117,543 research outputs found
Ruolo dello scambiatore sodio-calcio 1 nell'ipertrofia cardiaca indotta da batteri
No full textL ipertrofia cardiaca (CH) in condizioni patologiche e un processo mal adattativo in risposta ad un
aumentato stress biomeccanico e accompagna varie forme di malattie cardiache. I meccanismi alla
base di questo processo patologico (argomento di studio di numerose ricerche) coinvolgono spesso
perturbazioni funzionali nell omeostasi del [Ca2+]i. Uno dei principali regolatori del [Ca2+]i nel
cuore e il trasportatore sodio/calcio 1 (NCX1). Le infezioni batteriche possono causare CH,
alterando direttamente o indirettamente l omeostasi del [Ca2+]i. In questo studio abbiamo
investigato l ipotesi che NCX1 sia determinante per l induzione e progressione dei danni cardiaci
da infezioni batteriche. Risultati ottenuti nel nostro laboratorio hanno dimostrato che l LPS, la
principale tossina dei Gram-negativi, induce CH che e contrastata da ciclosporina nei modelli dei
cuori perfusi ex vivo, in cardiomiociti primari e in linee cellulari cardiache. In tutti i sistemi
analizzati, abbiamo trovato alterazioni significative a carico di NCX1 dopo esposizione a 1 g/ml
LPS per 3 e 24 h. In particolare, l LPS aumenta l espressione di NCX1 (mRNA e proteina) senza
alterarne la distribuzione cellurare. L aumento della proteina NCX1 e stato osservato anche in
miociti in cui l espressione dello scambiatore non era regolata dall attivita del promotore
endogeno. In aggiunta, cellule esprimenti NCX1 hanno sviluppato difetti nel controllo del calcio
intracellulare dopo esposizione a LPS, dato che l ingresso di calcio nella cellula via il reverse
mode di NCX1 era significativamente elevato nelle cellule stressate. Abbiamo trovato anche che
NCX1 e critico per la risposta ipertrofica da LPS, la quale era completamente bloccata
dall inibitore specifico di NCX1 SN6. Infine, in miociti privi di NCX1 la risposta ipertrofica
all LPS era significativamente attenuata. Questi dati suggeriscono che NCX1 sia un nuovo
bersaglio farmacologico da considerare per la prevenzione del danno cardiaco da batteri
Perovskite Single‐Crystal Solar Cells: Advances and Challenges
No full textDe Marco L, Nasti G, Abate A, Rizzo A. Perovskite Single‐Crystal Solar Cells: Advances and Challenges. Solar RRL. 2022;6(7): 2101085
Analysis and Verification of Robustness Properties in Becker-Döring Model
No full textMany biochemical processes in living cells involve clusters of particles. Such processes include protein aggregation and the development of intracellular concentration gradients. To study these mechanisms, we can apply coagulation-fragmentation models describing populations of interacting components. In this context, the Becker-Döring equations - theorized in 1935 - provide the simplest kinetic model to describe condensations phenomena. Experimental works on this model reveal that it exhibits robustness, defined as the system’s capability to preserve its features despite noise and fluctuations. Here, we verify the robustness of the BD model, applying our notions of initial concentration robustness (α -robustness and β -robustness), which are related to the influence of the perturbation of the initial concentration of one species (i.e., the input) on the concentration of another species (i.e., the output) at the steady state. Then, we conclude that a new definition of robustness, namely the asymptotic robustness, is necessary to describe more accurately the model’s behavior
Formal characterization and efficient verification of a biological robustness property
No full textRobustness is an observable property for which a chemical reaction network (CRN) can maintain its functionalities despite the influence of different perturbations. In general, to verify whether a network is robust, it is necessary to consider all the possible parameter configurations. This is a process that can entail a massive computational effort. In the work of Rizk et al., the authors propose a definition of robustness in linear temporal logic (LTL) through which, on the basis of multiple numerical timed traces obtained by considering different parameter configurations, they verify the robustness of a reaction network. In this paper, we focus on a notion of initial concentration robustness (alpha -robustness), that is related to the influence of the perturbation of the initial concentration of one species (i.e., the input) on the concentration of another species (i.e., the output) at the steady state. We characterize this notion of robustness in the framework proposed by Rizk et al., and we show that, for monotonic reaction networks, this allows us to drastically reduce the number of traces necessary to verify robustness of the CRN
New Opportunities in the Supercritical CO2 Extraction of Polyphenols from Agri-Food Residues
No full textThe potential of agri-food residues as sources of functional ingredients and their recovery has been markedly intensified in the last years as a strategy to valorize and exploit their byproducts in the biomedical or cosmeceutical fields. The extraction of bioactive material from the original matrices has always been one of the critical points to effectively develop on industrial scale the study of agri-food residues and to make the process environmentally and economically sustainable. Common extraction methods, like Soxhlet or maceration, are the most used for the majority of the organic natural compounds, from apolar to polar, from fats to saponins and polyphenols, although the massive use of organic solvents can in some cases prevent the eco-sustainability of the overall process. In fact, the industrial approach is often to use water as an extraction solvent, but this also represents a problem in terms of environmental sustainability, as water is a precious good.
