1,720,966 research outputs found
CATALITIC ACTIVITY OF IMMOBILIZED FUMARASE
No full textIn order to evaluate the influence of the immobilization techniques of fumarase on its immobilization yield and on its
catalytic activity, it was covalently bonded to the surface of polymers (consisting of suitably functionalized ethylene–vinyl
alcohol copolymers and functionalized poly(acrylamides), and physically entrapped into cross-linked poly(acrylamide) gels.
The kinetic parameters of the hydration reaction of fumarate to l-malate were obtained by determining the UV absorbance
variation of the fumarate double bond at 290 nm.
When the enzyme is covalently bonded, both activity and stability of the enzymatic preparations are low; however, when fumarase is bonded to ethylene–vinyl alcohol copolymers by less denaturating and more spacing coupling agents (as glutaraldehyde), a better residual enzyme activity was obtained, and it was seen that this latter depended on the amount of bonded enzyme. Also the influence of the hydrophilicity of the polymer matrix on the amount of bonded enzyme and on its activity was evaluated. Satisfactory results were obtained by physical entrapment of the enzyme into poly(acrylamide) gel, with quantitative immobilization yields, a rather good enzyme activity (η = 38 ± 5%), and a constant catalytic activity, under operative conditions, for several days.
The inhibiting effect of methanol concentrations up to 20% (v/v), in the reaction medium, was also evaluated for the
different immobilized enzyme preparation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Buckypaper (bp) as absorbable adhesive for surgical application in abdominal wall defects
No full textTOPICS: Biotecnologia ed innovazioni tecnologiche. Le proposte italiane nella ricerca.
BUCKYPAPER (BP) AS ABSORBABLE ADHESIVE FOR SURGICAL APPLICATION IN ABDOMINAL WALL DEFECTS
Massimo Chiaretti(1), Andrea Martinelli(2), Giovanna Angela Carru(3), Emanuela D’Amore(4), Alessandra Maria Chiaretti(5), Fabio Faiola(6), Paola Consentino(7), Eleonora Valente(8), Annalisa Italia Chiaretti(1)
(1)Department of General Surgery “Paride Stefanini”, Sapienza University of Rome, Viale del Policlinico 155, Rome, 00161 (Italy)
(2)Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, Rome, 00185 (Italy)
(3)Policlinico Umberto I Hospital, Sapienza University of Rome, Viale del Policlinico 155, 00161 - Rome (Italy)
(4)National Health Institute, Viale Regina Elena 299, 00161 - Rome (Italy)
(5) Istitute of Genetic Risearch G. Salvatore, “Consorzio Interuniversitario di Scienze e Tecnologie Genetiche Biogem”;
(6)Department of Molecular Medicine, Sapienza University of Rome, Viale Regina Elena 324, Rome, 00161 (Italy)
(7)Appialab Srl V. Latina, 286 00179 Rome (+39) 067825111www.appialab.it
(8)Policlinico Agostino Gemelli, Università Cattolica del Sacro Cuore, Roma
E-mail: [email protected]
Keywords: buckypaper, BP, MWCNTs, medical application, abdominal wall defects surgery, wet adhesion, absorbable adhesive device.
Introduction: One of the main problems related to the abdominal prosthetic surgery is the mesh fixation. Mesh displacement, improper and blind application of metal tacks and staples in laparoscopy surgery are the main causes of complications such as seroma, postoperative pain and recurrence[6-9]. The use of fibrin glue between the prosthesis and the damaged tissue, although it has become a well-established surgical procedure, represents a possible risk associated to the transmission of unknown diseases related to the use of human blood-derived materials [9]. Moreover, it was observed that an increased incidence of postoperative seroma is associated to the use of fibrin glue for mesh fixation[10]. Surfaces able to adhere promptly and strongly on wet biological tissue may represent an effective alternative to the conventional prosthesis fixation methods. This study realized on animal model proposes the application of the nature inspired micro- or nano-patterned adhesive surfaces, by exploiting the scaling effect, according to which the adhesion strength can be enhanced through the reduction of interface adhesive contact size[12]. We experimented evidences on the potential applicability on biological tissue of the BP as an adhesive tape, a self-standing felt composed of entangled multi-walled carbon nanotubes. In vitro bench surgery, mechanical peeling, and shear adhesion tests, and In vivo tests were tested with prosthetic meshes[2,3,4,10]. BP shows a stronger adhesion, but only on wet tissues[12] much better than both self-gripping commercial mesh and fibrin-glue non-gripping meshes and fabrics. Prompted by these results, we implanted BP in pigs, to assess BP effectiveness as adhesive absorbable prosthetic device and its biocompatibility. After 90 days from the operation we observed no pig behavioral alteration. BP samples preserved their position in the implantation site and mechanical adhesion was enhanced, both in laparoscopy and laparotomic procedure. Materials and Methods. Operated 30 Lantrace female 40-50 Kg pigs, 15 in laparoscopic procedure and 15 in laparotomic procedure. Operated and control subjects did not show mortality or morbidity, no significant neurovegetative or behavioral differences. Results and Discussion. Body weight monitoring graph do not showed any significant difference between BP and control group. The Hematoxilin and Eeosin stained implant section reported BP surface fragmentation that shows the formation of a capsule of loose fibrous tissue, consisting of fibroblasts and collagen fibers, indicative of a weak inflammation reaction. The necroscopy examination showed that the implanted BP favors a cicatrisation process, the mesh appearing wrapped in the inflammatory reaction. Conclusions: a strong BP adhesion on wet biological tissue was measured. In view of a possible application as adhesive absorbable tape in surgery, preliminary in vivo experiments were carried out on big pig model. Necroscopical and histological investigations enlighten that as 90 days after the implantation the BP elicits minimal adverse tissue response. Nanometric carbon nanotube aggregates were phagocytised by macrophages and observed in Bowman's urinary space. The assessment of the BP debris, possible toxicity or confinement or metabolism and accumulation or excretion mechanism needs further studies.
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12. A. Martinelli, GA. Carru, L.D'Ilario, F. Caprioli, M. Chiaretti, F. Crisante, I. Francolini, and A. Piozzi. ACS Appl. Mater. Interfaces, DOI:10.1021/am400543s • Publication Date (Web): 18 Apr 2013, http://pubs.acs.org on April 19, 201
ENERGY METABOLISM AS POSSIBLE STIMULUS OF GROWTH HORMONE RESPONSE TO HIGH INTENSITY EXERCISE.
No full textDispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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