Hosing of a Long Relativistic Particle Bunch in Plasma.

Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven by a short, misaligned preceding bunch. Hosing develops in the plane of misalignment, self-modulation in the perpendicular plane, at frequencies close to the plasma electron frequency, and are reproducible. Development of hosing depends on misalignment direction, its growth on misalignment extent and on proton bunch charge. Results have the main characteristics of a theoretical model, are relevant to other plasma-based accelerators and represent the first characterization of hosing.

Heavy quasiparticles and cascades without symmetry breaking in twisted bilayer graphene.

Among the variety of correlated states exhibited by twisted bilayer graphene, cascades in the spectroscopic properties and in the electronic compressibility occur over larger ranges of energy, twist angle and temperature compared to other effects. This suggests a hierarchy of phenomena. Using a combined dynamical mean-field theory and Hartree calculation, we show that the spectral weight reorganisation associated with the formation of local moments and heavy quasiparticles can explain the cascade of electronic resets without invoking symmetry breaking orders. The phenomena reproduced here include the cascade flow of spectral weight, the oscillations of remote band energies, and the asymmetric jumps of the inverse compressibility. We also predict a strong momentum differentiation in the incoherent spectral weight associated with the fragile topology of twisted bilayer graphene.

Water in the terrestrial planet-forming zone of the PDS 70 disk.

Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 AU) regions of protoplanetary disks1. Water plays a key role in their formation2-4, although it is yet unclear whether water molecules are formed in situ or transported from the outer disk5,6. So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks7, similar to PDS 70, the first system with direct confirmation of protoplanet presence8,9. Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 AU) planet-carved gap separating an inner and outer disk10,11. Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H2 and/or OH, and survival through water self-shielding5. This is also supported by the presence of CO2 emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir12. Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.

Modification of physico-chemical surface properties and growth of Staphylococcus aureus under hyperglycemia and ketoacidosis conditions.

Diabetes is a widely spread disease affecting the quality of life of millions of people around the world and is associated to a higher risk of developing infections in different parts of the body. The reasons why diabetes enhances infection episodes are not entirely clear; in this study our aim was to explore the changes that one of the most frequently pathogenic bacteria undergoes when exposed to hyperglycemia and ketoacidosis conditions. Physical surface properties such as hydrophobicity and surface electrical charge are related to bacterial growth behavior and the ability of Staphylococcus aureus to form biofilms. The addition of glucose made bacteria more negatively charged and with moderate-intermediate hydrophobicity. Ketone bodies increased hydrophobicity to approximately 75% and pathological concentrations hindered some of the bacterial surface charge by decreasing the negative zeta potential of cells. When both components were present, the bacterial physical surface changes were more similar to those observed in ketone bodies, suggesting a preferential adsorption of ketone bodies over glucose because of the more favorable solubility of glucose in water. Glucose diabetic concentrations gave the highest number of bacteria in the stationary phase of growth and provoked an increase in the biofilm slime index of around 400% in relation to the control state. Also, this situation is related with an increase of bacterial coverage. The combination of a high concentration of glucose and ketone bodies, which corresponds to a poorly controlled diabetic situation, appears associated with an early infection phase; increased hydrophobic attractive force and reduced electrostatic repulsion between cells results in better packing of cells within the biofilm and more efficient retention to the host surface. Knowledge of bacterial response in high amount of glucose and ketoacidosis environments can serve as a basis for designing strategies to prevent bacterial adhesion, biofilm formation and, consequently, the development of infections.

Decomposition of Growth Curves into Growth Rate and Acceleration: a Novel Procedure To Monitor Bacterial Growth and the Time-Dependent Effect of Antimicrobials.

In this paper, a simple numerical procedure is presented to monitor the growth of Streptococcus sanguinis over time in the absence and presence of propolis, a natural antimicrobial. In particular, it is shown that the real-time decomposition of growth curves obtained through optical density measurements into growth rate and acceleration can be a powerful tool to precisely assess a large range of key parameters (i.e., lag time [t0], starting growth rate [γ0], initial acceleration of the growth [a0], maximum growth rate [γmax], maximum acceleration [amax], and deceleration [amin] of the growth and the total number of cells at the beginning of the saturation phase [Ns]) that can be readily used to fully describe growth over time. Consequently, the procedure presented provides precise data of the time course of the different growth phases and features, which is expected to be relevant, for instance, to thoroughly evaluate the effect of new antimicrobial agents. It further provides insight into predictive microbiology, likely having important implications for assumptions adopted in mathematical models to predict the progress of bacterial growth. IMPORTANCE The new and simple numerical procedure presented in this paper to analyze bacterial growth will possibly allow the identification of true differences in efficacy among antimicrobial drugs for their applications in human health, food security, and the environment, among others. It further provides insight into predictive microbiology, likely helping in the development of proper mathematical models to predict the course of bacterial growth under diverse circumstances.

