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Cinètica, Enzim, and Velocitat de reacció

Allure, Gait, Marcha, Ballast, Balasto, Cinétique, Kinetics, Cinética, Ergonomie, Ergonomics, Ergonomía, Homme, Human, Hombre, Marche à pied, Walking, Caminata, Voie ferrée, Railway track, Vía férrea, Terrain irrégulier, ballast, gait analysis, irregular terrain, kinetics, railroad, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Psychologie. Psychophysiologie, Psychology. Psychophysiology, Niveaux d'activité. Psychomotricité, Activity levels. Psychomotricity, Activités psychomotrices, Psychomotor activities, Psychologie du travail, Occupational psychology, Ergonomie. Facteur humain, Ergonomics. Human factors, Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Education, Éducation, Applied physiology, ergonomics sports medicine, Physiologie appliquée, ergonomie, sport, Psychology, psychopathology, psychiatry, and Psychologie, psychopathologie, psychiatrie

Railroad workers often perform daily work activities on irregular surfaces, specifically on ballast rock. Previous research and injury epidemiology have suggested a relationship between working on irregular surfaces and postural instability. The purpose of this study was to examine the impact of walking on ballast for an extended duration on standing balance. A total of 16 healthy adult males walked on a 7.62 m × 4.57 m (25 ft × 15 ft) walking surface of no ballast (NB) or covered with ballast (B) of an average rock size of about 1 inch for 4h. Balance was evaluated using dynamic posturography with the NeuroCom® Equitest System ™ prior to experiencing the NB or B surface and again every 30 min during the 4 h of ballast exposure. Dependent variables were the sway velocity and root-mean-square (RMS) sway components in the medial-lateral and anterior-posterior directions. Repeated measures ANOVA revealed statistically significant differences in RMS and sway velocity between ballast surface conditions and across exposure times. Overall, the ballast surface condition induced greater sway in all of the dynamic posturography conditions. Walking on irregular surfaces for extended durations has a deleterious effect on balance compared to walking on a surface without ballast. These findings of changes in balance during ballast exposure suggest that working on an irregular surface may impact postural control. Practitioner Summary: Epidemiology and scientific literature indicate a conceivable connection between walking surface characteristics and injury. These potential links are particularly evident in the railroad industry given the ballast surfaces widely encountered. The current findings provide data in which to enhance current work practices focusing on postural instability.

Activité biologique, Biological activity, Actividad biológica, Agrégation moléculaire, Molecular aggregation, Agregación molecular, Antialzheimer, Antialzheimer agent, Cinétique, Kinetics, Cinética, Cytotoxicité, Cytotoxicity, Citotoxicidad, Décapeptide, Decapeptide, Decapéptido, Etude expérimentale, Experimental study, Estudio experimental, In vitro, Interaction intermoléculaire, Intermolecular interaction, Interacción intermolecular, Mécanisme action, Mechanism of action, Mecanismo acción, Propriété biologique, Biological properties, Propiedad biológica, Protéine amyloïde β, β Amyloid protein, Proteína amiloide β, Résonance plasmon surface, Surface plasmon resonance, Solution aqueuse, Aqueous solution, Solución acuosa, Morphologie agrégat, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères d'origine naturelle, Natural polymers, Protéines, Proteins, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, Polymers, paint and wood industries, and Polymères, industries des peintures et bois

This paper reports an active decapeptide inhibitor (RR: RYYAAFFARR) of β-amyloid (Aβ1―40) aggregation. Traditional inhibitors target the hydrophobic core of Aβ (Aβ16―20 were designed based on the single hydrophobic interaction. RR was designed to target an extended region (Aβ11―23), which contains three important regions of Aβ1―40. RR exhibits stronger binding affinity for Aβ1―40 (KD = 1.10 μM) than the known β-sheet breaker LPFFD (KD = 156 μM). Our study shows that RR inhibited the fibrillation of Aβ1―40 by nearly 75% at an equimolar concentration, and that a 1:4 ratio of Aβ1―40/ RR almost completely inhibited fibrillation. The interaction mechanism was also investigated by changing the ionic strength or the structure of RR. The results revealed that RR binds to Aβ1―40 because of its strong affinity for Aβ11―23, which is mainly driven by hydrophobic and electrostatic interactions and hydrogen bonding.

Mammalia, Rodentia, Système nerveux central, Central nervous system, Sistema nervioso central, Vertebrata, Analyse temporelle, Time analysis, Análisis temporal, Animal, Cinétique, Kinetics, Cinética, Comparaison interindividuelle, Interindividual comparison, Comparación interindividual, Encéphale, Encephalon, Encéfalo, Facteur BDNF, Brain derived neurotrophic factor, Factor BDNF, Neurotransmetteur, Neurotransmitter, Neurotransmisor, Rat, Rata, Stress, Estrés, Test nage forcée, BDNF expression, Brain, Individual differences, Neurotransmitters, Time course, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Psychologie. Psychophysiologie, Psychology. Psychophysiology, Psychophysiologie du comportement, Behavioral psychophysiology, Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Cognition, Physiology, morphology, Physiologie, morphologie, Psychophysiology, and Psychophysiologie

