280 research outputs found

    Comparative study of hydrotalcite-derived supported Pd<sub>2</sub>Ga and PdZn intermetallic nanoparticles as methanol synthesis and methanol steam reforming catalysts

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    An effective and versatile synthetic approach to produce well-dispersed supported intermetallic nanoparticles is presented that allows a comparative study of the catalytic properties of different intermetallic phases while minimizing the influence of differences in preparation history. Supported PdZn, Pd2Ga, and Pd catalysts were synthesized by reductive decomposition of ternary Hydrotalcite-like compounds obtained by co-precipitation from aqueous solutions. The precursors and resulting catalysts were characterized by HRTEM, XRD, XAS, and CO-IR spectroscopy. The Pd2+ cations were found to be at least partially incorporated into the cationic slabs of the precursor. Full incorporation was confirmed for the PdZnAl-Hydrotalcite-like precursor. After reduction of Ga- and Zn-containing precursors, the intermetallic compounds Pd2Ga and PdZn were present in the form of nanoparticles with an average diameter of 6 nm or less. Tests of catalytic performance in methanol steam reforming and methanol synthesis from CO2 have shown that the presence of Zn and Ga improves the selectivity to CO2 and methanol, respectively. The catalysts containing intermetallic compounds were 100 and 200 times, respectively, more active for methanol synthesis than the monometallic Pd catalyst. The beneficial effect of Ga in the active phase was found to be more pronounced in methanol synthesis compared with steam reforming of methanol, which is likely related to insufficient stability of the reduced Ga species in the more oxidizing feed of the latter reaction. Although the intermetallic catalysts were in general less active than a Cu-/ZnO-based material prepared by a similar procedure, the marked changes in Pd reactivity upon formation of intermetallic compounds and to study the tunability of Pd-based catalysts for different reactions

    Foramen caróticoclinoideo en cráneos humanos: incidencia, morfometría y sus implicaciones clínicas