Supercritical fluid extraction (SFE) with carbon dioxide has recently become an interesting green technique to extract compounds soluble in CO2, thus perfectly applicable to lipophilic compounds like fats [1].
The peculiarity properties of SFE ensure safe and not expensive extractions with low environmental impact [2].
Moreover, CO2 is easily removed from the solid at ambient conditions and/or, on industrial scale, can be recovered through specific apparatus for its freshly reuse. A further advantage is the limited use of organic solvent for extraction of more polar species (i.e. phenolic acids, anthocyanins, flavonoids, etc [3,4]) employing in most case ethanol as co-solvent, which is well tolerated by various industrial sectors. Additionally, the relatively low critical temperature of CO2 allows the extraction of thermolabile substances avoiding their degradation. In spite of these advantages, very few applications to extract polar compounds have so far been reported.
Our ongoing projects focus on the valorization of wastes from different natural solid matrices with a special emphasis on polyphenols. Several secondary metabolites of plants and animals display a polyphenolic structure.
These molecules are generally involved in defense against ultraviolet radiation or aggression by pathogens. The reason for the widespread interest in polyphenols is the recognition of their antioxidant properties, their great abundance in our diet, and their alleged role in the prevention of various diseases associated with oxidative stress [5].
Here we report the application of supercritical fluid extractions using carbon dioxide added with an organic modifier (ethanol or methanol) from different agri-food wastes. The experimentation successfully resulted in the extraction of polyhydroxylated naphtoquinones from sea urchins wastes, ellagic acid from pomegranate fermentation [6] and chlorogenic acids from byproducts of coffee roasting.
The effects of the main operating conditions of extraction, namely, temperature, pressure and modifier percentage, on the extraction yield and the corresponding analytical profile were assessed.
