Graphite was incorporated to a polydimethylsiloxane (PDMS) polymer network functionalized with amino groups to obtain an electrode material and used to detect copper ions in aqueous solutions and sugarcane spirit. The polymer network was prepared with PDMS, 3-aminopropyl-trimethoxysilane (APTMS), tetraethyl orthosilicate (TEOS) with addition of graphite to obtain the electrode material. The materials were prepared with different mass concentrations of PDMS: 0, 3, 6, 12 and 18%; and characterized by thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Quasi-reversible behavior was found when studying the [Fe(CN)6]3-/4- redox probe and were electrochemically stable up to 100 consecutive cycles. Electrochemical impedance measurements showed a second time constant at high frequencies for the PDMS electrodes, indicating a second phase in the polymer network with resistive properties, probably due to an increase in the material polymerization resistance. Square wave voltammetry studies were conducted with these electrodes to detect copper(II) ions in aqueous solution. The electrode proposed was applied to determine Cu2+ in a real sample, sugarcane spirit. The PDMS electrodes prepared here presented a potential to be applied as electrochemical sensors for detecting copper ions.

OBJECTIVES:This study aimed to investigate the clinical correlation between angiographic coronary atherosclerosis and N-terminal pro-B-type natriuretic peptide along with other known correlated factors.METHODS:In total, 153 patients with a diagnostic hypothesis of stable angina, unstable angina or acute myocardial infarction were classified as group A (patients with angiographically normal coronary arteries) or group B (patients with angiographic coronary atherosclerosis). The two groups were analyzed with respect to the following factors: gender, age, body mass index, abdominal circumference, smoking, diabetes mellitus, arterial hypertension, early family history of atherosclerosis, statin use, the presence of metabolic syndrome, clinical presentation and biochemical factors, including cholesterol, creatinine and fibrinogen plasma concentrations, monocyte counts and N-terminal pro-B-type natriuretic peptide.RESULTS:Univariate analyses comparing the two groups revealed that group B patients more frequently had diabetes, used statins and had systolic dysfunction, N-terminal pro-B-type natriuretic peptide levels ≥250 pg/mL, fibrinogen levels >500 mg/dL and ≥501 monocytes/mm3 compared with group A patients (p<0.05). Nevertheless, multivariate logistic regression analysis demonstrated that the independent predictors of angiographic coronary atherosclerosis were an N-terminal pro-B-type natriuretic peptide level ≥250 pg/mL, diabetes mellitus and increased monocyte numbers and fibrinogen plasma concentration, regardless of the creatinine level or the presence of systolic dysfunction.CONCLUSIONS:An N-terminal pro-B-type natriuretic peptide plasma concentration of ≥250 pg/mL is an independent predictor of angiographic coronary atherosclerosis.

Se describe una rara asociación de tumor cardíaco y enfermedad coronaria. Un varón de 42 años de edad fue admitido con queja de disnea. El electrocardiograma mostró ritmo sinusal, bloqueo de rama derecha y repolarización anormal de la pared ventricular anterior. El ecocardiograma mostró una estructura con ecogenicidad aumentada dentro de la aurícula izquierda, compatible con tumor cardíaco. El paciente fue enviado a cirugía; se estabilizó y fue dado de alta en el cuarto día post-operatorio sin complicaciones y sin síntomas.

We describe a rare association between cardiac tumor and coronary disease. A 42 years old male was admitted with complaints of dyspnea. The physical examination was unremarkable. The electrocardiogram showed sinus rhythm, with right bundle block and ventricular anterior wall repolarization abnormality. The echocardiogram showed a structure with increased echogenicity inside the left atrium, compatible with cardiac tumor. A surgery was then indicated to remove the tumor. The patient became stable and was discharged in the fourth post-operative day with no symptom and no complication.

Num ecossistema agrícola, a redução do banco de sementes é um dos aspectos mais importantes no manejo de plantas daninhas; e em solos de várzeas, o arroz vermelho (Oryza sativa L.) é atualmente considerado a principal planta daninha. Nesse sentido, conduziu-se um experimento com o objetivo de avaliar a evolução do banco de sementes de arroz vermelho no solo em diferentes sistemas de semeadura de arroz irrigado e em alternativas de manejo do solo de várzea. O experimento foi instalado em campo por dois anos consecutivos na mesma área (safras agrícolas 1996/97 e 1997/98) em Santa Maria, RS, em solo classificado como Planossolo, com infestação média de 516 sementes viáveis de arroz vermelho/m². A estimativa do banco de sementes de arroz vermelho foi realizada através de 10 coletas de solo, utilizando um cilindro com 0,10m de diâmetro a 0,10m de profundidade. Após a coleta, os grãos foram separados do solo e realizado teste de tetrazólio para determinar a quantidade de sementes viáveis na amostra. As coletas foram realizadas antes da instalação do experimento (set/1996), após a colheita do primeiro ano (mai/1997) e após a colheita do segundo ano (mai/1998). Os resultados mostraram que o cultivo do arroz no sistema convencional promove aumento no banco de sementes de arroz vermelho, enquanto que a semeadura de arroz em solo inundado (mix de pré-germinado, prégerminado ou transplante de mudas) é tão eficiente na redução do banco de sementes de arroz vermelho quanto a rotação com o sorgo, o pousio do solo sem a presença de animais e também o preparo de verão.

In an agricultural ecosystem, the redution of weed seed bank is of utmost importance. In lowland areas, red rice (Oryza sativa) is the most important weed. Therefore, an experiment was conducted to evaluate the evolution of the red rice seed bank under different seeding systems and alternatives of soil management. The experiment was conducted during two years (1996/97 and 1997/98 growing seasons) in Santa Maria, RS in Albaqualf soil with an average infestation of 556 viable seeds per square meter. The assessement of the seed bank was conducted by ten samplings using a cylinder with 10cm of diameter and 10cm depth. After each sampling the seeds were separated and the number of viable seeds was determinated by tetrazolium test. The sampling were carried out before establishing the experiment (September 1996) after the first harvest (May 1997) and after the second harvest (May 1998). The results showed that the traditional rice cropping method increases the red rice seed bank, whereas the systems in which the rice is seeded in flooded soil (no tillage water seeded, water seeded and transplanted seedlings) are as efficient in reducing the red rice seed bank as the system that applies crop rotation with sorghum or fallow without the presence of grazing animals or soil tillage during summer.