Factores asociados a la depresión, ansiedad y estrés de los trabajadores del sector publico de salud de La Plata y Gran La Plata al inicio de la pandemia por Covid-19 / Factors associated with depression, anxiety and stress of workers in the public health sector of La Plata and Greater La Plata at the beginning of the Covid-19 pandemic

La pandemia por COVID-19 expuso a los trabajadores de salud a una enorme exigencia y presión en su labor cotidiana. Objetivo: Evaluar el nivel de depresión, ansiedad y estrés en trabajadores de salud durante la pandemia por COVID-19 y su asociación con características personales, laborales,sentimientos, experiencias y conductas relacionadas a la pandemia. Materiales y métodos: Estudio analítico de corte transversal. Durante el mes de junio del 2020 se enviaron formularios vía e-mail y redes sociales a trabajadores de la salud del sector público de La Plata y Gran La Plata. Se evaluó el nivel de depresión, ansiedad, y estrés mediante el cuestionario DASS-21. Se relevaron variables personales, laborales, sentimientos, experiencias y conductas vinculados a la pandemia. Se analizó la asociación entre las características de los trabajadores y la presencia de síntomas psicológicos mencionados. Resultados: Participaron 515 trabajadores, 41 años (33;50), 83,3% femenino. El síntoma psicológico más frecuente fue el estrés (58,2 %), seguido por ansiedad (33,1%) y depresión (24,7%). Se hallaron mayores chances de presentar estos síntomas en trabajadores que percibieron sentimientos, experiencias y conductas negativas vinculados a la pandemia. Los trabajadores de enfermería y administración, y aquellos que convivían con personas de riesgo tuvieron mayores chances de presentar ansiedad. Conclusión: Los trabajadores de salud de La Plata y Gran La Plata presentaron diversos grados de depresión, ansiedad y estrés que se asocian a sentimientos negativos relacionados con la pandemia

The COVID-19 pandemic exposed health workers to enormous demands and pressure in their daily work. Objective: To evaluate the level of anxiety, depression and stress in health workers during the COVID-19 pandemic and its association with personal and work characteristics, feelings, experiences, and behaviors related to the pandemic. Materials and methods: Cross-sectional analytical study. During the month of June 2020, forms were sent via e-mail and social networks to health workers in the public sector of La Plata and Gran La Plata. The level of depression, anxiety, and stress was evaluated using the DASS-21 questionnaire. Personal and work variables, feelings, experiences and behaviors linked to the pandemic were surveyed. The association between the characteristics of the workers and the presence of the aforementioned psychological symptoms was analyzed. Results: 515 workers participated, 41 years old (33;50), 83.3% female. The most frequent psychological symptom was stress (58.2%), followed by anxiety (33.1%) and depression (24.7%). Greater chances of presenting these symptoms were found in workers who perceived negative feelings, experiences and behaviors linked to the pandemic. Nursing and administration workers, and those who lived with people at risk had a higher chance of presenting anxiety. Conclusion: Health workers from La Plata and Gran La Plata presented varying degrees of depression, anxiety, and stress that are associated with negative feelings related to the pandemic

Características Gineco-Obstétricas, Nutricionales y Clínico- Metabólicas de Mujeres durante el Posparto asistidas en un Hospital Publico / Gyneco-Obstetric, Nutritional and Clinical-Metabolic Characteristics of Postpartum Women Assisted in a Public Hospital

Introducción: El puerperio es una etapa determinante para la mujer, sin embargo la atención está focalizada en el recién nacido. Objetivo: Describir las características gineco-obstétricas, nutricionales y clínico-metabólicas de mujeres durante el posparto que asisten al consultorio materno del Instituto de Desarrollo e Investigaciones Pediátricas. Población y Métodos: Se realizó un análisis retrospectivo de las historias clínicas de mujeres que realizaron su primer control entre los 3 y 6 meses posparto en un consultorio materno de un hospital público entre junio 2018 y diciembre 2019. Se analizaron variables sociodemográficas, gineco-obstétricas, nutricionales y clínico-metabólicas. Resultados: Participaron 211 mujeres, edad 26 (21; 31) años, 41,7 % oriundas de países limítrofes. 38,8 % tuvo un embarazo durante la adolescencia, 38,7 % de los partos fue por cesárea y 21,3 % refirió antecedentes de aborto Más de la mitad presentaron sobrepeso-obesidad y alteraciones del perfil lipídico Conclusiones: Las mujeres asistidas durante el postparto en un hospital público presentan alta frecuencia de exceso de peso y alteraciones metabólicas así como historial de cesáreas y embarazo adolescente. El conocimiento de las problemáticas más prevalentes es clave para el diseño de estrategias de prevención e intervenciones oportunas

