Use of A-Site Metal Exsolution from a Hydrated Perovskite Titanate for Combined Steam and CO2 Reforming of Methane.

Metal segregation from a perovskite oxide (ABO3) usually referring to "redox metal exsolution" has recently been used for in situ preparation of a well-designed catalyst where metal nanoparticles are homogeneously and strongly embedded on perovskite scaffolds upon reduction. The exsolution concept of B-site transition metal ions has grown, but several issues such as segregation of A-site alkaline-earth metal ions (altering electronic structures of the perovskite surface, causing deformation of perovskite structures, or creating undesirable products via side reactions) and carbon formations on metal nanoparticles should be addressed for stable catalysts in greenhouse gas (CO2 or CH4) conversion. Here, we suggest a new approach to designing metal-perovskite composite catalysts via A-site metal segregation from a hydrated perovskite titanate. In situ formation of A-site-deficient hydrated CaTiO3 accompanied with Ni exsolution solids leads to ∼78 and 65% of CH4 and CO2 conversion, respectively, suppressing carbon formations and alkaline-earth metal segregations in combined steam and carbon dioxide reforming of methane at 700 °C. It would help to design active and stable metal-perovskite catalysts for energy and environmental applications.

Harnessing Strong Metal-Support Interaction to Proliferate the Dry Reforming of Methane Performance by In Situ Reduction.

The strong bonding at the interface between the metal and the support, which can inhibit the undesirable aggregation of metal nanoparticles and carbon deposition from reforming of hydrocarbon, is well known as the classical strong metal-support interaction (SMSI). SMSI of nanocatalysts was significantly affected by heat treatment and reducing conditions during catalyst preparation.the heat treatment and reduction conditions during catalyst preparation. SMSI can be weakened by the decrement of metal-doped sites in the supporting oxide and can often deactivate catalysts by the encapsulation of active sites through these processes. To retain SMSI near the active sites and to enhance the catalytic activity of the nanocatalyst, it is essential to increase the number of surficial metal-doped sites between nanometal and the support. Herein, we propose a mild reduction process using dry methane (CH4/CO2) gas that suppresses the aggregation of nanoparticles and increases the exposed interface between the metal and support, Ni and cerium oxide. The effects of mild reduction on the chemical state of Ni-cerium oxide nanocatalysts were specifically investigated in this study. As a result, mild reduction led to form large amounts of the Ni3+ phase at the catalyst surface of which SMSI was significantly enhanced. It can be easily fabricated while the dry reforming of methane (DRM) reaction is on stream. The superior performance of the catalyst achieved a considerably high CH4 conversion rate of approximately 60% and stable operation up to 550 h at a low temperature, 600 °C.

Effects of dispersed copper nanoparticles on Ni-ceria based dry methanol fuelled low temperature solid oxide fuel cells.

Methanol is an attractive energy source due to its portability and thermodynamic coke resistance by its oxygen content. In order to operate dry methanol fuel low temperature solid oxide fuel cells (LT-SOFCs), it is important to solve the problems of carbon formation and its low performance. In this study, copper impregnation was selected to decrease the carbon deposition and enhance the performance at low temperature. The interaction of copper, ceria and nickel improves CO oxidation capacity which improves coke tolerance and nano-sized nickel copper alloys improved durability and catalytic performance under methanol feed. It markedly amplified the performance about 0.4 W cm-2 at 550 °C with the durable operation at 1.4 A cm-2 over 50 h. Loading copper nanoparticles is promising method for Ni-ceria based LT-SOFC using methanol fuel with high performance and stable operation.

Selective Ion Transporting Polymerized Ionic Liquid Membrane Separator for Enhancing Cycle Stability and Durability in Secondary Zinc-Air Battery Systems.

Rechargeable secondary zinc-air batteries with superior cyclic stability were developed using commercial polypropylene (PP) membrane coated with polymerized ionic liquid as separators. The anionic exchange polymer was synthesized copolymerizing 1-[(4-ethenylphenyl)methyl]-3-butylimidazolium hydroxide (EBIH) and butyl methacrylate (BMA) monomers by free radical polymerization for both functionality and structural integrity. The ionic liquid induced copolymer was coated on a commercially available PP membrane (Celguard 5550). The coat allows anionic transfer through the separator and minimizes the migration of zincate ions to the cathode compartment, which reduces electrolyte conductivity and may deteriorate catalytic activity by the formation of zinc oxide on the surface of the catalyst layer. Energy dispersive X-ray spectroscopy (EDS) data revealed the copolymer-coated separator showed less zinc element in the cathode, indicating lower zinc crossover through the membrane. Ion coupled plasma optical emission spectroscopy (ICP-OES) analysis confirmed over 96% of zincate ion crossover was reduced. In our charge/discharge setup, the constructed cell with the ionic liquid induced copolymer casted separator exhibited drastically improved durability as the battery life increased more than 281% compared to the pure commercial PP membrane. Electrochemical impedance spectroscopy (EIS) during the cycle process elucidated the premature failure of cells due to the zinc crossover for the untreated cell and revealed a substantial importance must be placed in zincate control.

