Two-dimensional structures of ferroelectric domain inversion in LiNbO3 by direct electron beam lithography

We report on the fabrication of domain-reversed structures in LiNbO3 by means of direct electron beam lithography at room temperature without any static bias. The LiNbO3 crystals were chemically etched after the exposure of electron beam and then, the patterns of domain inversion were characterized by atomic force microscopy (AFM). In our experiment, an interesting phenomenon occurred when the electron beam wrote a one-dimensional (1-D) grating on the negative c-face: a two-dimensional (2-D) dotted array was observed on the positive c- face, which is significant for its potential to produce 2-D and three-dimensional photonic crystals. Furthermore, we also obtained 2-D ferroelectric domain inversion in the whole LiNbO3 crystal by writing the 2-D square pattern on the negative c-face. Such a structure may be utilized to fabricate 2-D nonlinear photonic crystal. AFM demonstrates that a 2-D domain-reversed structure has been achieved not only on the negative c-face of the crystal, but also across the whole thickness of the crystal.Comment: 17 pages, 4 figure

Do mutual funds have consistency in their performance?

Using a comprehensive data set of 714 Chinese mutual funds from 2004 to 2015, the study investigates these funds’ performance persistence by using the Capital Asset Pricing model, the Fama-French three-factor model and the Carhart Four-factor model. For persistence analysis, we categorize mutual funds into eight octiles based on their one year lagged performance and then observe their performance for the subsequent 12 months. We also apply Cross-Product Ratio technique to assess the performance persistence in these Chinese funds. The study finds no significant evidence of persis- tence in the performance of the mutual funds. Winner (loser) funds do not continue to be winner (loser) funds in the subsequent time period. These findings suggest that future performance of funds cannot be predicted based on their past performance.info:eu-repo/semantics/publishedVersio

Acoustic phonon recycling for photocarrier generation in graphene-WS_{2} heterostructures

Electron-phonon scattering is the key process limiting the efficiency of modern nanoelectronic and optoelectronic devices, in which most of the incident energy is converted to lattice heat and finally dissipates into the environment. Here, we report an acoustic phonon recycling process in graphene-WS_{2} heterostructures, which couples the heat generated in graphene back into the carrier distribution in WS_{2}. This recycling process is experimentally recorded by spectrally resolved transient absorption microscopy under a wide range of pumping energies from 1.77 to 0.48 eV and is also theoretically described using an interfacial thermal transport model. The acoustic phonon recycling process has a relatively slow characteristic time (>100 ps), which is beneficial for carrier extraction and distinct from the commonly found ultrafast hot carrier transfer (~1 ps) in graphene-WS_{2} heterostructures. The combination of phonon recycling and carrier transfer makes graphene-based heterostructures highly attractive for broadband high-efficiency electronic and optoelectronic applications

HIT: linking herbal active ingredients to targets

The information of protein targets and small molecule has been highly valued by biomedical and pharmaceutical research. Several protein target databases are available online for FDA-approved drugs as well as the promising precursors that have largely facilitated the mechanistic study and subsequent research for drug discovery. However, those related resources regarding to herbal active ingredients, although being unusually valued as a precious resource for new drug development, is rarely found. In this article, a comprehensive and fully curated database for Herb Ingredients’ Targets (HIT, http://lifecenter.sgst.cn/hit/) has been constructed to complement above resources. Those herbal ingredients with protein target information were carefully curated. The molecular target information involves those proteins being directly/indirectly activated/inhibited, protein binders and enzymes whose substrates or products are those compounds. Those up/down regulated genes are also included under the treatment of individual ingredients. In addition, the experimental condition, observed bioactivity and various references are provided as well for user's reference. Derived from more than 3250 literatures, it currently contains 5208 entries about 1301 known protein targets (221 of them are described as direct targets) affected by 586 herbal compounds from more than 1300 reputable Chinese herbs, overlapping with 280 therapeutic targets from Therapeutic Targets Database (TTD), and 445 protein targets from DrugBank corresponding to 1488 drug agents. The database can be queried via keyword search or similarity search. Crosslinks have been made to TTD, DrugBank, KEGG, PDB, Uniprot, Pfam, NCBI, TCM-ID and other databases

Roll motion compensation by active marine gyrostabiliser

Unmanned Surface Vehicle (USV) has been gaining more marine applications nowadays. However, the USV is vulnerable to excessive rolling motions induced by water waves, and this phenomenon may cause significant downtime to the operations of USV and engender detrimental effects to the on-board instrument and sensors. Active control system had been proposed to compensate the rolling stability issue but most of the proposed devices were expensive. This paper developed a gyrostabiliser on USV model to compensate the excessive rolling motion. Gyrostabiliser consists of rotor, gimbal and spinning axes, which commonly used for measuring or maintaining orientations and angular velocities. The gyrostabiliser was mounted vertically inside the USV model. Experiments were conducted to obtain the ideal gains of gyrostabiliser’s controller, to investigate the differences between active- and passive-gyrostabiliser, and to identify the induced pitch effect of the vertical gyrostabiliser to the USV model. The roll angle of the USV was measured by gyro sensor, whereas the precession motor and flywheel motor were controlled by a non-encoder Direct-Current (DC) motor. A proportional controller of the gyrostabiliser was implemented through Arduino Integrated Development Environment (IDE) to ensure optimal performance of gyrostabiliser in precession speed and direction control. The results showed that both active- and passive-gyrostabiliser managed to mitigate the roll angle of USV from +/- 15° back to less than 1° and reached steady state within 2.32 seconds and 2.60 seconds, respectively. The active gyrostabiliser had advantage to return to zero precession angle while the passive gyrostabiliser accumulated 30° precession angle in the experiment. The induced pitch angle by the gyrostabiliser had been found in an insignificant magnitude for the case study. The outcomes of this paper lead to an alternative for improving the robustness of USV in rolling reduction. 

