Oral pathology and oral medicine in Latin American countries: current stage.

BACKGROUND: Oral Pathology (OP) and Oral Medicine (OM) are specialties in dentistry whose main objective is the diagnosis and treatment of oral and maxillofacial diseases, and aspects related to the academic training of professionals and fields of practice are distinct and heterogeneous around the world. This study aimed to evaluate professional training and areas of activity in OP and OM in Latin American countries. MATERIAL AND METHODS: A questionnaire was sent to 11 countries, with a professional in each country responsible for answering it. The questionnaire had 21 questions related to the process of professional training, areas of practice, the existence of scientific events in each country, and also collected demographic and population information. RESULTS: OP and OM are practiced in all the countries studied, but the specialty is not recognized in all of them. Brazil was the first to recognize both as a specialty. Postgraduate programs designed to train specialists are available in various countries. Two countries offer residency programs, 6 countries provide specialization courses, 6 offer master's programs, and 3 have doctoral programs. Brazil boasts the highest number of undergraduate courses (n=412), while Uruguay has the lowest (n=2). Professional societies representing the specialty exist in ten countries. Brazil has the highest number of OP and OM specialists (n=422 and 1,072), while Paraguay has the smallest number (n=1 and 3). CONCLUSIONS: Although both specialties are widely practiced around the globe, professional training, the number of dentists trained and the fields of professional practice are very different between the countries studied.

Madrid-2019 force field: An extension to divalent cations Sr2+ and Ba2.

In this work, we present a parameterization of Sr2+ and Ba2+ cations, which expands the alkali earth set of cations of the Madrid-2019 force field. We have tested the model against the experimental densities of eight different salts, namely, SrCl2, SrBr2, SrI2, Sr(NO3)2, BaCl2, BaBr2, BaI2, and Ba(NO3)2. The force field is able to reproduce the experimental densities of all these salts up to their solubility limit. Furthermore, we have computed the viscosities for two selected salts, finding that the experimental values are overestimated, but the predictions are still reasonable. Finally, the structural properties for all the salts have been calculated with this model and align remarkably well with experimental observations.

Growth rate of CO2 and CH4 hydrates by means of molecular dynamics simulations.

CO2 and CH4 hydrates are of great importance both from an energetic and from an environmental point of view. It is therefore highly relevant to quantify and understand the rate with which they grow. We use molecular dynamics simulations to shed light on the growth rate of these hydrates. We put the solid hydrate phase in contact with a guest aqueous solution in equilibrium with the pure guest phase and study the growth of both hydrates at 400 bars with temperature. We compare our results with previous calculations of the ice growth rate. We find a growth rate maximum as a function of the supercooling in all cases. The incorporation of guest molecules into the solid structure strongly decelerates hydrate growth. Consistently, ice grows faster than either hydrate and the CO2 hydrate grows faster than the CH4 one because of the higher solubility of CO2. We also quantify the molecular motion required to build the solids under study and find that the distance traveled by liquid molecules exceeds by orders of magnitude that advanced by any solid. Less molecular motion is needed in order for ice to grow as compared to the hydrates. Moreover, when temperature increases, more motion is needed for solid growth. Finally, we find a good agreement between our growth rate calculations and experiments of hydrate growth along the guest-solution interface. However, more work is needed to reconcile experiments of hydrate growth toward the solution among each other and with simulations.

Minimum in the pressure dependence of the interfacial free energy between ice Ih and water.

Despite the importance of ice nucleation, this process has been barely explored at negative pressures. Here, we study homogeneous ice nucleation in stretched water by means of molecular dynamics seeding simulations using the TIP4P/Ice model. We observe that the critical nucleus size, interfacial free energy, free energy barrier, and nucleation rate barely change between isobars from -2600 to 500 bars when they are represented as a function of supercooling. This allows us to identify universal empirical expressions for homogeneous ice nucleation in the pressure range from -2600 to 500 bars. We show that this universal behavior arises from the pressure dependence of the interfacial free energy, which we compute by means of the mold integration technique, finding a shallow minimum around -2000 bars. Likewise, we show that the change in the interfacial free energy with pressure is proportional to the excess entropy and the slope of the melting line, exhibiting in the latter a reentrant behavior also at the same negative pressure. Finally, we estimate the excess internal energy and the excess entropy of the ice Ih-water interface.

