Phospholipase Cγ1 (PLCγ1) controls osteoclast numbers via colony-stimulating factor 1 (CSF-1)-dependent diacylglycerol/β-catenin/cyclinD1 pathway

Phospholipases Cγ (PLCγ) 1 and 2 are a class of highly homologous enzymes modulating a variety of cellular pathways through production of inositol 1,4,5-trisphosphate and diacylglycerol (DAG). Our previous studies demonstrated the importance of PLCγ2 in osteoclast (OC) differentiation by modulating inositol 1,4,5-trisphosphate-mediated calcium oscillations and the up-regulation of the transcription factor NFATc1. Surprisingly, despite being expressed throughout osteoclastogenesis, PLCγ1 did not compensate for PLCγ2 deficiency. Because both isoforms are activated during osteoclastogenesis, it is plausible that PLCγ1 modulates OC development independently of PLCγ2. Here, we utilized PLCγ1-specific shRNAs to delete PLCγ1 in OC precursors derived from wild type (WT) mice. Differently from PLCγ2, we found that PLCγ1 shRNA significantly suppresses OC differentiation by limiting colony-stimulating factor 1 (CSF-1)-dependent proliferation and β-catenin/cyclinD1 levels. Confirming the specificity toward CSF-1 signaling, PLCγ1 is recruited to the CSF-1 receptor following exposure to the cytokine. To understand how PLCγ1 controls cell proliferation, we turned to its downstream effector, DAG. By utilizing cells lacking the DAG kinase ζ, which have increased DAG levels, we demonstrate that DAG modulates CSF-1-dependent proliferation and β-catenin/cyclinD1 levels in OC precursors. Most importantly, the proliferation and osteoclastogenesis defects observed in the absence of PLCγ1 are normalized in PLCγ1/DAG kinase ζ double null cells. Taken together, our study shows that PLCγ1 controls OC numbers via a CSF-1-dependent DAG/β-catenin/cyclinD1 pathway

Structural Stability of Lexical Semantic Spaces: Nouns in Chinese and French

Many studies in the neurosciences have dealt with the semantic processing of words or categories, but few have looked into the semantic organization of the lexicon thought as a system. The present study was designed to try to move towards this goal, using both electrophysiological and corpus-based data, and to compare two languages from different families: French and Mandarin Chinese. We conducted an EEG-based semantic-decision experiment using 240 words from eight categories (clothing, parts of a house, tools, vehicles, fruits/vegetables, animals, body parts, and people) as the material. A data-analysis method (correspondence analysis) commonly used in computational linguistics was applied to the electrophysiological signals. The present cross-language comparison indicated stability for the following aspects of the languages' lexical semantic organizations: (1) the living/nonliving distinction, which showed up as a main factor for both languages; (2) greater dispersion of the living categories as compared to the nonliving ones; (3) prototypicality of the \emph{animals} category within the living categories, and with respect to the living/nonliving distinction; and (4) the existence of a person-centered reference gradient. Our electrophysiological analysis indicated stability of the networks at play in each of these processes. Stability was also observed in the data taken from word usage in the languages (synonyms and associated words obtained from textual corpora).Comment: 17 pages, 4 figure

Electronic device fabrication and characterization based on two-dimensional materials

Two-dimensional (2D) materials have attracted extensive attention due to their unique and remarkable properties, such as the atomically thin body, pristine surface free of dangling bonds, tunable bandgap, and reasonably high mobility, which make 2D materials promising candidates for novel electronic and optoelectronic devices in low power, high performance and flexible applications. In this thesis, the optical and electrical properties of MoS2/WS2 heterostructures grown by chemical vapor deposition (CVD) are studied. By using Raman spectra, photoluminescence (PL) spectra and atomic force microscopy (AFM), the vertical and lateral MoS2/WS2 structures are identified. The transistors and Hall-bar devices based on vertical monolayer-MoS2/monolayer-WS2 heterostructures are successfully fabricated. The devices show typical n-channel characteristics, indicating that MoS2 and WS2 are naturally n-type doped. Due to the type II band alignment and sharp interface, these vertical and lateral MoS2/WS2 heterostructures can potentially be used for tunneling field-effect transistors and high-speed photodetectors. In addition, the crystal orientation and electronic transport in germanium selenide (GeSe) are also studied. The crystallographic direction of the GeSe is determined by angle-resolved polarized Raman measurement. The anisotropic electronic transport of the GeSe is measured by angle-resolved DC electrical conductance. The results indicate that GeSe has a prominent anisotropic electronic transport with maximum conductance likely along the armchair direction. The anisotropic conductance in GeSe may enable a new series of electronic and optoelectronic devices such as plasmonic devices with resonance frequency continuously tunable with light polarization direction, and high-efficiency thermoelectric devices. In summary, the MoS2/WS2 heterostructures and anisotropic electronic transport in GeSe have been studied. The knowledge gained in these projects will be essential for designing and fabricating novel electronic devices based on these materials in the future

Numerical proper reparametrization of space curves and surfaces

Simplifying rational parametrizations of surfaces is a basic problem in CAD (computer-aided design). One important way is to reduce their tracing index, called proper reparametrization. Most existing proper reparametrization work is symbolic, yet in practical environments the surfaces are usually given with perturbed coefficients hence need a numerical technique of reparametrization considering the intrinsic properness of the perturbed surfaces. We present algorithms for reparametrizing a numerically rational space curve or surface. First, we provide an efficient way to find a parametric support transformation and compute a reparametrization with proper parametric support. Second, we develop a numerical algorithm to further reduce the tracing index, where numerical techniques such as sparse interpolation and approximated GCD computations are involved. We finally provide the error bound between the given rational curve/surface and our reparametrization result.Ministerio de Ciencia, Innovación y Universidade