Introduction: The puerperium is a determining stage for women, however, attention is focused on the newborn. Objective: To describe the gyneco-obstetric, nutritional and clinical-metabolic characteristics of postpartum women who attend the IDIP maternal clinic. Population and methods: A retrospective analysis was carried out of the medical records of women who underwent their first check-up between 3 and 6 months postpartum in a maternal clinic of a public hospital between June 2018 and December 2019 Sociodemographic, gynecological, nutritional, and clinical-metabolic variables were analysed. Results: 211 women participated, age 26 (21; 31) years old, 41.7% from neighbouring countries, 38.8% had a pregnancy during adolescence, 38.7% of deliveries were by caesarean section, and 21.3% reported a history of abortion. More than half presented overweight-obesity and lipid profile alterations. Conclusions: The women assisted during the postpartum in a public hospital present a high frequency of excess weight and metabolic alterations as well as a history of caesarean sections and adolescent pregnancy. Knowledge of the most prevalent problems is key for the design of prevention strategies and timely interventions

Supplementation with Phaseolus vulgaris Leaves Improves Metabolic Alterations Induced by High-Fat/Fructose Diet in Rats Under Time-Restricted Feeding.

Time-restricted feeding and food enriched in polyphenols are strategies to prevent or reduce metabolic disorders. Bean leaves (Phaseolus vulgaris L.) are a recognized source of polyphenolic compounds, whose effects on metabolic pathways are not well studied. We evaluated the combined effects of dietary supplementation with Phaseolus vulgaris leaves (10% w/w) (BL) and a 7-h daytime-restricted feeding protocol (RF) under a hypercaloric diet (high fat + high fructose) (HFFD) on the metabolic parameters related to glucose and lipid handling. Adult male Wistar rats were treated for 8 weeks with standard and HFFD diets with or without BL. The results showed that RF improved metabolic alterations induced by HFFD (e.g., hepatic steatosis, increased triacylglycerols, and serum lipoproteins). Supplementation with BL significantly enhanced this effect and downregulated the mRNA expression of carbohydrate and lipid metabolism genes in the liver. These results indicate that dietary supplementation with BL enhances the benefits elicited by RF.

Prolactin selectively inhibits the LPS-induced chemokine secretion of human foetal membranes.

Background: Inflammation is a condition that jeopardizes the continuity of pregnancy because it increases the secretion of chemokines that favor the migration of leukocytes from maternal and fetal circulations to the cervix, placenta, and the chorioamniotic membranes. During pregnancy, the level of prolactin (PRL) in the amniotic fluid is high; there is evidence to suggest that PRL contributes to maintain a privileged immune environment in the amniotic cavity. We test the effect of prolactin on the secretion profile of chemokines in human fetal membranes.Methods: Nine fetal membranes collected from healthy nonlabouring cesarean deliveries at term. We placed whole membrane explants in a two-chamber culture system. Choriodecidua and amniotic chambers were pretreated with 250, 500, 1000, or 4000 ng/ml of PRL for 24 h, then choriodecidua was cotreated with 500 ng/ml of lipopolysaccharide (LPS) and PRL for 24 h. We used ELISA to measure secreted levels of four chemokines (RANTES, monocyte chemoattractant protein 1 (MCP-1), MIP-1α, and IL-8) in both amnion and choriodecidua regions.Results: In comparison with basal conditions, LPS treatment induced significantly higher secretion of RANTES, MCP-1, and MIP-1α, but not of IL-8. RANTES was mainly produced by choriodecidua and cotreatment with PRL significantly decreased its LPS-induced secretion. MCP-1 was primarily produced by the amnion and its secretion was only inhibited by 4000 ng/ml of PRL. Both membrane regions produced MIP-1α, which was significantly inhibited at 1000 and 4000 ng/ml PRL concentrations. IL-8 showed no significant changes regardless of PRL concentration.Conclusion: PRL inhibits the differential secretion of proinflammatory chemokines by human fetal membranes.

