Physical properties of coffee related to the roasting process

Roasting is one of the most important processes regarding the final quality and physical properties of coffee. This work was done with the aim of analyzing the change in the physical properties of coffee during the roasting process. More specifically, the variations of the orthogonal axes, the circularity, the sphericity, the mass loss and the surface and volumetric expansions of the coffee beans subjected to the roasting process were analyzed. The Arabica coffee variety was classified in shape and size using a sieve. The samples were then stored in polyethylene bags in refrigeration chambers at 18 °C to maintain the initial characteristics before roasting. After that, roasting was carried out at the temperatures of either 220, 240, 260, 280 or 300 °C over a period of 600 seconds. Specifically, the rotary cylinder direct gas firing roaster, used at 45 rpm, was held for 10 min at one of the respective roasting temperatures (220, 240, 260, 280, 300 ºC) in each case. The air temperature was measured by a type k thermocouple positioned inside the cylinder and controlled manually with a gas step valve. Five air temperatures were set inside the cylinder. The surface temperature was measured by an infrared thermometer (Testo 830-T1). The experiment was performed with 3 repetitions for each temperature and each sample. Every 20 seconds, 10 grams of coffee beans were taken from the roaster and measurements were taken using a caliper rule, in order to obtain the dimensions of the beans. In general, the physical parameters analyzed were evidently affected by temperature, the impact being more significant at higher ones. Graphically, the differences in terms of distance between the thermal curves are shown on average starting from 400 seconds, to then stabilize at the end of the process. In general, the parameters of sphericity, circularity, mass loss, surface expansion and volumetric expansion show linear increases over time.A torrefação é um dos processos mais importantes em relação à qualidade final e às propriedades físicas do café. Este trabalho foi realizado com o objetivo de analisar as alterações nas propriedades físicas do café durante o processo de torrefação. Mais especificamente, foram analisadas as variações dos eixos ortogonais, a circularidade, a esfericidade, a perda de massa e as expansões superficial e volumétrica dos grãos de café submetidos ao processo de torrefação. A variedade de café arábica foi classificada em forma e tamanho usando uma peneira. As amostras foram então armazenadas em sacos de polietileno em câmaras de refrigeração a 18 ° C para manter as características iniciais antes da torrefação. Depois disso, a torrefação foi realizada nas temperaturas de 220, 240, 260, 280 ou 300 ° C durante um período de 600 segundos. Especificamente, a torrefadora a gás de cilindro direto, usada a 45 rpm, foi mantida por 10 minutos em uma das respectivas temperaturas de torrefação (220, 240, 260, 280, 300 ºC) em cada caso. A temperatura do ar foi medida por um termopar tipo k posicionado dentro do cilindro e controlado manualmente com uma válvula de passagem de gás. Cinco temperaturas do ar foram definidas dentro do cilindro. A temperatura da superfície foi medida por um termômetro infravermelho (Testo 830-T1). O experimento foi realizado em 3 repetições para cada temperatura e cada amostra. A cada 20 segundos, 10 gramas de café em grão foram retirados da torrefadora e as medições foram realizadas usando uma régua de pinça, a fim de obter as dimensões dos grãos. Em geral, os parâmetros físicos analisados foram evidentemente afetados pela temperatura, sendo o impacto mais significativo nos mais altos. Graficamente, as diferenças em termos de distância entre as curvas térmicas são mostradas em média a partir de 400 segundos, para estabilizar no final do processo. Em geral, os parâmetros de esfericidade, circularidade, perda de massa, expansão superficial e expansão volumétrica mostram aumentos lineares ao longo do tempo

Guarigione transmurale in pazienti affetti da malattia di Crohn in terapia di mantenimento con farmaci anti-TNF alfa

La malattia di Crohn è una malattia infiammatoria cronica intestinale, che può colpire qualsiasi tratto del canale alimentare, ha un decorso cronico-recidivante, e tipicamente coinvolge tutti gli strati della parete intestinale. Gli obiettivi della terapia medica nella malattia di Crohn sono la remissione clinica libera da steroidi e la guarigione mucosale. In questo studio si è considerato un endpoint terapeutico ad oggi mai valutato, la guarigione transmurale, intesa come la normalizzazione dell’ispessimento infiammatorio della parete intestinale nei tratti coinvolti dalla malattia, in pazienti trattati con farmaci anti-TNF α, usando due metodiche di imaging: l’ecografia intestinale e l’entero-RM

