The Stability and Properties of Polystyrene/Kaolinite Nanocomposites during Synthesis via Emulsion Polymerization.

The aim of this work was to study the stability and morphological properties of polystyrene latex containing kaolinite as a filler during the process of synthesis of nanocomposites viaemulsion polymerization. Nanocomposites with 1, 3, and 5 wt% of kaolinite were prepared. Latexes with 1 to 3 wt% of kaolinite were stable during the polymerization reaction. Hydrodynamic diameters of 93.68 and 82.11 nm were found for latexes with 1 and 3 wt% of kaolinite, respectively. The quantities of 1 to 3 wt% of kaolinite added during the reaction did not influence the reaction conversion curves or the number of particles. X-ray diffraction (XRD) and unconventional techniques of scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) showed the presence of exfoliated and intercalated structures of the kaolinite.

Singlet oxygen production by pyrano and furano 1,4-naphthoquinones in non-aqueous medium.

The influence of ring size on the photobehaviour of condensed 1,4-naphthoquinone systems, such as pyrano- and furano-derivatives (1 and 2, respectively) has been investigated. The absorption spectra for both families of naphthoquinones reveal clear differences; in the case of 2 they extend to longer wavelengths. A solvatochromic red shift in polar solvents is consistent with the π,π* character of the S(0)→ S(1) electronic transition in all cases. Theoretical (B3LYP) analysis of the HOMO and LUMO Kohn-Sham molecular orbitals of the S(0) state indicates that they are π and π* in nature, consistent with the experimental observation. A systematic study on the efficiency of singlet oxygen generation by these 1,4-naphthoquinones is presented, and values larger than 0.7 were found in every case. In accordance with these results, laser flash photolysis of deoxygenated acetonitrile solutions led to the formation of detectable triplet transient species with absorptions at 390 and 450 nm (1) and at 370 nm (2), with φ(ISC) close to 1. Additionally, the calculated energies for the T(1) states relative to the S(0) states at UB3LYP/6-311++G** are ca. 47 kcal mol(-1) for 1 and 43 kcal mol(-1) for 2. A comparison of the geometrical parameters for the S(0) and T(1) states reveals a marked difference with respect to the arrangement of the exocyclic phenyl ring whilst a comparison of electronic parameters revealed the change from a quinone structure to a di-dehydroquinone diradical structure.

[Conjoined twins: an experience of a tertiary hospital in Southeast Brazil]. / Gêmeos conjugados: experiência de um hospital terciário do sudeste do Brasil.

PURPOSE: to analyze the occurrence of conjoined twins at a tertiary perinatology reference university hospital over a period of 25 years (January 1982 to January 2007) and to describe the successful separation of one of the pairs. METHODS: we consulted retrospectively the database of the University Hospital of the Medical School of Ribeirão Preto, University of São Paulo, Brazil, in order to determine the number of pairs of conjoined twins, their frequency, classification, gender, type of pregnancy resolution, attempted surgical separation, prenatal diagnosis and survival. RESULTS: we detected 14 pairs of conjoined twins (1/22,284 live births and 1/90 pairs of twin live births) born during this period (six males, seven females and one of indeterminate sex). The prenatal diagnosis was performed in all twins and all births were accomplished by cesarean section. The separation was possible in only one pair, which survives in excellent health conditions after eight years. Of the remaining 13, ten died on the day of birth and three survived only a few months (less than one year). CONCLUSION: Although our study revealed an abnormally high number of conjoined twins, this is a rare phenomenon, with a poor perinatal prognosis depending on the organs shared by the twins and associated malformations, especially those related to the fetal heart. Due to the poor prognosis of these pairs and to the maternal reproductive impairment caused by the need to perform body cesareans, we suggest that, based on these numbers, early interruption of these pregnancies be legally granted, as in the case of other diseases incompatible with fetal survival outside the uterus. Thus, the confirmation of a diagnosis of conjoined twins and the resolution of pregnancy should be performed at a tertiary obstetric and perinatal care center, and an authorization for the interruption of pregnancy should be obtained by judicial means.

