Improving Extracorporeal Membrane Oxygenation Survival in COVID-19. Effect of a Bundle of Care.

Veno-venous extracorporeal membrane oxygenation (ECMO) support surged during the COVID-19 pandemic. Our program changed the model of care pursuing to protect the multidisciplinary team from the risk of infection and to serve as many patients as possible. Patient-healthcare interactions were restricted, and the ECMO bed capacity was increased by reducing the ECMO specialist-patient ratio to 1:4 with non-ECMO trained nurses support. The outcomes worsened and we paused while we evaluated and modified our model of care. The ECMO bed capacity was reduced to allow a nurse ECMO-specialist nurse ratio 2:1 with an ECMO trained nurse assistant's support. Intensivists, general practitioners, nurse assistants, and physical and respiratory therapists were trained on ECMO. Tracheostomy, bronchoscopy, and microbiological molecular diagnosis were done earlier, and family visits and rehabilitation were allowed in the first 48 hours of ECMO cannulation. There were 35 patients in the preintervention cohort and 66 in the postintervention cohort. Ninety days mortality was significantly lower after the intervention (62.9% vs. 31.8%, p = 0.003). Factors associated with increased risk of death were the need for cannulation or conversion to veno arterial or veno arterio venous ECMO, hemorrhagic stroke, and renal replacement therapy during ECMO. The interventions associated with a decrease in the risk of death were the following: early fiberoptic bronchoscopy and microbiological molecular diagnostic tests. Increasing the ECMO multidisciplinary team in relation to the number of patients and the earlier performance of diagnostic and therapeutic interventions, such as tracheostomy, fiberoptic bronchoscopy, molecular microbiological diagnosis of pneumonia, rehabilitation, and family support significantly decreased mortality of patients on ECMO due to COVID-19.

Anticancer and antileishmanial in vitro activity of gold(I) complexes with 1,3,4-oxadiazole-2(3H)-thione ligands derived from δ-D-gluconolactone.

Four gold(I) complexes conceived as anticancer agents were synthesized by reacting [Au(PEt3 )Cl] and [Au(PPh3 )Cl] with ligands derived from δ-d-gluconolactone. The ligands' structure was designed to combine desired biological properties previously reported for each group. Ligands were synthesized from δ-d-gluconolactone via ketal protection and hydrazide formation followed by cyclization with CS2 to produce the novel oxadiazolidine-2-thione 7 and 8. Increasing of the ligands' lipophilicity via ketal protection proved useful since all four gold(I) complexes showed anticancer and antileishmanial properties. The IC50 values are at low micromolar range, varying from 2 to 3 µm for the most active compounds. The free D-gluconate 1,3,4 oxadiazole-derived ligands were neither toxic nor presented anticancer or antileishmanial properties. Triethylphosphine-derived compounds 9 and 10 were more selective against B16-F10 melanoma cell line. Although similar in vitro antileishmanial activity was observed for the gold(I) precursors themselves and their derived complexes, the latter were three times less toxic for human THP-1 macrophage cell line; this result is attributed to an isomeric variation of the D-gluconate ligand and the oxadiazole portion, which was one of the key concepts behind this work. These findings should encourage further research on gold(I) complexes to develop novel compounds with potential application in cancer and leishmaniasis chemotherapy.

Retinopatía esclopetaria: reporte de caso y revisión de literatura / Retinitis sclopetaria: Case report and literature review

Introducción: La retinopatía esclopetaria se presenta en casos de trauma ocular cerrado por proyectiles de alta velocidad a nivel orbitario y periorbitario con alteraciones secundarias en la coroides, retina, epitelio pigmentario de la retina y membrana de Bruch. Por la rara ocurrencia de este mecanismo de trauma, es una complicación poco frecuente del trauma ocular cerrado que se presenta en el momento inicial del trauma y genera secuelas a largo plazo. Objetivo: Dar a conocer las características clínicas y las secuelas de la retinopatía esclopetaria. Diseño del estudio: Observacional. Material y métodos: Se presenta el caso clínico de un hombre de 45 años con antecedente de herida por arma de fuego hace 27 años, con restos de esquirlas metálicas a nivel frontal, con disminución de agudeza visual crónica, hallazgos de catarata subcapsular posterior y a la fundoscopia cicatriz coriorretinal compatible con retinopatía esclopetaria. Se indica manejo médico con observación de la alteración del segmento posterior y manejo quirúrgico de la catarata secundaria al trauma. Conclusiones: La retinopatía esclopetaria puede generar daños agudos y secuelas que conlleven disminución de la agudeza visual; el manejo es médico observacional. Según la localización de los hallazgos se definirán las secuelas visuales. El diagnóstico oportuno y seguimiento son el pilar del tratamiento.

