Determination of cadmium in biodiesel using microemulsion and electrothermal atomization atomic absorption spectrometry.

This work aimed to prepare biodiesel microemulsions for the subsequent quantification of cadmium via graphite furnace atomic absorption spectrometry (GFAAS). The biodiesel samples were prepared using n-propanol as an emulsifier, 10% (v/v) nitric acid as the aqueous phase, and biodiesel. Pseudoternary phase diagrams were constructed to determine the microemulsion region with the specified components. The optimized conditions for microemulsion formation were 57.6% (v/v) n-propanol, 21.2% (v/v) biodiesel, and 21.2% (v/v) nitric acid solution. The stability of the microemulsified system was investigated using aqueous and organic standards, and the system was found to be stable for at least 240 min. The applied pyrolysis and atomization temperatures were 800 and 2000 °C, respectively, and 5 µg of aluminum was used as the chemical modifier. The obtained limits of detection and quantification were 0.2 and 0.5 µg kg(-1), respectively, and the characteristic mass was 1.6 pg. The precision, expressed as the relative standard deviation (% R.S.D., n = 10), was 2.5% for a sample with a cadmium concentration of 6.5 µg kg(-1). The accuracy was determined from addition and recovery experiments, with results varying from 93 to 108% recovery. This study demonstrates that the proposed method based on the use of a microemulsion formation in sample preparation can be applied as an efficient alternative for the determination of cadmium in biodiesel by GFAAS. Cadmium determination in biodiesel samples of different origins (soybean, corn, cotton, and sunflower) was evaluated after acid digestion using the inductively coupled plasma-mass spectrometry (ICP-MS) technique, and the obtained results were compared to the results obtained using the proposed method. The paired t test (95% confidence level) did not show significant differences. The concentrations of cadmium found ranged from 5.3 to 8.0 µg kg(-1).

Nutritional status of zinc in children with Down syndrome.

Experimental and clinical studies have established that zinc metabolism is altered in individuals with Down syndrome (DS). The present study intends to evaluate the nutritional status of zinc in children with DS by determining their biochemical and dietary parameters. The investigation was carried out on a group of children with DS (n = 35) and compared with a control group (n = 33), both aging between 4 and 11 years. Weight-for-age, height-for-age, and weight-for-height indexes and diet were evaluated by using a 3-day dietary record. Zinc was evaluated in plasma, erythrocytes, and 24-h urine collection by using the method of atomic absorption spectroscopy. The frequency of short stature was higher in children with DS. Both groups presented high protein content, adequate concentrations of lipids and carbohydrates, and deficit in calories. Adequate zinc intake was observed in 40% of children with DS and in 67% of the control group. Zinc concentrations were significantly lower in plasma and urine and higher in erythrocytes of children with DS. The results allowed us to conclude that the altered zinc nutritional status of individuals with Down syndrome contributes to clinical disturbances that usually appear with aging in these patients.

Associative diazotrophic bacteria in grass roots and soils from heavy metal contaminated sites

This work aimed to evaluate density of associative diazotrophic bacteria populations in soil and grass root samples from heavy metal contaminated sites, and to characterize isolates from these populations, both, phenotypically (Zinc, Cadmium and NaCl tolerance in vitro, and protein profiles) and genotypically (16S rDNA sequencing), as compared to type strains of known diazotrophic species. Densities were evaluated by using NFb, Fam and JNFb media, commonly used for enrichment cultures of diazotrophic bacteria. Bacterial densities found in soil and grass root samples from contaminated sites were similar to those reported for agricultural soils. Azospirillum spp. isolates from contaminated sites and type strains from non-contaminated sites varied substantially in their in vitro tolerance to Zn+2 and Cd+2, being Cd+2 more toxic than Zn+2. Among the most tolerant isolates (UFLA 1S, 1R, S181, S34 and S22), some (1R, S34 and S22) were more tolerant to heavy metals than rhizobia from tropical and temperate soils. The majority of the isolates tolerant to heavy metals were also tolerant to salt stress as indicated by their ability to grow in solid medium supplemented with 30 g L-1 NaCl. Five isolates exhibited high dissimilarity in protein profiles, and the 16S rDNA sequence analysis of two of them revealed new sequences for Azospirillum.

