97 results on '"Holub, J."'
Search Results
2. PFP Compressed Suffix Trees
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Boucher, C., Cvacho, O., Gagie, T., Holub, J., Manzini, G., Navarro, G., and Rossi, M.
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Data_CODINGANDINFORMATIONTHEORY ,Article - Abstract
Prefix-free parsing (PFP) was introduced by Boucher et al. (2019) as a preprocessing step to ease the computation of Burrows-Wheeler Transforms (BWTs) of genomic databases. Given a string S, it produces a dictionary D and a parse P of overlapping phrases such that BWT(S) can be computed from D and P in time and workspace bounded in terms of their combined size |PFP(S)|. In practice D and P are significantly smaller than S and computing BWT(S) from them is more efficient than computing it from S directly, at least when S is the concatenation of many genomes. In this paper, we consider PFP(S) as a data structure and show how it can be augmented to support full suffix tree functionality, still built and fitting within O(|PFP(S)|) space. This entails the efficient computation of various primitives to simulate the suffix tree: computing a longest common extension (LCE) of two positions in S; reading any cell of its suffix array (SA), of its inverse (ISA), of its BWT, and of its longest common prefix array (LCP); and computing minima over ranges and next/previous smaller value queries over the LCP. Our experimental results show that the PFP suffix tree can be efficiently constructed for very large repetitive datasets and that its operations perform competitively with other compressed suffix trees that can only handle much smaller datasets.
- Published
- 2021
3. Face-Fusion of Icosahedral Boron Hydride Increases Affinity to γ-Cyclodextrin: closo,closo-[B21H18]− as an Anion with Very Low Free Energy of Dehydration
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Assaf, K. I., Holub, J., Bernhardt, E., Oliva, José M., Fernández Pérez, M. I., Canle, M., Santaballa, J. A., Fanfrlík, J., Hnyk, D., Nau, W. M., German Research Foundation, Czech Science Foundation, Xunta de Galicia, and Ministerio de Ciencia, Innovación y Universidades (España)
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Anion binding ,Intermolecular interactions ,Boron clusters ,Desolvation ,Host-guest chemistry - Abstract
6 pags., 5 figs., 1 tab., The supramolecular recognition of closo,closo-[BH] by cyclodextrins (CDs) has been studied in aqueous solution by isothermal titration calorimetry and nuclear magnetic resonance spectroscopy. These solution studies follow up on previous mass-spectrometric measurements and computations, which indicated the formation and stability of CD ⋅ BH complexes in the gas phase. The thermodynamic signature of solution-phase binding is exceptional, the association constant for the γ-CD complex with BH reaches 1.8×10 M, which is on the same order of magnitude as the so far highest observed value for the complex between γ-CD and a metallacarborane. The nature of the intermolecular interaction is also examined by quantum-mechanical computational protocols. These suggest that the desolvation penalty, which is particularly low for the BH anion, is the decisive factor for its high binding strength. The results further suggest that the elliptical macropolyhedral boron hydride is another example of a CD binder, whose extraordinary binding affinity is driven by the chaotropic effect, which describes the intrinsic affinity of large polarizable and weakly solvated chaotropic anions to hydrophobic cavities and surfaces in aqueous solution., K.I.A. and W.M.N. are grateful to the DFG for grant NA-686/8within the priority program SPP 1807 “Control of London Dispersion Interactions in Molecular Chemistry”. J.H., J.F., and D.H.thank the Czech Science Foundation (grant number 17-08045S) and M.I.F.P., M.C.L, and J.A.S.L. thank the regional government Xunta de Galicia for financial support (Project Grupo Potencial Crecemento -GPC- ED431B 2017/59). J.M.O.-E. acknowledgesfinancial support from the Spanish MICINN through project CTQ2018-094644-B-C22
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- 2020
4. Photochromic System among Boron Hydrides: The Hawthorne Rearrangement
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Francés-Monerris, A., Holub, J., Roca-Sanjuán, D., Hnyk, D., Lang, K., Oliva, José M., Francés-Monerris, A., Holub, J., Roca-Sanjuán, D., Hnyk, D., Lang, K., and Oliva, José M.
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Photoswitchable molecules have attracted wide interest for many applications in chemistry, physics, and materials science. In this work, we revisit the reversible photochemical and thermal rearrangements of the two BH isomers reported by Hawthorne and Pilling in 1966, whose mechanism had not been understood so far. We investigate the rearrangements by means of a joint experimental and computational study with the outcome that BH represents the first boron-based photochromic system ever reported. Both photochemical and thermal isomerizations occur through the same intermediate and involve a diamond-square-diamond (DSD) mechanism. Given the absence within boron chemistry of named chemical reactions as opposed to organic chemistry, we propose to label the BH photo- A nd thermal isomerization processes as the Hawthorne rearrangement.
- Published
- 2019
5. Predicted Gas-Phase and Liquid-Phase Acidities of Carborane Carboxylic and Dicarboxylic Acids
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Oliva, José M., Humbel, S., Santaballa, J.A., Alkorta, Ibon, Notario, Rafael, Dávalos, J.Z., Canle-L., M., Bernhardt, E., Holub, J., Hnyk, D., Oliva, José M., Humbel, S., Santaballa, J.A., Alkorta, Ibon, Notario, Rafael, Dávalos, J.Z., Canle-L., M., Bernhardt, E., Holub, J., and Hnyk, D.
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By means of MP2 and DFT computations we predict gas-phase acidities and liquid-phase (MeCN) acidities of (di)carboxylic acids derived from icosahedral ortho, meta, and para-carboranes. For comparative purpose, we include the benzoic and phthalic acids. Substitution of benzene by a carborane cage – cage effect – strikingly increases the gas-phase acidity (lower GA) for the (di)carboxylic acids, being the ortho isomers always the most acidic, following the order ortho ≫ meta > para. The computed GA of the dicarboxylic acid derived from ortho-carborane is far lower than sulphuric acid, due to an enhanced stabilization of the carboxylate through an intramolecular OHO bridge connection, also taking place in phthalic acid. The change of GA relative to ortho, meta and para positions of the carboxylic groups - isomer effect - is larger for carboranes. As regards to liquid-phase (MeCN), the computations show that carborane (di)carboxylic acids also show a larger acidity (lower pK) as compared to the phthalic acids and that the dicarboxylic ortho-carborane is also a superacid in the liquid phase (MeCN), due to the OHO bridge connection in the carboxylate, as in the gas phase. Additional computations show how much of this isomeric effect is to be attributed to the electronic delocalization.
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- 2018
6. Many-MADFAct: concurrently constructing MADFAs
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Runge, T., Schaefer, I., Cleophas, L.G.W.A., Watson, B.W., Holub, J., and Zdarek, J.
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Minimal acyclic deterministic finite automata (MADFAs) are used to represent dictionaries, i.e., finite sets of finite words, in, e.g., spell checkers and network security applications. Given the size of such dictionaries, which may contain millions of words, their efficient construction is a critical issue. Watson (2010) published a classification of such algorithms in an algorithm taxonomy with correctness arguments. We report on a new algorithm which constructs MADFAs in parallel---each for a keyword set from a partition of the original keyword set---and afterwards merges and minimizes the resulting automata into a single MADFA; on our experience implementing the algorithms in a Java-based toolkit; and on empirical performance results obtained.
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- 2017
7. Concerning biorthogonal systems in C(S)
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Holub, J. R., additional
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- 2017
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8. Reconstructing a string from its Lyndon arrays
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Daykin, J.W., Franěk, F., Holub, J., Islam, A.S.M.S., Smyth, W.F., Daykin, J.W., Franěk, F., Holub, J., Islam, A.S.M.S., and Smyth, W.F.
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Given a string x=x[1..n]x=x[1..n] on an ordered alphabet Σ of size σ , the Lyndon array λ=λx[1..n]λ=λx[1..n] of x is an array of positive integers such that View the MathML sourceλ[i],1≤i≤n, is the length of the maximal Lyndon word over the ordering of Σ that begins at position i in x . The Lyndon array has recently attracted considerable attention due to its pivotal role in establishing the long-standing conjecture that ρ(n)
- Published
- 2017
9. Emotion models for textual emotion classification
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Bruna, O., primary, Avetisyan, H., additional, and Holub, J., additional
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- 2016
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10. Overview of existing algorithms for emotion classification. Uncertainties in evaluations of accuracies.
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Avetisyan, H, primary, Bruna, O, additional, and Holub, J, additional
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- 2016
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11. Quantum leap pattern matching
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Watson, B.W., Kourie, D.G., Cleophas, L., Holub, J., and Žďárek, J.
