Physical and mechanical properties of particleboard bamboo waste bonded with urea formaldehyde and castor oil based adhesive

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

Effect of hemolysis on canine, bovine and earn e serum chemistry

Hemolysis is the main cause of biochemical analysis rejection's in veterinary laboratories, however the relative error caused by hemoglobin on serum biochemical profile has not been properly established on several species. In order to establish criteria for aproval and rejection of hemolyzed samples for serum biochemical tests, the hypothesis that hemolysis causes biochemical changes in canine, cattle and horses and that laboratorial error depends on species and hemolysis degree was tested. Thus, non-hemolyzed serum was contaminated with crescent hemoglobin levels and using commercial routine reagents, the serum concentrations of uric acid, albumin, cholesterol, triglycerides and urea, besides the activity of ALT, AST, CK and GUT were quantified in triplicate samples. The relative error was calculated by the comparison between hemolyzed and non-hemolyzed samples. Hemolys is did not cause significant error on the albumin determination in all three species, AST in canine and cattle, ALT in horses, UK and cholesterol in canine. There was a linear increase on uric acid levels in horses and cattle, triglycerides in all three species. A linear increase in serum urea in all species serum, UK and cholesterol in cattle and cholesterol in horses was observed. Serum AST activity on equine serum and ALT in cattle decreased linearly due to hemolysis. It was concluded that hemolysis promotes changes in canine, equine and bovine serum chemistry profile, however the laboratorial error not necessarily compromises the diagnosis in all cases, because the changes depends on species and degree of in vitro hemolysis.

Using 3D Animations in Teaching Chemistry

This paper discuss possibilities of use of 3D animation as a tool for teaching Chemistry support. The research proposes to investigate the conception process and development of educational animations to use in a Blended Learning environment in undergraduate chemistry. Associated with general chemistry teachers, were raised the demands and difficulties on the content transmission, and the most relevant topics, about "Atomic Theory" with propose to create appropriate animations to meeting needs of themes. Thinking about offering more dynamic materials, we elaborate animations in a format of "micro-documentary", with a length between 4 and 7 minutes. We use the narration aloud to the subject-matter understanding, leaving the external text as a complement of the animation. The conclusions are positives, students accepted well the format and they proved are able to remember, organize and systematize several information presented in animations. These skills don't ensure knowledge acquisition, but may be considered prerequisites to learning occur.

Median lethal concentration of formaldehyde and its genotoxic potential in bullfrog tadpoles (Lithobates catesbeianus)

In order to avoid that contaminated frog farms animals escaping in the environment and become potential vector of emergent diseases, studies with disinfection protocol are strictly necessary. The formaldehyde is one of the compounds tested in fungal disinfection protocols and also used in aquaculture. This study aimed to determine the median lethal concentration (LC50-96h) of formaldehyde in bullfrog tadpoles and to evaluate the possible genotoxic effects in acute exposition. Accordingly, the animals were exposed to formaldehyde in the concentrations of 6, 9, 12, 15, and 18 mg L(-1), and after 96 h blood samples were drawn for the micronucleus (MN) test. The LC50-96h was 10.53 mg L(-1), and the MN frequency increased in proportion to the formaldehyde concentrations, with an estimated frequency in the negative control being 1.35 MN/individual. We concluded that formaldehyde is genotoxic to tadpoles of bullfrogs in the tested concentrations, and the choice of this chemical should be contemplated before its use in animals in captivity.

Evaluation and degradation chemistry of orbifloxacin using LC-MS

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

Chemistry and pharmacology of some plants mentioned in the letter of Pero Vaz de Caminha

Brazil has a long tradition in the study of medicinal plants. When the Portuguese arrived to the new colony, Pero Vaz de Caminha, the scriber of the fleet, left the first impressions of the local and the inhabitants. He clearly mentions how the Indians use natural dye as tincture to paint their bodies. This article reviews the phytochemical and pharmacological characteristics of these colorants and other medicinal plants recently identified mentioned in this letter.

Theoretical chemistry: current applications to photochemistry and thermochemistry

A historical perspective is given contrasting challenges and advances in theoretical chemistry at the time the first issue of Theoretical Chemistry Accounts appeared in 1962 and the progress achieved since then as expressed in current state-of-the-art applications in photochemistry and thermochemistry.

INVESTIGATING THE PRESENCE OF THE HISTORY OF SCIENCE IN UNIVERSITY GENERAL CHEMISTRY TEXTBOOKS

INVESTIGATING THE PRESENCE OF THE HISTORY OF SCIENCE IN UNIVERSITY GENERAL CHEMISTRY TEXTBOOKS. This paper aims at analyzing the history of science content of three general chemistry textbooks used in Brazilian universities: the translations of Kotz and Treichel's Chemistry & Chemical Reactivity, Atkins and Jones's Chemical Principles, and Garritz and Chamizo's Quimica. Results revealed different trends for the inclusion of history of science in chemistry teaching. Katz & Treichel and Atkins & Jones used history mainly as curiosity and ornament. Garritz & Chamizo adopted the historical approach as one of the organizing axis of their textbook. Nevertheless, the historical content of the three textbooks may be criticized from current historiographical standpoint.

