79 research outputs found

    Scatter Plot 3D

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    Las computadoras, Internet, y la Web generan continuamente una cantidad de datos que crece dramáticamente. Ante esta cantidad abrumadora de información surge la necesidad de transformar los datos en información que sea útil para quien debe usarla. De la necesidad de estudiar y obtener técnicas efectivas para comunicar información a través de imágenes nace la Visualización. Una herramienta de Visualización ampliamente utilizada para estudiar las relaciones entre los diferentes atributos de los items presentes en un conjunto de datos es el Scatter Plot. Un Scatter Plot 2D consiste en una representación gráfica utilizada en estadística para mostrar y comparar dos o más conjuntos de datos en cantidades finitas, teniendo una coordenada en el eje horizontal (X) y otra en el eje vertical (Y), presentando la información a partir de una distribución bivariada. Resulta importante poder representar items de datos definidos a partir de tuplas cuya dimensionalidad sea superior a dos, en cuyo caso surge la necesidad de contar con un mapeo visual mas rico para poder soportar los atributos de los items de datos. En base a lo expuesto resulta útil diseñar una técnica de Scatter Plot 3D capaz de representar una mayor cantidad de valores por dato haciendo, por un lado, uso de la tercera dimensión para mapear un valor al tercer eje y enfatizando la explotación de las propiedades gráficas del elemento de representación utilizado. Se propone entonces el uso de Glifos como elemento de representación en un Scatter Plot 3D,aumentando potencialmente la dimensionalidad del mapeo visual

    Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(II) and palladium(II).

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    The synthesis, spectroscopic and X-ray structural characterization of copper(II) and palladium(II) complexes with aziridine ligands as 2-dimethylaziridine HNCH2CMe2 (a), the bidentate N-(2-aminoethyl)aziridines C2H4NC2H4NH2 (b) or CH2CMe2NCH2CMe2NH2 (c) as well as the unsaturated azirine NCH2CPh (d) are reported. Cleavage of the cyclometallated Pd(II) dimer [μ-Cl(C6H4CHMeNMe2-C,N)Pd]2 with ligand a yielded compound [Cl(NHCH2CMe2)(C6H4CHMe2NMe2-C,N)Pd] (1a). The reaction of the aziridine complex trans-[Cl2Pd(HNC2H4)2] with an excess of aziridine in the presence of AgOTf gave the ionic chelate complex trans-[(C2H4NC2H4NH2-N,N′)2Pd](OTf)2 (2b) which contains the new ligand b formed by an unexpected insertion and ring opening reaction of two aziridines (“aziridine dimerization”). CuCl2 reacted in pure HNC2H4 or HNCH2CMe2 (b) again by “dimerization” to give the tris-chelated ionic complex [Cu(C2H4NC2H4NH2-N,N′)3]Cl2 (3b) or the bis-chelated complex [CuCl(C2H2Me2NC2H2Me2NH2-N,N′)2]Cl (4c). By addition of 2H-3-phenylazirine (d) to PdCl2, trans-[Cl2Pd(NCH2CPh)2] (5d) was formed. All new compounds were characterized by NMR, IR and mass spectra and also by X-ray structure analyses (except 3b). Additionally the cytotoxic effects of these complexes were examined on HL-60 and NALM-6 human leukemia cells and melanoma WM-115 cells. The antimicrobial activity was also determined. The growth of Gram-positive bacterial strains (S. aureus, S. epidermidis, E. faecalis) was inhibited by almost all tested complexes at the concentrations of 37.5–300.0 μg mL−1. However, MIC values of complexes obtained for Gram-negative E. coli and P. aeruginosa, as well as for C. albicans yeast, mostly exceeded 300 μg mL−1. The highest antibacterial activity was achieved by complexes 1a and 2b. Complex 2b also inhibited the growth of Gram-negative bacteria. Graphical abstract: Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(ii) and palladium(ii

    Collision sellar lesions: experience with eight cases and review of the literature

