An overview of air pollution research in Chile: Bibliometric analysis and scoping review, challenger and future directions.

This study provides a comprehensive overview and bibliometric analysis of air pollution research in Chile from 1980 to 2022. The analysis reveals a significant increase in scientific production, a 9.2 annual growth rate, and an H-index of 60. The research spans 33 countries and is influenced by environmental sciences, meteorology, and atmospheric sciences journals. The top ten authors account for 33.49 % of all publications, with local institutions contributing more than 35 %. The University of Chile and the Pontifical Catholic University of Chile are significant contributors. The most cited articles focus on health impacts and various pollutant sources, emphasizing air pollution as a critical public health concern. The study also emphasizes environmental science, meteorology, and atmospheric science, focusing on topics such as air pollution and health, pollutants, models, sources and chemistry, and social sciences. The findings are affirmed through rigorous discussion and review, providing a roadmap for future research, guiding decision-making processes, and expanding the knowledge frontier in the field.

The oxidative potential of airborne particulate matter in two urban areas of Chile: More than meets the eye.

Oxidative potential (OP) has gained attention as a parameter that can reveal the ability of different properties of particulate matter (PM) to generate reactive oxygen species (ROS) as one single value. Moreover, OP is also believed to be a predictor of toxicity and hence the health effects of PM. This study evaluated the OP of PM10, PM2.5,and PM1.0samples using dithiothreitol assays in two cities of Chile (Santiago and Chillán). The results showed that the OP was different between cities, PM size fractions, and seasons. Additionally, OP was strongly correlated with certain metals and meteorological variables. Higher mass-normalized OP was observed during cold periods in Chillán and warm periods in Santiago and was associated with PM2.5 and PM1. On the other hand, volume-normalized OP was higher during winter in both cities and for PM10. Additionally, we compared the OP values to the Air Quality Index (AQI) scale and found cases of days that were classified as having "good" air quality (supposed to be less harmful to health) showing extremely high OP values that were similar to those on days that were classified as "unhealthy". Based on these results,we suggest using the OP as a complementary measure to the PM mass concentration because it includes important new information related to PM properties and compositions that could help improvecurrent air quality management tools.

Cáncer colorrectal ­ diagnóstico y tratamiento: revisión bibliográfica / Colorectal cancer ­ diagnosis and treatment: literature review

Colorectal cancer (CRC) is the third most prevalent cancer worldwide. Although improvements in detection and treatment have been implemented; CRC incidence, prevalence, and mortality remain high, even in developed countries. The risk of developing this cancer is related to poor eating habits, smoking, inflammatory bowel disease, polyps, genetic factors, and aging. There are several methods for detecting colorectal cancer, including the guaiac test, stool immunochemical test, stool DNA test, sigmoidoscopy, colonoscopy, and barium enema. The stage at which the cancer is detected determines the patient's prognosis, survival, and treatment. Treatments include endoscopic and surgical local excision, preoperative radiation therapy and systemic downstage therapy, extensive surgery for locoregional and metastatic disease, local ablative therapies for metastases, and palliative, targeted chemotherapy and immunotherapy.

El cáncer colorrectal (CCR) es el tercer cáncer más prevalente a nivel mundial. A pesar de que se han implementado mejoras en la detección y el tratamiento; la incidencia, la prevalencia y la mortalidad del CCR siguen siendo altas, incluso en países desarrollados. El riesgo de desarrollar este cáncer está relacionado con malos hábitos alimentarios, tabaquismo, enfermedad inflamatoria intestinal, pólipos, factores genéticos y envejecimiento. Existen varios métodos para detectar el cáncer colorrectal, como la prueba de guayaco, la prueba inmunoquímica de heces, la prueba de ADN en heces, la sigmoidoscopia, la colonoscopia y el enema de bario. El estadio en el que se detecta el cáncer determina el pronóstico, la supervivencia y el tratamiento del paciente. Los tratamientos incluyen escisión local endoscópica y quirúrgica, radioterapia preoperatoria y terapia sistémica de reducción del estadio, cirugía extensa para enfermedad locorregional y metastásica, terapias ablativas locales para metástasis y quimioterapia paliativa, terapia dirigida e inmunoterapia.

