Changes over time in canine retraction: An implant study

Introduction: The objective of this study was to analyze rates of canine movement over the first 2 months of continuous retraction, when rate changes are expected. Methods: Ten patients with bone markers placed in the maxilla and the mandible had their canines retracted over a 2-month period. Retraction was accomplished with beta-titanium alloy T-loop springs. Standardized 45 degrees oblique cephalograms where taken initially and every 28 days thereafter. The radiographs were scanned and digitized twice (the average was used for the analyses). The radiographs were superimposed by using the bone markers and oriented on the functional occlusal plane. Paired t tests were used to compare side and jaw effects. Results: There were no significant differences between sides. The maxillary cusp was retracted 3.2 mm, with less movement during the first (1.1 mm) than during the second 4 weeks (2.1 mm). The maxillary apices did not move horizontally. There were no significant vertical movements in the cusps and apices of the maxillary canines. The mandibular cusp was retracted 3.8 mm-1.1 mm during the first and 2.7 mm during the second 4 weeks. The mandibular apices were protracted 1.1 mm. The cusps and apices were intruded 0.6 and 0.7 mm, respectively. The only difference between jaws was the greater protraction of the mandibular apices during the second 4 weeks and in overall movement. Conclusions: The rate of canine cusp retraction was greater during the second than the first 4 weeks. The mandibular canines were retracted by uncontrolled tipping whereas the maxillary canines were retracted by controlled tipping. (Am J Orthod Dentofacial Orthop 2009; 136: 87-93)

DETECTION of MOGIBACTERIUM TIMIDUM IN SUBGINGIVAL BIOFILM of AGGRESSIVE and NONDIABETIC and DIABETIC CHRONIC PERIODONTITIS PATIENTS

The aim of the present study was to evaluate the frequency of detection of Mogibacterium timidum in subgingival samples of subjects with generalized aggressive periodontitis (GAgP) and uncontrolled diabetic and non-diabetic subjects with generalized chronic periodontitis (GChP). 48 patients with GAgP, 50 nondiabetic and 39 uncontrolled (glycated hemoglobin >7%) type 2 diabetic subjects with GChP were enrolled in this study. Subgingival biofilm were collected from deep pockets (probing depth > 7 mm). After DNA extraction, M. timidum was detected by Nested Polymerase Chain Reaction and chi-square test was used to data analysis (p>0.05). There were no differences in the frequency of detection of M. timidum between subjects with GAgP (35%) and non-diabetic subjects with GChP (40%) (p>0.05). The frequency of detection of M. timidum was significantly higher in deep pockets of diabetic subjects with GChP (56%) when compared to GAgP (p<0.05), but similar to non-diabetic subjects with GChP (p>0.05). The frequency of detection of M. timidum was higher in subjects GChP presenting uncontrolled type 2 diabetes mellitus, when compared to GAgP subjects.

Group A T-loop for differential moment mechanics: An implant study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hydrological aspects of the tropical rainforest in the central Amazon.

Annual runoff, loss by interception, transpiration and evapotranspiration of two watersheds in the Amazon rainforest of the terra firme type in central Amazonia, were estimated. The results show the significant importance of the forest to the present ecological balance of the region, which may be seriously altered if uncontrolled and unplanned deforestation continues.-from Authors

Java applets for a WWW-HTML-based course in power electronics

This paper introduces Java applet programs for a WWW (world wide web)-HTML (hypertext markup language)-based multimedia course in Power Electronics. The applet programs were developed with the purpose of providing an interactive visual simulation and analysis of idealized uncontrolled single-phase, and three-phase rectifiers. In addition, this paper discusses the development and utilization of JAVA applet programs to solve some design-oriented equations for rectifier applications. The major goal of these proposed JAVA applets was to provide more facilities for the students increase their pace in Power Electronics course, emphasizing waveforms analysis, and providing conditions for an on-line comparative analysis among different hands-on laboratory experiences, via a normal Internet TCP/IP connection. Therefore, using the proposed JAVA applets, which were embedded in a WWW-HTML-based course in Power Electronics, was observed an important improvement of the apprenticeship for the content of this course. Therefore, the course structure becomes fluid, allowing a true on-line course over the WWW, motivating students to learn its content, and apply it in some applications-oriented projects, and their home-works.

