563 research outputs found
Effect of Pulp Protection Technique on the Clinical Performance of Amalgam Restorations: Three-Year Results
This study evaluated the influence of the pulp protection technique on clinical performance of amalgam restorations after three years, with particular reference to post-operative sensitivity and secondary caries. One hundred and twenty (120) Class II amalgam restorations (68 premolars, 52 molars; 78 MOD, 42 OD/MO) were placed
in 30 participants (four restorations per participant).The restorations were divided into four groups according to the pulp protection technique used: copal varnish; 2% neutral sodium fluoride; adhesive resin and no pulp protection. The parameters evaluated were post-operative sensitivity, staining of the dental structure, tooth
vitality, partial or total loss of the restoration and
secondary caries. One hundred and eight (108)restorations were available for evaluation after three years. No partial or total loss of restorations had occurred; all teeth were vital, no tooth structure staining or secondary caries was detected in any of the restored teeth. Post-operative sensitivity was observed only in two restorations
at baseline and at seven-days. The three year clinical performance of teeth restored with a high copper dispersed phase amalgam was not affected by the choice of pulp protection technique
Performance of Iris pseudacorus and Typha domingensis for furosemide removal in a hydroponic system
The potential of Iris pseudacorus and Typha domingensis to remove the pharmaceutical active compound
(PhAC) Furosemide from a nutrient solution was assessed. Both plants were exposed to
2mg L 1 of furosemide during 21 days and the removal of furosemide was monitored. Vessels
without furosemide were also implemented as control systems for plants development. Likewise,
unplanted vessels with furosemide were employed to assess abiotic removal mechanisms. All vessels
were covered with aluminum foil to avoid photodegradation of the compound. Both plants
showed potential to remove Furosemide, attaining, at the end of the experiment, a removal of
42.0–66.9% and 40.5–57.8%, for Typha and Iris, respectively. The plants do not presented a visible
negative stress response to the exposure to furosemide, having a positive growth rate at the end
of the experiment. Biodegradation seems to play an important role in furosemide removal, being
enhanced by the presence of the plants. The two macrophytes presented different removal behaviors,
particularly in the first 48 h of contact time. FUR removal by Iris follows a pseudo-first order
while by Typha is divide in different phases. These results indicate that different plants species
seem to have different mechanisms to remove pollutants from waterinfo:eu-repo/semantics/publishedVersio
Phosphorus removal by a fixed-bed hybrid polymer nanocomposite biofilm reactor
Eutrophication is one of the main challenges regarding the ecological quality of surface waters, phosphorus bioavailability being its main driver. In this context, a novel hybrid polymer nanocomposite (HPN-Pr) biofilm reactor aimed at integrated chemical phosphorus adsorption and biological removal was conceived. The assays pointed to removal of 1.2 mg P/g of reactive phosphorus and 1.01 mg P/g of total phosphorus under steady-state conditions. A mathematical adsorption–biological model was applied to predict reactor performance, which indicated that biological activity has a positive effect on reactor performance, increasing the amount of reactive phosphorus removed.The authors acknowledge the Portuguese Foundation for Science and Technology for the financial support under Project SFRH/BD/39085/2007
Caracterização da produção agroecológica do sul do Rio Grande do Sul e sua relação com a mecanização agrícola.
A agricultura agroecológica tem-se destacado como uma das alternativas de renda para os pequenos agricultores devido à crescente busca por parte da população por alimentação mais saudável. No Rio Grande do Sul, a Associação Regional de Produtores Agroecológicos da Região Sul (Arpasul), constituída por 48 famílias, é representativa do processo de produção e de comercialização de produtos agroecológicos, servindo como referencial para o presente estudo. O objetivo principal deste trabalho foi o levantamento das necessidades dos produtores agroecológicos
em relação à mecanização agrícola. As informações obtidas foram baseadas no sistema de produção utilizado, sendo caracterizados aspectos referentes à propriedade, às operações agrícolas e às necessidades específicas de máquinas e implementos. Por meio deste estudo, foi evidenciada a carência no atendimento das demandas específicas, na área de máquinas agrícolas para esse segmento, podendo servir como referencial para o desenvolvimento de novas máquinas e/ou aperfeiçoamento das existentes. A semeadora de milho e feijão foi a máquina que a maioria dos agricultores pesquisados indicou como sua maior necessidade
Study of flare energy release using events with numerous type III-like bursts in microwaves
The analysis of narrowband drifting of type III-like structures in radio
bursts dynamic spectra allows to obtain unique information about primary energy
release mechanisms in solar flares. The SSRT spatially resolved images and a
high spectral and temporal resolution allow direct determination not only the
positions of its sources but also the exciter velocities along the flare loop.
Practically, such measurements are possible during some special time intervals
when the SSRT (about 5.7 GHz) is observing the flare region in two high-order
fringes; thus, two 1D scans are recorded simultaneously at two frequency bands.
The analysis of type III-like bursts recorded during the flare 14 Apr 2002 is
presented. Using-muliwavelength radio observations recorded by SSRT, SBRS,
NoRP, RSTN we study an event with series of several tens of drifting microwave
pulses with drift rates in the range from -7 to 13 GHz/s. The sources of the
fast-drifting bursts were located near the top of the flare loop in a volume of
a few Mm in size. The slow drift of the exciters along the flare loop suggests
a high pitch-anisotropy of the emitting electrons.Comment: 16 pages, 6 figures, Solar Physics, in press, 201
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