Ammonia recovery from acidogenic fermentation effluents using a gas-permeable membrane contactor.

A gas-permeable membrane (GPM) contactor was used to recover ammoniacal nitrogen from a synthetic and a biowaste fermentation broth under different pH (from 6 to 11) and temperatures (35 and 55 °C). Ammonia mass transfer constant (Km) increased as pH and temperature increased. For synthetic broth, pH 10 provided the best results, when considering the Km (9.2·10-7 m·s-1) and the reagents consumption (1.0 mol NaOH·mol-1 TAN and 0.6 mol H2SO4·mol-1 TAN). Biowaste fermentation generated a broth with a high concentration of ammoniacal nitrogen (4.9 g N·L-1) and volatile fatty acids (VFA) (41.1 g COD·L-1). Experiments using the biowaste broth showed a lower Km (5.0·10-7 m·s-1 at pH 10) than the synthetic broth, related to the solution matrix and other species interference. VFAs were not detected in the trapping solution. Overall, these results show that GPM is a suitable technology to efficiently separate ammoniacal nitrogen and VFA from fermentation broths.

Influence of surface morphology and internal structure on the mechanical properties and tribological response of Boa Red Tail and Python Regius snake skin.

The understanding of the tribological behavior of natural structures has been used as inspiration to design and optimize surfaces for diverse applications in engineering. In the present work, morphological, microstructural, mechanical and tribological characterization of the shed skin of two snake species, namely Boa Red Tail and Python Regius was carried out. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) analyses showed the existence of deterministic patterns, i.e., ordered arrays of geometrical features at the surface, while Transmission Electron Microscopy (TEM) allowed studying the internal structure and chemical composition of the skin sheds. Nanoindentation measurements showed significant variations in hardness and elastic modulus from the surface to the inner layers of the skin, and pin-on-disc tests revealed anisotropic behavior of the friction coefficient (COF) as a function of the sliding direction against balsa wood in dry conditions. Correlations between the friction data, nano-indentation mechanical properties and subsurface skin structure were established for both species taking into account the ways in which the skins' deterministic patterns influence the tribological performance.

Air pollution and COVID-19 lockdown in a large South American city: Santiago Metropolitan Area, Chile.

The implementation of confinement and physical distancing measures to restrict people's activities and transit in the midst of the COVID-19 pandemic allowed us to study how these measures affect the air quality in urban areas with high pollution rates, such as Santiago, Chile. A comparative study between the concentrations of PM10, PM2.5, NOx, CO, and O3 during the months of March to May 2020 and the corresponding concentrations during the same period in 2017-2019 is presented. A combination of surface measurements from the air quality monitoring network of the city, remote satellite measurements, and simulations of traffic activity and road transport emissions allowed us to quantify the change in the average concentrations of each pollutant. Average relative changes of traffic emissions (between 61% and 68%) implied statistically significant concentrations reductions of 54%, 13%, and 11% for NOx, CO, and PM2.5, respectively, during the pandemic period compared to historical period. In contrast, the average concentration of O3 increased by 63% during 2020 compared to 2017-2019. The nonlinear response observed in the pollution levels can be attributed to the changes in the vehicular emission patterns during the pandemic and to the role of other sources such as residential emissions or secondary PM.

Dithiothreitol-based oxidative potential for airborne particulate matter: an estimation of the associated uncertainty.

Oxidative stress is considered as one of the main mechanisms by which airborne particles produce adverse health effects. Several methods to estimate the oxidative potential (OP) of particulate matter (PM) have been proposed. Among them, the dithiothreitol (DTT) assay has gained popularity due to its simplicity and overall low implementation cost. Usually, the estimations of OPDTT are based on n-replicates of a set of samples and their associated standard deviation. However, interlaboratory comparisons of OPDTT can be difficult and lead to misinterpretations. This work presents an estimation of the total uncertainty for the OPDTT measurement of PM10 and PM2.5 samples collected in Santiago (Chile), based on recommendations by the Joint Committee for Guides in Metrology and Eurachem. The expanded uncertainty expressed as a percentage of the mass-normalized OPDTT measurements was 18.0% and 16.3% for PM10 and PM2.5 samples respectively. The dominating contributor to the total uncertainty was identified (i.e., DTT consumption rate, related to the regression and repeatability of experimental data), while the volumetric operations (i.e., pipettes) were also important. The results showed that, although the OP measured following the DTT assay has been successfully used to estimate the potential health impacts of airborne PM, uncertainty estimations must be considered before interpreting the results.

