Escaping undesired gas-phase chemistry: Microwave-driven selectivity enhancement in heterogeneous catalytic reactors.

Research in solid-gas heterogeneous catalytic processes is typically aimed toward optimization of catalyst composition to achieve a higher conversion and, especially, a higher selectivity. However, even with the most selective catalysts, an upper limit is found: Above a certain temperature, gas-phase reactions become important and their effects cannot be neglected. Here, we apply a microwave field to a catalyst-support ensemble capable of direct microwave heating (MWH). We have taken extra precautions to ensure that (i) the solid phase is free from significant hot spots and (ii) an accurate estimation of both solid and gas temperatures is obtained. MWH allows operating with a catalyst that is significantly hotter than the surrounding gas, achieving a high conversion on the catalyst while reducing undesired homogeneous reactions. We demonstrate the concept with the CO2-mediated oxidative dehydrogenation of isobutane, but it can be applied to any system with significant undesired homogeneous contributions.

Photolithographic nanoseeding method for selective synthesis of metal-catalysed nanostructures.

In this work we present a general method for the selective synthesis by photolithography of localised nanostructures in planar geometries. The methodology relies on the previous concept of photo-patternable metallic nanoparticle (NP)/polymer nanocomposites, which can provide a range of NP sizes, polydispersity and densities. First, a photoresist containing metallic ions is patterned by photolithography. Silver NPs are synthesised in situ after the exposure and development of the patterned thin film via the thermal-induced reduction of ions embedded in its structure. Gentle plasma ashing is used to selectively remove the polymer, which leaves NPs on the patterned areas. These NPs are used as seeds for subsequent processes. In order to demonstrate the flexibility of the method, its use to selectively produce localised nanostructures through different processes is shown here. Following a top-down approach, high aspect-ratio silicon nanograss has been produced by reactive ion etching and masking by the NPs. In a bottom-up approach, 280 nm copper clusters have been selectively grown in arrays. This method can be easily extrapolated to other metals and it provides a quick way to selectively generate hierarchical nanostructures in large planar areas that can be used for different applications, such as the fabrication of nanostructured sensor arrays.

Evolución de la cultura de seguridad del paciente en un hospital de media-larga estancia: indicadores de seguimiento / Evolution of patient safety culture in a medium-stay hospital: monitoring indicators

Fundamento: La seguridad del paciente es un reto para la asistencia sanitaria. El objetivo de este estudio es identificar las dimensiones con mayor impacto sobre la cultura de seguridad en un hospital de media-larga estancia, monitorizar su evolución y comprobar la sensibilidad de los indicadores de seguimiento. Material y métodos: Se realizaron 2 estudios transversales (2013-2015), utilizando la versión española del cuestionario «Hospital Survey on Patient Safety» (AHRQ). Variable resultado: alto grado de seguridad percibida (puntuación ≥ al percentil 75). Variables predictoras: características socio-demográficas y percepciones de las dimensiones evaluadas. La asociación entre variables se cuantificó mediante OddsRatio. Resultados: El grado de seguridad percibida fue similar en ambos estudios: (7,81-7,48; N2013=66; N2015=92). Los aspectos mejor evaluados fueron: «Acciones de los supervisores» y «Trabajo en equipo en la unidad»; los peor evaluados fueron: «Dotación de personal», «Apoyo de la dirección» y «Trabajo en equipo entre unidades». Las variables socio-demográficas presentaron escasa significación, mientras que una percepción positiva de algunas dimensiones consideradas, sí que se asociaba a un alto grado de seguridad percibida. Los aspectos más fuertemente asociados fueron: «Acciones de los supervisores», «Franqueza en la comunicación» y «Problemas en los cambios de turno». En el estudio comparativo de los resultados, los indicadores basados en las dimensiones individuales detectaron mejor los cambios que el grado de seguridad percibida. Conclusiones: La evaluación periódica de la cultura de seguridad permite conocer el estado y la evolución de las percepciones de los profesionales. La elección de indicadores apropiados optimiza la información obtenida a través de estas encuestas (AU)

