Selective Oxidation of Veratryl Alcohol over Au-Pd/Ce0.62Zr0.38O₂ Catalysts Synthesized by Sol-Immobilization: Effect of Au:Pd Molar Ratio

The selective oxidation of veratryl alcohol (VA), a model compound of lignin, with oxygen molecules to produce veratraldehyde (VAld) was studied over monometallic Au, Pd, and bimetallic Au:Pd nanoparticles supported on a Ce0.62Zr0.38O\u2082 mixed oxide for the first time. These bimetallic Au-Pd catalysts with Au:Pd molar ratios from 0.4 to 4.3 were synthesized by the sol-immobilization method. Furthermore, all the catalysts were characterized by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), N\u2082 physisorption, X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy-high angle annular dark field (STEM-HAADF) imaging, energy dispersive X-ray spectroscopy (EDXS), and temperature programmed reduction (TPR) techniques. A synergistic effect between gold and palladium was observed over all the bimetallic catalysts in a wide range of studied Au:Pd ratios. Remarkably, the optimum Au:Pd ratio for this reaction was 1.4 with a turnover frequency of almost six times larger than for the monometallic gold and palladium catalysts. Selectivity to veratraldehyde was higher than 99% for the monometallic Au, Pd, and all the bimetallic Au-Pd catalysts, and stayed constant during the reaction time

The Physical Processes of CME/ICME Evolution

As observed in Thomson-scattered white light, coronal mass ejections (CMEs) are manifest as large-scale expulsions of plasma magnetically driven from the corona in the most energetic eruptions from the Sun. It remains a tantalizing mystery as to how these erupting magnetic fields evolve to form the complex structures we observe in the solar wind at Earth. Here, we strive to provide a fresh perspective on the post-eruption and interplanetary evolution of CMEs, focusing on the physical processes that define the many complex interactions of the ejected plasma with its surroundings as it departs the corona and propagates through the heliosphere. We summarize the ways CMEs and their interplanetary CMEs (ICMEs) are rotated, reconfigured, deformed, deflected, decelerated and disguised during their journey through the solar wind. This study then leads to consideration of how structures originating in coronal eruptions can be connected to their far removed interplanetary counterparts. Given that ICMEs are the drivers of most geomagnetic storms (and the sole driver of extreme storms), this work provides a guide to the processes that must be considered in making space weather forecasts from remote observations of the corona.Peer reviewe

International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

Influence of pretreatment atmospheres on the performance of bimetallic Au-Pd supported on ceria-zirconia mixed oxide catalysts for benzyl alcohol oxidation

Monometallic Au, Pd and bimetallic Au-Pd catalysts supported on a Ce0.62Zr0.38O2 mixed oxide have been synthesized by the sol-immobilization method. An in-depth Scanning-Transmission Electron Microscopy (STEM) study has been performed to reveal the structural and chemical nature of the metal nanoparticle system present in these catalysts. Attention has been paid both to the evolution of the particle size distribution and the degree of Au-Pd interaction as a function of the treatment used to activate the catalysts. This characterization work has been complemented by results coming from other macroscopic techniques like Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), N2 physisorption, Temperature Programmed Oxidation (TPO) or X-ray Photoelectron Spectroscopy (XPS). The whole set of characterization data evidences the intrinsic structural complexity of this type of bimetallic systems, in which a fraction of monometallic Au, monometallic Pd and bimetallic nanoparticles of varying compositions coexist. This picture, which clearly contrasts with other much more homogeneous situations described in previous literature on bimetallic catalysts, also indicates the requirement of combining both atomic scale and macroscopic techniques to understand the structure of these catalysts. Concerning catalytic performance, a synergistic effect between Au and Pd has been observed in the selective oxidation of benzyl alcohol on ceria-zirconia. Moreover, the catalytic activity of these bimetallic Au-Pd catalysts is higher than that on other commonly used supports, such as activated carbon or carbon nanotubes. The treatments in oxidative and inert atmospheres at 250\ua0\ub0C improve the catalytic activity with respect to the fresh, un-pretreated, catalyst. Subsequent reduction of the oxidized bimetallic catalyst leads to an activity similar to that of the fresh catalyst, which is reduced at room temperature with H2 bubbles

Predation on Alouatta guariba clamitans Cabrera (Primates, Atelidae) by Leopardus pardalis (Linnaeus) (Carnivora, Felidae)

There are a few studies about predation on primates. Howler monkeys, being relatively large animals, were believed to be preyed on successfully only by medium to large-sized carnivores and large birds of prey. Our study took place at Chácara Payquerê, which is situated in the municipality of Balsa Nova, State of Paraná, Southern Brazil. Fingers and nails from Alouatta guariba clamitans Cabrera, 1940 were founded in two faecal samples from Leopardus pardalis (Linnaeus, 1758). With our documentation large howler monkey remains in faeces, the possibility of ocelot being a potential predator of all Neotropical primates should be taken into consideration.<br>São poucos os estudos sobre a predação de primatas. Sendo os bugios animais relativamente grandes, acredita-se que somente médios e grandes carnívoros e grandes rapineiros possam lograr sucesso em sua predação. O estudo foi realizado na Chácara Payquerê, situada no município de Balsa Nova, Estado do Paraná, sul do Brasil. Dedos e unhas de Alouatta guariba clamitans Cabrera, 1940 foram encontradas em duas amostras fecais de Leopardus pardalis (Linnaeus, 1758) que foram coletadas. Com este registro de grande primata em fezes, a possibilidade de a jaguatirica ser um potencial predador de todos os primatas neotropicais pode ser levada em consideração

Structure, chirality, and field testing of a male-produced aggregation pheromone of Asian palm weevilRhynchophorus bilineatus (Montr.) (Coleoptera: Curculionidae)

4-Methyl-5-nonanol is a male-produced aggregation pheromone of the Asian palm weevil,Rhynchophorus bilineatus (Montr.). The pheromone was identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometric (MS) analyses of male-and female-produced volatiles. Analyses by GC-EAD and GC-MS of weevil-produced and stereoselectively synthesized isomers of 4-methyl-5-nonanol on a Cyclodex B column, which separated isomers with baseline resolution, revealed that only (4S,5S)-4-methyl-5-nonanol is EAD active and produced by the males. In field experiments in Papua New Guinea, (4S,5S)-4-methyl-5-nonanol and a racemic mixture of disatereoisomers of it enhanced attraction of male and female weevils to sugarcane-baited traps. (4S,5S)-4-Methyl-5-nonanol is also an aggregation pheromone of two other Asian palm weevils.R. ferrugineus (Oliv.) andR. vulneratus (Panz.). The stereoisomeric mixture of 4-methyl-5-nonanol is currently used to manage populations ofR. bilineatus in Papua New GuineaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA