Thermal behavior of corn starch granules modified by acid treatment at 30 and 50°C

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cardiac remodeling induced by 13-cis retinoic acid treatment in acne patients

Background: Currently, 13-cis-retinoic acid (13-cis-RA) is the most effective therapy for acne. Isotretinoin, a first-generation synthetic 13-cis-RA compound, is associated with numerous adverse effects. To investigate the cardiac effects of 13-cis-RA, acne patients receiving 13-cis-RA were studied. Methods: Twenty male patients with acne were enrolled in the study. Patients were treated with a dose of 0.5 mg/kg/d of isotretinoin. All participants were assessed prior to treatment and after 10 weeks of therapy with Doppler-echocardiogram. Results: Patients showed reductions in right atrium vertical diameter, left atrium longitudinal diameter, left atrium volume and left ventricular diastolic diameter over the course of treatment. Significant increases in interventricular septum diastolic thickness, posterior wall diastolic thickness, relative wall relative thickness and left ventricle (LV) mass were observed. The LV mass index showed an increase in ventricular mass and a decrease in the cavity size. Examining LV systolic function, a decrease was observed for the cardiac index. Conclusion: In this study, 10 weeks of 13-cis-RA therapy at a dose of 0.5 mg/kg/d was found to promote concentric-type heart remodeling due to the occurrence of two associated events: heart hypertrophy and hypovolemia. © 2011 Elsevier B.V. All rights reserved.

Antibiotic treatment schemes for very severe community-acquired pneumonia in children: a randomized clinical study

Objective. To compare clinical response to initial empiric treatment with oxacillin plus ceftriaxone and amoxicillin plus clavulanic acid in hospitalized children diagnosed with very severe community-acquired pneumonia (CAP).Methods. A prospective randomized clinical study was conducted among children 2 months to 5 years old with a diagnosis of very severe CAP in the pediatric ward of São Paulo State University Hospital in Botucatu, São Paulo, Brazil, from April 2007 to May 2008. Patients were randomly divided into two groups by type of treatment: an oxacillin/ceftriaxone group (OCG, n = 48) and an amoxicillin/clavulanic acid group (ACG, n = 56). Analyzed outcomes were: time to clinical improvement (fever and tachypnea), time on oxygen therapy, length of stay in hospital, need to widen antimicrobial spectrum, and complications (including pleural effusion).Results. The two groups did not differ statistically for age, sex, symptom duration before admission, or previous antibiotic treatment. Time to improve tachypnea was less among ACG patients than OCG patients (4.8 +/- 2.2 versus 5.8 +/- 2.4 days respectively; P = 0.028), as was length of hospital stay (11.0 +/- 6.2 versus 14.4 +/- 4.5 days respectively; P = 0.002). There were no statistically significant differences between the two groups for fever improvement time, time on oxygen therapy, need to widen antimicrobial spectrum, or frequency of pleural effusion.Conclusions. Both treatment plans are effective in treating very severe CAP in 2-monthto 5-year-old hospitalized children. The only analyzed outcome that favored amoxicillin/clavulanic acid treatment was time required to improve tachypnea.

Effects of corn meal and sulphuric acid on the production of cachaça

Avaliou-se o efeito da adição do fubá de milho no mosto de xarope de cana e o tratamento ácido do pé-de-cuba sobre a microbiota do processo fermentativo, acidez do vinho, grau alcoólico, rendimento e composição da cachaça. O delineamento experimental utilizado foi o de blocos casualizados, no esquema fatorial 2x3 e cinco repetições. A metodologia empregada e as análises foram as recomendadas pelo setor aguardenteiro. Os resultados permitiram concluir que a adição do ácido sulfúrico no pé-de-cuba transferiu a acidez para o vinho, não influenciando na viabilidade das leveduras, rendimento e composição da cachaça. Por outro lado, a acidificação do meio controlou as bactérias láticas no pé-de-cuba. A adição do fubá aumentou a concentração de bactérias lácticas ao final do processo fermentativo e dos álcoois homólogos superiores na cachaça, particularmente, os álcoois propílico e isobutílico.

