An advanced and efficient Co3O4/C nanocomposite for the oxygen evolution reaction in alkaline media

The design of efficient nonprecious catalysts for the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) is a necessary, but very challenging task to uplift the water-based economy. In this study, we developed a facile approach to produce porous carbon from the dehydration of sucrose and use it for the preparation of nanocomposites with cobalt oxide (Co₃O₄). The nanocomposites were studied by the powder X-ray diffraction and scanning electron microscopy techniques, and they exhibited the cubic phase of cobalt oxide and porous structure of carbon. The nanocomposites showed significant OER activity in alkaline media, and the current densities of 10 and 20 mA cm⁻² could be obtained at 1.49 and 1.51 V versus reversible hydrogen electrode (RHE), respectively. The impedance study confirms favorable OER activity on the surface of the prepared nanocomposites. The nanocomposite is cost-effective and can be capitalized in various energy storage technologies.

The design of efficient nonprecious catalysts for the hydrogen evolution reaction (HER) or the oxygen evolution reaction (OER) is a necessary, but very challenging task to uplift the water-based economy.     

Investigating a crow die-off in January–February 2011 during the introduction of a new clade of highly pathogenic avian influenza virus H5N1 into Bangladesh

We investigated unusual crow mortality in Bangladesh during January-February 2011 at two sites. Crows of two species, Corvus splendens and C. macrorhynchos, were found sick and dead during the outbreaks. In selected crow roosts, morbidity was ~1 % and mortality was ~4 % during the investigation. Highly pathogenic avian influenza virus H5N1 clade 2.3.2.1 was isolated from dead crows. All isolates were closely related to A/duck/India/02CA10/2011 (H5N1) with 99.8 % and A/crow/Bangladesh/11rs1984-15/2011 (H5N1) virus with 99 % nucleotide sequence identity in their HA genes. The phylogenetic cluster of Bangladesh viruses suggested a common ancestor with viruses found in poultry from India, Myanmar and Nepal. Histopathological changes and immunohistochemistry staining in brain, pancreas, liver, heart, kidney, bursa of Fabricius, rectum, and cloaca were consistent with influenza virus infection. Through our limited investigation in domesticated birds near the crow roosts, we did not identify any samples that tested positive for influenza virus A/H5N1. However, environmental samples collected from live-bird markets near an outbreak site during the month of the outbreaks tested very weakly positive for influenza virus A/H5N1 in clade 2.3.2.1-specific rRT-PCR. Continuation of surveillance in wild and domestic birds may identify evolution of new avian influenza virus and associated public-health risks.     

Does Self-Selection Affect Samples’ Representativeness in Online Surveys? An Investigation in Online Video Game Research

Background

The number of medical studies performed through online surveys has increased dramatically in recent years. Despite their numerous advantages (eg, sample size, facilitated access to individuals presenting stigmatizing issues), selection bias may exist in online surveys. However, evidence on the representativeness of self-selected samples in online studies is patchy.

Objective

Our objective was to explore the representativeness of a self-selected sample of online gamers using online players’ virtual characters (avatars).

Methods

All avatars belonged to individuals playing World of Warcraft (WoW), currently the most widely used online game. Avatars’ characteristics were defined using various games’ scores, reported on the WoW’s official website, and two self-selected samples from previous studies were compared with a randomly selected sample of avatars.

Results

We used scores linked to 1240 avatars (762 from the self-selected samples and 478 from the random sample). The two self-selected samples of avatars had higher scores on most of the assessed variables (except for guild membership and exploration). Furthermore, some guilds were overrepresented in the self-selected samples.

Conclusions

Our results suggest that more proficient players or players more involved in the game may be more likely to participate in online surveys. Caution is needed in the interpretation of studies based on online surveys that used a self-selection recruitment procedure. Epidemiological evidence on the reduced representativeness of sample of online surveys is warranted.     

Polypyrrole nanoparticles-based soft actuator for artificial muscle applications

Currently, a straightforward fabrication technique for the development of soft actuators to explore their potential in robotic applications using environmentally compatible raw materials represents an important challenge. A conventional conducting polymer, such as polypyrrole (PPy), shows promising conductivity for such applications. This study presents the synthesis of PPy/polyvinyl alcohol (PPy/PVA)-based ion exchange polymer films containing PEDOT:PSS/SWNT/IL electrodes that undergo conformational changes in response to the applied voltage. Four types of ionic polymer actuator films with different sizes of PPy nanoparticles were fabricated to investigate the size-dependent electromechanical actuation performance. The aim of this study is to design and develop a stable, flexible, and reliable film actuator for robotic applications. Scanning electron microscopy and transmittance electron microscopy were performed to observe the surface morphology and detailed structure of the fabricated actuator films. The current density and ionic conductivity are demonstrated by the cyclic voltammogram and linear sweep voltammogram, respectively. The enhanced values of the water uptake, ion exchange capacity and ionic conductivity of the PPy/PVA polymer composite films enhanced the electrical properties and the tip deflection performance as compared to those of the other reported expensive perfluorinated polymer-based membrane actuators. A two finger-based micro gripping device was also developed, in which both the fingers were made up of the O-PPy/PVA/EL-based ion exchange polymer films. This mechanically stable and flexible film actuator fabricated via a synergistic combination of PPy/PVA composition containing PEDOT:PSS/SWNT/IL electrode surfaces possesses a substantial potential as an actuator material for micro robotic applications.

Currently, a straightforward fabrication technique for the development of soft actuators to explore their potential in robotic applications using environmentally compatible raw materials represents an important challenge.     

Anihypercholesterolemic effect of Semecarpus anacardium Linn nut milk extract in high-cholesterol-fed rats

The present study was carried to bring about the hypolipidemic effect of the drug Semecarpus anacardium Linn nut milk extract (SA) in hypercholesterolemia-induced rat model. Adult male Wistar rats were divided into four groups which included control rats, hypercholesterolemia-induced rats (high-cholesterol diet (4 %) for 30 days), hypercholesterolemic rats treated with the drug SA (200 mg/kg/b. wt oil), and the control rats treated with the drug SA (200 mg/kg/b. wt). Increased level of ROS and lipid peroxides were observed in hypercholesterolemic rats, whereas the levels of activities of antioxidant enzymes were found to be decreased in animals fed with a high-fat diet. Simultaneous administration of SA to these rats reverted back the changes to near-normal levels. Similarly, an increase in the expression of iNOS and LOX-1 were observed in high-fat-fed rats when compared to normal rats. Upon treatment with the drug SA, their expressions were brought back to near-normal levels. No adverse effects were observed in SA-alone treated group of rats, indicating its protective nature. The present study suggests that SA could play a protective role against hypercholesterolemia, thereby preventing coronary heart disease.     

A Rare Case of Hemolytic Anemia in a Pediatric Patient Due to Ring Dehiscence After Mitral Valve Repair: Utility of Real-Time Three-Dimensional Imaging and Management

A rare case of hemolytic anemia in a 3-year-old child due to mitral valve ring dehiscence is described. The dehiscence of mitral valve ring was diagnosed utilizing real-time three-dimensional echocardiography. The patient subsequently underwent reoperation with successful resolution of hemolysis after replacement of the ring.     

BMC Medicine: a decade of open access medical research

On 24 November 2003, BMC Medicine published its first article. Ten years and over 900 articles later we look back at some of the most notable milestones for the journal and discuss advances and innovations in medicine over the last decade. Our editorial board members, Leslie Biesecker, Thomas Powles, Chris Del Mar, Robert Snow and David Moher, also comment on the changes they expect to see in their fields over the coming years.