403 research outputs found
Supply Voltage and Temperature Insensitive Current Reference for the 4 MHz Oscillator
[[abstract]]This paper presents a 4 MHz current control ring oscillator with a new temperature and supply voltage immune current reference implemented by 0.35um CMOS technology. Compared to the conventional oscillator with current reference techniques, the proposed approach shows a significant improvement for the sensitivities of temperature and supply voltage. The current reference is designed by combining positive and negative temperature effect circuits, such that it can exempt from the temperature and supply voltage variations. By HSPICE simulation, this new current reference is insensitive to the supply voltage with variations of -0.47%~0.67% over the supply voltage range of 2.97V to 3.63V, and it is also insensitive to the temperature with variation of 366 ppm/C over the temperature range of -40C to 100C. The proposed oscillator frequency is insensitive to the supply voltage with variations of -15%~20% over the supply voltage range of 2.97V to 3.63V, and it is insensitive to temperature with variation of 404 ppm/C over the temperature range of -40C to 100C.[[abstract]]This paper presents a 4 MHz current control ring oscillator with a new temperature and supply voltage immune current reference implemented by 0.35nm CMOS technology. Compared to the conventional oscillator with current reference techniques, the proposed approach shows a significant improvement for the sensitivities of temperature and supply voltage. The current reference is designed by combining positive and negative temperature effect circuits, such that it can exempt from the temperature and supply voltage variations. By HSPICE simulation, this new current reference is insensitive to the supply voltage with variations of -0.47%~0.67% over the supply voltage range of 2.97V to 3.63V, and it is also insensitive to the temperature with variation of 366 ppm/°C over the temperature range of -40°C to 100°C. The proposed oscillator frequency is insensitive to the supply voltage with variations of -15%~20% over the supply voltage range of 2.97V to 3.63V, and it is insensitive to temperature with variation of 404 ppm/°C over the temperature range of-40°C to 100°C.[[conferencetype]]國際[[conferencedate]]20111212~2011121
A Bayesian measurement error model for two-channel cell-based RNAi data with replicates
RNA interference (RNAi) is an endogenous cellular process in which small
double-stranded RNAs lead to the destruction of mRNAs with complementary
nucleoside sequence. With the production of RNAi libraries, large-scale RNAi
screening in human cells can be conducted to identify unknown genes involved in
a biological pathway. One challenge researchers face is how to deal with the
multiple testing issue and the related false positive rate (FDR) and false
negative rate (FNR). This paper proposes a Bayesian hierarchical measurement
error model for the analysis of data from a two-channel RNAi high-throughput
experiment with replicates, in which both the activity of a particular
biological pathway and cell viability are monitored and the goal is to identify
short hair-pin RNAs (shRNAs) that affect the pathway activity without affecting
cell activity. Simulation studies demonstrate the flexibility and robustness of
the Bayesian method and the benefits of having replicates in the experiment.
This method is illustrated through analyzing the data from a RNAi
high-throughput screening that searches for cellular factors affecting HCV
replication without affecting cell viability; comparisons of the results from
this HCV study and some of those reported in the literature are included.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS496 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Single-nucleotide polymorphism-based genetic risk score and patient age at prostate cancer diagnosis
Importance: Few studies have evaluated the association between a single-nucleotide polymorphism-based genetic risk score (GRS) and patient age at prostate cancer (PCa) diagnosis.
Objectives: To test the association between a GRS and patient age at PCa diagnosis and to compare the performance of a GRS with that of family history (FH) in PCa risk stratification.
Design, Setting, and Participants: A cohort study of 3225 white men was conducted as a secondary analysis of the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) chemoprevention trial, a 4-year, randomized, double-blind, placebo-controlled multicenter study conducted from March 2003 to April 2009 to evaluate the safety and efficacy of dutasteride in reducing PCa events. Participants were confirmed to be cancer free by prostate biopsy (6-12 cores) within 6 months prior to the study and underwent 10 core biopsies every 2 years per protocol. The dates for performing data analysis were from July 2016 to October 2019.
Interventions: A well-established, population-standardized GRS was calculated for each participant based on 110 known PCa risk-associated single-nucleotide polymorphisms, which is a relative risk compared with the general population. Men were classified into 3 GRS risk groups based on predetermined cutoff values: low (\u3c0.50), average (0.50-1.49), and high (≥1.50).
