Cleft lip and palate surgery simulator: Open source simulation model.

Objective: Cleft lip and palate is the most common craniofacial birth anomaly and requires surgery in the first year of life. However, craniofacial surgery training opportunities are limited. The aim of this study was to present and evaluate an open-source cleft lip and palate hybrid (casting and three-dimensional (3D) printing) simulation model which can be replicated at low cost to facilitate the teaching and training of cleft surgery anatomy and techniques. Design: The soft tissue component of the cleft surgery training model was casted using a 3D printed 5-component mold and silicone. The bony structure was designed to simulate the facial anatomy and to hold the silicone soft tissue. Setting: Two groups, one group of trainees and one group of expert surgeons, at University Hospital Basel in Switzerland and Pontifical Catholic University of Chile in Santiago, Chile, tested the cleft lip and palate simulation model. Participants completed a Likert-based face and content validity questionnaire to assess the realism of the model and its usefulness in surgical training. Results: More than 70 % of the participants agreed that the model accurately simulated human tissues found in patients with unilateral cleft lip and palate. Over 60 % of the participants also agreed that the model realistically replicated surgical procedures. In addition, 80-90 % of the participants found the model to be a useful and appropriate tool for teaching the anatomy and surgical techniques involved in performing unilateral cleft lip and palate repair. Conclusion: This open-source protocol provides a cost-effective solution for surgeons to introduce the cleft morphology and surgical techniques to trainees on a regular basis. It addresses the current financial barrier that limits access to commercially available models during the early stages of surgeon training prior to specialization in the field.

Primary thyroid hemangioma, a rare diagnosis in a patient with a painless neck mass.

The aim of this case report is to demonstrate a case of primary thyroid hemangioma in a 62-year-old female who presented with a painless neck mass, treated with right hemithyroidectomy and diagnosed by surgical biopsy. Thyroid hemangiomas are rare, benign lesions which present a diagnostic challenge given the lack of specific imaging findings and clinical manifestations associated with them. However, accurate recognition of these lesions is important and can facilitate conservative, rather than surgical, management strategies. In this report, we discuss a case in a patient whose laboratory assessment raised concern for a thyroid paraganglioma, leading to surgical resection of what was ultimately a benign thyroid hemangioma. We also review the pathophysiology, clinical manifestations, differential diagnostic considerations, and imaging characteristics of thyroid hemangiomas across multiple modalities and discuss strategies for accurately diagnosing these lesions.

Bases anatómicas del colgajo anterolateral de muslo de flujo inverso / Anatomical basis of distally based anterolateral thigh flap

Introducción y objetivo: El colgajo anterolateral de muslo de base distal presenta una alternativa interesante para la reconstrucción de los defectos cutáneos de la rodilla.El motivo de este trabajo es el estudio anatómico de la arteria descendente de la circunfleja femoral lateral y su existencia o no de anastomosis distal, que nos permitirá la realización del colgajo basado distalmente.Material y método.Estudiamos diferentes ítems en 22 miembros inferiores formolizados: origen de la arteria, distancia desde la salida de la perforante de la arteria descendente hasta la piel, longitud y localización de la arteria descendente, anastomosis distal en el caso de que la hubiera, localización del punto pivote tomando como punto de referencia la esquina súpero-lateral de la patela y la suma de la longitud de la perforante, y la longitud de la arteria de la descendente que nos da la longitud del pedículo que podemos obtener al disecar el colgajo.Resultados.En relación con la anastomosis distal describimos 2 modelos. Modelo 1: no anastomosis, con una proporción del 45%; y modelo 2: anastomosis distal existente, con un 55%. En el modelo 2 establecemos a su vez 3 tipos de anastomosis: tipo 1, cuando la anastomosis se realiza con la arteria geniculada lateral superior, en un 42%; tipo 2, anastomosis con la arteria femoral profunda, en un 25%; y tipo 3, anastomosis con ambas, en un 33%.El punto pivote lo encontramos como media a 11 cm del borde superior de la patela. La longitud del pedículo presentó una media de 15 cm.Conclusiones.Nuestros resultados demuestran que el colgajo anterolateral de base distal es una adecuada alternativa para la cobertura de pérdidas de sustancia en la rodilla. Para emplearlo, debido a la diversidad anatómica, sería adecuado realizar una angiografía previa o una revisión intraoperatoria de la anastomosis distal. (AU)

