Scientific societal meetings as opportunities for science eduation in developing countries

Brazilian Scientific productivity presented a remarkable growth during the last two decades, as inferred by the number of articles published by Brazilian authors. The number of Brazilian secondary students also grew sharply. Together, those factors lead to a scenario in which there is an increase science produced locally, a great demand for information but a paucity of resources to make it available for the youth. We have evaluated by using quantitative and qualitative approaches the potential of societal meetings as opportunities for science education. Students acquire scientific knowledge and also autonomously develop consistent strategies for choosing and attending activities to maximize their learning. Those results suggest that scientific meetings may represent an underestimated potential for science education in developing countries

Microwave-Driven Hexagonal-to-Monoclinic Transition in BiPO4: An In-Depth Experimental Investigation and First-Principles Study

Present theoretical and experimental work provides an in-depth understanding of the morphological, structural, electronic, and optical properties of hexagonal and monoclinic polymorphs of bismuth phosphate (BiPO4). Herein, we demonstrate how microwave irradiation induces the transformation of a hexagonal phase to a monoclinic phase in a short period of time and, thus, the photocatalytic performance of BiPO4. To complement and rationalize the experimental results, first-principles calculations have been performed within the framework of density functional theory. This was aimed at obtaining the geometric, energetic, and structural parameters as well as vibrational frequencies; further, the electronic properties (band structure diagram and density of states) of the bulk and corresponding surfaces of both the hexagonal and monoclinic phases of BiPO4 were also acquired. A detailed characterization of the low vibrational modes of both the hexagonal and monoclinic polymorphs is key to explaining the irreversible phase transformation from hexagonal to monoclinic. On the basis of the calculated values of the surface energies, a map of the available morphologies of both phases was obtained by using Wulff construction and compared to the observed scanning electron microscopy images. The BiPO4 crystals obtained after 16–32 min of microwave irradiation provided excellent photodegradation of Rhodamine B under visible-light irradiation. This enhancement was found to be related to the surface energy and the types of clusters formed on the exposed surfaces of the morphology. These findings provide details of the hexagonal-to-monoclinic phase transition in BiPO4 during microwave irradiation; further, the results will assist in the design of electronic devices with higher efficiency and reliability

Synthesis, Characterization and Photophysical Properties of Eu 3+ Doped in BaMoO 4

and 4 Eu 3+ transitions at 523, 533, 554, 578, 589, 614, 652 and 699 nm, respectively. The emission spectra of the powders heat-treated at 800 and 900°C showed a marked increase in its intensities compared to the materials heattreated from 400 to 700°C. The decay times for the sample were evaluated and all of them presented the average value of 0.61 ms. Eu 3+ luminescence decay time follows one exponential curve indicating the presence of only one type of Eu 3+ symmetry site

Effect of different solvent ratios (water/ethylene glycol) on the growth process of CaMo'O IND.4' crystals and their optical properties

ABSTRACT: In this paper, calcium molybdate (CaMoO4) crystals (meso- and nanoscale) were synthesized by the coprecipitation\ud method using different solvent volume ratios (water/ethylene glycol). Subsequently, the obtained suspensions were\ud processed in microwave-assisted hydrothermal/solvothermal systems at 140 C for 1 h. These meso- and nanocrystals processed\ud were characterized by X-ray diffraction (XRD), Fourier transform Raman (FT-Raman), Fourier transform infrared (FT-IR),\ud ultraviolet-visible (UV-vis) absorption spectroscopies, field-emission gun scanning electron microscopy (FEG-SEM),\ud transmission electron microscopy (TEM), and photoluminescence (PL) measurements. XRD patterns and FT-Raman spectra\ud showed that these meso- and nanocrystals have a scheelite-type tetragonal structure without the presence of deleterious phases.\ud FT-IR spectra exhibited a large absorption band situated at around 827 cm-1, which is associated with the Mo-O antisymmetric\ud stretching vibrations into the [MoO4] clusters. FEG-SEM micrographs indicated that the ethylene glycol concentration\ud in the aqueous solution plays an important role in the morphological evolution of CaMoO4 crystals. High-resolution\ud TEM micrographs demonstrated that the mesocrystals consist of several aggregated nanoparticles with electron diffraction\ud patterns of monocrystal. In addition, the differences observed in the selected area electron diffraction patterns of CaMoO4\ud crystals proved the coexistence of both nano- and mesostructures. First-principles quantum mechanical calculations based on\ud the density functional theory at the B3LYP level were employed in order to understand the band structure and density of states\ud for the CaMoO4. UV-vis absorption measurements evidenced a variation in optical band gap values (from 3.42 to 3.72 eV) for\ud the distinct morphologies. The blue and green PL emissions observed in these crystals were ascribed to the intermediary energy\ud levels arising from the distortions on the [MoO4] clusters due to intrinsic defects in the lattice of anisotropic/isotropic crystals.FAPESP (09/50303-4)CNPqCAPE