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Quantum leap matching is introduced as a generic pattern matching strategy for the single keyword exact pattern matching problem, that can be used on top of existing Boyer-Moore-style string matching algorithms. The cost of the technique is minimal: an additional shift table (of one dimension, for shifts in the opposite direction to the parent algorithm’s shifts), and the replacement of a simple table lookup assignment statement in the original algorithm with a similar conditional assignment. Together with each of the conventional shift table lookups, the additional shift table is typically also indexed on the text character that is at a distance of z away from the current sliding window. Under conditions that are identified, the returned values from the two shift tables allow a “quantum leap” of distance more than the length of the keyword for the next matching attempt. If the conditions are not met, then there is a fall back is to the traditional shift. Quick Search (by Sunday) is used as a case study to illustrate the technique. The performance of the derived “Quantum Leap Quick Search” algorithm is compared against Quick Search. When searching for shorter patterns over natural language and genomic texts, the technique improves on Quick Search’s time for most values of z. Improvements are also sometimes seen for various values of z on larger patterns. Most interestingly, under best case conditions it performs, on average, at about three times faster than Quick Search.
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- 2015
12. Development and implementation of data collection technologies for digital mapping of soil electric conductivity.
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Kroulik, M., Zabransky, P., Holub, J., and Chyba, J.
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SOIL protection ,ENVIRONMENTAL protection ,SOIL remediation ,SUSTAINABLE agriculture ,ELECTRIC conductivity - Abstract
One of the main preconditions for the introduction of soil protection measures and sustainable use of a soil is to strengthen the knowledge base about the specific habitats characteristics with high spatial resolution and adequate interventions to these properties. One of the most common sensors used to describe the level of soil variability are devices that measure the electric conductivity of the soil. Platform for the electrical conductivity measuring has been developed and implemented into the standard combined machines for the tillage and seeding, using an existing work tools as part of the platform. Within the field work the series of measurements was conducted with this machine and platform and data of electrical conductivity were collected. On the same field as a reference method electrical conductivity was measured by an electromagnetic induction probe EM38 MK2. Compared data from the measuring platform and the EM38 MK2 probe showed a high correlation value. The experiments demonstrate the possibilities of technical solutions of soil conductivity measurement implementation on tillage and seeding machines where by a modification of selected tillage and seeding machines together with incorporation of sensors directly onto the work tools is possible to obtain measuring platform that enables data collection directly during operation of the machine on the field. [ABSTRACT FROM AUTHOR]
- Published
- 2017
13. Covalent Triazine-Based Frameworks with Ru-tda Based Catalyst Anchored via Coordination Bond for Photoinduced Water Oxidation.
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Salati M, Dorchies F, Wang JW, Ventosa M, González-Carrero S, Bozal-Ginesta C, Holub J, Rüdiger O, DeBeer S, Gimbert-Suriñach C, Durrant JR, Ertem MZ, Gil-Sepulcre M, and Llobet A
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Light-induced water splitting (hν-WS) for the production of hydrogen as a solar fuel is considered a promising sustainable strategy for the replacement of fossil fuels. An efficient system for hν-WS involves a photoactive material that, upon shining light, is capable of separating and transferring charges to catalysts for the hydrogen and oxygen evolution processes. Covalent triazine-based frameworks (CTFs) represent an interesting class of 2D organic light-absorbing materials that have recently emerged thanks to their tunable structural, optical and morphological properties. Typically, catalysts (Cat) are metallic nanoparticles generated in situ after photoelectroreduction of metal precursors or directly drop-casted on top of the CTF material to generate Cat-CTF assemblies. In this work, the synthesis, characterization and photocatalytic performance of a novel hybrid material, Ru-CTF, is reported, based on a CTF structure featuring dangling pyridyl groups that allow the Ru-tda (tda is [2,2':6',2'"-terpyridine]-6,6'"-dicarboxylic acid) water oxidation catalyst (WOC) unit to coordinate via covalent bond. The Ru-CTF molecular hybrid material can carry out the light-induced water oxidation reaction efficiently at neutral pH, reaching values of maximum TOF of 17 h
-1 and TONs in the range of 220 using sodium persulfate as a sacrificial electron acceptor., (© 2024 Wiley‐VCH GmbH.)- Published
- 2024
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14. Taxonomic classification with maximal exact matches in KATKA kernels and minimizer digests.
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Draesslerová D, Ahmed O, Gagie T, Holub J, Langmead B, Manzini G, and Navarro G
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For taxonomic classification, we are asked to index the genomes in a phylogenetic tree such that later, given a DNA read, we can quickly choose a small subtree likely to contain the genome from which that read was drawn. Although popular classifiers such as Kraken use k -mers, recent research indicates that using maximal exact matches (MEMs) can lead to better classifications. For example, we can ■ build an augmented FM-index over the the genomes in the tree concatenated in left-to-right order; ■ for each MEM in a read, find the interval in the suffix array containing the starting positions of that MEM's occurrences in those genomes; ■ find the minimum and maximum values stored in that interval; ■ take the lowest common ancestor (LCA) of the genomes containing the characters at those positions. This solution is practical, however, only when the total size of the genomes in the tree is fairly small. In this paper we consider applying the same solution to three lossily compressed representations of the genomes' concatenation: ■ a KATKA kernel, which discards characters that are not in the first or last occurrence of any k max -tuple, for a parameter k max ; a minimizer digest; ■ a KATKA kernel of a minimizer digest. With a test dataset and these three representations of it, simulated reads and various parameter settings, we checked how many reads' longest MEMs occurred only in the sequences from which those reads were generated ("true positive" reads). For some parameter settings we achieved significant compression while only slightly decreasing the true-positive rate.
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- 2024
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15. The PAX LC Trial: A Decentralized, Phase 2, Randomized, Double-Blind Study of Nirmatrelvir/Ritonavir Compared with Placebo/Ritonavir for Long COVID.
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Krumholz HM, Sawano M, Bhattacharjee B, Caraballo C, Khera R, Li SX, Herrin J, Coppi A, Holub J, Henriquez Y, Johnson MA, Goddard TB, Rocco E, Hummel AC, Al Mouslmani M, Putrino DF, Carr KD, Carvajal-Gonzalez S, Charnas L, De Jesus M, Ziegler FW 3rd, and Iwasaki A
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Background: Individuals with long COVID lack evidence-based treatments and have difficulty participating in traditional site-based trials. Our digital, decentralized trial investigates the efficacy and safety of nirmatrelvir/ritonavir, targeting viral persistence as a potential cause of long COVID., Methods: The PAX LC trial (NCT05668091) is a Phase 2, 1:1 randomized, double-blind, superiority, placebo-controlled trial in 100 community-dwelling, highly symptomatic adult participants with long COVID residing in the 48 contiguous US states to determine the efficacy, safety, and tolerability of 15 days of nirmatrelvir/ritonavir compared with placebo/ritonavir. Participants are recruited via patient groups, cultural ambassadors, and social media platforms. Medical records are reviewed through a platform facilitating participant-mediated data acquisition from electronic health records nationwide. During the drug treatment, participants complete daily digital diaries using a web-based application. Blood draws for eligibility and safety assessments are conducted at or near participants' homes. The study drug is shipped directly to participants' homes. The primary endpoint is the PROMIS-29 Physical Health Summary Score difference between baseline and Day 28, evaluated by a mixed model repeated measure analysis. Secondary endpoints include PROMIS-29 (Mental Health Summary Score and all items), Modified GSQ-30 with supplemental symptoms questionnaire, COVID Core Outcome Measures for Recovery, EQ-5D-5L (Utility Score and all items), PGIS 1 and 2, PGIC 1 and 2, and healthcare utilization. The trial incorporates immunophenotyping to identify long COVID biomarkers and treatment responders., Conclusion: The PAX LC trial uses a novel decentralized design and a participant-centric approach to test a 15-day regimen of nirmatrelvir/ritonavir for long COVID., (Copyright © 2024. Published by Elsevier Inc.)
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- 2024
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16. Methylmercury Effect and Distribution in Two Extremophile Microalgae Strains Dunaliella salina and Coccomyxa onubensis from Andalusia (Spain).
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Simansky S, Holub J, Márová I, Cuaresma M, Garbayo I, Torronteras R, Vílchez C, and Gojkovic Z
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The main entrance point of highly toxic organic Hg forms, including methylmercury (MeHg), into the aquatic food web is phytoplankton, which is greatly represented by various natural microalgal species. Processes associated with MeHg fate in microalgae cells such as uptake, effects on cells and toxicity, Hg biotransformation, and intracellular stability are detrimental to the process of further biomagnification and, as a consequence, have great importance for human health. The study of MeHg uptake and distribution in cultures of marine halophile Dunaliella salina and freshwater acidophilic alga Coccomyxa onubensis demonstrated that most of the MeHg is imported inside the cell, while cell surface adhesion is insignificant. Almost all MeHg is removed from the culture medium after 72 h. Significant processes in rapid MeHg removal from liquid medium are its abiotic photodegradation and volatilization associated with algal enzymatic activity. The maximum intracellular accumulation for both species was in 80 nM MeHg-exposed cultures after 24 h of exposure for D. salina (from 27 to 34 µg/g
DW ) and at 48 h for C. onubensis (up to 138 µg/gDW ). The different Hg intakes in these two strains could be explained by the lack of a rigid cell wall in D. salina and the higher chemical ability of MeHg to pass through complex cell wall structures in C. onubensis . Electron microscopy studies on the ultrastructure of both strains demonstrated obvious microvacuolization in the form of many very small vacuoles and partial cell membrane disruption in 80 nM MeHg-exposed cultures. Results further showed that Coccomyxa onubensis is a good candidate for MeHg-contaminated water reclamation due to its great robustness at nanomolar concentrations of MeHg coupled with its very high intake and almost complete Hg removal from liquid medium at the MeHg levels tested.- Published
- 2024
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17. Employment of chiral columns with superficially porous particles in chiral separations of cobalt bis (dicarbollide) and nido-7,8-C 2 B 9 H 12 (1-) derivatives.
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Horáček O, Dhaubhadel U, Holub J, Grüner B, Armstrong DW, and Kučera R
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Derivatives of the nido-7,8-C
2 B9 H12 (1-) (dicarbollide ion) and [3,3'-Co-(1,2-C2 B9 H11 )2 ](1-) cobalt sandwich (COSAN) ion represent groups of extremely chemically and thermally stable abiotic compounds. They are being investigated in many research areas, that is, medicinal chemistry, material sciences, analytical chemistry, and electrochemistry. The chirality of these compounds remains still grossly overlooked, what is also reflected in limited number of reports on their chiral separations. Continued progress depends on reliable, fast, and cost-effective methods for such separations. Recently, chiral separations of COSAN derivatives were achieved in liquid chromatography and supercritical fluid chromatography. Only five anionic derivatives of nido-7,8-C2 B9 H12 (1-) were successfully enantioseparated in liquid chromatography. Efforts to separate anionic nido-7,8-C2 B9 H12 (1-) in supercritical chromatography have failed, and only a few dicarbollide ions were separated using liquid chromatography. Generally, all chiral separations in liquid chromatography took about 30 min. Herein, we identify a versatile column capable of separating both COSAN and nido-7,8-C2 B9 H12 (1-) derivatives and achieve faster analyses times employing commercially available superficially porous chiral stationary phases. The semisynthetic hydroxypropyl β-cyclodextrin-based column (CDShell-RSP) is identified as the column of choice from the tested columns by separating 19 of 27 compounds from each structural motifs tested mainly in less than 10 min. The dihydroxyalkyl, oxygen-bridged hydroxyalkyl, and bisphenylene-bridged COSAN derivatives were baseline separated in less than 5 min exceeding the results of supercritical fluid chromatography. Methods developed herein will aid synthetic chemists without the possession of a supercritical fluid chromatograph to achieve fast chiral separations of COSAN and derivatives of nido-7,8-C2 B9 H12 (1-) on a common liquid chromatograph without the need of dedicated instrumentation., (© 2023 The Authors. Chirality published by Wiley Periodicals LLC.)- Published
- 2023
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18. Molecular Characterization of a Novel Enamovirus Infecting Raspberry.
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Koloniuk I, Fránová J, Přibylová J, Sarkisova T, Špak J, Tan JL, Zemek R, Čmejla R, Rejlová M, Valentová L, Sedlák J, Holub J, Skalík J, Blystad DR, Sapkota B, and Hamborg Z
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- Animals, Phylogeny, Plant Diseases, Rubus, Luteoviridae genetics, Viruses, Aphids
- Abstract
Raspberry plants, valued for their fruits, are vulnerable to a range of viruses that adversely affect their yield and quality. Utilizing high-throughput sequencing (HTS), we identified a novel virus, tentatively named raspberry enamovirus 1 (RaEV1), in three distinct raspberry plants. This study provides a comprehensive characterization of RaEV1, focusing on its genomic structure, phylogeny, and possible transmission routes. Analysis of nearly complete genomes from 14 RaEV1 isolates highlighted regions of variance, particularly marked by indel events. The evidence from phylogenetic and sequence analyses supports the classification of RaEV1 as a distinct species within the Enamovirus genus. Among the 289 plant and 168 invertebrate samples analyzed, RaEV1 was detected in 10.4% and 0.4%, respectively. Most detections occurred in plants that were also infected with other common raspberry viruses. The virus was present in both commercial and wild raspberries, indicating the potential of wild plants to act as viral reservoirs. Experiments involving aphids as potential vectors demonstrated their ability to acquire RaEV1 but not to successfully transmit it to plants.
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- 2023
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19. Mononuclear or Coordination Polymer Complexes? Both Are Possible for 3,6,9-Trioxaundecanedioic Acid.
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Bella G, Holub J, Bruno G, Nicolò F, and Santoro A
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Investigating the driving forces leading to the formation of a specific supramolecular architecture among a wide spectrum of all the possibly obtainable structures is not an easy task. The contemporary literature provides several models for correctly predicting the thermodynamically accessible structures that can originate from a library of building blocks. Definitions are rigid by their very nature, so their application may sometimes require a shift in perspective. In the study presented herein, we describe the crystal structures of three metallo-supramolecular architectures assembled from deprotonated derivatives of 3,6,9-trioxaundecanedioic acid and Mn(II), Co(II) and Zn(II). In the Mn(II) case, the complexation resulted in a complex of a discrete/heptacoordinated nature, whereas the other two structures appeared as helical polymers. To explain such an anomaly, in this work, we describe how the interplay between the flexibility of the ligand spacer and the number of coordinating atoms involved determines the divergent or convergent organisation of the final coordination architecture.
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- 2023
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20. Boron-based octahedral dication experimentally detected: DFT surface confirms its availability.
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Keller W, Sárosi MB, Fanfrlík J, Straka M, Holub J, McKee ML, and Hnyk D
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Borane and heteroborane clusters have been known as neutral or anionic species. In contrast to them, several ten-vertex monocationic nido and closo dicarbaborane-based systems have recently emerged from the reaction of the parent bicapped-square antiprismatic dicarbaboranes with N-heterocyclic carbenes followed by the protonization of the corresponding nido intermediates. The expansion of these efforts has afforded the very first closo -dicationic octahedral phosphahexaborane along with new closo- monocationic pnictogenahexaboranes of the same shapes. All are the products of the one-pot procedure that consists in the reaction of the same carbenes with the parent closo -1,2-Pn
2 B4 Br4 (Pn = As, P). Whereas in the case of phosphorus such a monocation appears to be a mixture of stable intermediates, and arsenahexaboranyl monocation has occurred as the final product, all of them without using any subsequent reaction. The well-established DFT/ZORA/NMR approach has unambiguously confirmed the existence of these species in solution, and computed electrostatic potentials have revealed the delocalization of the positive charge in these monocations and in the very first dication, namely within the octahedral shapes in both cases., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2023
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21. The Effect of Oil-Rich Food Waste Substrates, Used as an Alternative Carbon Source, on the Cultivation of Microalgae-A Pilot Study.
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Sniegoňová P, Szotkowski M, Holub J, Sikorová P, and Márová I
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Microalgae are mostly phototrophic microorganisms present worldwide, showcasing great adaptability to their environment. They are known for producing essential metabolites such as carotenoids, chlorophylls, sterols, lipids, and many more. This study discusses the possibility of the mixotrophic abilities of microalgae in the presence of food waste oils. The utilization of food waste materials is becoming more popular as a research subject as its production grows every year, increasing the environmental burden. In this work, waste frying oil and coffee oil were tested for the first time as a nutrition source for microalgae cultivation. Waste frying oil is produced in large amounts all over the world and its simple purification is one of its greatest advantages as it only needs to be filtered from leftover food pieces. Coffee oil is extracted from waste spent coffee grounds as a by-product. The waste frying oil and coffee oil were added to the basic algal media as an alternative source of carbon. As a pilot study for further experimentation, the effect of oil in the medium, algal adaptability, and capability to survive were tested within these experiments. The growth and production characteristics of four algae and cyanobacteria strains were tested, of which the strain Desmodesmus armatus achieved exceptional results of chlorophyll (8.171 ± 0.475 mg/g) and ubiquinone (5.708 ± 0.138 mg/g) production. The strain Chlamydomonas reindhartii showed exceptional lipid accumulation in the range of 30-46% in most of the samples.
