Joint Channel-and-Data Estimation for Large-MIMO Systems with Low-Precision ADCs

The use of low precision (e.g., 1-3 bits) analog-to-digital convenors (ADCs) in very large multiple-input multiple-output (MIMO) systems is a technique to reduce cost and power consumption. In this context, nevertheless, it has been shown that the training duration is required to be {\em very large} just to obtain an acceptable channel state information (CSI) at the receiver. A possible solution to the quantized MIMO systems is joint channel-and-data (JCD) estimation. This paper first develops an analytical framework for studying the quantized MIMO system using JCD estimation. In particular, we use the Bayes-optimal inference for the JCD estimation and realize this estimator utilizing a recent technique based on approximate message passing. Large-system analysis based on the replica method is then adopted to derive the asymptotic performances of the JCD estimator. Results from simulations confirm our theoretical findings and reveal that the JCD estimator can provide a significant gain over conventional pilot-only schemes in the quantized MIMO system.Comment: 7 pages, 4 figure

Exposure of the Hidden Anti-Ferromagnetism in Paramagnetic CdSe:Mn Nanocrystals

We present theoretical and experimental investigations of the magnetism of paramagnetic semiconductor CdSe:Mn nanocrystals and propose an efficient approach to the exposure and analysis of the underlying anti-ferromagnetic interactions between magnetic ions therein. A key advance made here is the build-up of an analysis method with the exploitation of group theory technique that allows us to distinguish the anti-ferromagnetic interactions between aggregative Mn2+ ions from the overall pronounced paramagnetism of magnetic ion doped semiconductor nanocrystals. By using the method, we clearly reveal and identify the signatures of anti-ferromagnetism from the measured temperature dependent magnetisms, and furthermore determine the average number of Mn2+ ions and the fraction of aggregative ones in the measured CdSe:Mn nanocrystals.Comment: 26 pages, 5 figure

A Comparative Study for 2D and 3D Computer-aided Diagnosis Methods for Solitary Pulmonary Nodules

Many computer-aided diagnosis (CAD) methods, including 2D and 3D approaches, have been proposed for solitary pulmonary nodules (SPNs). However, the detection and diagnosis of SPNs remain challenging in many clinical circumstances. One goal of this work is to investigate the relative diagnostic accuracy of 2D and 3D methods. An additional goal is to develop a two-stage approach that combines the simplicity of 2D and the accuracy of 3D methods. The experimental results show statistically significant differences between the diagnostic accuracy of 2D and 3D methods. The results also show that with a very minor drop in diagnostic performance the two-stage approach can significantly reduce the number of nodules needed to be processed by the 3D method, streamlining the computational demand

GPER-induced signaling is essential for the survival of breast cancer stem cells.

G protein-coupled estrogen receptor-1 (GPER), a member of the G protein-coupled receptor (GPCR) superfamily, mediates estrogen-induced proliferation of normal and malignant breast epithelial cells. However, its role in breast cancer stem cells (BCSCs) remains unclear. Here we showed greater expression of GPER in BCSCs than non-BCSCs of three patient-derived xenografts of ER- /PR+ breast cancers. GPER silencing reduced stemness features of BCSCs as reflected by reduced mammosphere forming capacity in vitro, and tumor growth in vivo with decreased BCSC populations. Comparative phosphoproteomics revealed greater GPER-mediated PKA/BAD signaling in BCSCs. Activation of GPER by its ligands, including tamoxifen (TMX), induced phosphorylation of PKA and BAD-Ser118 to sustain BCSC characteristics. Transfection with a dominant-negative mutant BAD (Ser118Ala) led to reduced cell survival. Taken together, GPER and its downstream signaling play a key role in maintaining the stemness of BCSCs, suggesting that GPER is a potential therapeutic target for eradicating BCSCs

A naturally occurring carotenoid, lutein, reduces PDGF and H2O2 signaling and compromised migration in cultured vascular smooth muscle cells

