33 research outputs found

    Antioxidant and antimicrobial activity of Cynara cardunculus extracts

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    The whole, fresh involucral bracts of cardoon, Cynara cardunculus L. (Compositae), were extracted with EtOH and an aqueous suspension of the obtained EtOH extract was partitioned successively with CHCl3, EtOAc and n-BuOH, leaving a residual water extract. All obtained extracts were evaluated for their antioxidant and antimicrobial properties. The antioxidant potential was evaluated using following in vitro methods: FRAP (ferric reducing antioxidant power) assay, and scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Antimicrobial activity was estimated using a microdilution technique against food-borne, mycotoxin producers and human pathogenic bacteria and micromycetes. The following bacteria were tested: Salmonella typhimurium, Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, as well as micromycetes: Aspergillus niger, Aspergillus ochraceus, Aspergillus flavus, Penicillium ochrochloron, Penicillium funiculosum, Trichoderma viride, Fusarium tricinctum and Alternaria alternata. Results showed that all extracts possessed concentration-dependent antioxidant activity. In biological assays, C. cardunculus extracts showed antimicrobial activity comparable with standard antibiotics.This is peer-reviewed version of the folowing article: Kukić, J.; Popović, V.; Petrović, S.; Mucaji, P.; Ćirić, A.; Stojković, D.; Soković, M. Antioxidant and Antimicrobial Activity of Cynara Cardunculus Extracts. Food Chem. 2008, 107 (2), 861–868. [https://doi.org/10.1016/j.foodchem.2007.09.005

    A Note on Emergence in Multi-Agent String Processing Systems

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    We propose a way to define (and, in a certain extent, even to measure) the phenomenon of emergence which appears in a complex system of interacting agents whose global behaviour can be described by a language and whose components (agents) can also be associated with grammars and languages. The basic idea is to identify the "linear composition of behaviours" with "closure under basic operations", such as the AFL (Abstract Families of Languages) operations, which are standard in the theory of formal languages

    Silicon's Second World: Scarcity, Political Indifference and Innovation in Czechoslovak Computing, 1964-1994

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    How societies invent, adopt, adapt, distribute and innovate with computers is an important puzzle for historians of technology, economists, educators and government planners alike. This dissertation examines the developmental path of Czechoslovakia from when its premier computer scientist, Antonín Svoboda, emigrated in 1964 to slightly beyond state dissolution in 1993. An industrialized consumer society with little to consume, as Jaroslav Švelch noted, Czechoslovakia illustrates both the still-understudied history of computing in state socialist societies and the global story of innovation and adaptation in liminal spaces that provide human capital and emerging markets for the West. An alternate modernity emerged in what Martin Müller calls the 'Global East,' constituted by users living in scarcity, skeptical of state and capital power and maintaining the countercultural community values articulated by exponents like Stewart Brand, Ted Nelson and Buckminster Fuller. This work contributes to the ongoing turn in the history of technology away from Silicon Valley-centered narratives of invention toward the maintenance, adaptation and second-order innovation better representative of technological encounters globally. Czech and Slovak computer users are the focus: Their social origins, personal politics, creativity and negotiated autonomy framed the shape of computing in their country. Their stories are told often by themselves-in extensive oral interviews with key scientists, prominent dissidents and black marketeers-and in the pages of their community's magazines, journals and newsletters, in television interviews, in their jokes and ribald songs. Their voices are part of a global chorus of hobbyism, tinkering, maintenance and technological communities informed by scholars like Jaroslav Švelch, Melanie Swalwell, Honghong Tinn, Helena Durnová, Patryk Wasiak, Ksenia Tatarchenko and Nathan Ensmenger

    From fuzzy to annotated semantic web languages

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    The aim of this chapter is to present a detailed, selfcontained and comprehensive account of the state of the art in representing and reasoning with fuzzy knowledge in Semantic Web Languages such as triple languages RDF/RDFS, conceptual languages of the OWL 2 family and rule languages. We further show how one may generalise them to so-called annotation domains, that cover also e.g. temporal and provenance extensions

