Peroxidase activity of dimanganese(III) complexes with the [Mn2(μ-OAc)(μ-OR)2]3+ core

Catalytic activity of three dinuclear MnIII complexes of general formula [Mn2(μ-OAc)(μ-OMe)(L)]BPh4 (H3L = 1,5-bis[(2-hydroxy-5-X-benzyl)(2-pyridylmethyl)amino] pentan-3-ol, 1: X = H, 2: X = OMe, 3: X = Br) in the oxidation of phenol, 2,6-dimethoxyphenol and wood pulp by H2O2 has been investigated. The role of pH, electronic properties of the ligand and metal coordination environment on the ability of these complexes to activate H2O2 has been examined. The three catalysts showed similar activity independently of the aromatic substituent in the ligand and were found to be 2-3 times more active at pH 9.00 than at neutral pH. Bleaching of Kraft pulp by H2O2 activated by 1 in alkaline media decreased the kappa number of the pulp by 16%, at room temperature and low catalyst concentration, without damage of cellulose fibers. It was found that the exchange of the methoxo- and acetato-bridges by an oxo-bridge reduces the catalytic activity of these compounds, probably by direct binding of phenolate to a vacant site on the metal center.Fil: Biava, Hernan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Signorella, Sandra Rosanna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Ariel - Volume 10 Number 2

Executive Editors Madalyn Schaefgen David Reich Business Manager David Reich News Editors Medical College Edward Zurad CAHS John Guardiani World Mark Zwanger Features Editors Meg Trexler Jim O\u27Brien Editorials Editor Jeffrey Banyas Photography and Sports Editor Stuart Singer Commons Editor Brenda Peterso

Obtención, caracterización y estudios de actividad de catalizadores de Mn con potencial aplicación en fotosíntesis artificial

Se sintetizaron dos complejos de diMn (C1 y C2) que fueron caracterizados espectroscópicamente. Se los adsorbió sobre nanopartículas de TiO2 y se obtuvieron isotermas de adsorción que se ajustaron con la ecuación de Freundlich. Se encontró que la adsorción sobre TiO2, modificó la estructura o el estado de oxidación de los complejos. En solución, C2@TiO2 mostró capacidad para generar especies Mn-O-Mn en alto estado de oxidación y mayor estabilidad que C1@TiO2. Al evaluar la capacidad de C2@TiO2, en contacto con Ru(bipy)32+ y [Co(NH3)5Cl]Cl2, para catalizar la descomposición fotoinducida de agua a pH 7,8, se observó desprendimiento de oxígeno durante la iluminación, poniendo de manifiesto que la especie generada en la superficie del TiO2 posee el poder oxidante suficiente para catalizar la oxidación de agua por cuatro electrones en las condiciones ensayadasFil: Richezzi, Micaela. Universidad Nacional de RosarioFil: Signorella, Sandra. Universidad Nacional de Rosari

Functional modeling of the MnCAT active site with a dimanganese(III) complex of an unsymmetrical polydentate N 3 O 3 ligand

A new diMn III complex, [Mn 2 L(OAc) 2 (H 2 O)](BPh 4 )·3H 2 O (1), obtained with the unsymmetrical N 3 O 3 -ligand H 3 L = 1-[N-(2-pyridylmethyl),N-(2-hydroxybenzyl)amino]-3-[N′-(2-hydroxybenzyl),N′-(benzyl)amino]propan-2-ol, has been prepared and characterized. The unsymmetrical hexadentate ligand L 3− leads to coordination dissymmetry (dissimilar donor atoms) around each Mn ion (N 2 O 4 and NO 4 (solvent), respectively) leaving one labile site on one of the two Mn ions that facilitates interaction of the metal center with H 2 O 2 , as in Mn catalase. 1 is able to catalyze H 2 O 2 disproportionation in acetonitrile, with second-order rate constant k cat = 23.9(2) M −1 s −1 . The accessibility of the Mn II 2 state and the closeness of the two one-electron reduction processes suggest 1 employs Mn III 2 /Mn II 2 oxidation states for catalysis.Fil: Ledesma, Gabriela Nanci. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Anxolabehere Mallart, Elodie. Université Paris Diderot - Paris 7; FranciaFil: Sabater, Laurent. Universite de Toulouse; FranciaFil: Hureau, Christelle. Universite de Toulouse; FranciaFil: Signorella, Sandra Rosanna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentin

Death After Marijuana Use in a 27-Year-Old Male: a Case Report

The dangers of marijuana use are well documented across most body systems. We report a 27-year-old male who ingested marijuana and then experienced an ST-elevation myocardial infarction, subsequent cerebrovascular accident, and death within the span of a week. Toxicology reports were positive for THC only, echocardiography revealed diffuse hypokinesis with an ejection fraction estimated at 15-20%, and troponins peaked at greater than 270,000 pg/mL. Due to decreased Glasgow Coma Score and hemodynamic instability, the patient was not taken for cardiac catheterization, but was subsequently sedated, intubated, and placed on pressor support in the ICU. Initial brain imaging was negative for acute intracranial process but repeat head CT on day four of hospitalization showed diffuse cerebral edema and anoxic brain injury. At the request of the family, he remained on ventilator and hemodynamic support until a nuclear perfusion scan confirmed anoxic encephalopathy. He died within five minutes of extubation on day ten of his hospital stay

Volcanic or Fluvial Channels on Ascraeus Mons: Focus on the Source Area of Sinuous Channels on the Southeast Rift Apron

Deciphering the Mars water history is important to understanding the planet's geological evolution and whether it could have sustained life. Channel features on Mars, such as the features documented in Kasei Valles, are generally accepted as evidence for water flowing over the Mars surface in the past [1]. However, not all channels are the product of fluvial processes and many can be interpreted as having a volcanic origin [2]. This research involves studying channel features on the flanks of the Ascraeus Mons volcano, which is a part of the Tharsis province. Numerous sinuous channels exist on the rift apron of Ascraeus Mons and they have been interpreted as either fluvial [3] or volcanic [4,5]. The channels originate from pits and linear depressions and extend for many 100 s of km downslope. Mapping the proximal to distal morphology of the complete channel and determining its relationship with other features on the apron provides evidence for the processes of formation and their relative temporal relationships. This study focused on sinuous channels located on the south-east part of the Ascraeus rift apron (Fig. 1). Observations of possible analogous features on Hawaii are used to provide insights into the processes of formation of the Mars features

Ariel - Volume 10 Number 5

Executive Editors Madalyn Schaefgen David Reich Business Manager David Reich News Editors Medical College Edward Zurad CAHS John Guardiani World Mark Zwanger Features Editors Meg Trexler Jim O\u27Brien Editorials Editor Jeffrey Banyas Photography and Sports Editor Stuart Singer Commons Editor Brenda Peterso

Diseño, síntesis y caracterización de nanomateriales mesoestructurados con catalizadores bioinspirados en metaloenzimas.

En este trabajo centramos nuestro estudio en la síntesis y caracterización de materiales mesoestructurados como son las sílicas mesoporosas. Estos materiales tienen superficies modificables con gran afinidad permitiendo, asimismo, un diseño adecuado de distintos tipos y tamaños de poros. Se sintetizaron dos tipos de silicas: SBA-15 y MCM-41 a las que se le inmovilizaron complejos de bajo peso molecular que son miméticos de la enzima superóxido dismutasa (SOD), que actúa dismutando el O2•-. Dichos complejos dinucleares de Cu2 y CuZn, fueron sintetizados y caracterizados previamente mostrando actividad catalítica. El objetivo de la inmovilización de los complejos fue proporcionarles ventajas como ser: mayor superficie de contacto; parámetros geométricos controlables y comprobar si mejora la estabilidad química y mecánica luego de ser unidos a las sílicas. La caracterización estructural se realizó a través de diversas técnicas: SEM, TEM, para observar la morfología de los materiales (Figura 1); Adsorción-Desorción de N2 para obtener características texturales de los materiales; TGA para estudiar la estabilidad térmica. También se realizaron medidas de susceptibilidad magnética, EPR, XANES, UV-Vis, IR. Una vez caracterizados los materiales, se evaluó la actividad catalítica de tipo SOD, obteniendo buenos resultadosFil: Patriarca, Matías. Universidad Nacional de RosarioFil: Daier, Verónica. Universidad Nacional de RosarioFil: Signorella, Sandra. Universidad Nacional de Rosari

Origin of Sinuous Channels on the SW Apron of Ascraeus Mons and the Surrounding Plains, Mars