Antimicrobial activity of a novel Spanish propolis against planktonic and sessile oral Streptococcus spp.

Increased bacterial resistance to traditional antimicrobial agents has prompted the use of natural products with antimicrobial properties such as propolis, extensively employed since ancient times. However, the chemical composition of propolis extracts is extremely complex and has been shown to vary depending on the region and season of collection, due to variations in the flora from which the pharmacological substances are obtained, being therefore essential for their antimicrobial activity to be checked before use. For this purpose, we evaluate the in vitro antimicrobial and anti-biofilm activity of a new and promising Spanish ethanolic extract of propolis (SEEP) on Streptococcus mutans and Streptococcus sanguinis, responsible, as dominant 'pioneer' species, for dental plaque. Results reveal that S. sanguinis is more sensitive to SEEP, slowing and retarding its growth considerably with lower concentrations than those needed to produce the same effect in S. mutans. SEEP presents concentration- and time-dependent killing activity and, furthermore, some of the subinhibitory concentrations employed increased biofilm formation even when bacterial growth decreased. Mono and dual-species biofilms were also inhibited by SEEP. Findings obtained clearly show the relevance of using biofilm and subinhibitory concentration models to determine optimal treatment concentrations.

Bronchobiliary fistula: a clinical and surgical challenge. Presentation of a pediatric case. / Fístula biliobronquial, un desafio clínico-quirúrgico. Presentación de un caso pediátrico.

INTRODUCTION: Congenital bronchobiliary fistula is an extremely rare malformation with high morbidity and mortality rates. Up to 2016, 36 cases had been reported worldwide. CLINICAL CASE: 11-year-old male patient with history of chronic lung disease and respiratory insufficiency, bile ptyalism and 66-80% arterial saturation, jaundice, asymmetric thorax, finger clubbing, and disseminated crackling rales. He was diagnosed through fibrobronchoscopy and CT-scan. After fistula closure and right pneumonectomy, recurrence occurred due to bile duct hypoplasia as evidenced by endoscopic retrograde cholangiopancreatography. Left lateral hepatic segmentectomy and fistula closure from the abdomen were carried out. Bronchopleural fistula persisted following intensive nutritional and antibiotic treatment. It was surgically closed using a bovine pericardial patch. Six months later, the patient had no symptoms. DISCUSSION: Given how extremely rare this malformation is, cross-disciplinary treatment and a high grade of suspicion are needed. The presence of bile duct hypoplasia is to be considered, since it requires a thoracoabdominal approach.

INTRODUCCION: La fístula biliobronquial congénita es una muy rara malformación con alta morbimortalidad. Hasta 2016 se habían reportado 36 casos en el mundo. CASO CLINICO: Paciente masculino de 11 años de edad, antecedentes de neumopatía crónica más insuficiencia respiratoria, bilioptisis, saturación arterial entre 66-80%, ictericia, tórax asimétrico, dedos hipocráticos, estertores crepitantes diseminados. Diagnóstico positivo por fibrobroncoscopia y tomografia axial computarizada. Tras cierre de fístula y neumonectomía derecha, se produjo recidiva por hipoplasia de la vía biliar comprobada con colangiopancreatografía retrógrada endoscópica. Se realizó segmentectomía hepática lateral izquierda y cierre de fístula desde el abdomen. Mantuvo fístula broncopleural persistente, luego de tratamiento nutricional y antibiótico intensivo, se cerró quirúrgicamente con parche de pericardio bovino. Asintomático tras 6 meses. COMENTARIOS: La muy baja frecuencia de esta malformación obliga a un alto índice de sospecha y un tratamiento multidisciplinario. Es importante considerar la presencia de hipoplasia de la vía biliar pues obliga a un abordaje toracoabdominal.

