Publications by authors named "Luis Lemus"

Interception, essential for activities like driving and sports, can be characterized by varying degrees of predictive behaviour. We developed a visually guided task to explore how target predictability and visibility influenced interception actions. The task featured a falling dot influenced by horizontal velocity, gravity and air friction, with predictability manipulated through external forces that altered the target's trajectory.

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Tetanus is a vaccine-preventable disease that commonly occurs in under-resourced countries; clinically, it manifests as spontaneous muscle spasms and overall body rigidity, which can lead to autonomic dysfunction. The diagnosis of tetanus is primarily clinical, although laboratory testing is available, treatment of a clinical case should never be delayed. Management includes general support measures, prevention of complications, control of muscle spasms, and immunoglobulin.

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A series of six new Cu(i) complexes with ([Cu(-{4-}pyridine-2-yl-methanimine)(PPh)Br]) formulation, where corresponds to a donor or acceptor -substituent, have been synthesized and were used to study self-association effects on their structural and electrochemical properties. X-ray diffraction results showed that in all complexes the packing is organized from a dimer generated by supramolecular π stacking and hydrogen bonding. H-NMR experiments at several concentrations showed that all complexes undergo a fast-self-association monomer-dimer equilibrium in solution, while changes in resonance frequency towards the high or low field in specific protons of the imine ligand allow establishing that dimers have similar structures to those found in the crystal.

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Neck masses are a very common clinical problem and it remains a diagnostic challenge due to multiple differential diagnoses ranging from benign to severe etiologies. All physicians should equip themselves with knowledge of common and locally prevalent causes of neck masses and manage them accordingly. We present a case of a young patient with no prior medical history who developed cervical tuberculous lymphadenitis.

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Wolff-Parkinson-White (WPW) syndrome is rare and is characterized by an accessory pathway that predisposes patients to tachyarrhythmias and sudden cardiac death. Early recognition is important and should be evaluated by a multidisciplinary team for adequate management and treatment. We present a pregnant woman that presented to the emergency department and discuss her diagnosis, treatment, and outcome.

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The main goal of this work was to screen the antiproliferative activity and mechanism of actions of two copper complexes: [Cu(dmp)(CHCN)] (1) and [Cu(phen)(CHCN)] (2) on 2D and 3D colorectal cancer cells models. Cell viability studies on three colorectal cancer cell lines (HT-29, LS174T, Caco-2) displayed that 1 showed more robust antiproliferative activity than 2 and cisplatin. Intracellular copper content (63.

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In social animals, identifying sounds is critical for communication. In humans, the acoustic parameters involved in speech recognition, such as the formant frequencies derived from the resonance of the supralaryngeal vocal tract, have been well documented. However, how formants contribute to recognizing learned sounds in non-human primates remains unclear.

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Improving the binding of metal complexes to DNA to boost cancer cell cytotoxicity requires fine tuning of their structural and chemical properties. Copper has been used as a metal center in compounds containing intercalating ligands due to its ability to catalytically generate reactive oxygen species (ROS), such as hydroxyl radicals (OH˙). We envision the synergy of DNA binding and ROS generation in proximity to target DNA as a powerful chemotherapy treatment.

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Epithelioid angiosarcoma is a rare and very aggressive malignant tumor with high rates of metastasis and recurrence that can present in any part of the body, with the head and neck being the most common regions. Wide-margin surgical resection is the treatment of choice following radiotherapy due to the high rate of recurrence. We present a case of an elderly patient who developed angiosarcoma causing spinal cord compression at the level of C7 vertebrae.

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In human speech and communication across various species, recognizing and categorizing sounds is fundamental for the selection of appropriate behaviors. However, how does the brain decide which action to perform based on sounds? We explored whether the supplementary motor area (SMA), responsible for linking sensory information to motor programs, also accounts for auditory-driven decision making. To this end, we trained two rhesus monkeys to discriminate between numerous naturalistic sounds and words learned as target (T) or non-target (nT) categories.

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Time-resolved X-ray (tr-XAS) and optical transient absorption (OTA) spectroscopy in the picosecond time scale coupled with Density Functional theory (DFT) and X-ray absorption near-edge structure (XANES) calculations are applied to study three homoleptic Cu(i) dimeric chromophores with ethyl and longer propyl spacers, denoted as [Cu(mphenet)]Cl (C1), [Cu(mphenet)](ClO) (C2) and [Cu(mphenpr)](ClO) (C3) (where mphenet = 1,2-bis(9-methyl-1,10-phenanthrolin-2-yl)ethane and mphenpr = 1,3-bis(9-methyl-1,10-phenanthrolin-2-yl)propane). Tr-XAS analysis after light illumination at ∼ 100 ps illustrate the formation of a flattened triplet excited state in all 3 complexes. Optical transient absorption (OTA) analysis for C1 monitored in water and C2 and C3 measured in acetonitrile reveals distinct excited-state lifetimes of 169 ps, 670 ps and 1600 ps respectively.

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The relation between redox activity and coordination geometry in CuN complexes indicates that more flattened structures tend to be more reactive. Such a preorganization of the ligand confers to the complex geometries closer to a transition state, which has been termed the "entatic" state in metalloproteins, more recently extending this concept for copper complexes. However, many aspects of the redox chemistry of Cu complexes cannot be explained only by flattening.

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In the design of self-assembled compounds, small variations in the linkers connecting the coordinating moieties can produce large differences in the obtained structures. Here, we report three novel zinc(II) complexes with phenanthroline-derived ligands as building blocks (-): A mononuclear complex, a bimetallic helicate, and a trimetallic circular helicate. The even-number spacer in promotes the formation of a bimetallic helicate stabilized by π-π interactions of adjacent phenanthrolines.

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This work presents the results obtained for a thioether derivative of bipyridine, (E,Z)-1-(4'-methyl-[2,2'-bipyridine]-4-yl)-N-(4(methylthio)phenyl)methanimine (4-mbpy-Bz-SMe), and its copper complex [Cu(4-mbpy-Bz-SMe)]. Electronic spectra acquired at 183 K of the cuprous complex [Cu(4-mbpy-Bz-SMe)] generated in situ indicated the formation of the peroxodicopper compound {[Cu(4-mbpy-Bz-SMe)](μ-O)}. A gold electrode modified with [Cu(4-mbpy-Bz-SMe)] (Au/[Cu]) was fully characterized by SERS spectroscopy, electrochemistry and impedance spectroscopy thus showing adsorption occurs through the sulfur atom of the 4-mbpy-Bz-SMe moieties.

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We provide a procedure for a psychophysics experiment in humans based on a previously described paradigm aimed to characterize the perceptual duration of intervals within the range of milliseconds of visual, acoustic, and audiovisual aperiodic trains of six pulses. In this task, each of the trials consists of two consecutive intramodal intervals where the participants press the upward arrow key to report that the second stimulus lasted longer than the reference, or the downward arrow key to indicate otherwise. The analysis of the behavior results in psychometric functions of the probability of estimating the comparison stimulus to be longer than the reference, as a function of the comparison intervals.

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Magnetic nanoparticles have been extensively explored for the development of platforms for drug delivery and imaging probes. In this work, we have used a modular capping strategy to produce magnetic gold-coated FeO (FeO@Au) nanoparticles, which have been decorated with a copper (II) complex containing a thioether derivative of clip-phen (FeO@Au@Cu), where the complex [Cu(2CP-Bz-SMe)] has affinity to bind DNA and proven nuclease activity (2CP-Bz-SMe=1,3-bis((1,10-phenanthrolin-2-yl)oxy)-N-(4-(methylthio)benzylidene)propan-2-imine). The functionalization of FeO@Au with the copper complex occurs through the sulfur atom of the thioether moiety, as indicated by Raman scattering on surface.

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A family of six homoleptic [Cu (L )] (ClO ) and six heteroleptic [Cu (L )(PPh ) ] (ClO ) bimetallic complexes, in which L are bis-Schiff base ligands with alkyl spacers of variable length (n=2-7 -CH -), were prepared to evaluate the role of the spacer on the formation of helicates or mesocates. In the homoleptic series, spectroscopic and theoretical studies indicate that preferences for a conformation are based on energetic parameters, mainly, the establishment of noncovalent interactions. The odd-even nature of the spacers preconditions the superposition of the aromatic rings to allow the juxtaposition necessary for noncovalent interactions, whereas the increase of the length reduces the strength of such interactions.

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Previous work on perceptual decision making in the sensorimotor system has shown population dynamics in the beta band, corresponding to the encoding of stimulus properties and the final decision outcome. Here, we asked how oscillatory dynamics in the medial premotor cortex (MPC) contribute to supramodal perceptual decision making. We recorded local field potentials (LFPs) and spikes in two monkeys trained to perform a tactile-acoustic frequency discrimination task, including both unimodal and crossmodal conditions.

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A set of new copper(i) complexes is synthesized and characterized using a labile PNP pincer ligand (PNP = N,N'-bis(diphenylphosphine)-2,6-diaminopyridine). A homoleptic Cu(i) complex [Cu(PNP-κP:κN)], (1), was prepared, and taking advantage of the uncoordinated phosphorus atoms in (1), reaction with a second Cu(i) atom bearing secondary ligands (PPh, phen or dmp) allows the formation of new complexes: a bimetallic helicate [Cu(PNP)(phen)], (2), a mononuclear pincer complex [Cu(PNP)(PPh)], (3), and a heteroleptic complex [Cu(PNP)(dmp)], (4). All complexes were characterized by X-ray crystallography, NMR (VT-NMR for (1) and (4)), cyclic-voltammetry, and steady-state and time-resolved luminescence spectroscopy.

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The ability to estimate time intervals subserves many of our behaviors and perceptual experiences. However, it is not clear how aperiodic (AP) stimuli affect our perception of time intervals across sensory modalities. To address this question, we evaluated the human capacity to discriminate between two acoustic (A), visual (V) or audiovisual (AV) time intervals of trains of scattered pulses.

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The family of Transient Receptor Potential (TRP) ion channels is constituted by 7 subfamilies among which are those that respond to temperature, the thermoTRPs. These channels are versatile molecules of a polymodal nature that have been shown to be modulated in various fashions by molecules of a lipidic nature. Some of these molecules interact directly with the channels on specific regions of their structures and some of these promote changes in membrane fluidity or modify their gating properties in response to their agonists.

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Coordination compounds of copper have been invoked as major actors in processes involving the reduction of molecular oxygen, mostly with the generation of radical species the assignment for which has, so far, not been fully addressed. In the present work, we have carried out studies in solution and on surfaces to gain insights into the nature of the radical oxygen species (ROS) generated by a copper(II) coordination compound containing a thioether clip-phen derivative, 1,3-bis(1,10-phenanthrolin-2-yloxy)-N-(4-(methylthio)benzylidene)propan-2-amine (2CP-Bz-SMe), enabling its adsorption/immobilization to gold surfaces. Whereas surface plasmon resonance (SPR) and electrochemistry of the adsorbed complex indicated the formation of a dimeric Cu(I) intermediate containing molecular oxygen as a bridging ligand, scanning electrochemical microscopy (SECM) and nuclease assays pointed to the generation of a ROS species.

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