Morphological study of Sr2CeO4 blue phosphor with fine particles

Morphological and spectroscopic studies of Sr2CeO4 blue phosphor in the form of fine particles prepared from a powdered multi-component precursor, via a combustion method, are reported. Samples were also prepared through a solid-state reaction and from a polymeric precursor for comparison. Citric acid or glycine as fuels in the combustion method lead to a mixture which is heated at 950 ºC for 4 h, resulting in spheroidal particles with a diameter between 250-550 nm. Samples from the polymeric precursor result in spheroidal particles (350-550 nm) and from the solid-state reaction in irregular particles (~ 5 mum). Therefore, the combustion method is adequate for preparation of Sr2CeO4 in the form of spherical fine particles.

Flotação da mistura argila-quartzo com surfactantes e estudos de pilarização

Clay is often employed as a catalyst, but quartz impurities can decrease the catalytic efficiency. Fine particles of clay can be purified by flotation. We examined the cationic surfactant hexadecyltrimethylammonium bromide (HTAB), the anionic sodium dodecyl sulfate (SDS) and the non-ionic TRITON X-100 for separating the quartz impurities from clay. Using X-ray diffraction, the separation was monitored for changes in the peaks corresponding to clay and quartz. Cationic surfactant HTAB was most effective in separating the quartz-clay mixture and the selectivity can be explained by internal adsorption of the surfactant onto the clay and external adsorption onto the quartz.

Elementos traço em material particulado atmosférico de uma região agroindustrial do sudeste do Brasil

Trace element concentrations were measured in atmospheric particulate matter collected in 2009 and 2010, in a Brazilian region influenced by pre-harvest burning of sugar cane crops. For coarse particles, high concentrations of Al, Fe, K and Ca suggested that re-suspended soil dust was the main source of aerosol trace elements, subsequently confirmed by XRD analysis. High levels of K, Zn, As, Cd and Pb were found in fine particles, confirming the contribution of biomass burning and vehicle emissions, whereas Na, Al, K, Fe and Zn were the representative elements in ultrafine particles, influenced by a diversity of sources.

Rotavírus, adenovírus, astrovírus, calicivírus e "Small Round Virus Particles" em fezes de crianças, com e sem diarréia aguda, no período de 1987 a 1988, na Grande São Paulo

No período de agosto de 1987 a setembro de 1988, 193 amostras de fezes de crianças, com e sem sintomatologia diarréica aguda, foram submetidas às provas diagnósticas do ensaio imunoenzimático (EIE), eletroforese em gel de poliacrilamida (EGPA) e microscopia eletrônica (ME) para a detecção de vírus. A positividade para Rotavírus, Adenovírus, Astrovírus, Calicivírus e "Small Round Virus Particles" (SRVP) foi encontrada nas 97 crianças com diarréia aguda em 11,3%, 3,1%, 2,1%, l,0%e4,l%, respectivamente. Das 96 crianças sem diarréia, 4,2% foram positivas para Rotavírus, 1,0% para Calicivírus e 7,3% para SRVP. Das 15 amostras positivas para Rotavírus, 14 apresentaram perfil eletroforético característico do Grupo A e 1 amostra do Grupo C. A análise dos eletroforotipos demonstrou a grande heterogeneidade de perfis e a predominância do perfil "longo". A associação de vírus, bactéria e parasita foi encontrada tanto em crianças com diarréia como em crianças sem diarréia.

Immunoperoxidase for the detection for the detection of antibodies in cerebrospinal fluid in neurocysticercosis: use of Cysticercus cellulosae and Cysticercus longicollis particles fixed on microscopy slides

The ORF strain of Cysticercus longicollis represents an important model for the study of heterologous antigens in the immunodiagnosis of neurocysticercosis (NC). The immunoperoxidase (IP) technique was standardized using a particulate antigen suspension of Cysticercus longicollis (Cl) and Cysticercus cellulosae (Cc). Cerebrospinal fluid (CSF) samples were incubated on the antigen fixed to microscopy slides; the conjugate employed was anti-IgG-peroxidase and the enzymatic reaction was started by covering the slides with chromogen solution (diaminobenzidine/H2O2). After washing with distilled water, the slide was stained with 2% malachite green in water. Of the CSF samples from 21 patients with NC, 19 (90.5%) were positive, whereas the 8 CSF samples from the control group (100%) were negative. The results of the IP-Cl test applied to 127 CSF samples from patients with suspected NC showed 28.3% reactivity as opposed to 29.1 % for the IP-Cc test. The agreement index for the IP test (Cl x Cc) was 94.2%, with no significant difference between the two antigens.

Flow cytometric quantitation of phagocytosis in heparinized complete blood with latex particles and Candida albicans

We report a rapid method for the flow cytometric quantitation of phagocytosis in heparinized complete peripherial blood (HCPB), using commercially available phycoerythrin-conjugated latex particles of 1µm diameter. The method is faster and shows greater reproducibility than Bjerknes' (1984) standard technique using propidium iodide-stained Candida albicans, conventionally applied to the leukocytic layer of peripherial blood but here modified for HCPB. We also report a modification of Bjerknes' Intracellular Killing Test to allow its application to HCPB.

Computed tomography-guided biopsy of mediastinal lesions: fine versus cutting needles

PURPOSE: To report the experience of a radiology department in the use of computed tomography guided biopsies of mediastinal lesions with fine and cutting needles, describing the differences between them. The results of adequacy of the sample and histologic diagnoses are presented according to the type of needle used. METHODS: We present a retrospective study of mediastinal biopsies guided by computed tomography performed from January 1993 to December 1999. Eighty-six patients underwent mediastinal biopsy in this period, 37 with cutting needles, 38 with fine needles, and 11 with both types (total of 97 biopsies). RESULTS: In most cases, it was possible to obtain an adequate sample (82.5%) and specific diagnosis (67.0%). Cutting-needle biopsy produced a higher percentage of adequate samples (89.6% versus 75.5%, P = 0.068) and of specific diagnosis (81.3% versus 53.1%, P = 0.003) than fine-needle biopsy. There were no complications that required intervention in either group. CONCLUSION: Because they are practical, safe, and can provide accurate diagnoses, image-guided biopsies should be considered the procedure of choice in the initial exploration of patients with mediastinal masses. In our experience, cutting needles gave higher quality samples and diagnostic rates. We recommend the use of cutting needles as the preferred procedure.

Essential oil composition of leaf and fine stem of Aniba canelilla (Kunth) Mez from Manaus, Brazil

The essential oil of the leaves and fine stems of Aniba canelilla (Kunth) Mez collected in the city of Manaus, AM, Brazil, were obtained by hydrodistillation and analyzed by GC/MS. Forty-two components were identified, of which 1-nitro-2-phenylethane, as expected, was the major (71.2%-68.2%).

Fine litter accumulation in Central Amazonian Tropical Rainforest canopy

Fine litter dynamics within the canopy differ from litter dynamics on the forest floor for reasons such as differences in microclimate, substrate, disturbance level, stratum influence and decomposition rates. This study is the first attempt to quantify the fine litter accumulated in the canopy of Central Amazonian forests. We compared the canopy litter accumulation to fine litter-layer on forest floor and to other forests and also investigated which were the mostly accumulated litter omponents. We found that Central Amazonian Rainforest intercepts greater fine litter in the canopy (294 g.m-2) compared to other forest formations with higher winds speed as in a Costa Rican Cloud Forest (170 g.m-2). The mean canopy fine litter accumulated at the end of the dry season was less than a half of that on soil surface (833 g.m-2) and the fine wood component dominates the canopy samplings (174 g.m-2) while leafy component predominate on soil surface litter (353 g.m-2).

Fine-root production in two secondary forest sites with distinct ages in Eastern Amazon

The objective of this work was to assess the fine-root (≤ 2 mm diameter) production dynamics of two forest regrowths at different ages. Fine-root production was monitored by the ingrowth core method in one 18-year-old site (2 ha) and one 10-year-old site (0.5 ha), both localized in the Apeú region, Northern Pará State, Brazil. The sites were abandoned after successive shifting cultivation, beginning in 1940. Monthly production of live fine-root was similar between sites and was influenced by rainfall seasonality, with higher production during the dry season than the wet season for mass and length. However, mortality in terms of mass was higher in the 10-year-old site than in the 18-year-old site. The seasonality influenced mortality only in the 18-year old site following the pattern observed for live fine-root. The influence seasonal on mortality in terms of length was different between sites, with higher mortality during the wet season in the 10-year-old site and higher mortality during the dry season in the 18-year-old site. Specific root length was higher during the wet season and at the 10-year-old site. Fine-root production was not influenced by the chronosequence of the sites studied, probably fine-root production may have already stabilized in the sites or it depended more on climate and soil conditions. The production of fine-roots mass and length were indicators that generally showed the same pattern.