Ascraeus Mons is one of three large shield volcanoes located along a NE-SW trending lineament atop the Tharsis Bulge on Mars. Spacecraft images, beginning with Viking in the 1970 s, revealed that the SW rift apron of Ascraeus Mons is cut by numerous sinuous channels, many of which originate from large, elongated, bowl shaped amphitheaters known as the Ascraeus Chasmata. A number of these channels can be traced onto the flatter plains to the east of the rift apron. These features have been interpreted as either fluvial [1] or volcanic [2] in origin. Most recently, it has been shown that one of the longest channels on the Ascraeus rift apron appears to transition into a roofed-over lava channel or lava tube at its distal end, and thus the entire feature is likely of a volcanic origin [2]. In addition, field observations of recent lava flows on Hawaii have shown that lava is capable of producing features such as the complex braided and anastomosing channels and streamlined islands that are observed in the Ascraeus features [2]

Application of metal complexes as biomimetic catalysts on glycerol oxidation

Two biomimetic complexes were evaluated as catalysts in the H2O2 mediated oxidation of glycerol, namely a peroxidase mimetic Fe(III) protoporphyrin complex (hematin) and the superoxide-dismutase mimetic complex of Mn(III) with 1,3-bis(5-sulphonatesalycilidenamino) propane (MnL−). Catalysis was targeted to glyceraldehyde since antimicrobial power was proved for it. Glyceraldehyde evolved at a higher rate than the uncatalyzed reaction only with hematin acid treated solutions and kinetics were typical of a radical mechanism. Nonetheless, glycerol conversions were low. H2O2 bleached hematin and the immobilization on a porous matrix could not prevent this. Meanwhile, the catalatic activity of hematin was high but its peroxidatic activity was inhibited at pH > 8. Thus, the coordination of hematin compound I to H2O2 over glycerol may be the preferred route with the accumulation of peroxy radicals, able to degrade the porphyrinic ring -with probable iron releasing- but also contributing to glycerol oxidation. On the other hand, a prompt decay with time of the catalatic and peroxidatic activities of MnL− was observed, which was improved by the addition of dimethylsulfoxide (DMSO), dimethylformamide (DMF) or acetone to the basic buffer system. Finally, EPR spectroscopy of MnL− supported the hypothesis of the formation of an inactive bis-oxo-bridged Mn(IV)Mn(IV) dimer upon addition of H2O2.publishedVersionFil: Parodi, Adrián Rodrigo. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada (IPQA); Argentina.Fil: Parodi, Adrián Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada (IPQA); Argentina.Fil: Merlo, Carolina. Universidad Nacional de Córdoba. Instituto Multidisciplinario de Biología Vegetal (IMBIV); Argentina.Fil: Merlo Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Instituto Multidisciplinario de Biología Vegetal (IMBIV); Argentina.Fil: Córdoba, Agostina. Universidad Tecnológica Nacional - Facultad Regional Córdoba (U.T.N – F.R.C). Centro de Investigación y Tecnología Química “Prof. Dr. Oscar A. Orio” (CITeQ); Argentina.Fil: Córdoba, Agostina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro de Investigación y Tecnología Química “Prof. Dr. Oscar A. Orio” (CITeQ); Argentina.Fil: Palopoli, Claudia. Universidad Nacional de Rosario. Instituto de Química Rosario (IQUIR); Argentina.Fil: Palopoli, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro Científico Tecnológico (CCT Rosario). Instituto de Química Rosario (IQUIR); Argentina.Fil: Ferreyra, Joaquín. Universidad Nacional de Rosario. Instituto de Química Rosario (IQUIR); Argentina.Fil: Ferreyra, Joaquín. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro Científico Tecnológico (CCT Rosario). Instituto de Química Rosario (IQUIR); Argentina.Fil: Signorella, Sandra. Universidad Nacional de Rosario. Instituto de Química Rosario (IQUIR); Argentina.Fil: Signorella, Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro Científico Tecnológico (CCT Rosario). Instituto de Química Rosario (IQUIR); Argentina.Fil: Ferreira, María Luján. Universidad Nacional del Sur (UNS). Planta Piloto de Ingeniería Química (PLAPIQUI); Argentina.Fil: Ferreira, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Planta Piloto de Ingeniería Química (PLAPIQUI); Argentina.Fil: Magario, Ivana. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada (IPQA); Argentina.Fil: Magario, Ivana. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada (IPQA); Argentina