Background: Retinitis sclopetaria occurs in cases of closed ocular trauma caused by high-speed bullets at the orbital and periorbital tissues with secondary alterations in the choroid, retina, RPE and Bruch's membrane. Due to the rare occurrence of this mechanism, it is a rare complication of closed ocular trauma that occurs at the initial moment of trauma and generates long-term sequelae. Objective: To present clinical characteristics and the sequelae of a case of retinitis sclopetaria. Study design: Observational Material and methods: We present the clinical case of a 45-year-old man with a history of firearm injury 27 years ago, with remains of metallic splinters at the frontal level, with decreased chronic visual acuity, findings of a posterior subcapsular cataract and fundoscopy of chorioretinal scar compatible with retinitis sclopetaria. Medical management was indicated with observation and surgical management of the cataract secondary to trauma. Conclusions: Retinitis sclopetaria can cause acute damage and sequelae that lead to decreased visual acuity; treatment is observation. Visual sequelae is defined depending on the location of the retinal alterations. Diagnosis and follow-up are the mainstay of managemen

Changes in the mechanical properties of two nickel-titanium archwires after 3 months of clinical usage.

BACKGROUND: Nickel-titanium archwires have unique mechanical properties that make them the archwire of choice during the first phase of orthodontic treatment. However, during its clinical use when subjected to oral conditions, these properties can undergo great changes. MATERIALS AND METHODS: A sample of 24 randomly chosen superelastic NiTi orthodontic archwires (12 TE and 12 PSE) with a 0.014-inch round section from the same manufacturer were distributed into four groups of six archwires each. The first two groups were new wires (as-received), which were used as controls (T0), and the other two were collected after 3 months of clinical usage (as-retrieved) in orthodontic patients (T1). Mechanical properties were measured by mechanical tensile testing and three-point bending tests under the same experimental and temperature conditions (36°C) in a universal testing machine. Comparisons between the groups at T0 and T1 were performed with t-tests and Mann-Whitney U tests. A paired t-test and Wilcoxon signed rank sum test were used for intragroup comparisons (T1-T0). RESULTS: At baseline, PSE wires presented significantly (P < 0.05) higher load at fracture, range, ultimate tensile strength (UTS), yield strength, springback, maximum tension and flexural ultimate strength (FUS) than those of TE wires. At T1, a significant decrease in load at fracture and UTS in PSE wires and in FUS in TE wires was found. After 3 months of clinical usage, the changes (T1-T0) in the mechanical properties of both alloys were similar. CONCLUSIONS: After 3 months of clinical usage, wires lost some of their mechanical properties and had less resistance to breakage. However, the as-received differences between both wires were maintained after clinical usage.

Neurorretinitis por Bartonella henselae. Reporte de caso y revisión de la literatura / Bartonella henselae neuroretinitis. A case report and literature review

Introducción: La Enfermedad por Arañazo de Gato (EAG) es una enfermedad zoonótica causada por Bartonella henselae, un bacilo gram negativopleomórfi co. Sus manifestaciones clínicas varían de acuerdo a la respuesta inmunológica instaurada por el huésped, pudiendo ser de tipo granulomatosa o angioproliferativa. El diagnóstico es clínico, sin embargo, se utiliza la serología e imágenes multimodales para la confi rmación diagnóstica y el seguimiento de la misma. Objetivo: Describir el caso de una paciente joven que presenta aftasorales recurrentes como única manifestación sistémica de EAG asociado a neurorretinitis unilateral, quien es manejada con antibiótico en combinación con corticoide sistémico. Diseño del estudio: Reporte de caso Resumen del caso: Paciente con antecedente de contacto directo con gatoscachorros y aft as orales recurrentes; presenta disminución de la agudeza visual en ojo izquierdo. Al examen oft almológico presenta papilitis, hemorragias intrarretinianas y presencia de cicatriz coriorretiniana en ojo contralateral. Ante los hallazgos descritos se indica manejo antibiótico por sospecha de infección por toxoplasmosis, sin embargo, presenta evolución tórpida. Se realizan estudios complementarios que evidencian desprendimiento seroso de retina con evolución a estrella macular, por lo que se modifi ca el esquema antibiótico a los 15 días, presentando mejoría de la sintomatología. Conclusión: La neurorretinitis secundaria a enfermedad por arañazo de gato es una entidad subdiagnosticada en nuestro medio, lo que hace importante indagar sobre antecedentes de contacto con felinos y los posibles diagnósticos diferenciales. Es esencial establecer esquemas de manejo antibiótico basados en la literatura ante la sospecha de la enfermedad para evitar sus posibles complicaciones.