Association between heavy metals and metalloids in topsoil and mental health in the adult population of Spain.

BACKGROUND AND OBJECTIVES: Despite the biological plausibility of the association between heavy metal exposure and mental health disorders, epidemiological evidence remains scarce. The objective was to estimate the association between heavy metals and metalloids in soil and the prevalence of mental disorders in the adult population of Spain. METHODS: Individual data came from the Spanish National Health Survey 2011-2012, 18,073 individuals residing in 1772 census sections. Mental health was measured with the 12-item General Health Questionnaire. The concentration estimates of heavy metal and metalloid levels in topsoil (upper soil horizon) came from the Geochemical Atlas of Spain based on 13,317 soil samples. Levels of lead (Pb), arsenic (As), cadmium (Cd) and manganese (Mn) were estimated in each census section by "ordinary Kriging". Odds ratios (OR) were calculated by multilevel logistic regression models. RESULTS: Compared with the lowest Pb concentration levels quartile, the OR for the second quartile was 1.29 (95%CI: 1.11-1.50), increasing progressively to 1.37 (95%CI: 1.17-1.60) and 1.51 (95%CI: 1.27-1.79) in the third and fourth quartiles, respectively. For As, the association was observed in the third and fourth quartiles: 1.21 (95%CI: 1.04-1.41) and 1.42 (95% CI: 1.21-1.65), respectively. Cd was associated also following a gradient from the second quartile: 1.34 (95%CI: 1.15-1.57) through the fourth: 1.84 (95%CI: 1.56-2.15). In contrast, Mn only showed a positive association at the second quartile. Additionally, individuals consuming vegetables > once a day the OR for the fourth quartile of Pb concentration, vs. the first, increased to 2.93 (95%CI: 1.97-4.36); similarly for As: 3.00 (95%CI: 2.08-4.31), and for Cd: 3.49 (95%CI: 2.33-5.22). CONCLUSIONS: Living in areas with a higher concentration of heavy metals and metalloids in soil was associated with an increased probability of having a mental disorder. These relationships were strengthened in individuals reporting consuming vegetables > once a day.

The Multigaussian method: a new approach to mitigating spatial heterogeneities with multichannel radiochromic film dosimetry.

The main objective of multichannel radiochromic film dosimetry methods is to correct, or at least mitigate, spatial heterogeneities in the film-scanner response, especially variations in the active layer thickness. To this end, films can also be scanned prior to irradiation. In this study, the abilities of various single channel and multichannel methods to reduce spatial heterogeneities, with and without scanning before irradiation, were tested. Red, green and blue single channel models, two additive channel independent perturbation (CHIP) models and two multiplicative CHIP models were compared with the Multigaussian method. The Multigaussian method is a new approach to multichannel dosimetry, based on experimental findings. It assumes that the probability density function of the response vector formed by the pixel values of the different color channels, including irradiated and non-irradiated scans, follows a multivariate Gaussian distribution. The Multigaussian method provided more accurate doses than the other models under comparison, especially when incorporating the information of the film prior to irradiation. The relative dose differences between reference doses measured with MatriXX and film doses were examined. After applying inter-scan and lateral corrections, the lowest mean absolute errors were 0.8% and 1.0% for the Multigaussian method with and without the information of the scan before irradiation, respectively. Followed by the uniform multiplicative CHIP and red single channel models, using pixel values and net optical density, respectively, both with 1.1%.

Evaluation of the Myo armband for the classification of hand motions.

