ABSTRACT The COVID-19 pandemic brought with it the use of personal protective equipment; mainly face masks. The large number of face masks are used daily, and their inadequate final disposal has turned them into an environmental problem. The goal of this research is to determine the amount of face mask waste as an environmental contaminant. By collecting such waste in five tourist sites (urban, beach, and lake) in Nayarit, Mexico, during five months of the years 2021 and 2022. A greater presence of this type of waste was found during the year 2022. More adult mouth covers prevailed than infant mouth covers. Finally, urban areas showed a higher density of face masks than the rest of the analyzed areas. It is concluded that it is necessary for adequate measures to be implemented for the correct disposal of the waste generated with the pandemic.

RESUMEN La pandemia de COVID-19 trajo consigo el uso de equipo de protección personal, principalmente cubrebocas. La gran cantidad de ellos que se utilizaron diariamente y su inadecuada disposición final, los han convertido un problema ambiental. El objetivo de esta investigación fue determinar la presencia de residuos de cubrebocas como contaminantes ambientales. Mediante la recolección de dichos residuos, en cinco sitios turísticos (urbanos, de playa y un lago) de Nayarit, México, durante cinco meses de los años 2021 y 2022. Se obtuvo mayor presencia de este tipo de residuos durante el año 2022. Prevalecieron más los cubrebocas utilizados por adultos que por infantes. Finalmente, las zonas urbanas mostraron una mayor densidad de cubrebocas que el resto de las zonas analizadas. Se concluye que es necesario que se implementen medidas adecuadas para la correcta disposición de los residuos generados con la pandemia.

Abstract Antimony doped tin oxide (ATO) thin films are deposited on corning glass substrate using the spray pyrolysis technique. The experimental parameters such as distance between the substrate and source (10-30 cm), substrate temperature (350-450°C) and atmospheres (Nitrogen and Forming gas) are varied to study their effect on the properties of ATO thin films. The ATO thin film annealed at 425°C exhibits the lowest electrical resistivity of 2.23×10-2 Ω-cm. Besides, the film annealed in the nitrogen atmosphere showed a less resistivity value of 9.06×10-3 (Ω-cm) than the forming gas atmosphere. The film doped with 3 at% of Sb revealed the highest figure of merit value of 11.45x10-2 Ω-1. The preferential orientation is observed at the (200) diffraction plane in all the cases from the structural studies. Furthermore, the intensity of the diffraction planes decreases as the temperature increases. The average transmittance of 75% is obtained for ATO thin films.

Abstract Inverted organic photovoltaic solar cells were fabricated with the configuration of FTO/TiO2/P3HT:PC61BM/MoO3/Ag. Besides, the influence of transport layers, titanium dioxide and molybdenum trioxide, on the performance of solar cells were investigated. These compounds showed excellent optical (around 80% for molybdenum trioxide and 95% for titanium dioxide), electrical (like charge carrier density of 3.3 x1015 cm-3 and 2.5 x1014 cm-3 for titanium and molybdenum, respectively) and structural (anatase and amorphous hexagonal phase for titanium and molybdenum, respectively) properties to be used as transport layers. Also the influence of the thickness of the electron transport layer is studied, as well as the thickness, temperature and heat treatment time of the active layer. The correct selection of TiO2’s thickness (70 nm) and active layer’s thickness (250 nm) and annealing (at 100 degrees for 8 minutes) can increase the power conversion efficiency. Moreover, the cell fabricated with transport layers and the best conditions found showed a maximum efficiency of 3.3%, which indicates that the titanium dioxide and molybdenum trioxide played a determining role in the solar cell performance.

Abstract Bismuth (III) sulfide thin films are prepared on glass substrates by physical vapor deposition technique. Then, the films are annealed at different temperatures from 150 to 350°C with nitrogen and nitrogen-sulfur atmospheres, respectively. The effect of annealing temperature on the optoelectronic properties is investigated. The layers were characterized using ultraviolet-visible spectroscopy, XRD, Raman spectroscopy, EDS analysis and Hall effect. The film annealed at 250°C in a nitrogen-sulfur atmosphere exhibited the best condition with an initial thickness of 106 nm and band gap of 1.37 eV. Also, Bismuthinite phase was obtained, close to the stoichiometry with 59.95 and 40.05 at % for bismuth and sulfur, respectively. The charge carrier concentration of 6.9x1019 cm-3 with a n-type conductivity, the resistivity of 0.19 Ω-cm, and mobility of 0.44 cm2V-1s-1 are obtained.