Background: Cat Scratch Disease is a zoonotic disease caused by Bartonella henselae, a pleomorphic gram negative bacillus. Its clinical manifestations vary according to the immune response established by the host, it may be a granulomatous or angioproliferative type. Th e diagnosis is based on clinical fi ndings, however, serology and multimodal images are used for diagnosis confi rmation and monitoring. Objective: To describe the case of a young patient, who presents recurrent oral thrush as the only systemic manifestation of CSD associated with unilateral neuroretinitis, who is managed with antibiotic in combination with systemic corticosteroid. Study Design: Case report. Case summary: Patient with a history of direct contact with puppy cats and recurrent oral thrush; presents decreased visual acuity in the left eye. During ophthalmological examination, she presents papillitis, intraretinal hemorrhages and the presence of a chorioretinal scar in the contralateral eye. Given the fi ndings described, antibiotic management is indicated due to suspected toxoplasmosis infection, however, she presents a torpid evolution. Th e complementary tests show serous retinal detachment with evolution to macular star, thus treatment regimen is modifi ed aft er 15 days with secondary symptoms improvement. Conclusion: Neuroretinitis secondary to cat scratch disease is an underdiagnosed entity in our setting, which makes it important to inquire about feline contact history and possible diff erential diagnoses. It is essential to establish antibiotic management schemes based on the literature when the disease is suspected to avoid its possible complications

Cisticercosis ocular en un paciente procedente de la región de Orinoquía, Colombia. Reporte de caso / Ocular cysticercosis in a patient from Orinoquia, Colombia. A case report

Introducción: La cisticercosis ocular es una patología ocasionada principalmente por el parásito Taenia solium. La infección ocurre posterior al consumo de carne mal cocida, agua contaminada o por autoinfección. Los principales órganos comprometidos son el sistema nervioso central (SNC), los ojos, el sistema músculo esquelético y el tejido celular subcutáneo. Objetivo: Describir la importancia del diagnóstico oportuno de la neurocisticercosis, sus hallazgos, evolución e implicaciones a nivel oft almológico Diseño de estudio: Reporte de caso y revisión de la literatura. Resumen de caso: Paciente de 29 años procedente de Orinoquía, Colombia con cuadro de 4 días de evolución de trauma ocular cerrado derecho con insecto volador mientras realizaba labores agrícolas. Presentó disminución de la agudeza visual, dolor ocular leve y ojo rojo. Al examen oft almológico se evidencia percepción y proyección de la luz y colores en ojo derecho, hiperemia conjuntival leve, pupila hiporreactiva y presión intraocular (PIO) de 9 mmHg. A la fundoscopia del ojo comprometido se encuentra quiste con contenido blanquecino y la ecografía ocular reporta la presencia de cisticerco. Conclusión: La cisticercosis ocular es una patología infrecuente a nivel mundial, sin embargo tiene mayor prevalencia en zonas rurales por la exposición a factores de riesgo. La literatura colombiana muestra un défi cit en el registro de casos debido al pobre diagnóstico y reporte. Se destaca la importancia del diagnóstico y tratamiento temprano para evitar afectación ocular severa.

Background: Ocular cysticercosis is a pathology caused mainly by the Taenia sollium parasite. Th e infection occurs aft er the consumption of poorly cooked meat, contaminated water or by auto infection. Th e main aff ected organs are the central nervous system, the eye, the musculoskeletal system and the subcutaneous tissue. Objective: Describe the importance of timely diagnosis of neurocysticercosis, clinical fi ndings, evolution and ophthalmologic compromise. Study design: Case report and systematic review of the literature. Case presentation: 29 year old patient coming from Orinoquia, Colombia with a 4 day clinical course of right closed ocular trauma with fl ying insect while working on palm harvest. Th e patient presented decreased visual acuity, ocular pain and eye redness. In the ophthalmologic exam of the right eye fi ndings include perception and projection of light and color, hyperemic conjunctiva, hyporeactive pupil and intraocular pressure of 9 mmHg. At fundoscopy a cyst with whitish content and the ocular ultrasound reports the presence of cysticercus. Conclusion: Ocular cysticercosis is an infrequent pathology globally nevertheless it has higher prevalence in our media, especially in rural areas by the presence of risk factors. Colombian literature shows a defi cit in the report of cases due to poor diagnosis of the pathology. Early diagnosis and treatment is important to avoid severe visual impairment.

