777 research outputs found
MABS validation through repeated execution and data mining analysis
No full textAgent Based Modelling is the most interesting and advanced approach for simulating a complex system: in a social context, the single parts and the whole are often very hard to describe in detail. Besides, there are agent based formalisms which allow to study the emergency of social behaviour with the creation and study of models, known as artificial societies. Thanks to the ever increasing computational power, it's been possible to use such models to create software, based on intelligent agents, which aggregate behaviour is complex and difficult to predict, and can be used in open and distributed systems. Data mining is born in the last decades in order to help users in finding useful knowledge from the otherwise overwhelming amount of data available nowadays from the web and the data collected every day by companies. Data Mining techniques can therefore be the keystone to reveal non-trivial knowledge expressed by the initial assumption used to build the micro-level of the model and the structure of the society of agents that emerged from the simulation
Application of structure-based thermodynamic calculations to the rationalization of the enantioselectivity of subtilisin in organic solvents
No full textThe effect of organic solvents on the selectivity of lyophilized or CLEC
(cross-linked enzyme crystals)-subtilisin in the resolution of
sec-phenethyl alcohol and trans-sobrerol was studied. A theoretical
model, that tries to predict solvent effects on enantioselectivity only
as a function of the activity coefficients of the desolvated part of the
substrate in the relevant transition state of the reaction (Ke, T.;
Wescott, C. R.; Klibanov, A. M. J. Am. Chem. Sec., 1996, 118, 3366) was
examined and shown to agree poorly with the experimental data. The
tetrahedral intermediate was studied with MonteCarlo molecular
mechanics, and the activity coefficients were calculated with UNIFAC.
(C) 1998 Elsevier Science Ltd. All rights reserved
Enantioselective aldol reaction catalised by polyleucines as synthetic enzymes
No full textPolyleucines of various lengths act as enantioselective catalysts in the aldol condensation between cyclohexanone and a series of aromatic aldehydes, a reaction which may be of prebiotic significance. (c) 2007 Elsevier Ltd. All rights reserved
Identifying Antimicrobial Agents from Chlorella sorokiniana: A Biotechnological Approach Utilizing Eco-Friendly Extraction and Characterization Methods
No full textNatural compounds are increasingly favored over synthetic ones for their lower environmental impact. However, extraction and characterization processes typically rely on harsh conditions and conventional solvents, which are unsustainable and cause pollution. This study aimed to develop an eco-friendly extraction method to isolate and evaluate the antimicrobial properties of bioactive compounds from Chlorella sorokiniana. Using dimethyl carbonate (DMC), methoxycyclopentane (CPME), and butan-2-one (MEK) as green solvents alongside chloroform as a non-green reference solvent, on both untreated and sodium hydroxide pre-treated microalgae biomass, extract yields of up to 182 ± 27 mg/g DW were obtained using MEK. Extracts from untreated microalgae biomass exhibited lower MIC values compared to those obtained with the same solvent from pre-treated biomass, when tested as antimicrobial agents against Escherichia coli, Bacillus megaterium, and Bacillus subtilis. The lowest MIC value (4.89 ± 0.05 μg/mL) was observed against E. coli using the extract from the untreated microalgae biomass with CPME, which was comparable to the vancomycin control (1.55 ± 0.03 μg/mL). Principal component analysis highlighted correlations between GC-MS-identified compounds and antimicrobial activity. ANOVA and post hoc tests (p < 0.05) confirmed solvent choice, and pre-treatment influenced yield and bioactivity. The results underscore green solvents as sustainable alternatives for extracting bioactive compounds from autotrophic microalgae
Engineering dielectric materials for high-performance organic light emitting transistors (Olets)