Individual differences in the forced swimming test (FST) could be associated with differential temporal dynamics of gene expression and neurotransmitter activity. We tested juvenile male rats in the FST and classified the animals into those with low and high immobility according to the amount of immobility time recorded in FST. These groups and a control group which did not undergo the FST were sacrificed either 1, 6 or 24 h after the test. We analyzed the expression of the CRF, CRFR1, BDNF and TrkB in the prefrontal cortex, hippocampus and nucleus accumbens as well as norepinephrine, dopamine, serotonin, glutamate, GABA and glutamine in the hippocampus and nucleus accumbens. Animals with low immobility showed significant reductions of BDNF expression across time points in both the prefrontal cortex and the nucleus accumbens when compared with non-swim control. Moreover, rats with high immobility only showed a significant decrease of BDNF expression in the prefrontal cortex 6 h after the FST. Regarding neurotransmitters, only accumbal dopamine turnover and hippocampal glutamate content showed an effect of individual differences (i.e. animals with low and high immobility), whereas nearly all parameters showed significant differences across time points. Correlational analyses suggest that immobility in the FST, probably reflecting despair, is related to prefrontal cortical BDNF and to the kinetics observed in several other neurochemical parameters. Taken together, our results suggest that individual differences observed in depression-like behavior can be associated not only with changes in the concentrations of key neurochemical factors but also with differential time courses of such factors.

Cognition, Cognición, Motricité, Motricity, Motricidad, Perception, Percepción, Capacité mémoire, Memory capacity, Capacidad memoria, Cinétique, Kinetics, Cinética, Détection changement, Change detection, Detección cambio, Etude expérimentale, Experimental study, Estudio experimental, Homme, Human, Hombre, Mouvement corporel, Body movement, Movimiento corporal, Mouvement stimulus, Stimulus movement, Movimiento estímulo, Mémoire de travail, Working memory, Memoria trabajo, Vision, Visión, Mouvement biologique, Biological motion, Movimiento biológico, biological motion, capacity, kinetic working memory, working memory, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Psychologie. Psychophysiologie, Psychology. Psychophysiology, Niveaux d'activité. Psychomotricité, Activity levels. Psychomotricity, Activités psychomotrices, Psychomotor activities, Processus d'acquisition. Mémoire, Learning. Memory, Mémoire, Memory, Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychology, psychopathology, psychiatry, and Psychologie, psychopathologie, psychiatrie

Working memory (WM) mechanisms for verbal, spatial, and object information have been extensively examined, yet those for kinetic information are less known. The current study explored the WM capacity and architecture of kinetic information by examining the maintenance of biological motion (BM) stimuli in WM. Human BM is the most salient and biologically significant kinetic information encountered in everyday life. We isolated motion signals of human BM from non-BM sources by using point-light displays as to-be-memorized BM. During a change detection task, we found that, at most, 3 to 4 BM stimuli could be retained in WM (Experiment 1). Next, we found that extra colors, spatial locations, or shapes remembered concurrently with BM stimuli (Experiments 2, 3, and 4, respectively), did not affect BM memory considerably. However, BM memory was affected by a concurrent memory task of non-BM movements (Experiment 5). These results support the hypothesis that an independent storage buffer of WM exists for kinetic information, which can hold up to 3 to 4 motion units.

Approche probabiliste, Probabilistic approach, Enfoque probabilista, Cinétique, Kinetics, Cinética, Condition stationnaire, Stationary condition, Condición estacionaria, Discontinuité, Discontinuity, Discontinuidad, Erreur systématique, Bias, Error sistemático, Flux optique, Optical flow, Flujo óptico, Modélisation, Modeling, Modelización, Occlusion, Oclusión, Occultation, Ocultación, Profondeur champ, Depth of field, Profundidad campo, Relation ordre, Ordering, Relación orden, Réseau neuronal, Neural network, Red neuronal, Segmentation, Segmentación, Ségrégation, Segregation, Segregación, Texturation, Texturación, Texture, Textura, Vision ordinateur, Computer vision, Visión ordenador, Accretion and deletion, Figure-ground, Neural model, Visual cortex, Visual motion, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Informatique, automatique theorique, systemes, Computer science, control theory, systems, Intelligence artificielle, Artificial intelligence, Reconnaissance des formes. Traitement numérique des images. Géométrie algorithmique, Pattern recognition. Digital image processing. Computational geometry, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Vertebres: systeme nerveux et organes des sens, Vertebrates: nervous system and sense organs, Oeil et annexes. Voies et centres visuels. Vision, Eye and associated structures. Visual pathways and centers. Vision, Psychologie. Psychophysiologie, Psychology. Psychophysiology, Psychophysiologie du comportement, Behavioral psychophysiology, Corrélats anatomiques du comportement, Anatomical correlates of behavior, Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Cognition, Electronics, Electronique, Neurology, and Neurologie