Effects of bromopride on the healing of left colon anastomoses of rats

Objetivo: Avaliar os efeitos da bromoprida sobre a formação de aderências e a cicatrização de anastomoses de cólon esquerdo de ratos. Métodos: Foram incluídos 40 ratos, divididos em dois grupos contendo 20 animais, para administração de bromoprida (grupo de estudo- E) ou solução fisiológica (grupo controle- C). Cada grupo foi dividido em subgrupos contendo 10 animais cada, para eutanásia no terceiro (E3 e C3) ou no sétimo dia (E7 e C7) de pós-operatório. Os ratos foram submetidos à secção do cólon esquerdo e anastomose término-terminal. No dia da relaparotomia, foi avaliada a quantidade total de aderências e removido um segmento colônico contendo a anastomose para análise histopatológica, da força de ruptura e da concentração de hidroxiprolina. Resultados: Não houve diferença entre os grupos em relação à evolução clínica. Dois animais do grupo de estudo apresentaram deiscência de anastomose bloqueada. Os animais que receberam bromoprida apresentaram número de aderências intracavitárias e aderências à anastomose semelhantes ao grupo controle. As anastomoses dos animais do grupo E3 apresentaram menor resistência de ruptura do que as do grupo C3 (p=0,04). Este efeito não ocorreu no sétimo dia de pós-operatório (p=0,37). Não houve diferença significativa entre os grupos em relação à histopatologia ou concentração de hidroxiprolina das anastomoses. Conclusão: O uso da bromoprida está associado à diminuição da resistência tênsil de anastomoses do cólon esquerdo de ratos no terceiro dia de pós-operatório.Objective: To evaluate the effects of bromopride on the formation of adhesions and anastomotic healing in the left colon of rats. Methods: We divided 40 rats into two groups of 20 animals, administration of bromopride (study group-E) or saline (control group- C). Each group was divided into subgroups containing 10 animals each for euthanasia in the third (C3 and E3) or the seventh (E7 and C7) postoperative days. The rats were submitted to section of the left colon and end-to-end anastomosis. On the day of reoperation, we evaluated the total amount of adhesions and removed a colonic segment containing the anastomosis for histopathological analysis, assessment of rupture strength and hydroxyproline concentration. Results: There was no difference between groups in relation to clinical outcome. Two animals in the study group had blocked anastomotic leakage. The animals that received bromopride had the number of intracavitary adhesions and adhesions to the anastomosis similar to the control group. The anastomoses from the group E3 animals showed lower resistance to rupture the one from the C3 group (p = 0.04). This effect did not occur on the seventh postoperative day (p = 0.37). There was no significant difference between groups in relation to histopathology and hydroxyproline concentration in the anastomoses. Conclusion: The use of bromopride was associated with decreased tensile strength of left colon anastomosis in rats in the third postoperative day

Synthesis of (Ca,Nd)Ti'O IND.3' powders by complex polymerization, Rietveld refinement and optical properties

Neodymium calcium titanate, (Ca0.99Nd0.01)TiO3 powders were synthesized by the complex polymerization method and heat treated at different temperatures for 2 h under air atmosphere. The structural evolution of these powders as a function of heat treatment temperature was analyzed by X-ray diffraction (XRD) and micro-Raman (MR) spectroscopy. The optical properties were investigated by Ultraviolet–visible (UV–vis) absorption spectroscopy and Photoluminescence (PL) measurements. XRD patterns, Rietveld refinement and MR spectra indicated that the powders heated treated at 750 °°C for 2 h present an orthorhombic structure without secondary phases. UV–vis measurements suggested the presence of intermediary energy in disordered (Ca0.99Nd0.01)TiO3 powders. Broad and narrow bands were observed in the PL spectra of these powders when excited with 350 nm wavelength. The broad bands were associated to the structural defects and/or p–d electronic transitions while, the narrow bands were ascribed to f–f transitions arising from Nd3+ ions.CAPESCNPQFAPES

Gamma/hadron discrimination using a small-WCD with four PMTs

The Southern Wide-field Gamma-ray Observatory (SWGO) is the next-generation gamma-ray observatory, currently in an R&D phase. The experiment is expected to have a large array of water Cherenkov detectors (WCD) placed at a high elevation (> 4.4 km a.s.l.) in South America. Here we present a WCD concept with reduced surface area and height of stations comprising four PMTs at the bottom. We show that it is possible to reach an excellent gamma/hadron discrimination by analysing the data gathered by this station with machine learning techniques. Such performance can be achieved by analysing the shower patterns at the ground or through the PMTs signal time structure to tag muons. Moreover, it is shown that the station's performance does not depend on the array configuration (dense or sparse) nor on the shower inclination (θ< 40◦). Such a concept reduces the cost associated with the transport of massive amounts of water to high elevation sites while keeping a high physics performance. Therefore, it could be a good candidate station for SWGO, enabling to reach good sensitivities from low energies (∼ 100 GeV) up to the PeV region, covering large ground surface areas (few square km)

SLC35A2â CDG: Functional characterization, expanded molecular, clinical, and biochemical phenotypes of 30 unreported Individuals

Pathogenic de novo variants in the Xâ linked gene SLC35A2 encoding the major Golgiâ localized UDPâ galactose transporter required for proper protein and lipid glycosylation cause a rare type of congenital disorder of glycosylation known as SLC35A2â congenital disorders of glycosylation (CDG; formerly CDGâ IIm). To date, 29 unique de novo variants from 32 unrelated individuals have been described in the literature. The majority of affected individuals are primarily characterized by varying degrees of neurological impairments with or without skeletal abnormalities. Surprisingly, most affected individuals do not show abnormalities in serum transferrin Nâ glycosylation, a common biomarker for most types of CDG. Here we present data characterizing 30 individuals and add 26 new variants, the single largest study involving SLC35A2â CDG. The great majority of these individuals had normal transferrin glycosylation. In addition, expanding the molecular and clinical spectrum of this rare disorder, we developed a robust and reliable biochemical assay to assess SLC35A2â dependent UDPâ galactose transport activity in primary fibroblasts. Finally, we show that transport activity is directly correlated to the ratio of wildâ type to mutant alleles in fibroblasts from affected individuals.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150498/1/humu23731_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150498/2/humu23731-sup-0001-Supp_Mat__2019.2.10_.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150498/3/humu23731.pd