Search

The solid oxide membrane (SOM) process is an environmentally friendly and innovative technology that can produce valuable metals directly from their oxides. In the SOM process, a yttria-stabilized zirconia (YSZ) tube is normally immersed the molten salt containing dissolved metal oxides and oxygen anions that move to the SOM tube where they are reduced without any emission. However, the YSZ phase transition and yttrium dissolution by the reaction with the flux reduce the SOM stability and lifetime. Here, we investigated the effect of powder characteristics on YSZ stability in the SOM electrolysis environment. Thus, powder with good formability such as high flowability and tap/untap density showed a 2% decrease in electrical conductivity, but a 17% decrease in low formability powders. The cause of the degradation is the penetration of salt ions into the lattice and the elution of yttrium ions, which results in a phase transition.

In this work, a facile synthetic method for site-selectively Pt-decorated PdPt bimetallic nanosheets (S-Pt-PdPtBN) has been described. The size, structure, and composition distribution of the synthesized S-Pt-PdPtBN were determined by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The electrocatalytic activity of these bimetallic nanosheets was examined for the oxidation of methanol in an acidic solution. The electrochemically active surface area (ECSA) of S-Pt-PdPtBN was 0.842 cm2. This value is slightly lower than the ECSA (1.012 cm2) of the commercial Pt/C (Alpha, Pt 10%) electrode. Interestingly, even though the ECSA of the S-Pt-PdPtBN/C was smaller than that of the commercial Pt/C, the forward peak current density of the former (2.95 mA cm−2) was ca. 1.5 times higher than that of the latter (2.05 mA cm−2). Moreover, the current density of the S-Pt-PdPtBN/C catalysts was high even after 800 s of continuous electrocatalysis at 0.5 V. This current density is six times that of commercial Pt/C catalysts. Thus, the synthesized S-Pt-PdPtBN exhibited significantly enhanced electrocatalytic activity and better stability than the commercial Pt/C catalyst for methanol oxidation.

Electric vehicles (EVs) require high operating voltages as well as high-capacity batteries. One candidate material that has received a great deal of attention is the nickel-substituted “high-voltage” spinel LiMn1.5Ni0.5O4, which offers the advantages of both higher capacity and higher operating voltage than spinel LiMn2O4. These features, along with the relatively benign constituent elements, have made this material a top choice for the next generation of high-power batteries. In this study, LiMn1.5Ni0.5O4−δ materials were synthesized by a microwave-assisted hydrothermal method. Analyses show that microwave irradiation enables the tuning of the Mn3+ concentration, which is related to the degree of disorder and enhances the electrochemical performance. However, with increasing synthesis time, the material limit of the elastic strain was exceeded, and the structure became morphologically unstable, which deteriorated the electrochemical performance. Thus, further efforts are necessary to improve its intrinsic stability. The LiMn1.5Ni0.5O4−δ cathode active material may be suitable for the rapid charging of electric vehicle batteries.

The beech mushrooms have customarily been revered by oriental societies for their nutritional and health benefits. We explored the mass spectrometry (MS) based spatial metabolomic variations between parts (cap and stipe) of two beech mushroom strains (brown and white). The principal component analysis (PCA) revealed their distinct primary (cap and stipe: PC1, 25.5%; strains: PC2, 12.5%) and secondary (cap and stipe: PC1, 10.3%; strains: PC2, 7.6%) metabolite patterns. The caps were rich in amino acids, fatty acids, and N-acetylglucosamine with higher protein and nitrogen contents. The stipes had abundant β-glucans, malic acid, and fructose. The discriminant secondary metabolites, especially, hypsiziprenols were higher in caps from brown strains. A fatty acid derivative, azelaic acid, was abundant in white strains (cap>stipe). We established a positive correlation for the cytotoxic activities of hypsiziprenols against ACHN cells. These spatial inter-strain metabolomic distinctions are potentially helpful for mushroom selection and improvement.

Summary Noble metal nanocrystals (NCs) with controlled morphologies and compositions have shown great applicable potentials as electrocatalytic materials. Recently, the incorporation of plasmonic function into NC-based electrocatalysts has been considered as a highly promising approach to promote the electrocatalytic activity and stability due to the synergism between plasmonic and catalytic functions. This review highlights the latest advancements in plasmon-enhanced electrocatalysis with multi-metallic heteronanostructures with integrated plasmonic and catalytic functions. We also provide a perspective for designing new types of heteronanostructures for plasmon-enhanced electrocatalysis, which can be useful to the development of a new class of energy conversion systems.