Freezing is an effective defense strategy for some prey, because their predators rely on visual motion to distinguish objects from their surroundings. An object moving over a background progressively covers (deletes) and uncovers (accretes) background texture while simultaneously producing discontinuities in the optic flow field. These events unambiguously specify kinetic occlusion and can produce a crisp edge, depth perception, and figure-ground segmentation between identically textured surfaces - percepts which all disappear without motion. Given two abutting regions of uniform random texture with different motion velocities, one region appears to be situated farther away and behind the other (i.e., the ground) if its texture is accreted or deleted at the boundary between the regions, irrespective of region and boundary velocities. Consequently, a region with moving texture appears farther away than a stationary region if the boundary is stationary, but it appears closer (i.e., the figure) if the boundary is moving coherently with the moving texture. A computational model of visual areas V1 and V2 shows how interactions between orientation- and direction-selective cells first create a motion-defined boundary and then signal kinetic occlusion at that boundary. Activation of model occlusion detectors tuned to a particular velocity results in the model assigning the adjacent surface with a matching velocity to the far depth. A weak speed-depth bias brings faster-moving texture regions forward in depth in the absence of occlusion (shearing motion). These processes together reproduce human psychophysical reports of depth ordering for key cases of kinetic occlusion displays.

Protéine, Protein, Proteína, Activité biologique, Biological activity, Actividad biológica, Antialzheimer, Antialzheimer agent, Cinétique, Kinetics, Cinética, Clairance, Clearance, Depuración, Copulation chimique, Chemical coupling, Copulación química, Démence d'Alzheimer, Alzheimer disease, Demencia Alzheimer, Ethylène oxyde polymère, Ethylene oxide polymer, Etileno óxido polímero, Etude expérimentale, Experimental study, Estudio experimental, Inflammation, Inflamación, Internalisation, Internalization, Internalización, Microglie, Microglia, Microsphère, Microsphere, Microsfera, Mécanisme, Mechanism, Mecanismo, Particule sous micronique, Submicron particle, Partícula submicrónica, Phagocytose, Phagocytosis, Fagocitosis, Polymère greffé, Graft polymers, Protéine amyloïde β, β Amyloid protein, Proteína amiloide β, Préparation, Preparation, Preparación, Réaction surface, Surface reaction, Reacción superficie, Sérumalbumine, Serum albumin, Seroalbúmina, Lignée BV2, Particule fonctionnalisée, Peptide KLVFFC, Peptide amyloïde β, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Propriétés et caractérisation, Properties and characterization, Propriétés spéciales (catalyseur, réactif ou support), Special properties (catalyst, reagent or carrier), Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, Polymers, paint and wood industries, and Polymères, industries des peintures et bois

Imbalanced homeostasis and oligomerization of the amyloid-β (Aβ) peptide in the brain are hallmarks of Alzheimer's disease (AD). Microglia and macrophages play a critical role in the etiology of AD either by clearing Aβ from the brain or inducing inflammation. Recent evidence suggests that clearance of Aβ by microglia/macrophages via the phagocytic pathway is defective in AD, which can contribute to the accumulation of Aβ in the brain. We have recently demonstrated that protein microspheres modified at their surface with multiple copies of an Aβ-recognition motif can strongly bind Aβ, inhibit its aggregation, and directly reduce its toxicity by sequestering it from the medium. Here, we describe how microsphere-bound Aβ can stimulate microglial cells and be phagocytosed through a mechanism that is distinct from that of Aβ removal and, thus, contribute to the clearance of Aβ, even by defective microglial cells. The phagocytosis was most effective, with microspheres having a diameter of < 1 μm. The introduction of polyethylene glycol to the surface of the microspheres changed the kinetics of the phagocytosis. Moreover, while aggregated Aβ induced a significant inflammatory response that was manifested by the release of TNF-α, the microsphere-bound Aβ dramatically reduced the amount of.cytokine released from microglial cells.

Alcaloïde, Alkaloid, Alcaloide, Dérivé de la xanthine, Xanthine derivatives, Xantina derivado, Inhibiteur de la phosphodiesterase, Phosphodiesterase inhibitor, Inhibidor phosphodiesterase, Inhibiteur de la phosphodiestérase 4, Phosphodiesterase 4 inhibitor, Inhibidor fosfodiesterasa 4, Aliment, Food, Alimento, Analeptique respiratoire, Respiratory analeptic, Analéptico respiratorio, Antiasthmatique, Antiasthma agent, Agente antiasma, Bronchodilatateur, Bronchodilator, Broncodilatador, Caféine, Caffeine, Cafeína, Cardiotonique, Cardiotonic agent, Cardiotónico, Cinétique, Kinetics, Cinética, Diurétique, Diuretic, Diurético, Mesure simultanée, Simultaneous measurement, Medición simultánea, Psychotrope, Psychotropic, Psicotropo, Spectrophotométrie, Spectrophotometry, Espectrofotometría, Stimulant SNC, CNS stimulant, Estimulante SNC, Théobromine, Theobromine, Théophylline, Theophylline, Teofilina, Cerium sulphate, Kinetic reaction, Methylxanthines in food, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Food science technology, and Sciences technologies alimentaires