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    The caroticoclinoid foramen is an inconstant structure, formed by the union of the anterior and middle clinoid processes. The aim of this study was to perform an incidence and morphometry of the caroticoclinoid foramen in Brazilian human skulls and discuss its clinical implications. Eighty dry human skulls with sex distinction were used, and 3 groups of incidence were determined: General, sex, and sides. The morphometry was performed using a manual caliper and the major diameter of the foramina was measured; the values were also divided in general, according to sex and sides. The incidence of skulls with at least one foramen was 8.5%. According to the sides, 8.5% of the skulls showed foramen on the right side and 2.5% on the left. We found 2.5% of the skulls with bilateral foramen and 6.25% with unilateral foramen. In relation to sex, the foramens were found in 5% of male skulls and 12.5% of female skulls. The major diameter of this structure presented on mean, values of 5.23 mm on general, 5.18 mm on the right side and 5.35 mm on the left, 5.30 mm in male skulls and 5.18 mm in female skulls. The anatomical characteristics of this foramen should be considered in view of its clinical implications associated with neurosurgery as clinoid process removal, and symptoms as headache due to internal carotid artery alterations in this region. In conclusion knowledge of this structure supports the diagnosis and treatment of clinical complications related to this variation.The caroticoclinoid foramen is an inconstant structure, formed by the union of the anterior and middle clinoid processes. The aim of this study was to perform an incidence and morphometry of the caroticoclinoid foramen in Brazilian human skulls and discuss its clinical implications. Eighty dry human skulls with sex distinction were used, and 3 groups of incidence were determined: General, sex, and sides. The morphometry was performed using a manual caliper and the major diameter of the foramina was measured; the values were also divided in general, according to sex and sides. The incidence of skulls with at least one foramen was 8.5%. According to the sides, 8.5% of the skulls showed foramen on the right side and 2.5% on the left. We found 2.5% of the skulls with bilateral foramen and 6.25% with unilateral foramen. In relation to sex, the foramens were found in 5% of male skulls and 12.5% of female skulls. The major diameter of this structure presented on mean, values of 5.23 mm on general, 5.18 mm on the right side and 5.35 mm on the left, 5.30 mm in male skulls and 5.18 mm in female skulls. The anatomical characteristics of this foramen should be considered in view of its clinical implications associated with neurosurgery as clinoid process removal, and symptoms as headache due to internal carotid artery alterations in this region. In conclusion knowledge of this structure supports the diagnosis and treatment of clinical complications related to this variation292427431Das, S., Suri, R., Kapur, V., Ossification of caroticoclinoid ligament and its clinical importance in skull-based surgery (2007) São Paulo Med. J, 125, pp. 351-353Dodo, Y., Ishida, H., Incidence of nonmetric cranial variant in several population samples from East Asia and North America (1987) J. Anthrop. Soc. Nippon, 95, pp. 161-167Dolenc, V.V., A combined epi and subdural direct approach to carotidophthalmic artery aneurysms (1985) J. Neurosurg, 5, pp. 667-672Donald, P.J., (1998) Surgery of the Skull Base, , Philadelphia, Lippincott- RavenErturk, M., Kayalioglu, G., Govsa, F., Anatomy of the clinoidal region with special emphasis on the caroticoclinoid foramen and interclinoid osseous brid- ge in a recent Turkish population (2004) Neurosurg. Rev, pp. 22-26Gupta, N., Ray, B., Ghosh, S., A study on anterior clinoid process and optic strut with emphasis on variations of caroticoclinoid foramen (2005) Nep. Med. Coll. J, 7, pp. 140-144Hochstetter, F., Über die Taenia interclinoidea,die Commissura alicochlearis und die Cartilago supracochlearis des menschlichen Primordialkraniums.Gegenbaurs Morph (1940) Jahrb, 84, pp. 220-243Inoue, T., Rhoton Jr., A.L., Theele, D., Barry, M.E., Surgical approaches to the cavernous sinus:A microsurgical study (1990) Neurosurg, 6, pp. 903-932Kier, E.L., Embryology of the normal optic canal and its anomalies.An anatomic and roentgenographic stud (1966) Invest. Radiol, 1, pp. 346-362Kobayashi, S., Kyoshima, K., Gibo, H., Hedge, S.A., Takemae, T., Sugita, K., Carotid cave aneurysms of the internal carotid artery (1989) J. Neurosurg, 70, p. 216Lee, H.Y., Chung, I.H., Choi B., Y., Anterior, C., (1997) Yonsei Med. J, 38, pp. 151-154Narolewski, R., Significance of anatomic variants of bony surroundings of the internal carotid artery and their significance for lateral surgical approaches to the cavernous sinus (2003) Ann. Acad. Med. Stetin, 49, pp. 205-229Saka, E., Ozdoǧmus, O., Tulay, C., Gürdal, E., Uzün, I., The anatomy of the carotico-clinoid foramen and its relation with the internal carotid artery (2003) Surg. Radiol. Anat, 25, pp. 241-246Reisch, R., Vutskits, L., Filippi, R., Patonay, L., Fries, G., Perneczky, A., Topographic microsurgical anatomy of the paraclinoid carotid artery (2002) Neurosurg Rev, 25, pp. 177-183Sekhar, L.N., Akin, O., Anatomical study of the cavernous sinus emphasizing operative approaches and related vascular and neural reconstruction (1987) Neurosurg, 21, pp. 806-816Seoane, E., Rhoton, A.L., Oliveira, E., Microsurgical anatomy of the dural collar (carotid collar) and rings around the clinoid segment of the internal carotid artery (1998) Neurosurg, 42, pp. 869-886Sicher, H., du Brul, E.L., (1977) Oral Anatomy, , 6ed. Rio de Janeiro, Guanabara KooganStandring, S., Overview of the Development of the Head and Neck Head: Skull and Mandible Gray's anatomy: The anatomical basis of clinical practice, p. 2005. , New York, ElsevierEl foramen caróticoclinoideo es una estructura inconstante formada por la unión de la procesos clinoides anterior y medio. El objetivo de este estudio fue revisar la incidencia y la morfometría del foramen caróticoclinoideo en cráneos humanos brasileños y discutir sus implicaciones clínicas. Se utilizaron 80 cráneos humanos secos, de ambos sexos, determinando tres variables: sexo y lados derecho e izquierdo. La morfometría se realizó con un cáliper manual midiéndose el diámetro máximo del foramen. La incidencia de cráneos con al menos un foramen fue de 8,5%. El 8,5% de los cráneos presentó un foramen en el lado derecho y el 2,5% en el izquierdo. El 2,5% de los cráneos presentó un foramen bilateral y el 6,25% un foramen unilateral. En relación al sexo, los forámenes se encontraron en el 5% de los cráneos de hombres y el 12,5% de los cráneos de mujeres. El diámetro máximo de esta estructura presentó en promedio, valores de 5,23 mm; 5,18 mm en el lado derecho y 5,35 mm en el izquierdo; 5,30 mm en cráneos de hombres y 5.18 mm en cráneos de mujeres. Las características anatómicas de este foramen deben ser consideradas debido a las implicaciones clínicas asociadas a la neurocirugía, como la eliminación del proceso clinoides y a síntomas como cefaleas producto de alteraciones en la arteria carótida interna en esta región. En conclusión, el conocimiento de esta estructura mejora el diagnóstico y tratamiento de las complicaciones clínicas relacionadas con esta variació

    Changes In Soil Carbon, Nitrogen, And Phosphorus Due To Land-use Changes In Brazil

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    In this paper, soil carbon, nitrogen and phosphorus concentrations and stocks were investigated in agricultural and natural areas in 17 plot-level paired sites and in a regional survey encompassing more than 100 pasture soils In the paired sites, elemental soil concentrations and stocks were determined in native vegetation (forests and savannas), pastures and crop-livestock systems (CPSs). Nutrient stocks were calculated for the soil depth intervals 0-10, 0-30, and 0-60 cm for the paired sites and 0-10, and 0-30 cm for the pasture regional survey by sum stocks obtained in each sampling intervals (0-5, 5-10, 10-20, 20-30, 30-40, 40-60 cm). Overall, there were significant differences in soil element concentrations and ratios between different land uses, especially in the surface soil layers. Carbon and nitrogen contents were lower, while phosphorus contents were higher in the pasture and CPS soils than in native vegetation soils. Additionally, soil stoichiometry has changed with changes in land use. The soil C:N ratio was lower in the native vegetation than in the pasture and CPS soils, and the carbon and nitrogen to available phosphorus ratio (P-ME) decreased from the native vegetation to the pasture to the CPS soils. In the plot-level paired sites, the soil nitrogen stocks were lower in all depth intervals in pasture and in the CPS soils when compared with the native vegetation soils. On the other hand, the soil phosphorus stocks were higher in all depth intervals in agricultural soils when compared with the native vegetation soils. For the regional pasture survey, soil nitrogen and phosphorus stocks were lower in all soil intervals in pasture soils than in native vegetation soils. The nitrogen loss with cultivation observed here is in line with other studies and it seems to be a combination of decreasing organic matter inputs, in cases where crops replaced native forests, with an increase in soil organic matter decomposition that leads to a decrease in the long run. The main cause of the increase in soil phosphorus stocks in the CPS and pastures of the plot-level paired site seems to be linked to phosphorus fertilization by mineral and organics fertilizers. The findings of this paper illustrate that land-use changes that are currently common in Brazil alter soil concentrations, stocks and elemental ratios of carbon, nitrogen and phosphorus. These changes could have an impact on the subsequent vegetation, decreasing soil carbon and increasing nitrogen limitation but alleviating soil phosphorus deficiency.121547654780British Embass

    Position of the mandibular foramen in different facial shapes assessed by cone-beam computed tomography: a cross-sectional retrospective study

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    Purpose: The mandibular foramen, located on the internal surface of the mandibular ramus, is an important anatomical landmark for the success during the inferior alveolar nerve block. This cross-sectional retrospective study aimed to evaluate the location of the mandibular foramen through ConeBeam Computed Tomography (CBCT) in different facial shapes. Materials and Methods: The determination of the location of the mandibular foramen was performed using CBCT of mesocephalic, dolichocephalic and brachycephalic patients (n=40 each). The ramus width (W), the distance from the mandibular foramen to the deepest point of the anterior border of the mandibular ramus (D), the distance from the mandibular foramen to the lowest point of the mandibular notch (V) and the distance from the inferior border of the mandible to the lowest point in of the mandibular border (R), as well as the ratios W/D and V/R, were measured. ANCOVA, two-way ANOVA and Chi-square tests were used to analyze the variation among the facial shapes. Results.: The ramus width (W) was greater (p 0.0001) in the brachycephalic (28.4 +/- 0.5 mm) than in both mesocephalic (26.8 +/- 0.36 mm) and dolichocephalic (25.5 +/- 0.39 mm) patients. D (p=0.0433) and R (p=0.0072) were also greater in the brachycephalic (17.7 +/- 0.36 mm; 43.4 +/- 0.75 mm, respectively) than dolichocephalic (16.5 +/- 03 mm; 40.3 +/- 0.63 mm, respectively), but both did not differ from mesocephalic (17.34.36 mm; 41.8 +/- 0.66 mm, respectively) patients. The other measurements (V, W/J and R/V) did not significantly differ among facial shapes. Conclusion: The localization of the mandibular foramen was. in the horizontal direction, more posterior in the brachycephalic patients and, in the vertical direction, higher in the dolichocephalic patients, when compared to the other groups analyzed. Thus, the anatomic data found in this study may help dentists to increase the success of the inferior alveolar nerve block and prevent surgical complications.1354455

