Structural change in polar nanoregion in alkali niobate added Pb(Zn <inf>1/3</inf>Nb <inf>2/3</inf>) <inf>0.95</inf>Ti <inf>0.05</inf>O <inf>3</inf> single crystal and its effect on ferroelectric properties

Pb(Zn 1/3Nb 2/3) 0.95Ti 0.05O 3 (PZNT) single crystals with 5 mol.% alkali niobate such as LiNbO 3 (LN), NaNbO 3 (NN), and KNbO 3 (KN) were fabricated by using a flux method to investigate the effect of A-site cation radius on the structure and ferroelectric properties of PZNT under electric field (E-field). Their structure and properties showed different electric field dependence. Polarization versus electric field and strain versus electric field curves of PZNT-0.05LN showed E-field induced phase transition from a relaxor state to a normal ferroelectric state. However, only relaxor behavior was observed in PZNT-0.05NN and PZNT-0.05KN. The effect of A-site ion doping is attributed to the change in local lattice distortion and polar nano-region. When smaller cation such as Li ion substitutes Pb ion, the off-center displacement of Nb ion stabilizes rhombohedral lattice distortion. They, in turn, facilitate the development of macro-domains under electric field (E-field) in PZNT-0.05LN. In contrast, the substitution of Pb with larger cations such as Ni and K decreases the rhombohedral distortion of PZNT, which leads to the disappearance of unique E-field induced phase transition from rhombohedral to tetragonal phase in PZNT. Therefore, non-linear electrostrictive behavior of relaxor ferroelectrics is found in PZNT-0.05NN and PZNT-0.05KN. © 2012 American Institute of Physics

Subthreshold characteristics of pentacene field-effect transistors influenced by grain boundaries

Grain boundaries in polycrystalline pentacene films significantly affect the electrical characteristics of pentacene field-effect transistors (FETs). Upon reversal of the gate voltage sweep direction, pentacene FETs exhibited hysteretic behaviours in the subthreshold region, which was more pronounced for the FET having smaller pentacene grains. No shift in the flat-band voltage of the metal-insulator-semiconductor capacitor elucidates that the observed hysteresis was mainly caused by the influence of localized trap states existing at pentacene grain boundaries. From the results of continuous on/off switching operation of the pentacene FETs, hole depletion during the off period is found to be limited by pentacene grain boundaries. It is suggested that the polycrystalline nature of a pentacene film plays an important role on the dynamic characteristics of pentacene FETs

Silicon-based III-V quantum-dot laser for silicon photonics

Monolithic III-V materials grown on Si is a promising platform for silicon photonics. Here, by investigating the laser performance of two conventional III-V quantum structures on Si, namely quantumdots and quantum-well, we unambiguously demonstrate the excellence and suitability of quantum-dots over quantum-well in silicon-based laser structure and reveal the physical mechanisms underneath, which is attributed to the better tolerance characteristic of quantum-dots for optically detrimental defects. Our work shows that monolithic III-V quantum-dot lasers on Si are the most promising light source for silicon photonics technology

miR-93/miR-106b/miR-375-CIC-CRABP1: a novel regulatory axis in prostate cancer progression

Capicua (CIC) has been implicated in pathogenesis of spinocerebellar ataxia type-1 (SCA1) neurodegenerative disease and some types of cancer; however, the role of CIC in prostate cancer remains unknown. Here we show that CIC suppresses prostate cancer progression. CIC expression was markedly decreased in human prostatic carcinoma. CIC overexpression suppressed prostate cancer cell proliferation, invasion, and migration, whereas CIC RNAi exerted opposite effects. We found that knock-down of CIC derepresses expression of ETV5 and CRABP1 in LNCaP and PC-3 cells, respectively, thereby promoting cell proliferation and invasion. We also discovered that miR-93, miR-106b, and miR-375, which are known to be frequently overexpressed in prostate cancer patients, cooperatively down-regulate CIC levels to promote cancer progression. Altogether, we suggest miR-93/miR-106b/miR-375-CIC-CRABP1 as a novel key regulatory axis in prostate cancer progression.113324Ysciescopu

Synthesis and NOx removal performance of anatase S-TiO2/g-CN heterojunction formed from dye wastewater sludge.

In this study, sludges generated from Ti-based flocculation of dye wastewater were used to retrieve photoactive titania (S-TiO2). It was heterojunctioned with graphitic carbon nitride (g-CN) to augment photoactivity under UV/visible light irradiance. Later the as-prepared samples were utilized to remove nitrogen oxides (NOx) in the atmospheric condition through photocatalysis. Heterojunction between S-TiO2 and g-CN was prepared through facile calcination (@550 °C) of S-TiO2 and melamine mix. Advanced sample characterization was carried out and documented extensively. Successful heterojunction was confirmed from the assessment of morphological and optical attributes of the samples. Finally, the prepared samples' level of photoactivity was assessed through photooxidation of NOx under both UV and visible light irradiance. Enhanced photoactivity was observed in the prepared samples irrespective of the light types. After 1 h of UV/visible light-based photooxidation, the best sample STC4 was found to remove 15.18% and 9.16% of atmospheric NO, respectively. In STC4, the mixing ratio of S-TiO2, to melamine was maintained as 1:3. Moreover, the optical bandgap of STC4 was found as 2.65 eV, where for S-TiO2, it was 2.83 eV. Hence, the restrained rate of photogenerated charge recombination and tailored energy bandgap of the as-prepared samples were the primary factors for enhancing photoactivity