Background and objective: The distally based anterolateral thigh flap is an interesting alternative for the reconstruction of skin defects of the knee.The reason for this paper is the anatomical study of the descending artery of the lateral circumflex femoral and the existence or not of a distal anastomosis that allows us to perform the distally based flap.Methods.Different items were studied in 22 embalmed lower limbs: origin of the artery, distance from the outlet of the perforator of the descending artery to the skin, length and location of the descending artery, distal anastomosis if any, location of the pivot point taking as a reference point the supero-lateral corner of the patella, and the sum of the length of the perforator and the length of the descending artery, which gives us the length of the pedicle that we can obtain by dissecting the flap.Results.Related to the distal anastomosis, we described 2 models. Model 1: no anastomosis, with a ratio of 45%, and model 2: there is an anastomosis in 55%. In model 2 we have established 3 types of anastomosis: type 1, when the anastomosis is performed with the superior lateral geniculate artery, in 42%; type 2, anastomosis with the deep femoral artery, in 25%; and type 3, anastomosis with both, in 33%. The pivot point was found an average of 11 cm from the upper edge of the patella.The length of the pedicle had an average of 15 cm.Conclusions.Our results demonstrate that the distally based anterolateral flap is an adequate alternative for knee soft-tissue reconstruction. Due to the anatomical diversity, angiography or intraoperative revision of the distal anastomosis would be appropriate to perform this flap. (AU)

COVID-19 and Spontaneous Pneumomediastinum: A case series.

COVID-19 is a relatively new and rapidly emerging disease. Given current knowledge of the disease process, it is of the utmost importance to gain further insight into its different clinical manifestations. In this report we describe three cases involving Hispanic males with COVID-19 all of whom developed pneumomediastinum during their hospital course. We want to emphasize the importance of this adverse event despite their non-smoking history and the exclusion of positive pressure ventilation. Frequent chest radiographs help with early recognition of this disease process. Early detection of pneumomediastinum is important as this could lead to worse morbidity if left unrecognized despite its usually benign nature.

Perfil epidemiológico de neoplasias epiteliales de glándulas salivales / Epithelial tumors of salivary glands: review of 286 pathology reports

Background:: Epithelial tumors of the salivary glands, including benign tumors and aggressive malignancies with different prognoses, are uncommon. Aim: To describe the frequency and distribution of salivary gland tumors according to age, gender and anatomical location. Material and Methods: Review of pathological reports of salivary gland tumors of a Pathology laboratory at a clinical hospital from 2006 to 2016. Results: Five hundred ninety salivary gland biopsies were reviewed. Of these, 286 (49%) were primary epithelial tumors of the salivary glands. Two hundred thirty (80%) were benign and 56 (20%) were malignant tumors. Regarding location, 274 (96%) were in the major salivary glands, and 12 (4%) in the minor salivary glands. The most common histological types were pleomorphic adenoma for benign tumors in 172 cases, followed by papillary cystadenoma lymphomatosum in 33 cases. Mucoepidermoid carcinoma was the most common malignant tumor in 14 cases. Conclusions: These results are similar to reports from abroad, however more studies are necessary to be able to establish a more representative and updated analysis.

Oral self-mutilation in Lesch-Nyhan Syndrome. Case Report. / Síndrome de Lesch-Nyhan y automutilación oral. Reporte de un caso.

INTRODUCTION: Lesch-Nyhan syndrome (LNS) is an inherited recessive X-related disorder caused by the deficiency of the enzyme hypoxanthin-guanine phosphorribosyl transferase (HPRT). Compul sive self-mutilation and dystonia occurs before the first year of age and is expressed by persistent bites on the oral mucosa, lips, tongue, fingers, and shoulders. The dental intervention performed on most of these patients is multiple tooth extraction to prevent serious secondary lesions. OBJECTIVE: To present a clinical case of LNS and describe pediatric dentistry management in patients with self-mutilating behavior. CLINICAL CASE: Male patient, 7 years old, LNS carrier. He was referred to the Dental Unit from the Department of Pediatric Neurology for evaluation and management of self-inflicted wounds on fingers, lips and cheeks associated with weight loss and decreased food intake. The surgical procedure consisted of multiple extractions, surgical remodeling of the residual alveolar ridges under general anesthesia. In the second postoperative month, the patient was discharged definitively, with an adequate nutritional status and no signs of self-mutilation in hands or oral cavity. CONCLUSIONS: Although LNS is rare, it is essential to know how to proceed in order to provide the best quality of life for patients and their families. Early tooth extractions, as an initial phase in severe cases, seem to be the most useful alternative to minimize damage.