Temperature analysis during bonding of brackets using LED or halogen light base units

The purpose of our investigation is to compare the intrapulpal temperature changes following blue LED system and halogen lamp irradiation at the enamel surface of permanent teeth. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Several light sources can be used: halogens, arc plasma, lasers, and recently blue LED systems. An important aspect to be observed during such a procedures is the temperature change. In this study, we have used nine human extracted permanent teeth: three central incisors, three lateral incisors, and three canines. Teeth were exposed to two light sources: blue LED system (preliminary commercial model LEC 470-II) and halogen lamp (conventional photo-cure equipment). The surface of teeth was exposed for 20, 40, and 60 sec at the buccal and lingual enamel surface with an angle of 45 degrees. Temperature values measured by a thermistor placed at pulpar chamber were read in time intervals of 1 sec. We obtained plots showing the temperature evolution as a function of time for each experiment. There is a correlation between heating quantity and exposition time of light source: with increasing exposition time, heating increases into the pulpal chamber. The halogen lamp showed higher heating than the LED system, which showed a shorter time of cooling than halogen lamp. The blue LED system seems like the indicated light source for photo-cure of composite resin during the bonding of brackets. The fixation of brackets using composite resin is more comfortable and faster when using a photo-curable composite. Blue LED equipment did not heat during its use. This could permit a shorter clinical time of operation and better performance. © Mary Ann Liebert, Inc.

Educational Java applets get in power electronics labs

This paper presents Java applet programs for a WWW (world wide web)-HTML (hypertext markup language)-based multimedia course in basic power electronics circuits. These tools make use of the benefits of Java language to provide a dynamic and interactive approach to simulate steady-state idealized rectifiers (uncontrolled and controlled; single-phase and three-phase). In addition, this paper discusses the development and the use of the Java applet programs to assist the teaching of basics rectifier power electronics circuits, and to serve as a first design tool for basics power electronics circuits in the experiments of the laboratories. In order to validate the developed simulation applets, the results were confronted with results obtained from a well-know simulator package PSPICE. © 2005 IEEE.

Search for associated Higgs boson production WH→WWW *→l±νl′±ν′+X in pp̄ collisions at s=1.96TeV

We present a search for associated Higgs boson production in the process pp̄→WH→WWW*→l±νl′±ν′ +X in final states containing two like-sign isolated electrons or muons (e±e±, e±μ±, or μ±μ±). The search is based on D0 run II data samples corresponding to integrated luminosities of 360-380pb-1. No excess is observed over the predicted standard model background. We set 95% C.L. upper limits on σ(pp̄→WH) ×Br(H→WW*) between 3.2 and 2.8 pb for Higgs boson masses from 115 to 175 GeV. © 2006 The American Physical Society.

Setting the preheating process of electronic ballasts for hot-cathode fluorescent lamps, considering the Rh/Rc ratio

This paper presents a new model for the representation of the electrodes filaments of fluorescent lamps, during their preheating, and an analysis capable to guide the design of the preheating process in electronic ballasts. The main improvement obtained with the lamp model is the accurate theoretical reproduction of the behavior of the Rh/Rc ratio during the preheating process. In addition, using the proposed methodology based on the lamp model, it is possible to set a proper preheating process to the electrodes filaments, without the necessity of exhaustive empirical adjustments in the prototype, reducing time and costs involved in the design of ballasts with preheating capabilities. © 2006 IEEE.

