The Role of Adsorbed and Subsurface Carbon Species for the Selective Alkyne Hydrogenation Over a Pd-Black Catalyst: An Operando Study of Bulk and Surface.

The selective hydrogenation of propyne over a Pd-black model catalyst was investigated under operando conditions at 1 bar making use of advanced X-ray diffraction (bulk sensitive) and photo-electron spectroscopy (surface sensitive) techniques. It was found that the population of subsurface species controls the selective catalytic semi-hydrogenation of propyne to propylene due to the formation of surface and near-surface PdCx that inhibits the participation of more reactive bulk hydrogen in the hydrogenation reaction. However, increasing the partial pressure of hydrogen reduces the population of PdCx with the concomitant formation of a ß-PdHx phase up to the surface, which is accompanied by a lattice expansion, allowing the participation of more active bulk hydrogen which is responsible for the unselective total alkyne hydrogenation. Therefore, controlling the surface and subsurface catalyst chemistry is crucial to control the selective alkyne semi-hydrogenation.

Probing Electron Spin Resonance in Monolayer Graphene.

The precise value of the g factor in graphene is of fundamental interest for all spin-related properties and their application. We investigate monolayer graphene on a Si/SiO_{2} substrate by resistively detected electron spin resonance. Surprisingly, the magnetic moment and corresponding g factor of 1.952±0.002 is insensitive to charge carrier type, concentration, and mobility.

Determinación de la concentración de fosfatos en los colirios antiglaucomatosos comercializados en España / Determination of phosphate concentration in glaucoma eye drops commercially available in Spain

OBJETIVO: Identificar y determinar la concentración de fosfatos en colirios antiglaucomatosos comercializados en España. MATERIAL Y MÉTODO: Se identificaron colirios antiglaucomatosos según Vademecum 2013 y página web de la Agencia Española del Medicamento y Productos Sanitarios. En los que contenían fosfatos según la ficha técnica se determinó la concentración de estos mediante espectrofotometría de absorción molecular basada en radiación ultravioleta y el pH mediante algoritmos de análisis de imagen por escáner a partir de tiras de papel. RESULTADOS: Se registraron 37 colirios antiglaucomatosos con fosfatos. La media de la concentración de fosfatos fue 97,72 ± 75,52 mM. El principio activo con mayor concentración fue timolol (204,85 ± 42,38 mM) seguido de brimonidina/timolol (200,9 mM). No se registraron diferencias estadísticamente significativas entre los colirios de referencia de especialidad (95,65 ± 71,11 mM) y los genéricos (99,14 ± 80 mM; p = 0,892). Tampoco se observaron diferencias entre aquellos con conservantes (99,24 ± 76,78 mM) y sin ellos (85,17 ± 72,86 mM; p = 0,730), aunque los principios de timolol y latanoprost presentaron menos fosfatos en su composición sin conservantes. Las unidosis presentaron menos fosfatos que las multidosis (102,04 ± 75,39 vs. 22,24 ± 2,98 mM; p < 0,001). El pH medio fue 7,13 ± 0,63. No se encontró correlación estadística entre la concentración de fosfatos y el pH (r: 0,07). CONCLUSIONES: La concentración de fosfatos en todos los colirios superaba la concentración fisiológica en la película lagrimal (1,45 mM). No se observaron diferencias en la cantidad de fosfatos entre los medicamentos genéricos y los de referencia de especialidad. Los antiglaucomatosos sin conservantes en unidosis presentaron menos fosfatos