Abstract Crops belonging to the genus Allium, family Amaryllidaceae, are economically important and are widely cultivated around the globe. Some of the most problematic diseases of these crops are caused by members of three virus genera, Potyvirus, Carlavirus and Allexivirus. Shallot virus X (ShVX) is an Allexivirus that was first discovered in Russia in the nineties and it has since been described worldwide. The virus, transmitted mechanically or by the dry bulb mite (Aceria tulipae), affects virtually all members of the genus Allium and it causes yield reductions on these crops. ShVX is a positive-sense single-stranded monopartite RNA virus that contains six open reading frames (ORFs). The virus is mainly detected by RT-PCR but there are other serological and molecular techniques available for diagnosis. There are no methods described for managing crops infected by ShVX in the field, but tissue culture of meristems can render virus-free plants. Research on the ShVX-Allium pathosystem is needed for a comprehensive understanding of the physiological and molecular mechanisms used by the virus to infect its hosts and for developing methods for the effective control of viral infections.

Resumen Los cultivos del género Allium, familia Amaryllidaceae, son económicamente importantes y ampliamente sembrados alrededor del mundo. Algunas de las enfermedades más problemáticas de estos cultivos son ocasionadas por virus de tres géneros, Potyvirus, Carlavirus y Allexivirus. Shallot virus X (ShVX) es un Allexivirus que fue descrito por primera vez en Rusia en la década de los noventa y desde entonces se ha descrito su presencia a nivel mundial. El virus, transmitido mecánicamente o por el eriófido de los bulbos (Aceria tulipae), afecta prácticamente a todos los miembros del género Allium ocasionando la disminución en la producción de estos cultivos. ShVX tiene un genoma monopartito representado por una cadena simple de ARN de polaridad positiva con seis marcos abiertos de lectura (ORFs). El virus se detecta principalmente por RT-PCR, pero existen otros métodos serológicos y moleculares disponibles para su diagnóstico. No existen métodos descritos para el manejo de plantas infectadas con ShVX en el campo, sin embargo se ha determinado que el cultivo de tejidos meristemáticos puede producir plantas libres de virus. Es necesario desarrollar investigaciones en el patosistema ShVX-Allium para lograr un entendimiento general sobre los mecanismos fisiológicos y moleculares que utiliza el virus para infectar a su hospedero y para desarrollar métodos para el control efectivo de las infecciones virales.

Resumen: En Chile, la Escala de Evaluación del Desarrollo Psicomotor (EEDP) y Test de Desarrollo Psicomotor (TEPSI) son herramientas no actualizadas, que carecen de confiabilidad y validación internacional conocida; por ello se hace necesario analizar el proceso evaluativo desde los actores de salud y educación, Enfermeras y Educadoras de párvulos respectivamente. El objetivo fue develar las vivencias de estos actores sociales, partícipes en el proceso evaluativo del desarrollo psicomotor en menores de tres años, según determinantes sociales. Se trata de un estudio cualitativo exploratorio, basado en la fenomenología de Alfred Schütz, realizado en siete informantes claves, cinco enfermeras y dos educadoras de párvulos, por medio de la entrevista semiestructurada. El análisis se circunscribió a transcripción, codificación, agrupamiento en categorías y síntesis. Se develan las metacategorías: A: Dilemas e incertidumbres por nudos críticos y categorías intermedias: a) Brecha entre políticas públicas y realidad local, no favorece el desarrollo de los niños, b) Instrumentos desactualizados y descontextualizados, c) Mitos y expectativas de los padres frente a la evaluación, d) Instrumentos sin pertinencia social; y B: Expectativas y categorías intermedias: a) Actualización del marco político para un avance continuo y efectivo, b) Incorporación y empoderamiento de los padres en el proceso, c) Capacitación y perfeccionamiento de profesionales. Se concluye que es necesario la actualización de las estrategias evaluativas y disponer de instrumentos validados, actualizados, con pertinencia social y que consideren a los padres

