Scanning electron microscopic and profilometric study of different sharpening stones

Scaling and root planing contribute to the recovery of periodontal health. All periodontal instruments loose their fine cutting angle after use. To maintain this angle, correct sharpening is required using specifically designed stones. The characteristics of sharpening stones can be compared to the blade of the instruments and also transported to root surface during instrumentation. Root smoothness is related to the quality of the blade. Therefore, the purpose of this study was to evaluate the characteristics of 9 sharpening stones by scanning electron microscopic and profilometric analyses. Ceramic and Neumar stones were very fine and both may be recommended to maintain the sharpness of the instruments. Arkansas, Thompson and CE stones presented greater roughness with very regular and round particles, and are suitable for maintenance of the cutting angle. In addition, these stones may be indicated for the routine sharpening of the instruments that are partly dull. Oxide Aluminum, Carborundum and JON stones were the coarsest with large irregular particles and may be indicated for initial sharpening of totally dull instruments with completion of sharpening with finer stones.

Morfo-anatomia do eixo vegetativo aéreo de Achyrocline alata (Kunth) DC. (Asteraceae)

Achyrocline alata occurs in a dense and low vegetation in Mato Grosso do Sul State, Brazil and it has been studied under physical-chemical and yield aspects, being scarce anatomical data. The present work has as objective the study of the aerial vegetative axis. Stem is cylindrical and hairy, having five wings, which are arisen from their leaves. The blade shows the presence of uniseriate epidermis, which is covered by the cuticle of variable thickness; and non-glandular and glandular trichomes. The non-glandular trichomes are uniseriate and multicellular and have their apex cell in whip form, while the glandular trichomes are multicellular, uniseriate or biseriate. The mesophyll is dorsiventral with uni-stratified palisade parenchyma in most of the cases and lacunal parenchyma formed by three to four layers of irregular cells. Only one collateral vascular bundle occurs in the midvein. Stem in transversal section is covered by epidermis with trichomes similar to leaves; the cortex is constituted by a discontinuous area of angular collenchyma, which is followed by chlorophyll parenchyma. Vascular cylinder that is delimited by pericycle shows vascular bundles of collateral type. In the secondary structure, the periderm is originated from epidermal and subepidermal tissues. In vascular region, the fascicular cambium differs into secondary xylem and phloem, while interfascicular cambium produces sclerenchymatous tissue.

Desempenho ponderal de novilhas mestiças Holandês x Zebu submetidas a duas estratégias de suplementação mineral

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Root surface treatment with vitamin C in tooth replantation: microscopic study in rats

AIM: Late tooth replantation is a worthy procedure, especially in growing patients, being the best option for tooth avulsion. This study evaluated the effects of root surface treatment with 2% acidulated phosphate sodium fluoride and effervescent vitamin C (Redoxon) in late replantation. METHODS: Twenty rat teeth (Rattus norvegicus, albinus, Wistar) were extracted and left on a table for 6 h. Then, the dental papilla and enamel organ were sectioned and the pulp was removed through the apex. After removal of the periodontal ligament with a blade, the animals were divided into 2 groups: Group I teeth were immersed in 2% acidulated phosphate sodium fluoride solution for 10 min and obturated with Ca(OH)(2) paste. Group II teeth were immersed in effervescent vitamin C solution (Redoxon 2 g) for 10 min and obturated as for Group I. After these procedures, teeth were replanted and animals were killed after 60 days. RESULTS: The study revealed a larger amount of replacement resorption in Group I and larger amount of ankylosis in Group II, with statistically significant difference and absence of inflammatory resorption. CONCLUSION: The substances used for root surface treatment were unable to prevent replacement resorption and ankylosis, which are expected when the periodontal ligament has been lost.

Mechanical behavior of isolated intervertebral disc

The study on several components of intervertebral joints is essential to understand the spine's degenerative mechanisms and to assess the best method for their treatment. For such study it is necessary to know the mechanical properties of the isolated intervertebral disc (ID) mechanical properties and, it is necessary to evaluate its stresses and strains. In order to assess the ID displacements, a fine, U-shaped blade was developed, over which two extensometers connected in a Wheatstone bridge were placed. The device was then tested on porcine spine ID, where compression loads were applied and the extremities displacements of the blade coupled to the intervertebral disc were measured. Stress/strain diagram, both on the compression and on the decompression phases, evidencing the non-linear nature of such relationship. With the experiment, it was possible to obtain approximate values of the longitudinal elasticity module (E) of the disc material and of the Poisson coefficient (n ). After several tests, E results are compatible with those obtained by others studies, with very simple and low-cost device. This experiments can be used for obtained others mechanical properties of isolated ID with precision and accuracy.

