2,038 research outputs found
Una chiacchierata con Serena Sinigaglia
No full textNell\u27anno accademico 2011-2012, Serena Sinigaglia ha collaborato con la cattedra di Estetica e di Estetica dello Spettacolo alla realizzazione di un laboratorio teorico-pratico sulla figura di Ipazia d\u27Alessandria finalizzato alla messa in scena di testi elaborati dagli studenti. Intervista a Serena Sinigaglia realizzata da Alessia Gennari e Raffaella Colombo il 20 aprile 2012 nel foyer del Teatro Ringhiera
Convergences and divergences of thymus-and peripherally derived regulatory T cells in cancer
No full textThe expansion of regulatory T cells (Treg) is a common event characterizing the vast majority ofhuman and experimental tumors and it is now well established that Treg represent a crucial hurdle fora successful immunotherapy. Treg are currently classified, according to their origin, into thymus-derived Treg (tTreg) or peripherally induced Treg (pTreg) cells. Controversy exists over the prevalent mechanism accounting for Treg expansion in tumors, since both tTreg proliferation and de novo pTreg differentiation may occur. Since tTreg and pTreg are believed as preferentially self-specific or broadly directed to non-self and tumor-specific antigens, respectively, the balance between tTreg and pTregaccumulation may impact on the repertoire of antigen specificities recognized by Treg in tumors. The prevalence of tTreg or pTreg may also affect the outcome of immunotherapies based on tumor-antigen vaccination or Treg depletion. The mechanisms dictating pTreg induction or tTreg expansion/stability are a matter of intense investigation and the most recent results depict a complex landscape. Indeed, selected Treg subsets may display peculiar characteristics in terms of stability, suppressive function, and cytokine production, depending on microenvironmental signals. These features may be differentially distributed between pTreg and tTreg and may significantly affect the possibility of manipulating Treg in cancer therapy. We propose here that innovative immunotherapeutic strategies may be directed at diverting unstable/uncommitted Treg, mostly enriched in the pTreg pool, into tumor-specific effectors, while preserving systemic immune tolerance ensured by self-specific tTreg. © 2013 Burocchi, Colombo and Piconese
Coupling of a Copper Dye with a Copper Electrolyte: the Birth of Sustainable “Full-Copper” Dye-Sensitized Solar Cells
No full textTo have enough clean and low cost energy for the future is one of the world’s most important challenges. Since the discovery of Grätzel-type dye-sensitized solar cells (DSSCs) as a convenient way for harnessing the energy of the sun and converting it into electricity, there has been a lot of effort to improve the photo-conversion efficiency, trying to optimize the sensitizer and the redox mediators. Until recently, the most efficient DSSCs were based on ruthenium complexes as dye and the iodide/triiodide couple as redox mediator. However, ruthenium is one of the rarest and most expensive metal, and this is a drawback in the design of low-cost DSSCs. Photophysical, economic, and environmental considerations make copper(I) coordination compounds interesting alternatives to ruthenium dyes [1-2]. Besides, it was found that Cu-based mediators can outperform both iodine-based and Co-based electrolytes [2]. These observations were the springboard for the first “full-copper” DSSCs in which a copper(I) dye is coupled with a copper(I)/(II) electron shuttle, of great interest for the development of novel low cost and environmentally friendly DSSCs.
This presentation is on the birth of “full-copper” DSSCs. First, it will be shown how homoleptic and heteroleptic copper(I) dyes can be coupled with the common I–/I3– redox couple to prepare DSSCs with a good efficiency. Then, some examples of the use of homoleptic Cu(I)/(II) mediators, in combination with both ruthenium(II) dyes and organic dyes, will be given. Finally, the coupling of a copper dye with a copper electrolyte as a fascinating route for sustainable “full-copper” DSSCs will be presented.
[1] C. E. Housecroft, E. C. Constable, Chem. Soc. Rev. 2015, 44, 8386- 8398.
[2] M. Magni, P. Biagini, A. Colombo, C. Dragonetti, D. Roberto, A. Valore Coord. Chem. Rev. 2016, 322, 69-9
How do ‘family affairs’ affect firm’s stock price? An application on an exploratory case study
No full textHow do ‘family affairs’ affect firm’s stock price? An application on an exploratory case study
No full textOrbit design for future SpaceChip swarm missions in a planetary atmosphere
No full textThe effect of solar radiation pressure and atmospheric drag on the orbital dynamics of satellites-on-a-chip (SpaceChips) is exploited to design equatorial long-lived orbits about the oblate Earth. The orbit energy gain due to asymmetric solar radiation pressure, considering the Earth's shadow, is used to balance the energy loss due to atmospheric drag. Future missions for a swarm of SpaceChips are proposed, where a number of small devices are released from a conventional spacecraft to perform spatially distributed measurements of the conditions in the ionosphere and exosphere. It is shown that the orbit lifetime can be extended and indeed selected through solar radiation pressure and the end-of-life re-entry of the swarm can be ensured, by exploiting atmospheric drag
The interaction between calcium lignosulfonate and cement
No full textModern concrete applications intensify the need for highly-flowable concretes, which are at the same time durable and possess good mechanical properties. The addition of plasticizers to the concrete mix allows obtaining highly workable concretes maintaining low water-to-binder ratios, which is beneficial for compressive strength and durability.
