Time- and concentration-dependent cytotoxicity of antibiotics used in endodontic therapy

OBJECTIVE: New drugs have to be assessed in endodontic therapy due to the presence of microorganisms resistant to therapeutic procedures. Thus, this study evaluated the time- and concentration-dependent cytotoxicity of different antibiotics used in endodontic therapy. MATERIAL AND METHODS: Human gingival fibroblasts were treated and divided into the following experimental groups: Group I - control; Group II - ciprofoxacin hydrochloride; Group III - clyndamicin hydrochloride; and Group IV - metronidazole. Each drug was used at concentrations of 5, 50, 150, and 300 mg/L for 24, 48, 72, and 96 h. Cytotoxicity was evaluated by the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and spectrophotometric reading of ELISA plates. The results were analyzed by BioEstat 4.0 software using Kruskal-Wallis and Dunn's tests at a signifcance level of 5%. Cell viability was assessed for the different concentrations and times. RESULTS: All drugs presented dose-dependent cytotoxicity. Concentrations of 5 and 50 mgjL produced viable fibroblasts at all experimental times in all groups. CONCLUSIONS: Cell viability at 24 h was greater than in the other experimental times. Comparison between the same concentrations of antibiotics at different times showed that metronidazole presented the highest cell viability at 72 and 96 h compared to the other antibiotics, whereas clyndamicin hydrochloride showed higher cell viability at 72 h than ciprofoxacin hydrochloride.

Time trends and predictors of mortality from ill-defined causes in old age: 9 year folllow-up of the Bambuí cohort study (Brazil)

The study objective was to examine differentials in time trends and predictors of deaths assigned to symptoms, signs and ill-defined conditions in comparison with other ill-defined conditions (ill-defined cardiovascular diseases, cancer and injury) in a population-based cohort study. Of 1,606 baseline participants aged 60 years and over, 524 died during 9-year follow-up and were included in this study. Deaths coded to "symptoms" declined by 77% in the period from 1997-1999 to 2003-2005. Deaths coded to other ill-defined conditions remained unchanged. The calendar period 2003-2005 (RR = 0.25; 95%CI: 0.09-0.70) and in-hospital deaths (RR = 0.16; 95%CI: 0.08-0.34) were independently associated with "symptoms", but not with other ill-defined conditions. Baseline socio-demographic characteristics and chronic diseases were not predictors of these outcomes. International and national agencies have focused on the reduction of deaths assigned to "symptoms" to improve the registration of vital statistics, while other ill-defined conditions have received little attention. Our data provide evidence supporting the need to redress this situation.

O sexo sem lei, o poder sem rei: sexualidade, gênero e identidade no cotidiano travesti

Neste trabalho propomos questionar como são construídos e validados os discursos acerca de sexualidade, gênero e identidade sexual, a partir da história de vida de três irmãos homossexuais nascidos no interior do nordeste brasileiro. Ainda jovens, migraram para a cidade de Diadema - São Paulo, onde se tornaram, no decorrer de alguns anos, travestis e profissionais do sexo. A percepção da homossexualidade foi relatada como parte da infância, e sentida como uma força natural. Já, as transformações realizadas sobre o corpo decorrentes da travestilidade, a decisão pela prostituição, a orientação sexual (por homem ou por mulher), e a construção de uma identidade sexual (gay ou travesti), apareceram como instâncias dissociadas entre si e relacionadas à busca da valorização pessoal e social diante do estigma atribuído ao gay afeminado, pobre e migrante. A religiosidade afro-brasileira e a gramática yorubá assumiram relevância para a constituição desta possibilidade identitária.

Acidentes de trânsito causando vítimas: possível reflexo da lei seca nas internações hospitalares

Os acidentes de trânsito no Brasil se constituem em relevante problema para a área da saúde. Nesse sentido, julgou-se importante investigar qual o efeito da lei 11.705 de 19 de junho de 2008, a chamada Lei seca. A metodologia do trabalho constitui analisar os dados do Sistema de Informações Hospitalares do SUS, para o Brasil, em 2008, comparando as internações nos dois semestres do ano, segundo algumas variáveis consideradas importantes. Os resultados mostraram que houve uma queda de 28,3 por cento nas internações do segundo semestre, com reflexos consideráveis em todas as variáveis estudadas. Quanto à qualidade da vítima, a maior queda ocorreu entre os ocupantes de automóvel, principalmente do sexo masculino. Em relação às idades, houve declínio em todas as faixas, destacando-se as de 40 a 59 anos e 20 a 39 anos, pela ordem. O tempo de permanência na instituição foi menor no segundo semestre,quando a mortalidade hospitalar declinou 13,6 por cento em relação ao primeiro semestre, o que significa que deixaram de morrer 917 pessoas (cerca de 5 mortes/dias). O gasto governamental para o atendimento dos feridos no segundo semestre foi 35,5 por cento menor do que no primeiro