Utilidad de mediciones objetivas para la programación en implantes cocleares / Use of objective measures for cochlear implant programming

RESUMEN Introducción: La programación adecuada de los implantes cocleares permiten lograr niveles de estimulación auditivos óptimos. Se realiza de forma individualizada, siendo la detección del umbral de confort ideal un desafío. Se ha descrito la utilidad de los potenciales auditivos del tronco encefálico eléctrico (ePEATC) y el reflejo eléctrico estapedial (eREE) para este propósito. Objetivo: Determinar la posibilidad de realizar ePEATC y eREE en pacientes adultos y pediátricos con implantes cocleares, y evaluar cambios en la programación de los implantes cocleares luego de las mediciones objetivas. Material y método: Se realizó un estudio prospectivo, descriptivo, de pacientes con implante coclear marca MED-EL®, separando los pacientes en dos grupos: el grupo adulto (n =5) y el grupo pediátrico (n =5). Todos los pacientes incluidos presentaron más de 6 meses de encendido del implante. Se evaluaron variables epidemiológicas y tiempo de encendido del implante. Se realizó una otoscopía, prueba básica de funcionamiento del implante, y las mediciones objetivas eléctricas (ePEATC, eREE). Con estos resultados se ajustó el umbral de confort. Resultados: El tiempo promedio de encendido del implante en el grupo adulto fue de 27 meses, y 30 meses en el grupo pediátrico. El ePEATC requiere más tiempo y cooperación al compararlo con eREE. Luego de estas evaluaciones objetivas, fue necesario el ajuste del umbral de confort en tres pacientes adultos, y en dos pacientes pediátricos. Fue necesario realizar una audiometría de campo libre para estimar el umbral de confort en dos pacientes pediátricos que no presentaron respuesta en eREE. Conclusión: Fue posible realizar estas mediciones objetivas en pacientes adultos y pediátricos, siendo mejor tolerado y requiriendo menos tiempo, el eREE.

ABSTRACT Introduction: Mapping a cochlear implant allows for adjusting ideal electrical stimulation limits. It is an individualized process and detecting the most comfortable loudness level can be challenging. The use of electrically evoked auditory brainstem response (ePEATC) and electrically evoked stapedius reflex thresholds (eREE) have been considered for this purpose. Aim: To determine the feasibility of performing ePEATC and eREE on adult and pediatric patients with a cochlear implant, and to evaluate changes in programming following these objective measures. Material and method: A prospective, descriptive study was completed, of patients with MED-EL® cochlear implants, separating patients into two groups: adults (n=5) and children (n=5). All of the patients included had their implants activated for 6 months or longer. Epidemiological variables and duration of implant activation were evaluated. Otoscopy, a basic implant functioning evaluation, and objective measures (ePEATC, eREE) were performed. With these results, comfortable loudness levels were adjusted. Results: Average duration of implant activation was 27 months and 30 months, for adults and children respectively. Performing ePEATC required more time and cooperation as compared to eREE. Following the objective measures, adjustment of the comfortable loudness levels was required for three adult and two pediatric patients. Sound field audiometry was necessary for two pediatric patients in order to estimate the comfortable loudness levels because the eREE responses were absent. Conclusions: It is feasible to perform these objective measures for both adult and pediatric patients, with eREE requiring less time and being better tolerated by patients.

An extremely rare case of an oversized accessory spleen: case report and review of the literature.

