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CONTEXT: The electron localization is a concept that allows scientists to better understand the physical and chemical properties of electronic systems. It is associated with the propensity of electron pairs with opposite spins to accumulate as well as with their response to external perturbations. This paper contains a detailed description of the design and implementation of the program KLD, which was primarily developed in our research group to elucidate electron localization in molecular systems by evaluating the information content of electron-pair density functions. KLD employs two information-based functions as a real space measure of the Fermi and Coulomb holes for same-spin electrons and shows a better resolution as compared to other methods (i.e., ELF). Information about the acceleration of the code is also included in the present work, being noticeable the reduction of wall-time calculation and the error calculation between versions. METHODS: KLD was designed to be easy to use, extend, and maintain; thus, many principles of modern software development, extensive testing, and package management were adopted. The latest version of the KLD program was created utilizing the Compute Unified Device Architecture (CUDA) version, which allows it to use the computational capacity of NVIDIA Graphics Processing Units (GPUs) for processing purposes. The electron-pair conditional density was calculated from the canonical molecular orbitals obtained at the HF/6-31G(2df,p) level, or alternatively the natural orbitals in the case of explicit correlated wavefunctions computed at the MP2/6-31G(2df,p)//HF/6-31G(2df,p) level.

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This work delves into the bonding nature of the pentagonal-pyramidal benzene and hexamethylbenzene dications, C6R62+ (R = H and CH3), which contain a hexacoordinate carbon. The study employs a range of methodologies to analyze a series of scalar fields, including electron density, electron localization function, local momentum representation, and the evaluation of the Coulomb hole through information theory-derived functions. The findings unveil that electron density undergoes transfer from the pentagonal ring to the apical group. As a result, the base of the complex accumulates the positive charge. Moreover, an extended electron density domain emerges between the carbon pentagon and the apical carbon atom. This phenomenon is related to the molecular orbitals with a dipolar character aligned with the principal axis of the molecule. The results also indicate an electron density polarization towards the apical carbon, coupled with an exclusion of electron density surrounding both the apical carbon and the lower portion of the pentagonal ring. These provide valuable insights into the complex bonding nature of hexacoordinate carbon and its implications for organic chemistry.

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The C-X bond cleavage in different methyl halides (CH3X; X = Cl, Br, I) mediated by 5,6-dimethylbenzimidazole-bis(dimethylglyoximate)cobalt(II) (CoIICbx) was theoretically investigated in the present work. An SN2-like mechanism was considered to simulate the chemical process where the cobalt atom acts as the nucleophile and the halogen as the leaving group. The reaction path was computed by means of the intrinsic reaction coordinate method and analyzed in detail through the reaction force formalism, the quantum theory of atoms in molecules (QTAIM), and the calculation of one-electron density derived quantities, such as the source function (SF) and the spin density. A thorough comparison of the results with those obtained in the same reaction occurring in presence of 5,6-dimethylbenzimidazole-bis(dimethylglyoximate)cobalt(I) (CoICbx) was conducted to reveal the main differences between the two cases. The reactions mediated by CoIICbx were observed to be endothermic and possess higher activation energies in contrast to the reactions where the CoICbx complex is present. The latter was supported by the reaction force results, which suggest a relationship between the activation energy and the ionization potentials of the different nucleophiles present in the cleavage reaction. Moreover, the SF results indicates that the lower axial ligand (i.e., 5,6-dimethylbenzimidazole) exclusively participates on the first stage of the reaction mediated by the CoIICbx complex, while for the CoICbx case, it appears to have an important role along the whole process. Finally, the QTAIM charge analysis indicates that oxidation of the cobalt atom occurs in both cases; at the same time, it suggests the formation of an uncommon two-center one-electron bond in the CoIICbx case. The latter was confirmed by means of electron localization calculations, which resulted in a larger electron count at the Co-C interatomic region for the CoICbx case upon comparison with its CoIICbx counterpart.

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The nature of the Na⋯B bond, in the recently synthesized NaBH 3 - adduct, is analyzed on the light of the Na- propensity to polarize along the bond axis as a consequence of the electric field produced by the BH3 fragment. The observed induced polarization has two consequences: (i) the energetic stabilization of the Na- , and (ii) the split of its valence electrons into two opposite lobes along the bond axis. Additionally, an analysis of the electron localization is presented using the information content of the correlated conditional pair density that reveals a significant delocalization between one lobe of the polarized Na- anion and the BH3 fragment at the equilibrium distance. Our findings reported here complement previous works on this system.

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In the present work, the fast amide bond cleavage of [3-((1R,5S,7s)-3-azabicyclo[3.3.1]nonane-7-carbonyl)-3-azabicyclo[3.3.1]nonane-7-carboxylic acid (bi-ATDO)], through an intramolecular nucleophilic attack of an amine group is evaluated. First, six possible peptide bond cleavage mechanisms, two of them including a water molecule, are described at the ωB97XD/6-311 + G(d,p)//MP2/6-311 + G(d,p) level of theory. The reaction consisting of an intramolecular nitrogen nucleophilic attack followed by a proton transfer and the amide bond cleavage is determined as the most favorable mechanism. The activation free energy computed for the latter is 20.5 kcal mol-1 , which agrees with the reported experimental result of 24.8 kcal mol-1 . Inclusion of a water molecule to assist the first step of the reaction results in an activation free energy increase of about 17 kcal mol-1 . All the steps in the most favorable mechanism are studied more in detail employing intrinsic reaction coordinate as well as the reaction force and reaction electronic flux analysis.