Fístula biliobronquial, un desafio clínico-quirúrgico. Presentación de un caso pediátrico / Bronchobiliary fistula: a clinical and surgical challenge. Presentation of a pediatric case

Introducción: La fístula biliobronquial congénita es una muy raramalformación con alta morbimortalidad. Hasta 2016 se habían reportado36 casos en el mundo. Caso clínico: Paciente masculino de 11 años de edad, antecedentesde neumopatía crónica más insuficiencia respiratoria, bilioptisis, saturación arterial entre 66-80%, ictericia, tórax asimétrico, dedos hipocráticos, estertores crepitantes diseminados. Diagnóstico positivo por fibrobroncoscopia y tomografia axial computarizada. Tras cierre de fístulay neumonectomía derecha, se produjo recidiva por hipoplasia de la víabiliar comprobada con colangiopancreatografía retrógrada endoscópica.Se realizó segmentectomía hepática lateral izquierda y cierre de fístuladesde el abdomen. Mantuvo fístula broncopleural persistente, luego detratamiento nutricional y antibiótico intensivo, se cerró quirúrgicamentecon parche de pericardio bovino. Asintomático tras 6 meses. Comentarios: La muy baja frecuencia de esta malformación obligaa un alto índice de sospecha y un tratamiento multidisciplinario. Esimportante considerar la presencia de hipoplasia de la vía biliar puesobliga a un abordaje toracoabdominal.(AU)

Introduction: Congenital bronchobiliary fistula is an extremely raremalformation with high morbidity and mortality rates. Up to 2016, 36cases had been reported worldwide. Clinical case: 11-year-old male patient with history of chronic lungdisease and respiratory insufficiency, bile ptyalism and 66-80% arterialsaturation, jaundice, asymmetric thorax, finger clubbing, and dissem-inated crackling rales. He was diagnosed through fibrobronchoscopyand CT-scan. After fistula closure and right pneumonectomy, recurrenceoccurred due to bile duct hypoplasia as evidenced by endoscopic retro-grade cholangiopancreatography. Left lateral hepatic segmentectomy and fistula closure from the abdomen were carried out. Bronchopleuralfistula persisted following intensive nutritional and antibiotic treatment. It was surgically closed using a bovine pericardial patch. Six monthslater, the patient had no symptoms. Discussion: Given how extremely rare this malformation is,cross-disciplinary treatment and a high grade of suspicion are needed.The presence of bile duct hypoplasia is to be considered, since it requiresa thoracoabdominal approach.(AU)

Tratamiento quirúrgico de la gangrena de Fournier / Surgical management of Fournier's gangrene

Resumen Objetivo: Describir el manejo quirúrgico realizado para la reconstrucción genitoperineal (RGP) en pacientes con secuelas de Gangrena de Fournier (GF). Materiales y Método: Corresponde a una serie de casos retrospectiva de pacientes con secuelas de GF a los que se les realizó RGP entre los años 2011 y 2019. Se realizó un análisis descriptivo con las variables de técnica quirúrgica, edad, sexo, comorbilidades, subunidades anatómicas afectadas, origen anatómico de la gangrena de Fournier, número de procedimientos quirúrgicos, procedimiento de colostomía, terapia de presión negativa, Flexi-Seal®, bacterias aisladas, duración de estancia hospitalaria, tipo de procedimientos reconstructivos y complicaciones. Resultados: Se realizó RGP a 43 pacientes (81,1% hombres), con un promedio de edad de 59,1 (17-86 años), 72,7% eran diabéticos. El número de subunidades involucradas se asocia directamente y significativamente en relación al número de intervenciones quirúrgicas. Las técnicas utilizadas para la reconstrucción en orden de frecuencia fueron: colgajos (23%), cierre parcial más injerto dermoepidérmico de grosor parcial (IPP) (20%), cierre parcial (16%) e IPP (16%), cierre por segunda intención (10%), colgajo más IPP (7%) y cierre parcial para cierre por segunda intención de zona restante (5%). Discusión: La elección de reconstrucción se basa en las características del defecto, es decir, el tamaño, la ubicación y profundidad, así como la disponibilidad de tejido local. De preferencia optar por cierres primarios sin tensión, seguido de colgajos y de IPP. Conclusión: La RGP es un desafío para el cirujano plástico. Las técnicas descritas han demostrado ser seguras y reproducibles para el tratamiento quirúrgico de la gangrena de Fournier.