    Morfometría de la apertura piriforme y morfología de los huesos nasales en la población brasileña por la radiografía postero-anterior de Caldwell

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    CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOPiriform aperture and nasal bone contribute to the formation of the nose. Its morphology varies according to ethnic group and gender. The piriform apertures and nasal bones of 97 individuals were examined radiographically through Caldwell radiographic technique and the types of nasal bones were classified according to Hwang et al. (2005). The width, height and area of piriform aperture were measured to demonstrate the difference according to gender. Statistical analysis was performed from the Student t test and analysis of variance (ANOVA). The most frequent type of nasal bone was A, and D was the most uncommon in both genders. In the Student t test significant differences between genders, height, width and area of the piriform aperture were obtained and were larger in males when compared to females. The dimensions of the piriform aperture were higher in males when compared to females, and therefore may be used as parameter for the distinction of gender in Brazilian population. The type A of nasal bone was the most frequent in the Brazilian population, contributing to ethnic differentiation in human identification292393398CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informaçãoLa apertura piriforme y el hueso nasal contribuyen a la formación de la nariz. Su morfología varía de acuerdo a los grupos étnicos y al sexo. Este estudio evaluó la morfología de la apertura piriforme y el hueso nasal y su relación con el sexo. Las aperturas piriformes y los huesos nasales de 97 personas fueron examinados radiográficamente mediante la técnica radiográfica de Caldwell, y los tipos de huesos nasales se clasificaron de acuerdo con Hwang et al. (2005). Se midió el ancho, la altura y el área de la apertura piriforme para demostrar las diferencias por sexo. El análisis estadístico se realizó a partir de la prueba t de Student y análisis de varianza (ANOVA). El tipo más frecuente de hueso nasal fue la A, y la D fue la menos común, en ambos sexos. En la prueba t de Student se obtuvo diferencias significativas entre los sexos, altura, ancho y área de la apertura piriforme, las que fueron mayores en hombres en comparación a las mujeres. Las dimensiones de la apertura piriforme fueron mayores en los hombres que en las mujeres, por lo que se puede utilizar como parámetro para la distinción de sexo en la población brasileña. En la población brasileña el tipo A de hueso nasal fue el más frecuente, lo que contribuye para la diferenciación étnica en la identificación human

    Relaciones entre el canal mandibular y clases I, II y III de Angle en radiografías panorámicas

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOTo prevent injury to the inferior alveolar nerve during dental procedures, knowledge of its anatomical location and course of the mandibular canal is imperative. The aim of this study was evaluate the location on panoramic radiographs of the mandibular canal in relation to the apices of the permanent mandibular molars and base mandible, and relate the type of mandibular canal with Angle classes I, II and III. We evaluated 748 panoramic radiographs distributed according to sex and occlusal class (Angle I, II and III) of fully dentate individuals, 18-51 age group. The radiographs were divided according to Angle classes based on cephalometric tracing, clinical data from the medical records of each individual and the analysis of of the maxillar and mandibular dental arches models. The same individuals had the mandibular canal bilaterally assessed, and classified according to their location relative to the root apices of the mandibular molars and mandible base. Measurements of the distance from the mandibular canal to the apices of the teeth and mandible base were made on the Software ImageLab2000®. The intra-observer reproducibility of measurements on radiographs was assessed using the coefficient of variation (p<0.0001). Data were submitted to Kruskal-Wallis test, on software BioEstat 5.0. There were statistically significant differences (Kruskal-Wallis test, p <0.0001) between the occlusal classes, with the type of mandibular canal. A larger number of canals types 2 and 3 in class III individuals than in others. In conclusion, the location of the mandibular canal presents morphological changes in relation to the apices of the permanent molars, and the mandibular base according to the Angle classes I, II and III.To prevent injury to the inferior alveolar nerve during dental procedures, knowledge of its anatomical location and course of the mandibular canal is imperative. The aim of this study was evaluate the location on panoramic radiographs of the mandibular canal in relation to the apices of the permanent mandibular molars and base mandible, and relate the type of mandibular canal with Angle classes I, II and III. We evaluated 748 panoramic radiographs distributed according to sex and occlusal class (Angle I, II and III) of fully dentate individuals, 18-51 age group. The radiographs were divided according to Angle classes based on cephalometric tracing, clinical data from the medical records of each individual and the analysis of of the maxillar and mandibular dental arches models. The same individuals had the mandibular canal bilaterally assessed, and classified according to their location relative to the root apices of the mandibular molars and mandible base. Measurements of the distance from the mandibular canal to the apices of the teeth and mandible base were made on the Software ImageLab2000®. The intra-observer reproducibility of measurements on radiographs was assessed using the coefficient of variation (p<0.0001). Data were submitted to Kruskal-Wallis test, on software BioEstat 5.0. There were statistically significant differences (Kruskal-Wallis test, p <0.0001) between the occlusal classes, with the type of mandibular canal. A larger number of canals types 2 and 3 in class III individuals than in others. In conclusion, the location of the mandibular canal presents morphological changes in relation to the apices of the permanent molars, and the mandibular base according to the Angle classes I, II and III322449454FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOsem informaçãoPara evitar lesiones del nervio alveolar inferior durante los procedimientos odontológicos, el conocimiento de la localización anatómica y curso del canal mandibular (CM) es imprescindible. El objetivo fue evaluar la localización del CM sobre radiografías panorámicas en relación con los ápices de los molares mandibulares permanentes y la base mandibular, relacionando el tipo de CM con las clases I, II y III de Angle. Se evaluaron 748 radiografías panorámicas distribuidas según sexo y clase oclusal (I, II y III de Angle) en individuos totalmente dentados (edad entre 18-51 años). Las radiografías fueron divididas de acuerdo a las clases de Angle según su trazado cefalométrico, datos clínicos de los registros médicos de cada individuo y el análisis de modelos de sus arcos dentarios mandibulares y maxilares. En los individuos se evaluó el CM bilateralmente y se clasificó de acuerdo a su ubicación en relación con los ápices radiculares de los molares mandibulares y base mandibular. Las mediciones de distancia desde el CM a los ápices radiculares y base mandibular se hicieron con el programa ImageLab2000®. Se evaluó la reproducibilidad intra-observador de las mediciones en las radiografías usando el coeficiente de variación (p<0,0001). Los datos fueron sometidos a la prueba de Kruskal ­Wallis con el programa BioEstat 5.0. Se observaron diferencias estadísticamente significativas (prueba de Kruskal-Wallis, p<0,0001) entre las clases oclusales y el tipo de CM. Hubo mayor número de canales tipos 2 y 3 en los individuos clase III. La ubicación del canal mandibular presenta cambios morfológicos en relación con los ápices de molares permanentes y la base mandibular de acuerdo a las clases I, II y III de Angl

    Methylparaben concentration in commercial Brazilian local anesthetics solutions

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOTo detect the presence and concentration of methylparaben in cartridges of commercial Brazilian local anesthetics. Twelve commercial brands (4 in glass and 8 in plastic cartridges) of local anesthetic solutions for use in dentistry were purchased from the Brazilian market and analyzed. Different lots of the commercial brands were obtained in different Brazilian cities (Piracicaba, Campinas and Sao Paulo). Separation was performed using high performance liquid chromatography (HPLC) with UV-Vis detector. The mobile phase used was acetonitrile: water (75:25 - v/v), pH 4.5, adjusted with acetic acid at a flow rate of 1.0 ml.min(-1). When detected in the solutions, the methylparaben concentration ranged from 0.01% (m/v) to 0.16% (m/v). One glass and all plastic cartridges presented methylparaben. 1. Methylparaben concentration varied among solutions from different manufacturers, and it was not indicated in the drug package inserts; 2. Since the presence of methylparaben in dental anesthetics is not regulated by the Brazilian National Health Surveillance Agency (ANVISA) and this substance could cause allergic reactions, it is important to alert dentists about its possible presence204444448FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOsem informaçã

    European Archaeological Research Projects. Un database sulle opportunità di scavo

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    Si illustrano le motivazioni e gli obbiettivi che hanno spinto alla creazione di un servizio di opportunità di scavo in rete per gli studenti in archeologia europe
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