Pattern recognition-based control systems have been widely investigated in prostheses and virtual reality environments to improve amputees' quality of life. Most of these systems use surface electromyography (EMG) to detect user movement intentions. The Myo armband (MYB) is a wireless wearable device, developed by Thalmic Labs, which enables EMG recordings with a limited bandwidth (<100Hz). The aim of this study was to compare MYB's narrow bandwidth with a conventional EMG acquisition system (CONV) that captures the full EMG spectrum to assess its suitability for pattern recognition control. A crossover study was carried out with eight able-bodied participants, performing nine hand gestures. Six features were extracted from the data and classified by Linear Discriminant Analysis (LDA). Results showed a mean classification error of 5.82 ± 3.63% for CONV and 9.86 ± 8.05% for MYB with no significantly difference (P = 0.056). This implies that MYB may be suitable for pattern recognition applications despite the limitation in the bandwidth.

The use of technology to improve health care to Saskatchewan's First Nations communities.

BACKGROUND: Saskatchewan is a province of over one million people and over 13% are Indigenous peoples, many of whom live on reserve lands. Despite continued efforts, access to health care remains a significant challenge for these Indigenous people, especially those in the North. OBJECTIVE: To address this challenge, Saskatchewan's health care providers have been incorporating the use of technology for various health services. This paper describes various ways technology has been used in First Nations communities in Saskatchewan. METHODS: Several pilot projects between First Nations leaders and health care providers, in the communities as well as in the urban setting, have taken place over the past 10 years. Information on these pilots was supplemented with literature reviews and consultations with colleagues at the Northern Inter-Tribal Health Authority, the First Nations and Inuit Health Branch (FNIHB), Health Canada and lead physicians for services to the North. RESULTS: Numerous technologies have shown promise in aiding the timely delivery of high quality health care. Remote Presence Robotic Technology (RPRT) is a form of telemedicine that creates the sense that a clinician is at the patient's side; enabling clinical services to be provided remotely and in real time. Increasing access to internet services and providing computer tablets to community health nurses have improved patients' access to clinical care and to vital health care information. Robotic ultrasonography has been used to provide onsite care for pre-natal patients. The provision of cell phones to HIV-positive patients has improved compliance with anti-retroviral therapy and has resulted in better clinical outcomes. The Xpert MTB/RIF (Mycobacerium tuberculosis complex / resistance to rifampicin) is an automated device that, through analysis of raw sputum samples, can identify the presence of M. tuberculosis with greater speed, sensitivity and specificity than the conventional acid-fast bacilli (AFB) smear. Similarly, telemedicine remote communications equipment is being used for patient care across communities. Panorama is a comprehensive, integrated public health information system designed for public health professionals and is currently being introduced in 21 communities in Saskatchewan. CONCLUSION: Not only do these innovative technologies appear to improve access and enhance the quality of timely care in remote communities but they also bring comfort to patients, prevent unnecessary transportation and minimize time away from work and family. Although these technologies are not a panacea for some of the determinants of health that can affect the incidence and severity of infectious diseases in First Nations, they do appear to address some of the geographic challenges faced in providing health services in remote communities.

Development and psychometric properties of the Suicidality: Treatment Occurring in Paediatrics (STOP) Suicidality Assessment Scale (STOP-SAS) in children and adolescents.

BACKGROUND: To create a self-reported, internet-based questionnaire for the assessment of suicide risk in children and adolescents. METHODS: As part of the EU project 'Suicidality: Treatment Occurring in Paediatrics' (STOP project), we developed web-based Patient Reported Outcome Measures (PROMs) for children and adolescents and for proxy reports by parents and clinicians in order to assess suicidality. Based on a literature review, expert panels and focus groups of patients, we developed the items of the STOP Suicidality Assessment Scale (STOP-SAS) in Spanish and English, translated it into four more languages, and optimized it for web-based presentation using the HealthTrackerTM platform. Of the total 19 questions developed for the STOP-SAS, four questions that assess low-level suicidality were identified as screening questions (three of them for use with children, and all four for use with adolescents, parents and clinicians). A total of 395 adolescents, 110 children, 637 parents and 716 clinicians completed the questionnaire using the HealthTrackerTM, allowing us to evaluate the internal consistency and convergent validity of the STOP-SAS with the clinician-rated Columbia Suicide Severity Rating Scale (C-SSRS). Validity was also assessed with the receiver operating characteristic (ROC) area of the STOP-SAS with the C-SSRS. RESULTS: The STOP-SAS comprises 19 items in its adolescent, parent, and clinician versions, and 14 items in its children's version. Good internal consistency was found for adolescents (Cronbach's alpha: 0.965), children (Cronbach's alpha: 0.922), parents (Cronbach's alpha: 0.951) and clinicians (Cronbach's alpha: 0.955) versions. A strong correlation was found between the STOP-SAS and the C-SSRS for adolescents (r:0.670), parents (r:0.548), clinicians (r:0.863) and children (r:0.654). The ROC area was good for clinicians' (0.917), adolescents' (0.834) and parents' (0.756) versions but only fair (0.683) for children's version. CONCLUSIONS: The STOP-SAS is a comprehensive, web-based PROM developed on the HealthTrackerTM platform, and co-designed for use by adolescents, children, parents and clinicians. It allows the evaluation of aspects of suicidality and shows good reliability and validity.

