Abstract In this work, we theoretically and experimentally study the issue of the spontaneous capillary rise of a viscous liquid in wedge-shaped tilted cells, with very short angles of aperture, α. We provide the equilibrium profiles y s e and, by means of the Reynolds lubrication equations, we find the time-dependent profiles and the dynamic evolution of the meniscus close to the edge of the wedge, as a function of time, which follow power laws of the form y s ∼ t 1 / 3. Experiments performed at various inclinations are consistent with our theoretical results.

Background: The COVID-19 pandemic posed a great strain in health services. Aim: To describe the epidemiological and clinical features of patients with SARS-CoV-2 admitted to a regional hospital in southern Chile between April and August 2020. Material and Methods: Clinical records of all hospitalized patients with RT-PCR (+) for SARS-CoV-2 were retrospectively analyzed. Results: During the study period 226 patients aged 55 ± 18 years (55% men) were admitted. The main comorbidities were high blood pressure in 45%, diabetes in 31% and obesity in 21%. The main symptoms were dyspnea in 70%, cough in 69%, fever in 62% and myalgia in 47%. Pneumonia was the main cause of admission in 66%. Images on admission were compatible with pneumonia in 81%, and with a typical COVID-19 pattern in 84%. In 76% there was five-lobe involvement. Eighty-seven cases (39%) were admitted to critical care, with an APACHE score of 10.9 ± 7.1. Invasive mechanical ventilation was used in 16%, 30% required prone position and 13%, a high-flow nasal cannula. The mean stay in critical care was 13.3 days. The mean duration of invasive mechanical ventilation was 14.1 days. Antimicrobials were used in 55% and dexamethasone in 36%. Twenty-two (9.7%) patients aged 71.7 ± 14 died. A Charlson comorbidity index > 3, heart failure and connection to invasive mechanical ventilation were independent risk factors for death. An age > 65 years alone and other comorbidities were not risk factors. Conclusions: Viral pneumonia is the main cause of hospitalization for COVID-19, usually extensive and bilateral. The greater severity and poor prognosis of these patients are mainly related to comorbidities.

Background: In a decade, we faced two pandemic viruses, influenza A H1N1pdm09 and SARS CoV-2, whose most serious manifestation is pneumonia. Aim: To compare the clinical, epidemiological and management aspects of pneumonias caused by each pandemic virus in adults requiring hospitalization. Material and Methods: Comparative, observational study carried out at a regional Chilean hospital, including 75 patients with influenza A H1N1pdm09 prospectively studied in 2009 and 142 patients with SARS-CoV-2 studied in 2020. Results: Patients with SARS-CoV-2 pneumonia were older (56 and 39.7 years respectively, p < 0.01) and had significantly more comorbidities. Cough, fever and myalgias were more frequent in influenza. Dyspnea was more frequent in COVID-19. Patients with COVID-19 had more extensive lung involvement and a longer hospitalization (13.6 and 8.6 days respectively, p = 0.01). There was no difference on ICU admission requirements and mortality attributable to pneumonia. Patients with influenza had greater APACHE scores and a higher frequency of a PaO2/FiO2 ratio ≤ 200. During COVID-19pandemic chest sean replaced x-ray examination. Also high-flow nasal cannulas and awake prone position ventilation were added as treatments. Conclusions: COVID-19 patients were older, had fewer classic flu symptoms but more dyspnea and longer hospitalization periods than patients with influenza.

Abstract We report a theoretical study aimed at determining the temperature distribution of a homogeneous, fluid-saturated porous medium initially at a low temperature, into which a constant flow rate of hot water is injected. The size of the heated region is assumed to be large compared to the radius of the injection pipe, which is idealized as a line source of mass and heat. The temperature distribution is found to be self-similar and to depend on a single dimensionless parameter which is a Peclet number.