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In the present work, a number of R-X⋯NH3 (X = Cl, Br, and I) halogen bonded systems were theoretical studied by means of DFT calculations performed at the ωB97XD/6-31+G(d,p) level of theory in order to get insights on the effect of the electron-donating or electron-withdrawing character of the different R substituent groups (R = halogen, methyl, partially fluorinated methyl, perfluoro-methyl, ethyl, vinyl, and acetyl) on the stability of the halogen bond. The results indicate that the relative stability of the halogen bond follows the Cl < Br < I trend considering the same R substituent whereas the more electron-withdrawing character of the R substituent the more stable the halogen bond. Refinement of the latter results, performed at the MP2/6-31+G(d,p) level showed that the DFT and the MP2 binding energies correlate remarkably well, suggesting that the Grimme's type dispersion-corrected functional produces reasonable structural and energetic features of halogen bond systems. DFT results were also observed to agree with more refined calculations performed at the CCSD(T) level. In a further stage, a more thorough analysis of the R-Br⋯NH3 complexes was performed by means of a novel electron localization/delocalization tool, defined in terms of an Information Theory, IT, based quantity obtained from the conditional pair density. For the latter, our in-house developed C++/CUDA program, called KLD (acronym of Kullback-Leibler divergence), was employed. KLD results mapped onto the one-electron density plotted at a 0.04 a.u. isovalue, showed that (i) as expected, the localized electron depletion of the Br sigma-hole is largely affected by the electron-withdrawing character of the R substituent group and (ii) the R-X bond is significantly polarized due to the presence of the NH3 molecule in the complexes. The afore-mentioned constitutes a clear indication of the dominant character of electrostatics on the stabilization of halogen bonds in agreement with a number of studies reported in the main literature. Finally, the cooperative effects on the [Br-CN]n system (n = 1-8) was evaluated at the MP2/6-31+G(d,p) level, where it was observed that an increase of about ~14.2% on the complex stability is obtained when going from n = 2 to n = 8. The latter results were corroborated by the analysis of the changes on the Fermi-hole localization pattern on the halogen bond zones, which suggests an also important contribution of the electron correlation in the stabilization of these systems.

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RESUMEN Las manifestaciones clínicas de las malformaciones vasculares intracraneanas en niños incluyen las derivadas de sangrados, así como las hemodinámicas que dependen del tamaño de la malformación. Algunas pueden consumir un alto porcentaje del gasto cardiaco, y llevar a falla cardiaca o a hipertensión pulmonar derivada del hiperflujo. Se presenta el caso de un lactante con hipertensión pulmonar y falla cardiaca que fue diagnosticada tardíamente, aunque con corrección endovascular dentro de la edad recomendada y buen desenlace neurológico. Se enfatiza en la necesidad de considerar las malformaciones vasculares intracraneales dentro del diagnóstico diferencial de niños con hipertensión pulmonar que no responden al tratamiento.

SUMMARY Clinical manifestations of intracranial vascular malformations in children include those derived from bleeding, as well as hemodynamic problems due to the size of some large malformations These may consume a high percentage of cardiac output, leading to heart failure, or pulmonary hypertension. We present the case of an infant with pulmonary hypertension and heart failure who was diagnosed late, but with endovascular correction within the recommended age, and had good neurological outcome. Emphasis is placed on the need to consider intracranial vascular malformations within the differential diagnosis of children with pulmonary hypertension who do not respond to treatment.

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RESUMEN Se han desarrollado estudios relacionados con la influencia de la diabetes mellitus en el sistema estomatognático de manera general y en particular en la salud periodontal, sin embargo es un campo insuficientemente abordado, principal motivación para la realización de esta investigación epidemiológica del tipo analítica de caso y control, la que tuvo como objetivo determinar el efecto de la diabetes mellitus tipo I y II en la salud periodontal, de pacientes con 30 a 60 años, del Consultorio Médico de la Familia No. 39, en el Reparto Rosa La Bayamesa, de Bayamo. El universo fue de 631 personas y la muestra de 168, distribuidas en grupos casos y controles. Las principales variables estudiadas fueron: tipo de diabetes mellitus, grupos de edades, sexo, enfermedad periodontal inflamatoria crónica y su severidad. Predominaron como resultados que, la morbilidad de la diabetes mellitus (DM) aumentó con la edad 75,00%, predominando está en el sexo femenino 62,50%.Se observó que la enfermedad periodontal inflamatoria crónica presentó una frecuencia total 88,10%; para un (OR) de 5,17 y p=0,0164; los más afectados fueron aquellos que padecían (DM), 96,43%. En los pacientes con diabetes mellitus, presentó mayor severidad la periodontitis78,57%, mientras que en los controles predominó la gingivitis 64,29%, se cuantificó un (OR) de 2,00.