Grid patterns, spatial inter-scan variations and scanning reading repeatability in radiochromic film dosimetry.

PURPOSE: When comparing different scans of the same radiochromic film, several patterns can be observed. These patterns are caused by different sources of uncertainty, which affect the repeatability of the scanner. The purpose of this work was to study these uncertainties. METHODS: The variance of the scanner noise, as a function of the pixel position, was studied for different resolutions. The inter-scan variability of the scanner response was analyzed taking into account spatial discrepancies. Finally, the distance between the position of the same point in different scans was examined. RESULTS: The variance of noise follows periodical patterns in both axes, causing the grid patterns. These patterns were identified for resolutions of 50, 72 and 96dpi, but not for 150dpi. Specially recognizable is the sinusoidal shape with a period of 8.5mm that is produced with 72dpi. Inter-scan variations of the response caused systematic relative dose deviations larger than 1% in 5% of the red channel images, 9% of the green and 51% of the blue. No systematic deviation larger than 1% was found after applying response corrections. The initial positioning and the speed of the scanner lamp vary between scans. CONCLUSIONS: Three new sources of uncertainty, which influence radiochromic film dosimetry with flatbed scanners, have been identified and analyzed in this work: grid patterns, spatial inter-scan variations and scanning reading repeatability. A novel correction method is proposed, which mitigates spatial inter-scan variations caused by deviations in the autocalibration of the individual Charge Coupled Device detectors.

Frequency of virulence genes in mixed infections with Helicobacter pylori strains from a Mexican population.

BACKGROUND: Helicobacter pylori (H. pylori) is associated with gastroduodenal diseases. Virulence of clinical isolates is related to clinical outcome. Moreover, with microdiversity studies in clinical isolates from a single patient, but from a different origin (antrum or corpus), it is possible to demonstrate that there are simultaneous mixed infections. AIMS: To genotype H. pylori strains with multiplex PCR, according to their clinical virulence, and in this manner know the frequency of each genotype and relate it to clinical outcome in order to prevent the development of severe diseases. METHODS: A total of 210 patients with gastric alterations were studied. Virulence classification of H. pylori strains was carried out with multiplex PCR and 127 strains were identified as H. pylori by PCR (glmM and cagE). Genotype and clinical outcome were evaluated with the Fisher's exact test. In addition, RAPD-PCR was performed as a fingerprinting method to analyze mixed infections. RESULTS: The cagA, vacAs1, and vacAm1 genes were detected in all the clinical isolates. Strains were classified as: type i, 40.15% (51/127); type ii, 22.04% (28/127); and type iii, 28.4% (36/127), but two new different genotypes were also detected: (1) babA2+, cagA+, vacAs1+, 6.29% (8/127) and (2) babA2+, cagA-, vacAs2/m2+, 3.14% (4/127). The cagE gene was detected in type i strains. CONCLUSIONS: The Fisher's exact test did not support a significant association between clinical outcome and genotype. The main circulating genotypes in the Mexican population studied were: cagA+, vacAs1, and vacAm1. Multiplex PCR can be used as a screening test for H. pylori strains. Furthermore, the cagE gene is a good marker for identifying cag-PAI positive strains.

Model selection for radiochromic film dosimetry.

