Tunable resistivity of correlated VO2(A) and VO2(B) via tungsten doping

Applications of correlated vanadium dioxides VO2(A) and VO2(B) in electrical devices are limited due to the lack of effective methods for tuning their fundamental properties. We find that the resistivity of VO2(A) and VO2(B) is widely tunable by doping them with tungsten ions. When x < 0.1 in V1−xWxO2(A), the resistivity decreases drastically by four orders of magnitude with increasing x, while that of V1−xWxO2(B) shows the opposite behaviour. Using spectroscopic ellipsometry and X-ray photoemission spectroscopy, we propose that correlation effects are modulated by either chemical-strain-induced redistribution of V−V distances or electron-doping-induced band filling in V1−xWxO2(A), while electron scattering induced by disorder plays a more dominant role in V1−xWxO2(B). The tunable resistivity makes correlated VO2(A) and VO2(B) appealing for next-generation electronic devices. © 2020, The Author(s).1

Enzymatic synthesis of chlorogenic acid glucoside using dextransucrase and its physical and functional properties

Chlorogenic acid, a major polyphenol in edible plants, possesses strong antioxidant activity, anti-lipid peroxidation and anticancer effects. It used for industrial applications; however, this is limited by its instability to heat or light. In this study, we, for the first time synthesized chlorogenic acid glucoside (CHG) via transglycosylation using dextransucrase from Leuconostoc mesenteroides and sucrose. CHG was purified and its structure determined by nuclear magnetic resonance and matrix-associated laser desorption ionization–time-of-flight mass spectroscopy. The production yield of CHG was 44.0% or 141 mM, as determined by response surface methodology. CHG possessed a 65% increase in water solubility and a 2-fold browning resistance and it displayed stronger inhibition of lipid peroxidation and of colon cancer cell growth by MTT assay, compared to chlorogenic acid. Therefore, this study may expand the industrial applications of chlorogenic acid as water-soluble or browning resistant compound (CHG) through enzymatic glycosylation

Strain mediated phase crossover in Ruddlesden Popper nickelates

Recent progress on the signatures of pressure-induced high temperature superconductivity in Ruddlesden Popper (RP) nickelates (Lan+1NinO3n+1) has attracted growing interest in both theoretical calculations and experimental efforts. The fabrication of high-quality single crystalline RP nickelate thin films is critical for possible reducing the superconducting transition pressure and advancing applications in microelectronics in the future. In this study, we report the observations of an active phase transition in RP nickelate films induced by misfit strain. We found that RP nickelate films favor the perovskite structure (n = infinite) under tensile strains, while compressive strains stabilize the La3Ni2O7 (n = 2) phase. The selection of distinct phases is governed by the strain dependent formation energy and electronic configuration. In compressively strained La3Ni2O7, we experimentally determined splitting energy is ~0.2 eV and electrons prefer to occupy in-plane orbitals. First principles calculations unveil a robust coupling between strain effects and the valence state of Ni ions in RP nickelates, suggesting a dual driving force for the inevitable phase co-existence transition in RP nickelates. Our work underscores the sensitivity of RP nickelate formation to epitaxial strain, presenting a significant challenge in fabricating pure-phase RP nickelate films. Therefore, special attention to stacking defects and grain boundaries between different RP phases is essential when discussing the pressure-induced superconductivity in RP nickelates.Comment: 29 pages, 5 figures, one supplementary material

Herb Mixture Inhibits Proinflammatory Mediators Through the Suppression of JNK and P38 Activation in LPS-Stimulated Raw 264.7 Macrophages

ABSTRACT Inflammation has been implicated as a pathophysiological feature underlying many chronic diseases. In the present study, we investigated the anti-inflammatory effect of new formulation of herb medicine, DG1102, composed by five different herbal ingredients such as Taraxaci Herba, Rhei Rhizoma, Houttuynia cordata Thunb. Houttuyniae Herba, Eriobotryae Folium which has been used for inflammatory diseases, in LPS-stimulated Raw 264.7 macrophages. DG1102 suppressed nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1α, IL-6, IL-10 and macrophage inflammatory protein production in the lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, as well as inducible nitric oxide synthase and cyclooxygenase 2 expression. Furthermore, DG1102 suppressed the activation of p38 and c-Jun N-terminal kinase (JNK). Our results suggest that DG1102 has an immune-modulatory activity suppressing production of pro-inflammatory cytokines and chemokine via the suppression of JNK and p38 MAPK activation in LPS-stimulated RAW 264.7 macrophages. The present study provides the biological evidence of the efficacy of medicinal plants in the treatment of inflammatory diseases

