917 resultados para stage 4 and 5


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The layered chalcogenides, having structures analogous to graphite, are known to be unstable toward bending and show high propensity to form curved structures, thus eliminating dangling bonds at the edges. Since the discovery of fullerene and nanotube structures of WS2 and MoS2 by Tenne et al. [1-3], there have been attempts to prepare and characterize nanotubes of other layered dichalcogenides with structures analogous to MoS2. Nanotubes of MoS2 and WS2 were prepared by Tenne et al. by reducing the corresponding oxides to the suboxides followed by heating in an atmosphere of forming gas (5 % H-2 + 95 % N-2) and H2S at 700-900 degreesC [1-3]. Alternative methods of synthesis of MoS2 and WS2 nanotubes have since been proposed by employing the decomposition of the ammonium thiometallates or the corresponding trisulfide precursors. This alternative procedure was based on the observation that the trisulfide seems to be formed as an intermediate in the synthesis of the MoS2 and WS2 nanotubes [4]. Accordingly, the decomposition of the trisulfides of MoS2 and W in a reducing atmosphere directly yielded nanotubes of the disulfides MoS2 and WS2 [5]. In this article, we describe the synthesis, structure, and characterization of a few novel nanotubes of the disulfides of groups 4 and 5 metals. These include nanotubes of NbS2, TaS2, ZrS2, and HfS2. The study enlarges the scope of the inorganic nanotubes significantly and promises other interesting possibilities, including the synthesis of the diselenide nanotubes of these metals.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Survey map of the Second Welland Canal created by the Welland Canal Company showing the Town of St. Catharines. Identified structures associated with the Canal include Lock 4, Lock House, Lock 5, Small Lock House, the towing path, and Gasometer for Canal. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include streets and roads (ex. Geneva Street, Queenston Street, and Academy Street), C. Phelps Mill and Store House, St. Catharines and Welland Canal Gas Works, William Mahony's Tannery, Cooper Shop, a barrel shed, barn, and gas tanks. Properties and property owners of note are: Concession 6 Lots 14, 14, and 16, Concession 7 Lots 14, 15, and 16, C. Phelps, R. M. Clement, Orson Phelps, R. Collier, D. P. Haynes, W. Chace, and John Soper.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We analyzed Brazil`s efforts in reducing child mortality, improving maternal and child health, and reducing socioeconomic and regional inequalities from 1990 through 2007. We compiled and reanalyzed data from several sources, including vital statistics and population-based surveys. We also explored the roles of broad socioeconomic and demographic changes and the introduction of health sector and other reform measures in explaining the improvements observed. Our findings provide compelling evidence that pro-active measures to reduce health disparities accompanied by socioeconomic progress can result in measurable improvements in the health of children and mothers in a relatively short interval. Our analysis of Brazil`s successes and remaining challenges to reach and surpass Millennium Development Goals 4 and 5 can provide important lessons for other low- and middle-income countries. (Am J Public Health. 2010;100:1877-1889. doi:10.2105/AJPH.2010.196816)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Rank-order and paired comparison tests are widely used methods to assess previous termsensorynext term perception of young children. Small age differences could, however, influence the ability of children to carry out such tasks. This study compared rank-order and paired comparison tests for previous termconsistencynext term in previous term4next term- and 5-year-old children. During previous termfournext term sessions, 22 young adults, 21 previous term4next term-year-old and 47 5-year-old children carried out rank-order and paired comparison tests to measure discriminatory ability (0.22 M, 0.25 M, 0.29 M, 0.34 M, 0.39 M sucrose in orangeade) and preference (0.14 M, 0.20 M, 0.29 M, 0.42 M, 0.61 M sucrose in orangeade). Young adults and 5-year-old children were able to discriminate between all solutions and showed a high previous termconsistencynext term between the rank-order and pair-wise tests for discriminatory ability (>76% previous termconsistency)next term and preference (>71% previous termconsistency)next term. In contrast, previous term4next term-year-olds detected differences in sweetness during the preference tests, but failed to distinguish sweetness intensities during the discriminatory ability tests. It is concluded that the dissimilarity between previous term4next term-and 5-year-olds in performing previous termsensorynext term tests was due to a difference in their cognitive skills rather than their previous termsensorynext term perceptual differences.