A bootstrap-based regression method for comprehensive discovery of differential gene expressions: An application to the osteoporosis study

A common purpose of microarray experiments is to study the variation in gene expression across the categories of an experimental factor such as tissue types and drug treatments. However, it is not uncommon that the studied experimental factor is a quantitative variable rather than categorical variable. Loss of information would occur by comparing gene-expression levels between groups that are factitiously defined according to the quantitative threshold values of an experimental factor. Additionally, lack of control for some sensitive clinical factors may bring serious false positive or negative findings.In the present study, we described a bootstrap-based regression method for analyzing gene-expression data from the non-categorical microarray experiments. To illustrate the utility of this method, we applied it to our recent gene-expression study of circulating monocytes in subjects with a wide range of variations in bone mineral density (BMD). This method allows a comprehensive discovery of gene expressions associated with osteoporosis-related traits while controlling other common confounding factors such as height, weight and age. Several genes identified in our study are involved in osteoblast and osteoclast functions and bone remodeling and/or menopause-associated estrogen-dependent pathways, which provide important clues to understand the etiology of osteoporosis. Availability: SAS code is available from the authors upon request. © 2011 Elsevier Masson SAS.postprin

Passivation of Oxide Traps and Interface States in GaAs Metal-Oxide-Semiconductor Capacitor by LaTaON Passivation Layer and Fluorine Incorporation

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Passivation of oxide traps in gallium arsenide (semiconductor) metal-oxide-semiconductor capacitor with high-k dielectric by using fluorine incorporation

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Boundary recovery for 3D Delaunay triangulation

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Improved performance of pentacene OTFTs with HfLaO gate dielectric by using fluorination and nitridation

Pentacene organic thin-film transistors (OTFTs) with fluorinated high-κ HfLaO as gate insulator were fabricated. The dielectrics were prepared by sputtering method and then annealed in N 2 or NH 3 at 400 °C. Subsequently, the dielectrics were treated by fluorine plasma for different durations (100, 300, and 900 s). The N 2 and NH 3-annealed OTFTs with a 100-s plasma treatment achieve a carrier mobility of 0.62 and 0.66 cm 2V̇s, respectively, which are higher than those of the OTFTs without plasma treatment (0.22 and 0.41 cm 2V̇s). Moreover, the plasma-treated OTFTs realize better 1/f noise characteristics than those without plasma treatment. The improved performance is due to passivation of the dielectric surface by plasma-induced fluorine incorporation. However, for longer time (300 and 900 s) of plasma treatment, the performance of the OTFTs deteriorates in terms of carrier mobility and 1/f noise characteristics due to increased plasma-induced damage of the dielectric surface. The morphology of the pentacene film grown on the HfLaO gate insulator was characterized by SEM. It reveals that the pentacene film has larger grain size and smoother surface on the HfLaO dielectric (for both annealing gases) with 100-s plasma treatment than the others (0, 300, and 900 s). Finally, AFM characterization of the HfLaO film also confirms the damaging effect of excessive plasma treatment on the dielectric. © 2012 IEEE.published_or_final_versio

Low-voltage polymer thin-film transistors with high-k HfTiO gate dielectric annealed in NH3 or N2

OTFTs with P3HT as organic semiconductor and HfTiO as gate dielectric have been studied in this work. The HfTiO dielectric film was prepared by RF sputtering of Hf and DC sputtering of Ti at room temperature. Subsequently, the dielectric film was annealed in an NH3 or N2 ambient at 200 °C. Then a layer of OTS was deposited by spin-coating method to improve the surface characteristics of the gate dielectric. Afterwards, P3HT was deposited by spin-coating method. The OTFTs were characterized by I-V measurement and 1/f noise measurement. The OTFT with gate dielectric annealed in NH3 displays higher carrier mobility, smaller threshold voltage, smaller sub-threshold swing, and lower 1/f noise level than the OTFT annealed in N2. Moreover, the HfTiO dielectric film annealed in NH3 shows higher dielectric constant. In summary, HfTiO film annealed in NH 3 at low temperature is a promising candidate to act as the gate dielectric of high-quality low-voltage OTFTs. ©2009 IEEE.published_or_final_versionThe IEEE International Conference of Electron Devices and Solid-State Circuits (EDSSC 2009), Xi'an, China, 25-27 December 2009. In Proceedings of EDSSC, 2009, p. 201-20