Electrical and optical properties of VO2 polymorphic epitaxial filMaster

Vanadium dioxide (VO2) polymorphs have many interesting physical and chemical properties that are crystal-structure dependent. We report that polymorphic (010)VO2(M1), (100)VO2(A), and (100)VO2(B) can be epitaxially grown on (001), (011), and (111) orient-ed Y-stabilized ZrO2 (YSZ), respectively. Although VO2(M1) exhibits a typical metal–insulator transition near 68°C, and VO2(B) behaves as an insulator. And, the resistivity of VO2(A) is three orders of magnitude lower than that of (100)VO2(A) epitaxial filMaster previ-ously grown on (011)SrTiO3. Ellipsometry reveals that the bandgap of VO2(A) also de-creases. Each type of VO2 polymorphic film grown on cost-effective YSZ will be of great interest for numerous electronic and energy applications.|바나듐 이산화물(VO2)은 결정 구조에 따라서 다양한 전기적, 광학적 특성을 보인다. 하지만, 단결정을 만들기 어렵기 때문에 VO2의 본질적인 특성을 연구하는데 제약이 있었다. 우리는 에피 증착법을 이용하여 (001)-, (011)-, (111)-방향의 지르코늄 이산화물(Y-stabilized ZrO2, YSZ) 기판위에 VO2(M1), VO2(A), VO2(B)를 각각 성장하는데 성공하였다. 엑스선 회절기와 전자 투과 현미경을 이용하여 박막의 구조와 결정성을 확인했으며 에피 성장에 대한 박막과 기판 면의 조화를 확인했다. 온도 증가에 따라 VO2(M1)이 68oC 에서 비금속-금속으로 전이하는 특성과 VO2(A)와 VO2(B)가 저항이 단순 증가하는 특성을 관찰하였다. 흥미롭게도 YSZ 위에 에피 증착된 VO2(A)는 SrTiO3 위에 증착된 기존의 에피 박막에 비해서 저항이 1000배 감소하였다. 타원 편광계를 이용하여 순수한 상 각각의 띠틈(bandgap)을 측정하고 전자구조를 제안하였다. 저렴한 YSZ 위의 각각 에피 성장된 VO2 동질이상체에 대한 우리의 연구는 차세대 전자소자와 에너지 응용에 큰 흥미를 끌 것이다.openⅠ. Introduction 1 1.1 General overview of VO2 polymorphs 1 1.2 Epitaxial stabilization of pure VO2 polymorphic phases 2 1.3 Y-stabilized ZrO2 (YSZ): a new substrate for epitaxial growth of pure VO2(M1), VO2(A), and VO2(B) 3 Ⅱ. Experimental Methods 4 2.1 Thin film deposition 4 2.2 Characterization 4 Ⅲ. Results and Discussion 6 3.1 VO2(M1) epitaxial filMaster on (001)YSZ 6 3.2 VO2(A) epitaxial filMaster on (011)YSZ 11 3.3 VO2(B) epitaxial filMaster on (111)YSZ 14 3.4 Electrical properties of pure VO2(M1), VO2(A), and VO2(B) 16 3.5 Optical properties of pure VO2(M1), VO2(A), and VO2(B) 18 Ⅳ. Conclusion 20MASTERdCollectio

Physical Properties of Vanadium Wadsley Phases and Application for Infrared Transparent Conductor

vanadium dioxide polymorphs; VO2(A); VO2(B); VO2(M) vanadium Wadsley phase (VmO2m+1); VO2; V6O13; V2O5; electronic band structure; infrared transparent conductor.DoctordCollectio

Sharp contrast in the electrical and optical properties of vanadium Wadsley (VmO2m+1, m > 1) epitaxial films selectively stabilized on (111)-oriented Y-stabilized ZrO2