Objetivou-se avaliar a densidade de populações de bactérias diazotróficas associativas em amostras de solos e de raízes de gramíneas oriundas de sítios contaminados com metais pesados, e caracterizar isolados destas populações através da análise fenotípica (tolerância aos metais pesados zinco e cádmio e à NaCl in vitro, perfis protéicos), e genotípica (seqüenciamento de 16S rDNA), comparados às estirpes tipo das mesmas espécies. As densidades foram avaliadas nos meios NFb, Fam e LGI, comumente utilizados para culturas de enriquecimento de populações de bactérias diazotróficas associativas. As densidades encontradas em amostras de solo e raiz de sítios contaminados foram semelhantes àquelas relatadas na literatura para solos agrícolas. Isolados de Azospirillum spp. de solos contaminados e estirpes tipo oriundas de solos não contaminados variaram substancialmente com relação à tolerância a Zn+2 e Cd+2, sendo que Cd+2 mais tóxico que Zn+2. Dentre os isolados mais tolerantes (UFLA 1S, 1R, S181, S34, e S22), alguns(1R, S34 e S22) foram mais tolerantes a metais pesados que rizóbios isolados de solos de áreas tropicais e temperadas. A maioria dos isolados mais tolerantes a metais pesados também foi tolerante ao estresse salino, o que foi indicado por seu crescimento em meio sólido suplementado com 30 g L-1 de NaCl in vitro. Cinco isolados apresentaram alta dissimilaridade em perfis protéicos e o seqüenciamento do gene 16S rDNA em dois deles revelou que apresentam novas seqüências de Azospirillum.

Associative diazotrophic bacteria in grass roots and soils from heavy metal contaminated sites.

This work aimed to evaluate density of associative diazotrophic bacteria populations in soil and grass root samples from heavy metal contaminated sites, and to characterize isolates from these populations, both, phenotypically (Zinc, Cadmium and NaCl tolerance in vitro, and protein profiles) and genotypically (16S rDNA sequencing), as compared to type strains of known diazotrophic species. Densities were evaluated by using NFb, Fam and JNFb media, commonly used for enrichment cultures of diazotrophic bacteria. Bacterial densities found in soil and grass root samples from contaminated sites were similar to those reported for agricultural soils. Azospirillum spp. isolates from contaminated sites and type strains from non-contaminated sites varied substantially in their in vitro tolerance to Zn+2 and Cd+2, being Cd+2 more toxic than Zn+2. Among the most tolerant isolates (UFLA 1S, 1R, S181, S34 and S22), some (1R, S34 and S22) were more tolerant to heavy metals than rhizobia from tropical and temperate soils. The majority of the isolates tolerant to heavy metals were also tolerant to salt stress as indicated by their ability to grow in solid medium supplemented with 30 g L(-1) NaCl. Five isolates exhibited high dissimilarity in protein profiles, and the 16S rDNA sequence analysis of two of them revealed new sequences for Azospirillum.

Rinossinusite crônica em pacientes infectados pelo vírus da imunodeficiência humana: avaliação clínica e radiológica / Chronic rhinosinusitis in HIV-infected patients: radiological and clinical evaluation

O advento dos inibidores de protease, aumentando a sobrevida dos pacientes infectados com HIV aumentou a procura destes pacientes por médicos otorrinolaringologistas, já que 40 por cento a 70 por cento deles podem apresentar alguma alteração otorrinolaringológica. OBJETIVIVOS: Objetivamos, nesse estudo, comparar os achados radiológicos e sintomatologia nasossinusal entre pacientes infectados com HIV e pacientes com AIDS, com rinossinusite crônica. A literatura sobre o assunto é revisada e discutida. FORMA DE ESTUDO: clínico prospectivo com coorte transversal. CASUíSTICA E MÉTODOS: Prospectivamente, 39 pacientes em uso de drogas antiretrovirais foram divididos em 2 grupos: pacientes com diagnóstico de AIDS (grupo I) e aqueles apenas infectados pelo HIV (grupo II). Estes grupos foram comparados clinicamente, quanto à contagem de células CD4+ e avaliação tomográfica dos seios paranasais. RESULTADOS: Os pacientes dos grupos I e II apresentaram média de células CD4+ de 118 cél/10-9l e 377 cél/10-9l, respectivamente. Na comparação dos achados tomográficos pelo sistema de Lund e Mackay, o grupo I apresentou escore médio de 12 e o grupo II apresentou média de escore de 5,63 (p<0,001), sendo a febre e a secreção pós-nasal mais prevalente no grupo I (p<0,001). CONCLUSÃO: A prevalência da sinusite crônica nos pacientes infectados pelo HIV foi de 12 por cento. Os sintomas da rinossinusite foram similares nos pacientes sem AIDS e com AIDS, com exceção da presença de febre. Os pacientes com AIDS apresentaram alterações radiológicas mais extensas do que os pacientes HIV positivos.