OBJECTIVES: To identify and analyze the phosphate concentration in glaucoma eye drops available in Spain. MATERIAL AND METHODS: Glaucoma medications containing phosphates were identified according to the 2013 Vademecum and the website of the Spanish Agency for Medicines and Medical Devices. Phosphate concentration was determined in these eye drops using ultraviolet molecular absorption spectrophotometry, and pH was determined using scan image analysis algorithms of pH strips. RESULTS: A total of 37 phosphate containing glaucoma eye drops were identified. The mean phosphate concentration was 97.72 ± 75.52 mM. The group with higher concentration of active substance was timolol (204.85 ± 42.38 mM) followed by brimonidine/timolol (200.9 mM). No statistically significant difference was found between brand name (95.65 ± 71.11 mM) and generic eye drops (99.14 ± 80 mM, P = .892). Although no statistically significant difference was found between products containing preservatives (99.24 ± 76.78 mM) and those without preservatives (85.17±72.86mM) (P = .730), a lower phosphate concentration was observed in the preservative-free Timolol and Latanoprost. Single dose samples showed a lower phosphate concentration than multi-dose ones (102.04 ± 75.39 vs. 22.24 ± 2.98 mM, P <.001). The mean pH was 7.13 ± 0.63. No statistical correlation was found between phosphate concentration and pH (r: 0.07). CONCLUSION: The phosphate concentration in glaucoma eye drops exceeded the tear film physiological level (1.45mM). No difference was observed between brand names and generic eye drops. Lower phosphate concentration was observed in preservative-free single dose eye drops

Determinación de la concentración de fosfatos y pH en los colirios de lágrima artificial / Determination of phosphate concentration and pH in artificial tear drops

OBJETIVO: Determinar la concentración de fosfatos y el pH de los colirios de lágrima artificial disponibles comercialmente en España. MATERIAL Y MÉTODOS: Se identificaron 71 lágrimas artificiales según Vademécum 2014 y página web de la Agencia Española del Medicamento y Productos Sanitarios. En las 24 lágrimas cuya ficha técnica indicaba que contenían fosfatos, se determinó la concentración de estos mediante espectrofotometría de absorción molecular basada en radiación ultravioleta y el pH mediante algoritmos de análisis de imagen por escáner a partir de tiras de papel. RESULTADOS: Se identificaron 71 lágrimas artificiales, de las cuales 24 contenían fosfatos entre sus excipientes; en 3 lágrimas la concentración de estos era menor al umbral de detección (< 0,1 mM). La media de la concentración de fosfatos fue 17,91 ± 23,87 mM. La lágrima artificial con mayor concentración fue Colircusi Humectante (87,1mM). Las que contenían hipromelosa como principio activo presentaban las concentraciones más elevadas (41,59 ±32,11 mM), observándose diferencias estadísticamente significativas respecto a povidona (p = 0,0196) e hialuronato (p = 0,0067). También se registraron diferencias estadísticamente significativas entre lágrimas con conservantes (32,39 ± 20,91 mM) y sin ellos (8,49 ± 11,98 mM) (p = 0,0498). Sin embargo, no se observaron entre lágrimas con presentación multidosis (20,21 ±26,91 mM) o monodosis (9,31 ± 14,39 mM) ni entre marcas comerciales (15,44 ±23,3 mM) y genéricos (20,81 mM). La media del pH hallado fue de 6,93 ± 0,26 (6,2-7,22), sin observar una correlación entre este valor y la concentración de fosfatos (Rho de Spearman: −0,1089 con p = 0,6125). CONCLUSIÓN: El 33,8% de las lágrimas contenían fosfatos (24 de 71). Consideramos que conocer la concentración de fosfatos de las lágrimas artificiales es una información útil que nos permitirá evitar complicaciones potencialmente graves en pacientes de riesgo

OBJECTIVE: To determine phosphate concentration and pH in artificial tear eye drops commercially available in Spain. MATERIALS AND METHODS: A total of 71 examples of artificial tear preparations were identified in a search of Vademecum 2014 and the Spanish Medicines Agency website. In the 24 artificial tear products containing phosphates, quantification of these was performed by ultraviolet molecular absorption spectrophotometry, and the determination of pH was performed using scan image analysis algorithms of pH strips. RESULTS: Of the 71 artificial tears tested, 24 contained phosphate among their excipients in the data sheet, three of which had a concentration level below detection limit (<0.1mM). The mean phosphate concentration was 17.91±23.87mM. The artificial tear sample containing a higher concentration was Colircusi Humectante (87.1mM). Lubricants based on hypromellose showed the highest phosphate concentration (41.59±32.1mM), showing statistically significant differences compared to povidone (P = .0196) and hyaluronate (P = .0067). Statistically significant differences were found between products containing preservatives (32.39 ± 20.91 mM), and preservative free ones (8.49±11.98 mM) (P=.0498). However, no difference was found between multidose (20.21 ± 26.91 mM) and unidose (9.31 ±14.39 mM) samples, or between brand name (15.44 ± 23.3 mM) and generic eye drops (20.81 mM). The mean pH was 6.93 ± 0.26 (6.2-7.22). No statistical correlation was detected between phosphate concentration and pH (Spearman's Rho −0.1089 and P = .6125). CONCLUSION: A total of 24 (33.8%) of the 71 artificial tears contained phosphate. We believe identifying the phosphate concentration of artificial tears is useful information in order to avoid complications in high-risk patients

