Evaluation Of The Risk Of A Stripping Perforation With Gates-glidden Drills: Serial Versus Crown-down Sequences

The aim of this study was to evaluatte the remaining dentine/cementum thickness using Gates-Glidden burs in serial and crown-down sequences and to observe which of the two sequences is the safest for preparing mesial roots of molars. Thirty-six left and. right human mandibular first molars were selected. Standard access cavities were made and initially explored with Flexofiles sizes 10 and 15 until the tip was visible at the apex. The teeth were embedded in a muffle speqially developed for this study using a PVC tube with two parallel metal rods An its lid. Each tooth-block was sectioned 3 mm apically to the furcation using a low-speed saw with a diamond disc. The tooth-block was examined under a microscope and an initial image was captured by a digital video system with 8 X and 12 X magnifications. Finally, the tooth-blocks were reassembled in the muffle so that the canals could be instrumented. After instrumentation the area of each mesial canal as well as the smallest distance to the root furcation were measured again. The mesio-buccal canals (crown-down order) and the mesio-lingual canals (serial sequence) presented an average area of 0.46 ± 0.16 mm2 and 0.88 ± 0.27 mm2 (P < 0.01), respectively. The mean values of the smallest distance to the furcation for the mesio-buccal and mesio-lingual canals were 0.66 ± 0.19 mm and 0.39 ± 0.13 mm (P < 0.01), respectively. The remaining dentine/cementum thickness using Gates-Glidden burs was greater in the crown-down sequence than in the serial sequence.2211824Grossman, L., A brief history of endodontics (1982) J Endod, 8 (1), p. 538Mullaney TP. Instrumentation of finely curved canals. Dent Clin North Am. l979;23(4):575-92Taintor, J.F., Use of the gates glidden bur in endodontics (1978) J Nebr Dent Assoc, 54 (3), pp. 10-12Weine, F.S., Kelly, R.E., Lio, P.J., The effect of preparation procedures on original canal shape and on apical foramen shape (1975) J Endod, 1 (8), pp. 255-262Abou-Rass, M., Frank, A.L., Glick, D.H., The anticurvature filing method to prepare the curved root canal (1980) J Am Dent Assoc, 101 (5), pp. 792-794Cunningham, C.J., Senia, S.E., A three-dimensional study of canal curvatures in the mesial roots of mandibular molars (1992) J Endod, 18 (6), pp. 294-300Coutinho-Filho.T, De-Deus G, Guimarães T, Gurgel-Filho ED, Maniglia-Ferreira C. A computer evaluation of the dentin remaining after cervical preparation in curved canals: Gatesglidden drills vs. orifice shaper. Braz J Oral Sci. 2002;1(3):116-20Lim, S.S., Stock, C.J., The risk of perforation in the curved canal: Anticurvature filing compared with the step-back technique (1987) Int Endod J, 20 (1), pp. 33-39Isom, T.L., Marshall, J.G., Baumgartner, J.C., Evaluation of root thickness in curved canals after flaring (1995) J Endod, 21 (7), pp. 368-371Gluskin, A.H., Brown, D.C., Buchanan, L.S., A reconstructed computerized tomographic comparison of Ni-Ti rotary GT files versus traditional instruments in canals shaped by novice operators (2001) Int Endod J, 34 (6), pp. 476-484Schilder, H., Cleaning and shaping the root canal (1974) Dent Clin North Am, 18 (2), pp. 269-296Bramante, C.M., Berbet, A., Borges, R.P., A methodology for evaluation of root canal instrumentation (1987) J Endod, 13 (5), pp. 243-245Bower, R.C., Furcation morphology relative to periodontal treatment. Furcation entrance architecture (1979) J Periodontol, 50 (1), pp. 23-27Kessler, J.R., Peters, D.D., Lorton, L., Comparison of the relative risk of molar root perforations using various endodontic instrumentation techniques (1983) J Endod, 9 (10), pp. 439-447McCann, J.T., Keller, D.L., LaBounty, G.L., A modification of the muffle model system to study root canal morphology (1990) J Endod, 16 (3), pp. 114-115Pilo, R., Corcino, G., Tamse, A., Residual dentin thickness in mandibular premolars prepared with hand and rotatory instruments (1998) J Endod, 24 (6), pp. 401-404Torabinejad, M., Rotstein, L., Stabholz, A., Effect of preflaring on tactile detection of the apical constriction (1995) J Endod, 21 (2), pp. 92-94West JD, Roane JB. Limpeza e modelagem do sistema de canais radiculares. In: Cohen S, Burns RC. Caminhos da polpa. 7th ed. Rio de Janeiro: Guanabara Koogan2000. p. 206-36Abou-Rass, M., Jastrab, R.J., The use of rotary instruments as auxiliary aids to root canal preparation of molars (1982) J Endod, 8 (2), pp. 78-7

The structure and dynamics of young star clusters: King 16, NGC 1931, NGC 637 and NGC 189

