4,458 research outputs found

    Ciguatoxins

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    Ciguatoxins (CTXs), which are responsible for Ciguatera fish poisoning (CFP), are liposoluble toxins produced by microalgae of the genera Gambierdiscus and Fukuyoa. This book presents 18 scientific papers that offer new information and scientific evidence on: (i) CTX occurrence in aquatic environments, with an emphasis on edible aquatic organisms; (ii) analysis methods for the determination of CTXs; (iii) advances in research on CTX-producing organisms; (iv) environmental factors involved in the presence of CTXs; and (v) the assessment of public health risks related to the presence of CTXs, as well as risk management and mitigation strategies

    Molecular Motor Based on Single Chiral Tripodal Molecules Studied with STM

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    This work presents a single molecular motor driven by the current in an STM. Its chiral functional group is supposed to perform a rotation in a preferred direction, proven by Binomial tests to be statistically significant. The rotation is proposedly driven by the chiral-induced spin selectivity effect (CISS). However, the studies of the rotation on the dependence on the lateral tip position, voltage and current indicate that he CISS is unlikely to cause the preferred rotation direction

    Artificial Intelligence, Robots, and Philosophy

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    This book is a collection of all the papers published in the special issue “Artificial Intelligence, Robots, and Philosophy,” Journal of Philosophy of Life, Vol.13, No.1, 2023, pp.1-146. The authors discuss a variety of topics such as science fiction and space ethics, the philosophy of artificial intelligence, the ethics of autonomous agents, and virtuous robots. Through their discussions, readers are able to think deeply about the essence of modern technology and the future of humanity. All papers were invited and completed in spring 2020, though because of the Covid-19 pandemic and other problems, the publication was delayed until this year. I apologize to the authors and potential readers for the delay. I hope that readers will enjoy these arguments on digital technology and its relationship with philosophy. *** Contents*** Introduction : Descartes and Artificial Intelligence; Masahiro Morioka*** Isaac Asimov and the Current State of Space Science Fiction : In the Light of Space Ethics; Shin-ichiro Inaba*** Artificial Intelligence and Contemporary Philosophy : Heidegger, Jonas, and Slime Mold; Masahiro Morioka*** Implications of Automating Science : The Possibility of Artificial Creativity and the Future of Science; Makoto Kureha*** Why Autonomous Agents Should Not Be Built for War; István Zoltán Zárdai*** Wheat and Pepper : Interactions Between Technology and Humans; Minao Kukita*** Clockwork Courage : A Defense of Virtuous Robots; Shimpei Okamoto*** Reconstructing Agency from Choice; Yuko Murakami*** Gushing Prose : Will Machines Ever be Able to Translate as Badly as Humans?; Rossa Ó Muireartaigh**

    Oxysterols as drivers of inflammatory diseases

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    Antimicrobial Peptides Aka Host Defense Peptides – From Basic Research to Therapy

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    This Special Issue reprint will address the most current and innovative developments in the field of HDP research across a range of topics, such as structure and function analysis, modes of action, anti-microbial effects, cell and animal model systems, the discovery of novel host-defense peptides, and drug development

    Modelling, Monitoring, Control and Optimization for Complex Industrial Processes

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    This reprint includes 22 research papers and an editorial, collected from the Special Issue "Modelling, Monitoring, Control and Optimization for Complex Industrial Processes", highlighting recent research advances and emerging research directions in complex industrial processes. This reprint aims to promote the research field and benefit the readers from both academic communities and industrial sectors

    One-sided differentiability: a challenge for computer algebra systems

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    Computer Algebra Systems (CASs) are extremely powerful and widely used digital tools. Focusing on differentiation, CASs include a command that computes the derivative of functions in one variable (and also the partial derivative of functions in several variables). We will focus in this article on real-valued functions of one real variable. Since CASs usually compute the derivative of real-valued functions as a whole, the value of the computed derivative at points where the left derivative and the right derivative are different (that we will call conflicting points) should be something like "undefined", although this isn't always the case: the output could strongly differ depending on the chosen CAS. We have analysed and compared in this article how some well-known CASs behave when addressing differentiation at the conflicting points of five different functions chosen by the authors. Finally, the ability for calculating one-sided limits of CASs allows to directly compute the result in these cumbersome cases using the formal definition of one-sided derivative, which we have also analysed and compared for the selected CASs. Regarding teaching, this is an important issue, as it is a topic of Secondary Education and nowadays the use of CASs as an auxiliary digital tool for teaching mathematics is very common