Abstract: In Chile, the Psychomotor Development Evaluation Scale (EEDP in Spanish) and the Psychomotor Development Test (TEPSI in Spanish) are outdated tools that lack international reliability and validation. It is necessary to analyze the evaluation process from the point of view of the health and education professionals, that is, nurses and early childhood educators. The purpose was to reveal the experiences of these actors in the evaluation process of psychomotor development in children under three years of age, according to social determinants. This is a qualitative exploratory study based on the Alfred Schütz phenomenology, carried out in seven key informants, five nurses and two educators, through semi-structured interviews. The analysis was limited to transcription, coding, grouping into categories and synthesis. The meta categories revealed are: A: Dilemmas and uncertainties by critical nodes and intermediate categories: a) The gap between public policies and local reality does not favor the development of children, b) Outdated and decontextualized instruments, c) Myths and expectations of the parents regarding the evaluation, d) Instruments without social relevance; and B: Expectations and intermediate categories: a) Political framework update for continuous and effective progress, b) Parents incorporation and empowerment in the process, c) Professionals training and improvement. It was concluded that it is necessary to update the evaluation strategies and have validated, updated and socially relevant instruments that include the parents

Resumo: No Chile, as Escala de Avaliação do Desenvolvimento Psicomotor (EEDP) e Teste de Desenvolvimento Psicomotor (TEPSI) não são ferramentas atualizadas, que carecem de confiabilidade e validação internacionalmente conhecidas, por essa razão, é necessário analisar o processo de avaliação dos atores de saúde e educação, enfermeiros e educadoras de creches, respectivamente. Lo objetivo foi revelar as experiências dos atores sociais participantes, enfermeiros e educadoras de creches, no processo de avaliação do desenvolvimento psicomotor em crianças menores de 3 anos, segundo os determinantes sociais. Foi realizado um estudo qualitativo exploratório baseado na fenomenologia de Alfred Schütz, realizado em 7 informantes-chave, 5 enfermeiros e 2 educadoras de creches, por meio de entrevista semiestruturado. A análise foi limitada à transcrição; codificação; agrupamento em categorias e síntese. Dilemas e incertezas de nós críticos e categorias intermediárias: a) lacuna entre política pública e da realidade local, não favorece o desenvolvimento das crianças, b) instrumentos desatualizados e, c) Mitos descontextualizadas e expectativas dos metacategorias são revelados os pais na frente da avaliação, d) Instrumentos sem relevância social; e B: Expectativas e categorias intermediárias: a) Atualização do arcabouço político para o progresso contínuo e efetivo, b) Incorporação e empoderamento dos pais no processo, c) Treinamento e aperfeiçoamento dos profissionais. É necessário atualizar as estratégias de avaliação e validar instrumentos atualizados e de relevância social que considerem os pais

Resumo Introdução Quando se utilizem questionários desenvolvidos em outros países e idiomas em estudos científicos, além de traduzi-los, é necessário sua adaptação cultural e validação, o objetivo desta pesquisa é contar com um instrumento válido e confiável para avaliar as competências do pessoal de enfermagem em saúde pública, para aplicá-lo no contexto mexicano. Metodologia O estudo foi de tipo descritivo-transversal, multietápico, a população integrou-se em 3 grupos para as 3 diferentes etapas, na primeira, por um grupo de 10 experientes na pesquisa da Faculdade de Enfermagem de Tampico, da Universidad Autónoma de Tamaulipas, México e 17 profissionais que laboram no primeiro nível de atenção; na segunda, 30 profissionais de enfermagem e na terceira 177 profissionais que trabalham no campo da saúde pública, todos eles de três jurisdições do Sul de Tamaulipas, México, a amostra foi por conveniência. Resultados Em referência aos três processos que se realizaram para a validação do instrumento, mostraram-se resultados adequados e satisfatórios para sua aplicação, já que na prova de V-Aiken obteve-se um resultado próximo a 1, no processo semântico só se realizou modificação a una palavra; a través da prova piloto obteve-se um resultado de 0.97 na alfa de cronbach. Conclusões O instrumento considera-se válido para iniciar com a avaliação das mencionadas competências, para contar com um diagnóstico inicial das áreas de oportunidade para pessoal de enfermagem.