Abstract: Introduction: Total navigated knee replacement uses a computer-guided system, which provides immediate information on pre-cut trans-operative conditions of the knee, in relation to pelvic limb alignment. Material and methods: Observational, descriptive study conducted from March 2003 to February 2019. Total bilateral knee replacement was performed at the same time surgically by a surgeon, evaluating function and pain on the WOMAC, EVA, and range of motion scores of both knees. Two groups of patients were studied: the first represents presurgical and the second post-surgical. Student’s t-test and χ2 were applied for statistical analysis. Results: 31 patients (62 prostheses), 83.9% of the female sex and 16.1% male, average age 67.32 years, average follow-up 6.55 years (± 3.8) were studied. It was identified that 100% of the patients in both knees have a deviation between 0o and 2o measured in the mechanical axis. The WOMAC scale showed an average of 22.71 ± 3.34 presurgical and 4.16 ± 1.84) post-surgical, with statistically significant differences. The average analog visual scale was 9.06 ± 0.814 presurgical and 2.35 ± 1.427 post-surgical. Conclusions: This technique is reliable, safe and satisfactory. Excellent clinical and radiographic results were evident regarding the positioning of prosthetic components.

Resumen: Introducción: La artroplastía total de rodilla navegada utiliza un sistema guiado por computadora que proporciona información inmediata de condiciones transoperatorias precorte de la rodilla, con relación a la alineación del miembro pélvico. Material y métodos: Estudio observacional, descriptivo, efectuado de Marzo de 2003 a Febrero de 2019. Se realizó artroplastía total de rodilla bilateral navegada en un mismo tiempo quirúrgico por un cirujano, evaluando función y dolor según las escalas WOMAC, EVA y arcos de movilidad de ambas rodillas. Se estudiaron dos grupos de pacientes: el primero representa prequirúrgicos y el segundo postquirúrgicos. Se aplicó prueba t de Student y χ2 para el análisis estadístico. Resultados: Se estudiaron 31 pacientes (62 prótesis), 83.9% del sexo femenino y 16.1% del masculino, edad media 67.32 años, media de seguimiento 6.55 años (± 3.8). Se identificó que 100% de los pacientes intervenidos en ambas rodillas tienen una desviación entre 0o y 2o medida en el eje mecánico. La escala WOMAC mostró una media de 22.71 ± 3.34 prequirúrgica y 4.16 ± 1.84 postquirúrgica, con diferencias estadísticamente significativas. La escala visual análoga media fue de 9.06 ± 0.814 prequirúrgico y 2.35 ± 1.427 postquirúrgico. Conclusiones: Esta técnica es confiable, segura y satisfactoria. Se evidenciaron excelentes resultados clínicos y radiográficos respecto al posicionamiento de los componentes protésicos.

The current coronavirus (COVID-19) pandemic has led to a large number of measures at the individual and global level, seriously affecting healthcare systems. Although COVID-19 does not directly involve specialists in Orthopedics, we are nevertheless compelled to implement preventive hospital measures aimed at reducing chances of infection during our specific procedures. This literature review aims to provide basic dynamic information on how healthcare specialists should act in surgical areas when facing suspicious/confirmed cases of COVID-19. We advocate the design of updated workflow processes for patient care before, during and after surgery.

La pandemia actual ocasionada por el coronavirus (COVID-19) ha promovido el desarrollo de gran cantidad de medidas en el ámbito individual y global, que afectan gravemente a los sistemas de salud. Aunque la epidemia no involucra directamente a los especialistas en Ortopedia y Traumatología, indirectamente, nos vemos compelidos a implementar medidas hospitalarias preventivas tendientes a disminuir las posibilidades de contagio durante nuestros procedimientos específicos. Esta breve revisión bibliográfica pretende aportar información dinámica básica respecto a de qué manera actuar como especialistas en las áreas quirúrgicas ante casos sospechosos/confirmados de COVID-19. Promovemos el diseño de planes de trabajo para la atención de pacientes antes de la cirugía, durante esta y después.