A novel kinetic spectrophotometric method was developed for the simultaneous determination of caffeine, theobromine and theophylline in food samples. This method was based on the different kinetic characteristics between the reactions of analytes with cerium sulphate in sulphuric acid and the associated change in absorbance at 320 nm. Experimental conditions, the effects of sulphuric acid, cerium sulphate and temperature, were optimised. Linear ranges (0.4―8.4 μg mL―1) for all three analytes were established, and the limits of detection were: 0.30 μg mL―1 (caffeine), 0.33 μg mL―1 (theobromine) and 0.16 μg mL―1 (theophylline). The recorded data were processed by partial least squares and artificial neural network, and the developed mathematical models were then used for prediction. The proposed, novel method was applied to determine the analytes in commercial food samples, and there were no significant differences between the results from the proposed method and those obtained by high-performance liquid chromatography.

Cognition, Cognición, Perception, Percepción, Ambiguité, Ambiguity, Ambiguedad, Cinétique, Kinetics, Cinética, Etude expérimentale, Experimental study, Estudio experimental, Identification stimulus, Stimulus identification, Identificacion estímulo, Mémoire visuelle, Visual memory, Memoria visual, Profondeur, Depth, Profundidad, Structuration d'après le mouvement, structure from motion, Estructura según moviemento, Vision, Visión, Multistabilité, Ambiguous vision, History dependence, Kinetic-depth effect, Multistable perception, Object individuation, Perceptual stability, Sensory memory of multistable perception, Structure-from-motion, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Psychologie. Psychophysiologie, Psychology. Psychophysiology, Processus d'acquisition. Mémoire, Learning. Memory, Mémoire, Memory, Homme, Human, Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychophysiology, Psychophysiologie, Psychology, psychopathology, psychiatry, and Psychologie, psychopathologie, psychiatrie

Perceptual priming can stabilize the phenomenal appearance of multistable visual displays (Leopold, Wilke, Maier, & Logothetis, Nature Neuroscience, 5, 605-609, 2002). Prior exposure to such displays induces a sensory memory of their appearance, which persists over long intervals and intervening stimulation, and which facilitates renewed perception of the same appearance. Here, we investigated perceptual priming for the apparent rotation in depth of ambiguous structure-from-motion (SFM) displays. Specifically, we generated SFM objects with different three-dimensional shapes and presented them in random order and with intervening blank periods. To assess perceptual priming, we established the probability that a perceived direction of rotation would persist between successive objects. In general, persistence was greatest between identical objects, intermediate between similar objects, and negligible between dissimilar objects. These results demonstrate unequivocally that sensory memory for apparent rotation is specific to three-dimensional shape, contrary to previous reports (e.g., Maier, Wilke, Logothetis, & Leopold, Current Biology, 13, 1076―1085, 2003). Because persistence did not depend on presentation order for any pair of objects, it provides a commutative measure for the similarity of object shapes. However, it is not clear exactly which features or aspects of object shape determine similarity. At least, we did not find simple, low-level features (such as volume overlap, heterogeneity, or rotational symmetry) that could have accounted for all observations. Accordingly, it seems that sensory memory of SFM (which underlies priming of ambiguous rotation) engages higher-level representations of object surface and shape.

Propriété biologique, Biological properties, Propiedad biológica, Acrylamide dérivé polymère, Acrylamide derivative polymer, Acrilamida derivado polímero, Activité biologique, Biological activity, Actividad biológica, Cinétique, Kinetics, Cinética, Composé chiral, Chiral compound, Compuesto quiral, Cytotoxicité, Cytotoxicity, Citotoxicidad, Dipeptide, Dipeptides, Dipéptido, Etude expérimentale, Experimental study, Estudio experimental, Fibrillation, Fibrilación, In vitro, Mécanisme action, Mechanism of action, Mecanismo acción, Nanoparticule, Nanoparticle, Nanopartícula, Polymère optiquement actif, Optically active polymer, Polímero ópticamente activo, Polymérisation dispersion, Dispersion polymerization, Polimerización dispersión, Polymérisation radicalaire, Free radical polymerization, Polimerización radicalar, Potentiel électrocinétique, Electrokinetic potential, Potencial electrocinético, Protéine amyloïde β, β Amyloid protein, Proteína amiloide β, Préparation, Preparation, Preparación, Stabilité thermique, Thermal stability, Estabilidad térmica, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Préparation, cinétique, thermodynamique, mécanisme et catalyseurs, Preparation, kinetics, thermodynamics, mechanism and catalysts, Polymères à propriétés spéciales, Polymers with particular properties, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, Polymers, paint and wood industries, and Polymères, industries des peintures et bois