Internal and external time conflicts in adolescents: sleep characteristics and interventions

Daytime fatigue and lack of sleep seem to increase throughout adolescent years. Several environmental, psychological, and biological factors have been associated with the development of sleep across adolescence. The aim of the present article is to summarize these factors and to give examples of various outcomes in sleep patterns among adolescents studied in different cultural settings. It is obvious from earlier work that many adolescents have displaced circadian rhythms and lack of adaptation to school hours due to an early school start or additional burdens for work. Several interventions have aimed to help the adaptation process by supporting sleep processes and changing scheduling, in this way promoting classroom alertness. In summary, adolescents worldwide shorten their sleep due to schoolwork hours and additional work, especially by disturbing their sleep due to circadian misalignment

Work start time and chronotype of indoor and outdoor daytime workers

Introdução e objetivo: A exposição à luz natural tem efeitos relevantes no sistema de temporização biológica. Pode-se supor que essa exposição poderia promover um ajuste melhor entre os ritmos biológicos e os horários de início de trabalho entre trabalhadores diurnos de ambientes externos. O objetivo deste estudo foi comparar a matutinidade/vespertinidade e a relação entre o horário de trabalho real e o ideal em trabalhadores diurnos expostos a condições de iluminação distintas. Métodos: O estudo foi conduzido com dois grupos de trabalhadores (n=49) que residiam em uma área rural e tinham condições sociais similares. Um grupo trabalhava em ambiente interno (n=20, idade média 30,8 anos (21-50); desvio padrão=9,8) e o outro grupo trabalhava em ambiente externo (n=29, idade média 30,8 anos (17- 50); desvio padrão=10,0). Os trabalhadores preencheram um questionário de matutinidade/vespertinidade (MEQ). Foi realizada uma ANOVA de um fator com o intuito de comparar os escores do MEQ entre os dois grupos de trabalhadores. Resultados: Como esperado, o Grupo do Ambiente Externo (GAE) apresentou média de escores mais elevada que o Grupo do Ambiente Interno (GAI), o que significa uma tendência à matutinidade (GAE: 58,4±7,9; GAI; 47,4±6,4), com significância estatística (F=26,22; p<0,001). De acordo com os dados relatados em relação aos horários de trabalho, o GAE gostaria de atrasar seu horário de trabalho em 31 minutos, em média, enquanto que o GAI gostaria de atrasar em 96 minutos seu horário de trabalho (F=7,71; p<0,01). Conclusões: Os resultados desse estudo sugerem que a exposição à luz natural pode promover um ajuste melhor aos horários de início de trabalho matutinos

A construção do direito à saúde no Brasil

O direito à saúde recebeu - pela primeira vez - tratamento constitucional no brasil em 1988, fruto de grande participação popular. Neste estudo, se busca compreender a extensão dessa afirmação e verificar sua implementação normativa e jurisprudencial. A partir do estudo da evolução dos conceitos de saúde e de direito, concluiu-se que o direito à saúde deve implicar a constante participação popular para que possa ser delimitado. Verificou-se, também, que o arcabouço normativo vem sendo construído em conformidade com as exigências constitucionais. Quanto à construção jurisprudencial, se percebeu que ela vem acontecendo de forma errática e que os tribunais superiores raramente enfrentam a discussão da política de saúde desenhada na Constituição da República Federativa do Brasil de 1988. Concluiu-se que a afirmação constitucional tem demonstrado vigor, haja vista o grande desenvolvimento normativo conforme `compreensão contemporânea; e que o controle judicial da realização da política sanitária é ainda incipiente

Exact time-dependent solutions for a self-regulating gene

The exact time-dependent solution for the stochastic equations governing the behavior of a binary self-regulating gene is presented. Using the generating function technique to rephrase the master equations in terms of partial differential equations, we show that the model is totally integrable and the analytical solutions are the celebrated confluent Heun functions. Self-regulation plays a major role in the control of gene expression, and it is remarkable that such a microscopic model is completely integrable in terms of well-known complex functions.

Do synergies improve accuracy? A study of speed-accuracy trade-offs during finger force production

We explored possible effects of negative covariation among finger forces in multifinger accurate force production tasks on the classical Fitts's speed-accuracy trade-off. Healthy subjects performed cyclic force changes between pairs of targets ""as quickly and accurately as possible."" Tasks with two force amplitudes and six ratics of force amplitude to target size were performed by each of the four fingers of the right hand and four finger combinations. There was a close to linear relation between movement time and the log-transformed ratio of target amplitude to target size across all finger combinations. There was a close to linear relation between standard deviation of force amplitude and movement time. There were no differences between the performance of either of the two ""radial"" fingers (index and middle) and the multifinger tasks. The ""ulnar"" fingers (little and ring) showed higher indices of variability and longer movement times as compared with both ""radial"" fingers and multifinger combinations. We conclude that potential effects of the negative covariation and also of the task-sharing across a set of fingers are counterbalanced by an increase in individual finger force variability in multifinger tasks as compared with single-finger tasks. The results speak in favor of a feed-forward model of multifinger synergies. They corroborate a hypothesis that multifinger synergies are created not to improve overall accuracy, but to allow the system larger flexibility, for example to deal with unexpected perturbations and concomitant tasks.