Aim: To describe the surgical management performed for genital-perineal reconstruction (GPR) in patients with sequelae of Fournier gangrene (FG). Materials and Method: It is based on a retroactive series of cases of patients with effects of FG who were given GPR between 2011 and 2019. We performed a descriptive analysis using the variables surgical technique, age, sex, comorbidities, anatomical subunits affected, anatomic origin of the Fournier's gangrene, number of surgical procedures, colostomy procedure, negative pressure therapy, Flexi-Seal®, bacteria isolated, hospital stay, type of reconstructive procedures and complications. We performed GPR on 43 patients (81.1% male), with a mean age of 59.1 (17-86 years); 72% were diabetic. The number of subunits involved was directly and significantly associated with the number of surgical interventions. Results: The reconstruction techniques most used were, in descending order: flaps (23.2%), wound closure and split-thickness skin graft (STSG) (23.2%), primary closure (16.2%), STSG (16.2%), secondary closure (9.3%), flap and STSG (6.9%) and partial wound closure for healing of the remaining area for a second intention (4.6%). Discussion: The reconstruction choice is based on the characteristics of the defect, that is, the size, location and depth, as well as the availability of local tissue. Preferably opt for primary closures without tension, followed by flaps and IPP. Conclusion: The RGP is a challenge for the plastic surgeon. The techniques described have proven safe and reproducible for the surgical treatment of Fournier Gangrene.

MgO surface lattice phonons observation during interstellar ice transition.

Relevant information on the origins of the solar system and the early evolution of life itself can be derive from systematic and controlled exploration of water ice here on Earth. Therefore, over the last decades, a huge effort on experimental methodologies has been made to study the multiple crystal ice phases, which are observed outside our home-gravitational-potential. By employing (100)-oriented MgO lattice surface as a microcantilever sensor, we conducted the first ever study on the dynamics of the Structural Phase Transition at 185 K in water ice by means of coherent elastic scattering of electron diffraction. We estimate the amount of phonons caused by this transition applying precise quantum computing key tools, and resulting in a maximum value of 1.23 ± 0.02. Further applications of our microcantilever sensor were assessed using unambiguous mapping of the surface stress induced by the c([Formula: see text]) → p([Formula: see text]) Structural Phase Transition of the interstellar ice formulated on the Williamsom-Hall model. This development paves the way and thus establishes an efficient characterization tool of the surface mechanical strains of materials with potential applications arising from interstellar ice inclusive glaciers to the wide spectrum of solid-state physics.

Bloqueo del plano del erector espinal bilateral para cirugía de pectus excavatum en paciente pediátrico / Bilateral spinal erector plane block for pectus excavatum surgery in pediatric patient

El bloqueo del plano del erector espinal es una técnica de anestesia regional con resultados favorables en el manejo del dolor postoperatorio en pacientes pediátricos. Los reportes son escasos en Latinoamérica. Presentamos el caso de un paciente de 5 años con diagnóstico de pectus excavatum sometido a técnica quirúrgica convencional (técnica de Ravitch). Se realiza el bloqueo del plano del erector espinal bilateral con guía ecográfica a nivel de la apófisis transversa de T5 obteniéndose una adecuada estabilidad hemodinámica intraoperatoria y analgesia postoperatoria.(AU)

The spinal erector plane block is a regional anesthesia technique with favorable results in the management of postoperative pain in pediatric patients. Reports are few in Latin America. We present the case of a 5-year-old patient with a diagnosis of Pectus Excavatum undergoing a conventional surgical technique (Ravitch technique). Bilateral erector spinae plane block is performed with ultrasound guidance at the level of the transverse process of T5, obtaining adequate intraoperative hemodynamic stability and postoperative analgesia.(AU)

Double crush syndrome: Epidemiology, diagnosis, and treatment results.

