322,907 research outputs found
The inward current activated by bradikinin in Balb-c 3T3 fibroblasts and its relationship to fibroblast growth factor activated currents
No full textHydrogen sulfide as regulator of calcium channels
No full textAn increasing body of evidence suggests the involvement of hydrogen sulfide (H(2)S) in different physiological and pathological processes. Similarly to the other gasotransmitters nitric oxide (NO) and carbon monoxide (CO), this bioactive compound is rapidly diffusible through the biological membranes and acts in a paracrine fashion. Despite the large amount of biological actions observed in vitro and in vivo upon stimulation with H(2)S donors, as well as by interfering with its synthesis, the molecular targets and mechanisms through which it exerts its intracellular effects are only partially known. A number of proteins are covalently modified by H(2)S through sulfhydration of specific cysteine residues. However, only in few cases their identity has been discovered and the functional role of this post-translational modification needs to be investigated in more detail. Great attention has been devoted to potassium channels, particularly K(ATP), as they are considered key mediators of H(2)S-induced effects, and their sulfhydration has been clearly demonstrated. Recently, different authors reported the ability of H(2)S to interfere with calcium homeostasis in neurons, cardiomyocytes and endothelial cells. Since calcium signaling is involved in all cell processes, these observations attracted increasing attention from basic biology and medicine. Although some effects of H(2)S on calcium signals can be ascribed to K(ATP) modulation, there is growing consensus about the existence of other targets for the gasotransmitter. Some of them are Ca(2+)-permeable channels. In this review we discuss the state of the art in this specific field, providing an updated report of H(2)S interaction with Ca(2+) channels and its functional outcomes
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Role of surface finishing on the in vitro biological properties of a silicon nitride-titanium nitride (Si3N4-TiN) composite
No full textSilicon nitride (Si3N4) has been introduced clinically as an orthopedic biomaterial for interbody fusion devices and in joint replacements. However, the production of complex shapes through conventional mechanical machining is difficult and expensive and limits interesting applications. Thus, several electrically conductive reinforcements to the Si3N4 matrix, like TiN, have been proposed, generating composites suitable to be wrought by electrical discharge machining (EDM). In this study, Si3N4-TiN with high strength, low density, and good electric conductivity wrought by EDM was studied. The role of surface finishing was investigated comparing the interface generated during the EDM process to that resulting from further polishing. The different topographical features were assessed by electron microscopy, energy dispersive X-ray spectrometry, and profilometry. Surface wettability was also determined based on the measurement of the OCA of water and diiodomethane. The biological responses induced in MC3T3 cells, a widely diffused osteoblast model, were correlated with the surface pattern. The unpolished samples could promote better cell viability, with a more relevant effect on the cytoskeleton arrangement as highlighted by numerous cytoplasmic extensions and filopodia-like structures and the high number of focal adhesions, while MC3T3 cells grown on polished Si3N4-TiN specimens displayed a flat morphology. In addition, the unpolished Si3N4-TiN increased osteocalcin production and calcium deposition. Taken together, these data support the biocompatibility and in vitro osteogenic properties of the electroconductive Si3N4-TiN investigated. Further in vivo studies are required to explore the possible use of bone implants directly obtained by EDM
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