A pancake-shaped nano-aggregate for focusing surface plasmons

We proposed a pancake-shaped nano-aggregate that highly focuses surface plasmons. The structure is a superposition of bowtie-shaped dimers, where surface plasmons are excited, resonated with the structure, and coupled. Surface integral equation method (Poggio-Miller-Chang-Harrington-Wu-Tsai method) is used to predict the performance of the proposed structure. It is a method which can accurately calculate the near-fields of nanoparticles. Based on the numerical prediction, the proposed structure shows an electric field (E-field) enhancement of more than 400 times, which is equivalent to a Raman enhancement factor of more than 2.5 e 10 times. It is promising for single molecule detections using surface-enhanced Raman scattering. The physics of the proposed structure are revealed. It is useful to design nanostructures for high E-field enhancement. © 2012 American Institute of Physics.published_or_final_versio

Hierarchical task network approach for time and budget constrained construction project planning

© 2019 The Author(s). Completing a construction project on time and within budget is of great importance in the construction industry. To achieve this goal, a construction plan satisfying the time and cost constraints is crucial. While a rich amount of literature on the time-cost trade-off scheduling and time/cost optimization scheduling has been presented, developing a construction plan for the time and cost-constrained construction project has not been fully explored. This study presented a hierarchical task network (HTN) based construction planning model to fill this gap. First of all, a knowledge formalism catering to the HTN planning was provided to accommodate the construction planning knowledge. Then, the planning process was explained in detail, including temporal reasoning used to sequence the construction activities, and backtracking evasion mechanism used to avoid the trouble of backtracking due to inappropriate selection of execution modes for construction activities. Finally, two sets of comparisons based on a fictional construction project were performed, the results of which demonstrate that the time and budget constraints have an impact on the sec-tion of execution modes for construction methods, and the proposed planning model can develop construction plan that satisfies the specified deadline and budget limitations effectively regardless of the existing of backtracking

Effect of ZnO surface defects on efficiency and stability of ZnO-based perovskite solar cells

ZnO as an alternative electron transport layer (ETL) material for perovskite solar cell applications has drawn increasing research interest due to its comparable energy levels to TiO2, relatively high electron mobility, as well as its feasibility to be processed at low temperatures for potential applications in flexible devices. Nevertheless, ZnO based perovskite devices usually exhibit inferior performance and severe stability drawbacks which are related to the surface defects of ZnO ETL. In this study, to investigate the correlation between ZnO defect composition and resulting device performance, different approaches of preparing ZnO ETL are compared in terms of the perovskite morphology and device performance. In addition, direct manipulations of ZnO surface defects are performed by various surface treatments, and the photovoltaic performance of devices with ZnO ETL subjected to different surface treatments is compared. Surface modification of ZnO ETL by ethanolamine (EA) is demonstrated to efficiently enhance the photovoltaic performance of resulting ZnO based devices. © (2017) COPYRIGHT Societypublished_or_final_versio

Effects of annealing temperature and gas on pentacene OTFTs with HfLaO as gate dielectric

Pentacene organic thin-film transistors (OTFTs) with high-κ HfLaO as gate insulator were fabricated. HfLaO film was prepared by sputtering method. To improve the film quality, the dielectric was annealed in N 2, NH 3, or O 2 at two temperatures, i.e., 200 °C and 400 °C, respectively. The I-V characteristics of the OTFTs and C-V characteristics of corresponding organic capacitors were measured. The OTFTs could operate at a low operating voltage of below 5 V, and the dielectric constant of the HfLaO film could be above ten. For all the annealing gases, the OTFTs annealed at 400 °C achieved higher carrier mobility than their counterparts annealed at 200 °C (with the one annealed in NH 3 at 400 °C showing the highest carrier mobility of 0.45 cm 2/ V·s), which could be supported by SEM images which indicate that pentacene tended to form larger grains on HfLaO annealed at 400 °C than on that annealed at 200 °C. The C-V measurement of the organic capacitors indicated that the localized charge density in the organic semiconductor/oxide was lower for the 400 °C annealing than for the 200 °C annealing. Furthermore, through the characterization of gate current leakage, HfLaO film annealed at 400 °C achieved much smaller leakage than that annealed at 200 °C. Since the maximum processing temperature of ITO glass substrates is around 400 °C , this study shows that 400 °C is suitable for the annealing of HfLaO film in high-performance OTFTs on glass substrate. © 2011 IEEE.published_or_final_versio