Síndrome primario de Sjogren con manifestación retiniana. Reporte de caso / Primary Sjogren syndrome with retinal manifestation. A case report

Introducción: El Síndrome de Sjogren primario (SSp) es una enfermedad autoinmune, crónica y progresiva, con manifestaciones extraglandulares que comprometen el sistema nervioso central (SNC) y el sistema nervioso periférico (SNP), las cuales pueden ser fácilmente confundidas con otras patologías Objetivo: Resaltar la importancia de identifi car y evaluar adecuadamente las manifestaciones neurológicas del Síndrome de Sjögren primario ya que pueden representar el desarrollo temprano de la enfermedad en algunos casos Diseño de estudio: Reporte de caso clínico y revisión sistemática de la literatura. Resumen de caso: Se trata de una paciente joven con pérdida súbita de agudeza visual de ojo derecho, sin compromiso sistémico ni antecedentes de importancia. A la fundoscopia se evidencia papilitis, presencia de líquido subretiniano y hemorragias intrarretinianas puntiformes. Se realiza angiografía con fl uoresceína la cual muestra áreas infl amatorias vasculares que comprometen nervio óptico y tomografía de coherencia óptica macular evidenciando desprendimiento seroso retiniano, se solicita perfi l infeccioso e infl amatorio los cuales se encuentran dentro de límites normales, estudio imagenológico sin alteraciones y panel autoinmune con clara positividad de ANAS y factor reumatoideo con acuaporina 4 negativa siendo estos hallazgos compatibles con cuadro de neuritis óptica de etiología autoinmune, dado que se confi rma diagnóstico de SSp mediante biopsia de glándula salival menor Conclusión: La neuritis óptica al estar relacionada a un proceso vascular infl amatorio de origen autoinmune, se puede pasar por alto como un indicador del desarrollo de la SSp, y su diagnóstico tardío puede ocasionar complicaciones ópticas de carácter permanente. Las manifestaciones neurológicas se presentan en un porcentaje de rango amplio (8.5 ­ 85%)

Background: Primary Sjögren's syndrome (SSP) is an autoimmune, chronic and progressive disease. It presents extraglandular manifestations that aff ect the CNS and PNS and can be easily confused as a product of other diseases Objective: To highlight the importance of identifying and evaluate appropriately neurological manifestations of primary Sjogren syndrome given that they can represent the early development of the disease Study design: Clinical case report and systematic review of the literature Case summary: Th is is a young patient with sudden loss of visual acuity in the right eye, without systemic compromise or a signifi cant history. Papillitis, the presence of subretinal fl uid and punctate intraretinal hemorrhages are evident at the fundoscopy. Fluorescein angiography was performed, which shows vascular infl ammatory areas that compromise the optic nerve and macular optical coherence tomography showing retinal serous detachment, an infectious and infl ammatory profi le were requested, which are within normal limits, an imaging study without alterations and an autoimmune panel with clear positivity of ANAS and rheumatoid factor with aquaporin 4 negative, these fi ndings being compatible with symptoms of optic neuritis of autoimmune etiology, the diagnosis of SSp is confi rmed by minor salivary gland biopsy Conclusion: Optic neuritis being related to an infl ammatory vascular process of autoimmune origin can be overlooked as an indicator of the development of SSp, and its late diagnosis can cause permanent optical complications. Neurological manifestations occur in a wide range percentage (8.5-85%)

Características clínicas y OCT-SA de pacientes con síndrome de tracción iridiana asociado a desprendimiento de retina regmatógeno. Reporte de tres casos / Clinical features and AS-OCT of patients with iris retraction syndrome following rhegmatogenous retinal detachment. Report of three cases

