Influência da sequência técnica do sistema K3 Endo na segurança e rapidez do preparo de canais curvos simulados

O objetivo do presente trabalho foi comparar duas sequências diferentes na rapidez e segurança no preparo de canais curvos simulados. Foram empregados 30 blocos de acrílico com canais simulados que foram divididos em Grupo 1 – La Axxess 20 e 35/.06 25/.06, 20/.06, 25/.04 e 20/.04 e Grupo 2 – K3 Universal (VTVT) – 25/.10, 25/.08, 35/.06, 30/.04, 25/.06 e 20/.04. No preparo de todos os blocos empregou-se a velocidade de 250 rpm e torque de 1.4N/cm. Foram confeccionados dois pontos externos de amálgama para mensuração do desvio e adotou-se 17 mm como comprimento de trabalho. No Grupo 1, dilatou-se até o instrumento 25/.04, enquanto que no Grupo 2 até o 25/.06, e cronometrou-se o tempo de preparo de cada bloco. Na análise do desvio, radiografias com lima k 15 (antes) e K 25 (depois) foram realizadas e digitalizadas, medindo-se o ângulo antes e depois no programa Digora for Windows 1.51. Os dados foram comparados pelo teste T-Student e Mann-Whitney. Os resultados mostraram que em ambas as técnicas não ocorreram diferenças significantes entre o ângulo antes e depois e que não ocorreu diferença significante entre os desvios médios do Grupo 1 (0,130) e do Grupo 2 (1,330). No tempo de preparo, o Grupo 1 foi significantemente mais rápido que o Grupo 2. No Grupo 1, ocorreu a fratura de 1 instrumento, enquanto que no Grupo 2 ocorrerem duas fraturas. Concluiu-se que ambas as técnicas são seguras para o preparo de canais simulados curvos, sendo que no Grupo 1 o tempo de preparo é menor.

Preparation and a time-resolved fluoroimmunoassay application of new europium fluorescent nanoparticles

New silica-based europium fluorescent nanoparticles having surface amino groups were prepared by a covalent binding-copolymerization technique. In the nanoparticles, the fluorescent Eu3+ chelate molecules were covalently bound to silicon atoms to protect the nanoparticles from dye leaking in bio-applications. The amino groups on the surface of nanoparticles made the surface modification and bioconjugation of nanoparticles easier. The nanoparticles were characterized and developed as a new type of fluorescence probe for a highly sensitive time-resolved fluoroimmunoassay (TR-FIA) of human hepatitis B surface antigen (HBsAg).

Bond Strength and Etching Pattern of Adhesive Systems to Enamel: Effects of Conditioning Time and Enamel Preparation

Statement of the problem: The performance of self-etch systems on enamel is controversial and seems to be dependent on the application technique and the enamel preparation. Purpose of the Study: To examine the effects of conditioning time and enamel surface preparation on bond strength and etching pattern of adhesive systems to enamel. Materials and Methods: Ninety-six teeth were divided into 16 conditions (N = 6) in function of enamel preparation and conditioning time for bond strength test. The adhesive systems OptiBond FL (Kerr, Orange, CA, USA), OptiBond SOLO Plus (Kerr), Clearfil SE Bond (Kuraray, Osaka, Japan), and Adper Prompt L-Pop (3M ESPE, St. Paul, MN, USA) were applied on unground or ground enamel following the manufacturers` directions or doubling the conditioning time. Cylinders of Filtek Flow (0.5-mm height) were applied to each bonded enamel surface using a Tygon tube (0.7 mm in diameter; Saint-Gobain Corp., Aurora, OH, USA). After storage (24 h/37 degrees C), the specimens were subjected to shear force (0.5 mm/min). The data were treated by a three-way analysis of variance and Tukey`s test (alpha = 0.05). The failure modes of the debonded interfaces and the etching pattern of adhesives were observed using scanning electron microscopy. Results: Only the main factor ""adhesive"" was statistically significant (p < 0.001). The lowest bond strength value was observed for OptiBond FL. The most defined etching pattern was observed for 35% phosphoric acid and for Adper Prompt L-Pop. Mixed failures were observed for all adhesives, but OptiBond FL showed cohesive failures in resin predominantly. Conclusions: The increase in the conditioning time as well as the enamel pretreatment did not provide an increase in the resin-enamel bond strength values for the studied adhesives. CLINICAL SIGNIFICANCE The surface enamel preparation and the conditioning time do not affect the performance of self-etch systems to enamel. (J Esthet Restor Dent 20:322-336, 2008)