<p>Abstract</p> <p>Background</p> <p>Platelet-derived growth factor (PDGF) is a potent stimulator of growth and motility of vascular smooth muscle cells (VSMCs). Abnormalities of PDGF/PDGF receptor (PDGFR) are thought to contribute to vascular diseases and malignancy. We previously showed that a carotenoid, lycopene, can directly bind to PDGF and affect its related functions in VSMCs. In this study we examined the effect of the other naturally occurring carotenoid, lutein, on PDGF signaling and migration in VSMCs.</p> <p>Methods</p> <p>Western blotting was performed to examine PDGF and H₂O₂signaling. Flowcytometry was used to determine PDGF binding to VSMCs. Fluorescence microscopy was performed to examine intracellular ROS production. Modified Boyden chamber system (Transwell apparatus) was used for migration assay.</p> <p>Results</p> <p>Lutein reduced PDGF signaling, including phosphorylation of PDGFR-β and its downstream protein kinases/enzymes such as phospholipase C-γ, Akt, and mitogen-activated protein kinases (MAPKs). Although lutein possesses a similar structure to lycopene, it was striking that lutein inhibited PDGF signaling through a different way from lycopene in VSMCs. Unlike lycopene, lutein not only interacted with (bound to) PDGF but also interfered with cellular components. This was evidenced that preincubation of PDGF with lutein and treatment of VSMCs with lutein followed by removing of lutein compromised PDGF-induced signaling. Lutein reduced PDGF-induced intracellular reactive oxygen species (ROS) production and attenuated ROS- (H₂O₂-) induced ERK1/2 and p38 MAPK activation. A further analysis indicated lutein could inhibit a higher concentration of H₂O₂-induced PDGFR signaling, which is known to act through an oxidative inhibition of protein tyrosine phosphatase. Finally, we showed that lutein functionally inhibited PDGF-induced VSMC migration, whereas its stereo-isomer zeaxanthin did not, revealing a special action of lutein on VSMCs.</p> <p>Conclusions</p> <p>Our study reveals a differential action mechanism of lutein from other reported caroteinoids and suggests a possible beneficial effect of lutein but not zeaxanthin on prevention of vascular diseases.</p

WHAT DETERMINATES STUDENT LEARNING SATISFACTION IN A BLENDED E-LEARNING SYSTEM ENVIRONMENT?

This paper presents a learning satisfaction model that examines the determinant factors for student learning satisfaction in a blended e-learning environment. Conformation factor analysis was performed to test the reliability and validity of the measurement model. The partial least squares method was used to evaluate the causal model. The results indicated that the learning climate, perceived value and perceived ease of use significantly affected learning satisfaction. Computer self-efficacy had a strong impact on perceived behavioral control; computer self-efficacy, perceived behavioral control and social interaction had significant effects on perceived ease of use. System functionality, content feature and social interaction significantly affected perceived value. Social interaction had a significant effect on learning climate. This paper provides initial insights into those factors that are likely significant antecedents for planning and implementing a blended e-learning system to enhance student learning satisfaction

A CMMI-based approach for medical software project life cycle study

In terms of medical techniques, Taiwan has gained international recognition in recent years. However, the medical information system industry in Taiwan is still at a developing stage compared with the software industries in other nations. In addition, systematic development processes are indispensable elements of software development. They can help developers increase their productivity and efficiency and also avoid unnecessary risks arising during the development process. Thus, this paper presents an application of Light-Weight Capability Maturity Model Integration (LW-CMMI) to Chang Gung Medical Research Project (CMRP) in the Nuclear medicine field. This application was intended to integrate user requirements, system design and testing of software development processes into three layers (Domain, Concept and Instance) model. Then, expressing in structural System Modeling Language (SysML) diagrams and converts part of the manual effort necessary for project management maintenance into computational effort, for example: (semi-) automatic delivery of traceability management. In this application, it supports establishing artifacts of “requirement specification document”, “project execution plan document”, “system design document” and “system test document”, and can deliver a prototype of lightweight project management tool on the Nuclear Medicine software project. The results of this application can be a reference for other medical institutions in developing medical information systems and support of project management to achieve the aim of patient safety. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2193-1801-2-266) contains supplementary material, which is available to authorized users

The Study on Antecedents of Consumer Buying Impulsiveness in an Online Context

The global recession caused by the financial tsunami has seriously impacted numerous industries. Although the market scale of global e-commerce market has declined, global online shopping continues to grow. Many previous researches focused on the effect of website design characteristics on online impulsive buying behavior, and few have explored such behavior from consumer individual internal factor perspectives. This paper aims to explore and integrate individual internal factors influencing consumer online buying impulsiveness, and further to recognize the relationships among these factors. The results showed as follows: (1) hedonic consumption needs, impulsive buying tendency, positive affect and normative evaluations positively influence buying impulsiveness, respectively; (2) hedonic consumption needs positively influence positive affect; (3) impulsive buying tendency positively influences normative evaluations; (4) normative evaluations positively influence positive affect