Kyungpook National University

About: Kyungpook National University is a education organization based out in Daegu, South Korea. It is known for research contribution in the topics: Population & Catalysis. The organization has 20497 authors who have published 42107 publications receiving 834608 citations.

Cobalt-phosphate complexes catalyze the photoelectrochemical water oxidation of BiVO4 electrodes.

Abstract: BiVO4 semiconductor electrodes were coupled with cobalt–phosphate complexes (CoPi) to enhance the photoelectrochemical (PEC) performance for water oxidation reaction. CoPi was deposited on a 550 nm-thick BiVO4 film viaelectrodeposition (ED) and photodeposition (PD) methods for comparison of their effects. The CoPi on BiVO4 exhibited Co : P atomic ratios of approximately 1 : 7 for the electrodeposited sample and approximately 1 : 18 for the photodeposited sample, and Co2+ and Co3+ co-existed in both samples. Optimized CoPi ED resulted in a CoPi overlayer of approximately 850 nm thick, which showed an electrochromic-like behavior that was likely due to limited access of phosphate into BiVO4 across the CoPi layer. Optimized CoPi PD, however, had very thin and rather uniform CoPi dispersion and did not show electrochromic-like behavior. Despite the lesser amount of CoPi, the PEC performance of BiVO4/CoPi (PD) was comparable to that of BiVO4/CoPi (ED). Real-time measurements of the headspace molecular oxygen that evolved from water oxidation indicated that CoPi enhances O2 production and photocurrent generation at BiVO4 by a factor of around 15 and a maximum of 20, respectively, at 0.576 VSCE (equivalent to 1.23 VRHE) under air mass 1.5 irradiation (400 mW cm−2). Prolonged irradiation of BiVO4/CoPi (ED) resulted in a reduced Co : P ratio to 1 : 1.77 without changing the mixed valency of Co(II/III). This finding indicates that incorporation of phosphate into the CoPi was kinetically slower than water oxidation. The primary role of CoPi has been suggested as a hole-conducting electrocatalyst making the photogenerated electrons more mobile and, consequently, increasing conductivity and boosting the PEC water oxidation performance of BiVO4.

Performance of τ-lepton reconstruction and identification in CMS

Abstract: The performance of tau-lepton reconstruction and identification algorithms is studied using a data sample of proton-proton collisions at sqrt(s)=7 TeV, corresponding to an integrated luminosity of 36 inverse picobarns collected with the CMS detector at the LHC. The tau leptons that decay into one or three charged hadrons, zero or more short-lived neutral hadrons, and a neutrino are identified using final-state particles reconstructed in the CMS tracker and electromagnetic calorimeter. The reconstruction efficiency of the algorithms is measured using tau leptons produced in Z-boson decays. The tau-lepton misidentification rates for jets and electrons are determined.

Secreted protein lipocalin-2 promotes microglial M1 polarization

Abstract: Activated macrophages are classified into two different forms: classically activated (M1) or alternatively activated (M2) macrophages. The presence of M1/M2 phenotypic polarization has also been suggested for microglia. Here, we report that the secreted protein lipocalin 2 (LCN2) amplifies M1 polarization of activated microglia. LCN2 protein (EC 1 μg/ml), but not glutathione S-transferase used as a control, increased the M1-related gene expression in cultured mouse microglial cells after 8-24 h. LCN2 was secreted from M1-polarized, but not M2-polarized, microglia. LCN2 inhibited phosphorylation of STAT6 in IL-4-stimulated microglia, suggesting LCN2 suppression of the canonical M2 signaling. In the lipopolysaccharide (LPS)-induced mouse neuroinflammation model, the expression of LCN2 was notably increased in microglia. Primary microglial cultures derived from LCN2-deficient mice showed a suppressed M1 response and enhanced M2 response. Mice lacking LCN2 showed a markedly reduced M1-related gene expression in microglia after LPS injection, which was consistent with the results of histological analysis. Neuroinflammation-associated impairment in motor behavior and cognitive function was also attenuated in the LCN2-deficient mice, as determined by the rotarod performance test, fatigue test, open-field test, and object recognition task. These findings suggest that LCN2 is an M1-amplifier in brain microglial cells.

Novel electrically conductive and ferromagnetic composites of poly(aniline‐co‐aminonaphthalenesulfonic acid) with iron oxide nanoparticles: Synthesis and characterization

Abstract: Nanocomposites of iron oxide (Fe3O4) with a sulfonated polyaniline, poly(aniline-co-aminonaphthalenesulfonic acid) [SPAN(ANSA)], were synthesized through chemical oxidative copolymerization of aniline and 5-amino-2-naphthalenesulfonic acid/1-amino-5-naphthalenesulfonic acid in the presence of Fe3O4 nanoparticles. The nanocomposites [Fe3O4/SPAN(ANSA)-NCs] were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, elemental analysis, UV–visible spectroscopy, thermogravimetric analysis (TGA), superconductor quantum interference device (SQUID), and electrical conductivity measurements. The TEM images reveal that nanocrystalline Fe3O4 particles were homogeneously incorporated within the polymer matrix with the sizes in the range of 10–15 nm. XRD pattern reveals that pure Fe3O4 particles are having spinel structure, and nanocomposites are more crystalline in comparison to pristine polymers. Differential thermogravimetric (DTG) curves obtained through TGA informs that polymer chains in the composites have better thermal stability than that of the pristine copolymers. FTIR spectra provide information on the structure of the composites. The conductivity of the nanocomposites (∼ 0.5 S cm−1) is higher than that of pristine PANI (∼ 10−3 S cm−1). The charge transport behavior of the composites is explained through temperature difference of conductivity. The temperature dependence of conductivity fits with the quasi-1D variable range hopping (quasi-1D VRH) model. SQUID analysis reveals that the composites show ferromagnetic behavior at room temperature. The maximum saturation magnetization of the composite is 9.7 emu g−1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007