Homogeneous nucleation rate of methane hydrate formation under experimental conditions from seeding simulations.

In this work, we shall estimate via computer simulations the homogeneous nucleation rate for the methane hydrate at 400 bars for a supercooling of about 35 K. The TIP4P/ICE model and a Lennard-Jones center were used for water and methane, respectively. To estimate the nucleation rate, the seeding technique was employed. Clusters of the methane hydrate of different sizes were inserted into the aqueous phase of a two-phase gas-liquid equilibrium system at 260 K and 400 bars. Using these systems, we determined the size at which the cluster of the hydrate is critical (i.e., it has 50% probability of either growing or melting). Since nucleation rates estimated from the seeding technique are sensitive to the choice of the order parameter used to determine the size of the cluster of the solid, we considered several possibilities. We performed brute force simulations of an aqueous solution of methane in water in which the concentration of methane was several times higher than the equilibrium concentration (i.e., the solution was supersaturated). From brute force runs, we infer the value of the nucleation rate for this system rigorously. Subsequently, seeding runs were carried out for this system, and it was found that only two of the considered order parameters were able to reproduce the value of the nucleation rate obtained from brute force simulations. By using these two order parameters, we estimated the nucleation rate under experimental conditions (400 bars and 260 K) to be of the order of log10 (J/(m3 s)) = -7(5).

Scaled charges for ions: An improvement but not the final word for modeling electrolytes in water.

In this work, we discuss the use of scaled charges when developing force fields for NaCl in water. We shall develop force fields for Na+ and Cl- using the following values for the scaled charge (in electron units): ±0.75, ±0.80, ±0.85, and ±0.92 along with the TIP4P/2005 model of water (for which previous force fields were proposed for q = ±0.85 and q = ±1). The properties considered in this work are densities, structural properties, transport properties, surface tension, freezing point depression, and maximum in density. All the developed models were able to describe quite well the experimental values of the densities. Structural properties were well described by models with charges equal to or larger than ±0.85, surface tension by the charge ±0.92, maximum in density by the charge ±0.85, and transport properties by the charge ±0.75. The use of a scaled charge of ±0.75 is able to reproduce with high accuracy the viscosities and diffusion coefficients of NaCl solutions for the first time. We have also considered the case of KCl in water, and the results obtained were fully consistent with those of NaCl. There is no value of the scaled charge able to reproduce all the properties considered in this work. Although certainly scaled charges are not the final word in the development of force fields for electrolytes in water, its use may have some practical advantages. Certain values of the scaled charge could be the best option when the interest is to describe certain experimental properties.

Melting points of water models: Current situation.

By using the direct coexistence method, we have calculated the melting points of ice Ih at normal pressure for three recently proposed water models, namely, TIP3P-FB, TIP4P-FB, and TIP4P-D. We obtained Tm = 216 K for TIP3P-FB, Tm = 242 K for TIP4P-FB, and Tm = 247 K for TIP4P-D. We revisited the melting point of TIP4P/2005 and TIP5P obtaining Tm = 250 and 274 K, respectively. We summarize the current situation of the melting point of ice Ih for a number of water models and conclude that no model is yet able to simultaneously reproduce the melting temperature of ice Ih and the temperature of the maximum in density at room pressure. This probably points toward our both still incomplete knowledge of the potential energy surface of water and the necessity of incorporating nuclear quantum effects to describe both properties simultaneously.

Counting on U training to enhance trusting relationships and mental health literacy among business advisors: protocol for a randomised controlled trial.

