Packing core-corona particles on a spherical surface.

We explore the non-trivial structures that can be obtained by the assembly of repulsive core-corona particles confined on a spherical surface. Using Monte Carlo simulations, we study the low-temperature equilibrium configurations as a function of the size of the confining (spherical) surface for a small number of particles (N ≤ 12) and obtain a large variety of minimal-energy arrangements including anisotropic and chiral structures. For a small cluster (N = 4), we construct a phase diagram in the confining surface radius vs corona range plane that showed regions where configurations with a certain energy are not accessible. Also, a phase diagram in the temperature and confining surface radius plane showed the presence of reentrant phases. The assembly of Platonic and Archimedean solids and the emergence of helical structures are also discussed. When the number of particles is large (N ≥ 100), apart from the appearance of defects, the overall configurations correspond closely to the ones formed in an unconfined two-dimensional case. Interestingly, the present model reproduces the symmetry of experimentally obtained small clusters of colloidal spheres confined at the surface of evaporating liquid droplets which cannot be explained in terms of packing of hard spheres. Thus, our simulations provide insight on the role that the softness of the particles may have in the assembly of clusters of nanoparticles.

The advertisement call of the Colombian endemic glassfrog Rulyrana susatamai (Anura: Centrolenidae).

Anuran calls are conspicuous, diverse and subject to sexual selection. Many types of calls are described, but the most commonly studied is the advertisement call (Wells 2007; Toledo et al. 2014). Advertisement calls in anurans are emitted by males and some females (Toledo et al. 2014), and have the function of attracting conspecific mates and repelling male competitors. Because the advertisement calls of many species differ by such a magnitude that they serve as premating species (Heyer et al. 1996), it has been demonstrated that advertisement calls play an important role in species recognition, reproductive isolation, and may reflect evolutionary relations among taxa (Wells 2007; Escalona et al. 2018).

Infarto medular en paciente con aneurisma de aorta descendente con hematoma intramural / Medular Infarction in Patient with Descending Aorta Aneurysm with Intramural Hematoma

La isquemia medular (IM) es una emergencia médica causada por hipoperfusión o embolismo de la arteria espinal. El inicio de los síntomas es abrupto, y su presentación clínica y gravedad es amplia, dependiendo del segmento medular comprometido. Entre las causas más frecuentes están la enfermedad ateroesclerótica, las cirugías vasculares aórticas y, menos comúnmente, la disección aórtica (DA). La IM conlleva secuelas graves y alta mortalidad. Este artículo describe el caso de un paciente con infarto medular agudo como primera manifestación de un hematoma intramural (HIM) en un aneurisma de aorta torácica.

Spinal cord ischemia is a medical emergency due to hypoperfusion or embolization of the spinal artery. The onset of symptoms is abrupt and the clinical presentation depends on the medullary territory involved. The most frequent causes are atherosclerotic disease, aortic surgery and less commonly, aortic dissection, which is associated with serious complications and greatest risk of mortality. This article describes the case of a patient with an acute spinal infarction as the first manifestation of an intramural hematoma in a thoracic aortic aneurysm.

The advertisement call of Centrolene notostictum (Anura, Centrolenidae) with a new record of geographic distribution in Tolima, Colombia.

Centrolene notostictum Ruiz-Carranza Lynch,1991 is a glassfrog known from the Cordillera Oriental of Colombia-in the Departments of Boyacá, Cundinamarca, Norte de Santander and Santander (Frost 2017)-and the Venezuelan versant of the Sierra de Perijá (Rojas et al. 2012) from 1600 to 2440 masl. Although males have been found calling on the upper surface of the leaves of ferns and Heliconeaceae on the margins of a small fast-flowing stream (Rojas et al. 2012), no quantitative description of the advertisement call of C. notostictum is currently available. During fieldwork in the Galilea Natural Forest (on the western slope of Cordillera Oriental in the municipality of Villarrica, department of Tolima, Colombia) in 2016 and 2017, we found three vocalizing males of C. notostictum. Herein, we report the first geographic record of this species for the department of Tolima and describe its previously unknown advertisement call.

Rediscovery of Atelopus subornatus Werner, 1899 (Anura: Bufonidae), with a redescription of the tadpole.