Evaluation of residual iron in carbon nanotubes purified by acid treatments

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Pore structure characterization of kaolin, metakaolin, and their acid-treated products using small-angle X-ray scattering

Pore structure of dealuminated kaolin and metakaolin was studied by small-angle X-ray scattering (SAXS). Both parent kaolin and metakaolin have about 10% of the total pore volume provided by globular pores with 105 Å mean pore size. Their surface area is about 14 m2/g. Acid dealumination of kaolin causes an increase of its globular pore volume without an appreciable change in the mean pore size, its surface area increasing up to about 90 m2/g. Acid dealumination of metakaolin enhances the globular pore volume, although there is generation of slit-shaped pores with a narrow thickness distribution whose mean value is 14 Å. This interlayer spacing causes an increase in surface area of about 190 m2/g by SAXS. © 1994.

Leaching of Ni and Cu from mine wastes (tailings and slags) using acid solutions and A. ferrooxidans

The objective of this work is to evaluate the acidic and biological leaching of tailings containing Ni/Cu from a flotation and smelting plant. Acidithiobacillus ferrooxidans, strain LR, was used for bioleaching at pH 1.8 and chemical controls were run parallel to that. The acidic leaching was done within 48 hours at pH 0.5 and 1.0. In the slag inoculated flasks the redox potential was high (600 mV), thus indicating oxidative bacterial activity, however, the obtained results after 15 days showed only around 13% Ni and 8% Cu extractions, which were not different to those of the controls. For the flotation tailings bioleaching extractions were approximately 45% for Ni and 16% for Cu while differing figures were obtained for the chemical controls. These were 30% and 12% respectively. Here we could observe that the presence of bacterial activity led to a higher solubility of Ni. Acid leaching of slag showed higher nickel and copper extractions: 56% and 24% respectively at pH 0.5 and 21% and 11% at pH 1.0. However, the acid consumption was 320 and 150 Kg/ton of slag, respectively, both much higher than in bacterial assays. These results indicated that Ni and Cu solubilization from the slag is acid dependent no matter the redox potential or ferric iron concentration of the leaching solution. For flotation tailings, acid treatment showed extractions of 23% for Ni and 16% for copper at pH 0.5 and 22% and 28%, respectively at pH 1.0. The acid consumption was also higher: 220 and 120 Kg/ton, at pH 0.5 and 1.0, respectively. Based on own findings we could observe that acid leaching is found to be more effective for slag, though the acid consumption is much higher, while for the flotation tailings, bacterial leaching seems to be the best alternative. © (2009) Trans Tech Publications.

Biological and structural characterization of a new PLA(2) from the Crotalus durissus collilineatus venom

In the present article we report on the biological characterization and amino acid sequence of a new basic Phospholipases A(2) (PLA(2)) isolated from the Crotalus durissus collilineatus venom (Cdcolli F6), which showed the presence of 122 amino acid residues with a pI value of 8.3, molecular mass of 14 kDa and revealed an amino acid sequence identity of 80% with crotalic PLA(2)s such as Mojave B, Cdt F15, and CROATOX. This homology, however, dropped to 50% if compared to other sources of PLA(2)s such as from the Bothrops snake venom. Also, this PLA(2) induced myonecrosis, although this effect was lower than that of BthTx-I or whole crotoxin and it was able to induce a strong blockage effect on the chick biventer neuromuscular preparation, independently of the presence of the acid subunid (crotapotin). The neurotoxic effect was strongly reduced by pre-incubation with heparin or with anhydrous acetic acid and rho-BPB showed a similar reduction. The rho-BPB did not reduce significantly the myotoxic activity induced by the PLA(2), but the anhydrous acetic acid treatment and the pre-incu-bation of PLA(2) with heparin reduced significantly its effects. This protein showed a strong antimicrobial activity against Xanthomonas axonopodis passiflorae (Gram-negative), which was drastically reduced by incubation of this PLA(2) with rho-BPB, but this effect was marginally reduced after treatment with anhydrous acetic acid. Our findings here allow to speculate that basic amino acid residues on the C-terminal and molecular regions near catalytic site regions such as Calcium binding loop or rho-wing region may be involved in the binding of this PLA(2) to the molecular receptor to induce the neurotoxic effect. The bactericidal effect, however, was completely dependent on the enzymatic activity of this protein.

