Preparation and electrochemical characterization of Pt nanoparticles dispersed on niobium oxide

Electrodes consisting of Pt nanoparticles dispersed on thin films of niobium oxide were prepared onto titanium substrates by a sol-gel method. The physical characterization of these electrodes was carried out by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The mean size of the Pt particles was found to be 10.7 nm. The general aspects of the electrochemical behavior were studied by cyclic voltammetry in 1 mol L-1 HClO4 aqueous solution. The response of these electrodes in relation to the oxidation of formaldehyde and methanol in acidic media was also studied.

Preparation of nano-MgO using ultrasonic method and its characteristics

MgO is an important inorganic material, which can be used in many aspects, such as catalyst, toxic-waste remediation agent, adsorbent, and others. In order to make use of MgO, nano-MgO was prepared by ultrasonic method using Mg (CH3COO)2.2H2O as precursor, NaOH aqueous solution as precipitant in this paper. Effect factors on MgO nano-particle size were investigated. Characteristics of samples were measured by TGA, XRD, TEM, and others techniques. The results showed that the size of nano-MgO about 4 nm could be obtained under the following conditions (ultrasonic time 20 min, ultrasonic power 250 W, titration rate of NaOH 0.25 mL/min, NaOH concentration 0.48 mol/L, calcinations temperature 410 °C, calcination time 1.5 h, heating rate of calcination 5 °C/min). It was a very simple and effective method to prepare nano-MgO.

Flow-batch analyser for preparation of calibration standard mixtures in simultaneous multicomponent spectrometric analysis

The application of multivariate calibration techniques to multicomponent analysis by UV-VIS molecular absorption spectrometry is a powerful tool for simultaneous determination of several chemical species. However, when this methodology is accomplished manually, it is slow and laborious, consumes high amounts of reagents and samples, is susceptible to contaminations and presents a high operational cost. To overcome these drawbacks, a flow-batch analyser is proposed in this work. This analyser was developed for automatic preparation of standard calibration and test (or validation) mixtures. It was applied to the simultaneous determination of Cu2+, Mn2+ and Zn2+ in polyvitaminic and polymineral pharmaceutical formulations, using 4-(2-piridilazo) resorcinol as reagent and a UV-VIS spectrophotometer with a photodiode array detector. The results obtained with the proposed system are in good agreement with those obtained by flame atomic absorption spectrometry, which was employed as reference method. With the proposed analyser, the preparation of calibration and test mixtures can be accomplished about four hours, while the manual procedure requires at least two days. Moreover, it consumes smaller amounts of reagents and samples than the manual procedure. After the preparation of calibration and test mixtures, 60 samples h-1 can be carried out with the proposed flow-batch analyser.

Determination of patulin in apple juice by HPLC using a simple and fast sample preparation method

The goal of this work was to develop a simple and rapid preparation method for patulin analysis in apple juice without previous clean-up. This method combined sonication and liquid extraction techniques and was used for determination of patulin in 37 commercial apple juices available on the market in the South of Brazil. The method performance characteristics were determined using a sample obtained in a local market fortified at five concentration levels of patulin and done in triplicates. The coefficient of variation for repeatability at the fortification level of 20.70µg.L-1 was 3.53 % and the recovery 94.63 %, respectively. The correlation coefficient was 0.9996 and agrees with the requirements for a linear analytical method value. The detection limit was 0.21µg.L-1 and the quantification limit 0.70 µg.L-1. Only three of the analyzed samples were upper the allowed level of 50.00 µg.L-1 recommended for the World Health Organization.