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- 2023
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22. Wide Variability in Dysplasia Detection Rate and Adherence to Seattle Protocol and Surveillance Recommendations in Barrett's Esophagus: A Population-Based Analysis Using the GIQuIC National Quality Benchmarking Registry.
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Kolb JM, Davis C, Williams JL, Holub J, Shaheen N, and Wani S
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- Humans, Benchmarking, Esophagoscopy, Hyperplasia, Registries, Barrett Esophagus diagnosis, Barrett Esophagus pathology, Esophageal Neoplasms pathology
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Introduction: Variability in adherence rates to the Seattle protocol and to surveillance interval recommendations, established quality indicators (QIs) in Barrett's esophagus (BE), is unknown., Methods: We evaluated endoscopist and site-based adherence rates to these QIs from January 2018 to May 2021 using the GI Quality Improvement Consortium national registry with matched endoscopy and pathology data., Results: Across 153 practices with 572 endoscopists performing 20,155 endoscopies, adherence to the Seattle protocol varied by endoscopists (median 93.8%, IQR 18.9%) and by site (median 90.0%, IQR 20.1%). Adherence to appropriate surveillance intervals for nondysplastic BE also varied by endoscopist (median 82.4%, IQR 36.3%) and site (median 77.2%, IQR 29.8%). The overall dysplasia detection rate was 3.1% and varied among endoscopists and sites., Discussion: These US population-based results can serve as a benchmark for quality initiatives and intervention trials aimed at improving outcomes for patients with BE., (Copyright © 2022 by The American College of Gastroenterology.)
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- 2023
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23. DFT Surface Infers Ten-Vertex Cationic Carboranes from the Corresponding Neutral closo Ten-Vertex Family: The Computed Background Confirming Their Experimental Availability.
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McKee ML, Vrána J, Holub J, Fanfrlík J, and Hnyk D
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Modern computational protocols based on the density functional theory (DFT) infer that polyhedral closo ten-vertex carboranes are key starting stationary states in obtaining ten-vertex cationic carboranes. The rearrangement of the bicapped square polyhedra into decaborane-like shapes with open hexagons in boat conformations is caused by attacks of N-heterocyclic carbenes (NHCs) on the closo motifs. Single-point computations on the stationary points found during computational examinations of the reaction pathways have clearly shown that taking the "experimental" NHCs into account requires the use of dispersion correction. Further examination has revealed that for the purposes of the description of reaction pathways in their entirety, i.e., together with all transition states and intermediates, a simplified model of NHCs is sufficient. Many of such transition states resemble in their shapes those that dictate Z -rearrangement among various isomers of closo ten-vertex carboranes. Computational results are in very good agreement with the experimental findings obtained earlier.
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- 2023
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24. Conversion of Mixed Waste Food Substrates by Carotenogenic Yeasts of Rhodotorula sp. Genus.
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Szotkowski M, Plhalová Ž, Sniegoňová P, Holub J, Chujanov O, Špačková D, Blažková J, and Márová I
- Abstract
The consequence of the massive increase in population in recent years is the enormous production of mainly industrial waste. The effort to minimize these waste products is, therefore, no longer sufficient. Biotechnologists, therefore, started looking for ways to not only reuse these waste products, but also to valorise them. This work focuses on the biotechnological use and processing of waste oils/fats and waste glycerol by carotenogenic yeasts of the genus Rhodotorula and Sporidiobolus . The results of this work show that the selected yeast strains are able to process waste glycerol as well as some oils and fats in a circular economy model and, moreover, are resistant to potential antimicrobial compounds present in the medium. The best-growing strains, Rhodotorula toruloides CCY 062-002-004 and Rhodotorula kratochvilovae CCY 020-002-026, were selected for fed-batch cultivation in a laboratory bioreactor in a medium containing a mixture of coffee oil and waste glycerol. The results show that both strains were able to produce more than 18 g of biomass per litre of media with a high content of carotenoids (10.757 ± 1.007 mg/g of CDW in R. kratochvilovae and 10.514 ± 1.520 mg/g of CDW in R. toruloides , respectively). The overall results prove that combining different waste substrates is a promising option for producing yeast biomass enriched with carotenoids, lipids, and beta-glucans.
- Published
- 2023
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25. Two Shared Icosahedral Metallacarboranes through Iron: A Joint Experimental and Theoretical Refinement of Mössbauer Spectrum in [Fe(1,2-C 2 B 9 H 11 ) 2 ]Cs.
- Author
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Marco JF, Dávalos-Prado JZ, Hnyk D, Holub J, Oña OB, Alcoba DR, Ferrer M, Elguero J, Lain L, Torre A, and Oliva-Enrich JM
- Abstract
Mössbauer and X-ray photoelectron spectroscopies (XPS) are complemented with high-level quantum-chemical computations in the study of the geometric and electronic structure of the paramagnetic salt of the metallacarborane sandwich complex [Fe(1,2-C
2 B9 H11 )2 ]Cs = FeSanCs. Experimental57 Fe isomer shifts and quadrupole splitting parameters are compared with the theoretical prediction, with good agreement. The appearance of two sets of Cs(3d) doublets in the XPS spectrum, separated by 2 eV, indicates that Cs has two different chemical environments due to ease of the Cs(+) cation moving around the sandwich complex with low-energy barriers, as confirmed by quantum-chemical computations. Several minimum-energy geometries of the FeSanCs structure with the corresponding energies and Mössbauer parameters are discussed, in particular the atomic charges and spin population and the surroundings of the Fe atom in the complex. The Mössbauer spectra were taken at different temperatures showing the presence of a low-spin Fe atom with S = 1/2 and thus confirming a paramagnetic FeIII species., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)- Published
- 2023
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26. Rearrangement of dicarboranyl methyl cation to icosahedral C 3 B 9 H 12 + : An ab initio dynamics view.
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Perumalla DS, Ghorai S, Pal T, Hnyk D, Holub J, and Jemmis ED
- Abstract
Closo-carborane anions are prominent, whereas the cations of the same are less abundant in the literature. As these ions have similar size and are weakly coordinating, the ionic liquids of these two ions could have important applications in many areas of chemistry. In view of limited number of polyhedral carborane cations available, we revisited the rearrangement of dicarboranyl methyl cation (7-CH
2 7,9-nido-C2 B9 H10 + ) using ab initio molecular dynamics calculations with metadynamics. Our simulations confirmed the concerted mechanism of the rearrangement. We believe this work will resume the interest in its synthesis and carborane cations in general., (© 2022 Wiley Periodicals LLC.)- Published
- 2023
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27. Production of Enriched Biomass by Carotenogenic Yeasts Cultivated on by-Products of Poultry Processing-A Screening Study.
- Author
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Holub J, Szotkowski M, Chujanov O, Špačková D, Sniegoňová P, and Márová I
- Abstract
Carotenogenic yeasts are a group of microorganisms producing valuable metabolites such as carotenoids, ergosterol, ubiquinone or fatty acids. Their exceptional adaptability allows them to grow in diverse conditions. Owing to their extracellular lipase activity, they are capable of processing many lipid-type waste substrates. This study discusses the processing of poultry waste, specifically fat and feathers by using carotenogenic yeasts. Poultry fat does not require any pre-treatment to be utilized by yeast, but hydrolytic pre-treatment is required for the utilization of the nitrogen contained in feathers. Glycerol was used as a supplementary substrate to support the culture in the early stages of growth. Seven yeast strains were used for the experiments, of which the strain Rhodotorula mucilaginosa CCY19-4-25 achieved exceptional results of biomass production: 29.5 g/L on poultry fat + 10% glycerol at C/N ratio 25 and 28.3 g/L on media containing poultry fat + 25% glycerol at C/N 50. The bioreactor cultivation of the Rhodosporidium toruloides strain in media containing glycerol and feather hydrolysate as a nitrogen substrate achieved a biomass yield of 34.92 g/L after 144 h of cultivation. The produced enriched yeast biomass can be used as a component for poultry feeding; thus, the study is performed under the biorefinery concept.
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- 2023
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28. B-H⋯π and C-H⋯π interactions in protein-ligand complexes: carbonic anhydrase II inhibition by carborane sulfonamides.