    Technological developments in Virtual Screening for the discovery of small molecules with novel mechanisms of action

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    [eng] Advances in structural and molecular biology have favoured the rational development of novel drugs thru structure-based drug design (SBDD). Particularly, computational tools have proven to be rapid and efficient tools for hit discovery and optimization. The main motivation of this thesis is to improve and develop new methods in the area of computer-based drug discovery in order to study challenging targets. Specifically, this thesis is focused on docking and Virtual Screening (VS) methodologies to be able to exploit non-standard sites, like protein-protein interfaces or allosteric sites, and discover bioactive molecules with novel mechanisms of action. First, I developed an automatic pipeline for binding mode prediction that applies knowledge- based restraints and validated the approach by participating in the CELPP Challenge, a blind pose prediction challenge. The aim of the first VS in this thesis is to find small molecules able to not only disrupt the RANK-RANKL interaction but also inhibit the constitutive activation of the receptor. With a combination of computational, biophysical, and cell-based assays we were able to identify the first small molecule binders for RANK that could be used as a treatment for Triple Negative Breast Cancer. When working with challenging targets, or with non-standard mechanisms of action, the relationship between binding and the biological response is unpredictable, because the biological response (if any) will depend on the biological function of the particular allosteric site, which is generally unknown. For this reason, we then tested the applicability of the combination of ultrahigh-throughput VS with low-throughput high content assay. This allowed us to characterize a novel allosteric pocket in PTEN and also describe the first allosteric modulators for this protein. Finally, as the accessible Chemical Space grows at a rapid pace, we developed an algorithm to efficiently explore ultra-large Chemical Collections using a Bottom-up approach. We prospectively validated the approach in BRD4 and identified novel BRD4 inhibitors with an affinity comparable to advanced drug candidates for this target.[cat] Els avenços en biologia estructural i molecular han afavorit el desenvolupament racional de nous fàrmacs a través del disseny de fàrmacs basat en l'estructura (SBDD). En particular, les eines computacionals han demostrat ser ràpides i eficients per al descobriment i l'optimització de fàrmacs. La principal motivació d'aquesta tesi és millorar i desenvolupar nous mètodes en l'àrea del descobriment de fàrmacs per ordinador per tal d'estudiar proteïnes complexes. Concretament, aquesta tesi se centra en les metodologies d'acoblament i de cribratge virtual (CV) per poder explotar llocs no estàndard, com interfícies proteïna-proteïna o llocs al·lostèrics, i descobrir molècules bioactives amb nous mecanismes d'acció. En primer lloc, vaig desenvolupar un protocol automàtic per a la predicció del mode d’unió aplicant restriccions basades en el coneixement i vaig validar l'enfocament participant en el repte CELPP, un repte de predicció del mode d’unió a cegues. L'objectiu del primer CV d'aquesta tesi és trobar petites molècules capaces no només d'interrompre la interacció RANK-RANKL sinó també d'inhibir l'activació constitutiva del receptor. Amb una combinació d'assajos computacionals, biofísics i basats en cèl·lules, vam poder identificar les primeres molècules petites per a RANK que es podrien utilitzar com a tractament per al càncer de mama triple negatiu. Quan es treballa amb proteïnes complexes, o amb mecanismes d'acció no estàndard, la relació entre la unió i la resposta biològica és impredictible, perquè la resposta biològica (si n'hi ha) dependrà de la funció biològica del lloc al·lostèric particular, que generalment és desconeguda. Per aquest motiu, després vam provar l'aplicabilitat de la combinació de CV d'alt rendiment amb assaig de contingut alt de baix rendiment. Això ens va permetre caracteritzar un nou lloc d’unió al·lostèric en PTEN i també descriure els primers moduladors al·lostèrics d'aquesta proteïna. Finalment, a mesura que l'espai químic accessible creix a un ritme ràpid, hem desenvolupat un algorisme per explorar de manera eficient col·leccions de productes químics molt grans mitjançant un enfocament de baix a dalt. Vam validar aquest enfocament amb BRD4 i vam identificar nous inhibidors de BRD4 amb una afinitat comparable als candidats a fàrmacs més avançats per a aquesta proteïna