Protein aggregation into amyloid fibrils is implicated in the pathogenesis of many neurodegenerative diseases. Engineered nanoparticles have emerged as a potential approach to alter the kinetics of protein fibrillation process. Yet, there are only a few reports describing the use of nanoparticles for inhibition of amyloid-β 40 (Aβ40) peptide aggregation, involved in Alzheimer's disease (AD). In the present study, we designed new uniform biocompatible amino-acid-based polymer nanoparticles containing hydrophobic dipeptides in the polymer side chains. The dipeptide residues were designed similarly to the hydrophobic core sequence of Aβ. Poly(N-acryloyl-L-phenylalanyl-L-phenylalanine methyl ester) (polyA-FF-ME) nanoparticles of 57 ± 6 nm were synthesized by dispersion polymerization of the monomer A-FF-ME in 2-methoxy ethanol, followed by precipitation of the obtained polymer in aqueous solution. Cell viability assay confirmed that no significant cytotoxic effect of the polyA-FF-ME nanoparticles on different human cell lines, e.g., PC-12 and SH-SY5Y, was observed. A significantly slow secondary structure transition from random coil to β-sheets during Aβ40 fibril formation was observed in the presence of these nanoparticles, resulting in significant inhibition of Aβ40 fibrillation kinetics. However, the polyA-FF-ME analogous nanoparticles containing the L-alanyl-L-alanine (AA) dipeptide in the polymer side groups, polyA-AA-ME nanoparticles, accelerate the Aβ40 fibrillation kinetics. The polyA-FF-ME nanoparticles and the polyA-AA-ME nanoparticles may therefore contribute to a mechanistic understanding of the fibrillation process, leading to the development of therapeutic strategies against amyloid-related diseases.

Maladie dégénérative, Degenerative disease, Enfermedad degenerativa, Pathologie de l'encéphale, Cerebral disorder, Encéfalo patología, Pathologie du système nerveux central, Central nervous system disease, Sistema nervosio central patología, Pathologie du système nerveux, Nervous system diseases, Sistema nervioso patología, Amyloïde, Amyloid, Amiloide, Cinétique, Kinetics, Cinética, Démence d'Alzheimer, Alzheimer disease, Demencia Alzheimer, Fibrille, Fibril, Fibrilla, Fluorescence, Fluorescencia, Glycoprotéine, Glycoprotein, Glicoproteína, Nitroxyle, Nitroxyl, Nitroxilo, Prion, Protéine, Protein, Proteína, Radical libre organique, Organic free radical, Radical libre orgánico, Structure dendritique, Dendritic structure, Estructura dendrítica, CD, EPR, PPI, ThT, alzheimer, fluorescence, glyco-dendrimers, nitroxide, prion, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Generalites, General aspects, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, Pharmacology drugs, and Pharmacologie, galénique

The aggregation behavior of the amyloid peptide Aβ1-28 and the prion peptide PrP185-208 - both responsible for neurodegenerative disorders ― was analyzed in the absence and in the presence of poly(propylene imine) (PPI) dendrimers at generation 5 (G5) with a dense shell of maltose and maltotriose units. Thioflavin T (ThT) fluorescence assay and circular dichroism (CD) experiments indicated that fibril formation is enhanced at low dendrimer concentration, while it is prevented at relatively high dendrimer concentrations. Computer aided EPR analysis by means of the selected spin probe 4-octyl-dimethylammonium,2,2,6,6-tetramethyl-piperidine-1-oxyl bromide (CAT8) further demonstrated this behavior, but also provided detailed information on the mechanism of fibril formation and on the different behavior of the differently decorated dendrimers. The CAT8 radicals were progressively trapped at the peptide interphase when peptide aggregates were formed, also monitoring pre-fibrillar structures. At later time, a phase separation of the CAT8 radicals monitors the formation of further supramolecular structures where the probes become squeezed among fibrillar aggregates. The addition of small amounts of dendrimers promotes the formation of peptide fibrils breaking them and providing a larger amount of ends that serve as sites of replications. Conversely, a high amount of dendrimers allows the peptides to well separate from each other such preventing their aggregation. EPR results also indicate that the perturbation played by PPI(G5)-Maltose are more effective onto PrP185-208 than onto Aβ1-28, while PPI(G5)-Maltotriose is less effective towards PrP185-208 in both promoting aggregation and preventing it by changing the dendrimer concentration. These results provide useful information about the mechanism and interactions which regulate the ability of macromole-cules like the dendrimers to favor, prevent or cure neurodegenerative diseases.

Analyse thermique, Thermal analysis, Análisis térmico, Cinétique, Kinetics, Cinética, Citation, Citación, Facteur impact, Impact factor, Factor impacto, Littérature scientifique, Scientific literature, Literatura científica, Science information, Information science, Ciencia información, Best cited papers, Quotation responses, Thermoanalytical journals, Sciences exactes et technologie, Exact sciences and technology, Sciences et techniques communes, Sciences and techniques of general use, Sciences de l'information. Documentation, Information science. Documentation, Sciences de l'information et des bibliothèques. Etude d'ensemble, Library and information science. General aspects, Bibliométrie. Scientométrie. Evaluation, Bibliometrics. Scientometrics. Evaluation, Sciences de l'information et de la communication, Information and communication sciences, Bibliométrie. Scientométrie, Bibliometrics. Scientometrics, General chemistry, physical chemistry, and Chimie générale, chimie physique

Extent of citation is analysed and the best citied papers mentioned accentuating Journal of Thermal analysis and Thermochimica Acta. The relevant scope of papers is uncovered and some viewpoints are shown. The sphere of kinetics appears the most cited subject matter.