Abstract Introduction When using questionnaires developed in other countries and languages for scientific studies, besides the translation, it is necessary their cultural adaptation and validation. The objective of this work was to assure the use of an instrument which is valid and reliable while assessing the competencies among nursing personnel of public health in the Mexican context. Methodology This is a descriptive-transversal and multi-step study. The population was represented by 3 groups for 3 different stages. The first group was integrated by 10 experts in research from the Nursing Faculty of the University of Tamaulipas, Tampico, and 17 professionals working in the first level of attention. The second group was integrated by 30 professionals of nursing. The third group was integrated by 177 professionals working in the field of public health. All professionals were from three jurisdictions in the south of Tamaulipas, Mexico. The sampling process was by convenience. Results The three validation processes showed satisfactory results for the adaptation of the instrument. The V-Aiken test score was close to 1. Regarding the semantics, only one word was modified. The pilot test had a final Cronbach Alpha of 0.97. Conclusions The instrument was considered valid for the assessment of the herein referenced competencies.

Resumen Introducción Cuando se utilicen cuestionarios desarrollados en otros países e idiomas en estudios científicos, además de traducirlos, es necesario su adaptación cultural y validación, el objetivo de esta investigación es contar con un instrumento válido y confiable para evaluar las competencias del personal de enfermería en salud pública, para aplicarlo en el contexto mexicano. Metodología El estudio fue de tipo descriptivo-transversal, multietápico, la población se integró en 3 grupos para las 3 diferentes etapas, en la primera, por un grupo de 10 expertos en investigación de la Facultad de Enfermería de Tampico, de la Universidad Autónoma de Tamaulipas, México y 17 profesionales que laboran en el primer nivel de atención; en la segunda, 30 profesionales de enfermería y en la tercera 177 profesionales que trabajan en el campo de la salud pública, todos ellos de tres jurisdicciones del Sur de Tamaulipas, México, el muestreo fue por conveniencia. Resultados En cuanto a los tres procesos que se realizaron para la validación del instrumento, se mostraron resultados adecuados y satisfactorios para su aplicación, ya que en la prueba de V-Aiken se obtuvo un resultado cercano a 1, en el proceso semántico sólo se realizó modificación a una palabra; a través de la prueba piloto se obtuvo un resultado de 0.97 en el Alfa de Cronbach. Conclusiones El instrumento se considera válido para iniciar con la evaluación de las mencionadas competencias, para contar con un diagnóstico inicial de las áreas de oportunidad para personal de enfermería.

Abstract Cadmium telluride (CdTe) nanoparticles were grown in the interior of a SnO2 transparent matrix by means of the r.f. sputtering technique. X-ray diffraction (XRD) patterns reveal that the CdTe quantum dots (QD) grow in the hexagonal wurtzite (W) phase. Diffraction data show that SnO2 is constituted by nanoparticles also, with size of the same order of the W-CdTe QD. The broad bands of the XRD patterns and the Scherrer formula allowed, by assuming a spherical shape, the W-CdTe QD size calculation, which have average diameters in the range 4.8 - 14.0 nm. These data were confirmed by electron microscopy images. Optical absorbance gives information to calculate the energy of the two lowest excitonic states (band gap). The Raman spectra show several broad bands in the range 100 - 200 cm-1, on which deconvolution allows separate five modes in the 100 - 200 cm-1 interval. The bands correspond to CdTe and tetragonal Te. The transversal optic (TO) and longitudinal optic (LO) modes of CdTe at the Γ point of the first Brillouin zone, for phonons in nanoparticles, follow the expected behavior if the radius of crystal decreases, taking into account that the selection rules for momentum conservation are relaxed.