Synthesis of 1,2,3-triazolylpyranosides through click chemistry reaction

We have developed an efficient method for the synthesis of functionalized C-glycosyl 1,2,3-triazoles through a Cu(1)-promoted azide-alkyne 1,3-dipolar cycloaddition between a TMS-protected C-alkynyl-glycoside and organic azides. The reaction was accelerated by ultrasound irradiation and the addition of a base was not necessary to obtain the 1,2,3-triazole product. Moreover, further manipulation of the products led to chiral molecules with a C-glycoside linkage. (C) 2012 Elsevier Ltd. All rights reserved.

The dual pathway in action: decoupling parallel routes for CO2 production during the oscillatory electro-oxidation of methanol

As in the case of most small organic molecules, the electro-oxidation of methanol to CO2 is believed to proceed through a so-called dual pathway mechanism. The direct pathway proceeds via reactive intermediates such as formaldehyde or formic acid, whereas the indirect pathway occurs in parallel, and proceeds via the formation of adsorbed carbon monoxide (COad). Despite the extensive literature on the electro-oxidation of methanol, no study to date distinguished the production of CO2 from direct and indirect pathways. Working under, far-from-equilibrium, oscillatory conditions, we were able to decouple, for the first time, the direct and indirect pathways that lead to CO2 during the oscillatory electro-oxidation of methanol on platinum. The CO2 production was followed by differential electrochemical mass spectrometry and the individual contributions of parallel pathways were identified by a combination of experiments and numerical simulations. We believe that our report opens some perspectives, particularly as a methodology to be used to identify the role played by surface modifiers in the relative weight of both pathways-a key issue to the effective development of catalysts for low temperature fuel cells.

On the search for potential anti-Trypanosoma cruzi drugs: Synthesis and biological evaluation of 2-hydroxy-3-methylamino and 1,2,3-triazolic naphthoquinoidal compounds obtained by click chemistry reactions

Five 2-hydroxy-3-substituted-aminomethyl naphthoquinones, nine 1,2,3-triazolic para-naphthoquinones, five nor-beta-lapachone-based 1,2,3-triazoles, and several other naphthoquinonoid compounds were synthesized and evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease, continuing our screening program for new trypanocidal compounds. Among all the substances, 16-18, 23, 25-29 and 30-33 were herein described for the first time and fifteen substances were identified as more potent than the standard drug benznidazole, with IC50/24 h values in the range of 10.9-101.5 mu M. Compounds 14 and 19 with Selectivity Index of 18.9 and 6.1 are important structures for further studies. (C) 2012 Elsevier Masson SAS. All rights reserved.

Molecular chemistry and the missing mass problem in planetary nebulae

Context. Detections of molecular lines, mainly from H-2 and CO, reveal molecular material in planetary nebulae. Observations of a variety of molecules suggest that the molecular composition in these objects differs from that found in interstellar clouds or in circumstellar envelopes. The success of the models, which are mostly devoted to explain molecular densities in specific planetary nebulae, is still partial however. Aims. The present study aims at identifying the influence of stellar and nebular properties on the molecular composition of planetary nebulae by means of chemical models. A comparison of theoretical results with those derived from the observations may provide clues to the conditions that favor the presence of a particular molecule. Methods. A self-consistent photoionization numerical code was adapted to simulate cold molecular regions beyond the ionized zone. The code was used to obtain a grid of models and the resulting column densities are compared with those inferred from observations. Results. Our models show that the inclusion of an incident flux of X-rays is required to explain the molecular composition derived for planetary nebulae. We also obtain a more accurate relation for the N(CO)/N(H-2) ratio in these objects. Molecular masses obtained by previous works in the literature were then recalculated, showing that these masses can be underestimated by up to three orders of magnitude. We conclude that the problem of the missing mass in planetary nebulae can be solved by a more accurate calculation of the molecular mass.

An evaluation of dosimetric characteristics of MAGIC gel modified by adding formaldehyde (MAGIC-f)

Purpose: To evaluate the dosimetric characteristics of a new formulation of MAGIC gel, called MAGIC-f, which contains the addition of 3.3% formaldehyde, resulting in a gel with increased thermal stability. Methods: MAGIC-f gel was prepared and stored in hermetically sealed plastic containers. After irradiation, magnetic resonance images (MRI) were acquired to evaluate dose and dose distribution. Dosimetric characterization was performed by means of depth dose measurements, dose response sensitivity and linearity, temporal stability, energy and dose rate dependence, dose integration using sequential beams, temperature influence during MRI acquisition and dose distribution integrity. Results: MAGIC-f depth dose measurements are compatible with the dosimetric table data within +/- 4% uncertainty. The dosimeter's R-2 response varies linearly with dose at least from 0 to 6 Gy. The time-course of the sensitivity of the dosimeter following irradiation, indicated stabilization after 2 weeks. The dosimeter's response to irradiation was altered by 6% when increasing the energy from cobalt beams to 10 MV beams. The dose rate dependence of this new formulation of gel dosimeter is small: less than 2.5% for a variation from 200 to 500 cGy/min, and the dependence with the fractionation scheme is about 50% smaller than for standard MAGIC gel, The dependence on scanning temperature was also verified, and the integrity of the dose distribution was confirmed for a period of 90 days. Conclusions: The results demonstrate the applicability of this new dosimeter in tridimensional dose distribution measurements. (C) 2012 Elsevier Ltd. All rights reserved.