    Alternating and empty alternating auxiliary stack automata

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    AbstractWe consider variants of alternating auxiliary stack automata and characterize their computational power when the number of alternations is bounded by a constant or unlimited. In this way we get new characterizations of NP, the polynomial hierarchy, PSpace, and bounded query classes like co-DP=NL〈NP[1]〉 and Θ2P=PNP[O(logn)], in a uniform framework

    Epistemic Foundation of Stable Model Semantics

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    Stable model semantics has become a very popular approach for the management of negation in logic programming. This approach relies mainly on the closed world assumption to complete the available knowledge and its formulation has its basis in the so-called Gelfond-Lifschitz transformation. The primary goal of this work is to present an alternative and epistemic-based characterization of stable model semantics, to the Gelfond-Lifschitz transformation. In particular, we show that stable model semantics can be defined entirely as an extension of the Kripke-Kleene semantics. Indeed, we show that the closed world assumption can be seen as an additional source of `falsehood' to be added cumulatively to the Kripke-Kleene semantics. Our approach is purely algebraic and can abstract from the particular formalism of choice as it is based on monotone operators (under the knowledge order) over bilattices only.Comment: 41 pages. To appear in Theory and Practice of Logic Programming (TPLP

    Production of Selected Microbial Metabolites and Energy Using Different Waste Materials

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    Pro zpracování a nakládání s odpadními substráty lze použít řadu postupů a možností. Stále se rozšiřující spektrum metod a technologií umožňuje další využití materiálů a energie ve formě obnovitelných zdrojů. Jedním z řešení pro zpětné získávání některých odpadních materiálů je využití tzv. bílé (průmyslové) biotechnologie, která zahrnuje praktickou aplikaci metabolických aktivit celé řady různých mikroorganizmů včetně jejich specifických biologických drah k produkci látek s vysokou přidanou hodnotou. V předložené práci screeningového typu bylo pro zhodnocení odpadních surovin využito několik druhů mikroorganizmů kultivovaných za různých specifických podmínek včetně kultivace na odpadních materiálech získaných zejména ze zemědělství a potravinářství. Cílem bylo získání vybraných typů průmyslově cenných metabolitů, případně energie. Předložená studie byla zaměřena na srovnání růstu a produkčních vlastností několika kmenů karotenogenních kvasinek rodu Rhodotorula, Sporobolomyces a Cystofilobasidium, kultivovaných v médiích s obsahem glycerolu (technický a odpadní glycerol), dále v médiích obsahujících pšeničnou slámu, hydrolyzovanou slámu zpracovanou v hydrotermálním procesu při vysoké teplotě a zbytky po filtraci hydrolyzátu. Dalším testovaným odpadním substrátem byla syrovátka. Všechny testované kvasinky byly schopny využít glycerol jako jediný zdroj uhlíku. Produkce biomasy při kultivaci na technickém glycerolu se více či méně přibližovala kontrole (cca 7 - 10 gl-1), zatímco při kultivaci na odpadním glycerolu byla produkce vyšší (10.9 - 14.5 gl-1). Produkce karotenoidů a ergosterolu byla vyšší v glukózovém médiu než v médiu s obsahem glycerolu. Všechny testované kvasinky byly rovněž schopny produkovat neutrální lipidy, a to v rozmezí 11 - 15 %, s výjimkou C. capitatum, kde produkce dosahovala více než 22 % obsahu neutrálních lipidů. Pšeničná sláma a produkty z ní připravené se ukázaly být využitelnými substráty s vysokým potenciálem pro produkci biomasy i metabolitů, a to zejména u kmene S. roseus. Syrovátka, jako odpadní produkt mlékarenství, byla účinně využita jako substrát pro kokultivaci karotenogenních kvasinek a bakterií mléčného kvašení. Kokultivační proces může vyvolat nadprodukci pigmentů a ergosterolu, přičemž získaná biomasa díky obohacení o bakterie L. casei dosahovala vyšší kvality. Za účelem energetického využití mikrobiálního metabolismu formou mikrobiálních palivových článků, tzv. „Microbial Fuel Cell“ byla aplikována směsná kultura bakterií získaných z čistírny odpadních vod. Tyto mikroorganizmy hrají významnou roli při výrobě elektrické energie a současně také při čištění odpadních vod. Elektřina je generována přímo z organických látek přítomných v kultivačním médiu a lze ji použít pro provoz čistírny samotné a případně i pro další aplikace.Wide spectrum of different options available for the treatment and management of waste substrates can be used. Variety of methods and technologies available to carry out material and energy recovery originates a number of “recovery paths”. One of the solutions for recovering some waste materials lies in white (or industrial) biotechnology, which involves metabolic activities of a wide range of different microorganisms and their specific biological conversion. In this work several waste materials (mainly obtained from agro-industry) were used in a comparative screening study to evaluate their potential recovery to a valuable metabolites or energy by various microorganisms applied under specific conditions and circumstances. Presented study was focused on a comparison of growth and production properties of several red yeast strains of the genus Rhodotorula, Sporobolomyces and Cystofilobasidium, when cultivated on glycerol media (technical and waste glycerol), on wheat straw media and residues gained after hydrothermal pretreatment and on media enriched with whey. All tested red yeast strains were able to utilize glycerol as the only carbon source. The biomass production, when cultivated on pure technical glycerol, are less or more equal with control (about 7 - 10 gl-1) while in waste glycerolis even higher (10.9 - 14.5 gl-1).Production of carotenoids and ergosterol was better in glucose medium than in medium with glycerol only. All tested red yeast strains were able to produce also neutral lipids, in range of 11–15 % except C.capitatum, which produced more than 22 % of neutral lipids. Further waste products - both fraction after hydrothermal wheat pretreatment process (filter cake and hydrolysate) and untreated wheat straw were utilized for red yeast cultivation. Wheat straw (as well as pretreated materials) has proved to be promise substrate with a bigger potential for biomass and metabolite production, especially in S. roseus strain. Whey, as a surplus product from dairy, can be effectively utilized by synergic activities of carotenogenic yeasts and lactic acid bacteria. Co-cultivation process could lead to overproduction of pigments and ergosterol and, therefore, obtained biomass (enriched also with L. casei bacteria) will increase overall quality. In this thesis, the operating microbe which shall be involved in the process of energy recovery represents a mixture of bacteria obtained from the waste water plant. Those microbes played main role in Microbial Fuel Cell (MFC), producing electrical energy and cleaning waste water at once. Electricity is being generated in a direct way from organic matter and can be used for operation of the waste treatment plant, or sold to the energy market.

