1,720,997 research outputs found
ESPERIENZE DI CHIMICA ANALITICA FORENSE NELL’AMBITO DEL PIANO LAUREE SCIENTIFICHE
No full textL’orientamento negli studi è di fondamentale importanza per la felicità personale e collettiva: non trovare la propria strada negli studi e di conseguenza nel lavoro può causare insoddisfazione, e può impedire di dare il proprio meglio a sé stessi ed alla società di cui si fa parte. Risulta quindi determinante ogni azione che permetta ad un adolescente di comprendere quali siano i propri talenti, in modo da poterli spendere con la massima efficienza ed efficacia possibili.
In questo lavoro vengono presentate le attività di orientamento svolte nell’ambito del Progetto/Piano Lauree Scientifiche dal 2005 al 2014. L’attività ha riguardato intere classi di scuole superiori, ed ha coinvolto 3732 alunni suddivisi in 204 classi di 40 scuole diverse, accompagnati da 112 insegnanti diversi; essa si proponeva un obiettivo di orientamento all’Università in generale ed alla Chimica in particolare.
L’orientamento generale è stato perseguito mediante una lezione nella quale si spiegava agli alunni quale sia la missione degli Atenei, come sia strutturato l’Ateneo di Bologna e quali criteri si possano adottare per entrare consapevolmente nella complessa e ricca struttura accademica, diventando matricole motivate e di talento.
L’orientamento alla Chimica è stato perseguito facendo entrare gli alunni dentro questa disciplina, vivendo in prima persona la giornata-tipo dello studente di Chimica dentro il Dipartimento di Chimica Ciamician: la lezione teorica in aula, l’esercitazione nel laboratorio chimico, l’elaborazione dei dati nel laboratorio informatico, la stesura di una relazione concisa ma esauriente; sono i vari aspetti del lavoro dello scienziato: studiare, sperimentare, elaborare e comunicare. Il tutto rigorosamente scientifico - anche se semplificato per poter essere compreso da alunni di scuola superiore - ma soprattutto divertente! Il tema della Chimica Forense nell’ambito delle “Indagini di Polizia Scientifica” è accattivante, quindi cattura l’attenzione e permette di superare l’iniziale smarrimento che può essere generato dalla rigorosa oggettività della scienza e dall’astrazione dei metodi matematici e statistici che essa usa
Field-Flow Fractionation: a physical method of separation in the macromolecular and supramolecular field
No full textThallium: A Polluting Metal of New Generation. Its Voltammetric Determination in Herbal Medicines in Presence of Metal Interferences
Full text linkThe present paper reports a new application: the voltammetric determination in herbal medicines of ultra-trace thallium(I), in the presence of lead(II), tin(II) and antimony(III) as interfering metals, by square wave anodic stripping voltammetry (SWASV). A conventional three-electrodes voltammetric cell was employed with a stationary hanging mercury drop electrode (HMDE) as working electrode and a platinum electrode and an Ag|AgCl|KClsatd. electrode as auxiliary and reference electrodes, respectively. The supporting electrolyte was 0.5 mol L−1 ammonium citrate buffer pH 6.5 + 7.3·10−3 mol L−1 EDTA-Na2. The analytical procedure was verified by the analysis of the standard reference materials: spinach Leaves NIST-SRM 1570a and tomato leaves NIST-SRM 1573a from National Institute of Standards and Technology. Precision and trueness, expressed as relative standard deviation and relative error, respectively, were generally lower than 7% in all cases. Once set up on the standard reference materials, the analytical procedure was transferred and applied to herbal medicines samples—Taraxacun officinale weber, Eucalyptus globulus and Harpagophytum procumbens DC—sold on the market. A critical comparison with spectroscopic measurements is also discussed
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
Hollow-fiber flow field-flow fractionation and multi-angle light scattering as a new analytical solution for quality control in pharmaceutical nanotechnology
No full textThe rapid development of nanoproducts in pharmaceutical field highlights the need for robust analytical methods to ensure their quality and stability. Nanoparticles of different nature and composition (NPs) are employed for many purposes, such as the improvement of drug solubility/bioavailability and the controlled delivery of drugs. Among NPs features, particle size distribution (PSD) plays a fundamental role in determining NPs properties. Nevertheless the high development of different NPs, authorities such as the FDA and the European Union highlight the lack of robust characterization methods and quality control for nanomaterials.
Among the techniques for the size-characterization of particles, Field-Flow Fractionation (FFF) represents a competitive choice: due to the absence of a stationary phase, the separation mechanism is gentle with total maintenance of the native properties of the analytes. In this paper the microcolumn variant of FFF, the Hollow-Fiber Flow FFF (HF5), is coupled on-line with Multi-Angle Light Scattering (MALS) for the development of methods for the characterization of NPs as quality control in new pharmaceutical field. The HF5-MALS was applied to the size characterization in different preservation conditions of silver polyvinylpyrrolidone-stabilized NPs (AgPVP) used for their antimicrobial activity. The ratio of gyration and hydrodynamic radii of AgPVP was evaluated for fresh and aged NPs, suggesting in this case aggregation rearrangement. The influence of different PVP coating and dilution factor was also studied. Finally the metal ion release was determined in relationship to these shape modifications. The HF5-MALS method is robust and reproducible and it can be considered as an important tool for the development of analytical platform for quality control of NPs
Gelatin Porous Scaffolds as Delivery Systems of Calcium Alendronate
No full textThe systemic administration of bisphosphonates (BPs) for the treatment of metabolic diseases characterized by abnormal bone loss suffers from several adverse side effects, which can be reduced by implementation of alternative modes of administration. In this work, glutaraldehyde cross-linked gelatin scaffolds are proposed as delivery systems of calcium alendronate monohydrate (CaAL•H2O). The 3D highly porous scaffolds display a relevant interconnected porosity (>94%), independently from CaAL•H2O content (0, 3, and 6 wt%). At variance, pore size varies with composition. The relative increase of the number of smaller pores on increasing BP content is in agreement with the parallel significant increase of the compressive modulus and collapse strength. The scaffolds exhibit a sustained CaAL•H2O release profile, and a significant amount of the drug is retained in the scaffolds even after 14 d. In vitro tests are carried out using cocultures of osteoblast (OB) and osteoclast (OC). The evaluation of differentiation markers is performed both on the supernatants of cell culture and by means of quantitative polymerase chain reaction. The results indicate that BP containing scaffolds support osteoblast proliferation and differentiation, whereas they inhibit osteoclast viability and activity, displaying a promising beneficial role on bone repair processes. (Figure presented.)
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