Synthesis and application of hexagonal perovskite BaNiO3 with quadrivalent nickel under atmospheric and low-temperature conditions.

A hexagonal perovskite BaNiO3 with unusually high-valence nickel(iv) was synthesized under atmospheric and low-temperature conditions by an ethylenediamine-derived wet-chemical route. Secondary phases disappeared with increase in the pH value, and the single-phase BaNiO3 was successfully synthesized at pH 10. The specific surface area was ∼32 m(2) g(-1), which is significantly enhanced compared to the BaNiO3 (0.3 m(2) g(-1)) synthesized by flux-mediated crystal growth. The BaNiO3 was used as an oxygen-evolution reaction (OER) catalyst, and the specific mass activity was ∼5 times higher than that of the BaNiO3 synthesized by flux-mediated crystal growth. As a result, the ethylenediamine-derived sol-gel synthesis could be a simple technique to prepare crystalline compounds such as perovskites and spinels, with unusually high-valence transition metals.

A New Family of Perovskite Catalysts for Oxygen-Evolution Reaction in Alkaline Media: BaNiO3 and BaNi(0.83)O(2.5).

Establishment of a sustainable energy society has been strong driving force to develop cost-effective and highly active catalysts for energy conversion and storage devices such as metal-air batteries and electrochemical water splitting systems. This is because the oxygen evolution reaction (OER), a vital reaction for the operation, is substantially sluggish even with precious metals-based catalysts. Here, we show for the first time that a hexagonal perovskite, BaNiO3, can be a highly functional catalyst for OER in alkaline media. We demonstrate that the BaNiO3 performs OER activity at least an order of magnitude higher than an IrO2 catalyst. Using integrated density functional theory calculations and experimental validations, we unveil that the underlying mechanism originates from structural transformation from BaNiO3 to BaNi(0.83)O(2.5) (Ba6Ni5O15) over the OER cycling process.

Tailoring gadolinium-doped ceria-based solid oxide fuel cells to achieve 2 W cm(-2) at 550 °C.

Low-temperature operation is necessary for next-generation solid oxide fuel cells due to the wide variety of their applications. However, significant increases in the fuel cell losses appear in the low-temperature solid oxide fuel cells, which reduce the cell performance. To overcome this problem, here we report Gd0.1Ce0.9O1.95-based low-temperature solid oxide fuel cells with nanocomposite anode functional layers, thin electrolytes and core/shell fibre-structured Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Gd0.1Ce0.9O1.95 cathodes. In particular, the report describes the use of the advanced electrospinning and Pechini process in the preparation of the core/shell-fibre-structured cathodes. The fuel cells show a very high performance of 2 W cm(-2) at 550 °C in hydrogen, and are stable for 300 h even under the high current density of 1 A cm(-2). Hence, the results suggest that stable and high-performance solid oxide fuel cells at low temperatures can be achieved by modifying the microstructures of solid oxide fuel cell components.

Muju virus, harbored by Myodes regulus in Korea, might represent a genetic variant of Puumala virus, the prototype arvicolid rodent-borne hantavirus.

The genome of Muju virus (MUJV), identified originally in the royal vole (Myodes regulus) in Korea, was fully sequenced to ascertain its genetic and phylogenetic relationship with Puumala virus (PUUV), harbored by the bank vole (My. glareolus), and a PUUV-like virus, named Hokkaido virus (HOKV), in the grey red-backed vole (My. rufocanus) in Japan. Whole genome sequence analysis of the 6544-nucleotide large (L), 3652-nucleotide medium (M) and 1831-nucleotide small (S) segments of MUJV, as well as the amino acid sequences of their gene products, indicated that MUJV strains from different capture sites might represent genetic variants of PUUV, the prototype arvicolid rodent-borne hantavirus in Europe. Distinct geographic-specific clustering of MUJV was found in different provinces in Korea, and phylogenetic analyses revealed that MUJV and HOKV share a common ancestry with PUUV. A better understanding of the taxonomic classification and pathogenic potential of MUJV must await its isolation in cell culture.