    Decomposition orders : another generalisation of the fundamental theorem of arithmetic

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    We discuss unique decomposition in partial commutative monoids. Inspired by a result from process theory, we propose the notion of decomposition order for partial commutative monoids, and prove that a partial commutative monoid has unique decomposition iff it can be endowed with a decomposition order. We apply our result to establish that the commutative monoid of weakly normed processes modulo bisimulation definable in ACPe with linear communication, with parallel composition as binary operation, has unique decomposition. We also apply our result to establish that the partial commutative monoid associated with a well-founded commutative residual algebra has unique decompositio

    Chemical Composition and Biological Activities of Essential Oils

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    Essential oils extracted by the distillation or hydrodistillation of aromatic plants are a complex mixture of volatile compounds with several biological activities. Their efficacy as antimicrobial agents is related to the activity of several natural compounds belonging to different chemical families that can act both in synergy with each other and with other antibiotics. The antibiotic resistance detected among pathogens has been quickly increasing in recent years, and the control of some of these microorganisms is becoming a planetary emergency for human and animal health. The control of the microbial growth is a problem of great importance also for the food industry (food deterioration and shelf life extension) and for the world of cultural heritage (indoor and outdoor phenomena of biodeterioration). Essential oils can play an important role in this scenario, due their recognized broad-spectrum antimicrobial activity. Therefore, the main subject of this Special Issue includes an essential oil-based approach to control microrganisms in areas such as human and veterinary medicine, entomology, food industry and agriculture. In addition, the chemical composition of essential oils from endemic and rare medicinal/aromatic plants, nanoformulations of essential oils, applications in human and veterinary medicine and its use as animal feeding supplements are topics covered in this Special Issu
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