Optimizing hot carrier effects in Pt-decorated plasmonic heterostructures.

Hot carrier generation by light in various semiconductors and metallic nanostructures is important for many photocatalytic and photochemical processes, including water and hydrogen splitting. Here, we report on investigations of hot electron generation and extraction from Pt decorated SiO2-Au nanoparticles using the degradation of methylene blue dye as a test-bed. Enhanced catalytic activity was found with an increase of Pt loading on the surface of the heterostructures. The small size of the Au nanoparticles (∼12 nm) decorating the silica nanoparticles reduces hot electron collisions and related thermalization processes, since charge carriers have short paths to the surface where reactions take place and where Pt is situated. The heterostructures exhibit a broad plasmonic resonance in the visible wavelength range from 500 to 700 nm and hot carrier generation predominately takes place under resonant excitation. Electron-microscopy characterization and numerical modelling have allowed the optimization of Pt coverage for hot-electron transfer, consisting of a thin Pt shell covering the Au nanoparticle with Pt nanoparticles additionally placed on top. This geometry provides an increased number of active sites for methylene blue degradation and promotes separation of charge carriers generated by plasmonic excitations in Au. Such SiO2-Au-Pt nanoparticles are attractive for hot-electron production due to the tunability of their plasmonic resonance and enhanced catalytic activity.

Rational design of bimetallic photocatalysts based on plasmonically-derived hot carriers.

Hot carriers generated by plasmonic excitations have recently opened up new avenues in photocatalysis. The transfer of these energetic carriers to adjacent molecules can promote chemical transformations that are important for hydrogen generation by water splitting, CO2 reduction and degradation of organic pollutants. Here, we have developed and optimised a plasmonic hot-carrier catalytic system based on silica nanoparticles decorated with plasmonic gold nanoparticles as a source of hot carriers, equipped with platinum nanoclusters as co-catalyst for the enhancement of hot-carrier extraction. The latter plays a triple role by providing: a surface favourable for molecular adsorption; hot-electron generation near the nanoclusters due to field enhancement effects and electron momentum relaxation facilitating the electron transfer across the metal surface, exactly where molecules are adsorbed. The combination of plasmonic and catalytic metals in nano-heterostructured devices provides a new platform for photocatalytic processes and is of significant interest for future solar-based clean technologies.

Optimization of a myeloid cell transfusion strategy for infected neutropenic hosts.

Although granulocyte transfusion is a logical, therapeutic option for neutropenic patients with refractory infections, significant technical barriers have prevented its widespread use. A novel phagocyte transfusion strategy has been developed based on activation of a human myeloid cell line HL-60. To further define the potential for HL-60 cells to recapitulate white cell transfusions, a shortened duration of activation was evaluated, facile quality control markers were defined, and the impact of low-dose irradiation on cell function was determined. Three days of activation resulted in increased cell viability and in vitro candidacidal capacity but with slightly higher cell replication compared with 7 days of activation. Cell viability and several flow cytometric measurements were accurate, quality control markers for HL-60 activation. In combination with activation, low-dose irradiation abrogated replication while sparing the candidacidal effects of the HL-60 cells. Infusion of irradiated, activated HL-60 cells improved survival of neutropenic, candidemic mice significantly. In summary, activated, irradiated HL-60 cells are microbicidal, have virtually no replicative capacity, and are safe and effective at protecting neutropenic mice against an otherwise 100% fatal candidal infection. With continued development, this strategy to recapitulate neutrophil functions has the potential to serve as an effective alternative to granulocyte transfusions.

Prevalencia de enfermedad arterial periférica con la determinación del índice tobillo-brazo en pacientes con artritis reumatoide / Prevalence of peripheral arterial disease measured with the ankle-arm index in rheumatic patients suffering from rheumatoid arthritis

La enfermedad arterial periférica (EAP) afecta 15-20% de las personas mayores de 70 años. Objetivo: Establecer la prevalencia de enfermedad arterial periférica mediante la determinación del índice tobillo brazo (ITB) en pacientes con Artritis Reumatoide que acuden a la consulta de reumatología, en el Hospital Universitario "Ángel Larralde" Valencia-Venezuela durante el periodo Enero-Abril 2016. Métodos: Estudio descriptivo, transversal y de campo. Se estudiaron 50 pacientes. La recolección de los datos personales y familiares, así como el registro de las medidas antropométricas, se hizo mediante un formulario prediseñado, utilizando una entrevista estructurada. Resultados: El promedio de edad fue de 54,6 ± 11 años, con un rango de 50 a 60 años; predominio del sexo femenino 76%; índice isquémico promedio de 0,74 ± 0,38 siendo normal en 20%, 42% con EAP leve a moderada, 28% con EAP grave y 10% vaso no compresible; la edad sigue siendo el marcador principal de riesgo de EAP. Entre los factores de riesgo cardiovascular (FRCV) modificables la dislipidemia se observó en 38%,obesidad 12%, sedentarismo 100%, consumo de alcohol 2%, tabaquismo 32%, hipertensión arterial 32% y Diabetes Mellitus (DM) 22%. El 74% de los pacientes han utilizado terapia biológica como tratamiento para Artritis Reumatoide dada por Adalimumab/Leflunomida 24%, Metrotrexate/ Etarnecept 10%, Metrotrexate /Adalimumab 8%. Al correlacionar los FRCV no modificables (edad, sexo) y modificables (dislipidemia, obesidad, sedentarismo, consumo de alcohol, tabaquismo, antecedentes de HTA y DM) con el uso de la terapia biológica sólo se observó relación estadísticamente significativa con el tabaquismo (P=0.04) y, con una relación inversa muy baja (-0.293) pero estadísticamente significativa (P=0.039), con el valor bioquímico de la glicemia. Conclusiones: En vista de la poca asociación entre la alteración del ITB con los factores de riesgo cardiovascular, podría plantearse la posibilidad que la Artritis Reumatoide per se sea un factor independiente para desarrollar EAP(AU)

Peripheral arterial disease (PAD) affects 15-20% of people older than 70 years. Objectives: to determine the prevalence of peripheral arterial disease measuring the ankle-brachial index in ambulatory patients who had Rheumatoid Arthritis, at the Hospital Universitario Angel Larralde in Valencia-Venezuela during the period 2015-2016. Methods: This is a descriptive, transversal study, with a sample of 50 patients who attended the rheumatology clinic of the hospital. The collection of personal and family data as well as the registration of anthropometric measurements were done through a pre-designed form with a structured interview. The average age was 54.6 ± 11 years. Results: gender: 76% were female; the average age was between 50 and 60 years, mean 0.74 ± 0.38; the Ischemic index was normal in 20%, 42% had mild to moderate PAD, in 28% it was severe and 10% non compressible. Age remains as the main risk marker for EAP; among the modifiable risk factors, dyslipidemia was observed in 38%, obesity 12%, sedentarism 100%, alcohol consumption 2%, smoking 32%, hypertension 32% and Diabetes Mellitus 22%. 74% of patients had received biological therapy as a treatment for rheumatoid arthritis: Adalimumab / Leflunomide 24%, Metrotrexate / Etarnecept 10%, Metrotrexate / Adalimumab 8%. When correlating non-modifiable CVD (age, sex) and modifiable (dyslipidemia, obesity, sedentary lifestyle, alcohol consumption, smoking, history of hypertension and DM) and use of biological therapy, a statistically significant relationship with smoking (P=0.04), and with a very low inverse (-0.293) statistically significant (P = 0.039) with the biochemical value of glycemia. Conclusions: Rheumatoid Arthritis per se may be an independent factor in the development of PAD. Recommendation: there is a need to routinely perform ABI in patients with asymptomatic RA from a cardiovascular point of view.(AU)

Management of deformational plagiocephaly: repositioning versus orthotic therapy.

OBJECTIVES: We compare positioning with orthotic therapy in 298 consecutive infants referred for correction of head asymmetry. STUDY DESIGN: We evaluated 176 infants treated with repositioning, 159 treated with helmets, and 37 treated with initial repositioning followed by helmet therapy when treatment failed. We compared reductions in diagonal difference (RDD) between repositioning and cranial orthotic therapy. Helmets were routinely used for infants older than 6 months with DD >1 cm. RESULTS: For infants treated with repositioning at a mean age of 4.8 months, the mean RDD was 0.55 cm (from an initial mean DD of 1.05 cm). For infants treated with cranial orthotics at a mean age of 6.6 months, the mean RDD was 0.71 cm (from an initial mean DD of 1.13 cm). CONCLUSIONS: Infants treated with orthotics were older and required a longer length of treatment (4.2 vs 3.5 months). Infants treated with orthosis had a mean final DD closer to the DD in unaffected infants (0.3 +/- 0.1 cm), orthotic therapy was more effective than repositioning (61% decrease versus 52% decrease in DD), and early orthosis was significantly more effective than later orthosis (65% decrease versus 51% decrease in DD).