Ultrasonic versus high-speed cavity preparation: Analysis of increases in pulpal temperature and time to complete preparation

Statement of problem. The use of ultrasonic tips has become an alternative for cavity preparation. However, there are concerns about this type of device, particularly with respect to intrapulpal temperatures and cavity preparation time.Purpose. The purpose of this study was to analyze pulpal temperature increases generated by an ultrasonic cavity preparation with chemical vapor deposition (CVD) tips, in comparison to preparation with a high-speed handpiece with a diamond rotary cutting instrument. The time required to complete the cavity preparation with each system was also evaluated.Material and methods. Thermocouples were positioned in the pulp chamber of 20 extracted human third molars. Slot-type cavities (3 x 3 x 2 mm) were prepared on the buccal and the lingual surfaces of each tooth. The test groups were: high-speed cavity preparation with diamond rotary cutting instruments (n = 20) and ultrasonic cavity preparation with CVD points (n = 20). During cavity preparation, the increases In pulpal temperature, and the time required for the preparation, were recorded and analyzed by Student's t test for paired samples (alpha = .05).Results. The average pulpal temperature increases were 4.3 degrees C for the high-speed preparation and 3.8 degrees C for the ultrasonic preparation, which were statistically similar (P = .052). However, significant differences were found (P < .001) for the time expended (3.3 minutes for the high-speed bur and 13.77 minutes for the ultrasound device).Conclusions. The intrapulpal temperatures produced during cavity preparation by ultrasonic tips versus high-speed bur preparation were similar. However, the use of the ultrasonic device required 4 times longer for the completion of a cavity preparation.

The relationship between food preparation time, time spent grocery shopping, and BMI

Recent data have shown that the percentage of time spent preparing food has decreased during the past few years, and little information is know about how much time people spend grocery shopping. Food that is pre-prepared is often higher in calories and fat compared to foods prepared at home from scratch. It has been suggested that, because of the higher energy and total fat levels, increased consumption of pre-prepared foods compared to home-cooked meals can lead to weight gain, which in turn can lead to obesity. Nevertheless, to date no study has examined this relationship. The purpose of this study is to determine (i) the association between adult body mass index (BMI) and the time spent preparing meals, and (ii) the association between adult BMI and time spent shopping for food. Data on food habits and body size were collected with a self-report survey of ethnically diverse adults between the ages of 17 and 70 at a large university. The survey was used to recruit people to participate in nutrition or appetite studies. Among other data, the survey collected demographic data (gender, race/ethnicity), minutes per week spent in preparing meals and minutes per week spent grocery shopping. Height and weight were self-reported and used to calculate BMI. The study population consisted of 689 subjects, of which 276 were male and 413 were female. The mean age was 23.5 years, with a median age of 21 years. The fraction of subjects with BMI less than 24.9 was 65%, between 25 and 29.9 was 26%, and 30 or greater was 9%. Analysis of variation was used to examine associations between food preparation time and BMI. ^ The results of the study showed that there were no significant statistical association between adult healthy weight, overweight and obesity with either food preparation time and grocery shopping time. Of those in the sample who reported preparing food, the mean food preparation time per week for the healthy weight, overweight, and obese groups were 12.8 minutes, 12.3 minutes, and 11.6 minutes respectively. Similarly, the mean weekly grocery shopping for healthy, overweight, and obese groups were 60.3 minutes per week (8.6min./day), 61.4 minutes (8.8min./day), and 57.3 minutes (8.2min./day), respectively. Since this study was conducted through a University campus, it is assumed that most of the sample was students, and a percentage might have been utilizing meal plans on campus, and thus, would have reported little meal preparation or grocery shopping time. Further research should examine the relationships between meal preparation time and time spent shopping for food in a sample that is more representative of the general public. In addition, most people spent very little time preparing food, and thus, health promotion programs for this population need to focus on strategies for preparing quick meals or eating in restaurants/cafeterias. ^

Twentieth century cook book : an up-to-date and skillful preparation on the art of cooking : and, Modern candy making simplified : also, The process of drying fruits and vegetables : and, Butchering time recipes.

Mode of access: Internet.

Tabulating equipment: card processing operations; standard time values for determining operational effectiveness for planning estimates and for budget preparation.