Main Outcomes and Measures: Prostate cancer diagnosis-free survival among men of different risk groups.
Results: Among 3225 men (median age, 63 years [interquartile range, 58-67 years]) in the study, 683 (21%) were classified as low risk, 1937 (60%) as average risk, and 605 (19%) as high risk based on GRS alone. In comparison, 2789 (86%) were classified as low or average risk and 436 (14%) as high risk based on FH alone. Men in higher GRS risk groups had a PCa diagnosis-free survival rate that was worse than that of those in the lower GRS risk group (χ2 = 53.3; P \u3c .001 for trend) and in participants with a negative FH of PCa (χ2 = 45.5; P \u3c .001 for trend). Combining GRS and FH further stratified overall genetic risk, indicating that 957 men (30%) were at high genetic risk (either high GRS or positive FH), 1667 men (52%) were at average genetic risk (average GRS and negative FH), and 601 men (19%) were at low genetic risk (low GRS and negative FH). The median PCa diagnosis-free survival was 74 years (95% CI, 73-75 years) for men at high genetic risk, 77 years (95% CI, 75 to \u3e80 years) for men at average genetic risk, and more than 80 years (95% CI, \u3e80 to \u3e80 years) for men at low genetic risk. In contrast, the median PCa diagnosis-free survival was 73 years (95% CI, 71-76 years) for men with a positive FH and 77 years (95% CI, 76-79 years) for men with a negative FH.
Conclusions and Relevance: This study suggests that a GRS is significantly associated with patient age at PCa diagnosis. Combining FH and GRS may better stratify inherited risk than FH alone for developing personalized PCa screening strategies
High efficiency silicon nanodisk laser based on colloidal CdSe/ZnS QDs
Using colloidal CdSe/ZnS quantum dots in the submicron-sized silicon disk cavity, we have developed a visible wavelength nanodisk laser that operates under extremely low threshold power at room temperature. Time-resolved photoluminescence (PL) of QDs; nanodisk by e-beam lithography. Observation of lasing action at 594 nm wavelength for quantum dots on a nanodisk (750 nm in diameter) cavity and an ultra-low threshold of 2.8 µW. From QD concentration dependence studies we achieved nearly sevenfold increase in spontaneous emission (SE) rate. We have achieved high efficient and high SE coupling rate in such a QD nanodisk laser
POINeT: protein interactome with sub-network analysis and hub prioritization
<p>Abstract</p> <p>Background</p> <p>Protein-protein interactions (PPIs) are critical to every aspect of biological processes. Expansion of all PPIs from a set of given queries often results in a complex PPI network lacking spatiotemporal consideration. Moreover, the reliability of available PPI resources, which consist of low- and high-throughput data, for network construction remains a significant challenge. Even though a number of software tools are available to facilitate PPI network analysis, an integrated tool is crucial to alleviate the burden on querying across multiple web servers and software tools.</p> <p>Results</p> <p>We have constructed an integrated web service, POINeT, to simplify the process of PPI searching, analysis, and visualization. POINeT merges PPI and tissue-specific expression data from multiple resources. The tissue-specific PPIs and the numbers of research papers supporting the PPIs can be filtered with user-adjustable threshold values and are dynamically updated in the viewer. The network constructed in POINeT can be readily analyzed with, for example, the built-in centrality calculation module and an integrated network viewer. Nodes in global networks can also be ranked and filtered using various network analysis formulas, i.e., centralities. To prioritize the sub-network, we developed a ranking filtered method (S3) to uncover potential novel mediators in the midbody network. Several examples are provided to illustrate the functionality of POINeT. The network constructed from four schizophrenia risk markers suggests that EXOC4 might be a novel marker for this disease. Finally, a liver-specific PPI network has been filtered with adult and fetal liver expression profiles.</p> <p>Conclusion</p> <p>The functionalities provided by POINeT are highly improved compared to previous version of POINT. POINeT enables the identification and ranking of potential novel genes involved in a sub-network. Combining with tissue-specific gene expression profiles, PPIs specific to selected tissues can be revealed. The straightforward interface of POINeT makes PPI search and analysis just a few clicks away. The modular design permits further functional enhancement without hampering the simplicity. POINeT is available at <url>http://poinet.bioinformatics.tw/</url>.</p
Development of a Game-Based e-Learning System with Augmented Reality for Improving Students’ Learning Performance
