97 research outputs found
Influence of saccharides on the dosimetric properties of PVA-GTA Fricke gels
No full textThe Fricke gels (FG) composition has been modified over the years in order to improve their dosimetric characteristic for spatial dose evaluation in radiotherapy. Some problems have limited the clinical use of FG and still represent significant challenges for the scientific community working in the field of gel dosimetry. With this study, the effects of saccharides like sucrose and glucose on the dosimetric properties of Fricke gels based on poly(vinyl-alcohol) (PVA) as gelling agent and glutaraldehyde (GTA) as cross-linker have been tested. The dose-response curves of PVA-GTA Fricke gel dosimeters prepared using different sucrose and glucose concentrations were investigated by optical absorbance measurements. The shape of the optical absorbance spectra of the gel dosimeters in the wavelength interval 360–720 nm have shown a slight dependence on the saccharides concentration and varied with the absorbed dose. The results demonstrated that the use of different concentrations of sucrose and glucose does not produce significant dosimetric consequences in the interval of linearity (0–16 Gy) of the dose-response curve of the PVA-GTA Fricke gel dosimeters
Gel Dosimetry
No full textThe purpose of radiation therapy (RT) is to cover tumor tissue homogeneously with a planned dose while minimizing the dose to the surrounding healthy tissue [...
UNNATURAL AMINO ACIDS AS SYNTHETIC TOOLS FOR THE PREPARATION OF COMPLEX MOLECULAR ARCHITECTURES
No full textSelf-assembly is the process by which an organized structure spontaneously is formed from individual components, as a result of specific, local interactions between the units.
In recent years, peptide-based self-assembled structures have emerged as a powerful approach for developing soft and hybrid materials due to their biocompatibility, biodegradability and easily tuning properties of the final structure.
The introduction of non-natural amino acids into a peptide backbone imparts additional features such as reduced conformational flexibility, high tendency to adopt a well-defined secondary structure and enhanced metabolic stability.
My PhD thesis is focused on the synthesis of ultrashort peptides containing non-natural scaffolds which are able to self-assemble and form supramolecular structures. The thesis is divided into three chapters, each one reports a project regarding the synthesis and chemical characterization of scaffolds which can be inserted in peptide sequences and exploited for developing soft or hybrid materials by self-assembly.
The first chapter concerns the supramolecular assemblies of spherical shape obtained from different peptides containing Cα,α-tetrasubstituted amino acids. Firstly, the results on a pentapeptide containing norbornene amino acid is reported (work published on RSC Advances). Then, the simplification of this structure is reported until obtaining a pentapeptide containing Ala-Aib motif only. The ability of this peptide to form aggregates that can be exploited for the encapsulation of hydrophobic molecules has been studied. As a proof of concept the well-known curcumin molecule has been used. The interaction of the drug molecules with peptide aggregates has been studied using the absorption and the intrinsic fluorescence emission of curcumin.
Starting from this peptide, it is also possible to develop peptide-ligands which stabilize gold nanoparticles in aqueous solution. The stability of nanoparticles has been studied using DLS and UV-vis spectroscopy.
The second chapter reports on a β2,3-diarylamino acid, developed in our group, which is non-natural analogous of the dipeptide Phe-Phe. This amino acid has been used to develop hybrid antifouling film which has been characterized using different techniques (contact angles values, QCM-D). The third chapter concerns the preparation of an original heterocyclic scaffold to be inserted into a peptide backbone and its exploitation for the formation of soft materials by the way of an “induced assembly”. The electrospinning technique allowed the formation of electrospun nanofibers from these non-natural peptide-based small molecules and their characterization with several techniques (SEM, AFM, FT-IR, Raman) is reported
Ancognatha veliae Pardo-Locarno, Gonzalez & Montoya-Lerma, 2006, sp. nov.
No full text<i>Ancognatha veliae</i> sp. nov. Pardo­Locarno, Gonzalez, and Montoya­Lerma <p> <b>Holotype:</b> Cerro del Inglés (The English Hill), 2400 m.a.s.l., Western Cordillera, San José del Palmar (4o45’47”N; 76o13’35”W), Chocó, Colombia, Collector: P. Silverstone, January 1987, (Botanical Expedition). Preserved at the Entomology Museum of the Universidad del Valle (MEUV), Cali, Colombia (Curator, C. E. Posso).</p> <p> <b>Diagnosis</b>: This species is most similar to <i>A. matilei</i> (Fig. 1, 2 b, 3b) and can be distinguished from this species by the following set of character states: clypeal apex elongate, truncate, with rounded angles; robust mandibles shorter than the clypeus; femora elongate, protruding laterally from the body in dorsal view; elytra densely punctured with transversal grooves; protarsomere 5 with interior border smooth; first abdominal sternite hidden by the metacoxae; pygidium with apical marginal bead simple; dorsum (except for head) shiny; aedeagus with parameres relatively short, broad at base, with apex truncate; parameres with lateral excavation conspicuous, posteriorly limited by a thin carina protruding from the caudal border (see Fig.3 a).</p> <p> <b>Holotype description. Male:</b> Body length 32 mm, body robust, shiny (Fig. 1). <i>Colour:</i> dorsally yellowish­brown with dark brown head and brown spots on each side of pronotum and elytral humerus (Fig. 1). Abdominal sternites dark yellowish­brown. <i>Head</i>: almost as wide as long, base broad, apex abruptly narrowed into a long clypeus with irregularly convex border. Clypeal apex quadrangular with rounded angles. Clypeus and frons densely punctate, punctures on the clypeus larger but reduced in size basally, frons grooved between eyes. Diameter of eyes approximately 0.25 times that of cephalic width; eyes surrounded by dark, circumocular depression. Frons unarmed; frontoclypeal suture grooved and slightly melanised, grooves deeper and sinuate near antennal insertion. Ocular canthus short, narrow, punctured, grooved. Mandibles protruding laterally from clypeus in dorsal view; long, but not reaching clypeal apex; base triangular (in dorsal view); apex acute, reflexed. Mentum emarginate apically; basal two­thirds strongly convex, bulky, with two convergent rows of long, stout setae. <i>Thorax</i>. Pronotum with disc strongly convex, almost rounded; surface punctate with large, slightly grooved punctures surrounded by fine, sparse punctures. Diameter of the large punctures ranging from 1/5 to 1/ 6 mm being 3 to 4 times as wide as fine punctures. Pronotum rounded laterally with dark, emarginated border; apical angles obtuse; apical border sinuate, especially at lateral edge. Pronotum basal border slightly sinuate. Prosternal process slightly lower than that of anterior coxae, apex expanded in a rounded process, ridged and transverse; border pubescent with long, robust seta. Base of the prosternal process with distinct posterior projection. <i>Legs</i>. Legs robust (Fig. 1, 2 a); femora elongate, protruding beyond body in dorsal view. Protibia robust, shiny, quadridentate, dorsally with row of setae; tridentate, second tooth wide, third smaller, situated at distal third; internal border carinate with row of setae, carina conspicuous proximally; protibia ventrally convex with longitudinal, pubescent carina extending from base to beyond midpoint; tarsal insertion beginning at transversal carina near apex. Protarsus robust (2a), first tarsomere short, tarsal claws large; apex of tarsomere 1 scarcely distinguishable under apical border of the tibia; tarsomere 3 partially directed beneath; tarsomere 4 with large lateral projection directed inside; tarsomere 5 long, internal border without teeth, dorsally microsurcated. Protarsal claw as long as tarsomere 5, twice as long as first four tarsomeres combined; unguitractor plate (including setae) as long as the smaller claw on protarsus. Mesotibia with external border, transversal carina weakly defined, apical notch slightly depressed, apex dentate (in transverse section), setae robust. Metatibia in transverse section with dentate, rectangular apex, first tarsomere as long as second. <i>Abdomen</i>. Scutellum glabrous, wide, with small elytral ridge at each side; scutellum disc punctate as in pronotum but with darker borders. Elytra 1.24 times longer than wide; widened, expanded medially; glabrous, slightly convex, somewhat flattened, with double ridge of punctures; disc with transverse grooves. Elytral suture dark, carina or row of punctures absent. Epipleuron dark with doubled border starting at humeral angle, continuing almost to posterior angle. First abdominal sternite almost hidden by metacoxa. Last abdominal segment with a row of thin setae bordering the anal opening. Pygidium shiny, brown, convex; with defined border elevated or superficial apically, diffuse basally; central disk slightly wrinkled with vertical grooves directed towards apex; lateral angles slightly wrinkled with micropunctures and few larger punctures; surface with narrow arch near apical border extending to lateral angles. Propygidium with sparse, short pubescence. <i>Aedeagus</i>: Relatively small compared with size and robustness of body. Parameres short, basally widened, apex truncated, lateral excavation pronounced but posteriorly limited by carina protruding from basal border (Fig. 3 a).</p> <p> <b>Paratype</b>: 1 male, same data as holotype. Paratype differs from holotype in the following respects: body length 34 mm. Head with transverse, melanised band between eyes; eyes bordered by melanised band; elytra 1.25 times longer than width. Female: unknown</p> <p> <b>Etymology.</b> This species is dedicated to Mrs. Velia Yolanda Locarno, the mother of Luis Carlos Pardo­Locarno, the first author of this paper.</p> <p> <b>Habitat.</b> Tropical rain forest in Chocó is located at approximately 2400 m of altitude. The area corresponds to the Choco biogeographical region, one of the most biodiverse areas on the earth (Armbrecht <i>et al</i>. 2001).</p> <p> <b> Key to males of <i>Ancognatha</i> with elongate clypeus and mandibles</b> . Endrödi’s (1985) key has been modified below to accommodate <i>A. veliae</i> and <i>A. matilei</i>. The later species was described by Dechambre (2000).</p> <p>6 Mandibles as long as clypeus. Pronotum with large and fine punctures. Diameter of the large punctures ranging from 1/5 to 1/ 6 mm being 3 to 4 times as wide as the fine punctures. Protarsus elongate, protruding laterally beyond elytron in dorsal view.... 6a</p> <p> 6´Mandibles shorter than clypeus. Pronotum with small, sparse punctures. Protarsus not elongate............................................................................................. <i>A. horrida</i> Endrodi</p> <p> 6a Dorsum with black, yellow, reddish­yellow colouration; rarely with pronotum and elytra almost entirely black. Clypeal width twice that of length. Total length 15–20 mm <i>......................................................................................................... A. jamesoni</i> Murray</p> <p>6a´Dorsum yellow with only one small, elongate, black spot on humerus. Clypeal width less than twice that of length. Total length greater than 30 mm.................................. 6b</p> <p> 6b Clypeus rounded, mandibles as long as clypeus. Protarsomere 5 with internal edge dentate. Elytra not shiny, 1.5 times longer than wide. Pygidial ridge well defined apically <i>...................................................................................................... A. matilei</i> Dechambre</p> <p> 6b´Clypeus truncate, mandibles shorter than clypeus. Protarsomere 5 with internal edge not dentate. Elytra shiny, 1.25 times longer than wide. Pygidial ridge shallow apically <i>................................................. A</i>. <i>veliae</i> Pardo­Locarno, Gonzalez, & Montoya­Lerma</p>Published as part of <i>Pardo-Locarno, Luis Carlos, Gonzalez, Ranulfo & Montoya-Lerma, James, 2006, Ancognatha Erichson (Coleoptera: Scarabaeidae: Dynastinae) from Colombia, pp. 63-68 in Zootaxa 1139</i> on pages 64-67, DOI: <a href="http://zenodo.org/record/172034">10.5281/zenodo.172034</a>
Flipped classroom per la formazione insegnanti: una ricerca sulla percezione degli studenti
No full textViene presentata un’esperienza didattica in cui è stato adottato l’approccio flipped classroom, integrato con una progettazione a ritroso, della quale si riportano i risultati di ricerca sulla percezione degli studenti. Il contesto di sperimen- tazione è stato un corso di geometria e didattica della geo- metria, rientrante nella formazione iniziale di futuri insegnan- ti di scuola elementare offerta dal Dipartimento formazione
e apprendimento della Scuola universitaria professionale della Svizzera italiana (SUPSI), che ha sede a Locarno. Dai risul-
tati emergono percezioni positive da parte degli studenti dell’ap- proccio flipped classroom, rispetto alla sua efficacia, al confronto con la metodologia usuale e agli aspetti apprezzati o considerati da migliorare dell’intero corso. Da tali risultati sono state inoltre ricavate considerazioni operative sull’imple- mentazione dell’approccio flipped classroom in ambito terziario. La ricerca si inserisce in un più ampio progetto di ri- cerca dal titolo Flipped classroom come approccio per lo sviluppo di competenze, che ha coinvolto diversi dipartimenti della SUPSI, in collaborazione con la Fernfachhochschule Schweiz di Briga e l’Università di Torino.In this article we present a teaching/learning experience based on the flipped classroom approach, integrat- ed with a backward design. The results about students’ perception are shown. The experimentation context was a Geometry and Geometry Education course, belonging
to the initial training for primary school teachers, offered by the Dipartimento formazione e apprendimento of the
Scuola Universitaria Professionale della Svizzera Italiana (SUPSI), based in Locarno. The results show a positive students’ perception of the flipped classroom approach, with respect to its effectiveness, its comparison with the usual methodology and the appreciated aspects and the improvable ones throughout the whole course. We also deduce prac-