Síndrome de Lesch-Nyhan y automutilación oral. Reporte de un caso / Oral self-mutilation in Lesch-Nyhan Syndrome. Case Report

Resumen: Introducción: El síndrome de Lesch-Nyhan (SLN) es un trastorno hereditario recesivo relacionado con el cromosoma X, causado por la deficiencia de la enzima hipoxantina-guanina fosforribosil transferasa (HPRT). La automutilación compulsiva y distonía ocurre antes del año de edad y se expresa con mordeduras persistentes en la mucosa oral, labios, lengua, dedos y hombros. La intervención odontológica realizada en la mayoría de estos pacientes es la extracción dental múltiple para prevenir lesiones graves secundarias. Objetivo: presentar un caso clínico de SLN y describir el manejo odonto-pediátrico en pacientes con conducta automutilatoria. Caso clínico: Paciente varón, 7 años de edad, portador de SLN. Fue referido a la Unidad de Odontología desde el Departamento de Neurología Pediátrica para la evaluación y manejo de heridas autoinfligidas en dedos, labios y mejillas asociadas a una pérdida de peso y disminución de la ingesta de alimentos. El procedimiento quirúrgico consistió en extracciones dentales múltiples, y remodelación quirúrgica de las crestas alveolares residuales, bajo anestesia general. Al segundo mes posquirúrgico el paciente fue dado de alta definitivamente, con un adecuado estado nutricional y sin signos de automutilación en manos ni en cavidad oral. Conclusio nes: A pesar, que el SLN es infrecuente, es esencial saber cómo proceder para dar la mejor calidad de vida a los pacientes y sus familias. Las extracciones tempranas del diente, como fase inicial en casos severos, parecen ser la alternativa más útil para minimizar el daño y el dolor por la automutilación.

Abstract: Introduction: Lesch-Nyhan syndrome (LNS) is an inherited recessive X-related disorder caused by the deficiency of the enzyme hypoxanthin-guanine phosphorribosyl transferase (HPRT). Compul sive self-mutilation and dystonia occurs before the first year of age and is expressed by persistent bites on the oral mucosa, lips, tongue, fingers, and shoulders. The dental intervention performed on most of these patients is multiple tooth extraction to prevent serious secondary lesions. Objective: To present a clinical case of LNS and describe pediatric dentistry management in patients with self-mutilating behavior. Clinical case: Male patient, 7 years old, LNS carrier. He was referred to the Dental Unit from the Department of Pediatric Neurology for evaluation and management of self-inflicted wounds on fingers, lips and cheeks associated with weight loss and decreased food intake. The surgical procedure consisted of multiple extractions, surgical remodeling of the residual alveolar ridges under general anesthesia. In the second postoperative month, the patient was discharged definitively, with an adequate nutritional status and no signs of self-mutilation in hands or oral cavity. Conclusions: Although LNS is rare, it is essential to know how to proceed in order to provide the best quality of life for patients and their families. Early tooth extractions, as an initial phase in severe cases, seem to be the most useful alternative to minimize damage.

[Epithelial tumors of salivary glands. Review of 286 pathology reports]. / Perfil epidemiológico de neoplasias epiteliales de glándulas salivales.

BACKGROUND: Epithelial tumors of the salivary glands, including benign tumors and aggressive malignancies with different prognoses, are uncommon. AIM: To describe the frequency and distribution of salivary gland tumors according to age, gender and anatomical location. MATERIAL AND METHODS: Review of pathological reports of salivary gland tumors of a Pathology laboratory at a clinical hospital from 2006 to 2016. RESULTS: Five hundred ninety salivary gland biopsies were reviewed. Of these, 286 (49%) were primary epithelial tumors of the salivary glands. Two hundred thirty (80%) were benign and 56 (20%) were malignant tumors. Regarding location, 274 (96%) were in the major salivary glands, and 12 (4%) in the minor salivary glands. The most common histological types were pleomorphic adenoma for benign tumors in 172 cases, followed by papillary cystadenoma lymphomatosum in 33 cases. Mucoepidermoid carcinoma was the most common malignant tumor in 14 cases. CONCLUSIONS: These results are similar to reports from abroad, however more studies are necessary to be able to establish a more representative and updated analysis.