However, the addition of plasticizer can cause retardation in the setting time of concrete, which limits the dosage of plasticizer usable in practice. In addition, incompatibility issues can exist between plasticizer and cement, possibly leading to higher LSs dosage needed to reach a given workability, severe setting retardation, rapid set, and sudden slump loss.
In this PhD thesis, a sugar-reduced softwood calcium lignosulfonate (LSs) was used as plasticizer. The LSs was used in pastes of two Portland cements with different chemical composition and specific surface area: a CEM I 52.5 N (ANL) and a CEM I 52.5 R (CX), as defined by the European Standard EN197-1:2011.
The first objective of this PhD thesis is to understand the mechanisms behind the interaction between lignosulfonate and cement. This is important to foresee the effects of the plasticizer on workability and setting time of cement, avoiding any possible incompatibility issue.
In light of the mechanisms of consumption of LSs by the cement paste, the impact of the LSs on the rheology and setting time of the cement paste was studied. This represented the second objective of this PhD thesis.
The investigations in this first phase of the PhD project brought in light that the amount and morphology of the ettringite formed in the cement paste played a major role in the rheological and setting behaviour of the cement pastes investigated. For this reason, the third objective of this PhD thesis was to investigate more deeply the impact of the LSs on ettringite.
The investigations undertaken in this PhD thesis highlighted that, when added immediately with the mixing water (immediate addition, IA), the LSs led to an increased formation of ettringite after 30 minutes of hydration, especially for the high-C3A cement (CX). No increase in the ettringite formed was detected when the LSs was added after 10 minutes of hydration (delayed addition, DA). The ettringite had cubic or rectangular prism shape and length between 0.1 and 0.4 µm. The ettringite morphology appeared unaltered when observed after 6 hours of hydration. Therefore, the LSs was found not to change the morphology of ettringite in the systems analysed in this PhD thesis.
The large amount of ettringite formed provided additional surface area, which increased the LSs consumption for monolayer surface adsorption. This was found to be the main mechanism of LSs consumption for CX cement both for IA and for DA. Monolayer surface adsorption was also found to be the main mechanism of LSs adsorption for ANL cement for DA, while other mechanisms, still to be determined, appeared to play a role for ANL cement for IA. For both cements, calcium complexation, multilayer adsorption and intercalation in AFm were considered unlikely.
The large amount of ettringite formed appeared to decrease the workability of cement paste, leading to early stiffening and, in some cases, to rapid set. The workability of cement paste with LSs also seemed directly correlated to the degree of LSs coverage of the available surface for adsorption. A sudden drop in yield stress and viscosity was measured for the cement pastes that reached an adsorption plateau (DA). Samples which did not reach surface saturation (IA) showed a more gradual increase in workability, requiring higher LSs dosages when compared to those needed for DA. However, for DA, both cement pastes were found to be very sensitive to variations in LSs dosage: even a small increase from the optimal LSs dosage could lead to sudden slump loss.
As to the impact of LSs on setting time, the setting retardation was found to be directly correlated to the amount of free LSs in the pore solution. The DA of LSs was found to lead to higher setting retardation, because of the lower LSs consumption by the cement paste compared to when the LSs was added with IA. This led to a higher amount of free LSs available to retard C3S hydration. In the samples where the highest amount of ettringite was formed, the increased LSs adsorption caused by the additional surface area reduced the amount of free LSs in the pores solution. This was reflected in lower setting retardation, which was measured with isothermal calorimetry. In addition, increasing LSs dosages led to larger retardation of the silicate peak compared to the aluminate one, causing the two peaks to merge. This can potentially lead to poisoning of C3S hydration and severe delay of setting, causing incompatibility between plasticizer and cement.