Biomass production and essential oil yield from leaves, fine stems and resprouts using pruning the crown of Aniba canelilla (H.B.K.) (Lauraceae) in the Central Amazon

Aniba canelilla (H.B.K.) Mez. is a tree species from Amazon that produces essential oil. The oil extraction from its leaves and stems can be an alternative way to avoid the tree cutting for production of essential oil. The aim of this study was to analyse factors that may influence the essential oil production and the biomass of resprouts after pruning the leaves and stems of A. canelilla trees. The tree crowns were pruned in the wet season and after nine months the leaves and stems of the remaining crown and the resprouts were collected, in the dry season. The results showed that the essential oil yield and chemical composition differed among the stems, leaves and resprouts. The stems' essential oil production differed between the seasons and had a higher production in the resprouting stems than the old stems of the remaining crown. The production of essential oil and leaf biomass of resprouts were differently related to the canopy openness, indicating that light increases the production of the essential oil and decreases the biomass of resprouting leaves. This study revealed that plant organs differ in their essential oil production and that the canopy openness must be taken into account when pruning the A. canelilla tree crown in order to achieve higher oil productivity.

Sôbre a hiperplasia celular no mixoma infectuoso do coelho

Definite hyperplasia of cells occurs in the skin lesions of the infectious myxoma of rabbits, more visible in such stages in which the intercellular basophilic substance is rather scanty (fig. 2). The increase in number of cells is the result of simplified forms of mitosis (modified type of mitosis, pseudoamitosis) which might readily be mistaken for amitosis in their final stages. Budding (figs. 20, 28, 29, 30) as well as constriction of the nucleus (figs. 18, 31, 32), and the formation of giant-cells (figs. 33, 34) are not rare. During the entire process the nuclear membrane does not desintegrate as in typical mitosis. Division of the cytoplasm following division of the nucleus has been demonstrated (fig. 17). Typical mitosis is practically absent. The cells which undergo hyperplasia present remarkable changes in their dimension, shape, and structure. The nucleus and cell-body are considerably enlarged (figs. 6, 7, 8). The shape of the nucleus is modified (figs. 8, 10, 15). Hypertrophy of nuclein, either as an intranuclear network (spireme?, figs. 9, 23), or in the form conspicuous, deeply staining masses which appear not to be homogeneous but to be composed of small particles closely clumped ("mulberries"?, figs. 12, 13, 14, 25, 26) occurs in most cells. While some of these pictures are probably related to necrosis of the cells as started by most of the previous workers, it is lekely that some of them may represent developmental stages of the modified mitosis (pseudoamitosis) here reported. In fact, fine cytological details not ordinarily preserved in necrotic cells (figs. 35, 36, 37) may be demonstrated in the socalled myxoma-cells subtted to approved cytological methods of study (fixation in B-15 and P. F. A.-3, staining in iron-hematoxylin).

The fine structure of the endogenous stages of Isospora hemidactyli carini, 1936 in the gecko Hemidactylus mabouia from North Brazil

The ultrastructure is described of the meronts, microgamonts and young oocyst stages of Isospora hemidactyli of the gecko Hemidactylus mabouia from Belém, PA, north Brazil. The endogenous stages all develop in the nucleus of the gut epithelial cells. The nucleus remains intact up to the latest stages of the parasite's development, but degenerates by the time the oocyst appears. Merogonic division appears to be asynchronous, and some of the differentiated merozoites contained more than one nucleus. Microgamonts conform in structure with those of other eimeriids. Some of the type 2 wall-forming bodies disintegrate into smaller globules and ground substance of lower density.

Fine structure of Henneguya hemiodopsis sp. n. (Myxozoa), a parasite of the gills of the Brazilian teleostean fish Hemiodopsis microlepes (Hemiodontidae)

A fish-infecting myxosporean, Henneguya hemiodopsis sp. n., found infecting the gills of Hemiodopsis microlepis and collected from the Poty River near the city of Teresina, Brazil, was described based on ultrastructural studies. The parasite occurred within large whitish polysporic plasmodia (up to 200 μm in diameter) containing asynchronous developmental sporogonic stages, mainly mature spores. The spores measured 19.7 ± 0.9 μm in total length (n = 30) and the ellipsoidal spore body was 10.8 ± 0.5 μm long, 3.3 ± 0.4 μm wide and 2.5 ± 0.5 μm thick. The spores were composed of two equal shell valves adhering together along the straight suture line, with each valve having equal-sized caudal tapering tails measuring 8.7 ± 0.6 μm in length. The spores were surrounded by a thin anastomosed network of microfibrils, more evident on the tails. There were two symmetric elongated bottle-like polar capsules 3.5 ± 0.3 μm long and 1.0 ± 0.2 μm wide, each with a polar filament with five to six coils. Given the morphological and ultrastructural differences from previously described parasites and the specificity of the host species, we propose a new species, named H. hemiodopsis sp. n.