In this paper, using 2MASS photometry, we study the structural and dynamical properties of four young star clusters viz. King 16, NGC 1931, NGC 637 and NGC 189. For the clusters King 16, NGC 1931, NGC 637 and NGC 189, we obtain the limiting radii of 7', 12', 6' and 5' which correspond to linear radii of 3.6 pc, 8.85 pc, 3.96 pc and 2.8 pc respectively. The reddening values $E(B-V)$ obtained for the clusters are 0.85, 0.65--0.85, 0.6 and 0.53 and their true distances are 1786 pc, 3062 pc, 2270 pc and 912 pc respectively. Ages of the clusters are 6 Myr, 4 Myr, 4 Myr and 10 Myr respectively. We compare their structures, luminosity functions and mass functions ($\phi(M) = dN/dM \propto M^{-(1+\chi)}$) to the parameter $\tau = t_{age}/t_{relax}$ to study the star formation process and the dynamical evolution of these clusters. We find that, for our sample, mass seggregation is observed in clusters or their cores only when the ages of the clusters are comparable to their relaxation times ($\tau \geq 1$). These results suggest mass seggregation due to dynamical effects. The values of $\chi$, which characterise the overall mass functions for the clusters are 0.96 $\pm$ 0.11, 1.16 $\pm$ 0.18, 0.55 $\pm$ 0.14 and 0.66 $\pm$ 0.31 respectively. The change in $\chi$ as a function of radius is a good indicator of the dynamical state of clusters.Comment: Accepted for publication in Astrophysics & Space Scienc

The Brazilian Developments On The Regional Atmospheric Modeling System (brams 5.2): An Integrated Environmental Model Tuned For Tropical Areas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS), in which different previous versions for weather, chemistry, and carbon cycle were unified in a single integrated modeling system software. This new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. The description of the main model features includes several examples illustrating the quality of the transport scheme for scalars, radiative fluxes on surface, and model simulation of rainfall systems over South America at different spatial resolutions using a scale aware convective parameterization. Additionally, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America, are shown. Atmospheric chemistry examples show the model performance in simulating near-surface carbon monoxide and ozone in the Amazon Basin and the megacity of Rio de Janeiro. For tracer transport and dispersion, the model capabilities to simulate the volcanic ash 3-D redistribution associated with the eruption of a Chilean volcano are demonstrated. The gain of computational efficiency is described in some detail. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near-surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding both its functionalities and skills are discussed. Finally, we highlight the relevant contribution of this work to building a South American community of model developers. © Author(s) 2017.1011892222014/01563-1, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2014/01564-8, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2015/10206-0, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo306340/2011-9, Conselho Nacional de Desenvolvimento Científico e TecnológicoFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Comparison Between Conventional Intervention and Non-immersive Virtual Reality in the Rehabilitation of Individuals in an Inpatient Unit for the Treatment of COVID-19: A Study Protocol for a Randomized Controlled Crossover Trial.

Background: The new human coronavirus that leads to COVID-19 (coronavirus disease 2019) has spread rapidly around the world and has a high degree of lethality. In more severe cases, patients remain hospitalized for several days under treatment of the health team. Thus, it is important to develop and use technologies with the aim to strengthen conventional therapy by encouraging movement, physical activity, and improving cardiorespiratory fitness for patients. In this sense, therapies for exposure to virtual reality (VR) are promising and have been shown to be an adequate and equivalent alternative to conventional exercise programs. Aim: This is a study protocol with the aim of comparing the conventional physical therapy intervention with the use of a non-immersive VR software during COVID-19 hospitalization. Methods: Fifty patients hospitalized with confirmed diagnosis of COVID-19 will be divided in two groups under physiotherapy treatment using conventional or VR intervention: Group A: participants with COVID-19 will start the first day of the protocol with VR tasks in the morning and then in the second period, in the afternoon, will perform the conventional exercises (n = 25) and Group B: participants with COVID-19 will start the first day with conventional exercises in the morning and in the second period, in the afternoon, will perform activity with VR (n = 25). All participants will be evaluated with different motor and physiologic scales before and after the treatment to measure improvements. Conclusion: Considering the importance of benefits from physical activity during hospitalization, VR software shows promise as a potential mechanism for improving physical activity. The results of this study may provide new insights into hospital rehabilitation. Trial Registration: ClinicalTrials.gov, identifier: NCT04537858. Registered on 01 September 2020

Reclamation status of a degraded pasture based on soil health indicators

Pasture degradation is a concern, especially in susceptible sandy soils for which strategies to recover them must be developed. Microbiological and biochemical soil health indicators are useful in the guindace of soil management practices and sustainable soil use. We assessed the success of threePanicum maximum Jacq. cultivars in the reclamation of a pasture in a sandy Typic Acrudox in the northwest of the state of Paraná, Brazil, based on soil health indicators. On a formerly degraded pasture withUrochloa brizantha (Hochst. ex A. Rich.) R.D. Webster, a trial with threeP. maximum (cv. Massai, Tanzânia, or Mombaça) was conducted. Lime and phosphate were applied at set-up, and mineral N and K as topdressing. A remnant of degraded pasture adjacent to the trial was used as control. Twenty-three chemical, physical, microbiological and biochemical attributes were assessed for the 0-10 cm topsoil. The procedures for reclamation improved most of the indicators of soil health in relation to the degraded pasture, such as soil P, mineral N, microbial biomass C, ammonification rate, dehydrogenase activity and acid phosphatase. CO2 evolution decreased, whereas microbial biomass C increased in the pasture under reclamation, resulting in a lower metabolic quotient (qCO2) that points to a decrease in metabolic stress of the microbial community. The reclamation of the pasture withP. maximum, especially cv. Mombaça, were evidenced by improvements in the microbiological and biochemical soil health indicators, showing a recovery of processes related to C, N and P cycling in the soil