Time-frequency and time-scale analysis of Barkhausen noise signals

Carrying out information about the microstructure and stress behaviour of ferromagnetic steels, magnetic Barkhausen noise (MBN) has been used as a basis for effective non-destructive testing methods, opening new areas in industrial applications. One of the factors that determines the quality and reliability of the MBN analysis is the way information is extracted from the signal. Commonly, simple scalar parameters are used to characterize the information content, such as amplitude maxima and signal root mean square. This paper presents a new approach based on the time-frequency analysis. The experimental test case relates the use of MBN signals to characterize hardness gradients in a AISI4140 steel. To that purpose different time-frequency (TFR) and time-scale (TSR) representations such as the spectrogram, the Wigner-Ville distribution, the Capongram, the ARgram obtained from an AutoRegressive model, the scalogram, and the Mellingram obtained from a Mellin transform are assessed. It is shown that, due to nonstationary characteristics of the MBN, TFRs can provide a rich and new panorama of these signals. Extraction techniques of some time-frequency parameters are used to allow a diagnostic process. Comparison with results obtained by the classical method highlights the improvement on the diagnosis provided by the method proposed.

The Effect of Spatial Scale on Predicting Time Series: A Study on Epidemiological System Identification

A susceptible-infective-recovered (SIR) epidemiological model based on probabilistic cellular automaton (PCA) is employed for simulating the temporal evolution of the registered cases of chickenpox in Arizona, USA, between 1994 and 2004. At each time step, every individual is in one of the states S, I, or R. The parameters of this model are the probabilities of each individual (each cell forming the PCA lattice ) passing from a state to another state. Here, the values of these probabilities are identified by using a genetic algorithm. If nonrealistic values are allowed to the parameters, the predictions present better agreement with the historical series than if they are forced to present realistic values. A discussion about how the size of the PCA lattice affects the quality of the model predictions is presented. Copyright (C) 2009 L. H. A. Monteiro et al.

Synchronization of Discrete-Time Chaotic Systems in Bandlimited Channels

Over the last couple of decades, many methods for synchronizing chaotic systems have been proposed with communications applications in view. Yet their performance has proved disappointing in face of the nonideal character of usual channels linking transmitter and receiver, that is, due to both noise and signal propagation distortion. Here we consider a discrete-time master-slave system that synchronizes despite channel bandwidth limitations and an allied communication system. Synchronization is achieved introducing a digital filter that limits the spectral content of the feedback loop responsible for producing the transmitted signal. Copyright (C) 2009 Marcio Eisencraft et al.

Validation of reference genes for gene expression studies in the honey bee, Apis mellifera, by quantitative real-time RT-PCR

For obtaining accurate and reliable gene expression results it is essential that quantitative real-time RT-PCR (qRT-PCR) data are normalized with appropriate reference genes. The current exponential increase in postgenomic studies on the honey bee, Apis mellifera, makes the standardization of qRT-PCR results an important task for ongoing community efforts. For this aim we selected four candidate reference genes (actin, ribosomal protein 49, elongation factor 1-alpha, tbp-association factor) and used three software-based approaches (geNorm, BestKeeper and NormFinder) to evaluate the suitability of these genes as endogenous controls. Their expression was examined during honey bee development, in different tissues, and after juvenile hormone exposure. Furthermore, the importance of choosing an appropriate reference gene was investigated for two developmentally regulated target genes. The results led us to consider all four candidate genes as suitable genes for normalization in A. mellifera. However, each condition evaluated in this study revealed a specific set of genes as the most appropriated ones.

Time Changes with the Embodiment of Another's Body Posture

The aim of the present study was to investigate whether the perception of presentation durations of pictures of different body postures was distorted as function of the embodied movement that originally produced these postures. Participants were presented with two pictures, one with a low-arousal body posture judged to require no movement and the other with a high-arousal body posture judged to require considerable movement. In a temporal bisection task with two ranges of standard durations (0.4/1.6 s and 2/8 s), the participants had to judge whether the presentation duration of each of the pictures was more similar to the short or to the long standard duration. The results showed that the duration was judged longer for the posture requiring more movement than for the posture requiring less movement. However the magnitude of this overestimation was relatively greater for the range of short durations than for that of longer durations. Further analyses suggest that this lengthening effect was mediated by an arousal effect of limited duration on the speed of the internal clock system.