Search results for "sort"
showing 10 items of 487 documents
Asymmetric Disulfanylbenzamides as Irreversible and Selective Inhibitors of Staphylococcus aureus Sortase A
2020
Abstract Staphylococcus aureus is one of the most frequent causes of nosocomial and community‐acquired infections, with drug‐resistant strains being responsible for tens of thousands of deaths per year. S. aureus sortase A inhibitors are designed to interfere with virulence determinants. We have identified disulfanylbenzamides as a new class of potent inhibitors against sortase A that act by covalent modification of the active‐site cysteine. A broad series of derivatives were synthesized to derive structure‐activity relationships (SAR). In vitro and in silico methods allowed the experimentally observed binding affinities and selectivities to be rationalized. The most active compounds were f…
A model-based approach to Spotify data analysis: a Beta GLMM
2020
Digital music distribution is increasingly powered by automated mechanisms that continuously capture, sort and analyze large amounts of Web-based data. This paper deals with the management of songs audio features from a statistical point of view. In particular, it explores the data catching mechanisms enabled by Spotify Web API and suggests statistical tools for the analysis of these data. Special attention is devoted to songs popularity and a Beta model, including random effects, is proposed in order to give the first answer to questions like: which are the determinants of popularity? The identification of a model able to describe this relationship, the determination within the set of char…
Assessing the quality of studies in meta-research: Review/guidelines on the most important quality assessment tools
2020
Systematic reviews and meta-analyses pool data from individual studies to generate a higher level of evidence to be evaluated by guidelines. These reviews ultimately guide clinicians and stakeholders in health-related decisions. However, the informativeness and quality of evidence synthesis inherently depend on the quality of what has been pooled into meta-research projects. Moreover, beyond the quality of included individual studies, only a methodologically correct process, in relation to systematic reviews and meta-analyses themselves, can produce a reliable and valid evidence synthesis. Hence, quality of meta-research projects also affects evidence synthesis reliability. In this overview…
Prokaryotic symbiotic consortia and the origin of nucleated cells: A critical review of Lynn Margulis hypothesis.
2021
The publication in the late 1960s of Lynn Margulis endosymbiotic proposal is a scientific milestone that brought to the fore of evolutionary discussions the issue of the origin of nucleated cells. Although it is true that the times were ripe, the timely publication of Lynn Margulis' original paper was the product of an intellectually bold 29-years old scientist, who based on the critical analysis of the available scientific information produced an all-encompassing, sophisticated narrative scheme on the origin of eukaryotic cells as a result of the evolution of prokaryotic consortia and, in bold intellectual stroke, put it all in the context of planetary evolution. A critical historical reas…
Tests for Differentiation in Gene Expression Using a Data-Driven Order or Weights for Hypotheses
2005
In the analysis of gene expression by microarrays there are usually few subjects, but high-dimensional data. By means of techniques, such as the theory of spherical tests or with suitable permutation tests, it is possible to sort the endpoints or to give weights to them according to specific criteria determined by the data while controlling the multiple type I error rate. The procedures developed so far are based on a sequential analysis of weighted p-values (corresponding to the endpoints), including the most extreme situation of weighting leading to a complete order of p-values. When the data for the endpoints have approximately equal variances, these procedures show good power properties…
Self-assembly of metallosupramolecular rhombi from chiral concave 9,9'-spirobifluorene-derived bis(pyridine) ligands.
2014
Two new 9,9’-spirobifluorene-based bis(4-pyridines) were synthesised in enantiopure and one also in racemic form. These ligands act as concave templates and form metallosupramolecular [(dppp)2M2L2] rhombi with cis-protected [(dppp)Pd]2+ and [(dppp)Pt]2+ ions. The self-assembly process of the racemic ligand preferably occurs in a narcissistic self-recognising manner. Hence, a mixture of all three possible stereoisomers [(dppp)2M2{(R)-L}2](OTf)4, [(dppp)2M2{(S)-L}2](OTf)4, and [(dppp)2M2{(R)-L}{(S)-L}](OTf)4 was obtained in an approximate 1.5:1.5:1 ratio which corresponds to an amplification of the homochiral assemblies by a factor of approximately three as evidenced by NMR spectroscopy and m…
Streptococcus Mutans sortāzes A ekspresija, attīrīšana un raksturošana zāļu vielu skrīningam
2019
Slimības, ko izraisa patogēni, īpaši multirezistenti, piemēram, Streptococcus mutans, ir nepieciešams apkarot. Multirezistentu grampozitīvu patogēnu baktēriju transpeptidāzes - sortāzes A - mērķproteīna inhibēšana mazina patogēnu saistīšanās spēju - virulenci - un līdz ar to arī rezistenci. Bakalaura darbā Streptococcus mutans sortāze A tiek izmantota kā instruments, lai pārbaudītu novatoriskus ķīmiskus savienojumus, kam piemīt spēja inhibēt sortāzi A. Mērķis bija, izmantojot zāļu vielu skrīninga metodi, atlasīt ķīmiskas vielas, kam piemīt sortāzes A inhibēšana un kuras varētu izmantot, lai apkarotu multirezistentu grampozitīvu patogēnu izraistītas slimības. Streptococcus mutans sortāzes A …
Solvent-free ball-milling subcomponent synthesis of metallosupramolecular complexes.
2015
Subcomponent self-assembly from components A, B, C, D, and Fe(2+) under solvent-free conditions by self-sorting leads to the construction of three structurally different metallosupramolecular iron(II) complexes. Under carefully selected ball-milling conditions, tetranuclear [Fe4 (AD2 )6 ](4-) 22-component cage 1, dinuclear [Fe2 (BD2 )3 ](2-) 11-component helicate 2, and 5-component mononuclear [Fe(CD3 )](2+) complex 3 were prepared simultaneously in a one-pot reaction from 38 components. Through subcomponent substitution reaction by adding subcomponent B, the [Fe4 (AD2 )6 ](4-) cage converts quantitatively to the [Fe2 (BD2 )3 ](2-) helicate, which, in turn, upon addition of subcomponent C, …
Dificultades para Codificar, Relacionar y Categorizar Problemas Verbales Algebraicos: dos estudios con estudiantes de secundaria y profesores en form…
2014
En resolución de problemas verbales por transferencia, la activación de problemas ya conocidos que sirvan de guía, depende de las analogías percibidas entre éstos y el problema a resolver. Se desarrollan dos estudios relacionados para analizar en qué características se basan los estudiantes para codificar problemas y detectar sus analogías, en tareas de categorización (sorting). Se utilizaron técnicas cuantitativas y cualitativas combinadas. Primero se analizó cómo los estudiantes de secundaria son influidos por diferentes variables características de problemas de ciencias. Una gran proporción de sujetos no fue capaz de percibir las analogías y diferencias adecuadas entre problemas. El segu…
Protein Kinase C-dependent Ubiquitination and Clathrin-mediated Endocytosis of the Cationic Amino Acid Transporter CAT-1*
2011
Cationic amino acid transporter 1 (CAT-1) is responsible for the bulk of the uptake of cationic amino acids in most mammalian cells. Activation of protein kinase C (PKC) leads to down-regulation of the cell surface CAT-1. To examine the mechanisms of PKC-induced down-regulation of CAT-1, a functional mutant of CAT-1 (CAT-1-HA-GFP) was generated in which a hemagglutinin antigen (HA) epitope tag was introduced into the second extracellular loop and GFP was attached to the carboxyl terminus. CAT-1-HA-GFP was stably expressed in porcine aorthic endothelial and human epithelial kidney (HEK) 293 cells. Using the HA antibody internalization assay we have demonstrated that PKC-dependent endocytosis…