Whole-genome sequence of muju virus, an arvicolid rodent-borne hantavirus.

The complete genome sequence of Muju virus was determined from lung tissue samples of three royal voles (Myodes regulus) captured in Gangwon province in the Republic of Korea. Since few whole genome sequences of hantaviruses are available, this sequence may help to clarify the molecular phylogeny of arvicolid rodent-borne hantaviruses.

Hypoglossal canal dural arteriovenous fistula: incidence and the relationship between symptoms and drainage pattern.

OBJECT: The purpose of this study was to evaluate the incidence, radiographic findings, relationship between presenting symptoms for treatment and drainage pattern, and treatment outcomes of hypoglossal canal dural arteriovenous fistula (HC-dAVF). METHODS: During a 16-year period, 238 patients underwent endovascular treatment for cranial dAVF at a single center. The incidence, radiographic findings, relationship between presenting symptoms for treatment and drainage pattern, and treatment outcomes of HC-dAVF were retrospectively evaluated. RESULTS: The incidence of HC-dAVF was 4.2% (n = 10). Initial symptoms were tinnitus with headache (n = 6), tinnitus only (n = 1), ocular symptoms (n = 1), otalgia (n = 1), and congestive myelopathy (n = 1). Presenting symptoms requiring treatment included ocular symptoms (n = 4), hypoglossal nerve palsy (n = 4), aggravation of myelopathy (n = 1), and aggravation of tinnitus with headache (n = 1). While the affected HC was widened in 4 of 10 patients, hypersignal intensity on source images was conspicuous in all 7 patients who underwent MR angiography (MRA). All ocular symptoms and congestive myelopathy were associated with predominant drainage to superior ophthalmic or perimedullary veins due to antegrade drainage restriction. All patients who underwent transvenous coil embolization (n = 8) or transarterial N-butyl cyanoacrylate (NBCA) embolization (n = 1) improved without recurrence. One patient who underwent transarterial particle embolization had a recurrence 12 months posttreatment and was retreated with transvenous embolization. CONCLUSIONS: The incidence of HC-dAVF was 4.2% of all cranial dAVF patients who underwent endovascular treatment. Source images of MRA helped to accurately diagnose HC-dAVF. More aggressive symptoms may develop as a result of a change in the predominant drainage route due to the development of venous stenosis or obstruction over time. Transvenous coil embolization appears to be the first treatment of choice.

Coprecipitation synthesis and characterization of La0.8Sr0.2Ga(0.8-x)Mg0.2Co(x)O2.8 for intermediate temperature solid oxide fuel cell electrolytes.

La0.8Sr0.2Ga(0.8-x)Mg0.2CO(x)O2.8 (LSGMC) electrolyte powders containing different amount of Co (0 < or = x < or = 0.15) were prepared by ammonium carbonate coprecipitation method. The precursors, the calcined powders, and the sintered pellets were characterized by thermogravimetry/differential thermal analysis, X-ray diffractometry, scanning electron microscopy, and an impedance analyzer. The thermal decomposition of the LSGMC precursors was completed at around 900 degrees C with the total weight loss of approximately 35%. The LSGMC samples sintered at 1350 degrees C consisted of the pure perovskite structure. The ionic conductivity was significantly improved by Co doping for the Ga-site of the La0.8Sr0.2Ga0.8Mg0.2O2.8 (LSGM) electrolytes. The ionic conductivity of LSGMC (x = 0.1) exhibited the highest values of 1.6 x 10(-1) S cm(-1) at 700 degrees C with an activation energy for the oxide-ion conduction of 0.29 eV. The results of this study indicated that the Co-doped LSGM electrolytes had excellent properties for use as an electrolyte in an IT-SOFC and the ammonium carbonate coprecipitation process could be employed as the efficient method for the preparation of the Co-doped LSGM electrolytes.

Oculogyric crisis associated with disulfiram-induced pallidonigral lesion.

We report a man who developed oculogyric crisis one month after disulfiram intoxication. Brain MRI showed lesions involving bilateral globus pallidus and left substantia nigra. In our patient, neuronal discharges from pathologically reorganized basal ganglia circuit to the mid-brain ocular motor center might lead to tonic deviation of the eyes.

Clinical and pathological characteristics of four Korean patients with limb-girdle muscular dystrophy type 2B.