In conclusion, the use of the LSs studied in this PhD thesis in combination with cement characterized by high C3A content and fineness appears critical, as possibly leading to incompatibility issues such as higher LSs dosage needed to reach a given workability, severe setting retardation, rapid set, and sudden slump loss. Therefore, before using LSs in the concrete practice, special attention should be paid to the combination between the LSs and the cement chosen
Crosslinking UV-curable polymers with organic dyes for highly stable, multifunctional, light-harvesting luminescent solar concentrators
No full textA multifunctional luminescent system characterized by outstanding durability is presented in this work as polymeric matrix for luminescent solar concentrators (LSCs). Such coating was fabricated by embedding a modified perylene-based organic dye in a fluorinated matrix consisting in a blend of photo-curable fluorinated polymers. The coating can easily crosslink when exposed to UV-light. The presence of lateral double bonds in the organic dye molecule enables its co-crosslinking with the acrylate fluorinated matrix. Multifunctionality is granted to the coating by remarkably high water contact angle values, slightly exceeding 120°, which impart easy cleaning properties to the LSC device. Accelerated weathering tests (800 h) showed the outstanding stability of LSCs prepared using the fluorinated matrix co-crosslinked with the modified perylene presented here. These devices retained their initial optical efficiency during the intense weathering test. On the contrary, devices fabricated with the same fluorinated polymers, but incorporating a similar dye with the same chemical structure except for the lateral double bonds enabling co-crosslinking with the polymeric matrix, exhibited a 10% efficiency loss over the testing time. The increased stability can be explained by taking into account the effect of the linkage between the organic dye and the host matrix. The fast and easy preparation process presented in this work represents a scalable approach to remarkably stable and truly multifunctional LSCs
Development of the hub port of Colombo, Sri Lanka
No full textThe Port of Colombo, Sri Lanka, is an important hub port in the Indian Ocean. A hub port is a port with mainly transhipment (and in this case container) throughput, which means that most of the cargo is not for the country itself, but for countries in the region. The yearly container throughput at the Port of Colombo reached its full capacity of 1.7 million TEU per year in 1997. Increasing waiting times for ships calling at the port are a result of this. Because of the costs of a waiting ship, shipping lines will choose other ports in the region such as Singapore, Salalah (Oman) or Dubai (United Arab Emirates) for their ships to go to. The aim of this study is to develop a plan for a New Container Terminal, which will give the Port of Colombo enough container throughput capacity for the next 25 years: till the year 2025.Hydraulic EngineeringCivil Engineering and Geoscience
Dissomphalus miriamae Colombo & Azevedo, sp. nov.
No full textDissomphalus miriamae Colombo & Azevedo, sp. nov. (Figs 12, 150, 151) Description. Male. Head and mesosoma black; metasoma dark castaneous or black. Mandible with two apical teeth; clypeus broadly projected forward, median tooth weakly rounded; frons weakly coriaceous and punctate. Mesosoma. Weakly coriaceous. T2 without tergal process. Posterior hypopygeal margin concave. Genitalia: paramere small in dorsal view, apex rounded, arched, smaller than basiparamere; cuspis wide; digitus wide; aedeagal ventral ramus smaller than dorsal body, apex ill defined, laminar, narrow; aedeagal dorsal body with one pair of apical lobes, inner pair with apex rounded in dorsal view, inner pair weakly serrate; basal process ill defined; apodeme extending beyond genital ring. Female unknown. Remarks. This species is allocated in amplus species-group by having the tergal process absent. This species not is similar other of species-group. This species is mainly different because has the aedeagal dorsal body with one pair of apical lobes and inner pair weakly serrate. Material examined. Types: Holotype Ƌ, BRAZIL, E[spírito] S[anto]: Santa Teresa, Est [ação] Biol [ógica] de Santa Lúcia, 28.III.2001, varredura, Azevedo & Kawada col. (UFES). Paratypes: 2Ƌ, Santa Teresa, Est [ação] Biol [ógica] de Santa Lúcia, 31.V.2001, 2♂, 27.IX.2001, varredura, Azevedo & Kawada col. (UFES); 1♂, Santa Maria de Jetibá, Fazenda Paulo Seick, 20º02’S 40º42’W, 29.XI–06.XII.2002, armadilha Malaise, Tavares & Azevedo e eq[uipe] col. (UFES); 1♂, Vitória, P [ar]q[ue] Est [adual] Fonte Grande, 30.VI.2001, varredura, Azevedo & Kawada col. (UFES). Etymology. The epithet miriamae is in allusion to the mother’s second author name Miriam. Distribution. Brazil (Espírito Santo).Published as part of Colombo, Wesley D. & Azevedo, Celso O., 2016, Review of Dissomphalus Ashmead, 1893 (Hymenoptera, Bethylidae) from Espíri- to Santo, Brazil, with description of twenty-one new species, pp. 1-84 in Zootaxa 4143 (1) on pages 41-42, DOI: 10.11646/zootaxa.4143.1.1, http://zenodo.org/record/26075
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