Gêmeos conjugados: experiência de um hospital terciário do sudeste do Brasil / Conjoined twins: an experience of a tertiary hospital in Southeast Brazil

OBJETIVO: analisar a ocorrência de gemelaridade conjugada em um hospital universitário de referência terciária em perinatologia durante 25 anos (janeiro de 1982 e janeiro de 2007) e descrever a separação bem sucedida de um dos pares. MÉTODOS: para este fim, utilizamos retrospectivamente o banco de dados do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, obtendo o número de pares de gêmeos conjugados, sua frequência, classificação, gênero, forma de resolução da gravidez, tentativa de separação cirúrgica, diagnóstico pré-natal e sobrevida. RESULTADOS: detectamos 14 pares de gêmeos conjugados (1/22.284 nascidos vivos e 1/90 pares de gêmeos nascidos vivos) nascidos neste período (seis masculinos, sete femininos e um com sexo indeterminado). O diagnóstico pré-natal foi realizado em todos os gêmeos, e os nascimentos ocorreram por cesariana. A separação só foi possível em um dos pares, que sobrevivem em ótimas condições de saúde após oito anos. Dos 13 restantes, dez morreram no mesmo dia do nascimento e três sobreviveram apenas alguns meses (menos de um ano). CONCLUSÃO: apesar de este estudo evidenciar um número anormalmente alto de gêmeos conjugados, trata-se de um fenômeno raro, de prognóstico perinatal reservado e dependente do compartilhamento de órgãos entre os gêmeos e malformações associadas, em especial relacionadas ao coração dos fetos. Devido ao mau prognóstico dos pares e do comprometimento reprodutivo materno pela necessidade de realização de cesariana com grandes incisões uterinas, propomos que, com base nestes números, seja solicitada a interrupção precoce destas gestações, como ocorre com outras doenças fetais incompatíveis com a sobrevida extrauterina. Desta forma, a confirmação diagnóstica e a resolução da gravidez de gêmeos conjugados deve ser realizada em centro de atendimento terciário tanto obstétrico quanto perinatal, e a autorização para a interrupção da gestação obtida por via judicial.

PURPOSE: to analyze the occurrence of conjoined twins at a tertiary perinatology reference university hospital over a period of 25 years (January 1982 to January 2007) and to describe the successful separation of one of the pairs. METHODS: we consulted retrospectively the database of the University Hospital of the Medical School of Ribeirão Preto, University of São Paulo, Brazil, in order to determine the number of pairs of conjoined twins, their frequency, classification, gender, type of pregnancy resolution, attempted surgical separation, prenatal diagnosis and survival. RESULTS: we detected 14 pairs of conjoined twins (1/22,284 live births and 1/90 pairs of twin live births) born during this period (six males, seven females and one of indeterminate sex). The prenatal diagnosis was performed in all twins and all births were accomplished by cesarean section. The separation was possible in only one pair, which survives in excellent health conditions after eight years. Of the remaining 13, ten died on the day of birth and three survived only a few months (less than one year). CONCLUSION: Although our study revealed an abnormally high number of conjoined twins, this is a rare phenomenon, with a poor perinatal prognosis depending on the organs shared by the twins and associated malformations, especially those related to the fetal heart. Due to the poor prognosis of these pairs and to the maternal reproductive impairment caused by the need to perform body cesareans, we suggest that, based on these numbers, early interruption of these pregnancies be legally granted, as in the case of other diseases incompatible with fetal survival outside the uterus. Thus, the confirmation of a diagnosis of conjoined twins and the resolution of pregnancy should be performed at a tertiary obstetric and perinatal care center, and an authorization for the interruption of pregnancy should be obtained by judicial means.

Resultados perinatais e maternos de gestantes adolescentes / Perinatal and maternal results of adolescent pregnant girls

Objetivo: Análise retrospectiva dos achados clínicos de gestantes adolescentes e adultas (grupo-controle) atendidas em um centro de atendimento terciário em Ribeirão Preto, no período de um ano. Métodos: Foram analisados os prontuários médicos de 438 pacientes de um centro de atendimento terciário em Ribeirão Preto, sendo que a população estudada foi dividida em Grupos I, II e III, segundo a faixa etária materna: 10 a 14, 15 a 19 e 20 a 35 anos, respectivamente. As variáveis analisadas foram: idade materna no parto, tipo de parto, patologias maternas, duração da gestação, peso ao nascer e índice de Apgar. A análise estatística foi realizada para variáveis qualitativas por meio do teste X2 e para variáveis quantitativas por meio dos testes ?t de Student? e análise de variância para medidas repetidas. Resultados: Analisando-se o total dos partos nos dois hospitais, a taxa de cesariana foi maior nos grupos I (28,9%) e II (37%) em relação ao grupo III (19,5%) (p=0,0008). Evidenciamos uma maior incidência de trabalho de parto pré-termo no grupo I (57,1%) em relação ao grupo III (26%) (p=0,022). O peso fetal ao nascer foi significantemente mais baixo entre pacientes do grupo I (23,1%) em relação ao grupo III (5,5%) (p=0,002). Conclusão: O presente estudo demonstrou que a gestação na adolescência se associou a maior freqüência de parto pré-termo, baixo peso ao nascer e parto cesárea desta forma se justificam estudos que visem reduzir as complicações maternas e perinatais.