Design and development of new nanosystem based on self-assembly peptides for nanomedicine applications

Peptide-based materials (PBMs) generate by the aggregation of amphiphilic monomers represent a rapidly growing tool within materials science. They have been considered for several applications in different fields from electronic to nanomedicine. According to an appropriate design, amphiphilic peptides can spontaneously assemble in well-structured supramolecular materials as result of an intricate network of inter- and/or intra-molecular interactions between hydrophobic and hydrophilic portions. The interaction manner can strongly influence both morphology and properties of the final supramolecular materials. Aromaticity is the terms used to describe the particular molecular stability associated to a cyclic shaped and planar chemical entity with a ring of resonance bonds. The peculiar electronic structure of aromatics molecules arouses their interesting physicochemical properties. All the classes of intermolecular forces known as the aromatic interaction give raise from it. The knowledge and the study of aromatic interaction contaminated peptide based material field too. To this day, using self-assembly as instrument of bottom-up nano-plenning, it is a clear evidence that aromatic peptide sequences, containing phenylalanine (Phe), tyrosine (Tyr) or tryptophan (Trp), can be opportunely modulated to the aim of generate the required supramolecular architecture. The forefather of this new class of peptide monomers is the well-known diphenylalanine (FF) homopeptide. Through a combination of π-π staking and hydrogen-bonding, different method of preparation, specific pH values or solvent, FF is able to self-organize in different kinds of nano- and macro- morphologies (hollow nanotubes, fibers, vesicles, metastable hydrogels or organogels). By this evidence, many structural analogues of diphenylalanine were studied and peptide nanostructures containing the FF motif or more extended aromatic sequences have been investigated for their mechanical, electrochemical and optical properties, and more recently for some nanomedicine applications. Nevertheless, the majority of studies reported in literature are principally focused on clarifying the physicochemical aspects responsible for array stability in FF based nanostructures, whereas only few studies have been devoted in the investigation of FF aggregates for biomedical applications. This essentially because of the intrinsic low water solubility of these peptide sequences. According to these considerations, during the three years of the PhD project, novel poly-phenylalanine self-assembling conjugates were carefully designed, synthetized and fully characterized. The final peptide materials were evaluated for potential applications in bio-imaging field (with particular bearing to Magnetic Resonance Imaging and fluorescence imaging). It was also appreciate as the chemical modification of the aromatic framework with chelating agents, gadolinium (Gd) complexes, and polyethylene glycol (PEG) fragments with different length can affect the structural organization and the supramolecular behavior of the nanomaterial. The result produced on the hierarchical organization by the chemical replacement of the Phe with others aromatic amino acids (such as tryptophan, tyrosine and 2-naphthylalanine) was also investigated. The entirety of collected data during this PhD project permits to highlight the possible relationship existing between the chemical structure of the proposed building blocks, the final supramolecular nanostructure, and their functional features. In order to simplify the comprehension and the discussion of the results (Chapter III), they will be argued in three separate sections: • Section I: PBMs as supramolecular contrast agents for MRI. • Section II: PBMs as photoluminescent supramolecular probes. • Section III: PBMs obtained by punctual chemical modifications of homophenylalanine sequences. In Section I, an innovative class of supramolecular CAs for MRI, based on peptide self-assembly monomers, is described and analyzed. Different design strategies were applied to obtain and improve the aggregation phenomenon. The structural and relaxometric properties of each self-assembling system are discussed and mutually compared. The improved values of relaxivity and the exanimated capability to encapsulate the doxorubicin anticancer drug suggest a potential use of the proposed nanostructures as new theranostic platform. Photoluminescent (PL) phenomena in peptide-based materials are the subject of Section II. A class of novel PEGylated homo-phenylalanine was synthetized and, due to the high content of β-sheet, the final self-assembled systems show blue PL emission. A red-shift of the fluorescence was actualized by FRET phenomena between the nanostructure and a internalized NBD dye. Committing to the hydrogen bonding hypothesis, a relationship between observed PL and the number of interaction sites in nanostructures was developed. In Section III the effect of a punctual chemical modification on peptide primary sequence will be elucidated. Hetero- and homo-sequences were derived simply by the replacement of Phe residues with tyrosine and tryptophan ones. Characteristic gelification behavior was found for peptides containing Tyr. WAXS/SAXS studies and molecular dynamic simulations supported the structural analysis of the new peptide-based materials. The experimental protocols are totally collected in the dedicated Experimental section. The full characterization of synthetized peptides, conjugates and derivatives is reported in Appendix I, meanwhile additional information, Tables and Figures are gather together in Appendix II

Fmoc-Diphenylalanine Hydrogels: Optimization of Preparation Methods and Structural Insights

Hydrogels (HGs) are tri-dimensional materials with a non-Newtonian flow behaviour formed by networks able to encapsulate high amounts of water or other biological fluids. They can be prepared using both synthetic or natural polymers and their mechanical and functional properties may change according to the preparation method, the solvent, the pH, and to others experimental parameters. Recently, many short and ultra-short peptides have been investigated as building blocks for the formulation of biocompatible hydrogels suitable for different biomedical applications. Due to its simplicity and capability to gel in physiological conditions, Fmoc-FF dipeptide is one of the most studied peptide hydrogelators. Although its identification dates to 15 ago, its behaviour is currently studied because of the observation that the final material obtained is deeply dependent on the preparation method. To collect information about their formulation, here are reported some different strategies adopted until now for the Fmoc-FF HG preparation, noting the changes in the structural arrangement and behaviour in terms of stiffness, matrix porosity, and stability induced by the different formulation strategy on the final materia

Shallow to intermediate resistivity features of the Colfiorito Fault System inferred by DC and MT survey

Over the last decade electromagnetic (EM) measurements have provided new constraints on the upper-crustal structure of the major fault zones in the world, both when they act as conduit and as a barrier, due to strong sensitivity of resistivity to fluids circulation and mineralization. On the track of a high impact magnetotelluric (MT) study performed across the San Andreas Fault, high resolution EM data were collected in the Colfiorito epicentral area along profiles crossing some main fault lineaments. Being the study focussed both on shallow that on intermediate resistivity distribution in the brittle upper-crust, a MT profile was integrated by several electrical resistivity tomographies (ERT). The latter were successful in locating faults even where the structures are buried by a wide covering of Quaternary deposits and in the recognition of different electrical signatures of the faults. MT resistivity model crossing Mt. Prefoglio normal fault clearly imaged the typical thrust structures of the area and a high conductive zone spatially related to the fault. Seismicity seems to be located outside such conductive area, whose behaviour suggests a fluidised and altered zone incapable of supporting significant stress internally

Forward precision medicine: Micelles for active targeting driven by peptides

Precision medicine is based on innovative administration methods of active principles. Drug delivery on tissue of interest allows improving the therapeutic index and reducing the side effects. Active targeting by means of drug-encapsulated micelles decorated with targeting bioactive moieties represents a new frontier. Between the bioactive moieties, peptides, for their versatility, easy synthesis and immunogenicity, can be selected to direct a drug toward a considerable number of molecular targets overexpressed on both cancer vasculature and cancer cells. Moreover, short peptide sequences can facilitate cellular intake. This review focuses on micelles achieved by self-assembling or mixing peptide-grafted surfactants or peptide-decorated amphiphilic copolymers. Nanovectors loaded with hydrophobic or hydrophilic cytotoxic drugs or with gene silence sequences and externally functionalized with natural or synthetic peptides are described based on their formulation and in vitro and in vivo behaviors

Monster parastomal pyoderma gangrenosum effectively treted by topical tacrolimus.