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Fanfrlík J, Brynda J, Kugler M, Lepšík M, Pospíšilová K, Holub J, Hnyk D, Nekvinda J, Grüner B, and Řezáčová P
- Subjects
- Ligands, Sulfanilamide, Crystallography, X-Ray, Sulfonamides, Carbonic Anhydrase II
- Abstract
Among non-covalent interactions, B-H⋯π and C-H⋯π hydrogen bonding is rather weak and less studied. Nevertheless, since both can affect the energetics of protein-ligand binding, their understanding is an important prerequisite for reliable predictions of affinities. Through a combination of high-resolution X-ray crystallography and quantum-chemical calculations on carbonic anhydrase II/carborane-based inhibitor systems, this paper provides the first example of B-H⋯π hydrogen bonding in a protein-ligand complex. It shows that the B-H⋯π interaction is stabilized by dispersion, followed by electrostatics. Furthermore, it demonstrates that the similar C-H⋯π interaction is twice as strong, with a slightly smaller contribution of dispersion and a slightly higher contribution of electrostatics. Such a detailed insight will facilitate the rational design of future protein ligands, controlling these types of non-covalent interactions.
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- 2023
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29. Metamorphic oxygen-evolving molecular Ru and Ir catalysts.
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Vereshchuk N, Gil-Sepulcre M, Ghaderian A, Holub J, Gimbert-Suriñach C, and Llobet A
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- Ligands, Oxidation-Reduction, Water chemistry, Catalysis, Protons, Oxygen chemistry
- Abstract
Today sustainable and clean energy conversion strategies are based on sunlight and the use of water as a source of protons and electrons, in a similar manner as it happens in Photosystem II. To achieve this, the charge separation state induced by light has to be capable of oxidising water by 4 protons and 4 electrons and generating molecular oxygen. This oxidation occurs by the intermediacy of a catalyst capable of finding low-energy pathways via proton-coupled electron transfer steps. The high energy involved in the thermodynamics of water oxidation reaction, coupled with its mechanistic complexity, is responsible for the difficulty of discovering efficient and oxidatively robust molecules capable of achieving such a challenging task. A significant number of Ru coordination complexes have been identified as water oxidation catalysts (WOCs) and are among the best understood from a mechanistic perspective. In this review, we describe the catalytic performance of these complexes and focus our attention on the factors that influence their performance during catalysis, especially in cases where a detailed mechanistic investigation has been carried out. The collective information extracted from all the catalysts studied allows one to identify the key features that govern the complex chemistry associated with the catalytic water oxidation reaction. This includes the stability of trans -O-Ru-O groups, the change in coordination number from CN6 to CN7 at Ru high oxidation states, the ligand flexibility, the capacity to undergo intramolecular proton transfer, the bond strain, the axial ligand substitution, and supramolecular effects. Overall, combining all this information generates a coherent view of this complex chemistry.
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- 2023
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30. Heterogeneous Electrochemical Ammonia Oxidation with a Ru-bda Oligomer Anchored on Graphitic Electrodes via CH-π Interactions.
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Beiler AM, Denisiuk A, Holub J, Sánchez-Baygual FJ, Gil-Sepulcre M, Ertem MZ, Moonshiram D, Piccioni A, and Llobet A
- Abstract
Molecular catalysts can promote ammonia oxidation, providing mechanistic insights into the electrochemical N
2 cycle for a carbon-free fuel economy. We report the ammonia oxidation activity of carbon anodes functionalized with the oligomer {[RuII (bda-κ- N2 O2 )(4,4'-bpy)]10 (4,4'-bpy)}, Rubda-10 , where bda is [2,2'-bipyridine]-6,6'-dicarboxylate and 4,4'-bpy is 4,4'-bipyridine. Electrocatalytic studies in propylene carbonate demonstrate that the Ru-based hybrid anode used in a 3-electrode configuration transforms NH3 to N2 and H2 in a 1:3 ratio with near-unity faradaic efficiency at an applied potential of 0.1 V vs Fc+/0 , reaching turnover numbers of 7500. X-ray absorption spectroscopic analysis after bulk electrolysis confirms the molecular integrity of the catalyst. Based on computational studies together with electrochemical evidence, ammonia nucleophilic attack is proposed as the primary pathway that leads to critical N-N bond formation., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)- Published
- 2022
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31. Mixed Infection of Blackcurrant with a Novel Cytorhabdovirus and Black Currant-Associated Nucleorhabdovirus.
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Petrzik K, Přibylová J, Špak J, Sarkisova T, Fránová J, Holub J, Skalík J, and Koloniuk I
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- Genome, Viral, Open Reading Frames, Plant Diseases, Phylogeny, Plant Breeding, Ribes, Coinfection genetics, Rhabdoviridae genetics
- Abstract
A virome screen was performed on a new breeding line, KB1, of blackcurrant. Rhabdovirus-like particles were observed by electron microscopy in ultrathin sections of flower stalks, and the complete genome sequence of a novel virus, provisionally named blackcurrant rhabdovirus 2 (BCRV2), was determined and verified using high-throughput sequencing. The genomic organization of BCRV2 was characteristic of cytorhabdoviruses (family Rhabdoviridae ) and included seven genes: 3 ́- N-P´-P-P3-M-G-L -5 ́. BLASTP analysis revealed that the putative L protein had the highest amino acid sequence identity (75 %) with strawberry virus 2. BCRV2 was detected in Cryptomyzus galeopsidis , but efficient transmission by this aphid was not confirmed. Of note, we observed coinfection of the KB1 line with blackcurrant-associated rhabdovirus (BCaRV) by RT-PCR. This is likely the first evidence of the presence of a cyto- and a nucleorhabdovirus in a single host., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
- Published
- 2022
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32. Online teaching of practical classes under the Covid-19 restrictions.
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Svatos J, Holub J, Fischer J, and Sobotka J
- Abstract
COVID -19 pandemic and its restrictions bring new challenges to all aspects and phases of higher education. At universities, new remote formats have been developed and deployed for lectures and laboratory exercises. This article addresses challenges and introduces the new experience with lectures and laboratory classes during the pandemic time at the Department of Measurement of the Czech Technical University in Prague, Faculty of Electrical Engineering. Based on the student survey of more than 250 students describes the possibilities of how to adapt the lectures during the lockdown. The article also introduces the Home Lab, a tool developed in the department that helps in distance teaching practical electronic classes. Home Lab includes two parts with functional groups, a Laboratory Experimental Device and a System of Measurement Instruments. The article also shows the opportunity for suitable remote exercises and variants of circuits that can be easily assembled and measured using Software Defined Instrument based on various microcontrollers. A detailed description of all Software Defined Instruments is also present. During the Pandemic, the home lab model was successfully practically verified during distance learning in three subjects, with more than 150 students per semester. It has also been shown that the Home Lab can be successfully deployed for a semester project. The article also presents experience with the teaching software-oriented courses. At the end of the article, practical knowledge and an experience from distance teaching during a three-semester lockdown are shared., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 CTU in Prague.)
- Published
- 2022
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33. Secondary Prevention after Myocardial Infarction: What to Do and Where to Do It.
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Tuka V, Holub J, and Bělohlávek J
- Abstract
Acute myocardial infarction is a manifestation of atherosclerosis which may be fatal. In-hospital and short-term mortality rates after an acute myocardial infarction have declined in the past few decades. However, although long-term mortality has decreased, it remains unacceptably high. This review paper summarises the non-pharmacological interventions (smoking cessation, physical activity, nutrition, and psychosocial intervention) and pharmacological approaches (antiplatelet and lipid-lowering therapy, renin-angiotensin-aldosterone system inhibitors, beta-blockers, and glucose-lowering drugs) to secondary prevention after a myocardial infarction. The provision of secondary prevention services is established through cardiac rehabilitation, which consists of several discussed components. Finally, we discuss the quality indicators for long-term care after an acute myocardial infarction., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2022 The Author(s). Published by IMR Press.)
- Published
- 2022
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34. Reversed-phase chromatography as an effective tool for the chiral separation of anionic and zwitterionic carboranes using polysaccharide-based chiral selectors.
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Horáček O, Marvalová J, Štilcová K, Holub J, Grüner B, and Kučera R
- Subjects
- Anions, Chromatography, High Pressure Liquid methods, Cobalt, Stereoisomerism, Chromatography, Reverse-Phase, Polysaccharides chemistry
- Abstract
The aspect of the different spatial arrangement of anionic cobalt bis(dicarbollides) and dicarba-nido-undecaboranes remains grossly overlooked despite increased scientific interest. Regarding their growing potential, which does not limit only to medicinal chemistry, suitable enantioseparation methods are needed. The presented paper explores the possibilities of chiral separations of anionic cobalt bis(dicarbollide) and dicarba-7,8-nido-undecaborane derivatives on four polysaccharide-based columns under reversed-phase conditions. The chromatographic behavior of anionic derivatives was evaluated and compared with that of zwitterionic clusters. The isocratic procedure for HPLC method development was suggested. The main parameters for the optimization of separations were described. Successful chiral separations were critically compared to previously reported results in normal phase and polar-organic mode. Reversed-phase separations are superior in resolution, lower consumption of organic solvents, and flexibility during the method development. Moreover, the first chiral discrimination of some hydroxyalkyl derivatives of anionic cobalt bis(dicarbollides) is reported. The outcomes of this work may be used for method development in any area, where the chirality of these interesting molecules is of concern., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)
- Published
- 2022
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35. Adenoma Detection Rates in 45-49-Year-Old Persons Undergoing Screening Colonoscopy: Analysis From the GIQuIC Registry.
