Search

Beneficiation of manganese ores has been conducted around the world by circuits composed basically of crushing, screening and spiral classifier. Therefore, solely the coarse size fractions (and commonly the richest) are actually recovered: "lump" (-75+9mm) and "sinter feed" (-9+0.15mm). In the industrial plant which processes the ore from the Azul Mine-PA, the overflow of the spiral classifier (- 0.15mm) is disposed of in a tailings dam because it bears a low Mn content (<10%) and high kaolinite content (70%). This paper reports the findings of a process development conducted on laboratory scale with the aim of concentrating Mn-bearing minerals from the tailings of the Azul Mine-PA (7% of Mn and 70% of kaolinite). The process is composed of desliming (-10µm), followed by reverse cationic flotation of kaolinite (rougher, scavenger) at pH~5. Results indicate that the reverse cationic flotation in the acid medium, when utilizing amide amine as collector and in the presence of a silicate activator and a dispersing agent could be a possible route for the concentration of tailings that had previously been deslimed at 10µm. The results yielded a mass recovery of 18%, a metallurgical recovery of 50% and a 32% Mn concentrate which may be mixed with current high grade products, increasing the overall recovery of the plant. [ABSTRACT FROM AUTHOR]

The central idea of current article is to (re)establish a dialogue between poetry and philosophy, (re)connecting them with the existential human condition. It is important to listen to the poetry of the music Roda-viva by Chico Buarque de Holanda and, based on the thought of the Italian philosopher Giorgio Agamben, unveil the sense by which current politics has become biopolitics. At the same time, it reworks the thought that the work of art (in this case, the poetry) may emit opinion on our existential condition which is or perhaps has always been engaged in a constant dispute between the power over the life and power of life. [ABSTRACT FROM AUTHOR]

This article attempts a brief analysis of the Controversy of Valladolid, its relationship with the beginnings of human rights and the emergence of foucaultian biopower. Such controversy occurred in the city of Valladolid, Spain, in the years 1550 and 1551, from Fray Bartolome de Las Casas, prosecutor and defender of American Indians, and also advocate and protector of Human Rights, and the theologian and philosopher Juan Ginés de Sepúlveda for the benefit of the conquest of the Americas and the enslavement of the Indians of that region subjugated by Spain. This represents an important event in relation to human rights, because moving the primacy of the american revolution with its Declaration of Independence and the french revolution, the Declaration of the Rights of Men and Citizens, placing the sixteenth century, Spain and New World an as important landmarks. Finally, this shift relocates in a few centuries before the birth of foucaultian biopower and the biopolitics, which dates from the century XVII and mid-century XVIII, anticipating its contours in two centuries. [ABSTRACT FROM AUTHOR]

Abstract: Two mutations – Factor V Leiden (1691G > A) and the 20210G > A on the Prothrombin gene – are key risk factors for a frequent and potentially fatal disorder called Venous Thromboembolism. These molecular alterations can be investigated using real-time Polymerase Chain Reaction (PCR) with Fluorescence Resonance Energy Transfer (FRET) probes and distinct DNA pools for both factors. The objective of this paper is to present an application of Taguchi Experimental Design Method to determine the best parameters adjustment of a Molecular Assays Process in order to obtain the best diagnostic result for Venous Thromboembolism investigation. The complete process contains six three-level factors which usually demands 729 experiments to obtain the final result, if using a Full Factorial Array. In this research, a Taguchi L27 Orthogonal Array is chosen to optimize the analysis and reduce the number of experiments to 27 without degrading the final result accuracy. The application of this method can lessen the time and cost necessary to achieve the best operation condition for a required performance. The results is proven in practice and confirmed that the Taguchi method can really offer a good approach for clinical assay efficiency and effectiveness improvement even though the clinical diagnostics can be based on the use of qualitative techniques. [Copyright &y& Elsevier]