Chronic rhinosinusitis in HIV-infected patients: radiological and clinical evaluation.

UNLABELLED: The advent of protease inhibitors, which enhances the survival rate of HIV-infected individuals, leads patients to search for otorhinolaryngologists, as 40-70% of them may present some sort of otorhinolaryngological disorder. AIM: We aimed at comparing the CT scan findings and the nasosinusal complaints of HIV-infected and AIDS patients with clinical diagnosis of chronic rhinosinusitis. The literature on the subject is revised and discussed. STUDY DESIGN: Clinical prospective with transversal cohort. MATERIAL AND METHODS: Prospectively, 39 patients with chronic rhinosinusitis, in use of antiretroviral therapy, were included in the present study and divided into two groups: patients with diagnosis of AIDS (group I) and those infected by HIV (group II). Clinical and laboratorial assessments, with CD4+ cell count and CT evaluation, were performed and compared among groups I and II. RESULTS: Group I and II presented mean CD4+ cell count of 118 cells/10-9l and 377 cells/10-9l, respectively. Comparison of the tomographic findings by the Lund-Mackay staging system presented a score of 12 for group I and 5.63 (pd" 0.001) for group II. Fever and postnasal discharge were more prevalent in group I (pd" 0.001). CONCLUSIONS: In our Service, prevalence of chronic rhinosinusitis in HIV-infected patients was 12%. AIDS patients had a higher incidence of fever and postnasal discharge than those of group II. Moreover, extensive radiological findings were prevalent in patients with AIDS (group I) than in HIV-infected individuals (group II).

Perdas auditivas congênitas e adquiridas na infância / Congenital and Adquired Deafness in Childhood

A deficiência auditiva na infância constitui grave problema médico e social que altera a capacidade de comunicação e aprendizado - e muitas vezes exclui a criança do convívio social. Objetivo: O objetivo deste trabalho é demonstrar a dificuldade de se obter um diagnóstico etiológico preciso, a importância da prevenção da surdez evitável e do diagnóstico precoce da deficiência auditiva na infância. Material e métodos: Esta pesquisa foi realizada no instituto Felipe Smaldone (escola especializada na estimulação e desenvolvimento do deficiente auditivo), em Belém /PA, no período de dezembro de 1996 a fevereiro de 1997. Foram catalogadas aí 150 crianças, na faixa etária de 2 a 13 anos, de ambos os sexos, dando-se importância principalmente às possíveis causas de deficiência auditiva na infância, e se relacionando também o tipo e o grau de deficiência auditiva. Resultados: Nos resultados observouse o predomínio das causas passíveis de prevenção, como a rubéola congênita (32 casos - 22%), meningite (20 casos - 13%) e o uso de drogas ototóxicas (14 casos - 9%). Conclusão: Não se pode deixar de enfatizar o grande número de casos que permaneceram com origem desconhecida devido principalmente a má informação, desconhecimento ou omissão dos pais e familiares no momento do interrogatório, o que demonstra a grande dificuldade em se obter um diagnóstico etiológico preciso, constituindo assim um desfio ao otorrinolaringologista.

The childhood deafness constitutes a serious social medical problem which impairs both communication and learning abilities, reflecting many times on a poor social interaction of the child. Purposes: The purposes of this work are: to demonstrate the difficulty of providing patients with a precise etiologic diagnosis, the importance of preventing the available deafness and that of the early diagnosis for the childhood deafness. Material and method: This research has been developed at Felipe Smaldone Institute (a speciality school to teach children deafness) from Belém /PA, in the period within December 1996 and February 1997. Meanwhile,150 children from both sexes between the ages of 3 and 13 years have been registered, giving importance mainly to the possible causes for the childhood deafness and relating the type and degree of deafness. Results: The result showed predomination of those causes which are available, such as: congenit rubeolla (32 cases 22%), meningitis (20 cases - 13%), and the use of ototoxis drugs (14 cases - 9%). Conclusion: It's important to emphasize the large number of cases whose origins remain unidentified due to lack of information or patents' omission which accounts for the difficulty in obtaining a precise etiological diagnosis and thus still defying otorhynolaringologists.