Currently, the school children usually spend a lot of time on the games in their recreational activities and some of them are even addicted to the games. Compared with other extracurricular activities, the e-Learning system reflects the fact that school children are very interested in the games. As a result, educators have lately craved to develop effective teaching activities that allow the school children to learn some subjects and to play the games simultaneously. Therefore, this study is based on an e-Learning system which combines the serious game by Unity3D Game Engine with augmented reality (AR). Students are able to acquire their knowledge and to foster logical skills via this game-based e-Learning system. According to its efficacy and utilities, this study has assessed and compared the game-based e-Learning system with the traditional learning and other e-Learning systems. The experimental results have indicated that the proposed game-based e-Learning system can outperform other existing systems
A novel randomly textured phosphor structure for highly efficient white light-emitting diodes
We have successfully demonstrated the enhanced luminous flux and lumen efficiency in white light-emitting diodes by the randomly textured phosphor structure. The textured phosphor structure was fabricated by a simple imprinting technique, which does not need an expensive dry-etching machine or a complex patterned definition. The textured phosphor structure increases luminous flux by 5.4% and 2.5% at a driving current of 120 mA, compared with the flat phosphor and half-spherical lens structures, respectively. The increment was due to the scattering of textured surface and also the phosphor particles, leading to the enhancement of utilization efficiency of blue light. Furthermore, the textured phosphor structure has a larger view angle at the full width at half maximum (87°) than the reference LEDs
Nobiletin Prevents Trimethylamine Oxide-Induced Vascular Inflammation via Inhibition of the NF-κB/MAPK Pathways.
peer reviewedDietary choline and its containing foods are biotransformed to trimethylamine (TMA) via gut microbial metabolism. Subsequently, as an intermediate molecule, TMA is quickly transported and oxidized in the liver by hepatic flavin monooxygenases to form trimethylamine oxide (TMAO). TMAO was treated as a waste byproduct from choline metabolism, but recent convincing evidence demonstrated the association between the small molecule TMAO and inflammation-related diseases, including blood vessel inflammation and vascular diseases. The scope of this study is to investigate the preventive effect of nobiletin on TMAO-induced blood vessel inflammation. Our results from Western blot showed that the inhibition of TMAO-induced cardiovascular inflammation was correlated with nobiletin-mediated inhibitory effects on NF-κB and MAPK/ERK related pathways. More specifically, nobiletin prevented the oxidative damage of vascular sites (proximal aorta), inhibited the activity of MAPK/ERK, reduced the expression of NF-κB p65 and phospho-NF-κB p65, and consequently decreased the inflammatory response. Flow cytometry analyses showed that nobiletin decreased TMAO-induced apoptosis of HUVEC cells and counteracted TMAO-induced HUVEC cell proliferation. Results from HE staining and immunohistochemical results also showed that nobiletin reduced the degree of inflammation of the proximal aorta in Sprague-Dawley rats. In summary, nobiletin significantly reduced TMAO-induced vascular inflammation via inhibition of the NF-κB/MAPK pathways
Diversity of traveling wave solutions in FitzHugh–Nagumo type equations
99學年度楊定揮教師升等參考著作[[abstract]]In this work we consider the diversity of traveling wave solutions of the FitzHugh–Nagumo type equations ut=uxx+ƒ(u, w), Wt=εg(u, w), where f(u,w)=u(u−a(w))(1−u) for some smooth function a(w) and g(u,w)=u−w. When a(w) crosses zero and one, the corresponding profile equation possesses special turning points which result in very rich dynamics. In [W. Liu, E. Van Vleck, Turning points and traveling waves in FitzHugh–Nagumo type equations, J. Differential Equations 225 (2006) 381–410], Liu and Van Vleck examined traveling waves whose slow orbits lie only on two portions of the slow manifold, and obtained the existence results by using the geometric singular perturbation theory. Based on the ideas of their work, we study the co-existence of different traveling waves whose slow orbits could involve all portions of the slow manifold. There are more complicated and richer dynamics of traveling waves than those of [W. Liu, E. Van Vleck, Turning points and traveling waves in FitzHugh–Nagumo type equations, J. Differential Equations 225 (2006) 381–410]. We give a complete classification of all different fronts of traveling waves, and provide an example to support our theoretical analysis.[[incitationindex]]SC
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