Hormonal assessment of women submitted to tubal ligation.

Sixteen fertile women aged 30-35 years with regular menstruations were studied before and 6 months after tubal ligation (TL). The diagnosis of ovulation was based on clinical ultrasonographic and hormonal parameters [follicle-stimulating hormone (FSH), luteinizing hormone (LH), E2 and P4]. The menstrual pattern did not vary before and after surgery. Follicular or luteal phase FSH and E2 levels did not differ between the pre- and post-TL period. Luteinizing hormone levels on days -2 and 0 of the follicular phase were significantly higher during the post-TL period, while no difference was observed for the luteal phase. P4 levels during the follicular phase did not differ between the two periods, except for day -4, while they were lower during the post-TL luteal phase. The results of the study suggest that in the present patient group, no modifications in the menstrual pattern could be observed 6 months after TL, and TL appears not to interfere with ovulation. Luteinizing hormone levels showed an increase during the ovulatory period after TL, and progesterone secretion decreased during the post-TL luteal phase.

Thin-section CT abnormalities and pulmonary gas exchange impairment in workers exposed to asbestos.

PURPOSE: To evaluate the relationship between abnormalities at thin-section computed tomography (CT) and indexes of pulmonary gas exchange impairment at rest and during moderate exercise in workers exposed to asbestos. MATERIALS AND METHODS: Eighty-two workers with long-term exposure to asbestos and abnormal thin-section CT findings underwent respiratory physiologic measurements at rest (lung diffusing capacity, Dlco) and during exercise (oxygen uptake-corrected alveolar-arterial pressure difference for oxygen, DeltaP[A-a]O(2)/VO(2)). CT results were compared with physiologic measurements of impairment in gas exchange (Dlco < 70% predicted value and/or DeltaP[A-a]O(2)/VO(2) > 20 mm Hg. L. min(-1)). The CT findings were divided into five categories by using a previously described method. Odds ratios and 95% CIs for gas exchange defects were calculated for patients grouped according to CT findings. Logistic regression analysis was performed with gas exchange as the dependent response and CT abnormalities as independent variables. RESULTS: A significant association was found between extent of disease at CT and impairment of gas exchange (P <.01). Probability of functional impairment was increased with multifocal (class II) and diffuse (class III) CT abnormalities, particularly when several lesion types were found concomitantly. Logistic regression analysis demonstrated significant association of parenchymal bands (odds ratio, 6.20; 95% CI: 1.99, 19.22) and subpleural nodules (odds ratio, 3.83; 95% CI: 1.23, 11.89) with functional impairment. Presence and number of pleural plaques did not improve model accuracy for gas exchange impairment prediction (P >.05). CONCLUSION: Thin-section CT grading of interstitial lung disease is useful in assessing the likelihood of pulmonary gas exchange impairment at rest (Dlco) and during exercise (DeltaP[A-a]O(2)/VO(2)) in workers with long-term asbestos exposure.

Sexualidade e gravidez de alto risco / Sexuality and risk hight pregnancy

Durante a gravidez, normalmente a atividade sexual pode e deve ser mantida até o final da gestação. A interrupção do coito só deve ocorrer quando a gravidez extiver a termo, quando houver perda de líquido amniótico ou outras intercorrências clínico-obstétricas. A relação do casal deve ser respeitada e não há nenhum problema com o fato de se atingir o orgasmo - pelo contrário, a sensação de bem-estar que acompanha uma relação fundamentada no amor é muito bem aceita. E o casal sempre encontrará opções que superem eventuais desconfortos relacionados a determinadas posições sexuais