Chemical Substances
Mostrando 1-12 de 539 artigos, teses e dissertações.
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1. AOPs são o futuro da ecotoxicologia?
ARE AOPs THE FUTURE OF ECOTOXICOLOGY? AOPs (Adverse Outcome Pathways) were introduced in the field of ecotoxicology due to the need of replacement of the classic system for assessing adverse results (considering only the mortality of organisms exposed to certain substances or mixtures) to a predictive system based on the measurement of biological events occu
Química Nova. Publicado em: 2022
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2. Effects of chemical straighteners on the hair shaft and scalp
Abstract Background The effects of chemical straighteners on the scalp and hair shaft are not fully known, although such substances are widely used. Hair straightening became popular in Brazil with the use of formaldehyde and its derivatives, despite the prohibition by the current legislation. Objective To identify changes in hair shaft and scalp caused by
Anais Brasileiros de Dermatologia. Publicado em: 2022
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3. Optical sorting technology for waste management from the Boukhadra iron ore mine (NE Algeria)
Abstract Mining processes in the iron ore mine of Boukhadra, Tebessa (NE Algeria) generated thousands of tons of mining wastes every year, which represents a real threat to the environment, leading to hazardous effects for the resident population of the region. The aim of this study is the selective sorting of the Boukhadra mining wastes for valorization. Th
REM - International Engineering Journal. Publicado em: 2022
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4. Biogenic synthesis of silver nanoparticles from thyme extract for functionalization of a bioactive glass produced from rice husk ash
Abstract The rice husk, agro-industrial residue, stands out for having silica, the main oxide former of the bioactive glass. To avoid contamination in this biomaterial, substances with bactericidal properties, like silver can be incorporated. Thus, the objective of this work is the synthesis of silver nanoparticles to functionalize a bioactive glass synthesi
Cerâmica. Publicado em: 2022
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5. Sunscreen lotions in the dermatological prescription: review of concepts and controversies
Abstract The skin is regularly exposed to several environmental aggressions, including solar radiation, whose biological effects can induce sunburn, dyschromia, skin aging and cancer. Among the photoprotection measures, sunscreens comprise a relevant part of the strategy aimed to prevent solar radiation damage and, for effective action, the patient must adhe
Anais Brasileiros de Dermatologia. Publicado em: 2022
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6. Spectroscopic techniques combined with chemometrics to study organic matter in tropical soils with different degrees of pedogenetic evolution
Understanding of the organomineral interactions in soil can elucidate the humic substances (HS) formation and the humification process. This study aimed to structurally characterize the humic acids (HA) formed in tropical soils with different pedogenesis degrees. The HA fraction was extracted from soil samples in the superficial horizons of an Inceptisol and
Química Nova. Publicado em: 2022
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7. The use of white striped chicken breasts on the quality of nuggets and hamburgers
Abstract The objective of this study was to evaluate physically and chemically chicken breasts with different degrees of white striping (WS), as well as its effect on the process and quality of nuggets and hamburgers. Chicken breasts fillets were obtained from male chicken broilers weighing approximately 3 kg at the slaughterhouse and classified based on the
Food Sci. Technol. Publicado em: 2021-09
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8. Molecular Modeling and Chemical Synthesis of New Safrol Oxime Ether Derivatives
Leishmaniasis, a neglected tropical disease with a high worldwide incidence, is considered a public health issue in Minas Gerais and Brazil, with a high degree of morbidity, not to mention the lack of therapeutic arsenal. The cysteine protease (rCPB2.8) and cyclin dependent kinase (CRK3), important enzymes for the parasite’s feasibility, were the targets c
J. Braz. Chem. Soc.. Publicado em: 2021-07
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9. Chemical Characteristics and Antioxidant Activity of Astaxanthin Extracted from Shrimp Residues Using Soybean Oil
Shrimp residues generated by the seafood industrial processing are generally discarded in the environment without any further treatment, leading to a loss of nutritional value such as proteins, lipids, chitin, carotenoids, and minerals. This practice can lead to environmental problems due to the decomposition of these substances in the air. The objective of
J. Braz. Chem. Soc.. Publicado em: 2021-06
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10. CLASSIFICAÇÃO DAS SUBSTÂNCIAS QUÍMICAS: UM CONCEITO POUCO EXPLORADO NA EDUCAÇÃO QUÍMICA
The classification of chemical substances is a concept little explored in Chemistry teaching literature and in Chemistry textbooks at higher and secondary levels. The aim of this paper is to discuss theoretically the importance and contributions of this concept for teaching and learning Chemistry. The History of Chemistry reveals that the chemical criteria f
Quím. Nova. Publicado em: 2021-04
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11. CONSTRUCTION OF A LOW-COST POLARIMETER FOR EDUCATIONAL PURPOSES
This paper describes the construction of a polarimeter for the identification of chemical substances. The device was built with low-cost materials, measures the phenomenon of optical activity and has educational applicability. The measurement of optical activity is achieved through the measurement of the resulting polarized radiation in a photodiode connecte
Quím. Nova. Publicado em: 2021-03
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12. ORBITALS IN GENERAL CHEMISTRY, PART III: CONSEQUENCES FOR TEACHING
In Part III of this series, we undertake a critique of the nature of application of orbitals to describe or to explain the structure and the binding within molecules and materials. Teaching orbitals in introductory chemistry presents five dilemmas that cannot be easily resolved. We thus conclude, based on mathematical realties, that orbitals are not essentia
Quím. Nova. Publicado em: 2021-03