National Cheng Kung University

About: National Cheng Kung University is a education organization based out in Tainan City, Taiwan. It is known for research contribution in the topics: Population & Thin film. The organization has 49723 authors who have published 69799 publications receiving 1437420 citations. The organization is also known as: NCKU.

Graphite Oxide with Different Oxygenated Levels for Hydrogen and Oxygen Production from Water under Illumination: The Band Positions of Graphite Oxide

Abstract: Graphite oxide (GO) photocatalysts derived from graphite oxidation can have varied electronic properties by varying the oxidation level. Absorption spectroscopy shows the increasing band gap of GO with the oxygen content. Electrochemical analysis along with the Mott–Schottky equation show that the conduction and valence band edge levels of GO from appropriate oxidation are suitable for both the reduction and the oxidation of water. The conduction band edge shows little variation with the oxidation level, and the valence band edge governs the bandgap width of GO. The photocatalytic activity of GO specimens with various oxygenated levels was measured in methanol and AgNO3 solutions for evolution of H2 and O2, respectively. The H2 evolution was strong and stable over time, whereas the O2 evolution was negligibly small due to mutual photocatalytic reduction of the GO with upward shift of the valence band edge under illumination. The conduction band edge of GO showed a negligible change with the illumination. ...

Giant and anisotropic many-body spin–orbit tunability in a strongly correlated kagome magnet

Abstract: Owing to the unusual geometry of kagome lattices—lattices made of corner-sharing triangles—their electrons are useful for studying the physics of frustrated, correlated and topological quantum electronic states1–9. In the presence of strong spin–orbit coupling, the magnetic and electronic structures of kagome lattices are further entangled, which can lead to hitherto unknown spin–orbit phenomena. Here we use a combination of vector-magnetic-field capability and scanning tunnelling microscopy to elucidate the spin–orbit nature of the kagome ferromagnet Fe3Sn2 and explore the associated exotic correlated phenomena. We discover that a many-body electronic state from the kagome lattice couples strongly to the vector field with three-dimensional anisotropy, exhibiting a magnetization-driven giant nematic (two-fold-symmetric) energy shift. Probing the fermionic quasi-particle interference reveals consistent spontaneous nematicity—a clear indication of electron correlation—and vector magnetization is capable of altering this state, thus controlling the many-body electronic symmetry. These spin-driven giant electronic responses go well beyond Zeeman physics and point to the realization of an underlying correlated magnetic topological phase. The tunability of this kagome magnet reveals a strong interplay between an externally applied field, electronic excitations and nematicity, providing new ways of controlling spin–orbit properties and exploring emergent phenomena in topological or quantum materials10–12. The topological magnet Fe3Sn2 exhibits a giant nematic energy shift of a many-body electronic state, demonstrating anisotropic spin–orbit tunability.

Associations between urinary phthalate monoesters and thyroid hormones in pregnant women

Abstract: BACKGROUND: Maternal hypothyroidism during pregnancy can cause adverse effects in the fetus. Scientific evidence has shown that probable thyroid-like function of some phthalates in vitro and in vivo, and phthalates exposure, can begin in utero. This study investigated the association between phthalate exposure and thyroid hormones in pregnant women. METHODS: Serum and spot urine samples were collected from 76 Taiwanese pregnant women at second trimester. Thyroid hormones, including thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4) and free T4 (FT4) were analysed in serum samples, and five urinary phthalate monoesters, including mono butyl phthalate (MBP), monoethyl phthalate (MEP) and mono ethylhexyl phthalate (MEHP), were measured. RESULTS: Urinary MBP, MEP and MEHP, the median levels of which were 81.8, 27.7 and 20.6 ng/ml, respectively, were the predominant substances in the urinary phthalate monoesters. Significant mild negative correlations were found between T4 and urinary MBP (R 52 0.248, P< 0.05), and between FT4 and urinary MBP (R 52 0.368, P< 0.05). After adjusting for age, BMI and gestation, urinary MBP levels showed negative associations with FT4 and T4 (FT4: b 52 0.110, P< 0.001; T4: b520.112, P 5 0.003). CONCLUSIONS: Exposure to di-n-butyl phthalate (DBP) may affect thyroid activity in pregnant women, but how DBP affects thyroid function is unclear. Further studies are needed to elucidate the mechanism of action and to investigate whether any other factors related to DBP exposure alter the thyroid function.

Histone deacetylase inhibitors up-regulate astrocyte GDNF and BDNF gene transcription and protect dopaminergic neurons

Abstract: Parkinson's disease (PD) is characterized by the selective and progressive loss of dopaminergic (DA) neurons in the midbrain substantia nigra. Currently, available treatment is unable to alter PD progression. Previously, we demonstrated that valproic acid (VPA), a mood stabilizer, anticonvulsant and histone deacetylase (HDAC) inhibitor, increases the expression of glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) in astrocytes to protect DA neurons in midbrain neuron-glia cultures. The present study investigated whether these effects are due to HDAC inhibition and histone acetylation. Here, we show that two additional HDAC inhibitors, sodium butyrate (SB) and trichostatin A (TSA), mimic the survival-promoting and protective effects of VPA on DA neurons in neuron-glia cultures. Similar to VPA, both SB and TSA increased GDNF and BDNF transcripts in astrocytes in a time-dependent manner. Furthermore, marked increases in GDNF promoter activity and promoter-associated histone H3 acetylation were noted in astrocytes treated with all three compounds, where the time-course for acetylation was similar to that for gene transcription. Taken together, our results indicate that HDAC inhibitors up-regulate GDNF and BDNF expression in astrocytes and protect DA neurons, at least in part, through HDAC inhibition. This study indicates that astrocytes may be a critical neuroprotective mechanism of HDAC inhibitors, revealing a novel target for the treatment of psychiatric and neurodegenerative diseases.