Crop coefficient and water consumption of eggplant in no-tillage system and conventional soil preparation

Under organic management in Seropédica-RJ, Brazil, using a weighing lysimeter, the crop coefficients (kc), the maximum evapotranspiration and the productivity of eggplant cultivation under two cropping systems (no tillage with straw plus soil with conventional preparation) were determined. A whole randomized layout with two treatments (no tillage and conventional) and five replicates during 134 days of cultivation were adopted. There were no significant differences in the eggplant cultivation in the two cropping systems, with a maximum commercial productivity obtained from 47.42 Mg ha-1 for the no-tillage system, and 47.91 Mg ha-1 for the conventional tillage. The accumulated ETc was 285.15 and 323.44 mm for the no-tillage and conventional, respectively. The crop coefficients value for the phases: 1 - transplanting, flowering, 2 - flowering-fruiting, 3 - fruit- first harvesting, 4- first harvesting of the final crop cycle was 0.83, 0.77, 0.90 and 0.97 in no-tillage system for the respective phases and for the conventional one 0.81, 1.14, 1.17 and 1.05 for the same steps described above.

Modalities for soil preparation and gypsum application in ultisol: stem productivity of sugarcane

The study was conducted in an area of expansion of sugarcane at Vale do Paraná factory in Suzanápolis city - São Paulo (SP), in Brazil, in the northwestern region of the State of São Paulo. It was used the sugarcane variety RB92-5345, 1.5m of spacing between rows, in an Ultisol. The study aimed to evaluate the productivity of sugarcane and first ratoon and some soil chemical attributes in function of soil tillage and application or not of gypsum. The experimental design was randomized blocks with six treatments, in a factorial 3x2 and six replicates, the main treatments were soil tillage with three equipments, moldboard plow, chisel plow, and heavy harrow, and two secondary treatments with application of 1 t ha-1of gypsum and no gypsum. After each harvest of cane, the soil was characterized as to its fertility indicators in layers of 0.0-0.15; 0.15-0.30 and 0.30-0.45m. Differences in values of soil chemical attributes due to the methods of preparation occurred in the sugarcane did not last until the harvest of the 1st ratoon cane, and also did not influence the crop productivity. The gypsum application resulted in higher values ​​of total recoverable sugar (TRS) and the productivity of tons of stems per hectare (TSH) to sugarcane and 1st ratoon cane, respectively, confirming the initial hypothesis.

Corn productivity in function of surface application of lime in differents management systems and cultural preparation

The evaluation of technologies employed at the agricultural production system such as crop rotation and soil preparation, both associated with crop-livestock integration, is crucial. Therefore, the aim of the present study was to evaluate the incorporation of lime for three no-tillage systems and cultural managements in system of crop-livestock integration, with emphasis on corn grain yield. The experiment was conducted from January 2003 to April 2005 at Selvíria city, MS, in Dystroferric Red Latosol, clay texture. The experimental design was randomized blocks with split plots consisted of three main treatments, aimed the soil physics conditioning and the incorporation of lime: PD - No-no-tillage; CM - minimum no-tillage, and PC - conventional no-tillage; and of two secondary treatments related to the management: rotation and crop succession, with four replications. Data on agronomic traits of maize were analyzed: plant height, stem diameter, height of the first spike insertion, 100 grains weight and grain yield. The results showed that the maize produced under the system of crop-livestock integration is quite feasible, showing that grain yields are comparable to averages in the region and the different soil physical conditioning and incorporation of lime did not influence the corn yield as well as the cultural managements, rotation and succession, did not affect the maize crop behavior after two years of cultivation.

Genetic polymorphisms in the Cytochrome P450 family and squamous cell carcinoma of the oral cavity, pharynx and larynx

Objective:To analyze the genetic polymorphisms of the cytochrome P450 family and their relationship with squamous cell carcinoma of the oral cavity, pharynx and larynx.Methods: We present a narrative literature review, conducted in Pubmed, Lilacs and Cochrane Databases of articles published in the last five years correlating genetic polymorphisms of the cytochrome P450 family and cancer risk in different populations worldwide.Results: We initially found 65 articles and, after selection criteria, 20 case-control studies with various populations worldwide were eligible. The most studied polymorphisms were those of CYP2E1 and CYP1A1 subfamilies. There is little about the other subfamilies. The association found between polymorphisms and cancer risk amounted to a countless number of variables, amongst them: population, selection methods, racial factors and different modes of exposure to carcinogens, genotyping methods, and nomenclature of the polymorphisms.Conclusion: so far, there is no proven link between genetic polymorphisms of cytochrome P450 family and squamous cell carcinoma of the oral cavity, pharynx and larynx relationship.

