Evaluación termodinámica de la adición de calcio y magnesio a un Ultisol

An experiment was conducted to determine the effects of two calcium sources on the chemistry of an Ultisol at various magnesium levels. A 2 x 4 x 3 complete factorial experimenta! design had two calcium sources [Ca(OH)2, CaSO4]; four calcium levels: control (0 Ca added), 1x Ca (1 meq Ca/meq Al), 2x Ca (2 meq Ca/meq Al), 3x Ca (3 meq Ca/meq Al), and three levels of magnesium: Control (0, Mg), 1x Mg (10% CEC), and 2x Mg (20% CEC). The addition of Ca(OH)2 increased the pH of the soil to approximately the following values: Control - 4.40; 1x Ca - 6.40; 2x Ca - 6.70; 3x Ca - 6.90. This rise in pH more than doubled the sites available for exchangeable cations as pH dependent charges were created. A 20% decrease in exchangeable magnesium was observed without a consequent increase in the levels of magnesium in solution. This finding suggests that a fixation mechanism was precluding magnesium from becoming available, a condition which may create magnesium deficiency problems for the crops grown in these soils.The addition of magnesium to these samples increased their levels of soluble and exchangeable magnesium but had little effect on the overall fixation of magnesium. A decrease in pH in those samples previously limed with Ca(OH)2 caused a dramatic increase in the levels of calcium and magnesium in solution as a result of the release of cations from pH dependent charges in the case of calcium as well as the liberation of the magnesium possibly being held as a Mg-Al precipitate in the case of magnesium.Se realizó un experinemto para determinar el efecto de dos fuentes de calcio en la química de un Ultisol a varios niveles de magnesio. El diseño experimental consistió de un factorial 2 x 4 x 3 con dos fuentes de calcio: [Ca(OH)2, CaSO4], cuatro niveles de calcio: control (0 Ca), 1x Ca (1 meq Ca/meq Al), 2x Ca (2 meq Ca/meq Al) y tres niveles de magnesio: control (0 Mg), 1x Mg (10% del CEC total), 2x Mg (20% del CEC total). La adición de Ca(OH)2, causó un incremento en el pH del suelo en la siguiente proporción: control, 4.40; 1x Ca, 6.40; 2x Ca, 6.70; 3x Ca - 6.90. Este aumento en pH más que duplicó la capacidad de intercambio catiónico del suelo. Sin embargo, el magnesio intercambiable disminuyó en un 20% a consecuencia del incremento en pH. Tampoco se observó ningún incremento en los niveles de magnesio en solución. Los resultados indican que un mecanismo de fijación evitó que el magnesio se hiciera disponible. La adición de magnesio al suelo causó un aumento en los niveles de magnesio intercambiable y en solución, pero no tuvo efecto alguno en el mecanismo de fijación de magnesio. Una reducción en el pH de las muestras previamente encaladas [ Ca(OH)2] causó un aumento considerable en los niveles de calcio y magnesio en solución. Esto se debe a la liberación de ambos cationes de las cargas dependientes de pH, además de la liberación del magnesio previamente fijado

Evaluación termodinámica de la adición de calcio y magnesio a un Ultisol: II CaS04

An experiment was conducted to evaluate the effects of CaS04 additions on the chemical properties of an Ultisol. Four levels of calcium and three levels of magnesium were combined in a 4 x 3 complete factorial experimental design. As expected, the addition of CaS04 resulted in significant increases in the levels of calcium in solution. Furthermore, a decrease in the amount of exchangeable magnesium was observed. This was in turn reflected in an increase in the concentration of magnesium in solution. The correlation between the amount of magnesium in the exchange phase and in solution suggests that the fixation phenomenon frequently observed in limed soils does not occur when CaS04  is used. To evaluate the effect of increases in pH in these samples, NaOH was added a month after CaS04 addition. As in the case of Ca(OH)2, a decrease in the levels of magnesium in solution was observed. This led us to conclude that the presence of SO42- can not prevent the fixation of magnesium, and that aluminum and pH might be the controlling factors of said mechanism.Se condujo un experimento con el propósito de determinar los efectos de la aplicación de CaS04 a un Ultisol de la montaña. Cuatro niveles de calcio y tres niveles de magnesio se combinaron en un diseño experimental factorial completo 4 x 3. La aplicación de CaS04 causó un incremento significativo en los niveles de calcio en solución. Esto estuvo acompañado por una disminución en los niveles de magnesio intercambiable y por un aumento significativo en los niveles de magnesio en solución. La relación entre los niveles de magnesio intercambiable y magnesio en solución sugiere que el mecanismo de fijación de magnesio típico en suelos ácidos que han sido encalados no ocurre si se utiliza CaS04. Para evaluar los efectos de incrementos en pH en estas muestras, le añadimos NaOH a las mismas un mes luego de la aplicación de CaS04. Los aumentos en pH observados estuvieron acompañados de una disminución en los niveles de magnesio en solución similares a los observados con Ca(OH)2. Por tal motivo se concluyó que la presencia de SO4 2- no pudo prevenir la fijación de magnesio y que el aluminio y el pH son los factores que controlan dicho mecanismo