BACKGROUND: Financial distress is thought to be a key reason why small-medium enterprise (SME) owners experience higher levels of mental health conditions compared with the broader population. Business advisors who form trusting, high-quality relationships with their SME clients, are therefore well placed to: (1) help prevent/reduce key sources of financial distress, (2) better understand the business and personal needs of their clients and, (3) recognise the signs and symptoms of mental health conditions and encourage help-seeking where appropriate. The aim of this study is to compare the effectiveness of relationship building training (RBT) combined with mental health first aid (MHFA) training for business advisors with MHFA alone, on the financial and mental health of their SME-owner clients. METHODS: This is a single blind, two-arm randomised controlled trial. Participants will be business advisors who provide information, guidance and/or assistance to SME owner clients and are in contact with them at least 3 times a year. The business advisors will invite their SME-owner clients to complete 3 online surveys at baseline, 6- and 12-months. Business advisors will be randomised to one of two conditions, using a 1:1 allocation ratio: (1) MHFA with RBT; or (2) MHFA alone, and complete 3 online surveys at baseline, 2- and 6-months. Primary outcomes will be measured in the business advisors and consist of the quality of the relationship, stigmatizing attitude, confidence to offer mental health first aid, quality of life and provision of mental health first aid. Secondary outcomes will be measured in the SME owners and includes trust in their business advisors, the quality of this relationship, financial wellbeing, financial distress, psychological distress, help-seeking behaviour, and quality of life. To complement the quantitative data, we will include a qualitative process evaluation to examine what contextual factors impacted the reach, effectiveness, adoption, implementation, and maintenance of the training. DISCUSSION: As there is evidence for the connections between client trust, quality of relationship and financial and mental wellbeing, we hypothesise that the combined RBT and MHFA training will lead to greater improvements in these outcomes in SME owners compared with MHFA alone. TRIAL REGISTRATION: ClinicalTrials.gov : NCT04982094 . Retrospectively registered 29/07/2021. The study started in February 2021 and the recruitment is ongoing.

Variations of the cerebral arterial circle: morphological and clinical analysis / Variaciones del círculo arterial cerebral: análisis morfológico y clínico

SUMMARY: The variations knowledge of the cerebral arterial circle (CAC) is relevant due to its influence on the development of ischemic encephalic disorders. Among these variations, when the external diameter of the posterior communicating artery exceeds the posterior cerebral artery caliber, we have a fetal conformation of this circle. The aim of this study was to describe the variations of the CAC in Chilean individuals and to know the type of arterial conformation. Thirty adult brains were used to measure lengths and caliber of the pre-communicating segments of the anterior (A1) and posterior (P1) cerebral arteries, and the anterior (ACoA) and posterior (PCoA) communicating arteries. The arterial conformation type was established, and the length and caliber of these vessels were compared according to the right or left side. It was observed that 76.6 % of the CACs presented aplasia and / or hypoplasia. Of its components, PCoA was hypoplasic in 53.3 %, appearing bilaterally in 40 % of the subjects. The comparison according to the side, indicated that the mean length of A1 and PCoA on the right side was slightly higher. In the case of caliber, the mean of A1, P1 and PCoA was higher on the left side. Regarding P1 and PcoA caliber, 33 % of the CACs presented unilateral fetal conformation. Regardless of the variability presented by the CAC, there is consensus that PCoA exhibits the greatest variability. The understanding of this variability requires an analysis of the embryonic aspects that can explain the fetal conformation of the CAC in the adult.

RESUMEN: El conocimiento de las variaciones del círculo arterial cerebral (CAC) resultan relevantes por su influencia en el desarrollo de trastornos isquémicos encefálicos. De estas variaciones, los cambios del calibre de la arteria comunicante posterior (ACoP) determinan una conformación fetal de este círculo. El objetivo de este estudio fue describir las variaciones del CAC en individuos chilenos y conocer el tipo de conformación arterial. Se utilizaron 30 encéfalos adultos a los que se midieron las longitudes y calibres de los segmentos precomunicante de las arterias cerebrales anteriores (A1) y posteriores (P1), y de las arterias comunicante anterior (ACoA) y ACoP. Se estableció el tipo de conformación arterial y se comparó la longitud y calibre de estos vasos según lateralidad. Se observó que el 76,6 % de los CAC presentaron agenesias y/o hipoplasias. De sus componentes, la ACoP fue hipoplásica en el 53,3 %, presentándose bilateral en el 40 %. La comparación según lateralidad indicó que la longitud media de A1 y ACoP del lado derecho fueron levemente superiores. En el caso de los calibres, la media de A1, P1 y ACoP fue superior en el lado izquierdo. Respecto de los calibres de P1 y ACoP, el 33 % de los CAC presentaron conformación fetal unilateral. Independientemente de la variabilidad que presenta el CAC, existe consenso de que la ACoP exhibe la mayor variabilidad. La comprensión de esta variabilidad requiere un análisis de los aspectos embrionarios que pueden explicar la conformación fetal de esté círculo arterial en el adulto.

Campaña de Protección Solar y Prevención del cáncer de piel en Farmacia Comunitaria, valoración de un nuevo servicio profesional / Sun Protection and Skin Cancer Prevention Campaign in Community Pharmacy, evaluation of a new professional service

JUSTIFICACIÓN: el cáncer de piel supone un problema de salud pública, cuya incidencia ha aumentado. El factor ambiental de mayor riesgo para ello es la exposición a la radiación ultravioleta. El farmacéutico comunitario (FC) es un profesional cualificado y formado para poder ayudar e indicar al paciente en la elección de su fotoprotector, así como, la galénica que mejor se adecúe a su tipo de piel. Además de realizar una tarea de prevención e información sobre los riesgos que implica la exposición solar.OBJETIVOS: •Valorar los conocimientos y el uso correcto de protectores solares por la población general. •Determinar el riesgo de padecer cáncer de piel (CP). •Valorar la necesidad de un servicio profesional farmacéutico (SPF) en prevención de CP.MATERIAL Y MÉTODOS: estudio multicéntrico descriptivo observacional transversal prospectivo a través de un cuestionario anónimo a toda la población mayor de 18 años que acudía a la farmacia comunitaria durante la semana del 14-19 de junio de 2021. En él, se recogieron datos demográficos, fototipo cutáneo, presencia de algún tipo de dermatosis, patología crónica, administración de algún medicamento fotosensibilizante, presencia de alguna lesión, criterios de derivación, factores de riesgo de CP, así como los conocimientos sobre protección solar.RESULTADOS: participaron un total de 17 FC realizando 147 encuestas, 73 % mujeres, el 41 % menor de 40 años. (AU)

Maximum in density of electrolyte solutions: Learning about ion-water interactions and testing the Madrid-2019 force field.

In this work, we studied the effect of Li+, Na+, K+, Mg2+, and Ca2+ chlorides and sulfates on the temperature of maximum density (TMD) of aqueous solutions at room pressure. Experiments at 1 molal salt concentration were carried out to determine the TMD of these solutions. We also performed molecular dynamics simulations to estimate the TMD at 1 and 2 m with the Madrid-2019 force field, which uses the TIP4P/2005 water model and scaled charges for the ions, finding an excellent agreement between experiment and simulation. All the salts studied in this work shift the TMD of the solution to lower temperatures and flatten the density vs temperature curves (when compared to pure water) with increasing salt concentration. The shift in the TMD depends strongly on the nature of the electrolyte. In order to explore this dependence, we have evaluated the contribution of each ion to the shift in the TMD concluding that Na+, Ca2+, and SO4 2- seem to induce the largest changes among the studied ions. The volume of the system has been analyzed for salts with the same anion and different cations. These curves provide insight into the effect of different ions upon the structure of water. We claim that the TMD of electrolyte solutions entails interesting physics regarding ion-water and water-water interactions and should, therefore, be considered as a test property when developing force fields for electrolytes. This matter has been rather unnoticed for almost a century now and we believe it is time to revisit it.

The Madrid-2019 force field for electrolytes in water using TIP4P/2005 and scaled charges: Extension to the ions F-, Br-, I-, Rb+, and Cs.