BACKGROUND: The accessory spleen is a congenital defect characterized by a separated ectopic splenic parenchyma. The size is rarely more than 4 cm. The preoperative diagnosis is prohibitive preoperatively. The aims of the present manuscript were to present the case of a patient with a rare oversize accessory spleen and a review of the literature. CASE PRESENTATION: A 15-year-old boy was admitted to the emergency department following blunt abdominal trauma. The computed tomographic scan showed a traumatic rupture of the spleen and a 7-cm mass at the left side of the retroperitoneal space. Conservative treatment started and aborted after 4 h due to the onset of haemodynamic instability. Splenectomy was performed. An accessory spleen was discovered. A second large mass in the retroperitoneum was diagnosed as a second large accessory spleen that was also left in place. The postoperative course was uneventful, and the patient was discharged on the 7th postoperative day. Seven months later, the CT scan showed viability of both accessory spleens. CONCLUSION: An accessory spleen can be variously located and the retroperitoneal position is extremely uncommon. Preoperative diagnosis is still difficult, especially in emergency and as in our case, the literature shows the difficulty of reaching a diagnosis before surgery. The main misdiagnosis is neoplastic disease and for this reason accessory spleen can be wrongly removed. An undiagnosed pre or intra operative retroperitoneal mass, closely to the spleen, have to be managed carefully. The diagnosis of accessory spleen needs to be ever considered as if found, represents a great possibility to conduct a normal life after splenectomy (of main spleen) for trauma.

Open conversion for laparoscopically difficult cholecystectomy is still a valid solution with unsolved aspects.

The difficult laparoscopic cholecystectomy remains a surgical challenge for surgeons who must decide between laparoscopic continuation and open conversion. The balance between the lack of open surgery training of young surgeons and the risk of maintaining the laparoscopic approach in difficult laparoscopic cholecystectomy is still an unresolved problem. Furthermore, the time that must be spent in an attempt to complete laparoscopic surgery before conversion is still controversial. The authors in this letter discuss about these and other questions that still require an answer.

Exploring atmospheric stagnation during a severe particulate matter air pollution episode over complex terrain in Santiago, Chile.

A severe air quality degradation event occurred in the Santiago Metropolitan Area (SMA), Chile, in June 2014. Meteorological and air quality measurements from 11 stations in the area as well as numerical simulations using the Weather and Research Forecasting (WRF) model were used to explain the main reasons for the occurrence of elevated particulate matter (PM) concentrations. The conditions were characterized with formation of a coastal low in central Chile between the southeastern anticyclone and a high-pressure system over Argentina. At a local scale, these conditions generated a depression at the base of the inversion layer, an increase in the vertical thermal stability, lower humidity and low-wind conditions, which were conducive to a decrease in pollutant dispersion and insufficient ventilation of the polluted air. Measurements and simulations using the WRF model revealed a vertical structure of the boundary layer during these stagnant conditions and provided a basis for a trajectory analysis. The back-trajectory calculation showed that the transport of air parcels was contained in the valley during the highest concentrations. The analysis also enabled the definition of the threshold values of a simple indicator of air pollution (ventilation coefficient, VC), which confirmed the evolution of the episode and divided the observed daily concentrations into two groups, with one including values above the limits prescribed by the national air quality standards (NAQS) and the other including values below these limits. For the SMA, the daily PM concentrations above the NASQ limits were associated with an overall mean threshold value of VC below 500 m2 s-1 (for PM2.5) and 300 m2 s-1 (for PM10). To apply the VC analysis to other pollutants and different geographic locations, different threshold values should be evaluated.

A new modified Mayo technique: should the surgeons need a new open technique for hernia repair in their armamentarium?

INTRODUCTION: The Mayo technique is one of the most common techniques used to repair incisional, umbilical, and epigastric hernias. A high percentage of recurrences, together with the use of particular expensive types of meshes, are some of the most relevant problems in this surgical field. PATIENTS AND METHODS: This study is a clinical prospective observational and involves all the patients who underwent procedures using a new modified Mayo technique from 2006 through 2013. The general criteria analyzed were age, sex, obesity, smoke abuse, diabetes, chronic diseases, type of hernia, operative time, morbidity and mortality. All the patients involved in this study were followed-up from 6 to 120 months. RESULTS: The types of hernia were 5 epigastic hernia (20,8%), 8 umbilical hernia (33,3%), 11 midline incision hernia (45,9%). Ten patients (41,7%) presented non-complicated hernias; 8 patients (33,3%) presented strangulated hernias and 6 patients (25,0%) presented obstructed hernias. No intestinal resection was necessary in any of the patients. The mean operative time was 55 minutes (range 30-180). The mean hospital stay of the patients' after-post operative procedure was 4.5 days (range, 2 to 8 days). No major complications have been reported. Only one patient present a recurrence. CONCLUSION: These preliminary results suggest that this modified Mayo technique could be useful in the armamentarium of surgeon to repair incisional, umbilical, and epigastric hernias. More studies are needed to validate the technique.