Terapia del pyoderma gangrenoso parastomale refrattario in malattia di Crohn. Il trattamento si è basato sull'applicazione topica di tacrolimus pomata. Dopo la suddetta terapia si è osservata la guarigione delle lesioni cutanee

When Standard Is Not Enough: a Conceptualization of AI Systems’ Customization and its Antecedents

The centrality of information systems (IS) customization to match companies’ needs with software systems available in the market has been researched extensively. The distinctive characteristics of Artificial Intelligence (AI) systems compared to other types of IS suggest that customization needs a new conceptualization in this context. We draw on evidence from expert interviews to conceptualize customization of AI systems as composed of four layers: data, models, algorithms, infrastructures. We identify a continuum of levels of customization, from no to complete customization. Since companies customize AI systems in response to business needs, we develop a theoretical model with six antecedents of AI systems’ customization choices. In so doing, we contribute to both AI management research, by introducing the IS customization perspective in the field, and IS customization literature, by introducing AI systems as a novel class of systems and enlarging the understanding of customization for a specific class of software systems

Peptide-Based Soft Hydrogels Modified with Gadolinium Complexes as MRI Contrast Agents

Poly-aromatic peptide sequences are able to self-assemble into a variety of supramolecular aggregates such as fibers, hydrogels, and tree-like multi-branched nanostructures. Due to their biocompatible nature, these peptide nanostructures have been proposed for several applications in biology and nanomedicine (tissue engineering, drug delivery, bioimaging, and fabrication of biosensors). Here we report the synthesis, the structural characterization and the relaxometric behavior of two novel supramolecular diagnostic agents for magnetic resonance imaging (MRI) technique. These diagnostic agents are obtained for self-assembly of DTPA(Gd)-PEG8-(FY)3 or DOTA(Gd)-PEG8-(FY)3 peptide conjugates, in which the Gd-complexes are linked at the Nterminus of the PEG8-(FY)3 polymer peptide. This latter was previously found able to form selfsupporting and stable soft hydrogels at a concentration of 1.0% wt. Analogously, also DTPA(Gd)PEG8-(FY)3 and DOTA(Gd)-PEG8-(FY)3 exhibit the trend to gelificate at the same range of concentration. Moreover, the structural characterization points out that peptide (FY)3 moiety keeps its capability to arrange into β-sheet structures with an antiparallel orientation of the β-strands. The high relaxivity value of these nanostructures (~12 mM−1·s−1 at 20 MHz) and the very low in vitro cytotoxicity suggest their potential application as supramolecular diagnostic agents for MRI

Peptide-based hydrogels and nanogels for delivery of doxorubicin

Introduction: The clinical use of the antitumoral drug doxorubicin (Dox) is reduced by its dose-limiting toxicity, related to cardiotoxic side effects and myelosuppression. In order to overcome these drawbacks, here we describe the synthesis, the structural characterization and the in vitro cytotoxicity assays of hydrogels (HGs) and nanogels (NGs) based on short peptide sequences loaded with Dox or with its liposomal formulation, Doxil. Methods: Fmoc-FF alone or in combination with (FY)3 or PEG8-(FY)3 peptides, at two different ratios (1/1 and 2/1 v/v), were used for HGs and NGs formulations. HGs were prepared according to the “solvent-switch” method, whereas NGs were obtained through HG submicroni-tion by the top-down methodology in presence of TWEEN®60 and SPAN®60 as stabilizing agents. HGs gelation kinetics were assessed by Circular Dichroism (CD). Stability and size of NGs were studied using Dynamic Light Scattering (DLS) measurements. Cell viability of empty and filled Dox HGs and NGs was evaluated on MDA-MB-231 breast cancer cells. Moreover, cell internalization of the drug was evaluated using immunofluorescence assays. Results: Dox filled hydrogels exhibit a high drug loading content (DLC=0.440), without syneresis after 10 days. Gelation kinetics (20–40 min) and the drug release (16–28%) over time of HGs were found dependent on relative peptide composition. Dox filled NGs exhibit a DLC of 0.137 and a low drug release (20–40%) after 72 h. Empty HGs and NGs show a high cell viability (>95%), whereas Dox loaded ones significantly reduce cell viability after 24 h (49–57%) and 72 h (7–25%) of incubation, respectively. Immunofluorescence assays evidenced a different cell localization for Dox delivered through HGs and NGs with respect to the free drug. Discussion: A modulation of the Dox release can be obtained by changing the ratios of the peptide components. The different cellular localization of the drug loaded into HGs and NGs suggests an alternative internalization mechanism. The high DLC, the low drug release and preliminary in vitro results suggest a potential employment of peptide-based HGs and NGs as drug delivery tools