The purpose of this study was to find the most accurate model for radiochromic film dosimetry by comparing different channel independent perturbation models. A model selection approach based on (algorithmic) information theory was followed, and the results were validated using gamma-index analysis on a set of benchmark test cases. Several questions were addressed: (a) whether incorporating the information of the non-irradiated film, by scanning prior to irradiation, improves the results; (b) whether lateral corrections are necessary when using multichannel models; (c) whether multichannel dosimetry produces better results than single-channel dosimetry; (d) which multichannel perturbation model provides more accurate film doses. It was found that scanning prior to irradiation and applying lateral corrections improved the accuracy of the results. For some perturbation models, increasing the number of color channels did not result in more accurate film doses. Employing Truncated Normal perturbations was found to provide better results than using Micke-Mayer perturbation models. Among the models being compared, the triple-channel model with Truncated Normal perturbations, net optical density as the response and subject to the application of lateral corrections was found to be the most accurate model. The scope of this study was circumscribed by the limits under which the models were tested. In this study, the films were irradiated with megavoltage radiotherapy beams, with doses from about 20-600 cGy, entire (8 inch × 10 inch) films were scanned, the functional form of the sensitometric curves was a polynomial and the different lots were calibrated using the plane-based method.

Escherichia coli-induced temporal and differential secretion of heat-shock protein 70 and interleukin-1ß by human fetal membranes in a two-compartment culture system.

INTRODUCTION: Escherichia coli is recognized as an etiological bacteria associated with chorioamnionitis and the preterm premature rupture of fetal membranes. This pathological condition induces pro-inflammatory cytokines and degradative metalloproteinases, which are considered biological markers secreted in an acute stage of infection. Heat-shock proteins (HSPs) are an important component of the innate immunity response and are found in different pathological conditions. They have not been previously measured in human fetal membranes in response to infectious conditions. We hypothesized that the choriodecidual tissue and amniotic epithelium secreted temporal and differential Hsp-60, Hsp-70, and interleukin (IL)-1ß mediated by E. coli infection. METHODS: Fetal membranes were mounted in a two-compartment culture system and infected with two passes of live E. coli at different doses (10², 104, 105, and 106 colony-forming units (CFU)/mL) and intervals of incubation (3, 6, and 24 h). The culture medium was collected, and Hsp-60, Hsp-70, and IL-1ß were assessed using the enzyme-linked immunosorbent assay (ELISA) method. RESULTS: After 3 and 6 h of infection, E. coli induced an increase in Hsp-70 secretion in the choriodecidual tissue. However, after 24 h of incubation, Hsp-70 was downregulated and we observed an increase in IL-1ß secretion. By contrast, E. coli induced a lower Hsp-60 secretion in the amnion compared to Hsp-70. DISCUSSION: Human fetal membranes responded actively to E. coli infection, with an increase in Hsp-70 during the first hours of infection. After 24 h, there was an increase in the liberation of IL-1ß.

High frequency and founder effect of the CYP3A4*20 loss-of-function allele in the Spanish population classifies CYP3A4 as a polymorphic enzyme.

Cytochrome P450 3A4 (CYP3A4) is a key drug-metabolizing enzyme. Loss-of-function variants have been reported as rare events, and the first demonstration of a CYP3A4 protein lacking functional activity is caused by CYP3A4*20 allele. Here we characterized the world distribution and origin of CYP3A4*20 mutation. CYP3A4*20 was determined in more than 4000 individuals representing different populations, and haplotype analysis was performed using CYP3A polymorphisms and microsatellite markers. CYP3A4*20 allele was present in 1.2% of the Spanish population (up to 3.8% in specific regions), and all CYP3A4*20 carriers had a common haplotype. This is compatible with a Spanish founder effect and classifies CYP3A4 as a polymorphic enzyme. This constitutes the first description of a CYP3A4 loss-of-function variant with high frequency in a population. CYP3A4*20 results together with the key role of CYP3A4 in drug metabolism support screening for rare CYP3A4 functional alleles among subjects with adverse drug events in certain populations.

On multichannel film dosimetry with channel-independent perturbations.