Sufficient Covariate, Propensity Variable and Doubly Robust Estimation

Statistical causal inference from observational studies often requires adjustment for a possibly multi-dimensional variable, where dimension reduction is crucial. The propensity score, first introduced by Rosenbaum and Rubin, is a popular approach to such reduction. We address causal inference within Dawid's decision-theoretic framework, where it is essential to pay attention to sufficient covariates and their properties. We examine the role of a propensity variable in a normal linear model. We investigate both population-based and sample-based linear regressions, with adjustments for a multivariate covariate and for a propensity variable. In addition, we study the augmented inverse probability weighted estimator, involving a combination of a response model and a propensity model. In a linear regression with homoscedasticity, a propensity variable is proved to provide the same estimated causal effect as multivariate adjustment. An estimated propensity variable may, but need not, yield better precision than the true propensity variable. The augmented inverse probability weighted estimator is doubly robust and can improve precision if the propensity model is correctly specified

Roll motion compensation by active marine gyrostabiliser

922-929Unmanned Surface Vehicle (USV) has been gaining more marine applications nowadays. However, the USV is vulnerable to excessive rolling motions induced by water waves, and this phenomenon may cause significant downtime to the operations of USV and engender detrimental effects to the on-board instrument and sensors. Active control system had been proposed to compensate the rolling stability issue but most of the proposed devices were expensive. This paper developed a gyrostabiliser on USV model to compensate the excessive rolling motion. Gyrostabiliser consists of rotor, gimbal and spinning axes, which commonly used for measuring or maintaining orientations and angular velocities. The gyrostabiliser was mounted vertically inside the USV model. Experiments were conducted to obtain the ideal gains of gyrostabiliser’s controller, to investigate the differences between active- and passive-gyrostabiliser, and to identify the induced pitch effect of the vertical gyrostabiliser to the USV model. The roll angle of the USV was measured by gyro sensor, whereas the precession motor and flywheel motor were controlled by a non-encoder Direct-Current (DC) motor. A proportional controller of the gyrostabiliser was implemented through Arduino Integrated Development Environment (IDE) to ensure optimal performance of gyrostabiliser in precession speed and direction control. The results showed that both active- and passive-gyrostabiliser managed to mitigate the roll angle of USV from +/- 15° back to less than 1° and reached steady state within 2.32 seconds and 2.60 seconds, respectively. The active gyrostabiliser had advantage to return to zero precession angle while the passive gyrostabiliser accumulated 30° precession angle in the experiment. The induced pitch angle by the gyrostabiliser had been found in an insignificant magnitude for the case study. The outcomes of this paper lead to an alternative for improving the robustness of USV in rolling reduction

HMGB1 in health and disease

Complex genetic and physiological variations as well as environmental factors that drive emergence of chromosomal instability, development of unscheduled cell death, skewed differentiation, and altered metabolism are central to the pathogenesis of human diseases and disorders. Understanding the molecular bases for these processes is important for the development of new diagnostic biomarkers, and for identifying new therapeutic targets. In 1973, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and termed high-mobility group (HMG) proteins. The HMG proteins include three superfamilies termed HMGB, HMGN, and HMGA. High-mobility group box 1 (HMGB1), the most abundant and well-studied HMG protein, senses and coordinates the cellular stress response and plays a critical role not only inside of the cell as a DNA chaperone, chromosome guardian, autophagy sustainer, and protector from apoptotic cell death, but also outside the cell as the prototypic damage associated molecular pattern molecule (DAMP). This DAMP, in conjunction with other factors, thus has cytokine, chemokine, and growth factor activity, orchestrating the inflammatory and immune response. All of these characteristics make HMGB1 a critical molecular target in multiple human diseases including infectious diseases, ischemia, immune disorders, neurodegenerative diseases, metabolic disorders, and cancer. Indeed, a number of emergent strategies have been used to inhibit HMGB1 expression, release, and activity in vitro and in vivo. These include antibodies, peptide inhibitors, RNAi, anti-coagulants, endogenous hormones, various chemical compounds, HMGB1-receptor and signaling pathway inhibition, artificial DNAs, physical strategies including vagus nerve stimulation and other surgical approaches. Future work further investigating the details of HMGB1 localization, structure, post-translational modification, and identification of additional partners will undoubtedly uncover additional secrets regarding HMGB1\u27s multiple functions. (C) 2014 Elsevier Ltd. All rights reserved