Introducción: se presenta una serie de 3 casos de síndrome de retracción iridiana (SRI) asociados a desprendimiento de retina regmatógeno (DRR) y desprendimiento coroideo. Objetivo: dar a conocer las características clínicas y tomográficas de tres pacientes con SRI asociado a desprendimiento de retina regmatógeno. Diseño del estudio: serie de casos. Resumen del caso: tres pacientes que presentaron DRR asociado a SRI. El tiempo de evolución promedio fue de 21 días (15-30 días), 2 de los 3 pacientes tuvieron resolución del SRI posterior al inicio de midriáticos y antes de ser intervenidos por el desprendimiento de retina, y 2 tuvieron presencia de proliferación vitreoretiniana (PVR) a pesar del corto tiempo de evolución. Adicionalmente estos 2 pacientes cursaron con desprendimientos coroideos. Todos los pacientes tuvieron un buen resultado estructural, AV menor o igual a 20/400, no redesprendimientos ni recurrencias de SRI durante el seguimiento. Conclusión: ante un paciente con SRI en el cual no sea posible valorar polo posterior, se debe tener en cuenta el diagnóstico de desprendimiento de retina regmatógeno. El SRI puede considerarse como un factor de mal pronóstico en pacientes con desprendimiento de retina regmatógeno.

Background: to report a 3 cases series of patients with iris retraction syndrome (IRS). Objective: introduce the clinical and tomographic features of tree patients with IRS following RRD. Study design: case series. Case summary: three patients presented IRS following RRD. They presented with an average evolution of 21 days (15 to 30 days), 2 patients had resolution of the IRS after mydriatics and before receiving surgical treatment for retinal detacthment, and 2 had vitreoretinal proliferation despite the short time. Besides, these 2 patients had choroidal detachments discovered in the operating room. All patients had good structural outcomes, visual acuity less or equal than 20/400, no re-detachment of the retina and no recurrence of IRS during follow up. Conclusion: the presence of a retinal detachment should be suspected in a patient with IRS in which it´s not possible to assess the posterior pole, and it should be considered a bad prognostic factor if present.

T-Lymphocyte Deficiency Exacerbates Behavioral Deficits in the 6-OHDA Unilateral Lesion Rat Model for Parkinson's Disease.

T-lymphocytes have been previously implicated in protecting dopaminergic neurons in the substantianigra from induced cell death. However, the role of T-cells in neurodegenerative models such as Parkinson's disease (PD) has not been fully elucidated. To examine the role of T-lymphocytes on motor behavior in the 6-hydroxydopamine (6-OHDA) unilateral striatal partial lesion PD rat model, we assessed progression of hemi-parkinsonian lesions in the substantia nigra, induced by 6-OHDA striatal injections, in athymic rats (RNU-/-, T-lymphocyte-deficient) as compared to RNU-/+ rats (phenotypically normal). Motor skills were determined by the cylinder and D-amphetamine sulfate-induced rotational behavioral tests. Cylinder behavioral test showed no significant difference between unilaterally lesioned RNU-/- and RNU-/+ rats. However both unilaterally lesioned RNU-/- and RNU-/+ rats favored the use of the limb ipsilateral to lesion. Additionally, amphetamine-induced rotational test revealed greater rotational asymmetry in RNU-/- rats compared to RNU-/+ rats at two- and six-week post-lesion. Quantitative immunohistochemistry confirmed loss of striatal TH-immunopositive fibers in RNU-/- and RNU-/+ rat, as well as blood-brain-barrier changes associated with PD that may influence passage of immune cells into the central nervous system in RNU-/- brains. Specifically, GFAP immunopositive cells were decreased, as were astrocytic end-feet (AQP4) contacting blood vessels (laminin) in the lesioned relative to contralateral striatum. Flow cytometric analysis in 6-OHDA lesioned RNU-/+rats revealed increased CD4+ and decreased CD8+ T cells specifically within lesioned brain. These results suggest that both major T cell subpopulations are significantly and reciprocally altered following 6-OHDA-lesioning, and that global T cell deficiency exacerbates motor behavioral defects in this rat model of PD.

Short-term effects of intravitreal bevacizumab for subfoveal choroidal neovascularization in pathologic myopia.