In this work, an extension of the Madrid-2019 force field is presented. We have added the cations Rb+ and Cs+ and the anions F-, Br-, and I-. These ions were the remaining alkaline and halogen ions, not previously considered in the Madrid-2019 force field. The force field, denoted as Madrid-2019-Extended, does not include polarizability and uses the TIP4P/2005 model of water and scaled charges for the ions. A charge of ±0.85e is assigned to monovalent ions. The force field developed provides an accurate description of aqueous solution densities over a wide range of concentrations up to the solubility limit of each salt studied. Good predictions of viscosity and diffusion coefficients are obtained for concentrations below 2 m. Structural properties obtained with this force field are also in reasonable agreement with the experiment. The number of contact ion pairs has been controlled to be low so as to avoid precipitation of the system at concentrations close to the experimental solubility limit. A comprehensive comparison of the performance for aqueous solutions of alkaline halides of force fields of electrolytes using scaled and integer charges is now possible. This comparison will help in the future to learn about the benefits and limitations of the use of scaled charges to describe electrolyte solutions.

Multidisciplinary consensus on the criteria for fertility preservation in cancer patients

Infertility is one of the main sequelae of cancer and its treatment in both children and adults of reproductive age. It is, therefore, essential that oncologists and haematologists provide adequate information about the risk of infertility and the possibilities for its preservation before starting treatment. Although many international clinical guidelines address this issue, this document is the first Spanish multidisciplinary guideline in paediatric and adult oncological patients. Experts from the Spanish Society of Medical Oncology, the Spanish Fertility Society, the Spanish Society of Haematology and Haemotherapy, the Spanish Society of Paediatric Haematology and Oncology and the Spanish Society of Radiation Oncology have collaborated to develop a multidisciplinary consensus.

On the thermodynamics of curved interfaces and the nucleation of hard spheres in a finite system.

We determine, for hard spheres, the Helmholtz free energy of a liquid that contains a solid cluster as a function of the size of the solid cluster by means of the formalism of the thermodynamics of curved interfaces. This is done at the constant total number of particles, volume, and temperature. We show that under certain conditions, one may have several local minima in the free energy profile, one for the homogeneous liquid and others for the spherical, cylindrical, and planar solid clusters surrounded by liquid. The variation of the interfacial free energy with the radius of the solid cluster and the distance between equimolar and tension surfaces are inputs from simulation results of nucleation studies. This is possible because stable solid clusters in the canonical ensemble become critical in the isothermal-isobaric ensemble. At each local minimum, we find no difference in chemical potential between the phases. At local maxima, we also find equal chemical potential, albeit in this case the nucleus is unstable. Moreover, the theory allows us to describe the stable solid clusters found in simulations. Therefore, we can use it for any combination of the total number of particles, volume, and global density as long as a minimum in the Helmholtz free energy occurs. We also study under which conditions the absolute minimum in the free energy corresponds to a homogeneous liquid or to a heterogeneous system having either spherical, cylindrical, or planar geometry. This work shows that the thermodynamics of curved interfaces at equilibrium can be used to describe nucleation.

Perceptions from nurses, surgeons, and anesthetists about the use and benefits of the surgical checklist in a teaching hospital.

OBJECTIVE: To assess attitudes and perceptions from nursing staff, surgeons and anesthetists about compliance, utility, and impact on patient's safety of the surgical checklist in a teaching hospital. We also aimed to identify improvement opportunities for strengthening the usefulness of the checklist in the operating theater. METHODS: We carried out a questionnaire-based an observational cross-sectional study. A questionnaire was distributed to operating room staff, including nursing staff, surgeons, and anesthetists. In addition to the information about surgical checklist, We also collected information regarding years of experience in the operating theater. Fisher's exact was used to compare proportions in each statement. Group discussion meetings with key professionals were held to jointly assess the results, propose improvement actions, and evaluate their feasibility. RESULTS: The overall response rate was 36.2% (131/362). Nursing staff was perceived as the most supportive group in the use of surgical checklist. A 64.3% of surgeons considered that using the checklist prevented adverse events vs 84.2% and 85.7% among anesthetists and nurses, respectively; p=0.028. Junior staff showed a supportive attitude toward the use of surgical checklist, considering it as a tool that gives them confidence. We ended up with a list of improvement actions aiming at strengthening the surgical checklist reliability and compliance. CONCLUSIONS: The perception of the surgical checklist usefulness as a tool to prevent adverse events was moderate among surgeons, but well appreciated by junior staff. Nursing staff were especially critical regarding compliance and support by other professionals. To reinforce the usefulness perception of the surgical checklist it is needed to increase the involvement of all professionals, especially senior staff and surgical leaders.