The Neotropical toads of the genus Atelopus are among the most imperiled of all amphibians (La Marca et al. 2005; Gonzalez-Maya et al. 2013; McCaffery et al. 2015). Nowadays, at least 90% of the 93 listed species are threatened and more than 77% are Critically Endangered (McCaffery et al. 2015; IUCN 2016). Colombia has 44 described species of Atelopus (Frost 2017), two of these are categorized as extinct (EX) by the IUCN (2016): A. ignescens and A. longirostris, although they were recently re-discovered in Ecuador (Tapia et al. 2017), 34 as critical endangered (CR), four as endangered (EN), two as vulnerable (VU), one species has data deficient (DD) and another one has not been evaluated. Atelopus subornatus Werner, 1899, is an endemic Colombian harlequin toad described from 2300 to 2800 m.a.s.l in the municipalities of Sibaté (Alto de Sibaté and Agua Bonita) and Fusagasuga (above Fusagasuga and Tierra Negra), in Cundinamarca (Fig. 1A), on the western flank from Cordillera Oriental of Colombia (Werner 1899; Lynch 1986; Lötters 1989, 1992). The last record of this species was in 1993 (Lötters 2005), and it currently is listed as Critically Endangered by the IUCN (2016). Herein, we report the rediscovery of A. subornatus at a new locality from Tolima, Colombia (Fig. 1A), and redescribe its tadpole. The determination of the species was based on comparisons with material deposited in the amphibian collection of the Instituto de Ciencias Naturales, Universidad Nacional de Colombia (ICN-UNAL) for all species of Atelopus reported from the same general area in Cundinamarca and relatively similar to A. subornatus. The specimens are housed in the Herpetological collection of the Tolima University (CZUT-A) and amphibian collection of ICN-UNAL.

Electrical stimulation of the inferior thalamic peduncle in the treatment of major depression and obsessive compulsive disorders.

OBJECTIVE: Stimulation of the inferior thalamic peduncle (ITP) is emerging as a promising new therapeutic target in certain psychiatric disorders. The circuitry that includes the nonspecific thalamic system (NSTS), which projects via the ITP to the orbitofrontal cortex (OFC), is involved in the physiopathology of major depression disorder (MDD) and obsessive compulsive disorder (OCD). The safety and efficacy of chronic ITP stimulation in cases of MDD and OCD refractory to medical treatment is presented. MATERIALS AND METHODS: Six patients with OCD and one with MDD were implanted with tetrapolar deep brain stimulation electrodes in the ITP (x = 3.5 mm lateral to the ventricular wall, y = 5 mm behind the anterior commissure, and z = at the intercommissural plane, i.e., anterior commissure-posterior commissure [AC-PC] level). The effect of chronic stimulation at 130 Hz, 450 µs, and 5.0 V on OCD was evaluated before and 3, 6, and 12 months after initiation of electrical stimulation through the Yale-Brown Obsessive Compulsive Scale, Hamilton Depression Rating Scale, and Global Assessment of Function scale. RESULTS: Chronic ITP electrical stimulation in OCD patients decreased the mean Yale-Brown Obsessive Compulsive Scale score to around 51% for the group at the 12-month follow-up, and increased the mean Global Assessment of Function scale score to 68% for a significant improvement (P = 0.026). Three of 6 patients returned to work. The Hamilton Depression Rating Scale score of the only patient with MDD treated to date went from 42 to 6. This condition of the patient, who had been incapacitated for 5 years prior to surgery, has not relapsed for 9 years. Three OCD patients with drug addiction continued to consume drugs in spite of their improvement in OCD. CONCLUSION: Deep brain stimulation in the ITP is safe and may be effective in the treatment of OCD. A multicenter evaluation of the safety and efficacy of ITP in OCD is currently in process.

Epilepsia en mayor de 60 años en un centro neurològico de referencia en la ciudad de Cali, Colombia / Epilepsy in over 60 years in a neurological center of reference in the city of Cali, Colombia

INTRODUCCIÓN: a partir de los 50 años la incidencia de crisis epilépticas de novo aumenta con cada década, en pacientes mayores de 60 años, a la prevalencia que se sitúa alrededor del 1.2%. Este grupo etario constituye el 6.5% de la población colombiana, lo cual nos permite calcular que en el país alrededor de 35.000 personas en este rango de edad tendrían epilepsia, muchas veces subdiagnósticados porque la forma de presentación clínica usual es diferente a otros grupos etarios. OBJETIVO: describir las características sociodemográficas, clínicas y paraclínicas de la población mayor de 60 años con crisis epilépticas de novo en un centro neurológico de referencia en la ciudad de Cali. MATERIALES Y MÉTODOS: estudio descriptivo retrospectivo. Análisis de variables por medio de frecuencias, promedios y proporciones. RESULTADOS: muestra 51 pacientes. Edad promedio: 73 años. El 47,1% tuvo antecedente de hipertensión arterial, el 37.3% de uno o múltiples ataques cerebrovasculars bien sea como un evento claramente definido por clínica e imágenes o sólo con evidencia de lesiones cerebrales microangiopáticas. Las crisis fueron focales en el 60,7% de pacientes, de los cuales el 76,4% recibieron tratamiento farmacológico con ácido valpróico como monoterapia y de ellos el 90,2% se halla controlado. CONCLUSIÓN: en la población mayor de 60 años la epilepsia se presenta habitualmente con una semiología de crisis diferentes a la de otros grupos etarios, lo cual debe tenerse en cuenta al momento de la consulta para poder identificarlos a través de una detallada historia clínica. Se halló que el ácido valpróico a dosis bajas fue un medicamento eficaz y seguro en esta población donde la etiología más frecuente es la enfermedad cerebro vascular (ECV).

