The Conditions Needed for a Buffer to Set the pH in a System

It is a known fact that buffer systems are widely used in industry and in diverse laboratories to maintain the pH of a system within desired limits, occasionally narrow. Hence, the aim of the present work is to study the buffer capacity and buffer efficacy in order to determine the useful conditions to impose the pH on a given system. This study is based on the electroneutrality and component balance equations for a mixture of protons polyreceptors. The added volume equations were established, V, for strong acids or bases, as well as the buffer capacity equations with dilution effect, β dil, and the buffer efficacy, ε, considering that the analyte contains a mixture of the species of the same polyacid system or of various polyacid systems. The ε index is introduced to define the performance of a buffer solution and to find out for certain, whether the buffer is adequate or not to set the pH of a system, given the proper conditions and characteristics

DEVELOPMENT OF A SECOND TYPE ELECTRODE BASED ON THE SILVER/SILVER IBUPROFENATE PAIR FOR IBUPROFEN QUANTIFICATION IN PHARMACEUTICAL SAMPLES

Ibuprofen is a widely used pharmaceutical because of its therapeutic properties; it is considered a safe medicament, thus it does not require medical prescription to be sold. However, in order to ensure consumer's health it is indispensable that the pharmaceutical industry relies on analytic methods for its quantification. Potentiometry has proven to be a successful technique using second type electrodes, which in agreement with Nernst's equation can detect anions activity. On consideration of this, this research work presents the development of a second type electrode based on the silver/silver ibuprofenate pair. This involved modifying a pure silver wire using a sodium ibuprofenate solution, to obtain the redox pair. The following analytic parameters were obtained with the aid of the modified electrode: a sensitivity of -0.049 V decade [ibuprofenate]-1, 8 µmol L-1 for the detection limit and a quantification limit of 1.2 µmol L-1. The repeatability value in terms of the relative standard deviation was 5.9%. After performing an interferences analysis using some ions and excipients, it was corroborated that there were none, thus allowing appropriate quantification on a real sample

Nurses' and Nursing Students' Knowledge and Attitudes regarding Pediatric Pain

Nursing staff spend more time with patients with pain than any other health staff member. For this reason, the nurse must possess the basic knowledge to identify the presence of pain in patients, to measure its intensity and make the steps necessary for treatment. Therefore, a prospective, descriptive, analytical, and cross-sectional study was conducted to investigate the knowledge and attitudes regarding pediatric pain in two different populations. The questionnaire, Pediatric Nurses Knowledge and Attitudes Survey Regarding Pain (PKNAS), was applied to 111 hospital pediatric nurses and 300 university nursing students. The final scores for pediatric nurses and nursing students were 40.1 ± 7.9 and 40.3 ± 7.5, respectively. None of the sociodemographic variables predicted the scores obtained by the participants ( > 0.05). There was a high correlation between the PKNAS scores of pediatric nurses and nursing students ( = 0.86, < 0.001). It was observed that the degree of knowledge about pain and its treatment was very low in both groups. Due to this deficiency, pain in children remains inadequately managed, which leads to suffering in this population. It is necessary to increase the continued training in this subject in both areas

Nurses’ and Nursing Students’ Knowledge and Attitudes regarding Pediatric Pain

Nursing staff spend more time with patients with pain than any other health staff member. For this reason, the nurse must possess the basic knowledge to identify the presence of pain in patients, to measure its intensity and make the steps necessary for treatment. Therefore, a prospective, descriptive, analytical, and cross-sectional study was conducted to investigate the knowledge and attitudes regarding pediatric pain in two different populations. The questionnaire, Pediatric Nurses Knowledge and Attitudes Survey Regarding Pain (PKNAS), was applied to 111 hospital pediatric nurses and 300 university nursing students. The final scores for pediatric nurses and nursing students were 40.1 ± 7.9 and 40.3 ± 7.5, respectively. None of the sociodemographic variables predicted the scores obtained by the participants (P>0.05). There was a high correlation between the PKNAS scores of pediatric nurses and nursing students (r=0.86, P<0.001). It was observed that the degree of knowledge about pain and its treatment was very low in both groups. Due to this deficiency, pain in children remains inadequately managed, which leads to suffering in this population. It is necessary to increase the continued training in this subject in both areas

Synthesis of New 1,2,3-Triazole Derivatives of Uracil and Thymine with Potential Inhibitory Activity against Acidic Corrosion of Steels

molecule

Electrocatalytic performance of palladium-based electrocatalysts supported on carbon nanotubes for formic acid oxidation