- Author
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Bilal M, Holub J, Greenwald D, Pochapin MB, Rex DK, and Shaukat A
- Subjects
- Aged, Colonoscopy, Early Detection of Cancer, Humans, Mass Screening, Middle Aged, Registries, Adenoma diagnosis, Colorectal Neoplasms diagnosis, Colorectal Neoplasms epidemiology
- Abstract
Introduction: The impact of lowering the colon cancer screening age from 50 to 45 years on the endoscopist adenoma detection rate (ADR) is not well studied., Methods: We used average-risk screening colonoscopies submitted to the GI Quality Improvement Consortium registry from 2014 to 2020 among individuals aged 45-75 years. We used the 1-way ANOVA test to determine differences between ADRs among 45-49-year-old, 50-54-year-old, and 50-75-year-old individuals., Results: A total of 2,806,539 screening colonoscopies were performed by 814 endoscopists. The mean ADR in the 45-49-year-old group was 28.6% compared with 31.8% for the 50-54-year-old group (P < 0.001) and 36.3% for the 50-75-year-old group (P < 0.001)., Discussion: Endoscopists might see a small drop in their ADR once a higher proportion of 45-49-year-old patients start undergoing screening colonoscopy., (Copyright © 2022 by The American College of Gastroenterology.)
- Published
- 2022
- Full Text
- View/download PDF
36. Online teaching at CTU in Prague aka university under COVID restrictions.
- Author
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Svatos J, Holub J, Fischer J, and Sobotka J
- Abstract
Covid-19 related restrictions bring new challenges to all aspects and phases of higher education. At universities, new remote formats are deployed or even developed both for lectures and laboratory exercises. This article addresses new challenges and describes the experience with lessons during the pandemic time at the Department of Measurement of the Czech Technical University in Prague, Faculty of Electrical Engineering. It introduces the best practices exercised using the Home Lab, which helps in distance teaching of practical electronic classes. Home Lab includes two models with functional groups, a Laboratory Experimental Device and System of Measurement Instruments. The article also shows the possibilities of suitable remote exercises and variants of circuits that can be easily assembled and measured using Software Defined Instrument based on STM microcontrollers. During the pandemic, the home lab model was successfully practically verified during distance learning in three classes, with more than 150 students. The article also presents experience with the teaching of software-oriented courses. At first glance, their transformation can be viewed as straightforward. However, practical realization reveals few remarkable details.
- Published
- 2021
- Full Text
- View/download PDF
37. Evaluation of digital watermarking on subjective speech quality.
- Author
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Kowalczuk Y and Holub J
- Subjects
- Algorithms, China, Humans, Language, Speech Perception, Telecommunications, Data Compression methods, Pattern Recognition, Automated methods
- Abstract
New methods of securing the distribution of audio content have been widely deployed in the last twenty years. Their impact on perceptive quality has, however, only been seldomly the subject of recent extensive research. We review digital speech watermarking state of the art and provide subjective testing of watermarked speech samples. Latest speech watermarking techniques are listed, with their specifics and potential for further development. Their current and possible applications are evaluated. Open-source software designed to embed watermarking patterns in audio files is used to produce a set of samples that satisfies the requirements of modern speech-quality subjective assessments. The patchwork algorithm that is coded in the application is mainly considered in this analysis. Different watermark robustness levels are used, which allow determining the threshold of detection to human listeners. The subjective listening tests are conducted following ITU-T P.800 Recommendation, which precisely defines the conditions and requirements for subjective testing. Further analysis tries to determine the effects of noise and various disturbances on watermarked speech's perceived quality. A threshold of intelligibility is estimated to allow further openings on speech compression techniques with watermarking. The impact of language or social background is evaluated through an additional experiment involving two groups of listeners. Results show significant robustness of the watermarking implementation, retaining both a reasonable net subjective audio quality and security attributes, despite mild levels of distortion and noise. Extended experiments with Chinese listeners open the door to formulate a hypothesis on perception variations with geographical and social backgrounds., (© 2021. The Author(s).)
- Published
- 2021
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38. Synthesis, Structure, and Ammonia Oxidation Catalytic Activity of Ru-NH 3 Complexes Containing Multidentate Polypyridyl Ligands.
- Author
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Holub J, Vereshchuk N, Sánchez-Baygual FJ, Gil-Sepulcre M, Benet-Buchholz J, and Llobet A
- Abstract
Ammonia (electro)oxidation with molecular catalysts is a rapidly developing topic with wide practical applications ahead. We report here the catalytic ammonia oxidation reaction (AOR) activity using [Ru(tda-κ-N
3 O)(py)2 ], 2 , (tda2- is 2,2':6',2''-terpyridine-6,6''-dicarboxylate; py is pyridine) as a catalyst precursor. Furthermore, we also describe the rich chemistry associated with the reaction of Ru-tda and Ru-tPa (tPa-4 is 2,2':6',2''-terpyridine-6,6''-diphosphonate) complexes with NH3 and N2 H4 using [RuII (tda-κ-N3 O)(dmso)Cl] (dmso is dimethyl sulfoxide) and [RuII (tPa-κ-N3 O)(py)2 ], 8 , as synthetic intermediates, respectively. All the new complexes obtained here were characterized spectroscopically by means of UV-vis and NMR. In addition, a crystal X-ray diffraction analysis was performed for complexes trans -[RuII (tda-κ-N3 )(py)2 (NH3 )], 4 , trans -[RuII (tda-κ-N3 )(N-NH2 )(py)2 ], 5 , cis -[RuII (tda-κ-N3 )(py)(NH3 )2 ], 6 (30%), and cis -[RuII (tda-k-N3 )(dmso)(NH3 )2 ], 7 (70%). The AOR activity associated with 2 and 8 as catalyst precursors was studied in organic and aqueous media. For 2 , turnover numbers of 7.5 were achieved under bulk electrolysis conditions at an Eapp = 1.4 V versus normal hydrogen electrode in acetonitrile. A catalytic cycle is proposed based on electrochemical and kinetic evidence.- Published
- 2021
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39. Inhibitors of CA IX Enzyme Based on Polyhedral Boron Compounds.
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Kugler M, Nekvinda J, Holub J, El Anwar S, Das V, Šícha V, Pospíšilová K, Fábry M, Král V, Brynda J, Kašička V, Hajdúch M, Řezáčová P, and Grüner B
- Subjects
- Binding Sites, Boron Compounds metabolism, Boron Compounds therapeutic use, Carbonic Anhydrase IX metabolism, Carbonic Anhydrase Inhibitors chemical synthesis, Carbonic Anhydrase Inhibitors metabolism, Carbonic Anhydrase Inhibitors therapeutic use, Humans, Molecular Dynamics Simulation, Neoplasms drug therapy, Organometallic Compounds chemistry, Structure-Activity Relationship, Sulfonamides chemistry, Boron Compounds chemistry, Carbonic Anhydrase IX antagonists & inhibitors, Carbonic Anhydrase Inhibitors chemistry
- Abstract
This review describes recent progress in the design and development of inhibitors of human carbonic anhydrase IX (CA IX) based on space-filling carborane and cobalt bis(dicarbollide) clusters. CA IX enzyme is known to play a crucial role in cancer cell proliferation and metastases. The new class of potent and selective CA IX inhibitors combines the structural motif of a bulky inorganic cluster with an alkylsulfamido or alkylsulfonamido anchor group for Zn
2+ ion in the enzyme active site. Detailed structure-activity relationship (SAR) studies of a large series containing 50 compounds uncovered structural features of the cluster-containing inhibitors that are important for efficient and selective inhibition of CA IX activity. Preclinical evaluation of selected compounds revealed low toxicity, favorable pharmacokinetics and ability to reduce tumor growth. Cluster-containing inhibitors of CA IX can thus be considered as promising candidates for drug development and/or for combination therapy in boron neutron capture therapy (BNCT)., (© 2021 Wiley-VCH GmbH.)- Published
- 2021
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40. Transformation of various multicenter bondings within bicapped-square antiprismatic motifs: Z -rearrangement.