PURPOSE: Different multichannel methods for film dosimetry have been proposed in the literature. Two of them are the weighted mean method and the method put forth by Micke et al. ["Multichannel film dosimetry with nonuniformity correction," Med. Phys. 38, 2523-2534 (2011)] and Mayer et al. ["Enhanced dosimetry procedures and assessment for EBT2 radiochromic film," Med. Phys. 39, 2147-2155 (2012)]. The purpose of this work was to compare their results and to develop a generalized channel-independent perturbations framework in which both methods enter as special cases. METHODS: Four models of channel-independent perturbations were compared: weighted mean, Micke-Mayer method, uniform distribution, and truncated normal distribution. A closed-form formula to calculate film doses and the associated type B uncertainty for all four models was deduced. To evaluate the models, film dose distributions were compared with planned and measured dose distributions. At the same time, several elements of the dosimetry process were compared: film type EBT2 versus EBT3, different waiting-time windows, reflection mode versus transmission mode scanning, and planned versus measured dose distribution for film calibration and for γ-index analysis. The methods and the models described in this study are publicly accessible through IRISEU. Alpha 1.1 (http://www.iriseu.com). IRISEU. is a cloud computing web application for calibration and dosimetry of radiochromic films. RESULTS: The truncated normal distribution model provided the best agreement between film and reference doses, both for calibration and γ-index verification, and proved itself superior to both the weighted mean model, which neglects correlations between the channels, and the Micke-Mayer model, whose accuracy depends on the properties of the sensitometric curves. With respect to the selection of dosimetry protocol, no significant differences were found between transmission and reflection mode scanning, between 75 ± 5 min and 20 ± 1 h waiting-time windows or between employing EBT2 or EBT3 films. Significantly better results were obtained when a measured dose distribution was used instead of a planned one as reference for the calibration, and when a planned dose distribution was used instead of a measured one as evaluation for the γ-analysis. CONCLUSIONS: The truncated normal distribution model of channel-independent perturbations was found superior to the other three models under comparison and the authors propose its use for multichannel dosimetry.

Effects of seed burial on germination, protein mobilisation and seedling survival in Dodonaea viscosa.

Ecological restoration of disturbed areas requires substantial knowledge of the germination of native plants and the creation of novel methods to increase seedling establishment in the field. We studied the effects of soil matrix priming on the germination of Dodonaea viscosa seeds, which exhibit physical dormancy. To this end, we buried both pre-scarified (in H2SO4, 3 min) and non-pre-scarified seeds in the Parque Ecológico de la Ciudad de México. After seeds were unearthed, they were post-scarified for 0, 2, 6 and 10 min and their germination percentages compared to the germination of a control batch of laboratory-stored seeds. For both control and unearthed seeds, the protein pattern was determined in the enriched storage protein fraction in SDS-PAGE gels stained with Coomassie blue. Percentage germination increased as the scarification time increased. Pre-scarification significantly increased percentage germination of post-scarified seeds in relation to the control and non-pre-scarified seeds. In seeds unearthed from the forest site, the buried pre-scarified seeds had relatively high percentage germination, even in the absence of post-scarification treatment. A 48-kDa protein was not found in unearthed, pre-scarified seeds nor in the control germinated seeds, indicating that mobilisation of this protein occurred during soil priming. Burying seeds for a short period, including the beginning of the rainy season, promoted natural priming, which increased protein mobilisation. Functionally, priming effects were reflected in high percentage seedling survival in both the shade house and the field. Seed burial also reduced the requirement for acidic post-scarification.

Algorithm for brain extraction on Magnetic Resonance Images T1 using Morphological 3D Transformations / Algoritmo para la extracción de imágenes de resonancia magnética T1 usando transformaciones morfológicas en 3D

In this paper a 3D morphological composition of transformations for brain extraction on brain Magnetic Resonance Images T1 (MRI T1) is presented. The proposal makes use of two morphological connected transformations, the lower leveling and a family of the viscous alternating sequential filters (VASFs). The properties of these operators -which consist in the control of the reconstruction process of a marker into the original image-, are exploited to segment the brain in 20 volumes of MRI T1. The segmented brains are compared with respect to: i) the segmentations obtained from BET which is popular among the scientific community for segmenting the brain; and ii) manual segmentations. The computed indices indicate that the proposed transformation produces good results during its performance. The consumed time for the algorithm during the execution is acceptable and it can be implemented in Matlab.

