Evaluation of Candida rugosa Lipase Immobilized on Magnetic Nanoparticles in Enzymatic/Chemical Hydroesterification for Biodiesel Production.

This study aimed to (i) prepare functionalized maghemite nanoparticles for immobilization of Candida rugosa lipase (CRL) by covalent binding, (ii) evaluate the application of the immobilized derivative in the hydrolysis of waste cooking oil (WCO) to fatty acids, and (iii) assess the potential of the hydrolyzed material for biodiesel production by hydroesterification. Maghemite (γFeO) obtained by precipitation of FeCl with NHOH served as an efficient support for covalent immobilization of CRL. Fourier-transform infrared spectroscopy and hydrolytic activity analysis indicated that CRL was covalently immobilized on the surface of the maghemite support.

Biodiesel Processing Using Sodium and Potassium Geopolymer Powders as Heterogeneous Catalysts.

This work investigates the catalytic activity of geopolymers produced using two different alkali components (sodium or potassium) and four treatment temperatures (110 to 700 °C) for the methyl transesterification of soybean oil. The geopolymers were prepared with metakaolin as an aluminosilicate source and alkaline activating solutions containing either sodium or potassium in the same molar oxide proportions. The potassium-based formulation displayed a higher specific surface area and lower average pore size (28.

Isolation, in vitro study, and stem cell markers for type A spermatogonia in a Characiformes species.

The objective of this study was to establish a protocol for the characterization, isolation, and culture of type A spermatogonia using specific molecular markers for these cells in fish. To this end, adult Prochilodus lineatus testes were collected and digested enzymatically and the resulting testicular suspension was separated using a discontinuous Percoll gradient, followed by differential plating. The cell cultures obtained were monitored for 15 days and analyzed using the immunofluorescence method with anti-Vasa, anti-GFRα1, and anti-OCT4 antibodies.

Molecular characterization of different preproGnRHs in Astyanax altiparanae (Characiformes): Effects of GnRH on female reproduction.

Gonadotropin-releasing hormone (GnRH) is a key molecule in the initiation of the hypothalamic-pituitary-gonadal axis. Thus, knowledge about GnRH may contribute to the effectiveness of species reproduction. Using a Neotropical tetra Astyanax altiparanae as a fish model species, the GnRH forms were characterized at the molecular level and the role of injected GnRHs in vivo was evaluated.

Follicular Development and Reproductive Characteristics in Four Species of Brazilian Tropidurus Lizards.

The follicular development and reproductive characteristics of four species of oviparous lizards in the Tropidurus torquatus group were anatomically and histologically evaluated. We measured specimens, recorded the number of follicles and eggs, and removed the right ovary of each individual, which we processed according to histological routine and photo-documented. For all species, ovaries were divided into a cortical germinal bed, where oogonia and stage I oocytes are located, and a medullar stroma, where the remaining follicular developmental stages occur.

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Background: Many factors can influence an athlete to consume dietary supplements, such as age, sex and sports, among others. Few studies regarding the prevalence and associated factors are available for athletes, especially in developing countries.

Objective: The aim of the study was to determine the factors associated with the consumption of dietary supplements among Brazilian athletes.