The results show a substantial advantage with respect to a Soxhlet extraction in terms of easy recovery, selectivity, compounds stability, time, and an overall total energy saving
Supercritical CO2 extraction of polyphenols from agri-food residues
No full textIntroduction Environmental concerns arising from the use of organic solvents in extraction procedures might be overcome by an innovative technology: supercritical CO2 (scCO2). It enables the extraction of compounds soluble in scCO2, perfectly applicable to lipophilic molecules (1). The addition of a co-solvent is able to modify the polarity of the fluid allowing the extraction of more polar molecules (2). Despite these advantages, very few applications to extract polar compounds have so far been reported. Material & Methods Sea urchin wastes, pomegranate fermentation byproducts and residues of coffee roasting were loaded in the extraction vessel. scCO2 extractions were performed in the presence of co-solvents (ethanol, methanol, ethylacetate) at different T and p. Results Changes in the operative conditions led to selective extraction of classes of compounds. The procedure was assessed to yield polyhydroxylatednaphtoquinones from sea urchins’ wastes, ellagic acid from pomegranate fermentation wastes (3) and chlorogenic acids from byproducts of coffee-roasting. Conclusions Effects of main operating conditions (temperature: 35-55°C, pressure: 300-400 bar and co-solvent: 5- 20%) have been assessed. The addition of a co-solvent was necessary to enable polyphenols extraction. Yields were lower compared to conventional extractions, however scCO2 provided high-purity extracts, as demonstrated by the enhanced antioxidant activity
Valorization of agro-industrial fermentation residues: biotransformation of ginger active molecules
No full textThe ginger rhizome is a primary ingredient of oriental food, beverage, and herbal medicine catching on Western Countries meals. In 2016 the food sector processed 3.3 million tonnes of ginger generating a pulp waste that was mostly destined to agricultural field, biorefinery, papermaking etc.1 The ginger pulp waste still contains an oleoresin rich in gingerol-like compounds, such as gingerols and shogaols, bioactive components with recognized anti-inflammatory and anticancer properties.2,3
As an alternative valorisation strategy, the recovery of the main ginger waste components and their biotransformation to generate a small library of optically enriched derivatives was herein investigated. The oleoresin was first extracted from a fermented ginger biomass originating from a local farm. The conventional extraction confirmed the presence of still 30% gingerol-like compounds with unaltered chemical profile as characterized and quantified by UPLC-TUV and GC-MS. Then the enantioselective reduction of prochiral carbonyl moiety of pure isolated 6-gingerol (1), 8-gingerol (2), 6-shogaol (3), 8-shogaol (4), 6-paradol (5), 8-paradol (6) and zingerone (7) by different alcohol dehydrogenases (ADHs)4 was investigated. From our preliminary results, no ketone reduction was observed for 3 and 4. As far as the other substrates concern, only the ADH from Micrococcus luteus and engineered ADHs from Evoxx led to chiral alcohols in low yield, but with good diastereo- and enantiomeric excess (d.e and e.e) (Figure 1)
Silverskin: from waste to a renewable source of bioactive compounds
No full textSilverskin is the thin layer covering the coffee beans. During the roasting coffee process, it is removed becoming a by-product. The large production (150.000 t/year on global scale, of which 7.500 t/years in Italy) of this waste calls for its re-functionalization in order to reduce the impact of industrial by-products in the environment. Currently the only use of coffee silverskin (CS) is as renewable energy source or as fertilizer (1,2), no other utilization has been developed for CS so far. Despite this, the chemical composition of CS indicates the presence of interesting bioactive molecules (i.e. lipids, chlorogenics acids, caffeine) that confer to this by-product antioxidant and prebiotic properties. (3)This evidence suggests its re-use as well in other industrial fields such as nutraceutical, cosmetic and pharmaceutical as aimed by CirCO project. In this hypothesis of revalorization, it cannot be excluded the potential use of CS lipid matter in cosmetic formulations or as additive for the technology of paper processing (4). For the isolation of CS oil, supercritical CO2 was selected as more sustainable separation technique, alternative to classical solvent extraction processes.(5) We observed that an appropriate modulation of process parameters (T, P) influence the oil rate and the chemical composition opening the way for targeted extraction. In details the application of mild conditions (35°C, 100/200psi) led to majority extraction of palmitic (C16:0) and linoleic (C18:2) acids with an overall yield of 1.9% (goil/100gCS). The increase of pressure (100 bar300 bar) and temperature (35°C60°C) promoted the extraction of arachidic acid (C20:0), behenic acid (C22:0) and lignoceric acid (C24:0) with a calculated oil yield of 3.3% (goil/100gCS). The best identified conditions were employed for the industrial scale-up giving results comparable to laboratory scale. For a possible commercial process application, it is essential to test the applicability of appropriate models for SFE of lipids from oil-containing substrates.(5) For this purpose a mathematical model is constructed based on the experimental data collected, employed apparatus and chemical-physical characteristic of biomass in tightly collaboration with prof. Manenti at Politecnico of Milan
Strategie cognitivo-affettive e rischio di infezione da H.I.V.: uno studio sull’efficacia di due differenti metodologie di prevenzione primaria
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