Chlore Composé organique, Chlorine Organic compounds, Cloro Compuesto orgánico, Enzyme, Enzima, Mammalia, Oxidoreductases, Rodentia, Vertebrata, Amine oxidase (flavin-containing), Aminoéther, Aminoether, Aminoeter, Animal, Antidépresseur, Antidepressant agent, Antidepresor, Cinétique, Kinetics, Cinética, Dépendance du temps, Time dependence, Dependencia del tiempo, Dérivé du benzène, Benzene derivatives, Benceno derivado, Homme, Human, Hombre, In vitro, Inhibiteur de la monoamine oxidase A, Monoamine oxidase A inhibitor, Inhibidor monoamine oxidase A, Inhibiteur enzyme, Enzyme inhibitor, Inhibidor enzima, Inhibition non compétitive, Non competitive inhibition, Inhibición no competitiva, Liaison covalente, Covalent bond, Enlace covalente, Neurotoxicité, Neurotoxicity, Neurotoxicidad, Psychotrope, Psychotropic, Psicotropo, Relation structure activité, Structure activity relation, Relación estructura actividad, Réaction réversible, Reversible reaction, Reacción reversible, Sodium Tétrahydroborate, Sodium Tetrahydroborates, Sodio Borohidruro, Souris, Mouse, Ratón, Synthèse chimique, Chemical synthesis, Síntesis química, Système nerveux, Nervous system, Sistema nervioso, Toxicité, Toxicity, Toxicidad, Pyridine(1-[3-(2,4-dichlorophénoxy)propyl]-1,2,3,6-tétrahydro), Covalent, Monoamine oxidase, Sodium borohydride, Tetrahydropyridine, Time-dependent inhibition, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, Pharmacology drugs, and Pharmacologie, galénique

A novel class of N-substituted tetrahydropyridine derivatives was found to have multiple kinetic mechanisms of monoamine oxidase A inhibition. Eleven structurally similar tetrahydropyridine derivatives were synthesized and evaluated as inhibitors of MAO-A and MAO-B. The most potent MAO-A inhibitor in the series, 2,4-dichlorophenoxypropyl analog 12, displayed time-dependent mixed noncompetitive inhibition. The inhibition was reversed by dialysis, indicating reversible enzyme inhibition. Evidence that the slow-binding inhibition of MAO-A with 12 involves a covalent bond was gained from stabilizing a covalent reversible intermediate product by reduction with sodium borohydride. The reduced enzyme complex was not reversible by dialysis. The results are consistent with slowly reversible, mechanism-based inhibition. Two tetrahydropyridine analogs that selectively inhibited MAO-A were characterized by kinetic mechanisms differing from the kinetic mechanism of 12. As reversible inhibitors of MAO-A, tetrahydropyridine analogs are at low risk of having an adverse effect of tyramine-induced hypertension.

Carboxylic ester hydrolases, Enzyme, Enzima, Esterases, Hydrolases, Oxidoreductases, Acetylcholinesterase, Amine oxidase (flavin-containing), Antialzheimer, Antialzheimer agent, Anticholinestérasique, Anticholinesterase agent, Anticolinesterasa agente, Cholinesterase, Cinétique, Kinetics, Cinética, Complexe enzyme inhibiteur, Inhibitor enzyme complex, Complejo enzima inhibidor, Composé acétylénique, Acetylenic compound, Compuesto acetilénico, Composé bicyclique, Bicyclic compound, Compuesto bicíclico, Cycle 6 chaînons, Six membered ring, Ciclo 6 eslabones, Dérivé de la pipéridine, Piperidine derivatives, Piperidina derivado, Hétérocycle azote, Nitrogen heterocycle, Heterociclo nitrógeno, IMAO, MAO inhibitor, In vitro, Inhibiteur de la monoamine oxidase A, Monoamine oxidase A inhibitor, Inhibidor monoamine oxidase A, Inhibiteur de la monoamine oxidase B, Monoamine oxidase B inhibitor, Inhibidor monoamine oxidase B, Inhibiteur enzyme, Enzyme inhibitor, Inhibidor enzima, Mode liaison, Binding mode, Modo de enlace, Modèle moléculaire, Molecular model, Modelo molecular, Modélisation, Modeling, Modelización, Mécanisme action, Mechanism of action, Mecanismo acción, Nitrile, Nitrilo, Relation structure activité, Structure activity relation, Relación estructura actividad, Synthèse chimique, Chemical synthesis, Síntesis química, Sélectivité, Selectivity, Selectividad, 1,8-Naphtyridine-3-carbonitrile dérivé, Pyridine-3,5-dicarbonitrile dérivé, AChE, Alzheimer's disease, BuChE, Inhibition mechanism, Kinetic analysis, MAO-A, MAO-B, Molecular modeling, Multipotent molecules, Naphthyridines, Pyridines, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Organic chemistry, Chimie organique, Pharmacology drugs, and Pharmacologie, galénique