Background: Patient safety is a challenge for health care. The aim of this study is to identify the dimensions with the greatest impact on patient safety culture of healthcare staff in a medium-stay hospital; to asses its evolution over time and to check the sensitivity of monitoring indicators. Methods: Two cross-sectional studies (2013 to 2015) were conducted. The safety culture assessment tool used was the Spanish version of the «Hospital Survey on Patient Safety» (AHRQ). Outcome variable is high perception of safety (score ≥ 75th percentile). Independent variables: socio-demographic characteristics and perceptions of the evaluated dimensions. The association between variables was quantified by Odds Ratio. Results: The mean of perceived safety was similar in both studies: (7.81 and 7.48, N2013= 66; N2015=92). The best aspects evaluated were: «Supervisor actions» and «Teamwork within unit»; the worst evaluated were: «Staffing», «Management support» and «Teamwork across units». Socio-demographic variables had little significance, while a positive perception in some of the considered dimensions was associated with high perceived safety. The most strongly associated aspects were: «Supervisor actions», «Communication openness» and «Problems in transitions». In the comparative study, indicators based on individual dimensions detected changes better than the assessment of the degree of perceived safety. Conclusion: The regular assessment of Patient Safety Culture makes it possible to know the status and evolution of professionals' perceptions. The choice of appropriate indicators optimises the information obtained through these surveys (AU)

Titania-coated gold nanorods with expanded photocatalytic response. Enzyme-like glucose oxidation under near-infrared illumination.

Gold nanorods coated with a uniform titanium dioxide nanoshell have been prepared and used as glucose-oxidase surrogates. Remarkably, this core-shell photocatalytic nanostructure has been able to induce complete oxidation of glucose at near room temperature (32-34 °C) in a wide range of pH values with the aid of a near-infrared (NIR) irradiation source. In contrast, the uncoated gold nanorods exhibit negligible photo-oxidation response under identical experimental conditions thereby proving the photoactivity of the titania shell towards glucose oxidation. The process takes place via in situ photo-generation of singlet oxygen or hydroxyl radicals as reactive oxidative species (ROS). This underlines the role played by the core nanorods as plasmonic light harvesters in the NIR range and constitutes the first example of a NIR-activated enzyme-like catalyst.

Feroxyhyte nanoflakes coupled to up-converting carbon nanodots: a highly active, magnetically recoverable, Fenton-like photocatalyst in the visible-NIR range.

We demonstrate the enhanced photocatalytic response of a novel Fenton-like heterogeneous catalyst obtained through the assembly of superparamagnetic feroxyhyte nanoflakes synthesized by continuous gas-slug microfluidics and carbon nanodots obtained by pyrolysis from a natural organic source. The novel nanohybrids enable the utilization of the visible and near-infrared ranges due to the active role of the carbon nanodots as up-converting photo-sensitizers. This novel photocatalyst is magnetically recoverable and maintains an excellent response after multiple reutilization cycles. In addition, its synthesis is based on inexpensive and abundant raw materials and its photocatalytic response is evaluated in the presence of energy efficient, affordable light-emitting diodes (LEDs), thereby providing a promising and feasible alternative to the homogeneous Fenton process.

Facile production of stable silicon nanoparticles: laser chemistry coupled to in situ stabilization via room temperature hydrosilylation.

Stable, alkyl-terminated, light-emitting silicon nanoparticles have been synthesized in a continuous process by laser pyrolysis of a liquid trialkyl-silane precursor selected as a safer alternative to gas silane (SiH4). Stabilization was achieved by in situ reaction using a liquid collection system instead of the usual solid state filtration. The alkene contained in the collection liquid (1-dodecene) reacted with the newly formed silicon nanoparticles in an unusual room-temperature hydrosilylation process. It was achieved by the presence of fluoride species, also produced during laser pyrolysis from the decomposition of sulfur hexafluoride (SF6) selected as a laser sensitizer. This process directly rendered alkyl-passivated silicon nanoparticles with consistent morphology and size (<3 nm), avoiding the use of costly post-synthetic treatments.

Continuous production of iron-based nanocrystals by laser pyrolysis. Effect of operating variables on size, composition and magnetic response.

Well dispersed iron-based magnetic nanoparticles have been prepared by gas phase laser-driven decomposition of iron pentacarbonyl. Agglomeration of the newly synthesized nanoparticles could be avoided by using a liquid collection system in which the exit stream from the laser reactor was bubbled through triethylene glycol (TREG). The effect of different experimental parameters (precursor concentration, laser power, working pressure, residence time) was studied and, by selecting the appropriate conditions, the size of the resulting magnetic nanocrystals could be tuned from ultrasmall (ca. 2.5 nm) to around 12 nm. For nanoparticle sizes around 10 nm and larger a metallic iron core could be preserved. These iron/iron oxide core-shell compositions exhibit very high values of magnetization, 127 emu g(-1).

Use of a polyol liquid collection medium to obtain ultrasmall magnetic nanoparticles by laser pyrolysis.

The present work addresses the main bottleneck in the synthesis of magnetic nanoparticles by laser pyrolysis. Since the introduction of laser pyrolysis for the production of nanoparticles nearly three decades ago, this method has been repeatedly presented as a highly promising alternative, on account of two main characteristics: (i) its flexibility, since nanoparticles can be formed from a wide variety of precursors in both gas and liquid phase, and (ii) its continuous nature, avoiding the intrinsic variability of batch processing. However, the results reported to date invariably show considerable aggregation of the obtained nanoparticles, which strongly limits their application in most fields. In this work, we have been able to circumvent this problem by collecting the particles in a polyol liquid medium. This method prevents the formation of aggregates and renders a uniform distribution of well dispersed ultrasmall nanoparticles (<4 nm) in a water-compatible solvent. We consider that the effectiveness of this novel collection method for the production of well-dispersed magnetic nanoparticles will be of high interest to a wide range of scientists working in the nanoparticle synthesis field and may enable new applications wherever there is a strict requirement for non-agglomerated nanoparticles.

High-resolution electron-beam patternable nanocomposite containing metal nanoparticles for plasmonics.

Polymer nanocomposites containing noble metal nanoparticles are promising materials for plasmonic applications. In this paper, we report on a high-resolution negative-tone nanocomposite resist based on poly(vinyl alcohol) where silver nanoparticles and nanopatterns are simultaneously generated by electron-beam lithography. Our results indicate nanostructures with a relatively high concentration of nanoparticles and, consequently, an electromagnetic coupling among the nanoparticles. Therefore, the patternable nanocomposite described in this work may be a suitable material for future plasmonic circuitry.

Fast microscopic method for large scale determination of structure, morphology, and quality of thin colloidal crystals.

We present a novel fast microscopic method to analyze the crystal structures of air-dried or suspended colloidal multilayer systems. Once typical lattice spacings of such films are in the range of visible light, characteristic Bragg scattering patterns are observed. If in microscopic observations these are excluded from image construction, a unique color coding for regions of different structures, morphologies, and layer numbers results. Incoherently scattering defect structures, however, may not be excluded from image construction and thus remain visible with high resolution.

Classification and scoring systems in myelodysplastic syndromes: a retrospective analysis of 311 patients.

The main objective of this study was to evaluate the role of the recent World Health Organization (WHO) classification for assessing prognosis in patients with myelodysplastic syndromes (MDS). To this effect, we analyzed the prognostic impact of the WHO and French-American-British (FAB) morphologic classifications and of four different scoring systems in a series of 311 patients with primary MDS diagnosed between October 1990 and June 2001. Both the FAB and WHO classifications identified groups with different prognoses (p<0.0001), those presenting refractory anemia (RA) and refractory anemia with ringed sideroblasts (RARS) showing the best prognosis. The WHO classification subdivided RA into RA with only red cell dysplasia, and refractory cytopenia with multilineage dysplasia (RCMD), and RARS into RARS plus refractory cytopenia with multilineage dysplasia and ringed sideroblast (RCMD-RS). In our population, we have shown that the two subtypes characterized by dysplasia affecting exclusively the erythroid population (RA and RARS) have a better prognosis, with a median survival of 122.2 and 81.9 months, respectively, than those with multilineage dysplasia (RCMD and RCMD-RS) with a median survival of 32.3 and 43.2 months, respectively. There were no significant differences in median survival comparing RA with RAS (p<0.95), or comparing RCMD with RSCMD (p<0.97). Besides, the four scoring systems discriminated our MDS patients in terms of survival, and an increase in prognostic capacity was achieved on adding the score to the morphological classifications. Risk scoring had a greater prognostic impact than the FAB and WHO classifications. Prognostic scoring systems may be an important tool for risk stratification in hematological practice, and add significance to morphological classification. Combined application of the WHO classification and score system is useful for improving the identification of patients with a poorer prognosis. The WHO classification establishes more homogeneous subcategories than the FAB classification and is also able to identify groups with different prognoses.

Plasma chemistry of NO in complex gas mixtures excited with a surfatron launcher.

The plasma chemistry of NO has been investigated in gas mixtures with oxygen and/or hydrocarbon and Ar as carrier gas. Surface wave discharges operating at microwave frequencies have been used for this study. The different plasma reactions have been analyzed for a pressure range between 30 and 75 Torr. Differences in product concentration and/or reaction yields smaller than 10% were found as a function of this parameter. The following gas mixtures have been considered for investigation: Ar/NO, Ar/NO/O2, Ar/NO/CH4, Ar/CH4/O2, Ar/NO/CH4/O2. It is found that NO decomposes into N2 and O2, whereas other products such as CO, H2, and H2O are also formed when CH4 and O2 are present in the reaction mixture. Depending on the working conditions, other minority products such as HCN, CO2, and C2 or higher hydrocarbons have been also detected. The reaction of an Ar/NO plasma with deposits of solid carbon has also been studied. The experiments have provided useful information with respect to the possible removal of soot particles by this type of plasma. It has been shown that carbon deposits are progressively burned off by interaction with the plasma, and practically 100% decomposition of NO was found. Plasma intermediate species have been studied by optical emission spectroscopy (OES). Bands and/or peaks due to N2*, NO*, OH*, C2*, CN*, CH*, or H* were detected with different relative intensities depending on the gas mixture. From the analysis of both the reaction products and efficiency and the type of intermediate species detected by OES, different plasma reactions and processes are proposed to describe the plasma chemistry of NO in each particular mixture of gases. The results obtained provide interesting insights about the plasma removal of NO in real gas exhausts.

SB-253514 and analogues; novel inhibitors of lipoprotein-associated phospholipase A2 produced by Pseudomonas fluorescens DSM 11579. I. Fermentation of producing strain, isolation and biological activity.

Two new classes of inhibitors of LpPLA2 have been identified in fermentations of Pseudomonas fluorescens. The two structurally isomeric series differ in the geometry of closure of the bicyclic carbamate and comprise a range of compounds varying only in length of their lipophilic sidechain. The most abundant species were extracted from the cells and purified by silica and C18 chromatography. Members of the more stable class were shown to be potent and selective competitive inhibitors of LpPLA2.

SB-253514 and analogues: novel inhibitors of lipoprotein associated phospholipase A2 produced by Pseudomonas fluorescens DSM 11579. II. Physico-chemical properties and structure elucidation.

A series of novel inhibitors of lipoprotein associated phospholipase A2 were isolated from the culture broths of Pseudomonas fluorescens strain DSM11579. The inhibitors fall into two structurally isomeric classes each of which comprise compounds incorporating glycosylated hydrocarbon chains. The structure elucidation for the major member of each structural class is reported. The crystal structure of a non-glycosylated analogue of the 5,5-series, produced through biotransformation, is also reported.

Induced endothelial cell loss in phacoemulsification using topical anesthesia plus intracameral lidocaine.

PURPOSE: To determine whether lidocaine 1% injected into the anterior chamber during phacoemulsification damaged the corneal endothelium. SETTING: Ophthalmology Service, University Hospital, San Juan de Alicante, Spain. METHODS: In 19 eyes of 19 patients, small incision phacoemulsification and foldable lens (AcrySof MA60BM) implantation was performed using topical anesthesia supplemented by lidocaine 1% (0.3 mL) in the anterior chamber. All cases were operated by the same surgeon. Specular microscopy was performed before surgery and 1 and 3 months postoperatively. RESULTS: Mean endothelial cell loss was 5.41% +/- 8.50 (SD) at 1 month and 5.93 +/- 8.50% at 3 months. CONCLUSIONS: The endothelial damage was similar to that described by other authors, suggesting that phacoemulsification surgery can be performed successfully using topical anesthesia supplemented by lidocaine 1% in the anterior chamber.

Metallic fragment deposits during phacoemulsification.

PURPOSE: To describe the nature and origin of foreign metallic intraocular bodies appearing after phacoemulsification. SETTING: Department of Ophthalmology, University Hospital of San Juan, Alicante, Spain. METHODS: Two metallic particles, 1 extracted during surgery and the other from a patient in whom surgery had been performed, were studied by scanning electronic microscopy and X-ray dispersive energy spectroscopy. Also evaluated were all metallic elements used in phacoemulsification including phaco tips, Sinskey hooks, and handpieces. A morphologic analysis at various magnifications was performed and the composition of the elements studied. RESULTS: Scanning electronic microscopy showed irregularities of the phaco tip and Sinskey hook after their use. Spectrographic analysis found that the phaco tip was mainly aluminum and titanium; the Sinskey hook, iron, chromium, cobalt, and nickel; the handpiece, iron, chromium, and nickel; and the 2 metallic particles, iron, chromium, and nickel, the same as the handpiece. CONCLUSION: The metallic particles extracted corresponded to those of the phaco handpiece. Vibration during prolonged use of the phacoemulsifier probably caused these particles to chip off the handpiece.

Clinical results of AcrySof intraocular lens implantation.

PURPOSE: To analyze the clinical results of AcrySof intraocular lens (IOL) implantation. SETTING: San Juan University Hospital, Alicante, Spain. METHODS: This retrospective study comprised 100 patients with cataract 81 without previous eye pathology and 19 with previous eye pathology (i.e., diabetes, traumatic cataract, central corneal leukoma, glaucoma). Phacoemulsification technique depended on the type of cataract. Mean follow-up was 9 months. RESULTS: Best corrected visual acuity was 20/40 or better in 11.52% of patients with preoperative eye pathology and in 100% of those without pathology. CONCLUSION: Implantation of AcrySof IOLs did not result in complications or adverse reactions in our series, indicating that its use is safe in small incision cataract surgery.

Long-term results of surgical treatment of high myopia with Worst-Fechner intraocular lenses.

This retrospective study evaluated the results in 90 eyes that had a minuspower anterior chamber intraocular lens implanted to correct high myopia. Preoperative myopia ranged from -7.00 to -24.00 D. Postoperative spherical equivalent was -0.50 D; 80.5% of eyes were within 1.00 D of emmetropia. Two years postoperatively, no cataract formation, retinal detachment, glaucoma, or significant endothelial damage had occurred. We conclude that minus-power lenses can rapidly, safely, and predictably correct high myopia in phakic patients.

[Comparative study between thiopental and propofol in short-duration anesthesia]. / Estudio comparativo entre tiopental y propofol en anestesias de corta duración.

In a randomized study, 80 healthy unpremedicated female patients were included. For short gynaecological procedures (curettage) they were anaesthetized with either propofol 2 mg/kg (n = 40) or thiopentone 5 mg/kg (n = 40) in combination with nitrous oxide/oxygen (1/1). Supplementary doses of propofol (25 mg) or thiopentone (50 mg) were given when necessary during the procedure. Propofol caused a significant fall in arterial blood pressure (greater than thiopentone in diastolic pressure) and a decrease in heart rate (thiopentone did not change heart rate). Discomfort on injection was similar in both groups. Recovery times were shorter in propofol group: Patients opened their eyes at 1.3 minutes, were awake at 2.2 minutes and could seat with no help at 5.2 minutes. In the thiopentone group, there was a greater incidence of nausea. Propofol was associated with euphoria, "clear-headedness" and pleasant dreams more than thiopentone. We conclude that propofol is a good alternative to thiopentone in short operative procedures.