In the present work, Pd and PdFe nanoparticles supported on CNT with and without functionalization (CNT and CNTox) were used for Formic Acid Oxidation Reaction (FAOR) in acid media. Electrocatalysts were synthesized by the borohydride reduction method with 20 wt.% metal loading. The CNTs were synthesized by the methane catalytic decomposition, and subjected to an oxidation treatment with nitric acid, named as CNTox. Themorphology, composition and structural properties were studied by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and X-Ray Diffraction (XRD). The FAOR was evaluated in acid media in a conventional three-electrode cell by means of cyclic voltammetry and chronoamperometry. From the steady state current density, it was found that Pd and PdFe supported at CNTox allowed improving the catalytic activity in comparison with the nonoxidized support.Peer reviewe

Catalizadores bimetálicos de PdCo y PdFe para la oxidación electroquímica de ácido fórmico

4 Figuras, 1 Tabla.[EN] Pd, PdCo and PdFe catalysts were prepared by the impregnation method, using sodium borohydride (NaBH4) as the reducing agent and a commercial carbon material (Vulcan XC-72R) as support. The synthesized electrocatalysts were tested for the formic acid oxidation reaction (FAOR) in acid medium (H2SO4 0.5 M). The morphology, composition and particle size of the electrocatalysts were characterized by physicochemical techniques as X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The catalytic activity was evaluated by cyclic voltammetry (CV) and chronoamperometry techniques (CA).[ES] Catalizadores de Pd, PdFe y PdCo fueron preparados por el método de impregnación, usando borohidruro de sodio (NaBH4) como agente reductor y un material de carbono comercial, (Vulcan XC-72R) como soporte. Los electrocatalizadores sintetizados fueron probados para la reacción de oxidación de ácido fórmico (FAOR, por sus siglas en inglés) en medio ácido (H2SO4 0,5 M). La morfología, la composición y el tamaño de partícula de los electrocatalizadores se caracterizaron mediante técnicas físico-químicas como difracción de rayos X (XRD), microscopía electrónica de barrido con espectroscopia por energía dispersiva (SEM-EDS) y microscopia electrónica de transmisión (TEM). La actividad catalítica se evaluó mediante técnicas de voltamperometría cíclica (CV) y cronoamperometría (CA).LJM agradece a CONACyT por la beca otorgada para la realización de los estudios de Maestría, así como a UAM-A, ICB, IPN por el apoyo otorgado para la realización de este trabajo. MGMY, MRR, MEPP y AEM agradecen al SNI. MGMY agradece a L ́oreal-UNESCO-CONACyT-AMC por la beca en Mujeres en la Ciencia 2016. MJL and SPR agradecen al Gobierno de Aragón (DGA) y FEDER por la financiación a través del Grupo de Investigación Conversión de Combustibles (T06_17R)Peer reviewe

Carbon supported PdM (M = Fe, Co) electrocatalysts for formic acid oxidation. Influence of the Fe and Co precursors

8 Figuras.- 4 TablasPd and PdM (M = Fe or Co) nanostructured electrocatalysts were synthesized by the impregnation method and supported on carbon black Vulcan XC-72R for the formic acid oxidation reaction, FAOR, in acid medium. Nitrates or chlorides were used as Fe and Co precursors to study the counter ion role on the physicochemical features and electrochemical performance of the electrocatalysts. TEM analysis showed that PdM was deposited on the carbon material with a particle size around 2–3 nm. From XRD, peaks associated with the fcc palladium planes were observed along with evidence of PdM alloy formation, particularly when the nitrate salts were used as metal precursors. Furthermore, XPS analyses indicated that nitrates promote the metal oxide formation to a greater extent than chlorides, mainly for Pd. PdCo electrocatalyst obtained from nitrates exhibited the highest performance for FAOR with a steady state current density of 451 and 313 μA cm−2 at 200 and 400 mV respectively, which is in both cases, 3 times larger than that developed for a commercial Pd/C catalyst.LJM is grateful to CONACYT for the grant awarded for this research, as well as to the UAM-A and the ICB for the support provided. MGMY, MRR, MPP and AEM thank the SNI for the distinction of their membership and the stipend provided. MGMY is indebted to L'oreál-UNESCO-CONACyT-AMC for the grant Women in Science 2016. MJL and SPR gratefully acknowledge financial support given by Spanish MINECO (ENE2014-52158-C2-1-R).Peer reviewe

Anales de Edafología y Agrobiología Tomo 38 Número 7-8

Suelos Características generales de los suelos fersialíticos de las Islas Canarias, por A. Rodríguez R., M. L. Tejedor S. y E. Fernández.-. Estudio del cambisol Los Labradossobre granito de El Pellroso (Sevilla). II. Mineralogía de las arenas y micromorfología, por L. Corral M., N. Bellinfante C., M. Medina C. y G. Paneque G.-- Nuevos datos sobre la influencia de la vegetación en la formación del suelo en Galicia. I. Interceptación de la precipitación, por R. Mª Calvo de Anta, A. Paz G. y F. Días-Fierros V.-- Las clases y subclases de capacidad de uso de los suelos de Gran Canaria, por J. Sánchez D., A. Guerra D. y E. Fernández C.-- Retención de 1, 3, 5, triazina-2, 4, diamino-6, cloro-N, N', dietilo (Simazina) sobre muestras homoiónicas de montmorillonita y vermiculita y sobre un gel de sílice, por J. de D. López G., C. Valenzuela C. y M. Gaitán P.-- Fósforo orgánico en andosoles y su relación con otros parámetros del suelo, por J. A. Pérez M., F. Gutiérrez J., E. Fernández C. e l. Trujillo J. del Castillo.--Fraccionamiento de los fosfatos orgánicos en andosoles de las Islas Canarias, por F. Gutiérrez J., J. A. Pérez M., E. Fernández C. e l. Trujillo J. del Castillo.-- Fraccionamiento de los fosfatos inorgánicos en anllosoles de las Islas Canarias, por J. A. Pérez M., F. Gutierrez J., F. Fernández C. y A. Borges P.-- Studies on sodium-calcium exchange equilibria. I. In danish soils. l. The Equilibrium activity ratios and the Quantity/Intensity relationships of sodium in marsh soils, by M. H. Nafady.-- Studies on sodium-calcium exchange equilibria. I. In danish soils. 2. The form of sodium exchange isotherm, its properties, and the effect of sorne treatments, by M. H. Nafady.-- El color en los suelos y su posible influencia en la fertilidad del olivo, por C. Siwa, J. Campos, J. Aguilar y M. Delgado.-- Fertilidad de los suelos. Efecto de la adición de caliza sobre el pH y la disponibilidad de elementos de un suelo ácido con especial referencia al fósforo, por E. Vieitez, J. Arines y R. Fábregas. Extracción de hierro activo en suelos calizos con pirofosfato, por M. R. Martínez F., F. G. Fernández, M. Romero y .M. Caro.--Metabolismo fosfórico de Aspergil/us niger en suelos calizos y salinos, por A. Ortuño, Jª Noguera, A. Hernansáez y Tª Armero.-- Acción solubilizadora de fósforo por Aspergillus niger y Pseudomonas fluorescens, por A. Ortuño, A. Hernansáez. J.Noguera, V. Morales y T. Armero.-- Rhizobium meliloti nativo en suelos cultivados con cereales, por M. A. Sagardoy.-- Nitrógeno, fósforo, potasio y elementos menores en los suelos volcánicos del valle de Sibundoy, Colombia, por O. Bastidas, A. Caicedo, F. Romo, M. Villota, M. Blasco y L. Legarda.-- Extracción con ditionito y oxalato de óxidos de hierro libre en suelos calizos y su relación con el extraído con pirofosfato, por M. R. Martínez F., M. Romero, F. G. Fernández y M. Caro.-- Degradación de simazina y atrazina en suelos salinos del Sureste español por A. Ortulio, M. Parra y J. Egea C.-- Isotermas de adsorción de DBCP en suelos, por O. Carpena A., A. Ortuño M., J. M. Abrísqueta G., J. Laencina S. y A. Alonso-Allende Y.--Estudio de la persistencia del nematicida 1,2-dibromo-3-cloropropano (DBCP) y su efectividad sobre Tylenchulus semipenetrans en un suelo citrícola de la vega del Segura, por A. Ortuíio, J. M. Abrisqueta v J. Gómez.-- Contribución al control fitosanitario del Acaro de las Maravillas de los Agrios (Acería sheldoni Ewing), por J. Gómez. A. Ortuño y F. L. Cánovas.-- Estudio de la contaminación de suelos y plantas por metales pesados en los entornos de las autopistas que confluven en Madrid. I. Autopistas de Barajas y Valencia, por J. R. Sanchidrián y M. Mariño.—Nutrición y Fisiología Vegetal.-- Acción del ácido cx-naftalén acético sobre los procesos de histogénesis de tejidos de Heliantltus tuberosus L. yariedad Blanc Sutton cultivados in vitro. I. Neoformación de raíces y organización de zonas generatrices libero-leñosas, por M. J. García R.-- Estudio de las variaciones en el crecimiento de la raíz de guisante nroducidas por tres ácidos húmicos, por C. Ortega, C. Fortún, A. Polo y E. Dorado.-- Variaciones ultraestructurales en Parmelia conspersa S. L. provocadas in vitro por diferentes grados de humedad ambiental , por C. Ascaso.-- Nota previa. Modelación matemática y evaluación agrícola de suelos, por D. de la Rosa y J. Almorza.—Estudios recapitulativos. El Pinus radiata D. Don en Chile. Revisión de las condiciones del cultivo, por C. González 0., R. Kosche P. y M. Lachica. NotasPeer reviewe