The size control of Pd dendritic nanoparticles (Pd-DNPs) is achieved with ascorbic acid as a reducing agent and cetyltrimethylammonium chloride (CTAC) as a surfactant by concentration. The size of Pd-DNPs can be controlled within the range of 38–88 nm by varying the amount of CTAC. Palladium nanoparticles are shown to have significantly increased in size due to the effect of dendritic pods and size with formic acid oxidation in the room temperature. The enhanced electrocatalytic properties of the Pd-DNPs are attributed to the presence of high surface. Moreover, the size controlled Pd-DNPs show enhanced intensity under surface-enhanced Raman spectroscopy via hot-spot or surface plasmon resonance (SPR) effects.

When concrete is exposed to temperature changes, its durability is reduced because of the decomposition of cement metrics generation of cracks within its structure as its component materials undergo different volumetric changes. Coarse aggregates play an important role in such behavior of concrete. We thus evaluated the influence of coarse aggregates on the fire resistance performance of a concrete structure by conducting a fire experiment under loading on two types of concrete, one with a granite-based coarse aggregate (NWC: normal weight concrete) and the other consisting of a clay-ash lightweight aggregate (LWC: lightweight concrete). LWC displayed a higher residual compressive strength than NWC under thermal load condition. NWC suffered from a large number of cracks at its interior at high temperatures, while the interior of the LWC demonstrated fewer cracks because of the voids in its interior to the mitigation of thermal expansion stress. When a load equivalent to 20% of its room temperature compressive strength was applied, both NWC and LWC demonstrated quasi-equilibrium between the thermal expansion strain and the loading-induced shrinkage strain. Whereas the 40% loading condition, the specimen exhibited shrinkage strain and its compressive strength was observed to undergo a sharp decrease from 500 °C.

A facile method to synthesize Bi-containing sea urchin-like Pt nanoparticles is demonstrated. The morphology and chemical composition of the prepared Bi-containing sea urchin-like Pt nanoparticles were characterized using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Electrochemical studies of the oxidation of methanol in an acidic medium using the Bi-containing sea urchin-like Pt nanoparticles were performed. The prepared nanoparticles exhibited enhanced electrocatalytic activity for methanol oxidation with a seven-fold higher oxidation current density and a more negative onset potential than commercial Pt/C (Pt 20%). Moreover, the current density of the Bi-containing sea urchin-like Pt nanoparticle/C catalysts was high even after 900 s of continuous electrocatalysis at 0.56 V. The synthesized Bi-containing sea urchin-like Pt nanoparticles should find attractive applications in various fields, such as fuel cells, sensors, and eletro- or organic catalysis.

Experiments with a Langmuir probe and optical emission spectroscopy (OES) combined with actinometry were performed in inductively coupled rf 13.56 MHz N 2 –Ar and O 2 –Ar discharges under the pressure range of 1–30 mTorr and the power range of 400–600 W. The Ar contents in the gas mixture were varied from 5% to 80%. The effect of the Ar content on the variation of the emission line intensities from various species was investigated. The dissociation fraction of nitrogen and oxygen molecules was obtained from the measured intensity peaks of light emission by using the OES actinometry. The dissociation fraction of N 2 molecules has a peak value at a specific pressure (11 mTorr). The electron density and the electron temperature were obtained by using a Langmuir probe to investigate the effects of the plasma parameters on the dissociation fraction. The electron density was observed to increase with the power while the electron temperature to decrease with the pressure and power.

The surface coating-dependent catalytic activity of icosahedral Au nanoparticles (IAuNPs) for the reduction of 4-nitrophenol by NaBH 4 in aqueous solution was investigated. Cetyltrimethylammonium bromide (CTAB)-stabilized IAuNPs with average size of 50 nm were prepared by three-step seeding protocol. The CTAB was then exchanged with several amine derivatives such as pyrrole, pyridine, 2,2′-bipyridine, and 4,4′-bipyridine. The catalytic reaction rates of nanoparticles are in the order of IAuNPs@4,4′-bpy > IAuNPs@2,2′-bpy > IAuNPs@pyridine > IAuNPs@pyrrole > IAuNPs@CTAB, revealing that the catalytic activity of the nanoparticles highly depends on the type and structure of the ligand molecules.