Abstract BACKGROUND: Loxoscelism is a poisoning caused by the bite of Loxosceles recluse spider, whose venom contains sphingomyelinaseD, causing hemolysis and necrosis. We report a case series describing their clinical course and response to treatment. OBJECTIVE: To describe the evolution and clinical characteristics of patients with systemic and dermonecrotic loxoscelism, their response to treatment and complications. PATIENTS AND METHOD: A descriptive analysis of patients treated in the Internal Medicine Service, Centro Médico Nacional La Raza, from 2010 to 2015. RESULTS: A total of 8 men (67%) and 4 women (33%) were included. Mean age was 39.4 years (16-83 years). Bite site was left pelvic limb in 5 cases (42%), 4 in the right forelimb (33%), 2 in the face (17%) and 1 in left forelimb (9%). Nine cases came from Estado de México, 2 from Mexico City and 1 from Hidalgo. Initial manifestations included blisters (five cases), edema and erythema (three cases), liveloide plate (three cases) and necrosis (one case). Nine (75%) patients were initially managed in ICU. Systemic complications were renal (67%), lung with use of amines (33%) and hematological (8%). Ten cases were treated with fabotherapy, with an average of 1.5 vials (0-4). Five cases (42%) received dapsone and 4 of them (33%) developed methemoglobinemia. Eleven (92%) required surgical washing and debridement and 7 (58%) skin graft; four patients (33%) had secondary wound infection. Average hospital stay was 16.2 days (3-40 days). CONCLUSIONS: The evolution and prognosis depends on initial suspicion early diagnosis and treatment. Loxoscelism should be included in the differential diagnosis of progressive necrotic lesions, with or without systemic involvement.

Resumen ANTECEDENTES: el loxoscelismo es una intoxicación por la mordedura de la araña Loxosceles reclusa, cuyo veneno contiene esfingomielinasa-D, causante de hemólisis y necrosis. Se reporta una serie de casos que describen su evolución clínica y respuesta al tratamiento. OBJETIVO: describir la evolución y características clínicas de pacientes con loxoscelismo sistémico y dermonecrótico, su respuesta al tratamiento y las complicaciones. PACIENTES Y MÉTODO: estudio que incluyó el análisis descriptivo de pacientes tratados en el servicio de Medicina Interna, Unidad Médica de Alta Especialidad Dr. Antonio Fraga Mouret, Centro Médico Nacional La Raza, de 2010 a 2015. RESULTADOS: se atendieron ocho hombres (67%) y cuatro mujeres (33%), con edad media de 39.4 años (16-83 años). El sitio de mordedura en cinco casos (42%) fue el miembro pélvico izquierdo; cuatro casos en el miembro torácico derecho (33%), dos en la cara (17%) y uno en el miembro torácico izquierdo (9%). Nueve casos provenían del Estado de México, dos de la Ciudad de México y uno de Hidalgo. Manifestación clínica: flictenas (cinco casos), edema y eritema (tres), placa liveloide (tres) y necrosis (un caso). Nueve (75%) pacientes se trataron inicialmente en la unidad de cuidados intensivos. Se reportaron las siguientes complicaciones sistémicas: renales (67%), pulmonares con administración de aminas (33%) y hematológicas (8%). Diez casos recibieron faboterápico, con media de 1.5 viales (0 a 4); cinco casos (42%) recibieron dapsona y cuatro de ellos (33%) padecieron metahemoglobinemia; once (92%) pacientes requirieron lavado-desbridación y 7 (58%) injerto cutáneo; cuatro pacientes (33%) tuvieron infección agregada de la herida. El promedio de estancia hospitalaria fue 16.2 días (3 a 40 días). CONCLUSIÓN: la evolución y pronóstico de esta afección depende de una sospecha inicial, diagnóstico y tratamiento oportunos. El loxoscelismo debe incluirse en los diagnósticos diferenciales de lesiones necróticas y progresivas, con o sin afección sistémica.

ABSTRACT Embryo thermal stimulation has been studied as a means to promote epigenetic changes and to improve broiler health and performance. This study aimed at evaluating immunoglobulin (IgM, IgG, and IgA) titers, serum corticosterone levels, and organ integrity of day-old male Cobb(r) and Ross(r) broilers. Embryos were submitted to hot and cold stimuli (thermal stimulation) on days 14-18 of incubation. The thermal manipulation treatments did not affect immunoglobulin titers of 1 day-old Cobb(r) or Ross(r) chicks, and caused severe bursal lesions (scores 3 and 4) in both strains. However, serum corticosterone levels of Cobb(r) chicks were higher when embryos were submitted to hot stimulus (+1.39ºC) compared with cold stimulus (+36 ºC). Serum corticosterone levels of Ross(r) chicks were not affected by embryo temperature manipulation. The only effect of broiler breeder age was observed on IgM titers of Cobb(r) chicks, which were higher in chicks from 33-wk-old breeders. Further studies are needed to detect the optimal period of embryo thermal stimulation.