    Type Synthesis and Performance Optimization of Parallel Manipulators

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    Parallel robots have been widely employed in industrial applications. There are still some challenging topics in the fundamental research, e.g., the primary problem mobility analysis has not been solved for about 150 years. A universal mobility equation for all kinds of parallel architectures has not been found. Another issue lies on the performance measurements for parallel manipulators. There are plenty of kinematic and dynamic performance indices. However, the various ranges and scales of these indicators make the optimal design considering multiple indices complicated. It is essential to search for a unified approach to normalize performance indicators. More dynamic performance measurement indicators should be raised to explore the dynamic features and complete the theory for parallel mechanisms. In this research, an improved mobility equation is designed to reveal the degrees of freedom for a special class of parallel robots. A novel methodology called the kinematic joint matrix is proposed. It possesses the mapping relations with parallel manipulators. A series of 2-6 degrees of freedom parallel architectures is denoted by the kinematic joint matrix. The theory of screw is employed to check the feasibility from several kinds of parallel structures. A special block diagram is introduced to distinguish various kinematic joint matrices. Since this family of parallel robots contains various motion characteristics, four parallel robots with distinct features are selected. Based on the kinematic models, three categories of singularities are explored. The operational and reachable workspaces of the pure-translational parallel robots are searched and the parametric analyses are reported. The linkage’s impacts for the reachable workspace of the mixed-motion parallel architectures are investigated. The novel performance level index is designed to unify the positive performance index and demonstrated the performance rank for any pose (position and orientation). The dexterity index is utilized as an example to verify the characteristics of the level index. The distributions and parametric analyses of two novel mass-related performances are studied. The dimension synthesis of a selected planar parallel robot is presented based on the non-dominated genetic algorithm II. The experiment results testify the correctness of the mobility and kinematic mathematical models of this mechanism

    The sugars content of parental and new perspective descendant strawberry genotypes potential approach for the future selection process

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    Besides being one of the most commercially grown berry fruits, strawberries (Fragaria x annanassa Duch.) are known for their nutritional value, richness in polyphenols, and antioxidant capacity. New directions of strawberry breeding and selection are set towards premium fruit quality, high sugars content, and desirable sugars/total acids ratio (sweet index, SI), which represent some of the main prerequisites for selecting new breeding materials [1]. With this intention, a set of 24 strawberry genotypes was cultivated, including 12 parental varieties and 12 of their descendants - perspective candidates obtained by crossing the parental varieties mentioned above. A total of eleven sugars were quantified using High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). Results implied that glucose, sorbitol, sucrose, and melibiose content were the most important sugars in separating the fruits of parental varieties and their progeny [2]. Results showed that old, parental varieties had a significantly higher content of glucose and sucrose, while new perspective genotypes had higher sorbitol and melibiose content (Fig.2). PCA analysis confirmed that parental (samples 1-12) and descendant genotypes (samples 13-24), could be discriminated according to sugars profile i.e. that these four sugars have an effect on their differentiation (Fig.1). This was in accordance with Mann-Whitney U test results (Fig.2). Fig.1. Principal Component Analysis - The difference between parental and descendant genotypes; score plot (A) – parental samples (PS) 1-12, descendant (DS) samples 13-24, and loading plot (B) – sugar components. Acknowledgments: This work has been supported by the Ministry of Education, Science, Technological Development and Innovation of Republic of Serbia, Contract number: 451-03-47/2023-01/200168 and 451-03-47/2023-01/200288., as well as company “Zeleni hit d.o.o.” from Belgrade, Serbia and “BerryLab” breeding consortium from Italy. References: [1] L. Mazzoni, L. di Vittori, F. Balducci, T.Y. Forbes-Hernandez, F. Giamperi, M. Battino, B. Mezzeti, F. Capocasa, Scientia Horticulturae, 261: 108945 (2019). [2] M. Fotirić Akšić, T. Tosti, M. Sredojević, J. Milivojević, M. Meland, M. Natić, Plants, 8: 205 (2019).Poster: [https://cherry.chem.bg.ac.rs/handle/123456789/5975
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