Potenciais de água no solo na produção de alface

The scope of this experiment is to study the influence of soil water potential on lettuce productivity, particularly in relation to deficit and excess of water. Four lettuce cultivars (Americana, Roxa, Crespa and Mimosa), four minimum soil water potential (-0,001, -0,005, -0,012 and 0,022 MPa) and three replicates in experimental randomized design. The results allowed concluding that the -0,012 MPa has the tendency to produce the highest green mass among her soil water potential applied. The Mimosa showed the tendency to produce the highest evapotranspiration among the cultivars. The cultivars Americana e -0,05 MPa was the best combination (148,33g) the worst was the Roxa and -0,022 MPa minimum soil water potential.

Estrutura do capim-braquiária durante o diferimento da pastagem

This experiment was performed aiming to evaluate tiller population density, forage mass and its morphological components on pastures of Brachiaria decumbens cv. Basilisk. during deferment. The treatments encompassed four deferred grazing periods (18, 46, 74 and 121 days). A randomized block design with two replications was used. The numbers of vegetative tillers (VT), reproductive tillers (RT) and dead tillers (DT) in the pasture were determined. The masses of green leaf blade (GLBM), dead stem (DSM) and dead forage (DFM) were also determined. There was a reduction in the number of VT (from 1, 491 to 944 tiller m-2) during the deferment period. RT and DT numbers were not influenced by the deferment periods. Their averages were 211 and 456 tiller m-2, respectively. Longer deferring periods resulted in an increase in GSM (from 2, 965 to 4, 877 kg ha-1 of dry mass) and DFM (from 2, 324 to 4, 823 kg ha-1 of dry mass), but it did not influence GLBM (average of 2, 047 kg ha-1 of dry mass). In Viçosa, Minas Gerais State Brazil, Brachiaria decumbens cv. Basilisk pasture fertilized and deferred in the beginning of March must be kept deferred for about 70 days in order to conciliate both quality and quantity forage production.

Modelo experimental de úlcera traumática em mucosa jugal de ratos

Purpose: To establish an experimental model of traumatic ulcer in rat cheek mucosa for utilization in future alternative therapy studies. Methods: A total of 60 adult male rats (250 - 300g) were used. Ulceration of the left cheek mucosa was provoked by abrasion using a n o 15 scalpel blade. The animals were observed for 10 days, during which they were weighed and their ulcers were measured. The histological characteristics were analyzed and scored according to the ulcer phase. In the statistical analysis, a value of p<0.01 was considered a statistically significant response in all cases. Results: During the five first days, the animals lost weight (Student t test, p<0.01). The ulcerated area receded linearly over time and was almost completely cicatrized after 10 days (ANOVA, Tendency post-test, p<0.0001). Groups on days 1, 2 and 3 days displayed similar results, but a decrease in scores were observed after the 4th day. Conclusion: The proposed cheek mucosa ulcer model in rats can be considered an efficient, low-cost, reliable, and reproducible method.

Monoclonal Antibody Production and Immunolocalization of a Salinity Stress-Related Protein in Rice (Oryza sativa)

Among various physiological responses to salt stress, the synthesis of a lectin-related protein of 14.5 kDa was observed in rice plants (Oryza sativa L.) under the treatment of 170 mmol/L NaCl. In order to better understand the role of the SALT protein in the physiological processes involving salinity, it was immunolocalized in mesophilic cells of leaf sheath and blade of a rice variety IAC-4440 following monoclonal antibodies produced by hybridome culture technique. This variety turned out to be an excellent model for that purpose, since it accumulates SALT protein even in absence of salt treatment and it has been classified as moderately sensitive to salinity and a superior grain producer. This feature was relevant for this work since it allowed the use of plants without the deleterious effects caused by salinity. Immunocytochemistry assays revealed that the SALT protein is located in the stroma of chloroplasts under non-stressing condition. Since the chloroplast is the main target affected by salinity and considering that the SALT protein does not present any apparent signal peptide for organelle localization, its lectin-like activity seems to play an important role in the establishment of stable complexes, either to other proteins or to oligosaccharides that are translocated to the chloroplast. © 2011 China National Rice Research Institute.