Helicobacter pylori (H. pylori) infection causes chronic gastritis and gastric cancer. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is a key enzyme that catalyzes the oxidation of prostaglandin E2 (PGE2) to 15-keto-PGE2. 15-PGDH is speculated as a tumor suppressor as its expression has been frequently down-regulated in diverse human malignancies including gastric cancer. However, the molecular mechanisms underlying 15-PGDH down-regulation in tumorigenesis remain largely unknown. In the present study, we found that the 15-PGDH expression was down-regulated in rat gastric mucosa (RGM)-1 cells infected with H. pylori. H. pylori induced hypermethylation of 15-PGDH promoter. The hypermethylation level of 15-PGDH was higher in the stomach biopsy from H. pylori-infected patients with gastritis than those without H. pylori infection. Notably, H. pylori induced the expression of DNA methyl transferase (DNMT) 1 through generation of reactive oxygen species (ROS). In H. pylori-infected C57BL/6 mice, 15-PGDH expression was reduced while DNMT1 expression was increased in the stomach tissues. In conclusion, H. pylori induces DNA methylation of CpG islands in the 15-PGDH promoter through up-regulation of DNMT1 expression, which is attributable to the generation of ROS.

Multi-branched gold nanoparticles were synthesized in high-yield through the reduction of HAuCl 4 by using hydrazine as a reducing agent. Practically 100% of the particles have numerous branches. The high reduction capability of hydrazine is found to be crucial for the formation of these branched gold nanoparticles. Their size can be controlled from 20 to 130 nm by varying the amounts of hydrazine. The prepared nanoparticles exhibit efficient surface-enhanced Raman scattering (SERS) properties and the SERS activity of the particles depends on the aspect ratio of their branches, which are most likely related to a great increase in the localized electromagnetic field enhancement from their unique sharp surface features arising from the branches.

Nanocrystalline gold octahedrons were synthesized in an aqueous environment via the reduction of HAuCl4 by ascorbic acid with the addition of NaOH. Highly monodisperse octahedral particles with controlled sizes ranging from 20 to 40 nm were prepared in high-yield by varying the reaction temperature. The structural and optical properties of the synthesized gold nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and UV–vis spectroscopy. The prepared nanoparticles exhibited efficient surface-enhanced Raman scattering (SERS) properties, and their SERS activities were highly size-dependent.

A fast and simple one-step method for the fabrication of stable gold nanoparticles-silica composites by using 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane(azacryptand) as a molecular anchor between nanoparticles and silica as well as reductant and stabilizer in the formation of the nanoparticles is reported. Gold nanoparticles-coated silica materials can be fabricated by mixing HAuCl 4 aqueous solution with the aqueous mixture of azacryptand and silica materials such as submicrometer silica particles and silica gel. The prepared nanoparticles-coated silica gel can effectively catalyze reduction of 4-nitrophenol by sodium borohydride in aqueous solution.

A new solution-phase method for synthesis of metal nanoparticles–carbon nanotubes (CNTs) assemblies is described. By injection of CNTs solution into the diethyl ether/aqueous solution of metal salt biphasic mixture, metal (Ag, Au, Pd, and Pt) nanoparticles–decorated CNTs composite materials can be prepared. Metal nanoparticles have spontaneously and selectively formed on the sidewalls of CNTs through redox reaction between CNTs and metal ions. This phenomenon has been probed by transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy.

The aqueous-phase synthesis of polyhedral gold nanoparticles with remarkably narrow size distribution is reported. By using a seeding growth approach, icosahedral gold particles with controllable size can be synthesized in high-yield. Citrate-capped 3.5 nm gold nanoparticles, prepared by the reduction of HAuCl 4 with sodium borohydride, are used as seeds. The synthesized gold nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The prepared gold nanoparticles show efficient surface-enhanced Raman scattering activities.