tical considerations about the implementation of the flipped classroom approach in the tertiary education. The research
is part of a broader research project entitled Flipped classroom as a competence based approach, involving several SUPSI departments, and in collaboration with the Fernfachhochschu- le Schweiz of Brig and the University of Turin
Cultured Human Meat Acceptability: From Inviolability of Human Body to Prevention of Induced Human Meat Craving
No full textCultured meat is a lab grown product that aims to tackle the cravings of omnivores who struggle to switch to a plant-based diet, while still being friendly to animals and the environment. Possibly, in time, the curiosity to apply this technology towards human meat production will emerge. However, when presented with the thought of eating cultured human meat potential consumers’ reaction greatly varies from pure disgust to indifference to excitement. This instinctive response indicates a lack of preformed judgements towards the topic. Without a clear vision on the possibility of cultured human meat, scattered and uncertain regulations will fail to uphold paramount moral values. The risk is that we would either dig into this option out of excitement, or ban it without convincing motivations. The ethical theories of deontology and consequentialism can be followed to investigate this divisive issue. With an evaluation based on disgust I argue that the deontological perspective is mostly concerned with values of identity and humanness, while with a chain-reaction reasoning I argue that consequentialism would be concerned with health safety, privacy and equality. I conclude that cultured human meat is not acceptable.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ImPhys/Brinks grou
Dosimetric characterization of double network Fricke hydrogel based on PVA-GTA and phenylalanine peptide derivative
No full textA double network hydrogel based on Poly(vinyl-alcohol) (PVA) cross-linked with Glutaraldehyde (GTA) was recently developed by using self-assembling phenylalanine (Phe) peptide derivative (Fmoc-Phe-Phe-OMe), with the aim to improve the mechanical-elastic properties of PVA-GTA hydrogels. In this study, a characterization of the properties of Xylenol Orange based Fricke gel dosimeters obtained by infusing a Fricke solution into the double network hydrogel was performed. The gel dosimeters were irradiated with 6 MV and 15 MV X-rays produced by a medical linear accelerator and investigated by means optical absorbance measurements. The double network hydrogel formulation maintained a satisfactory level of radiological water-equivalence within the investigated radiotherapy range. Fricke gel dosimeters prepared with such network kept the desired properties of independence of the response of the dose rate and energy in the investigated intervals. Furthermore, the addition of self-assembling Phe peptide derivative proved not avoid the motion of radio-inducted ferric ions into the hydrogel, probably maintaining the main characteristics of the standard, no Phe peptide infused, formulation. The time course of formation of the optical response after the irradiation was observed to be similar to what previously measured in traditional PVA-GTA Fricke gel dosimeters, while a decrease of the sensitivity to radiation dose of the order of 30% was found. The extent of the decrease does not seem such as to impair the use of these dosimeters for evaluation of doses typical of radiation therapy applications. The overall dosimetric properties, coupled with the mechanical-elastic characteristics of the double network hydrogel, pave theway to the development of phantoms able both to mimic the deformation of organs possibly occurring during radiotherapy treatments and at the same time to assess the 3D dose distribution within such volumes
Highly active Pd–ZrO2 electrodes for hydrogen evolution reaction
No full textHere we discuss the use of a family of electrode materials, which exhibit specific electrocatalytic activity for hydrogen evolution reaction and hydrogen oxidation reaction. These composite materials show extended lifetime, also being very cheap in comparison with pure palladium. We specifically focus on composite electrodes formed by Pd and ZrO2, a ceramic oxide compatible with human tissues, whose role is to enhance the electroactivity of classic platinum group metals, thus significantly reducing the catalyst load. To carefully control the electrocatalyst composition and morphology, the electrodes are prepared by ion beam sputtering deposition onto fluorine-doped tin oxide supports, thus obtaining ordered layers of ceramic and electrocatalyst. The outcomes point to the synergistic effects between the precious metal catalyst and ceramic diluent not only in terms of the chemical stability of the layer but also of the electrochemical activity of the composite material
- …