BACKGROUND: Double Crush Syndrome (DCS) is a clinical condition that involves multiple compression sites along a single peripheral nerve. The present study aims to describe the epidemiology of DCS and surgical results. METHODS: A retrospective observational analytic study included patients with clinical diagnosis of cervical radiculopathy and carpal tunnel syndrome who underwent surgery between January 2009 and January 2019. General demographic characteristics were noted, and 3 groups were distinguished: spinal surgery, carpal tunnel release, and bimodal decompression (BD); statistical differences were analyzed between them. RESULTS: The sample comprised 32 patients. DCS prevalence was 10.29%. Mean age at presentation was 59.25±10.98 years. There was female predominance (75%). Paresthesia was the main symptom (65.6%). Post-surgical results of BD showed significant improvement in sensory nerve conduction velocity, motor nerve conduction velocity (both P=0.008), and disability on Douleur Neuropathique 4 questions, Neck Disability Index, and Boston Carpal Tunnel Questionnaire (P=0.001, 0.004, 0.008, respectively). CONCLUSIONS: Diagnosis and management of DCS are a challenge. It is necessary to determine the site with maximal compression and risk of complications to decide on treatment. If first-line surgery is adequate, proximal and distal symptomatology can be improved. To maximize success, we recommend BD, according to the present results.

Construcción y validación de la escala de predicción y valoración del riesgo de violencia (EPERV-55) en trastorno mental grave / Construction and validation of the violence risk prediction and assessment scale (EPERV-55) in severe mental disorder

OBJETIVO: diseñar y validar la Escala de Predicción y Evaluación de Riesgo de Violencia (EPERV-55) en personas con trastorno mental grave (TMG) hospitalizadas en unidades de media y larga estancia. MÉTODO: se elaboró un cuestionario EPERV-55, con 55 ítems, en función de la literatura revisada y del conocimiento del equipo investigador sobre diferentes herramientas de predicción y evaluación de violencia en TMG. Se integraron datos clínicos de predicción y de gestión del riesgo, incluyendo la taxonomía NANDA/NOC. Para la validez de constructo se obtuvieron datos de pacientes ingresados en Unidades de Salud Mental del Hospital Parc Sanitari Sant Joan de Déu (Barcelona). Se valoró la consistencia interna de la escala con el coeficiente alfa de Cronbach. La validez convergente se evaluó mediante el coeficiente de correlación de Rho de Spearman comparando la EPERV-55 con la Escala de Riesgo de Violencia de Plutchik. Para medir la sensibilidad y especificidad se utilizó el test U de Mann-Whitney. Los análisis se realizaron con los programas estadísticos R 2.13 y SPSS 19. RESULTADOS: participaron 177 sujetos. A escala presentó un alpha de Cronbach de 0,92. La fiabilidad test-retest fue buena en 23 ítems de la escala y moderado en 32 ítems. La validez convergente fue significativa con las escalas EPERV-55-RV (correl. Spearman: -0,348 y -0,458 respectivamente; p < 0,001). En la sensibilidad y especificidad se objetivaron diferencias significativas en violencia general (p < 0,004) y violencia heteroagresiva (p < 0,005). El índice de la curva de Roc fue significativa en violencia heteroagresiva, hacia objetos y general. CONCLUSIONES: la escala EPERV-55 es un instrumento válido para evaluar y predecir el riesgo de violencia en personas con TMG hospitalizadas en unidades de media y larga estancia

OBJECTIVE: to design and validate the Violence Risk Prediction and Assessment Scale (EPERV-55) in persons with severe mental disorder (SMD) hospitalized in medium and long-stay units. METHOD: an EPERV-55 questionnaire was prepared, including 55 items, based on the literature reviewed and the knowledge by the research team about different tools for violence prediction and evaluation in SMD. Clinical data on risk prediction and management were incorporated, including the NANDA/NOC taxonomy. For construction validity, data were collected from patients hospitalized in Mental Health Units of the Hospital Parc Sanitari Sant Joan de Déu (Barcelona). The internal consistency of the scale was assessed with Cronbach's Alpha Coefficient. Convergent validity was evaluated through Spearman's Rho Correlation Coefficient, comparing EPERV-55 vs. the Violence Risk Scale by Plutchik. Mann-Whitney's U Test was used in order to measure sensitivity and specificity; analyses were conducted with the R 2.13 and SPSS 19 statistic programs. RESULTS: the study included 177 subjects. The model presented 0.92 in Cronbach's alpha. Test-retest accuracy was good in 23 items of the scale, and moderate in 32 items. Convergent validity was significant with the EPERV-55-RV scales (Spearman's Correlation: -0.348 and -0.458 respectively; p < 0.001). Regarding sensitivity and specificity, significant differences were observed in Overall Violence (p < 0.004) and Hetero-aggressive Violence (p < 0.005). The Roc Curve index was significant in Hetero-aggressive Violence, against objects, and general. CONCLUSIONS: the EPERV-55 scale is a valid tool to evaluate and predict the risk of violence in persons with SMD hospitalized in medium and long-stay units