ABSTRACT Studies have been developed related to the influence of diabetes mellitus in the stomatognathic system in a general way and in particular in periodontal health, however it is an insufficiently addressed field, the main motivation for carrying out this epidemiological investigation of the analytical type of case and control, which aimed to determine the effect of type I and II diabetes mellitus on the periodontal health of patients aged 30 to 60 years, from the Family Medical Office No. 39, in the Rosa La Bayamesa Division, of Bayamo . The universe was of 631 people and the sample of 168, distributed in case and control groups. The main variables studied were: type of diabetes mellitus, age groups, sex, chronic inflammatory periodontal disease and its severity. Predominated as results that the morbidity of diabetes mellitus (DM) increased with age 75.00%, predominantly in the female sex 62.50%. It was observed that chronic inflammatory periodontal disease presented a total frequency 88.10% ; for an (OR) of 5.17 and p = 0.0164; The most affected were those who suffered (DM), 96.43%. In patients with diabetes mellitus, periodontitis was more severe, 78.57%, while in controls, 64.29% had gingivitis, and a (OR) of 2.00 was quantified.

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Introducción: la cardiopatía isquémica es un problema de salud que cobra un gran número de vidas y es causa de invalidez en la población mundial. Constituyó en el 2013, la primera causa de muerte en el mundo, en Cuba y en la provincia de Matanzas. Objetivo: cuantificar la presencia de factores de riesgo de cardiopatía isquémica en el AIM del Policlínico Docente Cesáreo Sánchez, en Pedro Betancourt entre los meses de diciembre 2013 a Mayo del 2014. Materiales y Métodos: se realizó un estudio observacional, descriptivo, transversal de 59 pacientes que ingresaron con este diagnóstico entre los meses de diciembre 2013 a Mayo 2014. Se recogieron variables como la edad, sexo, factores de riesgo, formas clínicas de presentación, complicaciones presentadas durante el ingreso y presencia del síndrome metabólico. Resultado: hubo un predominio del sexo masculino y del grupo de edad de 65 y más. La hipertensión arterial y el sedentarismo fueron los factores de riesgo más sobresalientes, así como la angina estable y las arritmias cardíacas como la forma clínica y complicación más frecuente respectivamente. La presencia del síndrome metabólico caracterizó a los pacientes estudiados. Conclusiones: la detección y control oportuno de los factores de riesgo de la cardiopatía isquémica continuara siendo la piedra angular de cualquier estrategia preventiva esencial (AU).

Introduction: the ischemic cardiopathy or ischemic cardiovascular disease is a health problem claiming a great number of lives, being a cause of disability in the world population. In 2013 it was the first cause of death worldwide, in Cuba and in the province of Matanzas. Objective: to quantify the presence of the ischemic cardiopathy risk factors in the municipal intensive area (AIM as abbreviation in Spanish) of the Teaching Policlinic Cesareo Sanchez, in Pedro Betancourt, from December 2013 to May 2014. Materials and methods: a cross-sectional, descriptive, observational study was carried out in 59 patients who entered the area with this diagnosis from December 2013 to May 2014. The collected variables were age, sex, risk factors, clinical forms of presentation, complications during staying, and presence of the metabolic syndrome. Results: the results showed the predominance of the male sex and the age group of 65 years and more. Arterial hypertension and sedentary lifestyle were the most outstanding risk factors, and the stable angina and heart arrhythmias were the most frequent clinical form and complication, respectively. The presence of metabolic syndrome characterized the studied patients. Conclusions: the timely detection and control of the ischemic cardiopathy risk factors is still going to be the cornerstone of any essential preventive strategy (AU).

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La neurocisticercosis es una enfermedad con alta prevalencia en países tropicales y de bajos recursos, sin embargo su incidencia ha aumentado en países desarrollados. Este es el caso de una mujer de 49 años con neurocisticercosis subaracnoidea generalizada asociada a compromiso encefálico y medular, una presentación rara de este parásito neurotrópico,con convulsiones y limitación motora severa. Las imágenes muestran respuesta inflamatoria generalizada del cerebro y el espacio subaracnoideo, hidrocefalia y múltiples lesiones calcificadas, reafirmando la importancia de las neuroimágenes para la correlación clínica y el diagnóstico de las enfermedades infecciosas cerebrales como la neurocisticercosis, con variabilidad en la presentación y múltiples compromisos del sistema nervioso central.

Neurocysticercosis is a disease of high prevalence in tropical and low-income countries and its incidence has been increased in developed countries. This is the case of 49-year-old woman with generalized subarachnoid neurocysticercosis associated to encephalic and medullar compromise, a rare presentation of this neurotropic parasite, with seizures and severe motor limitation. Images showed generalized inflammatory response of the brain and spinal subarachnoid space, hydrocephalus and multiple calcified lesions, demonstrating and reaffirming the importance of neuroimaging tools for the clinical correlation and diagnosis of brain infectious diseases as neurocysticercosis with variability on the presentation and multiple central nervous system involvement.

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