Endocannabinoids participate in placental apoptosis induced by hypoxia inducible factor-1.

During pregnancy, apoptosis is a physiological event critical in the remodeling and aging of the placenta. Increasing evidence has pointed towards the relevance of endocannabinoids (ECs) and hypoxia as modulators of trophoblast cell death. However, the relation between these factors is still unknown. In this report, we evaluated the participation of ECs in placental apoptosis induced by cobalt chloride (CoCl2), a hypoxia mimicking agent that stabilizes the expression of hypoxia inducible factor-1 alpha (HIF-1α). We found that HIF-1α stabilization decreased FAAH mRNA and protein levels, suggesting an increase in ECs tone. Additionally, CoCl2 incubation and Met-AEA treatment reduced cell viability and increased TUNEL-positive staining in syncytiotrophoblast layer. Immunohistochemical analysis demonstrated Bax and Bcl-2 protein expression in the cytoplasm of syncytiotrophoblast. Finally, HIF-1α stabilization produced an increase in Bax/Bcl-2 ratio, activation of caspase 3 and PARP cleavage. All these changes in apoptotic parameters were reversed with AM251, a CB1 antagonist. These results demonstrate that HIF-1α may induce apoptosis in human placenta via intrinsic pathway by a mechanism that involves activation of CB1 receptor suggesting a role of the ECs in this process.

Starch gelatinization and in vitro digestibility behaviour after heat treatment: Comparison between plantain paste and piece of pulp.

Over the 65-100°C range and at a water content of 1.6kgkg(-1)db, a comparison was conducted between plantain paste (dispersion made of flour and water) and pulp pieces after cooking to evaluate their respective degree of starch gelatinization (α) and in vitro digestibility. Below 76°C and at 100°C, the gelatinization behaviour of starch into pulp pieces and paste was similar, whereas at 85°C a significant mean relative difference was observed in between. For α in the 0-1 range, pieces of plantain pulp exhibited a lower rapidly digestible starch fraction (30%) and a higher resistant starch fraction (33%) than the flour paste, suggesting some structural effects. Both Weibull and exponential models showed a good fit for α over temperature range and starch digestibility fractions over α. Although no explicit relationship was established between the intact pulp structure and grinded flour state of plantain, the evaluation of the degree of starch gelatinization and digestibility of a plantain flour paste, could be used to predict the gelatinization and digestibility behaviour of plantain starch in entire pieces of pulp.

Modified Mayo Technique for Ventral Hernia Repair: An Experimental Study.

BACKGROUND: To reduce the rate of recurrence of incisional hernia repair associated with open anatomic techniques, we present an experimental study, focusing on two different sutures, with the aim to apply clinically in a revised version of the Mayo technique. METHODS: Thirteen biological tissue samples from adult pig central brawn and upper and lower fasciae were measured using two techniques defined as "œunbroken suture thread" and "œseparated suture stitches" to test the breaking resistance of the two types of suture. RESULTS: The t test results show that the two sets can be considered as different populations. The mean tensile stress ƒmax is greater (with reduced deviation) for the specimens of the set sutured with unbroken thread technique. Student'™s t-test performed on values obtained for each set of samples indicated that the unbroken thread suture technique corresponds to higher ultimate failure strength. CONCLUSION: Considering these results, a modified Mayo technique with continuous closure could be suggested. Of course a valid clinical study is required to better clarify this experimental hypothesis.

Anemia as One of Presenting Symptoms in an Adult with Cyst and Torsion of the Omentum - A Case Report.