Body lipid deposition in Nile tilapia fed on rations containing tannin

O objetivo deste trabalho foi avaliar o efeito de fontes e níveis de tanino em rações para tilápia-do-nilo (Oreochromis niloticus), durante a engorda, sobre o desempenho produtivo e deposição lipídica corporal. Foram utilizados 342 peixes, distribuídos em 18 tanques. As rações foram preparadas com milho, variedades de sorgo com baixo e alto teor de tanino, e com ácido tânico a 0,08, 0,34, e 0,60%. Ganho de peso, conversão alimentar aparente e taxa de eficiência protéica não foram influenciados pelos tratamentos. A maior deposição lipídica corporal foi observada nas dietas com ácido tânico (14,39%); a dieta de sorgo com alto teor de tanino resultou em carcaças mais magras (12,01%) do que as de sorgo com baixo teor de tanino (13,31%). Dietas com sorgo proporcionaram menores teores de gordura visceral. A presença de tanino nas rações não prejudicou o desempenho produtivo da tilápia-do-nilo.

Enhancement of thermal stability, strength and extensibility of lipid-based polyurethanes with cellulose-based nanofibers

Cellulose was extracted from lignocellulosic fibers and nanocrystalline cellulose (NC) prepared by alkali treatment of the fiber, steam explosion of the mercerized fiber, bleaching of the steam exploded fiber and finally acid treatment by 5% oxalic acid followed again by steam explosion. The average length and diameter of the NC were between 200-250 nm and 4-5 nm, respectively, in a monodisperse distribution. Different concentrations of the NC (0.1, 0.5, 1.0, 1.5, 2.0 and 2.5% by weight) were dispersed non-covalently into a completely bio-based thermoplastic polyurethane (TPU) derived entirely from oleic acid. The physical properties of the TPU nanocomposites were assessed by Fourier Transform Infra-Red spectroscopy (FTIR), Thermo-Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Dynamic Mechanical Analysis (DMA) and Mechanical Properties Analysis. The nanocomposites demonstrated enhanced stress and elongation at break and improved thermal stability compared to the neat TPU. The best results were obtained with 0.5% of NC in the TPU. The elongation at break of this sample was improved from 178% to 269% and its stress at break from 29.3 to 40.5 MPa. In this and all other samples the glass transition temperature, melting temperature and crystallization behavior were essentially unaffected. This finding suggests a potential method of increasing the strength and the elongation at break of typically brittle and weak lipid-based TPUs without alteration of the other physico-chemical properties of the polymer. (C) 2012 Elsevier Ltd. All rights reserved.

Isolation of nanocellulose from pineapple leaf fibres by steam explosion

Steam explosion process is employed for the successful extraction of cellulose nanofibrils from pineapple leaf fibres for the first time. Steam coupled acid treatment on the pineapple leaf fibres is found to be effective in the depolymerization and defibrillation of the fibre to produce nanofibrils of these fibres. The chemical constituents of the different stages of pineapple fibres undergoing treatment were analyzed according to the ASTM standards. The crystallinity of the fibres is examined from the XRD analysis. Characterization of the fibres by SEM. AFM and TEM supports the evidence for the successful isolation of nanofibrils from pineapple leaf. The developed nanocellulose promises to be a very versatile material having the wide range of biomedical applications and biotechnological applications, such as tissue engineering, drug delivery, wound dressings and medical implants. (C) 2010 Elsevier Ltd. All rights reserved.