INTRODUCTION: after the age of 50 the incidence of the novo seizures increases with each decade, leading to a prevalence of around 1.2% in patients over 60 years. This age group is 6.5% of the Colombian population, which allows us to calculate that in the country about 35,000 people in this age range have epilepsy, often underdiagnosed because the usual clinical presentation is different from other age groups. OBJECTIVE: to describe the sociodemographic, clinical and paraclinical characteristics of the population over 60 years with the novo seizures in a neurological center of reference in the city of Cali. MATERIALS AND METHODS: a descriptive retrospective study. Analysis of variables using frequencies, means and proportions. RESULTS: sample 51 patients. Average age: 73 years. 47.1% had a history of hypertension, 37.3% had one or multiple cerebrovascular attacks ,events either as a clearly defined clinical picture, or just evidence of microangiopathic brain lesions. Seizures were focal in 60.7% of the patients, of whom 76.4% received pharmacological treatment with valproic acid as monotherapy and 90.2% of them is controlled. CONCLUSION: in the population over 60 years, epilepsy occurs usually with a semiology of crisis different to that of other age groups, which should be taken into account during the medical consultation in order to identify them through a detailed medical history. It was found that low-dose valproic acid was an effective and safe drug in this population where the most common cause is cerebrovascular disease (CVD).

Microinjection of GABAergic agents into the anterior nucleus of the thalamus modulates pilocarpine-induced seizures and status epilepticus.

The anterior nucleus of the thalamus (AN) has been suggested as a potential target for seizure modulation in animal models and patients with refractory epilepsy. We investigate whether microinjections of GABAergic agonists into the AN were protective against pilocarpine-induced generalized seizures and status epilepticus (SE). Rats were treated with bilateral AN injections of muscimol (160 or 80 nmol), bicuculline (15 nmol), or saline (controls) 20 min prior to pilocarpine administration (350 mg/kg i.p.). Electrographic recordings were used to confirm seizure activity. We found that pretreatment with AN muscimol 160 nmol increased the latency to seizures and SE by 2.5-3.0-fold. This dose however was associated with side effects, particularly hypotonia. AN bicuculline was proconvulsant, whereas no major effect was observed after muscimol 80 nmol injections. The percentage of animals that developed SE was similar across groups. Overall, microinjection of high doses of muscimol into the AN delayed the occurrence of pilocarpine-induced seizures and SE but was not able to prevent these events.

Bilateral anterior thalamic nucleus lesions are not protective against seizures in chronic pilocarpine epileptic rats.

AIMS: To investigate whether anterior thalamic nucleus (AN) lesions are protective against spontaneous recurrent seizures in the chronic phase of the pilocarpine model of epilepsy. METHODS: Two groups of rats were treated with bilateral AN radiofrequency thalamotomies or sham surgery 2 weeks after pilocarpine-induced status epilepticus. After the lesions, animals were videotaped from the 2nd to the 8th week after status epilepticus (total 180 h). RESULTS: During the 6 weeks of observation, no differences in the frequency of spontaneous seizures were found between animals that had bilateral AN lesions (n = 26; 3.1 +/- 0.6 seizures per animal) and controls (n = 25; 3.0 +/- 0.6 seizures per animal; p = 0.8). CONCLUSIONS: We conclude that AN thalamotomies were not effective in reducing the frequency of seizures during the chronic phase of the pilocarpine model of epilepsy.

Situación actual de las plantaciones forestales ejecutadas por el proyecto piloto de ecosistemas andinos, en la subcuenca del Río Manzanas / Current situation of the forest plantations executed by the pilot scheme of Andean Ecosystems, in the Subbasin of the Rio Apples

Se evaluó la supervivencia de las plantaciones forestales ejecutadas por el Proyecto Piloto de Ecosistemas andinos (PPEA), desarrolladas en la subcuenca del río manzanas, en las cercanías de la ciudad de Cajamarca, determinándose además las especies forestales de mayor aceptación por la comunidad, las cuales servirán de base para continuar con un probable programa de reforestación. La evaluación de supervivencia se realizó mediante párcelas de muestreo en las que se consideró el 100 por ciento de los individuos. Se determinó que las plantaciones en macizo, tienen una sobrevivencia del 34 por ciento. Los bosquetes cuentan con un promedio de 450 plantas por ha, con un diámetro a la altura del pecho de 11.7 cm y un volumen de 33.38 m3/ha. Los pobladores manifestaron su deseo de continuar plantando especies forestales, prefiriendo en un 95 por ciento al eucalipto (Eucalyptus globulus), seguido del aliso (Alnus acuminata) con 3 por ciento y el pino (Pinus sp.) con 2 por ciento, sin embargo expresaron su expectativa de obsequio de plantones y remuneración por los trabajos a ejecutar.