Atmospheric pressure X-ray photoelectron spectroscopy apparatus: Bridging the pressure gap.

One of the main goals in catalysis is the characterization of solid/gas interfaces in a reaction environment. The electronic structure and chemical composition of surfaces become heavily influenced by the surrounding environment. However, the lack of surface sensitive techniques that are able to monitor these modifications under high pressure conditions hinders the understanding of such processes. This limitation is known throughout the community as the "pressure gap." We have developed a novel experimental setup that provides chemical information on a molecular level under atmospheric pressure and in presence of reactive gases and at elevated temperatures. This approach is based on separating the vacuum environment from the high-pressure environment by a silicon nitride grid-that contains an array of micrometer-sized holes-coated with a bilayer of graphene. Using this configuration, we have investigated the local electronic structure of catalysts by means of photoelectron spectroscopy and in presence of gases at 1 atm. The reaction products were monitored online by mass spectrometry and gas chromatography. The successful operation of this setup was demonstrated with three different examples: the oxidation/reduction reaction of iridium (noble metal) and copper (transition metal) nanoparticles and with the hydrogenation of propyne on Pd black catalyst (powder).

Determination of phosphate concentration in glaucoma eye drops commercially available in Spain. / Determinación de la concentración de fosfatos en los colirios antiglaucomatosos comercializados en España.

OBJECTIVES: To identify and analyze the phosphate concentration in glaucoma eye drops available in Spain. MATERIAL AND METHODS: Glaucoma medications containing phosphates were identified according to the 2013 Vademecum and the website of the Spanish Agency for Medicines and Medical Devices. Phosphate concentration was determined in these eye drops using ultraviolet molecular absorption spectrophotometry, and pH was determined using scan image analysis algorithms of pH strips. RESULTS: A total of 37 phosphate containing glaucoma eye drops were identified. The mean phosphate concentration was 97.72±75.52mM. The group with higher concentration of active substance was timolol (204.85±42.38mM) followed by brimonidine/timolol (200.9mM). No statistically significant difference was found between brand name (95.65±71.11mM) and generic eye drops (99.14±80mM, P=.892). Although no statistically significant difference was found between products containing preservatives (99.24±76.78mM) and those without preservatives (85.17±72.86mM) (P=.730), a lower phosphate concentration was observed in the preservative-free Timolol and Latanoprost. Single dose samples showed a lower phosphate concentration than multi-dose ones (102.04±75.39 vs. 22.24±2.98mM, P<.001). The mean pH was 7.13±0.63. No statistical correlation was found between phosphate concentration and pH (r: 0.07). CONCLUSION: The phosphate concentration in glaucoma eye drops exceeded the tear film physiological level (1.45mM). No difference was observed between brand names and generic eye drops. Lower phosphate concentration was observed in preservative-free single dose eye drops.

Determination of phosphate concentration and pH in artificial tear drops. / Determinación de la concentración de fosfatos y pH en los colirios de lágrima artificial.

OBJECTIVE: To determine phosphate concentration and pH in artificial tear eye drops commercially available in Spain. MATERIALS AND METHODS: A total of 71 examples of artificial tear preparations were identified in a search of Vademecum 2014 and the Spanish Medicines Agency website. In the 24 artificial tear products containing phosphates, quantification of these was performed by ultraviolet molecular absorption spectrophotometry, and the determination of pH was performed using scan image analysis algorithms of pH strips. RESULTS: Of the 71 artificial tears tested, 24 contained phosphate among their excipients in the data sheet, three of which had a concentration level below detection limit (<0.1mM). The mean phosphate concentration was 17.91±23.87mM. The artificial tear sample containing a higher concentration was Colircusi Humectante (87.1mM). Lubricants based on hypromellose showed the highest phosphate concentration (41.59±32.1mM), showing statistically significant differences compared to povidone (P=.0196) and hyaluronate (P=.0067). Statistically significant differences were found between products containing preservatives (32.39±20.91mM), and preservative free ones (8.49±11.98mM) (P=.0498). However, no difference was found between multidose (20.21±26.91mM) and unidose (9.31±14.39mM) samples, or between brand name (15.44±23.3mM) and generic eye drops (20.81mM). The mean pH was 6.93±0.26 (6.2-7.22). No statistical correlation was detected between phosphate concentration and pH (Spearman's Rho -0.1089 and P=.6125). CONCLUSION: A total of 24 (33.8%) of the 71 artificial tears contained phosphate. We believe identifying the phosphate concentration of artificial tears is useful information in order to avoid complications in high-risk patients.

Controlling graphene plasmons with resonant metal antennas and spatial conductivity patterns.

Graphene plasmons promise unique possibilities for controlling light in nanoscale devices and for merging optics with electronics. We developed a versatile platform technology based on resonant optical antennas and conductivity patterns for launching and control of propagating graphene plasmons, an essential step for the development of graphene plasmonic circuits. We launched and focused infrared graphene plasmons with geometrically tailored antennas and observed how they refracted when passing through a two-dimensional conductivity pattern, here a prism-shaped bilayer. To that end, we directly mapped the graphene plasmon wavefronts by means of an imaging method that will be useful in testing future design concepts for nanoscale graphene plasmonic circuits and devices.

[Bilateral posterior scleritis]. / Escleritis posterior bilateral.

Posterior scleritis is an inflammatory process of the posterior part of the sclera. Its prevalence is very low and its diagnosis can be complicated due to the absence of external ocular signs. It is more frequent in women. In young patients it does not usually have other associated pathologies, but in those over 55 years nearly one-third of the cases have a relation with some systemic disease, above all rheumatoid arthritis. The diagnosis of this pathology can require a multidisciplinary approach and the collaboration of ophthalmologists with neurologists, internists or rheumatologists. This article describes a case of idiopathic bilateral posterior scleritis.

Escleritis posterior bilateral / Bilateral posterior scleritis

La escleritis posterior es un proceso inflamatoriode la parte posterior de la esclera. Su prevalencia esmuy baja y el diagnóstico puede resultar complicadopor la ausencia de signos oculares externos. Es más frecuenteen mujeres. Cuando aparece en pacientes jóvenesno suele tener otras patologías asociadas, pero enmayores de 55 años hasta un tercio de los casos tienenrelación con alguna enfermedad sistémica, sobre todola artritis reumatoide. El diagnóstico de esta patologíapuede requerir un abordaje multidisciplinar y la colaboraciónde oftalmólogos con neurólogos, internistas oreumatólogos. En este artículo se describe un caso deescleritis posterior bilateral idiopática (AU)

Posterior scleritis is an inflammatory process ofthe posterior part of the sclera. Its prevalence is verylow and its diagnosis can be complicated due to theabsence of external ocular signs. It is more frequentin women. In young patients it does not usually haveother associated pathologies, but in those over 55 yearsnearly one-third of the cases have a relation with somesystemic disease, above all rheumatoid arthritis. Thediagnosis of this pathology can require a multidisciplinaryapproach and the collaboration of ophthalmologistswith neurologists, internists or rheumatologists.This article describes a case of idiopathic bilateral posteriorscleritis (AU)

[Ophthalmological manifestations of arterial hypertension]. / Manifestaciones oftalmológicas de la hipertensión arterial.

Systemic Arterial hypertension (AHT) is one of the most frequent diseases in the industrialised countries, with an incidence reaching 30%, a figure that is rising due to the greater life expectancy of the population. This rise in arterial tension causes, or accelerates, changes in the vascular wall of the target organs such as the kidney, brain, heart and eye. At the ocular level, AHT produces lesions in the retina, the choroids and optic nerve head; this can include a wide range of lesions, from slight vascular narrowing to severe visual loss due to ischaemic optical neuropathy. The primary response of the retinal arteries to systemic arterial hypertension is vascular narrowing and the manifestations that appear at the back of the eye in hypertensive retinopathy are diffuse or focal vasoconstriction, extravasation due to increased vascular permeability and arteriosclerosis with swelling of the wall of the vessels. These three entities are responsible for the appearance of different lesions that characterise the stages of the retinal disease, which are: arteriovenous crossings, hard and cotton-like exudates, thrombosis, embolisms, haemorrhages in the retinal parenchyma, vitreous detachment from the retina, papilla edema and ischaemic optical neuropathy in the more severe cases, such as in case malign arterial hypertension.

Manifestaciones oftalmológicas de la hipertensión arterial / Ophthalmological manifestations of arterial hypertension

La hipertensión arterial sistémica (HTA) es una delas enfermedades más frecuentes en los países industrializados,llegando su incidencia hasta un 30%, cifraque va en aumento por la mayor esperanza de vida dela población. Esta elevación de la presión arterial ocasionao acelera los cambios en la pared vascular de losórganos diana como el riñón, cerebro, corazón y ojo.A nivel ocular, la HTA produce lesiones en la retina,la coroides y cabeza del nervio óptico, pudiendoabarcar un amplio rango de lesiones, desde un estrechamientovascular leve hasta una pérdida visual severapor neuropatía óptica isquémica.La respuesta primaria de las arterias retinianas ala hipertensión arterial sistémica es un estrechamientovascular y los signos que aparecen en el fondo de ojoen la retinopatía hipertensiva son la vasoconstriccióndifusa o focal, la extravasación por permeabilidad vascularaumentada y la arteriolosclerosis con engrosamientode la pared de los vasos. Estas tres entidadesson las responsables de la aparición de diferenteslesiones que van a caracterizar los estadíos de la enfermedadretiniana como son: los cruces arteriovenosos,exudados duros y algodonosos, trombosis, embolias,hemorragias en el parénquima retiniano, desprendimientoseroso de retina, edema de papila y neuropatíaóptica isquémica en los casos más severos como elcaso de la hipertensión arterial maligna

Hipoglucemia por hiperinsulinismo endógeno autoinmune. A propósito de un caso y revisión de la bibliografía / Hypoglycemia due to endogenous hyperinsulinism. Case report and review of the literature

La hipoglucemia por hiperinsulinismo endógeno tiene su origen principal en los tumores pancreáticos y extrapancreáticos. En los últimos años asistimos al incremento de las causas autoinmunes, cuya etiología reconoce la presencia de anticuerpos específicos dirigidos contra la insulina, su receptor, e incluso la propia célula beta. Son producidos en el curso de otras enfermedades autoinmunes y están relacionados con las mismas y/o con fármacos empleados en su tratamiento (destacando aquellos que contienen el grupo sulfidrilo), que alterarían de algún modo la molécula de insulina confiriéndole mayor inmunogenicidad y disminuyendo, a la vez, su actividad biológica. El escaso número de publicaciones en la bibliografía mundial, y el hecho de que la gran mayoría se haya descrito en razas orientales, así como su fuerte correlación con determinado sistema HLA, sugieren la existencia de un componente genético predisponente. Describimos un caso de hipoglucemia por hiperinsulinismo endógeno, en el que descartamos origen tumoral y hallamos valores elevados de insulina y péptido C junto con una alta tasa de anticuerpos antiinsulina, coincidiendo con el tratamiento con metimazol para una enfermedad de Graves, cuadro que mejora espontáneamente y desaparece tras suprimir el fármaco. Aunque coincide con el cuadro de síndrome autoinmune de insulina descrito inicialmente por Hirata, existen particularidades que le confieren especial interés: por una parte, la etnia y un sistema HLA diferente del referido por dicho autor; por otra, una tasa de insulina libre muy elevada si la comparamos con la hallada en la mayoría de los casos y, por último, la coexistencia de anticuerpos anti-GAD que permanecen positivos tras la normalización de los parámetros clínicos y biológicos, y que sugieren la posibilidad de aparición futura de una (AU)