Amlodipine, a third-generation dihydropyridine calcium antagonist, is prescribed in the management of angina and hypertension. A newly developed amlodipine formulation (amlodipine camsylate) is associated with similar physical properties, melting point, and solubility-and improved stability against long-term stability test and accelerated temperature test-compared with the conventional formulation (amlodipine besylate).This study was performed to compare the pharmacokinetic (PK) and pharmacodynamic (PD) properties and safety profiles of a newly developed amlodipine formulation with a conventional formulation in healthy male subjects.This randomized, open-label, 2-period crossover comparative study was conducted at the Clinical Trial Center, Gil Medical Center, Gachon Medical School (Incheon, Korea). Eighteen healthy male Korean subjects aged 20 to 40 years were enrolled. All subjects received a single oral dose (5-mg tablet) of a conventional (reference) or newly developed (test) amlodipine formulation. Blood samples for PK analysis of amlodipine were obtained during the 144-hour period after dosing. Systolic and diastolic blood pressure (BP) (SBP and DBP, respectively) and pulse rate (PR) were measured just before each blood sampling. Assessment of safety profiles, including hematology and biochemistry, electrocardiography, urinalysis, and monitoring of adverse events (AEs), was performed.All participants completed both treatment periods. Their mean (SD) age was 22.3 (1.5) years (range, 20-25 years) and their mean (SD) body weight was 67.9 (5.6) kg (range, 57-77 kg). The plasma concentration-time profiles of amlodipine were similar after administration of the 2 formulations. The reference and test formulations were pharmacokinetically equivalent. The 90% CIs for the mean treatment ratios of the log-transformed peak plasma concentration and the area under the plasma concentration-time curve were within the predetermined equivalence range of 80% to 125%. Despite administration of a single dose, significant maximal changes in SBP, DBP, and PR were achieved after drug administration for both formulations compared with baseline values (all, P0.001). No significant differences in PD profiles were found between the 2 formulations. No clinically relevant changes were observed in physical, biochemical, hematologic, electrocardiographic, or urinalysis findings during the study. Neither formulation caused any AEs during the study.The 2 amlodipine formulations were pharmacokinetically equivalent and showed similar PD characteristics in these healthy male subjects.

Since ALWRs are anticipated to provide an enhanced margin of safety and newer nuclear power plants have a higher standard of severe accident safety performance than the existing plant designs, recent efforts aimed at simplifying the concept of EPZ for ALWR standard plant designs had been made by a group of utility companies through the EPRI in the U.S. In Korea, similar efforts have been made for the APR1400, which is a 1,400 MW-sized PWR of an advanced concept developed in Korea. This is possible due to a large enhancement in the performance of various accident mitigation features adopted in its design. The technical assessment shows that radius of the EPZ area of the APR1400 can be reduced to 700 in. However, even though the reduction in the EPZ area is well accepted through an extensive technical assessment process, it has been found that public acceptance appears to be a completely different matter. Therefore, this study performed a public poll to assess the degree of public acceptance to a reduction in the EPZ area and to identify the means of implementing the simplification of EPZ that would be most acceptable to the public.

S U N D A Y 339 Dust Mite Allergen In Bed Dust Predicts Rhinitis Symptom Persistence In Urban Pre-Adolescent Children With Higher Elemental Carbon Particulate Matter Exposure Dr. Young Yoo, MD, PhD, Dr. Luis M. Acosta, MD, Prof. Inge Goldstein, DrPH, Prof. Andrew Rundle, DrPH, Omar Olmedo, Adnan Divjan, Dr. Beihzhan Yan, Prof. Judith Jacobson, DrPH, Dr. Rachel L. Miller, MD, FAAAAI, Dr. Steven Chillrud, Prof. Matthew S. Perzanowski, PhD; Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, Department of Pediatrics, College of Medicine, Korea University, Seoul, South Korea, Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, Division of Pulmonary, Allergy and Critical Care Medicine, Columbia University, New York, NY. RATIONALE: Few studies have examined environmental risks for persistent rhinitis symptoms in urban populations during pre-adolescence. Combustion byproduct particulate matter has been shown to promote the Thelper cell-2 response to allergens. We hypothesized that preadolescents exposed to both combustion byproducts and domestic allergens would have more persistent rhinitis symptoms than those exposed to one or neither. METHODS: The New York City (NYC) Neighborhood Asthma and Allergy Study recruited 7-8 year-old children with (cases) and without (controls) asthma through a health insurance plan. Bed dust was collected for measurement of indoor allergens. Neighborhood-level annual outdoor elemental carbon (EC) was estimated for each child at baseline based on NYC Community Air Survey data. Questionnaires were administered at age 7-8 and age 9-10. Children reported to have had rhinitis symptoms in the past 12 months were categorized as having ‘‘current rhinitis.’’ RESULTS: Of 102 children who had current rhinitis at age 7-8 and were followed for 2 years, 54 (53%) had current rhinitis symptoms at age 9-10. In multivariable regression analyses, neither dust-borne allergen concentrations nor EC concentration were associated with persistence of rhinitis. However, Der f 1 concentration was associated with rhinitis persistence (relative risk (RR)51.33, P50.03) among the children with higher EC (greater than median)[Pinteraction50.096]. CONCLUSIONS: Children with rhinitis may be more likely to have persistent symptoms if they are also exposed to combustion byproduct particulate matter than if they are not. Exposure to EC may thus contribute to the persistence of rhinitis symptoms in urban communities.