PURPOSE: To determine short-term effects of intravitreal bevacizumab for subfoveal choroidal neovascularization (CNV) in pathologic myopia. METHODS: In this prospective interventional case series, patients were treated with 2.5 mg of intravitreal bevacizumab and followed for 3 months. Best-corrected visual acuity (BCVA), optical coherence tomography (OCT), and fluorescein angiography (FA) were recorded. Indications for retreatment were active leaking CNV shown by FA and presence of subretinal fluid by OCT in combination with visual disturbances. RESULTS: Fourteen patients were included, with a mean age of 53.86 +/- 16.26 years (range 29-85). Mean spherical equivalent was -13.87 +/- 3.68 diopters (-7.25 to -20.50). Minimum follow-up was 3 months. There were no adverse events. The mean initial visual acuity was 20/200 improving to 20/100 at 2 weeks, 20/80 at 4 weeks, and 20/60 at 8 and 12 weeks (P=0.007; P=0.001; P=0.005; P=0.001, respectively). Initial foveal thickness improved from 385.43 microm +/- 125.83 microm to 257.64 +/- 76.6 microm and 194.54 +/- 54.35 microm after the first and third month, respectively (P=0.001). CONCLUSIONS: Initial treatment results of patients with CNV due to pathologic myopia did not reveal any short-term safety concerns. Intravitreal bevacizumab resulted in a significant decrease in foveal thickness and improvement in visual acuity. These favorable initial results support further larger and long-term studies.

Variabilidad de la medida del mediastino (pedículo vascular e índice cardiotorácico) en la radiografía de tórax con la posición y respiración / Variability in the extent of the mediastinum (cardiothoracic index and vascular pedicle) on chest radiograph with the position and breathing

Objetivo: cuantificar las medidas del mediastino, índice cardiotorácico y pedículo vascular en las radiografías tomadas con el paciente en decúbito supino y en espiración, comparadas con las tomadas en vertical y en inspiración, y así proponer una estandarización del proceso de evaluación del mediastino. Materiales y métodos: estudio prospectivo de correlación inter-observadores, realizado en el servicio de imágenes diagnósticas del Hospital de San José, en el período comprendido entre enero y diciembre de 2.003. A los pacientes seleccionados dentro de los criterios de inclusión, se les realizaron cuatro radiografías en vertical y en decúbito, en inspiración y espiración, y se determinó el IC y el PV, medidas realizadas en forma independiente por dos radiólogos expertos. Se evaluó el grado de correlación entre los dos observadores utilizando el coeficiente de Pearson (p<0.01). Además, se calculó la diferencia de los índices obtenidos según las proyecciones, creando una variable para cada diferencia y se determinó la diferencia promedio de los índices según edad y sexo. Resultados: se analizaron 158 pacientes, 85 mujeres (54%) y 73 hombres (46%). El promedio de edad fue de 35 ± 7 años, con rango entre 18 y 65, siendo de 36 ± 12.6 años para las mujeres y de 35.5 ± 11.2 para hombres. Se encontraron valores para el PV en la proyección vertical en inspiración de 4.81 cm ± 0.572 (DS) para mujeres y de 5.11 cml- 0.654 (DS) para hombres (valor de p< 0.05); el IC en la misma proyección para las mujeres es de 0.43 ± 0.045 y en los hombres de 0.45 ± 0.050 (DS) (valor de p < 0.05). En la proyección decúbito en espiración, el PV para mujeres fue de 5.99 cm ±0.882 (DS) y para los hombres de 6.46 cm ±0.855 (SD) (valor de p< 0.05); el IC de las mujeres es de 0.52 ±0.047 (DS) y de los hombres de 0.51 ±0.050 (DS) (valor de p > 0.05). Conclusión: la variabilidad en hombres con el cambio de posición a decúbito en espiración es de 0.06 para el IC y de 1.35 cm para el PV. En las mujeres la variabilidad es de 0.09 para el IC y de 1.18 cm para el PV independiente de la edad. Se encontró que los hallazgos se correlacionan con las escasas publicaciones, pero los datos obtenidos en nuestra muestra poblacional son menores que los referidos en la literatura internacional.

Size effects under a strong magnetic field: Hall effect induced by electron-surface scattering on thin gold films deposited onto mica substrates under high vacuum.

We report measurements of the Hall effect performed on 4 gold films evaporated onto mica substrates where the signal arises primarily from electron-surface scattering. The measurements were performed at low temperatures T (4 K < or = T < or = 50 K) under high magnetic field strengths B (1.5 T < or = B < or = 9 T), with B oriented perpendicular to the films.

E-learning experience: a teaching model with undergraduate surgery students in a developing country.

Colombian medical students do not have an effective approach to electronic facilities in situ or at home, in contrast with most of American and European medical programs. Our aim is to help medical students to handle current biomedical data, specifically surgical information, in the benefit of patients, themselves and the community via ICT. The model implemented as a pilot study had a good acceptance amongst undergraduate surgery students and faculty.