Los metales pesados continuamente se transportan a través de la superficie del suelo, los organismos, el agua y la atmósfera, haciéndose parte del ciclo biogeoquímico, como procesos complejos que se interrelacionan en la naturaleza, generando contaminación y problemas ambientales, sociales, económicos y políticos a las poblaciones, las elevadas concentraciones de metales pesados en las cuencas hídricas se han convertido en alto riesgo para la salud humana, siendo muy dañinos por no ser biodegradable, larga vida medica biológica y su potencial de acumulación en diferentes partes del cuerpo, la zona de estudio es una un área de extensión agrícola mayor, genera un movimiento económico en la población, que directa e indirectamente dependen de la agricultura y ganadería; el estudio se dedicó a determinar mediante la técnica de análisis por fluorescencia de rayos X los niveles de concentraciones de metales pesados en sedimentos del agua en la microcuenca del río Huancaray para el periodo de estiaje y de lluvias, las precipitaciones acumulada anual es 695 mm, la concentración de metales pesados en muestras de sedimentos recogidas de 05 puntos entre 10 a 20 cm de profundidad se determinó por la técnica de fluorescencia de rayos X con fuente de Cad-109, los elementos pesados detectados a distintas concentraciones fueron K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Br, Rb, Sr, Y, Zr, Nb y Ba, las concentraciones de la mayoría de los elementos detectados superan a los valores de los materiales de referencia, no existe diferencia significativa para periodo de lluvias y estiaje, las aguas de la microcuenca del río Huancaray parcialmente se encuentra contaminadas hacia la parte alta de la microcuenca, mientras la parte baja está totalmente contaminada por metales pesados, las elevadas contaminación se atribuye a fuentes naturales y antropogénicas.

Heavy metals are continuously transported through the surface of the soil, organisms, water and atmosphere, becoming part of the biogeochemical cycle, as complex processes that are interrelated in nature, generating pollution and environmental, social, economic and political problems to populations, the high concentrations of heavy metals in the water basins have become a high risk for human health, being very harmful for not being biodegradable, long biological medical life and its potential for accumulation in different parts of the body, the study area is a larger agricultural area, generates an economic movement in the population, which directiy and indirectiy depend on agriculture and livestock; The study was dedicated to determine by means of the technique of analysis by fluorescence of X rays the levels of concentrations of heavy metals in sediments of the water in the micro watershed of the Huancaray river for the period of low water and of rains, the accumulated annual precipitation is 695 mm, the concentration of heavy metals in samples of sediments collected from 05 points between 10 to 20 cm of depth was determined by the technique of fluorescence of X rays with source of Cad-109, the heavy elements detected to different concentrations were K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Br, Rb, Sr, Y, Zr, Nb and Ba, the concentrations of most of the detected elements exceed the values of the reference materials, there is no significant difference for rainy and low water periods, the waters of the micro-basin of the Huancaray river are partially contaminated towards the upper part of the micro-basin, while the lower part is totally contaminated by heavy metals, the high contamination is attributed to natural and anthropogenic sources.

Abstract In this work, the experimental and numerical results from the study of the effects caused in a submerged jet flow by the change in the wall thickness of the circular tube from which said flow originates are presented. For small values of the Reynolds number Re (Re ≈ 0:11), four cases, regarding the ratio of pipe wall thickness to inner radius, are considered: (I) pipe thickness is a fourth of the radius, (II) pipe thickness is half the radius, (III) pipe thickness is equal to the radius and (IV) pipe thickness is three times the radius. The Particle Image Velocimetry (PIV) technique was used to experimentally obtain the velocity and streamlines distributions. A numerical code based on the finite difference method was developed to solve the motion governing equations, and the numerical results were compared with the values obtained experimentally.

Fluctuating asymmetry is characterized by subtle and random deviations in bilaterally symmetrical features, and directional asymmetry is characterized by a distribution skewed towards one side (left or right). For the analysis of both types in the skull of the companion rabbit, 45 specimens were studied. Cranial morphology was revealed by 8 sagittal and 16 bilateral (on both sides of the skull) Cartesian coordinates on the ventral level, using geometric morphometric. According to the results, there were differences between left and right configurations, located mainly on the basis. This fact may be interpreted as a manifestation of lateralized masticatory activity.

La asimetría fluctuante se caracteriza por desviaciones sutiles y aleatorias en rasgos bilateralmente simétricos, y la asimetría direccional por una distribución sesgada hacia uno de los lados (derecho o izquierdo). Para el análisis de ellas en el cráneo del conejo de compañía, se estudiaron 45 especímenes. La morfología craneal fue revelada mediante el registro de coordenadas cartesianas de 24 hitos anatómicos sagitales (8) y bilaterales (en ambos lados del cráneo, 16), a nivel ventral, y se aplicaron métodos de morfometría geométrica. Los resultados indican diferencias entre las configuraciones derecha e iz- quierda del cráneo, sobre todo a nivel de la base. Esto podría interpretarse como una manifestación de la actividad masticatoria lateralizada.

Abstract In this work, we show through experiments, using cohesionless granular materials, that a simple formula proposed to estimate the granular outflow from orifices in thick sidewalls is also valid for thin sidewalls. The use of such a formula entails the approximate validity of the classical Hagen and Beverloo formulas for granular samples composed of small and large grains, respectively. Also, an estimation of the involved error when the wall thickness is left aside is given.

Abstract This paper discusses experimentally the advance and distribution of preformed, wet aqueous foam flow when it is injected into a horizontal rectangular cell with different transversal opening channels. Speeds of the simultaneous foam fronts in each channel were obtained experimentally. The relationship between bubble size and the opening of the channel, the apparent viscosity and the friction factor were obtained with experimental data. Experiments were performed under three different injection pressures. The diversion of the foam flow into the transversal channel was also studied. With these experiments we show that the foam flow stream is affected by sudden changes in the geometry.

Resumen El manejo quirúrgico de las lesiones por armas de fuego al complejo cigomaticomaxilar representa una situación compleja en la práctica maxilofacial que debe ser abordada con extrema cautela, debido a las complicaciones que pueden surgir durante el tratamiento y los potenciales problemas residuales. La zona infraorbitaria es la segunda área más común de lesiones en la cara, representando hasta 45% de las fracturas mediocraneales. El presente caso es de un masculino de 54 años de edad, que sufrió trauma ocasionado por la parte trasera de un rifle de caza que causó un impacto en sentido oblicuo hacia el lado lateral inferior del complejo infraorbitario. El paciente fue estabilizado con esquema antibiótico y analgésico, el diagnóstico fue: fractura cominuta del piso de la órbita, con consecuente comunicación al seno maxilar, fractura no desplazada de la sutura frontomalar, fractura no desplazada del arco cigomático, y lesión con pérdida de tejido óseo en la región petrosa del hueso temporal. El tratamiento quirúrgico consistió en reducción de las fracturas y fijación rígida de las estructuras. Al control post operatorio el paciente refirió acufenos y fotopsia ocasional, no presentando otras alteraciones. Se ha descrito en la literatura diferentes abordajes para el manejo de estos traumatismos, sin embargo cada caso debe ser individualizado y evaluado de forma minuciosa para que éste, sea el adecuado.

Abstract The surgical management of firearm injuries to the zygomaticomaxillary complex is a topic that needs to be addressed with much care. The complications that can arise during treatment, as well as the potential residual problems that can appear, lead to the need of recognizing these injuries as a maxillofacial treatment challenge. The infraorbital zone is the second most common area of injury in the face, accounting for up to 45% of midfacial fractures. The case presented is of a 54 year old man affected by the backward firing of a gun rifle that caused an oblique impaction towards the posterior lateral inferior side of the infraorbital complex. He was rapidly stabilized with an antibiotic and analgesic scheme, yet presented the following: a comminute fracture of the orbit floor with consequent communication towards the maxillary sinus, a non-displacing fracture of the frontomalar suture, a non-displacing fracture of the zygomatic arch and a lesion with loss of osseous tissue in the petrous region of the temporal bone. Rigid fixation followed stabilization, and the area was covered with a titanium mesh. Occasional tinnitus and photopsia were reported by the patient upon return, yet all other evaluated factors were in order. There have been different forms of management described in the literature, and it is recognized that each patient has different needs, therefore each case must be closely evaluated, so it is approached in the most appropriate manner.

Objective Apply three prognostic models “online” (Nothingham index (NPI), Adjuvantonline! (AO) and PREDICT used in routine oncology practice in order to stratify patients and define the use of adjuvant therapies in patients with stage I breast cancer (BC) to evaluate its correlation and overall survival (OS) in our population. Methods We obtained patients' medical records data with invasive BC T1N0M0, treated at the Cancer Center of the Pontificia Universidad Católica de Chile, Santiago, Chile, from January 1997 to December 2003. Results We analyzed data from 125 patients. Median age was 55 years (35 80). Most tumors were infiltrating ductal carcinoma (72.8%), estrogen receptor positive (88.8%), 80% received endocrine therapy (ET). The estimated ET and chemotherapy benefit was not significantly different according to the AO and PREDICT models (1.3% and 1% for CT, p = 0.13, 0.9% and 1% for ET p = 0.8, respectively). The estimated median OS on NPI (96%) was higher than calculated by AO (90.9%) and PREDICT (92.5%). Interestingly disease specific mortality estimated was 3%, similar to that observed (3.2%). While the estimated median OS by all models in the group of deceased patients was lower than in surviving, this difference did not reach statistical significance (p = 0.85). Conclusion The prognostic models applied effectively predict OS in Chilean patients with T1N0M0 BC, but in this series, they do not sufficiently discriminate patients with poor prognosis. The addition of co -morbidities to AO does not alter the results.

Resumen Objetivo Aplicar tres modelos pronósticos “online” (índice pronóstico de Nothingham (NPI), Adjuvantonline! (AO) y PREDICT utilizados en la práctica oncológica para estratificar a pacientes y definir el uso de terapias adyuvantes en pacientes con cáncer de mama (CM) precoz, para evaluar su correlación y predicción de sobrevida en nuestra población. Métodos Obtuvimos datos clínicos de pacientes con CM invasor T1N0M0, tratados en el Centro de Cáncer de la Pontificia Universidad Católica de Chile, Santiago, Chile, desde enero de 1997 hasta diciembre de 2003. Resultados Analizamos datos de 125 pacientes. Edad mediana fue 55 años (35-80). La mayoría de los tumores fueron carcinomas ductales infiltrantes (72,8%), receptor de estrógeno (RE) positivos (88,8%), 80% recibieron terapia endocrina (TE). El beneficio estimado de la TE y la quimioterapia (QT) en la sobrevida global (SG), determinadas según AO y PREDICT, no fueron significativamente diferentes (1,3% y 1% para QT, p = 0,13; 0,9% y 1% para TE, p = 0,8; respectivamente). El modelo NPI estimó una mediana de SG superior (96%) a la calculada por AO (90,9%) y PREDICT (92,5%). La mortalidad específica por CM fue de 3%, similar a lo observado (3,2%). La mediana de SG estimada por todos los modelos en el grupo de pacientes fallecidos no fue estadísticamente diferente al grupo de sobrevivientes (p = 0,85). Conclusión Los modelos pronósticos predicen apropiadamente la SG en pacientes con CM precoz; sin embargo, en esta serie, no discriminaron pacientes de mal pronóstico.

Breast cancer is the leading cause of cancer death in Chilean women. While most patientes are cured, five percent of cases present with advanced disease initially and up to 20-30% of patients with localized disease may suffer systemic recurrences. The majority of breast neoplasms are dependent on the estrogenic stimulus, hence the deprivation of estrogen is the main therapeutic strategy. Recently, the use of molecular targeted therapies in combination with endocrine therapy has been successful in improving the survival outcomes of advanced breast cancer, with fewer side effects than those produced by conventional chemotherapy. Knowledge of the mechanisms of action of these new therapies, their toxicities, resistance pathways and patient selection to achieve the best therapeutic benefits are relevant aspects in the management of the disease. We present a review of the current state of management of hormone-dependent metastatic breast cancer with emphasis on the use of endocrine therapies combined with molecular therapies.