THE EFFECT of DENTIN PRETREATMENT on THE MICROTENSILE BOND STRENGTH of SELF-ADHESIVE RESIN CEMENTS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Floculação de leveduras por Lactobacillus fermentum em processos industriais de fermentação alcoólica avaliada por técnica fotométrica

Na produção de álcool por fermentação com leveduras, a floculação manifesta-se como um mecanismo natural de agregação de células. Essa condição pode ser induzida por vários fatores, entre eles, a interação entre bactérias floculentas como Lactobacillus fermentum e as leveduras. Esse fato torna-se prejudicial para o processo, pois tanto nas unidades que se utilizam do sistema de recuperação de células por centrifugação, como nas que não o utilizam, ocorrem perdas excessivas de fermento, em conseqüência dos problemas operacionais decorrentes da floculação, comprometendo seriamente o desempenho industrial. No presente trabalho, avaliou-se a floculação em vinho proveniente de fermentação experimental, sob duas condições de pH de fermento tratado utilizadas como inóculo e temperaturas de fermentação, não se observando diferenças significativas entre elas. Com este estudo, pôde-se ainda avaliar a capacidade de dispersão dos flocos em três condições de pH no tratamento do fermento em fase industrial, mostrando diferenças altamente significativas entre elas. A maior capacidade de dispersão no tratamento do fermento é desejável para o controle da floculação industrial, permitindo a sua centrifugação, com conseqüente separação das bactérias contaminantes do fermento. Essas constatações tornaram-se possíveis pelo emprego da técnica usual de determinação da floculação por espectrofotometria, modificada pela desfloculação prévia das amostras de vinho e fermento, o que conferiu maior estabilidade nas leituras.

Comparative investigation of the cleavage step in the synthesis of model peptide resins: Implications for N-alpha-9-fluorenylmethyloxycarbonyl-solid phase peptide synthesis

Based on our studies of the stability of model peptide-resin linkage in acid media, we previously proposed a rule for resin selection and a final cleavage protocol applicable to the N-alpha-tert-butyloxycarbonyl (Boc)-peptide synthesis strategy. We found that incorrect choices resulted in decreases in the final synthesis yield, which is highly dependent on the peptide sequence, of as high as 30%. The present paper continues along this line of research but examines the N-alpha-9-fluorenylmethyloxycarbonyl (Fmoc)-synthesis strategy. The vasoactive peptide angiotensin II (All, DRVYIHPF) and its [Gly(8)]-All analogue were selected as model peptide resins. Variations in parameters such as the type of spacer group (linker) between the peptide backbone and the resin, as well as in the final acid cleavage protocol, were evaluated. The same methodology employed for the Boc strategy was used in order to establish rules for selection of the most appropriate linker-resin conjugate or of the peptide cleavage method, depending on the sequence to be assembled. The results obtained after treatment with four cleavage solutions and with four types of linker groups indicate that, irrespective of the circumstance, it is not possible to achieve complete removal of the peptide chains from the resin. Moreover, the Phe-attaching peptide at the C-terminal yielded far less cleavage (50-60%.) than that observed with the Gly-bearing sequences at the same position (70-90%). Lastly, the fastest cleavage occurred with reagent K acid treatment and when the peptide was attached to the Wang resin.

Structural and physicochemical characteristics of lintnerized native and sour cassava starches

The comprehension of the structure of starch granules is important for the understanding of its physicochemical properties. Native and sour cassava starches after being analyzed with respect to their pasting properties and baking expansion capacity, were treated with 2.2 N HCl at 38 degreesC for a maximum of nine days. The starch granules remaining after lintnerization were analyzed for amylose content and intrinsic viscosity, by X-ray diffraction, scanning electron microscopy and chromatographic analysis. The results indicated that the acid hydrolysis on all starches occurred in two steps. The first one, with high hydrolysis rate, was characterized by a quick degradation of the amorphous part of the granules whereas the second step, with lower hydrolysis rate, was characterized by a higher resistance of the organized areas of the granules to acid treatment. Most of the amylose chains were found in the amorphous areas of starch granules only a small percentage was involved in the crystalline regions. The microscopic and chromatographic analysis demonstrated that the acid hydrolysis was not able to disrupt the entire granular crystalline structure. Fermented starch showed amylose and/or amylopectin chain fractions resistant to pullulanase, probably due to structural alterations during fermentation.