The synthesis, biological evaluation and molecular modeling of new multipotent inhibitors of type I and type II, able to simultaneously inhibit monoamine oxidases (MAO) as well as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), is described. Compounds of type I were prepared by sequential reaction of 2,6-dichloro-4-phenylpyridine-3,5-dicarbonitrile (14) [or 2,6-dichloropyridine-3, 5-dicarbonitrile (15)] with prop-2-yn-1-amine (or N-methylprop-2-yn-1-amine) and 2-(1-benzyl-piperidin-4-yl)alkylamines 22—25. Compounds of type II were prepared by Friedländer type reaction of 6-amino-5-formyl-2-(methyl(prop-2-yn-1-yl)amino)nicotinonitriles 32 and 33 with 4-(1-benzylpiperidin-4-yl)butan-2-one (31). The biological evaluation of molecules 1―11 showed that most of these compounds are potent, in the nanomolar range, and selective AChEI, with moderate and equipotent selectivity for MAO-A and MAO-B inhibition. Kinetic studies of compound 8 proved that this is a EeAChE mixed type inhibitor (IC50 = 16 ± 2; Ki = 12 ± 3 nM). Molecular modeling investigation on compound 8 confirmed its dual AChE inhibitory profile, binding simultaneously at the catalytic active site (CAS) and at the peripheric anionic site (PAS). In overall, compound 11, as a potent and selective dual AChEI, showing a moderate and selective MAO-A inhibitory profile, can be considered as an attractive multipotent drug for further development on two key pharmacological targets playing key roles in the therapy of Alzheimer's disease.

Carboxylic ester hydrolases, Enzyme, Enzima, Esterases, Hydrolases, Acetylcholinesterase, Antialzheimer, Antialzheimer agent, Anticholinestérasique, Anticholinesterase agent, Anticolinesterasa agente, Cholinesterase, Cinétique, Kinetics, Cinética, Composé tricyclique, Tricyclic compound, Compuesto tricíclico, Composé tétracyclique, Tetracyclic compound, Compuesto tetracíclico, Hétérocycle azote, Nitrogen heterocycle, Heterociclo nitrógeno, In vitro, Inhibiteur enzyme, Enzyme inhibitor, Inhibidor enzima, Neuroprotecteur, Neuroprotective agent, Neuroprotector, Relation structure activité, Structure activity relation, Relación estructura actividad, Stress oxydatif, Oxidative stress, Estrés oxidativo, Synthèse chimique, Chemical synthesis, Síntesis química, Benzo[b]pyrazolo[4,3-g][1,8]naphtyridine dérivé, Pyrazolo[3,4-b]quinoléine dérivé, Pyrazoloquinoléine, AChE/BuChE inhibitors, Alzheimer's disease, Neuroprotection, Pyrazolotacrines, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psychoanaleptiques: stimulant snc, antidépresseur, nootrope, normothymique..., (maladie d'alzheimer), Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease), Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psychoanaleptiques: stimulant SNC antidépresseur, nootrope, normothymique…, Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer…, Organic chemistry, Chimie organique, Pharmacology drugs, and Pharmacologie, galénique

The synthesis and pharmacological analyses of a number of pyrazolo[3,4-b]quinoline and benzo[b]pyrazolo[4,3-g][1,8]naphthyridine derivatives are reported. We have synthesized the diversely substituted tacrine analogues 1—6, by Friedländer-type reaction of readily available o-amino-1-methyl-pyrazoledicarbonitriles with cyclohexanone. The biological evaluation showed that pyrazolotacrines 1―6 are inhibitors of Electrophorus electricus acetylcholinesterase (EeAChE), in the micromolar range, and quite selective in respect to serum horse butyrylcholinesterase (eqBuChE) inhibition; the most interesting inhibitor is N-(5-amino-1-methyl-6,7,8,9-tetrahydro-1H-benzo[b]pyrazolo[4,3-g][1,8]naphthyridin-3-yl) acetamide (5) [IC50 (EeAChE) = 0.069 ± 0.006 μM; IC50 (eqBuChE) = 6.3 ± 0.6 μM]. Kinetic studies showed that compound 5 is a mixed-type inhibitor of EeAChE (Ki = 155 nM). Inhibitor 5 showed a 45% neuroprotection value against rotenone/oligomycin A-induced neuronal death.

Maladie de système, Systemic disease, Enfermedad sistémica, Maladie héréditaire, Genetic disease, Enfermedad hereditaria, Pathologie de la peau, Skin disease, Piel patología, Pathologie du système ostéoarticulaire, Diseases of the osteoarticular system, Sistema osteoarticular patología, Pathologie du tissu élastique, Elastic tissue disease, Tejido elástico patología, Traitement, Treatment, Tratamiento, Allure, Gait, Marcha, Analyse quantitative, Quantitative analysis, Análisis cuantitativo, Association morbide, Concomitant disease, Asociación morbosa, Cinématique, Kinematics, Cinemática, Cinétique, Kinetics, Cinética, Evaluation, Evaluación, Homme, Human, Hombre, Rigidité, Stiffness, Rigidez, Rééducation, Reeducation, Reeducación, Stratégie, Strategy, Estrategia, Syndrome d'Ehlers-Danlos, Ehlers-Danlos syndrome, Piel elástica, Hyperlaxité articulaire, Joint hypermobility, Hiperlaxitud articular, Ehlers-Danlos, Rehabilitation, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Sarcoidoses. Granulomatoses d'etiologie indeterminee. Maladies du tissu conjonctif. Maladies du tissu elastique. Vascularites, Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis, Psychopathologie. Psychiatrie, Psychopathology. Psychiatry, Thérapeutiques, Treatments, Rééducation. Réadaptation. Sociothérapie, Reeducation. Readaptation. Sociotherapy, Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, PSYCHOPATHOLOGIE. PSYCHIATRIE, Cognition, Psychology, psychopathology, psychiatry, and Psychologie, psychopathologie, psychiatrie

The aim of this study was to quantify the gait patterns of adults with joint hypermobility syndrome/Ehlers-Danlos syndrome (JHS/EDS-HT) hypermobility type, using Gait Analysis. We quantified the gait strategy in 12 JHS/EDS-HT adults individuals (age: 43.08 + 6.78 years) compared to 20 healthy controls (age: 37.23 ± 8.91 years), in terms of kinematics and kinetics. JHS/EDS-HT individuals were characterized by a non-physiological gait pattern. In particular, spatio-temporal parameters evidenced lower anterior step length and higher stance phase duration in JHS/EDS-HT than controls. In term of kinematics, in JHS/EDS-HT patients the main gait limitations involved pelvis, distal joints and ankle joint. Conversely, hip and knee joint showed physiological values. Ankle moment and power revealed reduced peak values during terminal stance. Differences in stiffness at hip and ankle joints were found between JHS/EDS-HT and controls. JHS/EDS-HT patients showed significant decreased of Kh and Ka parameters very probably due to congenital hypotonia and ligament laxity. These findings help to elucidate the complex biomechanical changes in JHS/EDS-HT and may have a major role in the multidimensional evaluation and tailored management of these patients.

Artiodactyla, Dérivé de la phénothiazine, Phenothiazine derivatives, Fenotiazina derivado, Mammalia, Ungulata, Vertebrata, Analyse chimique, Chemical analysis, Análisis químico, Analyse quantitative, Quantitative analysis, Análisis cuantitativo, Analyse trace, Trace analysis, Análisis huella, Animal, Bovin, Bovine, Bovino, Chlorpromazine, Clorpromazina, Chromatographie HPLC, HPLC chromatography, Cromatografía HPLC, Cinétique, Kinetics, Cinética, Détecteur UV, Ultraviolet detector, Detector UV, Enrichissement chimique, Chemical enrichment, Enriquecimiento químico, Fixation biologique, Biological fixation, Fijación biológica, Hétérocycle soufre azote, Sulfur nitrogen heterocycle, Heterociclo azufre nitrógeno, Interaction moléculaire, Molecular interaction, Interacción molecular, Microextraction phase solide, Solid phase microextraction, Microextracción fase sólida, Neuroleptique, Neuroleptic, Neuroléptico, Protéine sérique, Serum protein, Proteína sérica, Préparation échantillon, Sample preparation, Preparación muestreo, Psychotrope, Psychotropic, Psicotropo, Sérumalbumine, Serum albumin, Seroalbúmina, Isotherme de fixation, Binding isotherm, Albumin, Free concentration, nd-SPME, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pharmacologie. Traitements medicamenteux, Pharmacology. Drug treatments, Neuropharmacologie, Neuropharmacology, Psycholeptiques: tranquillisant, neuroleptique., Psycholeptics: tranquillizer, neuroleptic., Psychologie. Psychanalyse. Psychiatrie, Psychology. Psychoanalysis. Psychiatry, Psychopharmacologie, Psychopharmacology, Psycholeptiques: tranquillisant, neuroleptique…, Psycholeptics: tranquillizer, neuroleptic…, Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, Analytical chemistry, Chimie analytique, Pharmacology drugs, Pharmacologie, galénique, and Pollution

The addition of proteins to in vitro systems influences the free concentration of the test compound in the medium. The objective of this study was to set up a negligible depletion-solid phase microextraction method, coupled to high-performance liquid chromatography (nd-SPME - HPLC) to measure the free concentration of chlorpromazine (CPZ) in medium containing albumin. The nd-SPME method was optimized for coating thickness (polyacrylate coating) and exposure time, and potential effects from the addition of bovine serum albumin (BSA) were studied. It was shown that the addition of albumin did not cause fouling or influenced the uptake kinetics of CPZ into the fiber. At a realistic in vivo albumin concentration of 40g/L of albumin, 94% of CPZ was protein bound. This is in line with findings in vivo, reporting a protein binding for CPZ of 92―99%. The nd-SPME - HPLC method described in this study can be used to measure the free concentration of chlorpromazine in medium containing proteins. These findings can be used to correct in vitro data for protein binding of chlorpromazine and this information is essential for the extrapolation to in vivo data.