Evaluation of the anti-resorptive ability of an experimental acetazolamide paste for the treatment of late replanted teeth: A study in rats

When late replantation is performed, the root surface and root canal should be treated. Notwithstanding failures still occur, because of the high rates of root resorption, evidencing the need to search for substances that may inhibit root resorption. The acetazolamide is a known anti-resorptive agent, and its use as root canal dressing may increase the success rates in the treatment of root resorption. Therefore, this study evaluated the effect of an acetazolamide paste used as root canal dressing in late replanted teeth. The study was conducted on 24 maxillary right incisors of rats, which were avulsed and divided in two groups. In group I, the teeth were kept dry for 30min, had their root surfaces rubbed with a blade, and were treated with 2% sodium fluoride at pH 5.5 for 20min; the root canals were instrumented and filled with acetazolamide paste; and then the teeth were replanted. In group II, the treatment was similar to group I, except for the root canal dressing, with utilization of calcium hydroxide in group II. At 15 and 60days after replantation, the animals were killed and the specimens were processed in a histotechnical laboratory for microscopic and morphometric analysis. The results demonstrated the ability of both intracanal substances to limit root resorption, yet they were unable to completely inhibit the root resorption. Replacement resorption lacunae were present in greater proportion in group II, at 60days. It was concluded that the acetazolamide paste was effective to limit the root resorption, being more effective in limiting the replacement resorption compared with calcium hydroxide. © 2012 John Wiley & Sons A/S.

Anatomia radicial de Mormodes sinuata Rchb. f. & Warm.; (Catasetinae, Cymbidieae: Orchidaceae)

Since there is a lack of information on the root organization of the sub-tribe Catasetinae, current research describes the anatomy of Mormodes sinuata roots and indicate adaptations related to water provision and other taxonomical traits. Five roots of three plants, cut at the median region with a blade, were fixed and preserved in alcohol 5%. Cuts were stained by saffron blue 0.05% and mounted in glycerin. Although the roots have structural characteristics adapted to epiphytism, some anatomic characteristics demonstrate that the species requires more watering or wetter environments when compared with other types of Catasetinae. Root anatomic characteristics foreground results by authors who include the sub-tribe Catasetinae within the tribe Cymbidieae. Further, anatomic characteristics have a generic uniformity and are a tool for the genus's systematics.

Paratrichodina africana (Ciliophora): A pathogenic gill parasite in farmed Nile tilapia

Trichodinids are ciliated protozoa that are widely known as one of the main groups of fish parasites. The genus Trichodina presents the greatest species diversity. However, records of Paratrichodina species are scarce, and little is known about their pathogenicity in hosts. The present study provides new records of Paratrichodina africana Kazubski and El-Tantawy (1986) in Nile tilapia from South America and descriptions of pathological changes and seasonality. A total of 304 farmed fish were examined. From gill scraping, parasites were identified using Klein's nitrate impregnation method. Gill samples were fixed for histopathological analysis. Small trichodinid found in this study have a prominent blade apophysis and narrow central part and blade shape that corresponds to the characteristics of P. africana Kazubski and El-Tantawy (1986). Gill lesions were proportional to parasite intensity, in which the gill tissue was compromised in heavy infestation. Proliferative disturbances were found, including epithelial hyperplasia, desquamation, and mononuclear and eosinophilic infiltrate that culminated in necrosis. We did not observe a seasonality effect on the occurrence of P. africana. This ciliated protozoan causes compromised respiratory capacity that leads to severe gill lesions and currently is an important pathogen that afflicts intensive tilapia cultures in Brazil. © 2013 Elsevier B.V.

Características anatômicas foliares e controle químico em pós-emergência de Brachiaria decumbens e Brachiaria plantaginea

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracteres estruturais e dimensão fractal da folha de espécies de Arachis e sua relação com a cercosporiose

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Remoção mecânica do ligamento periodontal cementário necrosado com escova de Robinson e pedra pomes e com lâmina de bisturi. Análise histomorfométrica e MEV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)