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We investigated the relationships in children between rules that restrict consumption of mono- and disaccharides (MDS), consumption of MDS and preferences for sucrose-containing orangeade. The background ideas of restriction rules we also investigated. To this end, 44 children (5.1 ^ 0.5 years) performed a rank-order and paired-comparison test of preference for five orangeades, which differed in sucrose concentration (0.14, 0.20, 0.29, 0.42, 0.61 M sucrose). Parents filled out a questionnaire concerning restriction rules and their children’s consumption of MDS-containing foods. Stronger restriction rules were related to a lower consumption of beverages that contained MDS and to a lower consumption of MDS-containing foods during breakfast and lunch. The most freedom to choose foods that contain MDS was given during the afternoon. Fifty-five percent of the children who were highly restricted showed a preference for the highest concentration of sucrose in orangeade. None of these children preferred the orangeade with the lowest concentration of sucrose. While 19% of the children who were little restricted preferred the beverage with the lowest concentration of sucrose, 33% preferred the beverage with the highest concentration. These parents generally believed that sugar has a bad effect on health and had similar background ideas concerning restriction
rules.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This research provides insight into the evolution and function of zebrafish cell signaling proteins, Suppressor of Cytokine Signaling 4a, 4b and 5a. These signaling proteins were found to play essential roles during early and late stages of embryonic development, with specific roles in sensory processing and immune cell development.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (Apo2L/TRAIL) belongs to the TNF family known to transduce their death signals via cell membrane receptors. Because it has been shown that Apo2L/TRAIL induces apoptosis in tumor cells without or little toxicity to normal cells, this cytokine became of special interest for cancer research. Unfortunately, cancer cells are often resistant to Apo2L/TRAIL-induced apoptosis; however, this can be at least partially negotiated by parallel treatment with other substances, such as chemotherapeutic agents. Here, we report that cardiac glycosides, which have been used for the treatment of cardiac failure for many years, sensitize lung cancer cells but not normal human peripheral blood mononuclear cells to Apo2L/TRAIL-induced apoptosis. Sensitization to Apo2L/TRAIL mediated by cardiac glycosides was accompanied by up-regulation of death receptors 4 (DR4) and 5 (DR5) on both RNA and protein levels. The use of small interfering RNA revealed that up-regulation of death receptors is essential for the demonstrated augmentation of apoptosis. Blocking of up-regulation of DR4 and DR5 alone significantly reduced cell death after combined treatment with cardiac glycosides and Apo2L/TRAIL. Combined silencing of DR4 and DR5 abrogated the ability of cardiac glycosides and Apo2L/TRAIL to induce apoptosis in an additive manner. To our knowledge, this is the first demonstration that glycosides up-regulate DR4 and DR5, thereby reverting the resistance of lung cancer cells to Apo2/TRAIL-induced apoptosis. Our data suggest that the combination of Apo2L/TRAIL and cardiac glycosides may be a new interesting anticancer treatment strategy.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mast cells (MC) are stem cell factor-dependent tissue-based hematopoietic cells with substantial functional heterogeneity. Cord blood-derived human MC (hMC) express functional receptors for IL-5, and IL-5 mediates stem cell factor-dependent comitogenesis of hMC in vitro. Although IL-5 is not required for normal hMC development, we considered that it might prime hMC for their high-affinity Fc receptor for IgE (FcɛRI)-dependent generation of cytokines, as previously demonstrated for IL-4. Compared with hMC maintained in stem cell factor alone, hMC primed with IL-5 expressed 2- to 4-fold higher steady-state levels of TNF-α, IL-5, IL-13, macrophage inflammatory protein 1α, and granulocyte-macrophage colony-stimulating factor transcripts 2 h after FcɛRI crosslinking and secreted 2- to 5-fold greater quantities of the corresponding cytokines, except IL-13, at 6 h. Unlike IL-4, IL-5 priming did not enhance FcɛRI-dependent histamine release. Thus, IL-5 augments cytokine production by hMC by a mechanism distinct from that of IL-4 and with a different resultant profile of cytokine production. These observations suggest a potentially autocrine effect of IL-5 on hMC for amplification of allergic immune responses, in addition to its recognized paracrine effects on eosinophils, and implicate both IL-4 and IL-5 in the modulation of the hMC phenotype.