Limb-girdle muscular dystrophy type 2B (LGMD2B), a subtype of autosomal recessive limb-girdle muscular dystrophy (ARLGMD), is characterized by a relatively late onset and slow progressive course. LGMD2B is known to be caused by the loss of the dysferlin protein at sarcolemma in muscle fibers. In this study, the clinical and pathological characteristics of Korean LGMD2B patients were investigated. Seventeen patients with ARLGMD underwent muscle biopsy and the histochemical examination was performed. For the immunocytochemistry, a set of antibodies against dystrophin, alpha, beta, gamma, delta-sarcoglycans, dysferlin, caveolin-3, and beta-dystroglycan was used. Four patients (24%) showed selective loss of immunoreactivity against dysferlin at the sarcolemma on the muscle specimens. Therefore, they were classified into the LGMD2B category. The age at the onset of disease ranged from 9 yr to 33 yr, and none of the patients was wheelchair bound at the neurological examination. The serum creatine kinase (CK) was high in all the patients (4010-5310 IU/L). The pathologic examination showed mild to moderate dystrophic features. These are the first Korean LGMD2B cases with a dysferlin deficiency confirmed by immunocytochemistry. The clinical, pathological, and immunocytochemical findings of the patients with LGMD2B in this study were in accordance with those of other previous reports.

Prediction of early clinical severity and extent of neuronal damage in anterior-circulation infarction using the initial serum neuron-specific enolase level.

CONTEXT: Prompt and precise measurement of neuronal damage in acute cerebral infarction is important to determine the prognosis of functional outcome. A feasible biochemical marker such as the neuron-specific enolase (NSE) level has been used to detect various diseases involving the central nervous system. OBJECTIVE: To determine whether the initial serum NSE level is a useful marker for predicting the severity of clinical neurological deficits and the extent of neuronal damage in acute anterior-circulation infarction. DESIGN: Case-control study with biochemical-clinicoradiological correlation. SETTING: Tertiary care center. PARTICIPANTS: Eighty-one patients and 77 age- and sex-matched control subjects. MAIN OUTCOME MEASURES: Patients with anterior-circulation infarction underwent intravenous serum NSE sampling within 24 hours after symptom onset. Recent infarction was confirmed by T2-weighted and diffusion-weighted magnetic resonance imaging of the brain about 1 week after the onset of stroke. Volumetric analysis of infarction was also performed. The National Institutes of Health Stroke Scale score was measured on admission to the hospital and 1 week after symptom onset. RESULTS: The patients' initial serum NSE levels were statistically significantly higher than the controls (P<.05). The initial serum NSE level highly correlated with the volume of infarction seen on T2-weighted magnetic resonance imaging of the brain (r = 0.62, P<.001) and with the National Institutes of Health Stroke Scale score obtained on hospital admission (r = 0.42, P =.002) and on the seventh day after the onset of stroke (r = 0.44, P<.001). CONCLUSION: The initial serum NSE level is a reliable predictor for the extent of neuronal damage and the severity of clinical neurological deficits in acute anterior-circulation infarction.

The effect of initial serum neuron-specific enolase level on clinical outcome in acute carotid artery territory infarction.

The prediction of functional outcome in patients with acute cerebral infarction depends on many factors. Various techniques have been applied to predict severity and outcome after cerebral infarction. Neuron-specific enolase (NSE) is a component of a specific brain enzyme and a useful marker of brain injury. We evaluated the relation between initial serum NSE level and short- and long-term clinical outcome in 59 patients with acute cerebral infarction and in 38 age-matched healthy controls. Serum NSE levels were determined in patients with carotid artery (CA) territory cerebral infarction within 24 hours of onset. Brain MRI was performed four to seven days after stroke. Patients were divided into two groups: large CA territory infarction with a lesion extending cortex (cortex group), and small subcortical CA territory infarction (subcortical group) with a lesion confined to the subcortical white matter. We compared the initial serum NSE levels of the two groups. National Institute of Health Stroke Scale (NIHSS) was determined at admission and seven days after onset and the modified Rankin's scale was used at the 3 months follow-up after onset. Serum NSE levels were significantly elevated in patients with acute cerebral infarction compared with the normal controls (13.88 +/- 5.47 ng/dl vs. 8.15 +/- 1.53 ng/dl, p < 0.05). The initial (< 24 h) serum NSE level was higher in the cortical group than in the subcortical group (16.68 +/- 5.70 ng/dl vs. 10.98 +/- 3.34 ng/dl, p < 0.05). NIHSS on admission and on the 7th day correlated with the initial serum NSE level (p < 0.05), as were more severe functional outcomes, as determined 3 months after onset (p < 0.05). This study shows that initial serum NSE level may be a useful marker for severity in acute ischemic stroke, and that it may be well correlated with short-term and long-term functional outcomes.