Four oxidation states (V2+, V3+, V4+, and V5+) in vanadium oxides and the conversion between them have attracted attention for application to batteries and electronics. Compared to single-valence counterparts, however, there have been few reports on the fundamental properties of mixed-valence vanadium oxide films, as their complexity and closeness in thermodynamic phase diagrams hinder the formation of pure phases in film. Here, using an epitaxial growth technique with precise control of oxygen partial pressure (20-100 mTorr) on (111)-oriented Y-stabilized ZrO2, we selectively stabilize pure phases of VO2(B) (m = infinity), V6O13 (m = 6), and V2O5 (m = 2), so-called Wadsley phases (VmO2m+1, m > 1) in which V4+ and/or V5+ can coexist. Fractional increase of V4+ changes the electrical ground state, insulating VO2 (B) and V2O5, metallic V6O13 transition into insulators below 150 K. While VO2 (B) and V(6)O(13 )exhibit strong spectral weights at low photon energy in the room-temperature extinction coefficients, the band-edge absorption shifts toward higher photon energy for smaller m, opening an indirect band gap of 2.6 eV in V2O5 . The sharp contrast of electrical and optical properties between vanadium Wadsley phases highlights the importance of precisely controlling the oxidation state of vanadium. ©2019 American Physical Societ

Immune-Modulating Lipid Nanomaterials for the Delivery of Biopharmaceuticals

In recent years, with the approval of preventative vaccines for pandemics, lipid nanoparticles have become a prominent RNA delivery vehicle. The lack of long-lasting effects of non-viral vectors is an advantage for infectious disease vaccines. With the introduction of microfluidic processes that facilitate the encapsulation of nucleic acid cargo, lipid nanoparticles are being studied as delivery vehicles for various RNA-based biopharmaceuticals. In particular, using microfluidic chip-based fabrication processes, nucleic acids such as RNA and proteins can be effectively incorporated into lipid nanoparticles and utilized as delivery vehicles for various biopharmaceuticals. Due to the successful development of mRNA therapies, lipid nanoparticles have emerged as a promising approach for the delivery of biopharmaceuticals. Biopharmaceuticals of various types (DNA, mRNA, short RNA, proteins) possess expression mechanisms that are suitable for manufacturing personalized cancer vaccines, while also requiring formulation with lipid nanoparticles. In this review, we describe the basic design of lipid nanoparticles, the types of biopharmaceuticals used as carriers, and the microfluidic processes involved. We then present research cases focusing on lipid-nanoparticle-based immune modulation and discuss the current status of commercially available lipid nanoparticles, as well as future prospects for the development of lipid nanoparticles for immune regulation purposes

High infrared transparency up to 8-micrometer-wavelength in correlated vanadium Wadsley conductors

Within industrial and military contexts, research on infrared transparent conductors (IR-TCs) has been limited due to the significant suppression of transparency by the free electron response. In this paper, we report that strong correlations between electrons play an important role in the development of a new strategy for fabricating IR-TCs. Metallic VO2(B) and V6O13 persistently exhibit transmittances 45% higher than that of Sn-doped In2O3 for a broad IR wavelength range of up to 8 μm. Based on electronic band structures determined quantitatively using x-ray absorption spectroscopy, x-ray photoemission spectroscopy, and spectroscopic ellipsometry, we propose that the enhancement in the IR-TC is attributed to the redshift of the plasma frequency induced by the correlated electrons. © 2020 Author(s).1

Degradation Mechanism of Vanadium Oxide Films When Grown on Y‐Stabilized ZrO 2

Although vanadium oxide (VOx) phases are thermodynamically similar, Y-stabilized ZrO2 (YSZ) substrates show selective growth as single-crystalline films. However, in this study, we find that the films degrade with the formation of nanoislands when evaporating VOx onto YSZ at a substrate temperature >500 °C. The nanoislands are epitaxial, i.e., Y-doped VO2(R) at an oxygen partial pressure (Formula presented.) < 30 mTorr, and YVO4 at (Formula presented.) > 50 mTorr. Energy-dispersive X-ray spectroscopy shows that the rapid diffusion of vanadium and yttrium plays a critical role in film degradation. The degradation mechanism revealed herein guides the fabrication of VOx films for energy and electronic device applications. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim1