Use of heterogeneous catalysts in methylic biodiesel production induced by microwave irradiation

The effect of different heterogeneous catalysts on the microwave-assisted transesterification of sunflower oil for the production of methylic biodiesel in a monomode microwave reactor is described. The experiments were carried out at 70 ºC with a 16:1 methanolsunflower oil molar ratio and different heterogeneous basic and acidic catalysts. The results showed that the microwave-heated reactions occur up to four times faster than those carried out with conventional heating. The reactions were performed with 24 catalysts; pure calcium oxide (CaO) and potassium carbonate, either pure or supported by alumina (K2CO3/Al2O3), were the most efficient catalysts.

A NEW HOMOGENEOUS ELECTROCATALYST FOR ELECTROCHEMICAL CARBONYLATION OF METHANOL TO DIMETHYL CARBONATE

Electrosynthesis of dimethyl carbonate (DMC) from methanol and carbon monoxide using an Cu(phen)Cl2 catalyst was achieved at room temperature and atmospheric pressure. The catalytic activity of the ligand 1,10-phenanthroline (phen) and the catalytic system were analyzed. The IR characterization results for the complex catalyst showed that copper ions were coordinated by nitrogen atoms of phen. In addition, the effects of the influencing factors, such as reaction time (t), reaction temperature (T) and the surface area of the working electrode (SWE) were studied.

INFLUÊNCIA DO CATALISADOR EM SOLUÇÕES POLIMÉRICAS PARA O PREPARO DE GÉIS ORGÂNICOS DE RESORCINOL-FORMALDEÍDO

Resorcinol-formaldehyde (RF) organic gels have been extensively used to produce carbon aerogels. The organic gel synthesis parameters greatly affect the structure of the resulting aerogel. In this study, the influence of the catalyst quantity on the polymeric solution sol-gel process was investigated. Sodium carbonate was used as a basic catalyst. RF gels were synthesized with a resorcinol to formaldehyde molar ratio of 0.5, a resorcinol to catalyst (R/C) molar ratio equal to 50 or 300, and a resorcinol to solvent ratio of 0.1 g mL-1. The sol-gel process was evaluated in situ by Fourier transform infrared spectroscopy using a universal attenuated total reflectance sensor and measurements of the kinematic viscosity. The techniques showed the evolution of the sol-gel process, and the results showed that the lower catalyst quantity induced a higher gel point, with a lower viscosity at the gel point. Differential scanning calorimetry was used to investigate the thermal behavior of the RF dried gel, and results showed that the exothermic event related to the curing process was shifted to higher temperatures for solutions containing higher R/C ratios.

FAST GC-FID METHOD FOR MONITORING ACIDIC AND BASIC CATALYTIC TRANSESTERIFICATION REACTIONS IN VEGETABLE OILS TO METHYL ESTER BIODIESEL PREPARATION

A fast gas chromatography with a flame ionisation detector (GC-FID) method for the simultaneous analysis of methyl palmitate (C16:0), stearate (C18:0), oleate (C18:1), linoleate (C18:2) and linolenate (C18:3) in biodiesel samples was proposed. The analysis was conducted in a customised ionic-liquid stationary-phase capillary, SLB-IL 111, with a length of 14 m, an internal diameter of 0.10 mm, a film thickness of 0.08 µm and operated isothermally at 160 °C using hydrogen as the carrier gas at a rate of 50 cm s-1 in run time about 3 min. Once methyl myristate (C14:0) is present lower than 0.5% m/m in real samples it was used as an internal standard. The method was successful applied to monitoring basic and acidic catalysis transesterification reactions of vegetable oils such as soybean, canola, corn, sunflower and those used in frying process.

Influence of the medium (strongly acid or basic) over the electrochemical properties of the nitrate selective electrode

A nitrate selective electrode was prepared for use in an aggresive medium (high acidic or basic concentration). It is demonstrated that the depending E graph with respect to pNO3- has not a Nernstian response in concentration acidic range upper 0.1 mol/L H2SO4. The observed behaviour is supposed to be due to the formation of a dimeric anion HN2O6-.

Morphological and thermal analyses of flexible polyurethane foams containing commercial calcium carbonate

One filler often utilized in flexible polyurethane foams is calcium carbonate (CaCO3) because it is non-abrasiveness, non-toxicity and facilitated pigmentation. However, it is observed that the excess of commercial CaCO3 utilized in industry possibly causing permanent deformations and damaging the quality of the final product. The effect of different concentrations of commercial CaCO3, in flexible foams, was studied. Different concentrations of CaCO3 were used for the synthesis of flexible polyurethane foams, which were submitted to morphological and thermal analyses to verify the alterations provoked by the progressive introduction of this filler.