Editorial: Obesogenic Environmental Conditions Affect Neurodevelopment and Neurodegeneration

Editorial on the Research Topic. Obesogenic Environmental Conditions Affect Neurodevelopment and Neurodegeneratio

Study X-ray photoelectron spectroscopy determination of interactions between gold nanoparticles and epidermal growth factor for potential use in biomedicine

Nowadays, biomedical applications of gold nanoparticles coupled with Epidermal Growth Factor have attracted huge attention because of its theranostic activity, which could be useful for diagnosis and treatment of neurodegenerative diseases. Therefore, there is a great interest to know the nature of the intermolecular interactions between the gold nanoparticles and epidermal growth factor (EGF). A two-step synthesis was performed. In the first step, gold nanoparticles were synthesized by chemical reduction of tetrachloroauric acid using sodium citrate as reducing and capping agent. Secondly, gold nanoparticles were coupled with EGF. The obtained nanoparticles were characterized by ultraviolet-visible spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and zeta-potential before and after being coupled with the EGF. Gold nanoparticles with an average diameter of 8.09 nm were obtained. After coupled with EGF, the particle average diameter increased to 9.14 nm. X-ray photoelectron spectroscopy showed an electrostatic interaction between gold nanoparticles and EGF. Zeta potential corroborated these results. Thus, it was possible for the first time to identify the interactions between these two chemical species. Since gold nanoparticles may act as carriers of EGF, these results illustrate the great potential for the use of this bionanocomposite in neurodegenerative disease treatment.UAEME

Efecto de un suplemento alimenticio a base de insumos naturales y componentes bioactivos de siete raíces sobre el comportamiento sexual en ratas

The present study aimed to determine the effect of a food supplement based on natural inputs and bioactive components of plant species on sexual behavior. It is an experimental, prospective and longitudinal investigation. For the test, 150 albino rats were used: 75 females and 75 males of the Holtzmann breed of 12 weeks of age, with an average weight of 200 to 250 g. (males) and 150 - 200 g. (females). Two products were evaluated: One that contained the extract of the roots of seven plant species at doses of 200 and 400mg / kg and Two that contained the product one plus chestnut flour and Sacha inchi at a dose of 830mg / kg. The trial was carried out for 10 weeks and the evaluations were carried out at the eighth, ninth and tenth weeks (days 1, 7 and 14 respectively). Likewise, the evaluation of the biochemical, hematological, testosterone and prostate-specific antigen (PSA) parameters was carried out. Products One at a dose of 400mg / kg and Two at a dose of 830mg / kg showed a significant effect on sexual behavior compared with the control and standard groups (sildenafil 5mg / kg). There were no changes at the biochemical or hematological level. It is concluded that the tested products had an effect on sexual behavior by increasing libido in male rats, without side effects on biochemical and hematological parameters.El presente estudio tuvo como objetivo determinar el efecto de un suplemento alimenticio a base de insumos naturales y componentes bioactivos de especies vegetales sobre el comportamiento sexual. Es una investigación experimental, prospectiva y longitudinal. Para el ensayo se utilizó 150 ratas albinas: 75 hembras y 75 machos de raza Holtzmann de 12 semanas de edad, con un peso promedio de 200 a 250 g. (machos) y de 150 – 200 g. (hembras). Se evaluaron dos productos: Uno que contenía el extracto de las raíces de siete especies vegetales a dosis de 200 y 400mg/kg y Dos que contenía el producto uno más harina de castaña y Sacha inchi a dosis de 830mg/kg. El ensayo se realizó por 10 semanas y las evaluaciones se ejecutaron a la octava, novena y décima semanas (días 1, 7 y 14 respectivamente). Asimismo, se realizó la evaluación de los parámetros bioquímicos, hematológicos, testosterona y antígeno prostático-específico (PSA). Los productos Uno a dosis de 400mg/kg y Dos a dosis de 830mg/kg presentaron efecto significativo sobre el comportamiento sexual comparados con los grupos control y el estándar (sildenafilo 5mg/kg). No se presentaron cambios a nivel bioquímico ni hematológico. Se concluye que los productos ensayados presentaron efecto sobre el comportamiento sexual aumentando la líbido en las ratas machos, sin efectos secundarios sobre los parámetros bioquímicos y hematológicos

Cationic exchange in nanosized ZnFe₂O₄ spinel revealed by experimental and simulated near-edge absorption structure

