135 research outputs found
Hydraulic conductivity of peat in Western Siberia
The paper aims at estimating hydraulic conductivity of peat. It is a complicated process since peat has some unique properties that are not typical for mineral soils. Other difficulties involve the lack of elaborated procedure for laboratory testing and data processing, high sensitivity of peat soils to external and internal factors; which leads to considerable fluctuation in peat hydraulic conductivity values. The specific properties of hydraulic conductivity in peat soils are proved by numerous experimental data. The article also provides the permeability values for the most typical peat species in Western Siberia. The obtained data allow forecasting peat soil response to the development of peatlands
Ignition and reaction mechanism of Co-Al and Nb-Al intermetallic compounds prepared by combustion synthesis
The ignition and propagation mechanism of the self-propagating high-temperature synthesis of several cobalt and niobium aluminides was investigated. Two propagation mechanisms were identified depending on the stoichiometry of the starting mixture. Al-rich compositions propagate through a dissolution-precipitation mechanism while Al-poor mixtures require solid state diffusion. The ignition temperatures were measured by means of microthermocouples in quasi-adiabatic conditions through experiments carried out in thermal explosion mode. Ignition temperatures were found to be characteristic of each system and to depend strongly on reactants particle size. Ignition energies for all compositions were evaluated through a mathematical model
Yamanaka Factors in the Budding Tunicate Botryllus schlosseri Show a Shared Spatio-Temporal Expression Pattern in Chordates
In vertebrates, the four transcription factors Sox2, c-Myc, Pou5f1 and Klf4 are involved in the differentiation of several tissues during vertebrate embryogenesis; moreover, they are normally co-expressed in embryonic stem cells and play roles in pluripotency, self-renewal, and maintenance of the undifferentiated state in adult cells. The in vitro forced co-expression of these factors, named Yamanaka factors (YFs), induces pluripotency in human or mouse fibroblasts. Botryllus schlosseri is a colonial tunicate undergoing continuous stem cell-mediated asexual development, providing a valuable model system for the study of pluripotency in the closest living relatives of vertebrates. In this study, we identified B. schlosseri orthologs of human Sox2 and c-Myc genes, as well as the closest homologs of the vertebrate-specific Pou5f1 gene, through an in-depth evolutionary analysis of the YF gene families in tunicates and other deuterostomes. Then, we studied the expression of these genes during the asexual cycle of B. schlosseri using in situ hybridization in order to investigate their possible involvement in tissue differentiation and in pluripotency maintenance. Our results show a shared spatio-temporal expression pattern consistent with the reported functions of these genes in invertebrate and vertebrate embryogenesis. Moreover, Myc, SoxB1 and Pou3 were expressed in candidate stem cells residing in their niches, while Pou2 was found expressed exclusively in the immature previtellogenic oocytes, both in gonads and circulating in the colonial vascular system. Our data suggest that Myc, SoxB1 and Pou3 may be individually involved in the differentiation of the same territories seen in other chordates, and that, together, they may play a role in stemness even in this colonial ascidian
Reply Platelet Reactivity Is Preferred Over Genotyping in Monitoring Efficacy of Antiplatelet Therapy
Variant on chromosome 9p is associated with left ventricular mass: results from two cohorts of essential hypertensive individuals
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Contribution to the knowledge of the vascular flora of Miniera di Murlo area (southern Tuscany, Italy)
Mutations impairing GSK3-mediated MAF phosphorylation cause cataract, deafness, intellectual disability, seizures, and a down syndrome-like facies
Transcription factors operate in developmental processes to mediate inductive events and cell competence, and perturbation of their function or regulation can dramatically affect morphogenesis, organogenesis, and growth. We report that a narrow spectrum of amino-acid substitutions within the transactivation domain of the v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog (MAF), a leucine zipper-containing transcription factor of the AP1 superfamily, profoundly affect development. Seven different de novo missense mutations involving conserved residues of the four GSK3 phosphorylation motifs were identified in eight unrelated individuals. The distinctive clinical phenotype, for which we propose the eponym Aymé-Gripp syndrome, is not limited to lens and eye defects as previously reported for MAF/Maf loss of function but includes sensorineural deafness, intellectual disability, seizures, brachycephaly, distinctive flat facial appearance, skeletal anomalies, mammary gland hypoplasia, and reduced growth. Disease-causing mutations were demonstrated to impair proper MAF phosphorylation, ubiquitination and proteasomal degradation, perturbed gene expression in primary skin fibroblasts, and induced neurodevelopmental defects in an in vivo model. Our findings nosologically and clinically delineate a previously poorly understood recognizable multisystem disorder, provide evidence for MAF governing a wider range of developmental programs than previously appreciated, and describe a novel instance of protein dosage effect severely perturbing developmen
Stem Cells and Innate Immunity in Aquatic Invertebrates: Bridging Two Seemingly Disparate Disciplines for New Discoveries in Biology
The scopes related to the interplay between stem cells and the immune system are broad and range from the basic understanding of organism's physiology and ecology to translational studies, further contributing to (eco)toxicology, biotechnology, and medicine as well as regulatory and ethical aspects. Stem cells originate immune cells through hematopoiesis, and the interplay between the two cell types is required in processes like regeneration. In addition, stem and immune cell anomalies directly affect the organism's functions, its ability to cope with environmental changes and, indirectly, its role in ecosystem services. However, stem cells and immune cells continue to be considered parts of two branches of biological research with few interconnections between them. This review aims to bridge these two seemingly disparate disciplines towards much more integrative and transformative approaches with examples deriving mainly from aquatic invertebrates. We discuss the current understanding of cross-disciplinary collaborative and emerging issues, raising novel hypotheses and comments. We also discuss the problems and perspectives of the two disciplines and how to integrate their conceptual frameworks to address basic equations in biology in a new, innovative way
Una complessa eredità: ricordando Fabrizio Frasnedi (1944-2015)
Il volume raccoglie una serie di contributi in ricordo di Fabrizio Frasnedi a cinque anni dalla sua scomparsa.
Interventi di Gian Mario Anselmi, Bruno Capaci, Maria Rosaria Catino, Guido Conti, Cristiana De Santis, Yahis Martari, Chiara Panzieri, Michele Prandi, Rocco Ronchi, Alberto Sebastiani, Matteo Vial
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