Atividade mutagênica de plantas medicinais

The number of studies of genotoxic activity of medicinal plants has been growing alongside with their increasing therapeutic use and scientific interest in proving their effectiveness for a variety of pharmacological purposes. This reflects the fact that many of the plants used by great numbers of people, in spite of their proven pharmacological value, can also cause harmful changes in the DNA. The risks are greater when alternative treatments are applied in an uncontrolled way, without due attention to correct botanical identification, to the part of the plant that should to be used and to the method of preparation and administration. In this review, aspects of the mutagenic activity of some medicinal plants are discussed.

Comparison between inverted and unprocessed digitized radiographic imaging in periodontal bone loss measurements

The advances in digital imaging technology in dentistry have provided an alternative to film-based radiography and have given new options to detect periodontal bone loss. The purpose of this study was to compare inverted and unprocessed digitized radiographic imaging in periodontal bone loss measurements. Thirty-five film-based periapical radiographs of patients suffering from moderate to advanced untreated periodontal bone loss associated to lower premolar and molars was selected from the department files, with 40 bone loss areas. The film-based radiographs were digitized with a flatbed scanner with a transparency and radiograph adapter used for transilluminating the radiograph imaging. Digitization was performed at 600 dpi and in gray scale. The images were digitized using Image Tool software by applying image inversion, that is, transformation of radiopaque structures into radiolucent structures and vice-versa. The digital data were saved as JPEG files. The images were displayed on a 15-inch and 24-bit video monitor under reduced room lighting. One calibrated examiner performed all radiographic measurements, three times, from the cementoenamel junction to the most apical extension of the bone loss, in both types of image (inverted and unprocessed). Brightness and contrast were adjusted according to the examiner's individual demand. Intraclass correlation coefficient was used to compare the measurements from both types of images. The means of radiographic measurements, in mm, for inverted and unprocessed digitized imaging were 6.4485 and 6.3790, respectively. The intraclass correlation coefficient was significant (0.99) The inverted and unprocessed digitized radiographic images were reliable and there was no difference in the diagnostic accuracy between these images regarding periodontal bone loss measurements.

A true programmable HPF hybrid three-phase rectifier

In this paper is proposed and analyzed a digital hysteresis modulation using a FPGA (Field Programmable Gate Array) device and VHDL (Hardware Description Language), applied at a hybrid three-phase rectifier with almost unitary input power factor, composed by parallel SEPIC controlled single-phase rectifiers connected to each leg of a standard 6-pulses uncontrolled diode rectifier. The digital control allows a programmable THD (Total Harmonic Distortion) at the input currents, and it makes possible that the power rating of the switching-mode converters, connected in parallel, can be a small fraction of the total average output power, in order to obtain a compact converter, reduced input current THD and almost unitary input power factor. The proposed digital control, using a FPGA device and VHDL, offers an important flexibility for the associated control technique, in order to obtain a programmable PFC (Power Factor Correction) hybrid three-phase rectifier, in agreement with the international standards (IEC, and IEEE), which impose limits for the THD of the AC (Alternate Current) line input currents. Finally, the proposed control strategy is verified through experimental results from an implemented prototype. ©2008 IEEE.

Hybrid three-phase HPF rectifier with programmable input current THD, using FPGA device and VHDL language

In this paper is proposed and analyzed a digital hysteresis modulation using a FPGA (Field Programmable Gate Array) device and VHDL (Hardware Description Language), applied at a hybrid three-phase rectifier with almost unitary input power factor, composed by parallel SEPIC controlled single-phase rectifiers connected to each leg of a standard 6-pulses uncontrolled diode rectifier. The digital control allows a programmable THD (Total Harmonic Distortion) at the input currents, and it makes possible that the power rating of the switching-mode converters, connected in parallel, can be a small fraction of the total average output power, in order to obtain a compact converter, reduced input current THD and almost unitary input power factor. Finally, the proposed digital control, using a FPGA device and VHDL, offers an important flexibility for the associated control technique, in order to obtain a programmable PFC (Power Factor Correction) hybrid three-phase rectifier, in agreement with the international standards (IEC, and IEEE), which impose limits for the THD of the AC (Alternate Current) line input currents. The proposed strategy is verified by experiments. © 2008 IEEE.