- Author
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Bakardjiev M, Holub J, Růžičková Z, Růžička A, Fanfrlík J, Štíbr B, McKee ML, and Hnyk D
- Abstract
Reported herein are mutual rearrangements in the whole series of seven bicapped-square antiprismatic closo -C
2 B8 H10 by means of high-quality computations that disprove the earlier postulated dsd (diamond-square-diamond) scheme for these isomerizations. The experimentally existing closo -1,2-C2 B8 H10 was able to be converted to 1,6-, and 1,10-isomers by pyrolysis, and the dsd (diamond-square-diamond) mechanism was offered as an explanation of these processes. However, these computations disprove the postulated dsd scheme for these isomerizations that take place in the ten-vertex closo series. Experimentally observed thermal rearrangements, both in the parent and substituted closo -1,2-C2 B8 H10 , closo -1-CB9 H10 - , and closo -B10 H10 2- , indirectly support these refined computations. All these processes are based on the new concept of the so-called Z -mechanism, being consistent with a transition state of a boat shape with an open hexagonal belt that results from the initial breakage of three bonds. Such bond breakings and the consequent bond formations bring to mind the shape of the letter Z . In effect, the pattern of multicenter bonding shifts from reactant through a transition state to product. The molecular rearrangements that are available experimentally favour either the axial or equatorial isomers, and this ratio depends on temperature and the type of cluster and its substitution.- Published
- 2021
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41. Benchmarking Adenoma Detection Rates for Colonoscopy: Results From a US-Based Registry.
- Author
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Shaukat A, Holub J, Pike IM, Pochapin M, Greenwald D, Schmitt C, and Eisen G
- Subjects
- Aged, Aged, 80 and over, Benchmarking, Female, Humans, Male, Mass Screening, Middle Aged, Quality Improvement, Registries, United States, Adenoma diagnosis, Colonic Neoplasms diagnosis, Colonoscopy standards, Early Detection of Cancer standards
- Abstract
Introduction: Adenoma detection rate (ADR) is highly variable across practices, and national or population-based estimates are not available. Our aim was to study the ADR, variability of rates over time, and factors associated with detection rates of ADR in a national sample of patients undergoing colonoscopy., Methods: We used colonoscopies submitted to the GI Quality Improvement Consortium, Ltd. registry from 2014 to 2018 on adults aged 50-89 years. We used hierarchical logistic models to study factors associated with ADR., Results: A total of 2,646,833 colonoscopies were performed by 1,169 endoscopists during the study period. The average ADR for screening colonoscopies per endoscopist was 36.80% (SD 10.21), 44.08 (SD 10.98) in men and 31.20 (SD 9.65) in women. Adjusted to the US population, the ADR was 39.08%. There was a significant increase in ADR from screening colonoscopies over the study period from 33.93% in 2014 to 38.12% in 2018., Discussion: The average ADR from a large national US sample standardized to the US population is 39.05% and has increased over time., (Copyright © 2021 by The American College of Gastroenterology.)
- Published
- 2021
- Full Text
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42. Production of Enriched Sporidiobolus sp. Yeast Biomass Cultivated on Mixed Coffee Hydrolyzate and Fat/Oil Waste Materials.
- Author
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Szotkowski M, Holub J, Šimanský S, Hubačová K, Hladká D, Němcová A, and Marová I
- Abstract
One of the most addressed topics today is the transfer from a linear model of economics to a model of circular economics. It is a discipline that seeks to eliminate waste produced by various industries. The food industry generates huge amounts of waste worldwide, particularly the coffee industry, and related industries produce millions of tons of waste a year. These wastes have potential utility in biotechnology, and in the production of energy, fuels, fertilizers and nutrients, using green techniques such as anaerobic digestion, co-digestion, composting, enzymatic action, and ultrasonic and hydrothermal carbonization. This work is focused on the biotechnological use of processed spent coffee grounds (SCG) and waste fat/oil materials by some Sporidiobolus sp. carotenogenic yeasts in the model of circular economics. The results show that selected yeast strains are able to grow on SCG hydrolysate and are resistant to antimicrobial compounds present in media. The most productive strain Sporidiobolus pararoseus CCY19-9-6 was chosen for bioreactor cultivation in media with a mixture of coffee lignocellulose fraction and some fat wastes. Sporidiobolus pararoseus CCY19-9-6 was able to produce more than 22 g/L of biomass in mixture of SCG hydrolysate and both coffee oil and frying oil. The combined waste substrates induced the production of lipidic metabolites, whereby the production of carotenoids exceeded 5 mg/g of dry biomass. On media with coffee oil, this strain produced high amounts of ubiquinone (8.265 ± 1.648 mg/g) and ergosterol (13.485 ± 1.275 mg/g). Overall, the results prove that a combination of waste substrates is a promising option for the production of carotenoid- and lipid-enriched yeast biomass.
- Published
- 2021
- Full Text
- View/download PDF
43. Access to cationic polyhedral carboranes via dynamic cage surgery with N-heterocyclic carbenes.
- Author
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Vrána J, Holub J, Samsonov MA, Růžičková Z, Cvačka J, McKee ML, Fanfrlík J, Hnyk D, and Růžička A
- Abstract
Polyhedral boranes and heteroboranes appear almost exclusively as neutral or anionic species, while the cationic ones are protonated at exoskeletal heteroatoms or they are instable. Here we report the reactivity of 10-vertex closo-dicarbadecaboranes with one or two equivalents of N-heterocyclic carbene to 10-vertex nido mono- and/or bis-carbene adducts, respectively. These complexes easily undergo a reaction with HCl to give cages of stable and water soluble 10-vertex nido-type cations with protonation in the form of a BHB bridge or 10-vertex closo-type cations containing one carbene ligand when originating from closo-1,10-dicarbadecaborane. The reaction of a 10-vertex nido mono-carbene adduct with phosphorus trichloride gives nido-11-vertex 2-phospha-7,8-dicarbaundecaborane, which undergoes an oxidation of the phosphorus atom to P = O, while the product of a bis-carbene adduct reaction is best described as a distorted C
2 B6 H8 fragment bridged by the (BH)2 PCl2 + moiety., (© 2021. The Author(s).)- Published
- 2021
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44. Thiaborane Icosahedral Barrier Increased by the Functionalization of all Terminal Hydrogens in closo -1-SB 11 H 11 .
- Author
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Bakardjiev M, Holub J, Bavol D, Vrána J, Samsonov MA, Růžička A, Růžičková Z, Fanfrlík J, and Hnyk D
- Abstract
The electrophilic substitution of icosahedral closo- 1-SB
11 H11 with methyl iodide has resulted in two B-functionalized thiaboranes, 7,12-I2 -2,3,4,5,6,8,9,10,11-(CH3 )9 -1- closo -SB11 and 7,8,12-I3 -2,3,4,5,6,9,10,11-(CH3 )8 - closo -1-SB11 , with the former being significantly predominant. These two icosahedral thiaboranes are the first cases of polysubstituted polyhedral boron clusters with another vertex that differs from B and C. Such polyfunctionalizations have increased the earlier observed thiaborane icosahedral barrier, not exhibiting any reactivity toward bases, unlike the parent thiaborane. The search for methylation pathways has revealed that the complete B11 -methylation is impossible, like in the case of decaborane(14), where this seems to be a result of the positively charged upper parts of these two molecules.- Published
- 2021
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45. Bioreactor Co-Cultivation of High Lipid and Carotenoid Producing Yeast Rhodotorula kratochvilovae and Several Microalgae under Stress.
- Author
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Szotkowski M, Holub J, Šimanský S, Hubačová K, Sikorová P, Mariničová V, Němcová A, and Márová I
- Abstract
The co-cultivation of red yeasts and microalgae works with the idea of the natural transport of gases. The microalgae produce oxygen, which stimulates yeast growth, while CO
2 produced by yeast is beneficial for algae growth. Both microorganisms can then produce lipids. The present pilot study aimed to evaluate the ability of selected microalgae and carotenogenic yeast strains to grow and metabolize in co-culture. The effect of media composition on growth and metabolic activity of red yeast strains was assessed simultaneously with microalgae mixotrophy. Cultivation was transferred from small-scale co-cultivation in Erlenmeyer flasks to aerated bottles with different inoculation ratios and, finally, to a 3L bioreactor. Among red yeasts, the strain R. kratochvilovae CCY 20-2-26 was selected because of the highest biomass production on BBM medium. Glycerol is a more suitable carbon source in the BBM medium and urea was proposed as a compromise. From the tested microalgae, Desmodesmus sp. were found as the most suitable for co-cultivations with R. kratochvilovae. In all co-cultures, linear biomass growth was found (144 h), and the yield was in the range of 8.78-11.12 g/L of dry biomass. Lipids increased to a final value of 29.62-31.61%. The FA profile was quite stable with the UFA portion at about 80%. Around 1.98-2.49 mg/g CDW of carotenoids with torularhodine as the major pigment were produced, ubiquinone production reached 5.41-6.09 mg/g, and ergosterol yield was 6.69 mg/g. Chlorophyll production was very low at 2.11 mg/g. Pilot experiments have confirmed that carotenogenic yeasts and microalgae are capable of symbiotic co-existence with a positive impact om biomass growth and lipid metabolites yields.- Published
- 2021
- Full Text
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46. Determination of acidity constants, ionic mobilities, and hydrodynamic radii of carborane-based inhibitors of carbonic anhydrases by capillary electrophoresis.