The nonequilibrium cation site occupancy in nanosized zinc ferrites ( ∼ 6 – 13 nm ) with different degree of inversion ( ∼ 0.2 to 0.4) was investigated using Fe and Zn K -edge x-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure, and magnetic measurements. The very good agreement between experimental and ab initio calculations on the Zn K -edge XANES region clearly shows the large Zn²⁺ ( A ) → Zn²⁺ [ B ] transference that takes place in addition to the well-identified Fe³⁺ [ B ] → Fe³⁺ ( A ) one, without altering the long-range structural order. XANES spectra features as a function of the spinel inversion were shown to depend on the configuration of the ligand shells surrounding the absorbing atom. This XANES approach provides a direct way to sense cationic inversion in these Zn-containing spinel ferrites. We also demonstrated that a mechanical crystallization takes place on nanocrystalline spinel that causes an increase of both grain and magnetic sizes and, simultaneously, generates a significant augment of the inversion.Instituto de Física La Plat

Return to sport soccer after anterior cruciate ligament reconstruction: ISAKOS consensus

Many factors can affect the return to pivoting sports, after an Anterior Cruciate Ligament Reconstruction. Prehabilitation, rehabilitation, surgical and psychological aspects play an essential role in the decision to return to sports. The purpose of this study is to reach an international consensus about the best conditions for returning to sports in soccer-one of the most demanding level I pivoting sports after anterior cruciate ligament (ACL) reconstruction

Sulfated Polysaccharide Extracted from the Green Algae Codium bernabei: Physicochemical Characterization and Antioxidant, Anticoagulant and Antitumor Activity

Codium bernabei is a green alga that grows on Chilean coasts. The composition of its structural polysaccharides is still unknown. Hence, the aim of this work is to isolate and characterize the hot water extracted polysaccharide fractions. For this purpose, the water extracts were further precipitated in alcohol (TPs) and acid media (APs), respectively. Both fractions were characterized using different physicochemical techniques such as GC-MS, GPC, FTIR, TGA, and SEM. It is confirmed that the extracted fractions are mainly made of sulfated galactan unit, with a degree of sulfation of 19.3% (TPs) and 17.4% (ATs) and a protein content of 3.5% in APs and 15.6% in TPs. Other neutral sugars such as xylose, glucose, galactose, fucose, mannose, and arabinose were found in a molar ratio (0.05:0.6:1.0:0.02:0.14:0.11) for TPs and (0.05:0.31:1.0:0.03:0.1:0.13) for ATs. The molecular weight of the polysaccharide samples was lower than 20 kDa. Both polysaccharides were thermally stable (Tonset > 190 °C) and showed antioxidant activity according to the ABTS•+ and DPPH tests, where TPs fractions had higher scavenging activity (35%) compared to the APs fractions. The PT and APTTS assays were used to measure the anticoagulant activity of the polysaccharide fractions. In general, the PT activity of the TPs and APs was not different from normal plasma values. The exception was the TPs treatment at 1000 µg mL−1 concentration. The APTTS test revealed that clotting time for both polysaccharides was prolonged regarding normal values at 1000 µg mL−1. Finally, the antitumor test in colorectal carcinoma (HTC-116) cell line, breast cancer (MCF-7) and human leukemia (HL-60) cell lines showed the cytotoxic effect of TPs and APs. Those results suggest the potential biotechnological application of sulfate galactan polysaccharides isolated from a Chilean marine resource

Super-W(infinity) Asymptotic Symmetry of Higher-Spin AdS(3) Supergravity

We consider (2+1)-dimensional (N, M)-extended higher-spin anti-de Sitter supergravity and study its asymptotic symmetries. The theory is described by the Chern-Simons action based on a real, infinite-dimensional higher-spin superalgebra. We specify consistent boundary conditions on the higher-spin super-gauge connection corresponding to asymptotically anti-de Sitter spacetimes. We then determine the residual gauge transformations that preserve these asymptotic conditions and compute their Poisson bracket algebra. We find that the asymptotic symmetry is enhanced from the higher-spin superalgebra to some (N,M)-extended super-W(infinity) nonlinear superalgebra. The latter has the same classical central charge as pure Einstein gravity. Special attention is paid to the (1,1)-case. Truncation to the bosonic sector yields the previously found W(infinity) algebra, while truncation to the underlying finite-dimensional superalgebra reproduces the N-extended superconformal algebra (in its nonlinear version for N>2). We discuss string theory realization of these higher-spin anti-de Sitter supergravity theories as well as relations to previous treatments of super-W(infinity) in the literature.Comment: References added. (N>2)-Extended supersymmetric models argued to be rigid with respect to lambda-deformation. Comments on G(3)-case adde