Multidisciplinary consensus on the criteria for fertility preservation in cancer patients.

Infertility is one of the main sequelae of cancer and its treatment in both children and adults of reproductive age. It is, therefore, essential that oncologists and haematologists provide adequate information about the risk of infertility and the possibilities for its preservation before starting treatment. Although many international clinical guidelines address this issue, this document is the first Spanish multidisciplinary guideline in paediatric and adult oncological patients. Experts from the Spanish Society of Medical Oncology, the Spanish Fertility Society, the Spanish Society of Haematology and Haemotherapy, the Spanish Society of Paediatric Haematology and Oncology and the Spanish Society of Radiation Oncology have collaborated to develop a multidisciplinary consensus.

Homogeneous nucleation of NaCl in supersaturated solutions.

The seeding method is an approximate approach to investigate nucleation that combines molecular dynamics simulations with classical nucleation theory. Recently, this technique has been successfully implemented in a broad range of nucleation studies. However, its accuracy is subject to the arbitrary choice of the order parameter threshold used to distinguish liquid-like from solid-like molecules. We revisit here the crystallization of NaCl from a supersaturated brine solution and show that consistency between seeding and rigorous methods, like Forward Flux Sampling (from previous work) or spontaneous crystallization (from this work), is achieved by following a mislabelling criterion to select such threshold (i.e. equaling the fraction of the mislabelled particles in the bulk parent and nucleating phases). This work supports the use of seeding to obtain fast and reasonably accurate nucleation rate estimates and the mislabelling criterion as one giving the relevant cluster size for classical nucleation theory in crystallization studies.

Nanocomposite PLA/C20A Nanoclay by Ultrasound-Assisted Melt Extrusion for Adsorption of Uremic Toxins and Methylene Blue Dye.

Design of functional materials it is of great importance to address important problems in the areas of health and environment. In the present work, the synthesis and application of poly-meric nanocomposite materials with poly (lactic acid) (PLA) and modified nanoclay (cloisite 20A) with 1,4-diaminobutane dihydrochloride at different reaction times were studied. The concentra-tions of the nanoclays in the PLA matrix were 0.5, 1 and, 5% by weight (wt%). TGA showed that sample C20AM 120 (120 min of treatment) obtained the highest degree of modification considering the weight losses of the analyzed samples. An FT-IR signal at 1443 cm-1 suggests that the organic modifier is intercalated between the galleries of the clay. XRD, SEM and XPS suggest good disper-sion at low concentrations of the nanoclay. Adsorption tests revealed that the highest percentage of removal of uremic toxins and methylene blue was the sample with 5% wt/wt chemically modified nanoclay, suggesting good affinity between the modified nanoclays in the PLA matrix with the nitrogenous compounds.

Isotopic evolution of planetary crusts by hypervelocity impacts evidenced by Fe in microtektites.

Fractionation effects related to evaporation and condensation had a major impact on the current elemental and isotopic composition of the Solar System. Although isotopic fractionation of moderately volatile elements has been observed in tektites due to impact heating, the exact nature of the processes taking place during hypervelocity impacts remains poorly understood. By studying Fe in microtektites, here we show that impact events do not simply lead to melting, melt expulsion and evaporation, but involve a convoluted sequence of processes including condensation, variable degrees of mixing between isotopically distinct reservoirs and ablative evaporation during atmospheric re-entry. Hypervelocity impacts can as such not only generate isotopically heavy, but also isotopically light ejecta, with δ56/54Fe spanning over nearly 5‰ and likely even larger variations for more volatile elements. The mechanisms demonstrated here for terrestrial impact ejecta modify our understanding of the effects of impact processing on the isotopic evolution of planetary crusts.