Abstract In this work, the fabrication of bottom-gate TFTs with unplanarized and planarized gate electrode are reported, as well simulations of the impact of the gate planarization in the TFTs are presented. Previously in literature, a reduction of the contact resistance has been attributed to this planarized structure. In order to provide a physical explanation of this improvement, the electrical performance of ambipolar a-SiGe:H TFTs with planarized gate electrode by Spin-On Glass is compared with unplanarized ambipolar a-SiGe:H TFTs. Then, the properties in the main device interfaces are analyzed by physically-based simulations. The planarized TFTs have better characteristics such as field-effect mobility, on-current, threshold voltage and on/off-current ratio which are consequence of the improved contact resistance.

Abstract: A productive socio-productive profile of people in 14 communities in Veracruz, Mexico, was characterized to identify their current status, local resources, management and identification of value chains through participatory forums. The main activity of communities is to growing coffee, wich they consider bad business, as such have developed a partnership with ornamental species to improve income. The age of the 56% of actors ranging between 50 to 90 years, have low educational level, not partner to the work, marketed through intermediaries and are considered in poverty. Female gender participation is 30%, there is no generational scheme in the transition for young people, 46% obtained the knowledge of local resource use from grandfather-father-son, 76.4% obtained seed from the own plots and considered viable generate new value networks.

Resumen: Se caracterizó el perfil socio-económico-productivo de habitantes de 14 comunidades en Veracruz, México, para identificar su condición actual, recursos locales y manejo e identificación de eslabones de valor mediante foros participativos. La actividad principal de las comunidades es el cultivo de café, que consideran mal negocio, por tal motivo han desarrollado una asociación con especies ornamentales para mejorar sus ingresos. La edad del 56% de los actores oscila entre 50 y 90 años, tienen bajo nivel escolar, no se asocian para el trabajo, comercializan a través de intermediarios y se consideran en condición de pobreza. La participación de género femenino es del 30%, no existe esquema de relevo generacional para jóvenes, 46% obtuvo el conocimiento de uso del recurso local de abuelo-padre-hijo, 76.4% obtiene semilla de las propias parcelas y consideran viable generar nuevas redes de valor.

With the purpose of knowing the trophic resources used by Plebeia intermedia, a stingless bee of frequent use in Baritú locality (22° 28’ 54.1” S; 64° 45’ 39.4” W; at 1546 masl), ten honey samples were melissopalynologically analyzed, collected in September and October of 2011 and in January of 2012. The qualitative examinations showed a certain specialization of these bees for using native and arboreal plants, and with flowers clustered in dense inflorescences (mass flowering). The dominant pollen types that originated monofloral honeys were Allophylus edulis (Sapindaceae), Blepharocalyx salicifolius (Myrtaceae) and Myrcianthes pseudomato (Myrtaceae), followed by Handroanthus ochraceus (Bignoniaceae), Ilex argentina (Aquifoliaceae), Parapiptadenia excelsa (Leguminosae) and Sambucus peruviana (Adoxaceae). Other pollen types observed in the samples, with frequency classes important minor or secondary, were Eupatorium (Compositae), Senecio (Compositae), Paullinia (Sapindaceae) and pollens of the families Boraginaceae and Rhamnaceae. The realized examinations in the honeys of Plebeia intermedia and results obtained in this study, constitute the first data on the trophic resources used by this species of stingless bee in the period spring - summer.