Use of the amniotic membrane to cover the peritoneal cavity in the reconstruction of the abdominal wall with polypropylene mesh in rats

OBJECTIVE: to evaluate the efficacy of the amniotic membrane used with polypropylene mesh against the formation of adhesions and its influence on healing. METHODS: twenty five female Wistar rats were anesthetized for creating a parietal defect in the anterior abdominal wall. Its correction was made with polypropylene mesh alone and associated with amniotic membrane. In the control group (n=11), the screen was inserted alone. In group A (n=7) we interposed the amniotic membrane between the screen and the abdominal wall. In group B, the amniotic membrane was placed on the mesh, covering it. After seven days, the animals were euthanized for macroscopic and microscopic evaluation of healing. RESULTS: adhesions were observed in all animals except one in the control group. Severe inflammation was observed in all animals in groups A and B and in three of the control group, with significant difference between them (A and B with p=0.01). Pronounced angiogenic activity was noted in one animal in the control group, six in group A and four in group B, with a significant difference between the control group and group A (p=0.002) and group B (p=0.05). The scar collagen was predominantly mature, except in five animals of the control group, with significant difference between the control group and group A (p=0.05) and group B (p=0.05). CONCLUSION: The amniotic membrane did not alter the formation of adhesions in the first postoperative week. There were also pronounced inflammation, high angiogenic activity and predominance of mature collagen fibers, regardless of the anatomical plane that it was inserted in.

Acompanhamento do crescimento dental em Puma concolor mantido em cativeiro

Objetivou-se neste trabalho fazer levantamento sobre a troca de dentição decídua por permanente, notadamente dos dentes caninos e a prevalência de maloclusão em pumas (Puma concolor) manejados nas instituições visitadas no Estado de São Paulo. Para os estudos utilizou-se amostra constituída de 36 pumas, provenientes de 18 instituições mantenedoras de tais espécies em cativeiro no Estado de São Paulo, sendo que três animais com idade de oito meses, irmãos de ninhada, apresentaram retenção dos dentes caninos decíduos e foram acompanha dos por 2 anos e 8 meses. Todos os animais foram examinados, observando se a oclusão estava de acordo com o normal para a espécie. Os dentes foram identificados um a um, examinados diretamente por meio de explorador odontológico. Os animais que apresentaram retenção dos dentes caninos decíduos não foram tratados, pois a maloclusões aparentemente não comprometia a preensão ou mastigação de alimentos, embora apresentassem acúmulo de alimentos ou indutos moles na região dos dentes com espaço interproximal mais reduzido.

Gross anatomical features of the oropharyngeal cavity of the ostrich (Struthio camelus)

Most descriptions of the ostrich oropharynx and oesophagus are superficial and supply little meaningful morphological data. The aim of this investigation is describe the ostrich oropharingeal cavity, in order to supply the deficiency of macroscopic data about this important animal. Five heads of 12 to 14-month-old ostriches of either sex were anatomically dissected to expose the oropharynx. The ostrich oropharynx was "bell-shaped" composed by the maxillary and mandibular ramphoteca. The roof and floor presented two distinct regions different in colour of the mucosa. The rostral region was pale pink contrasting to creamy-pink coloured caudal region. The median longitudinal ridge extended rostrally from the apex of the choana to the tip of the beak in the roof and it is clearly more prominent and rigid than the homolog in the floor that appeared thin and stretched rostrally, continuing caudally surrounding the tongue and the laryngeal mound eventually merging with the oesophageal mucosa. The floor was formed by the interramal region, tongue and laryngeal mound containing shield-shaped glottis. It can be concluded that the present study, in addition to confirming the basic features of the oropharynx previously described for the ostrich, clarified the contradictory information presented in the literature and also provided new, unreported morphological data, some of which may be important when studying nutrition and health in these birds.