Photoelectrocatalytical degradation of basic blue 41 dye using nanoporous semiconductor of Ti/TiO2

O presente trabalho investiga a degradação fotoeletrocatalítica do corante Azul Básico 41 (AB 41) amplamente utilizado na tintura de fibras sintéticas, utilizando um semicondutor Ti/TiO2 como fotoanodo. 100% de degradação foi obtida após 60 min de tratamento de 8,33x10-5 mol L-1 do corante em 0,1 mol L−1 Na2SO4, pH 2 sob densidade de corrente de 0,40 mA cm−2 e irradiação UV. Ainda foi obtido 80% de remoção de carbono orgânico total, cuja oxidação segue uma reação de pseudo-primeira ordem com constante de velocidade inicial de -0,040 mim-1 e uma eficiência de corrente de 51%. Os resultados são superiores á fotocatálise convencional nas mesmas condições sem a polarização do fotoanodo que leva a 65% de mineralização sob constante de velocidade de -0,024 mim-1.

Low-fidelity bench models for basic surgical skills training during undergraduate medical education

It is remarkable the reduction in the number of medical students choosing general surgery as a career. In this context, new possibilities in the field of surgical education should be developed to combat this lack of interest. In this study, a program of surgical training based on learning with models of low-fidelity bench is designed as a complementary alternative to the various methodologies in the teaching of basic surgical skills during medical education, and to develop personal interests in career choice.

Basic skills for outpatient surgery in medical graduation

Medical students must have domain of basic surgery skills before starting more advanced stages of surgical learning. The authors present a practical and reproducible system of operative techniques circuit, idealized and often applied to the fourth year medical students of a private educational institution. This method has enabled accurate assessment of students' skills, improving their performance and preparing them for more advanced stages of the surgical learning.

Analysis of trophic responses in lesioned brain: focus on basic fibroblast growth factor mechanisms

The actions of fibroblast growth factors (FGFs), particularly the basic form (bFGF), have been described in a large number of cells and include mitogenicity, angiogenicity and wound repair. The present review discusses the presence of the bFGF protein and messenger RNA as well as the presence of the FGF receptor messenger RNA in the rodent brain by means of semiquantitative radioactive in situ hybridization in combination with immunohistochemistry. Chemical and mechanical injuries to the brain trigger a reduction in neurotransmitter synthesis and neuronal death which are accompanied by astroglial reaction. The altered synthesis of bFGF following brain lesions or stimulation was analyzed. Lesions of the central nervous system trigger bFGF gene expression by neurons and/or activated astrocytes, depending on the type of lesion and time post-manipulation. The changes in bFGF messenger RNA are frequently accompanied by a subsequent increase of bFGF immunoreactivity in astrocytes in the lesioned pathway. The reactive astrocytes and injured neurons synthesize increased amount of bFGF, which may act as a paracrine/autocrine factor, protecting neurons from death and also stimulating neuronal plasticity and tissue repair

Effect of a Brazilian regional basic diet on the prevalence of caries in rats

The aim of the present study was to determine the effect of a regional basic diet (RBD) on the prevalence of caries in the molar teeth of rats of both sexes aged 23 days. The animals were divided into six groups of 10 rats each receiving the following diets for 30 and 60 days after weaning: RBD, a cariogenic diet, and a commercial diet. The prevalence and penetration of caries in the molar teeth of the rats was then analyzed. The RBD produced caries in 37.5% of the teeth of animals fed 30 days, and in 83.4% of animals fed 60 days, while the cariogenic diet produced caries in 72.5% and 77.5% of the teeth of animals fed 30 and 60 days, respectively. Rats fed the RBD for 30 days had caries in the enamel in 38% of their teeth, 48% had superficial dentin caries, and 7.5% moderate dentin caries. The effect of the RBD did not differ significantly from that of the cariogenic diet in terms of the presence of caries in rats fed 60 days. The penetration depth of the caries produced by the RBD was the same as that produced by the cariogenic diet. Our results show that the RBD has the same cariogenic potential as the cariogenic diet. Since the RBD is the only option for the low-income population, there should be a study of how to compensate for the cariogenicity of this diet.