Mode of access: Internet.

Efficient microwave hydrothermal preparation of nanocrystalline anatase TiO2 colloids

Titanium dioxide nanocrystals are an important commercial product used primarily in white pigments and abrasives, however, more recently the anatase form of TiO2 has become a major component in electrochemical and photoelectrochemical devices. An important property of titanium dioxide nanocrystals for electrical applications is the degree of crystallinity. Numerous preparation methods exist for the production of highly crystalline TiO2 particles. The majority of these processes require long reaction times, high pressures and temperatures (450–1400 °C). Recently, hydrothermal treatment of colloidal TiO2 suspensions has been shown to produce quality crystalline products at low temperatures (<250 °C). In this paper we extend this idea utilising a direct microwave heating source. A comparison between convection and microwave hydrothermal treatment of colloidal TiO2 is presented. The resulting highly crystalline TiO2 colloids were characterised using Raman spectroscopy, XRD, TEM, and electron diffraction. The results show that the microwave treatment of colloidal TiO2 gives comparable increases in crystallinity with respect to normal hydrothermal treatments while requiring significantly less time and energy than the hydrothermal convection treatment.

Prevention of postnatal distress or depression : an evaluation of an intervention at preparation for parenthood classes.

Determined the effectiveness of a psychosocial intervention, provided to expectant couples in routine antenatal classes, on the postpartum psychosocial adjustment of women and men. Preparation for Parenthood programs were randomly allocated to one of three conditions: usual service ('control'), experimental ('empathy'), or non-specific control ('baby-play'). The latter condition controlled for the non-specific effects of the intervention, these being: the provision of an extra class; asking couples to consider the early postpartum weeks; and receiving booster information after the antenatal class, and again shortly after the birth. Women and men were categorised into three levels of self-esteem, as measured antenatally: low, medium and high. 268 participants were recruited antenatally. Interview data and self-report information was collected from 202 of these women at 6 weeks postpartum, and 180 women at 6 months postpartum. The intervention consisted of a session focusing on psychosocial issues related to becoming first-time parents. Participants discussed possible postpartum concerns in separate gender groups for part of the session, and then discussed these issues with their partners

A poly(D,L-lactide) resin for the preparation of tissue engineering scaffolds by stereolithography

Porous polylactide constructs were prepared by stereolithography, for the first time without the use of reactive diluents. Star-shaped poly(D,L-lactide) oligomers with 2, 3 and 6 arms were synthesised, end-functionalised with methacryloyl chloride and photocrosslinked in the presence of ethyl lactate as a non-reactive diluent. The molecular weights of the arms of the macromers were 0.2, 0.6, 1.1 and 5 kg/mol, allowing variation of the crosslink density of the resulting networks. Networks prepared from macromers of which the molecular weight per arm was 0.6 kg/mol or higher had good mechanical properties, similar to linear high molecular weight poly(D,L-lactide). A resin based on a 2-armed poly(D,L-lactide) macromer with a molecular weight of 0.6 kg/mol per arm (75 wt%), ethyl lactate (19 wt%), photo-initiator (6 wt%), inhibitor and dye was prepared. Using this resin, films and computer-designed porous constructs were accurately fabricated by stereolithography. Pre-osteoblasts showed good adherence to these photocrosslinked networks. The proliferation rate on these materials was comparable to that on high molecular weight poly(D,L-lactide) and tissue culture polystyrene.

Provisional supervision in Hong Kong : third time lucky?

Provisional supervision (PS) is Hong Kong’s proposed new corporate rescue procedure. In essence, it is a procedure for the preparation by a professional, usually an accountant or a solicitor, of a proposal for a voluntary arrangement, supported by a moratorium. There should be little court involvement in the process and it is anticipated that the costs and delays of the process would be less than alternate, currently available procedures. This article will retrace some of the key events and issues arising from the numerous policy and legislative debates about PS in Hong Kong. At present the Hong Kong government is in the midst of drafting a new Bill on corporate rescue procedure to be introduced to the HKSAR Legislative Council. This will be the third attempt. Setting aside the controversies and the content of this new effort by the Hong Kong administration, the Global Financial Crisis in 2008 has signalled to the international policy and business community, free markets alone cannot be an effective regulatory mechanism. Having legal safeguards and clear rules to regulate procedures and conduct of market participants are imperative to avoid future financial meltdowns.