Meta-análisis para evaluar eficiencia de selección genómica en cereales: Meta-analysis for evaluating the efficiency of genomic selection in cereals

La selección genómica (SG) es usada para predecir el mérito de un genotipo respecto a un carácter cuantitativo a partir de datos moleculares o genómicos. Estadísticamente, la SG requiere ajustar un modelo de regresión con múltiples variables predictoras asociadas a los estados de los marcadores moleculares (MM). El modelo se calibra en una población en la que hay datos fenotípicos y genómicos. La abundancia y la correlación de la información de los MM dificultan la estimación, y por ello existen distintas estrategias para el ajuste del modelo basadas en: mejor predictor lineal insesgado (BLUP), regresiones Bayesianas y aprendizaje automático. La correlación entre el fenotipo observado y el mérito genético predicho por el modelo ajustado, provee una medida de eficiencia (capacidad predictiva) de la SG. El objetivo de este trabajo fue realizar un meta-análisis de la eficiencia de la SG en cereales. Se realizó una revisión sistemática de estudios relacionados a SG y se llevó a cabo un meta-análisis, para obtener una medida global de la eficiencia de la SG en trigo y maíz, bajo diferentes escenarios (cantidad de MM y método estadístico usado para la SG). El metaanálisis indicó un coeficiente de correlación promedio de 0,61 entre los méritos genéticos predichos y los fenotipos observados. No se observaron diferencias significativas en la eficiencia de la SG realizada con modelos basados en BLUP (RR-BLUP y GBLUP), enfoque estadístico más comúnmente usado. El incremento de MM no cambia significativamente la eficiencia de la SG.

Genomic selection (GS) is used to predict the merit of a genotype with respect to a quantitative trait from molecular or genomic data. Statistically, GS requires fitting a regression model with multiple predictors associated with the molecular markers (MM) states. The model is calibrated in a population with phenotypic and genomic data. The abundance and correlation of MM information make model estimation challenging. For that reason there are diverse strategies to adjust the model: based on best linear unbiased predictors (BLUP), Bayesian regressions and machine learning methods. The correlation between the observed phenotype and the predicted genetic merit by the fitted model provides a measure of the efficiency (predictive ability) of the GS. The objective of this work was to perform a metaanalysis on the efficiency of GS in cereals. A systematic review of related GS studies and a meta-analysis, in wheat and maize, was carried out to obtain a global measure of GS efficiency under different scenarios (MM quantity and statistical models used in GS). The meta-analysis indicated an average correlation coefficient of 0.61 between observed and predicted genetic merits. There were no significant differences in the efficiency of the GS based on BLUP (RR-BLUP and GBLUP), the most common statistical approach. The increase of MM data, make GS efficiency do not vary widely.

The role of magnesium in biomaterials related infections.

Magnesium is currently increasing interest in the field of biomaterials. An extensive bibliography on this material in the last two decades arises from its potential for the development of biodegradable implants. In addition, many researches, motivated by this progress, have analyzed the performance of magnesium in both in vitro and in vivo assays with gram-positive and gram-negative bacteria in a very broad range of conditions. This review explores the extensive literature in recent years on magnesium in biomaterials-related infections, and discusses the mechanisms of the Mg action on bacteria, as well as the competition of Mg2+ and/or synergy with other divalent cations in this subject.

Age-related changes in the articular cartilage of the mandible of rats.

This study investigated the effects of aging on the articular cartilage of the mandible. Wistar rats were divided in two groups (n = 10/per group): 3-months-old group (young group); and 13-months-old group (aged group). After euthanasia, the head of the mandible was collected and stained with hematoxylin and eosin (HE) to evaluate the thickness of the articular layer and cartilage. Sections stained with Picrosirius red and Safranin O were used to evaluate the collagen and proteoglycans deposition, respectively. First, aging has decreased the articular layer thickness. Second, the results suggest a decrease of chondrocytes followed by an increase of the matrix to maintain the mandible homeostasis. Finally, both collagen and proteoglycans increased with aging. Aging displayed important effects to the mandible of aged rats.