A conceptual and practical overview of cDNA microarray technology: implications for basic and clinical sciences

cDNA microarray is an innovative technology that facilitates the analysis of the expression of thousands of genes simultaneously. The utilization of this methodology, which is rapidly evolving, requires a combination of expertise from the biological, mathematical and statistical sciences. In this review, we attempt to provide an overview of the principles of cDNA microarray technology, the practical concerns of the analytical processing of the data obtained, the correlation of this methodology with other data analysis methods such as immunohistochemistry in tissue microarrays, and the cDNA microarray application in distinct areas of the basic and clinical sciences.

cDNA and deduced primary structure of basic phospholipase A2 with neurotoxic activity from the venom secretion of the Crotalus durissus collilineatus rattlesnake

To illustrate the construction of precursor complementary DNAs, we isolated mRNAs from whole venom samples. After reverse transcription polymerase chain reaction (RT-PCR), we amplified the cDNA coding for a neurotoxic protein, phospholipase A2 D49 (PLA2 D49), from the venom of Crotalus durissus collilineatus (Cdc PLA2). The cDNA encoding Cdc PLA2 from whole venom was sequenced. The deduced amino acid sequence of this cDNA has high overall sequence identity with the group II PLA2 protein family. Cdc PLA2 has 14 cysteine residues capable of forming seven disulfide bonds that characterize this group of PLA2 enzymes. Cdc PLA2 was isolated using conventional Sephadex G75 column chromatography and reverse-phase high performance liquid chromatography (RP-HPLC). The molecular mass was estimated using matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. We tested the neuromuscular blocking activities on chick biventer cervicis neuromuscular tissue. Phylogenetic analysis of Cdc PLA2 showed the existence of two lines of N6-PLA2, denominated F24 and S24. Apparently, the sequences of the New World’s N6-F24-PLA2 are similar to those of the agkistrodotoxin from the Asian genus Gloydius. The sequences of N6-S24-PLA2 are similar to the sequence of trimucrotoxin from the genus Protobothrops, found in the Old World.

Normal skin and hypertrophic scar fibroblasts differentially regulate collagen and fibronectin expression as well as mitochondrial membrane potential in response to basic fibroblast growth factor

Basic fibroblast growth factor (bFGF) regulates skin wound healing; however, the underlying mechanism remains to be defined. In the present study, we determined the effects of bFGF on the regulation of cell growth as well as collagen and fibronectin expression in fibroblasts from normal human skin and from hypertrophic scars. We then explored the involvement of mitochondria in mediating bFGF-inducedeffects on the fibroblasts. We isolated and cultivated normal and hypertrophic scar fibroblasts from tissue biopsies of patients who underwent plastic surgery for repairing hypertrophic scars. The fibroblasts were then treated with different concentrations of bFGF (ranging from 0.1 to 1000 ng/mL). The growth of hypertrophic scar fibroblasts became slower with selective inhibition of type I collagen production after exposure to bFGF. However, type III collagen expression was affected in both normal and hypertrophic scar fibroblasts. Moreover, fibronectin expression in the normal fibroblasts was up-regulated after bFGF treatment. bFGF (1000 ng/mL) also induced mitochondrial depolarization in hypertrophic scar fibroblasts (P < 0.01). The cellular ATP level decreased in hypertrophic scar fibroblasts (P < 0.05), while it increased in the normal fibroblasts following treatment with bFGF (P < 0.01). These data suggest that bFGF has differential effects and mechanisms on fibroblasts of the normal skin and hypertrophic scars, indicating that bFGF may play a role in the early phase of skin wound healing and post-burn scar formation.

Osteogenesis induced in goat bone marrow progenitor cells by recombinant adenovirus coexpressing bone morphogenetic protein 2 and basic fibroblast growth factor

Bone morphogenetic protein 2 (BMP2) and basic fibroblast growth factor (bFGF) have been shown to exhibit a synergistic effect to promote bone repair and healing. In this study, we constructed a novel adenovirus with high coexpression of BMP2 and bFGF and evaluated its effect on osteogenic differentiation of goat bone marrow progenitor cells (BMPCs). Recombinant adenovirus Ad-BMP2-bFGF was constructed by using the T2A sequence. BMPCs were isolated from goats by density gradient centrifugation and adherent cell culture, and were then infected with Ad-BMP2-bFGF or Ad-BMP2. Expression of BMP2 and bFGF was detected by ELISA, and alkaline phosphatase (ALP) activity was detected by an ALP assay kit. In addition, von Kossa staining and immunocytochemical staining of collagen II were performed on BMPCs 21 days after infection. There was a high coexpression of BMP2 and bFGF in BMPCs infected with Ad-BMP2-bFGF. Twenty-one days after infection, ALP activity was significantly higher in BMPCs infected with Ad-BMP2-bFGF than in those infected with Ad-BMP2. Larger and more mineralized calcium nodules, as well as stronger collagen II staining, were observed in BMPCs infected with Ad-BMP2-bFGF than in those infected with Ad-BMP2. In summary, we developed a novel adenovirus vector Ad-BMP2-bFGF for simultaneous high coexpression of BMP2 and bFGF, which could induce BMPCs to differentiate efficiently into osteoblasts.