Anatomical and radiographic appearance of the capuchin monkey thoracic cavity (Cebus apella)

The capuchin monkey is widespread both north and south of the Legal Amazon and in the Brazilian cerrado. Ten clinically healthy capuchin monkeys were submitted to an anatomical and radiographic study of their thoracic cavities. The radiographic evaluation allowed the description of biometric values associated with the cardiac silhouette and thoracic structures. Application of the VHS (vertebral heart size) method showed positive correlation (P<0.05) with depth of the thoracic cavity, as well as between the body length of vertebrae T3, T4, T5 and T6 and the cardiac length and width. The lung fields showed a diffuse interstitial pattern, more visible in the caudal lung lobes and a bronchial pattern in the middle and cranial lung lobes. The radiographic examination allowed preliminary inferences to be made concerning the syntopy of the thoracic structures and modification of the pulmonary patterns and cardiac anatomy for the capuchin monkey.

Gross morphology of rhea oropharyngeal cavity

The rhea (Rhea americana americana) is an american bird belonging to Ratite's family. Studies related to its morphology are still scarce. This study aims to describe the macroscopic structures of the oropharyngeal cavity. Five heads (2 to 6 months old) formalin preserved were anatomically dissected to expose the oropharynx. The oropharynx of the rhea was "bell-shaped" composed by the maxillary and mandibular rhamphotheca. The roof and floor presented two distinct regions different in colour of the mucosa. The rostral region was pale pink contrasting to grey coloured caudal region. The median longitudinal ridge extended rostrally from the apex of the choana to the tip of the beak in the roof and it is clearly more prominent and rigid than the homolog in the floor that appeared thin and stretched merely along the rostral portion of the regio interramalis. The floor was formed by the interramal region, (regio interramalis) tongue and laryngeal mound containing glove-shaped glottis. This study confirmed the basic morphology of the oropharinx of the rhea. However, important morphological information not previously described is highlighted and contradictory information present in the literature is clarified.

Isolation, expansion and differentiation of cellular progenitors obtained from dental pulp of agouti (Dasyprocta prymnolopha Wagler, 1831)

Abstract: The study aimed to isolate, expand, differentiate and characterize progenitor cells existent in the dental pulp of agouti. The material was washed with PBS solution and dissociated mechanically with the aid of a scalpel blade on plates containing culture medium D-MEM/F-12, and incubated at 5% CO2-37⁰C. The growth curve, CFU assay, osteogenic/adipogenic differentiation and characterization were obtained from the isolation. The cells began to be released from the explant tissue around the 7th day of culture. By day 22 of culture, cells reached 80% confluence. At the UFC test, 81 colonies were counted with 12 days of cultivation. The growth curves before and after freezing showed a regular growth with intense proliferation and clonogenic potential. The cell differentiation showed formation of osteoblasts and fat in culture, starting at 15 days of culture in a specific medium. Flow cytometry (FACs) was as follows: CD34 (positive), CD14 (negative), CD45 (negative), CD73 (positive), CD79 (negative), CD90 (positive), CD105 (positive), demonstrating high specificity and commitment of isolated cells with mesenchymal stem cells strains. These results suggest the existence of a cell population of stem cells with mesenchymal features from the isolated tissue in the explants of agouti dental pulp, a potential model for study of stem cell strains obtained from the pulp tissue.

Numerical study on mixed convection in a horizontal flow past a square porous cavity using UNIFAES scheme

Mixed convection on the flow past a heated length and past a porous cavity located in a horizontal wall bounding a saturated porous medium is numerically simulated. The cavity is heated from below. The steady-state regime is studied for several intensities of the buoyancy effects due to temperature variations. The influences of Péclet and Rayleigh numbers on the flow pattern and the temperature distributions are examined. Local and global Nusselt numbers are reported for the heated surface. The convective-diffusive fluxes at the volume boundaries are represented using the UNIFAES, Unified Finite Approach Exponential-type Scheme, with the Power-Law approximation to reduce the computing time. The conditions established by Rivas for the quadratic order of accuracy of the central differencing to be maintained in irregular grids are shown to be extensible to other quadratic schemes, including UNIFAES, so that accuracy estimates could be obtained.