Propriedades elétricas e magnéticas de novos compostos com o ânion condutor [Ni(dmit)2]- e radicais magnéticos nitronil nitróxido

Three compounds have been synthesized with formulae [3-MeRad][Ni(dmit)2] (1), [4-MeRad][Ni(dmit)2] (2) and [4-PrRad][Ni(dmit)2] (3) where [Ni(dmit)2]- is an anionic pi-radical (dmit = 1,3-dithiol-2-thione-4,5-dithiolate) and [3-MeRad]+ is 3-N-methylpyridinium alpha-nitronyl nitroxide, [4-MeRad]+ is 4-N-methylpyridinium alpha-nitronyl nitroxide and [4-PrRad]+ is 4-N-propylpyridinium alpha-nitronyl nitroxide. The temperature-dependent magnetic susceptibility of 1 revealed that an antiferromagnetic interaction operates between the 3-MeRad+ radical cations with exchange coupling constants of J1 = - 1.72 cm-1 and antiferromagnetism assigned to the spin ladder chains of the Ni(dmit)2 radical anions. Compound 1 exhibits semiconducting behavior and 3 presents capacitor behavior in the temperature range studied (4 - 300 K).

EXPERIMENTAL INFECTION WITH Toxocara cati IN PIGS: MIGRATORY PATTERN AND PATHOLOGICAL RESPONSE IN EARLY PHASE

Experimental inoculations of approximately 100,000 infective Toxocara cati larval eggs were done in twelve pigs. The T. cati eggs used for inoculation were collected from cat's feces. Another group of three pigs served as an uninfected control. Groups of infected pigs were euthanized at seven, 14, 21, and 28 days post-inoculation (dpi). Tissue samples were taken for digestion and histopathology changes in early phase. The number of larvae recovered from the lungs peaked at seven and 14 dpi and were also present at 21, and 28 dpi. Larvae of T. cati were present in the lymph nodes of the small and large intestine at seven, 14, and 28 dpi and at seven, 14, 21, and 28 dpi respectively. In other studied tissues, no larvae or less than one larva per gram was detected. The pathological response observed in the liver and lungs at seven and 14 dpi, showed white spots on the liver surface and areas of consolidation were observed in the lungs. The lungs showed an inflammatory reaction with larvae in center at 28 dpi. In the liver we observed periportal and perilobular hepatitis. The lymph nodes of the intestines displayed eosinophil lymphadenitis with reactive centers containing parasitic forms in some of them. The granulomatous reaction was not observed in any tissues. The role of the other examined tissues had less significance. The relevance of this parasite as an etiological agent that leads to disease in paratenic hosts is evident.

Estudo necroscópico de um caso da forma crônica da doença de Chagas com eletrocardiograma e raio-X de tórax normais: referência especial ao sistema excito-condutor do coração

Descrevem-se as alterações anatomopatológicas observadas na necropsia de chagásico crônico, provavelmente, portador da forma indeterminada da doença. O coração mostrou lesões dos três folhetos e do sistema excito-condutor, traduzidas especialmente por pequenos focos inflamatórios. Havia discreta fibrose do miocárdio contrâtil, nódulo átrio-ventricular e origem do ramo esquerdo do feixe de His. Tais alterações, embora de leve intensidade, assemelham-se, qualitativamente, às relatadas nas demais formas crônicas da doença de Chagas e representam lesões ativas, com potencial evolutivo. No esôfago, observou-se entre outros fatos, despopulação neuronal acentuada.

Cardiopatia chagásica crônica causando insuficiência cardíaca congestiva na infância: estudo clínico e histopatológico de um caso, com ênfase para as lesões dos sistemas excito-condutor e nervoso autônomo intracardíaco

Descreve-se caso de cardiopatia chagásica em menino de nove anos, natural e procedente do sulde Goiás, que desenvolveu insuficiência cardíaca congestiva quatro meses antes do óbito. As reações sorológicaspara doença de Chagas eram reagentes, epositivo o xenodiagnóstico. Os eletrocardiogramas mostraram taquicardia sinusal, extra-sístoles ventriculares e supraventriculares, hemibloqueio anterior esquerdo, bloqueio completo do ramo direito e sinais de sobrecarga de câmaras. O exame ecocardiográfico evidenciou dilatação de câmaras com hipocontratilidade difusa. O quadro se agravou progressivamente, complicando-se por vários episódios pneumônicos, o último dos quais provocou o óbito. A necrópsia, verificou-se, no coração, inflama ção crônica dos três folhetos, com miocardite crônica fibrosante predominando no septo interventricular e no ventrículo esquerdo. As estruturas componentes do sistema excito-condutor mostraram processoflogístico crônico, essencialmente exsudativo, ora discreto, ora moderado. No sistema nervoso autônomo intracardíaco constataram-se focos esparsos de discreta periganglionite crônica, e raros fenômenos degenerativos dos neurônios sem despopulação neuronal.

Contribuição ao conhecimento da cardiopatia chagásica aguda: estudo sistematizado dos sistemas excito-condutor e nervoso autônomo intracardíaco em caso autóctone do Acre

Descrevem-se as alterações anatomopatológicas do coração obseivadas em um caso agudo de doença de Chagas (DC), com ênfase para as lesões do sistema excito-condutor (SEC) e do sistema newoso autônomo intracardíaco (SNAIC). O exame microscópico, evidenciou pancardite aguda, com numerosas formas amastigotas de Trypanosoma cruzi em miocardiócitos. Constataram-se múltiplos focos inflamatórios no SEC, com ninhos parasitários no nódulo átrio-ventricular e no ramo esquerdo do feixe de His. Na análise das estruturas autonômicas atriais, verificaram-seperiganglionite eperineurite acentuadas, com ou sem infiltração periférica de gânglios e newos pelo exsudato. Não pareceu ocorrer despopulação neuronal cardíaca. O estudo epidemiológico sugeriu transmissão vetorial por Rhodnius pictipes. Este ê o primeiro caso de DC aguda da região amazônica em que se faz a avaliação morfológica sistematizada e concomitante do SEC e do SNAIC.

Estudos eletrofisiológicos seriados do sistema éxcito-condutor do coração de pacientes com cardiopatia chagásica crônica

OBJETIVOS:Estudar a evolução das lesões do sistema de condução do coração, por meio de estudos eletrofisiológicos (EEF) invasivos, o impacto dessas alterações nos eventos cardiovasculares (ECV) e a freqüência desses eventos em pacientes com cardiopatia chagásica crônica. MÉTODOS: Estudo prospectivo iniciado em 1979, com seguimento clínico até 2000, com participação de 28 pacientes chagásicos crônicos, com idade entre 18 e 65 anos, portadores de bloqueios de ramo e/ou bloqueios atrioventriculares (AV). Os pacientes foram submetidos a dois EEF, com intervalo de tempo mínimo de 4 anos, sendo estudados 5 parâmetros eletrofisiológicos, que foram correlacionados com ECV. Holter de 24 horas e ecocardiograma foram realizados. RESULTADOS: O tempo médio de seguimento após o 1º EEF foi de 154,5 meses, enquanto o intervalo entre os EEF foi de 107,5 meses. A idade variou entre 25 e 65 anos. Vinte e sete pacientes apresentavam bloqueio completo de ramo direito, associado ou não a bloqueio divisional ântero-superior esquerdo. O ecocardiograma foi alterado em 12 pacientes. Ao Holter de 24 horas e à estimulação ventricular, apenas um paciente apresentou TVS. Nove apresentaram ECV e somente o intervalo HV >70 ms apresentou relação estatisticamente significante com esses eventos. CONCLUSÕES: a) A forma crônica da doença de Chagas apresenta diferentes porcentagens de anormalidades evolutivas nas variáveis eletrofisiológicas, sendo a mais freqüente a alteração no PW. b) Entre os achados eletrofisiológicos, somente o intervalo HV > 70 ms relacionou-se com ECV. c) A incidência de ECV foi de 31,1% seguimento médio de 154,5 meses.

Larval recovery of Toxocara cati in experimentally infected Rattus norvegicus and analysis of the rat as potential reservoir for this ascarid

Toxocara cati is a common feline parasite transmitted by the ingestion of embryonated eggs, by the transmammary route or by predation of paratenic hosts harbouring third-stage larvae in their bodies. In the present study, the larval distribution of T. cati in tissues and organs of Rattus norvegicus experimentally infected with 300 embryonated eggs was analysed. Third-stage larvae were recovered from livers, lungs, kidneys, eyes, brains and carcasses of infected rats, following tissue digestion with HCl 0.5% for 24 h at 37°C. Some differences from the known larval distribution of Toxocara canisin the same rodent species were found.

Does Interviewer-Respondent Socio-Demographic Matching Increase Cooperation in Centralized CATI Household Panels?

Overall it seems that age and gender interviewer characteristics are relevant in achieving higher cooperation rates by telephone panel members. This appears to be the case especially for older male interviewers, who perform the best on gaining cooperation across different types of respondents. This holds if important interviewer covariates like experience are controlled for. There is no evidence that special sex age or sex matches yield a higher cooperation. It may be that not only the perceived authority of the institution that sponsors the survey plays a role when it comes to cooperation (Groves et al., 1992) but also of the interviewer who asks for this cooperation. Presumably older men have more authority to convince sample members to participate. A simple recommendation is to use as many older male interviewers as possible for the recruitment phase. It is likely that this strategy would also be successful in other western cultures than Switzerland.

Cooperation in centralised CATI Household Panel Surveys : A Contact-based Multilevel Analysis to Examine Interviewer, Respondent, and Fieldwork Process Effects

In this research, we analyse the contact-specific mean of the final cooperation probability, distinguishing on the one hand between contacts with household reference persons and with other eligible household members, and on the other hand between first and later contacts. Data comes from two Swiss Household Panel surveys. The interviewer-specific variance is higher for first contacts, especially in the case of the reference person. For later contacts with the reference person, the contact-specific variance dominates. This means that interaction effects and situational factors are decisive. The contact number has negative effects on the performance of contacts with the reference person, positive in the case of other persons. Also time elapsed since the previous contact has negative effects in the case of reference persons. The result of the previous contact has strong effects, especially in the case of the reference person. These findings call for a quick completion of the household grid questionnaire, assigning the best interviewers to conducting the first contact. While obtaining refusals has negative effects, obtaining other contact results has only weak effects on the interviewer's subsequent contact outcome. Using the same interviewer for contacts has no positive effects.

A Note on Interviewer Performance Measures in centralised CATI Surveys

Interviewer performance with respect to convincing sample members to participate in surveys is an important dimension of survey quality. However, unlike in CAPI surveys where each sample case 'belongs' to one interviewer, there are hardly any good measures of interview performance for centralised CATI surveys, where even single contacts are assigned to interviewers at random. If more than one interviewer works one sample case, it is not clear how to attribute success or failure to the interviewers involved. In this article, we propose two correlated methods to measure interviewer contact performance in centralised CATI surveys. Their modelling must take complex multilevel clustering effects, which need not be hierarchical, into account. Results are consistent with findings from CAPI data modelling, and we find that when comparing effects with a direct ('naive') measure of interviewer contact results, interviewer random effects are largely underestimated using the naive measure.

Interviewer and Respondent Survey Quality Effects in a CATI Panel

Especially in panel surveys, respondent attrition, respondent learning, and interviewer experience effects play a crucial role with respect to data quality. We examine three interview survey quality indicators in the same survey in a cross sectional as well as in a longitudinal way. In the cross sectional analysis we compare data quality in the mature original sample with that in a refreshment sample, surveyed in the same wave. Because in the same wave an interviewer survey was conducted, collecting attitudes on their socio demography, survey attitudes and burden measures, we are able to consider interviewer fixed effects as well. The longitudinal analysis gives more insight in the respondent learning effects with respect to the quality indicators considered by considering the very same respondents across waves. The Swiss Household Panel, a CATI survey representative of the Swiss residential population, forms an ideal modelling database: the interviewer - respondent assignment is random, both within and across waves. This design avoids possible confusion with other effects stemming from a non-random assignment of interviewers, e.g. area effects or effects from assigning the best interviewers to the hard cases. In order to separate interviewer, respondent and wave effects, we build cross-classified multilevel models.

Modificação do polímero condutor polianilina para uso como trocador catiônico

This article reports the use of polyaniline (PAni), chemically and electrochemically synthesized, for copper removal from aqueous solutions. PAni films were electrodeposited on reticulated vitreous carbon (RVC). In all cases, p-toluenesulfonate anion (PTS-) was used as the dopant to obtain cation exchange properties. RVC/PAni showed no expressive copper removal due to the small amount of polymer in the film. Chemically synthesized PAni-PTS- was obtained in its reduced form (leucoesmeraldine). PAni degraded at neutral pH but remained stable at low pH, showing a very high ion-exchange capacity, which is superior to those observed for commercial resins.