onto a well-supported phylogeny to reconstruct their evolution. Nineteen of these characters proved to be informative for all extant, limbed geckos, allowing us to assess which of them exhibit co-occurrence and/or clade-specificity. We found the absence of adhesive toe pads to be the ancestral state for the extant Gekkota as a whole, and our data to be consistent with independent origins of adhesive toe pads in the Diplodactylidae, Sphaerodactylidae, Phyllodactylidae, and Gekkonidae, with a strong likelihood of multiple origins in the latter three families. These findings are consistent with recently-published evidence of the presence of adhesively-competent digits in geckos generally regarded as lacking toe pads. Based upon morphology we identify other taxa at various locations within the gekkotan tree that are promising candidates for the expression of the early phases of adhesively-assisted locomotion. Investigation of functionally transitional forms will be valuable for enhancing our understanding of what is necessary and sufficient for the transition to adhesively-assisted locomotion, and for those whose objectives are to develop simulacra of the gekkotan adhesive system for biotechnological applications.

scholarly journals Direct mechanics assessment of elastic symmetries and properties of trabecular bone architecture

1996 ◽  
Vol 29 (12) ◽  
pp. 1653-1657 ◽  
Author(s):  
B. Van Rietbergen ◽  
A. Odgaard ◽  
J. Kabel ◽  
R. Huiskes
Keyword(s):  
Trabecular Bone ◽  
Bone Architecture ◽  
Trabecular Bone Architecture ◽  
Elastic Symmetries
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