• Rhodizonate ion is a member of the oxocarbon family. • It has been used to generate complexes with Mn, Co, Ni, Cu and Zn ions. • Complexes have been obtained in innert atmosphere. • X-ray diffraction has shown complexes are Pmmm for Mn, Co, Ni and Zn complexes and P2/m for copper. • Rhodizonate loses D 6h symmetry and several new bands can be seen in the Raman spectra. In this work a series of metal complexes containing the rhodizonate ion have been synthesized and characterized by means of structural and spectroscopic measurements. Compounds of general formula MC 6 O 6.nH 2 O, where M = Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) were carefully obtained in an inert atmosphere, and the resulting complexes have been analyzed by powder X-ray technique, showing that manganese, cobalt, nickel and zinc compounds all present the same similar arrangement; the qualitative phase analysis indicate the Pmmm space group for manganese, cobalt, nickel and zinc salts, and P2/m for the copper salt. The unit cell volumes were determined, and they grow approximately with the number of water molecules in the structure measured by elemental and thermogravimetric analysis. The vibrational spectra are in concordance with the X-ray diffraction results since the salts of manganese, cobalt, nickel and zinc show a remarkably similar spectral profile, whereas the copper salt, shows a different spectral profile. It was observed that the number of bands in the Raman spectra of the compounds is greatly increased compared to the free rhodizonate ion. This fact is justified by the lower symmetry due to the complexation of the metal site. The vibrational modes related with the C=O stretching in the 1700–1500 cm−1 region are the most influenced with the metal coordination showing large displacements and band splitting. This last fact strongly supports the loss of symmetry experienced by the oxocarbon ion when coordinated to the metal centers in the complexes. [ABSTRACT FROM AUTHOR]

This work deals with the synthesis and spectroscopic characterization of novel complexes involving the coordination of croconate (C 5 O 5)2- and 5,5′-dimethyl-2,2′-bipyridyl (DmBpy) ligands to the transition metal ions Co2+ and Cu2+. Two complexes involving the croconate species with the DmBpy ligand were obtained. The complex [Cu(C 5 O 5)(DmBpy)(H 2 O)].H 2 O (1) crystallizes in a monoclinic system, belonging to the P21/c space group and Z equal to four, whereas[Co(C 5 O 5)(DmBpy)(H 2 O) 2 (2) crystallizes in a triclinic system and belonging to the P-1 space group and Z equal to four. The Cu(II) complex presents a slightly distorted square base pyramid geometry, presenting a water molecule at the vertical position, whereas Co(II) compound shows an octahedral geometry with two water molecules at the vertices. In both compounds croconate ions act as a building block, and the nitrogenous ligand is the spacer agent, giving rise to the 3D structure. The vibrational analysis (Raman and infrared) supports the crystallographic data, and several band markers are identified in order to understand the supramolecular interactions, such as the stretching modes ν CC /ν CN at 1600 and 1498 cm−1, respectively, shifted by the coordination to higher wavenumbers in both compounds (1604 and 1507 cm−1, and 1604 and 1508 cm−1, for (1) and (2) respectively), thus strongly corroborating the coordination of the ligand to the metal site through the nitrogen atoms present in the pyridine moiety. On the other hand, the band at 1718 cm−1, assigned to the (CO) stretching mode from croconate ion, can be used as the main band marker, due to the observed shift caused by the coordination to the metal center. [ABSTRACT FROM AUTHOR]

Guerra, MA Jr, Caldas, LA, Souza, HL, Tallis, J, Duncan, MJ, and Guimarães-Ferreira, L. The effects of physical fitness on postactivation potentiation in professional soccer athletes. J Strength Cond Res 36(6): 1643–1647, 2022—To investigate the relationship of the response to postactivation potentiation (PAP) with scores of physical fitness. Twenty-four professional male soccer players undertook tests of agility, muscular power, aerobic capacity, and body composition. Conditioning activities (CAs) were performed consisting of plyometrics exercises and sprints with sled towing. In the first and second sessions, body composition, agility, power, and aerobic capacity were assessed. At the third session, countermovement jumps (CMJ) were performed with 1, 3, and 5 minutes after the execution of the CA. Significant differences were found for CMJ height 1, 3, and 5 minutes after the CA compared with baseline values (3.58, 5.10, 5.48%, respectively). There was a significant positive correlation between the level of general physical fitness and PAP (CMJ height increase) 5 minutes after (r = 0.73). When the athletes were divided into groups with higher and lower physical fitness, the CA caused a significant increase in CMJ height in both groups, but a significant difference (p < 0.05) was observed at all times after PAP induction, with better performance in higher versus lower fitness level. The results suggest that plyometrics exercises associated with sled towing sprints as a CA result in an increase in CMJ performance in athletes and that physical fitness directly influences the PAP occurrence, with higher fit players demonstrating an enhanced PAP response. [ABSTRACT FROM AUTHOR]

An abstract of the article "Resveratrol as a protective agent of goat sperm submitted to sex sorting in discontinuous Percoll gradient - preliminary results" by Ellen C. B. Silva and colleagues is presented.

The aim was to verify the efficiency of different glycerol concentrations (1%, 3%, and 5%) for cryopreservation of stallion semen. After semen collection, sperm cells were evaluated for motility and acrosin activity. The semen was divided into three equal parts and resuspended in freezing diluent without glycerol in a 1:1 proportion and were incubated for 20 minutes at room temperature. Immediately after centrifugation for 10 minutes at 600g and discarding the supernatant, each pellet was diluted with the same diluent and further centrifuged for 10 minutes. After the second centrifugation, each pellet received freezing glycerol-containing diluent under concentrations of 1%, 3%, and 5% and was loaded in 4mL macro-tubes. These macro-tubes were placed in liquid nitrogen vapor for 15 minutes for immediate immersion in liquid nitrogen and storage at -196°C. After thawing at 50°C for 40 seconds, semen samples were initially evaluated for sperm motility and acrosin activity. Moreover, semen was also incubated at 37ºC and evaluated for sperm motility after 60 and 120 minutes in a thermoresistance test (TRT). Immediately after thawing and during the TRT, both progressive and total sperm motility was lower in 1% glycerol (P0.05) between these two later concentrations. The acrosin activity in fresh semen was only greater (P0.05) between these later glycerol concentrations. In conclusion, based on sperm motility and acrosin activity, that 3% and 5% glycerol concentrations are suitable for stallion semen cryopreservation. [ABSTRACT FROM AUTHOR]

Ca 2 Y 8 (SiO 4) 6 O 2 phosphors doped with Eu3+ and Dy3+ and co-doped with Eu3+/Dy3+ were synthesized via sol-gel method. The materials showed apatite-type silicates crystallized in a hexagonal unit cell. The photoluminescence spectra of the Eu3+-doped silicates exhibited an intense red emission and the Dy3+-doped phosphors showed intense emissions in the blue (4F 9/2 → 6H 15/2) and yellow (4F 9/2 → 6H 13/2) regions. The Eu3+/Dy3+-co-doped phosphors presented improvements when compared with the spectra of the Dy3+-single doped materials by means of compensation in the red component of the emission spectrum. The chromaticity diagram presented a tunable color emission. The energy transfer from Dy3+ to Eu3+ was confirmed based on the photoluminescence intensities and decay curves. The temperature dependence of photoluminescence demonstrated that the synthesized phosphors did not reach thermal quenching, even when subjected to a temperature of 250 °C. • Eu3+/Dy3+ co-doped and single doped Eu3+ or Dy3+ silicates with apatite-type structure was obtained by sol-gel process. • The materials exhibited excitation bands in the range 250–500 nm, which makes them efficiently excited by near-UV. • The incorporation of Eu3+ ions improves the photoluminescence spectra of Dy3+ doped materials. • Interesting values of activation energy for single doped materials. [ABSTRACT FROM AUTHOR]

An abstract of the article "Cryopreservation of ram epididymis spermatozoa post-slaughter - A feasible biotechnique?" by Sildivane Silva, Felipe Almeida and colleagues is presented.