No full textFunding Information: The Author thanks the support from Academy of Finland Flagship Program (Grant No.: 320167, PREIN). Author thanks Gianluca Generali and many colleagues in ETC srl and CNR-ISMN (Italy) for valuable discussions on organic light emitting transistors during the years. Funding Information: Acknowledgments: The Author thanks the support from Academy of Finland Flagship Program (Grant No.: 320167, PREIN). Author thanks Gianluca Generali and many colleagues in ETC srl and CNR-ISMN (Italy) for valuable discussions on organic light emitting transistors during the years. Publisher Copyright: © 2021 by the author. Licensee MDPI, Basel, Switzerland.Organic light emitting transistors (OLETs) represent a relatively new technology platform in the field of optoelectronics. An OLET is a device with a two-fold functionality since it behaves as a thin-film transistor and at the same time can generate light under appropriate bias conditions. This Review focuses mainly on one of the building blocks of such device, namely the gate dielectrics, and how it is possible to engineer it to improve device properties and performances. While many findings on gate dielectrics can be easily applied to organic light emitting transistors, we here concentrate on how this layer can be exploited and engineered as an active tool for light manipulation in this novel class of optoelectronic devices.Peer reviewe
First Maltese record of Stephanopachys quadricollis (Marseul, 1879) (Coleoptera, Bostrichidae)
No full textThree specimens of Stephanopachys quadricollis (Marseul, 1878) were recently found in Malta in UV light
traps and represent the first record of this species for this country. Although S. quadricollis is native to
the Mediterranean basin, it is not yet clear if these Maltese records are due to a natural population or to
an interception. Distributional, nomenclatural and biological data on this species are summarized, and a
new synonymy is established: Stephanopachys quadricollis (Marseul, 1879) = Stephanopachys quadraticollis
Kocher, 1956, syn. n.peer-reviewe
Peroxygenase-Catalyzed Enantioselective Sulfoxidations
No full textThe performances of the unspecific peroxigenase from Agrocybe aegerita (AaeUPO) in the asymmetric sulfoxidation of substituted aryl alkyl sulfides were here investigated. A small library of differently substituted aryl alkyl sulfoxides was successfully synthesized from the corresponding sulfides in the presence of AaeUPO and H2O2. All the sulfoxides were obtained as (R)-enantiomers, regardless the substitution pattern both on the aromatic ring and the alkyl chain, in up to > 99 % conversion and > 99 % ee. An overview about the biocatalytic entries to chiral sulfoxides is also presented here in form of a comparison between the results obtained with AaeUPO and performances of the chloroperoxidase from Caldariomyces fumago, and three different Baeyer–Villiger monooxygenases. To the best our knowledge, this is the first example of a systematic investigation of the AaeUPO synthetic potential in the asymmetric oxidation of hetero atoms, i.e., the pro-stereogenic sulfur of sulfides
Valorizing Agro-Industrial By-Products for Sustainable Cultivation of Chlorella sorokiniana: Enhancing Biomass, Lipid Accumulation, Metabolites, and Antimicrobial Potential
No full textBackground/Objectives: Mixotrophic cultivation of microalgae using agro-industrial by-products as supplements offers a sustainable strategy to enhance biomass production and bioactive compound synthesis. This study aimed to evaluate the effects of different agro-industrial by-products—orange peel extract, Cladophora glomerata macroalgal hydrolysate, and solid-state fungal fermentation hydrolysate—on the growth and bioactivity of Chlorella sorokiniana. Methods: Microalgae were cultivated under mixotrophic conditions with different agro-industrial by-products as organic carbon sources. Biomass accumulation was monitored through dry weight measurements. Lipid extraction was carried out using dimethyl carbonate. The antimicrobial activity of the extracted compounds was assessed against Escherichia coli, Bacillus megaterium, and Bacillus subtilis by determining the minimal inhibitconcentrations. Results: Orange peel extract supplementation resulted in the highest biomass production. It increased dry weight by 13.86-fold compared to autotrophic conditions. Cladophora glomerata macroalgal hydrolysate followed with a 5.79-fold increase, and solid-state fungal fermentation hydrolysate showed a 4.14-fold increase. The lipophilic fraction extracted from microalgal biomass showed high yields. Orange peel extract supplementation achieved the highest extraction yield (274.36 mg/g DW). Antimicrobial activity varied based on the supplement used: biomass cultivated with orange peel extract exhibited superior activity against E. coli, whereas Cladophora glomerata macroalgal hydrolysate biomass demonstrated potent activity against B. subtilis (MIC: 5.67 g/mL). Conclusions: These findings underscore the potential of agro-industrial by-products for enhancing microalgal biomass and metabolite production. The observed antimicrobial properties highlight the application of microalgal-derived compounds in sustainable bioprocesses, supporting their use in pharmaceutical and biotechnological applications
Statistical approach to discrete-time chotic systems: some tools for studying chaos with densities and application to EMI reduction
No full textThis contribution represents the slides of a tutorial held by the author
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