BACKGROUND: Torsion is an uncommon disorder of the omentum and cysts are one of the rarest causes of omental torsion. To our knowledge, this is the first report of a case of an omental cyst presenting with both omental torsion and anemia. CASE PRESENTATION: We herein present a case report of a 41 year old indian female patient who presented with anemia (hemoglobin concentration 6.5 g/dL) and intermittent abdominal pain caused by torsion of a hemorrhagic omental cyst. A computed tomography scan, showed an omental cyst with free fluid in the abdominal cavity. At abdominal exploration, 1.5 L of hemorrhagic fluid was confirmed in the abdominal cavity. The cyst and twisted omentum were removed en bloc. The patient had an uneventful postoperative course and was discharged on day 8. At her 2-month follow-up, she was no longer anemic (hemoglobin concentration 10.7 g/dL). CONCLUSION: Cases of anemia associated with omental torsion have been reported in children; however, to the best of our knowledge, this is the first reported case of such a presentation in an adult. In such patients, surgical removal is the treatment of choice. Persons with recurrent abdominal pain and anemia must be assessed carefully and their differential diagnosis should include omental torsion. Appropriate diagnosis and treatment help avoid complications.

Trends and threshold exceedances analysis of airborne pollen concentrations in Metropolitan Santiago Chile.

Pollen is one of the primary causes of allergic rhinoconjunctivitis in urban centers. In the present study, the concentrations of 39 different pollens in the Santiago de Chile metropolitan area over the period 2009-2013 are characterized. The pollen was monitored daily using Burkard volumetric equipment. The contribution of each type of pollen and the corresponding time trends are evaluated. The concentrations of the pollens are compared with the established threshold levels for the protection of human health. The results show that the total amount of pollen grains originating from trees, grasses, weeds and indeterminate sources throughout the period of the study was 258,496 grains m-3, with an annual average of 51,699 ± 3,906 grains m-3 year-1. The primary source of pollen is Platanus orientalis, which produces 61.8% of the analyzed pollen. Grass pollen is the third primary component of the analyzed pollen, with a contribution of 5.82%. Among the weeds, the presence of Urticacea (3.74%) is remarkable. The pollination pattern of the trees is monophasic, and the grasses have a biphasic pattern. The trends indicate that the total pollen and tree pollen do not present a time trend that is statistically significant throughout the period of the study, whereas the grass pollen and weed pollen concentrations in the environment present a statistically significant decreasing trend. The cause of this decrease is unclear. The pollen load has doubled over the past decade. When the observed concentrations of the pollens were compared with the corresponding threshold levels, the results indicated that over the period of the study, the pollen concentrations were at moderate, high and very high levels for an average of 293 days per year. Systematic counts of the pollen grains are an essential method for diagnosing and treating patients with pollinosis and for developing forestation and urban planning strategies.

Accuracy and reliability of Chile's National Air Quality Information System for measuring particulate matter: Beta attenuation monitoring issue.

A critical analysis of Chile's National Air Quality Information System (NAQIS) is presented, focusing on particulate matter (PM) measurement. This paper examines the complexity, availability and reliability of monitoring station information, the implementation of control systems, the quality assurance protocols of the monitoring station data and the reliability of the measurement systems in areas highly polluted by particulate matter. From information available on the NAQIS website, it is possible to confirm that the PM2.5 (PM10) data available on the site correspond to 30.8% (69.2%) of the total information available from the monitoring stations. There is a lack of information regarding the measurement systems used to quantify air pollutants, most of the available data registers contain gaps, almost all of the information is categorized as "preliminary information" and neither standard operating procedures (operational and validation) nor assurance audits or quality control of the measurements are reported. In contrast, events that cause saturation of the monitoring detectors located in northern and southern Chile have been observed using beta attenuation monitoring. In these cases, it can only be concluded that the PM content is equal to or greater than the saturation concentration registered by the monitors and that the air quality indexes obtained from these measurements are underestimated. This occurrence has been observed in 12 (20) public and private stations where PM2.5 (PM10) is measured. The shortcomings of the NAQIS data have important repercussions for the conclusions obtained from the data and for how the data are used. However, these issues represent opportunities for improving the system to widen its use, incorporate comparison protocols between equipment, install new stations and standardize the control system and quality assurance.