Cubic PdNP-based air-breathing cathodes integrated in glucose hybrid biofuel cells.

Cubic Pd nanoparticles (PdNPs) were synthesized using ascorbic acid as a reducing agent and were evaluated for the catalytic oxygen reduction reaction. PdNPs were confined with multiwalled carbon nanotube (MWCNT) dispersions to form black suspensions and these inks were dropcast onto glassy carbon electrodes. Different nanoparticle sizes were synthesized and investigated upon oxygen reduction capacities (onset potential and electrocatalytic current densities) under O2 saturated conditions at varying pH values. Strong evidence of O2 diffusion limitation was demonstrated. In order to overcome oxygen concentration and diffusion limitations in solution, we used a gas diffusion layer to create a PdNP-based air-breathing cathode, which delivered -1.5 mA cm(-2) at 0.0 V with an onset potential of 0.4 V. This air-breathing cathode was combined with a specially designed phenanthrolinequinone/glucose dehydrogenase-based anode to form a complete glucose/O2 hybrid bio-fuel cell providing an open circuit voltage of 0.554 V and delivering a maximal power output of 184 ± 21 µW cm(-2) at 0.19 V and pH 7.0.

[The cerebrospinal fluid in bacterial meningitis]. / Aspectos dos líquidos cefalorraquidianos nas meningites bacterianas.

Samples of 1815 cerebrospinal fluid (CSF) were studied in a meningitis outbreak during 1989 in São Paulo, Brazil. Neisseria meningitis 56% with 44% type B, Haemophilus influenzae 17%, from which 72% in children (days to 3-year-old) and Streptococcus pneumoniae 14% from which 60% in children (day to 1-year-old) of 443 (24%) of all strains. Cytochemistry study showed: purulent or turbidity aspects in 70 to 79% positive bacterioscopy or culture of CSF; white cells count > 500/mm3; glucose < 45 mg/dl; protein > 90 mg/dl in 90% of all patients. We concluded that: CSF prognostic factors: (aspect and cytochemistry) were correlated with bacterial meningitis. Bacterioscopy and positive cultures were correlated to NM, SP and HI isolation from these patients (Goodman Test).

[Acute pneumonia treatment with a new antibiotic (tobramycin) (author's transl)]. / Tratamento de pneumonias agudas com um novo antibiótico (tobramicina).

The authors have studied a new antibiotic Tobramycin in 30 patients with acute infectious pulmonary disease, denominated type I, II and III, according to associated factors, severity and previous pulmonary alterations, being 29 patients included in type II and III. The pneumonia diagnosis has obeyed to clinical, laboratorial, radiological and microbiological criteria. The results after the Tobramycin therapy in 28 evaluable cases were: 3 failures and 25 therapeutic successes. The gram negative bacteria predominated among the causative pathogens and, in 14 patients, strains of Klebisiella Enterobacter group were isolated. The M.I.C. for the pathogenic isolated bacteria in acute pulmonary processes was less than 1,0 microgram/ml in 26 cases. Adverse reactions were observed in 13 patients, from which 9 have presented only laboratorial alterations. The remaining 4 patients have also presented clinical manifestations. These findings were similar to those reported for other aminoglicosides.

[Blood cultures-bacteriological and drug resistance culture (author's transl)]. / Hemocultura.--Aspectos bacteriológicos e resisténcia a drogas.

Blood cultures of 24 patients from the Hospital das Clinicas da Faculdade de ciências Médicas e Biológicas de Botucatu showed a prevalence of gram-negative isolates (83%) over gram-positive (16%). Among the microorganisms Salmonella typhimurium was the most frequent (25%) followed by Klepsiella sp. (21%) and Escherichia coli (17%). It was also observed that the main cuase of death was the largest occurrence of Salmonella typhimurium and Pseudomonas aeruginosa among the isolates. Regarding drug resistance gentamycin revealed more active than other antibiotic tested.