- Author
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Šolínová V, Brynda J, Šícha V, Holub J, Grűner B, and Kašička V
- Subjects
- Acids, Electrophoresis, Capillary, Hydrogen-Ion Concentration, Ions, Carbonic Anhydrases, Hydrodynamics
- Abstract
Capillary electrophoresis (CE) has been applied for determination of the thermodynamic acidity constants (pK
a ) of the sulfamidoalkyl and sulfonamidoalkyl groups, the actual and limiting ionic mobilities and hydrodynamic radii of important compounds, eight carborane-based inhibitors of carbonic anhydrases, which are potential new anticancer drugs. Two types of carboranes were investigated, (i) icosahedral cobalt bis(dicarbollide)(1-) ion with sulfamidoalkyl moieties, and (ii) 7,8-nido-dicarbaundecaborate with sulfonamidoalkyl side chains. First, the mixed acidity constants, pKa mix , of the sulfamidoalkyl and sulfonamidoalkyl groups of the above carboranes and their actual ionic mobilities were determined by nonlinear regression analysis of the pH dependences of their effective electrophoretic mobility measured by capillary electrophoresis in the pH range 8.00-12.25, at constant ionic strength (25 mM), and constant temperature (25°C). Second, the pKa mix were recalculated to the thermodynamic pKa s using the Debye-Hückel theory. The sulfamidoalkyl and sulfonamidoalkyl groups were found to be very weakly acidic with the pKa s in the range 10.78-11.45 depending on the type of carborane cluster and on the position and length of the alkyl chain on the carborane scaffold. These pKa s were in a good agreement with the pKa s (10.67-11.27) obtained by new program AnglerFish (freeware at https://echmet.natur.cuni.cz), which provides thermodynamic pKa s and limiting ionic mobilities directly from the raw CE data. The absolute values of the limiting ionic mobilities of univalent and divalent carborane anions were in the range 18.3-27.8 TU (Tiselius unit, 1 × 10-9 m2 /Vs), and 36.4-45.9 TU, respectively. The Stokes hydrodynamic radii of univalent and divalent carborane anions varied in the range 0.34-0.52 and 0.42-0.52 nm, respectively., (© 2021 Wiley-VCH GmbH.)- Published
- 2021
- Full Text
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47. Increasing Prevalence of Polyps > 9 mm in Young Adults Aged 40 to 59 Years Undergoing Colonoscopy From 2002 to 2014.
- Author
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Yip B, Holub J, and Lieberman D
- Subjects
- Adult, Age Distribution, Colonic Polyps pathology, Colorectal Neoplasms pathology, Databases, Factual, Female, Humans, Male, Middle Aged, Predictive Value of Tests, Prevalence, Time Factors, Tumor Burden, Colonic Polyps epidemiology, Colonoscopy, Colorectal Neoplasms epidemiology
- Published
- 2021
- Full Text
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48. Cobalt Bis(dicarbollide) Alkylsulfonamides: Potent and Highly Selective Inhibitors of Tumor Specific Carbonic Anhydrase IX.
- Author
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Grüner B, Kugler M, El Anwar S, Holub J, Nekvinda J, Bavol D, Růžičková Z, Pospíšilová K, Fábry M, Král V, Brynda J, and Řezáčová P
- Subjects
- Carbonic Anhydrase IX, Cobalt, Humans, Carbonic Anhydrase Inhibitors, Neoplasms
- Abstract
Invited for this month's cover is a collaboration from three institutes from the Czech Academy of Sciences: Institute of Inorganic Chemistry, Institute of Organic Chemistry and Biochemistry, and Institute of Molecular Genetics, and the University of Pardubice. The cover picture shows a family of potent and selective CA IX inhibitors that combines the structural motif of a bulky inorganic cobalt bis(dicarbollide) polyhedral ion with a propylsulfonamido anchor group. Read the full text of the article at 10.1002/cplu.202000574., (© 2021 Wiley-VCH GmbH.)
- Published
- 2021
- Full Text
- View/download PDF
49. PFP Compressed Suffix Trees.
- Author
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Boucher C, Cvacho O, Gagie T, Holub J, Manzini G, Navarro G, and Rossi M
- Abstract
Prefix-free parsing (PFP) was introduced by Boucher et al. (2019) as a preprocessing step to ease the computation of Burrows-Wheeler Transforms (BWTs) of genomic databases. Given a string S , it produces a dictionary D and a parse P of overlapping phrases such that BWT( S ) can be computed from D and P in time and workspace bounded in terms of their combined size |PFP( S )|. In practice D and P are significantly smaller than S and computing BWT( S ) from them is more efficient than computing it from S directly, at least when S is the concatenation of many genomes. In this paper, we consider PFP( S ) as a data structure and show how it can be augmented to support full suffix tree functionality, still built and fitting within O (|PFP( S )|) space. This entails the efficient computation of various primitives to simulate the suffix tree: computing a longest common extension (LCE) of two positions in S ; reading any cell of its suffix array (SA), of its inverse (ISA), of its BWT, and of its longest common prefix array (LCP); and computing minima over ranges and next/previous smaller value queries over the LCP. Our experimental results show that the PFP suffix tree can be efficiently constructed for very large repetitive datasets and that its operations perform competitively with other compressed suffix trees that can only handle much smaller datasets.
- Published
- 2021
- Full Text
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50. Variation Over Time and Factors Associated With Detection Rates of Sessile Serrated Lesion Across the United States: Results Form a National Sample Using the GIQuIC Registry.
- Author
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Shaukat A, Holub J, Greenwald D, Eisen G, and Schmitt C
- Subjects
- Adenomatous Polyps epidemiology, Adenomatous Polyps pathology, Adolescent, Adult, Aged, Aged, 80 and over, Colonic Polyps epidemiology, Colonic Polyps pathology, Colorectal Neoplasms epidemiology, Colorectal Neoplasms pathology, Early Detection of Cancer, Female, Gastroenterologists, Humans, Male, Middle Aged, Pathology, Clinical, Quality Improvement, Registries, Sex Factors, Specialization, Time Factors, United States epidemiology, Watchful Waiting, Young Adult, Adenomatous Polyps diagnosis, Colonic Polyps diagnosis, Colonoscopy, Colorectal Neoplasms diagnosis
- Abstract
Introduction: Sessile serrated lesions (SSLs) are important precursor lesions for the CpG island-methylated pathway to colorectal cancer. The reported detection rates of SSL are highly variable, and national or population-based estimates are not available. Patient-, provider-, and procedure-level factors associated with the detection rates of SSL have not been well described. The aim of our study was to study the detection rates of SSL, variability of rates over time, and factors associated with detection rates of SSL in a national sample of patients undergoing colonoscopy using the GIQuIC registry., Methods: We used colonoscopies submitted to the GIQuIC registry from 2014 to 2017 on adults, aged 18-89 years. Only the first colonoscopy record per patient was included. Indications for colonoscopy were categorized as screening, diagnostic, and surveillance. We used the hierarchical logistic models to study the factors associated with the detection rates of SSL. The Cochrane-Armitage test was used to study the significance of trend over time., Results: There were a total of 5,173,211 colonoscopies performed by 3,934 endoscopists during the study period. Among the 2,101,082 screening colonoscopies over the study period in adults older than or equal to 50 years that were complete to the cecum, the average detection rate per endoscopist for SSL was 6.43% (SD 5.18) and 6.25% standardized for the 2010 US population. There was a significant increase in the detection rates of SSLs from screening colonoscopies over the study period from 4.99% in 2014 to 7.09% in 2017 (P trend <0.001). Clinically significant factors associated with higher detection rates of SSL were longer withdrawal times (>11 minutes vs ≤6 minutes) (odds ratio [OR] 9.61; 9.03-10.24), adequate preparation (OR 1.25; 1.22-1.28), female sex (OR 1.17; 1.16-1.18), and use of a specialized gastrointestinal pathology group (OR 1.12; 95% confidence interval 1.04, 1.19)., Discussion: Population-based estimates of the detection rates of SSL are 6% and have increased over time., (Copyright © 2020 by The American College of Gastroenterology.)
- Published
- 2021
- Full Text
- View/download PDF
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