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    The concomitant presence of a pituitary adenoma with a second sellar lesion in patients operated upon for pituitary adenoma is an uncommon entity. Although rare, quite a great variety of lesions have been indentified coexisting with pituitary adenomas. In fact, most combinations have been described before, but an overview with information on the frequency of combined pathologies in a large series has not been published. We present a series of eight collision sellar lesions indentified among 548 transsphenoidally resected pituitary adenomas in two Neurosurgical Departments. The histological studies confirmed a case of sarcoidosis within a non-functioning pituitary adenoma, a case of intrasellar schwannoma coexisting with growth hormone (GH) secreting adenoma, two Rathke’s cleft cysts combined with pituitary adenomas, three gangliocytomas associated with GH-secreting adenomas, and a case of a double pituitary adenoma. The pertinent literature is discussed with emphasis on pathogenetic theories of dual sellar lesions. Although there is no direct evidence to confirm the pathogenetic relationship of collision sellar lesions, the number of cases presented in literature makes the theory of an incidental occurrence rather doubtful. Suggested hypotheses about a common embryonic origin or a potential interaction between pituitary adenomas and the immune system are presented

    Clinical Trials in Head Injury

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    Traumatic brain injury (TBI) remains a major public health problem globally. In the United States the incidence of closed head injuries admitted to hospitals is conservatively estimated to be 200 per 100,000 population, and the incidence of penetrating head injury is estimated to be 12 per 100,000, the highest of any developed country in the world. This yields an approximate number of 500,000 new cases each year, a sizeable proportion of which demonstrate signficant long-term disabilities. Unfortunately, there is a paucity of proven therapies for this disease. For a variety of reasons, clinical trials for this condition have been difficult to design and perform. Despite promising pre-clinical data, most of the trials that have been performed in recent years have failed to demonstrate any significant improvement in outcomes. The reasons for these failures have not always been apparent and any insights gained were not always shared. It was therefore feared that we were running the risk of repeating our mistakes. Recognizing the importance of TBI, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored a workshop that brought together experts from clinical, research, and pharmaceutical backgrounds. This workshop proved to be very informative and yielded many insights into previous and future TBI trials. This paper is an attempt to summarize the key points made at the workshop. It is hoped that these lessons will enhance the planning and design of future efforts in this important field of research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63185/1/089771502753754037.pd

    A large topographic feature on the surface of the trans-Neptunian object (307261) 2002 MS4_4 measured from stellar occultations

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    This work aims at constraining the size, shape, and geometric albedo of the dwarf planet candidate 2002 MS4 through the analysis of nine stellar occultation events. Using multichord detection, we also studied the object's topography by analyzing the obtained limb and the residuals between observed chords and the best-fitted ellipse. We predicted and organized the observational campaigns of nine stellar occultations by 2002 MS4 between 2019 and 2022, resulting in two single-chord events, four double-chord detections, and three events with three to up to sixty-one positive chords. Using 13 selected chords from the 8 August 2020 event, we determined the global elliptical limb of 2002 MS4. The best-fitted ellipse, combined with the object's rotational information from the literature, constrains the object's size, shape, and albedo. Additionally, we developed a new method to characterize topography features on the object's limb. The global limb has a semi-major axis of 412 ±\pm 10 km, a semi-minor axis of 385 ±\pm 17 km, and the position angle of the minor axis is 121 ^\circ ±\pm 16^\circ. From this instantaneous limb, we obtained 2002 MS4's geometric albedo and the projected area-equivalent diameter. Significant deviations from the fitted ellipse in the northernmost limb are detected from multiple sites highlighting three distinct topographic features: one 11 km depth depression followed by a 255+4^{+4}_{-5} km height elevation next to a crater-like depression with an extension of 322 ±\pm 39 km and 45.1 ±\pm 1.5 km deep. Our results present an object that is \approx138 km smaller in diameter than derived from thermal data, possibly indicating the presence of a so-far unknown satellite. However, within the error bars, the geometric albedo in the V-band agrees with the results published in the literature, even with the radiometric-derived albedo
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