En este artículo se presenta una composición de transformaciones morfológicas para la extracción del cerebro en imágenes de resonancia magnética T1 (MRI T1) en 3D. La propuesta hace uso de dos transformaciones morfológicas conexas, la nivelación inferior y una familia de filtros viscosos alternados secuenciales (VASFs). Las propiedades de estos operadores- las cuales consisten en el control del proceso de reconstrucción de un marcador dentro de la imagen original-, se explotan para segmentar el cerebro de 20 volúmenes de MRI T1. Los cerebros segmentados se comparan respecto a: i) segmentaciones obtenidas a partir del algoritmo BET, el cual es popular en la comunidad científica para la segmentación del cerebro; y ii) segmentaciones manuales. Los índices calculados indican que la transformación propuesta produce buenos resultados en su desempeño. El tiempo empleado por el operador durante su ejecución es aceptable además de que la propuesta puede ser implementada en Matlab.

Assessment of in vitro removal of cholesterol oxidation products by Lactobacillus casei ATCC334.

Cholesterol oxidation products (COPs) are a group of compounds formed during processing and storage of foods from animal origin. After ingestion, COPs are absorbed in the intestine and can be distributed to serum and various tissues, potentially promoting a variety of toxic effects. Therefore, inhibition of their intestinal absorption may contribute to reduce the health risks associated with dietary intake of COPs. Some studies have shown that drugs and dietary compounds may inhibit the intestinal absorption of dietary COPs. However, proven cholesterol- and/or food toxins-binding lactic acid bacteria have not been previously evaluated as potential COPs removal agents. The aim of this study was to assess the ability of Lactobacillus casei ATCC334 to remove COPs in aqueous solution. Results showed the ability of both growing and resting cells to remove COPs (ca. 30-60%). All COPs-bacterium interactions were specific and partly reversible, being resting cells the most efficient for COPs removal in a ranking order of 7-KC > 7α-OH/7ß-OH > triol > 5,6ß-EP > 5,6α-EP > 25-OH. Binding to the cell wall and/or cell membrane incorporation appears to be the most likely mechanisms involved on COPs removal by L. casei ATCC 334.

Gafchromic EBT2 film dosimetry in reflection mode with a novel plan-based calibration method.

PURPOSE: A dosimetric system formed by Gafchromic EBT2 radiochromic film and Epson Expression 10000XL flatbed scanner was commissioned for dosimetry. In this paper, several open questions concerning the commissioning of radiochromic films for dosimetry were addressed: (a) is it possible to employ this dosimetric system in reflection mode; (b) if so, can the methods used in transmission mode also be used in reflection mode; (c) is it possible to obtain accurate absolute dose measurements with Gafchromic EBT2 films; (d) which calibration method should be followed; (e) which calibration models should be used; and (f) does three-color channel dosimetry offer a significant improvement over single channel dosimetry. The purpose of this paper is to help clarify these questions. METHODS: In this study, films were scanned in reflection mode, the effect of surrounding film was evaluated and the feasibility of EBT2 film dosimetry in reflection mode was studied. EBT2's response homogeneity has been reported to lead to excessive dose uncertainties. To overcome this problem, a new plan-based calibration method was implemented. Plan-based calibration can use every pixel and each of the three color channels of the scanned film to obtain the parameters of the calibration model. A model selection analysis was conducted to select lateral correction and sensitometric curve models. The commonly used calibration with fragments was compared with red-channel plan-based calibration and with three-channel plan-based calibration. RESULTS: No effect of surrounding film was found in this study. The film response inhomogeneity in EBT2 films was found to be important not only due to differences in the fog but also due to differences in sensitivity. The best results for lateral corrections were obtained using absolute corrections independent of the dose. With respect to the sensitometric curves, an empirical polynomial fit of order 4 was found to obtain results equivalent to a gamma-distributed single hit model based on physical assumptions. Three-channel dosimetry was found to be substantially superior to red-channel dosimetry. CONCLUSIONS: Reflection mode with Gafchromic EBT2 radiochromic film was found to be a viable alternative to transmission mode. The same methods that are used in transmission mode can be followed in reflection mode. A novel plan-based method was developed for calibration and multichannel dosimetry. This novel method offers increased robustness against film response inhomogeneities and reduces considerably the time required for calibration.