Resumen El cáncer de mama es la primera causa de muerte por cáncer en mujeres chilenas. Mientras la mayoría de las personas logra curarse de esta enfermedad, un 5% de los casos se presenta inicialmente con enfermedad avanzada y hasta un 20-30% de pacientes con enfermedad localizada pueden sufrir recurrencias sistémicas. La mayoría de las neoplasias mamarias son dependientes del estímulo estrogénico, de allí que la deprivación de estrógenos es la principal estrategia terapéutica. Recientemente, el uso de terapias molecularmente dirigidas en combinación con la terapia endocrina ha logrado mejorar los resultados de sobrevida del cáncer de mama avanzado, con menos efectos colaterales que aquellos producidos por la quimioterapia convencional. El conocimiento de los mecanismos de acción de estas nuevas terapias, sus toxicidades, vías de resistencia y selección de pacientes para lograr los mejores beneficios terapéuticos son aspectos relevantes en el manejo de la enfermedad. Presentamos una revisión del estado actual del manejo del cáncer de mama metastásico hormonodependiente con enfásis en el uso de terapias endocrinas combinadas con terapias moleculares.

ABSTRACT Cannabis is the drug most often used by persons with schizophrenia. However, the relationship between cannabis use and schizophrenia development has not yet been fully clarified. This short communication aims to highlight some studied links between cannabis use and schizophrenia development. The authors summarize some of the main findings of several investigations done on this topic, including studies on brain white matter, brain reward circuit, hippocampal pathophysiology, brain volume, age of psychosis onset, and characteristics of cannabis use, personality traits, genetics, neurochemistry, and stress response. The authors agree with the notion that there are two most convincing hypotheses regarding the link between cannabis and schizophrenia: 1. Cannabis as a contributing cause and, 2. Shared vulnerability. The authors stress that cannabis use does not in itself cause a psychotic disorder; however, both early use and heavy use of it are more likely in individuals with a vulnerability to psychosis. The use of cannabis is arguably the most modifiable environmental risk factor for schizophrenia, so it is necessary to ensure a public health warning that cannabis use can increase the risk of psychotic disorders.

RESUMEN El cannabis es la droga más utilizada por personas con esquizofrenia. Sin embargo, la relación entre el consumo de cannabis y el desarrollo de esquizofrenia aún no ha sido completamente aclarada. Esta comunicación corta pretende destacar algunos vínculos estudiados entre el consumo de cannabis y el desarrollo de esquizofrenia. Los autores resumen algunos de los principales hallazgos de varias investigaciones realizadas sobre este tema, incluyendo estudios sobre la sustancia blanca del cerebro, el circuito de recompensa cerebral, la fisiopatología del hipocampo, el volumen cerebral, la edad de inicio de la psicosis, las características del uso de cannabis y los rasgos de personalidad, la genética, la neuroquímica, así como la respuesta al estrés. Los autores concuerdan con la noción de que hay dos hipótesis más convincentes sobre el vínculo entre el cannabis y la esquizofrenia: 1. Cannabis como causa contribuyente y, 2. Vulnerabilidad compartida. Los autores hacen hincapié en que el consumo de cannabis no provoca por sí mismo un trastorno psicótico; sin embargo, tanto el uso temprano como el uso intensivo del mismo son más probables en individuos con una vulnerabilidad a la psicosis. El uso del cannabis es posiblemente el factor de riesgo medioambiental más modificable de la esquizofrenia, por lo que es necesaria una advertencia de salud pública de que el consumo de cannabis puede aumentar el riesgo de trastornos psicóticos.