Latent tuberculosis infection screening and treatment in congregate settings (TB FREE COREA): protocol for a prospective observational study in Korea

IntroductionSouth Korea regards tuberculosis (TB) incidence in congregate settings as a serious problem. To this end, systematic latent TB infection (LTBI) diagnosis and treatment were provided to approximately 1.2 million individuals in high-risk congregate settings.Methods and analysisWe designed a prospective cohort study of individuals tested for LTBI, based on the data collected on all persons screened for LTBI as part of the 2017 congregate settings programme in South Korea. Four types of databases are kept: LTBI screening database (personal information and LTBI test results), national health information (NHI) database (socio-demographic data and comorbidities), public healthcare information system (PHIS) database, and the Korean national TB surveillance system database (TB outcomes). Information regarding LTBI treatment at private hospitals and public health centres is collected from NHI and PHIS databases, respectively. The screening data are cleaned, duplicates are removed, and, where appropriate, re-coded to analyse specific exposures and outcomes. The primary objective is to compare the number of active TB cases prevented within 2 years between participants undergoing treatment and not undergoing treatment in the LTBI screening programme in congregate settings. Cascade of care for LTBI diagnosis and treatment will be evaluated among those with a positive LTBI test result. A Cox proportional hazards model will be applied to determine the risk factors for developing active TB.Ethics and disseminationThe protocol is approved by the institutional review boards of Incheon St. Mary’s Hospital, the Catholic University of Korea. Study results will be disseminated through peer-reviewed journals and conference presentations.Trial registration numberKCT000390

Single-mode photonic crystal nanobeam lasers monolithically grown on Si for dense integration

Ultra-compact III-V nanolasers monolithically integrated on Si with ultra-low energy consumption and small modal volume have been emerged as one of the most promising candidates to achieve Si on-chip light sources. However, the significant material dissimilarities between III-V and Si fundamentally limit the performance of Si-based III-V nanolasers. In this work, we report 1.3 m InAs/GaAs quantum-dot photonic-crystal (PhC) nanobeam lasers directly grown on complementary metal-oxide-semiconductor compatible on-axis Si (001) substrates. The continuous-wave optically pumped PhC nanobeam lasers exhibited a single-mode operation, with an ultra-low lasing threshold of ~ 0.8 W at room temperature. In addition, a nanoscale physical volume of ~ 8 0.53 0.36 m3 (~ 25 (n1)3) was realized through a small number of air-holes in PhC nanobeam laser. The promising characteristics of the PhC nanobeam lasers with small footprint and ultra-low energy consumption show their advanced potential towards densely integrated Si photonic integrated circuits

Quantum spin liquid states in the two dimensional kagome antiferromagnets, ZnxCu4-x(OD)6Cl2

A three-dimensional system of interacting spins typically develops static long-range order when it is cooled. If the spins are quantum (S = 1/2), however, novel quantum paramagnetic states may appear. The most highly sought state among them is the resonating valence bond (RVB) state in which every pair of neighboring quantum spins form entangled spin singlets (valence bonds) and the singlets are quantum mechanically resonating amongst all the possible highly degenerate pairing states. Here we provide experimental evidence for such quantum paramagnetic states existing in frustrated antiferromagnets, ZnxCu4-x(OD)6Cl2, where the S = 1/2 magnetic Cu2+ moments form layers of a two-dimensional kagome lattice. We find that in Cu4(OD)6Cl2, where distorted kagome planes are weakly coupled to each other, a dispersionless excitation mode appears in the magnetic excitation spectrum below ~ 20 K, whose characteristics resemble those of quantum spin singlets in a solid state, known as a valence bond solid (VBS), that breaks translational symmetry. Doping nonmagnetic Zn2+ ions reduces the distortion of the kagome lattice, and weakens the interplane coupling but also dilutes the magnetic occupancy of the kagome lattice. The VBS state is suppressed and for ZnCu3(OD)6Cl2 where the kagome planes are undistorted and 90% occupied by the Cu2+ ions, the low energy spin fluctuations in the spin liquid phase become featureless

DNA end recognition by the Mre11 nuclease dimer: insights into resection and repair of damaged DNA

The Mre11-Rad50-Nbs1 (MRN) complex plays important roles in sensing DNA damage, as well as in resecting and tethering DNA ends, and thus participates in double-strand break repair. An earlier structure of Mre11 bound to a short duplex DNA molecule suggested that each Mre11 in a dimer recognizes one DNA duplex to bridge two DNA ends at a short distance. Here, we provide an alternative DNA recognition model based on the structures of Methanococcus jannaschii Mre11 (MjMre11) bound to longer DNA molecules, which may more accurately reflect a broken chromosome. An extended stretch of B-form DNA asymmetrically runs across the whole dimer, with each end of this DNA molecule being recognized by an individual Mre11 monomer. DNA binding induces rigid-body rotation of the Mre11 dimer, which could facilitate melting of the DNA end and its juxtaposition to an active site of Mre11. The identified Mre11 interface binding DNA duplex ends is structurally conserved and shown to functionally contribute to efficient resection, non-homologous end joining, and tolerance to DNA-damaging agents when other resection enzymes are absent. Together, the structural, biochemical, and genetic findings presented here offer new insights into how Mre11 recognizes damaged DNA and facilitates DNA repair.X111513Ysciescopu