A Case of a 34-Year-Old Female with Acute Hypoxemic Respiratory Failure and Proximal Muscle Weakness.

Wound associated botulism is an unusual presentation. Early detection of this potentially life-threatening illness can significantly shorten length of hospital stay and improve prognosis. We present a case of a 34-year-old female with a history of heroin abuse who presented to the ED with acute respiratory failure, diplopia, and proximal muscle weakness. There was early concern for wound botulism as the instigating process. After discussion with the CDC, she was given equine serum heptavalent botulism antitoxin. Laboratory analysis later confirmed our suspicion. Symptoms improved and the patient was liberated from mechanical ventilation on day 14 and discharged from the hospital on day 23.

[Endoscopic treatment in chronic pancreatitis: long-term results in 18 patients]. / Tratamiento endoscópico en la pancreatitis crónica: seguimiento a largo plazo.

BACKGROUND: Intraductal stones, ductal abnormalities and pancreatic pseudocysts are part of chronic pancreatitis (CP). The goal of treatment is pain relief, resolution of local complications and relapse prevention. Endoscopic therapy (ET) can be considered in those who do not respond to medical treatment. AIM: To evaluate the indication, immediate and long-term results of ET in CP patients. PATIENTS AND METHODS: Review of a database of patients with CP analyzing results of ET in 18 patients aged 16 to 60 years (13 males). Demographics, etiology, endoscopic technique, indication for treatment, pain relief, relapses and complications were recorded. RESULTS: The etiology of CP was alcohol consumption in 5, idiopathic in 11, hereditary in one and autoimmune in one case. The follow-up period was 6 months to 14 years. Seven patients had diabetes mellitus type 3c and eight had moderate to severe exocrine pancreatic insufficiency. Pancreatic papillotomy was performed in all patients, with removal of some stones, without attempting a complete clearance of the pancreatic duct. In addition, a 7-10 French stent was placed in the main pancreatic duct in 15 patients with varying permanence (months to years). The stent was changed guided by recurrence of clinical symptoms. During the follow-up period, 10 patients remained asymptomatic and in three, pain or relapse were significantly reduced. Stenting failed in one patient for technical reasons. Two patients were operated. There were neither immediate nor late complications from ET. CONCLUSIONS: Long-lasting improvement of CP was observed in 13 of 18 patients treated with ET, without complications associated with the procedure.

Body-scaled affordances in sensory substitution.

The research field on sensory substitution devices has strong implications for theoretical work on perceptual consciousness. One of these implications concerns the extent to which the devices allow distal attribution. The present study applies a classic empirical approach on the perception of affordances to the field of sensory substitution. The reported experiment considers the perception of the stair-climbing affordance. Participants judged the climbability of steps apprehended through a vibrotactile sensory substitution device. If measured with standard metric units, climbability judgments of tall and short participants differed, but if measured in units of leg length, judgments did not differ. These results are similar to paradigmatic results in regular visual perception. We conclude that our sensory substitution device allows the perception of affordances. More generally, we argue that the theory of affordances may enrich theoretical debates concerning sensory substitution to a larger extent than has hitherto been the case.

[Hepatitis E virus seroprevalence: a reappraisal]. / Re-evaluación de seroprevalencia de virus hepatitis E.

Reported seroprevalence of hepatitis E virus (HEV) in developed countries is between 0.3-53%. Published data relies on the assays used and its technical performance. Sensitivity on new available tests has improved, which has changed HEV seroprevalence around the world. We re-evaluated retrospectively, 178 serum samples of patients with previous anti HEV IgG determination between 2009 and 2012. Initial analysis was performed with ELISA kit Genelabs (Singapore), with 7.3% positivity. The reevaluation was done with ELISA kit AccuDiag TM HEV-IgG (Diagnostic Automation, United States), with reported sensitivity and specificity over 99.8%. With the new assay, 32.6% positive samples were found, significantly greater to the previous result (p<0.001) (4.5 times more). There were no differences in gender but a significant association between age and HEV IgG seropositivity was found (p<0.001). This suggests that previous testing might have underestimated HEV seroprevalence in Chile, which should be reevaluated using the new available test.

Tratamiento endoscópico en la pancreatitis crónica: seguimiento a largo plazo / Endoscopic treatment in chronic pancreatitis: long-term results in 18 patients

Background: Intraductal stones, ductal abnormalities and pancreatic pseudocysts are part of chronic pancreatitis (CP). The goal of treatment is pain relief, resolution of local complications and relapse prevention. Endoscopic therapy (ET) can be considered in those who do not respond to medical treatment. Aim: To evaluate the indication, immediate and long-term results of ET in CP patients. Patients and Methods: Review of a database of patients with CP analyzing results of ET in 18 patients aged 16 to 60 years (13 males). Demographics, etiology, endoscopic technique, indication for treatment, pain relief, relapses and complications were recorded. Results: The etiology of CP was alcohol consumption in 5, idiopathic in 11, hereditary in one and autoimmune in one case. The follow-up period was 6 months to 14 years. Seven patients had diabetes mellitus type 3c and eight had moderate to severe exocrine pancreatic insufficiency. Pancreatic papillotomy was performed in all patients, with removal of some stones, without attempting a complete clearance of the pancreatic duct. In addition, a 7-10 French stent was placed in the main pancreatic duct in 15 patients with varying permanence (months to years). The stent was changed guided by recurrence of clinical symptoms. During the follow-up period, 10 patients remained asymptomatic and in three, pain or relapse were significantly reduced. Stenting failed in one patient for technical reasons. Two patients were operated. There were neither immediate nor late complications from ET. Conclusions: Long-lasting improvement of CP was observed in 13 of 18 patients treated with ET, without complications associated with the procedure.

Fascioliasis hepática humana: resistencia al tratamiento con triclabendazol / Resistant human fasciolasis: Report of four patients

Human fascioliasis is a parasitic zoonosis that affects the liver of human and herbivorous animals. In chronic cases, its diagnosis is confirmed by direct visualization of parasitic eggs in stool examination, by positive testing for Fasciola hepatica antigens in stools, or by direct observation of parasites by endoscopic retrograde cholangiography or surgery. In acute cases, serological reactions as immunoblothing or detection of parasite antigens in the blood are useful. The treatment of choice is triclabendazole. However, parasite resistance in animals, as well as in man, has been reported to this drug. We report four patients in whom the parasitic infection persisted despite a course of treatment with triclabendazole.

Effect of Pt nanoparticles on the optical gas sensing properties of WO3 thin films.

Thin films of tungsten trioxide were deposited on quartz substrates by RF magnetron sputtering. Different annealing temperatures in the range from 423 to 973 K were used under ambient atmosphere. The influence of the annealing temperature on the structure and optical properties of the resulting WO3 thin films were studied. The surface morphology of the films is composed of grains with an average size near 70 nm for the films annealed between 773 and 973 K. Some of the WO3 thin films were also coated with Pt nanoparticles of about 45 nm in size. Spectrometric measurements of transmittance were carried out for both types of WO3 samples in the wavelength range from 200-900 nm, to determine the effect of the exposure to two different gases namely H2 and CO. Films showed fast response and recovery times, in the range of few seconds. The addition of Pt nanoparticles enables reducing the operation temperature to room temperature.

[Resistant human fasciolasis: report of four patients]. / Fascioliasis hepática humana: resistencia al tratamiento con triclabendazol.

Human fascioliasis is a parasitic zoonosis that affects the liver of human and herbivorous animals. In chronic cases, its diagnosis is confirmed by direct visualization of parasitic eggs in stool examination, by positive testing for Fasciola hepatica antigens in stools, or by direct observation of parasites by endoscopic retrograde cholangiography or surgery. In acute cases, serological reactions as immunoblothing or detection of parasite antigens in the blood are useful. The treatment of choice is triclabendazole. However, parasite resistance in animals, as well as in man, has been reported to this drug. We report four patients in whom the parasitic infection persisted despite a course of treatment with triclabendazole.

Action-contingent vibrotactile flow facilitates the detection of ground level obstacles with a partly virtual sensory substitution device.

This research considers a sensory substitution device that allows the exploration of the environment through normal walking, leaning and standing. The device includes an array of 24 coin motors placed vertically on the torso, with the intensity of vibration of each motor being a function of the distance to the first-encountered object. Thresholds were determined for the detection of ground-level obstacles (raised target platforms). On average, blindfolded participants were able to detect platforms with heights of 9 to 17 cm, but the thresholds differed for different experimental conditions. Experiment 1 showed that the detection threshold is lower for use with exploratory movements than for use without exploratory movements. Experiments 2 and 3 compared dynamic groups, who made exploratory movements and received vibrotactile flow contingent on their movements, with yoked groups, who received the same vibrotactile flow as the dynamic groups independently of their own movements. The detection thresholds were lower for the dynamic groups than for the yoked groups, meaning that the contingency of vibrotactile flow on exploratory movements is important beyond a higher-order vibrotactile flow by itself.

Judgements of time to contact are affected by rate of appearance of visible texture.

More fine-grained texture becomes visible if the distance between an observer and an object or surface is reduced. This article illustrates with a schematic example that the inverse rate of the relative appearance of visible texture provides information about time to contact if the observer has a constant visual acuity and the texture has a certain scale-independent structure. An experiment is reported in which texture appearance was manipulated. Participants were asked to make forced-choice time-to-contact judgements. A small but significant effect indicates that the judgements were affected by the rate of appearance of the texture. It is concluded that observers use this type of information.

Effect of root feeding by Diaprepes abbreviatus (Coleoptera: Curculionidae) larvae on leaf gas exchange and growth of three ornamental tree species.

Diaprepes abbreviatus L. (Coleoptera: Curculionidae), feeds on a variety of ornamental plants grown in southern Florida. Studies were conducted to evaluate the effects of root feeding by D. abbreviatus larvae on leaf gas exchange and growth of three ornamental tree species commonly grown in southern Florida that are known hosts of this weevil: green buttonwood, Conocarpus erectus L.; live oak, Quercus virginiana Mill.; and pygmy date palm, Phoenix roebelenii O'Brien. These hosts were grown in containers and infested with weevil larvae. Net CO2 assimilation, transpiration, and stomatal conductance of CO, were measured monthly. Leaf, stem, and root fresh and dry weights of each species also were determined. In one of two tests, larval root feeding significantly reduced net CO2 assimilation, transpiration, and stomatal conductance of CO2 of infested green buttonwood trees. Leaf gas exchange of live oak was not affected by larval infestation. In addition to testing cumulative effects of multiple infestations of larvae, the effects of incremental infestations on leaf gas exchange and fresh and dry weights also were tested for each plant species. Net CO2 assimilation, transpiration, stomatal conductance of CO2, and dry weights of green buttonwood were reduced as a result of larval root feeding, whereas there was no effect of incremental larval infestations on leaf gas exchange of live oak or pygmy date palm within the experimental time frame. There was no effect of incremental larval infestations on dry weights of live oak, but leaf, stem, and dry root weight of pygmy date palm were lower for infested plants than for noninfested plants. Overall, green buttonwood was more susceptible to larval root feeding damage than either live oak or pygmy date palm.

Efectos adversos y cuidados de enfermería en la administración de ritodrina / Adverse effects and nursing care in ritodrine administration

Cuando las contracciones uterinas comienzan antes del término, entre las semanas 20-37 de gestación, es a veces necesario detener el trabajo del parto prematuro hasta que el feto madure lo suficiente para asegurar su supervivencia. El tratamiento farmacológico se realiza con relajantes uterinos; actualmente se emplean los beta-2-adrenérgicos. En nuestro estudio hemos utilizado ritodrina. Los objetivos del trabajo son detectar y cuantificar los efectos adversos del fármaco y prestar cuidados de enfermería en su administración para una mejor prevención de éstos. Se ha realizado un estudio observacional en una muestra de 50 pacientes diagnosticadas de amenaza de parto prematuro y en tratamiento con ritodrina. Nuestros resultados indican que se consiguió detener el parto en todos los casos; sin embargo, ninguna paciente estuvo exenta de sufrir efectos adversos cuando la administración se realizó por vía intravenosa, observándose con mayor frecuencia taquicardia materna y fetal. Concluimos con la necesidad de monitorizar a las pacientes y prestar cuidados de enfermería para evitar las complicaciones derivadas de la administración a fin de conseguir una medicación más inocua y con menos riesgos (AU)