Con la finalidad de conocer los recursos tróficos utilizados por Plebeia intermedia, una melipona de uso frecuente en la localidad de Baritú (22° 28’ 54,1” S; 64° 45’ 39,4” O; 1546 msnm), se efectuó el análisis polínico de diez muestras de miel colectadas en septiembre y octubre de 2011 y enero de 2012. Los exámenes cualitativos revelaron una cierta especialización de estas abejas por utilizar plantas nativas, de hábito arbóreo y con flores reunidas en inflorescencias abundantes (floraciones en masa). Los tipos polínicos dominantes presentes en las mieles monoflorales corresponden a las especies arbóreas Allophylus edulis (Sapindaceae), Blepharocalyx salicifolius (Myrtaceae) y Myrcianthes pseudomato (Myrtaceae), seguidos por Handroanthus ochraceus (Bignoniaceae), Ilex argentina (Aquifoliaceae), Parapiptadenia excelsa (Leguminosae) y Sambucus peruviana (Adoxaceae). Otros tipos polínicos observados en las muestras, con clases de frecuencia de menor importancia o secundario, fueron Eupatorium (Compositae), Senecio (Compositae), Paullinia (Sapindaceae) y pólenes de las familias Boraginaceae y Rhamnaceae. Los análisis efectuados en las mieles de Plebeia intermedia y los resultados obtenidos en este estudio, constituyen los primeros datos sobre los recursos tróficos utilizados por esta especie de melipona en el período primavera - verano.

Cadmium peroxide films were grown by chemical bath deposition on glass slides at 50 °C using CdCl2 as cadmium source. Films were deposited at different nominal cadmium concentrations. As-grown films were annealed in air at 300 °C for obtaining cadmium oxide thin films. The structural, morphological, optical and compositional properties of CdO films were analyzed in terms of the cadmium nominal composition and the annealing effect.

Objective: Understanding the mechanical properties of dental materials is essential for proper indication and a correct functioning in the oral cavity, as it allows the dentist to choose the material that presents better performance during mastication. The aim of this study was to evaluate the compressive strength of Ionofil Molar and Vitremer, according to the exposure time in artificial saliva. Materials: 5 samples were prepared for each material evaluated at 0, 168 and 504 hours in artificial saliva at 37º Celsius, according to the specifications suggested by ANSI/ADA specification No 66. The compressive strength was determined by subjecting the samples to an Instron strength-testing machine at a load speed of 1 mm/min. A test of homogeneity of variance was conducted; normality was determined by Kolmogorov-Smirnov, and ANOVA. Tukey’s test was performed to determine if significant differences existed between variables. Results: Vitremer compressive strength did not show statistically significant differences over time (p=0.282), unlike Ionofil Molar, which did present differences between times (p=0.011). Besides, there were no statistically significant differences in the samples without submerging (p=0.091), unlike after one to three weeks of exposure, were a difference did exist (p=0). Conclusion: Vitremer has greater compressive strength over time, without showing significant changes in time after being immersed in saliva, unlike Ionofil Molar, whose resistance decreased significantly under the same conditions.

Objetivo: El conocimiento sobre las propiedades mecánicas de los materiales dentales es fundamental para una correcta indicación y funcionamiento en la cavidad oral, permitiéndole al profesional optar por el que presente mejor comportamiento durante la masticación. El objetivo de este estudio fue evaluar la resistencia a la compresión de Ionofil Molar® y Vitremer®, según tiempo de exposición en saliva artificial. Materiales y Métodos: Se prepararon 5 muestras para cada material evaluadas a los tiempos 0, 168 y 504 horas en saliva artificial a 37° C, según las especificaciones propuestas por la norma ANSI/ADA n°66. La resistencia a la compresión se determinó sometiendo las muestras a cargas en un equipo de ensayo de fuerzas Instron® a una velocidad de carga de 1 mm/min. Se realizó una prueba de homogeneidad de varianzas, la normalidad se determinó mediante Kolmogorov-Smirnov, y posteriormente un ANOVA. Se realizó el test de Tukey para determinar si existió diferencia significativa entre variables. Resultados: La resistencia compresiva de Vitremer no presentó diferencias estadísticamente significativas en el tiempo (p=0.282), a diferencia de Ionofil Molar, que sí presentó diferencias entre los distintos tiempos (p=0.011). Además en las muestras sin sumergir, no hubo diferencia estadísticamente significativa entre materiales (p=0.091), en cambio sí existió diferencia al cabo de una y tres semanas de exposición (p=0). Conclusión: El vidrio ionómero Vitremer presenta mayor resistencia compresiva a lo largo del tiempo, sin presentar alteraciones significativas en el tiempo al ser inmerso en saliva, a diferencia del Ionofil Molar que disminuyó significativamente su resistencia en las mismas condiciones.