National Cheng Kung University

About: National Cheng Kung University is a education organization based out in Tainan City, Taiwan. It is known for research contribution in the topics: Population & Thin film. The organization has 49723 authors who have published 69799 publications receiving 1437420 citations. The organization is also known as: NCKU.

Electrokinetic mixing in microfluidic systems

Abstract: The applications of electrokinetics in the development of microfluidic devices have been widely attractive in the past decade. Electrokinetic devices generally require no external mechanical moving parts and can be made portable by replacing the power supply by small battery. Therefore, electrokinetic-based microfluidic systems can serve as a viable tool in creating a lab-on-a-chip (LOC) or micro-total analysis system (μTAS) for use in biological and chemical assays. Mixing of analytes and reagents is a critical step in realizing lab-on-a-chip. This step is difficult due to the low Reynolds numbers flows in microscale devices. Hence, various schemes to enhance micro-mixing have been proposed in the past years. This review reports recent developments in the micro-mixing schemes based on DC and AC electrokinetics, including electrowetting-on-dielectric (EWOD), dielectrophoresis (DEP), and electroosmosis (EO). These electrokinetic-based mixing approaches are generally categorized as either active or passive in nature. Active mixers either use time-dependent (AC or DC field switching) or time-independent (DC field) external electric fields to achieve mixing, while passive mixers achieve mixing in DC fields simply by virtue of their geometric topology and surface properties, or electrokinetic instability flows. Typically, chaotic mixing can be achieved in some ways and is helpful to mixing under large Peclet number regimes. The overview given in this article provides a potential user or researcher of electrokinetic-based technology to select the most favorable mixing scheme for applications in the field of micro-total analysis systems.

GaN Metalens for Pixel-Level Full-Color Routing at Visible Light

Abstract: Metasurface-based components are known to be one of the promising candidates for developing flat optical systems. However, their low working efficiency highly limits the use of such flat components for feasible applications. Although the introduction of the metallic mirror has been demonstrated to successfully enhance the efficiency, it is still somehow limited for imaging and sensing applications because they are only available for devices operating in a reflection fashion. Here, we demonstrate three individual GaN-based metalenses working in a transmission window with extremely high operation efficiency at visible light (87%, 91.6%, and 50.6% for blue, green, and red light, respectively). For the proof of concept, a multiplex color router with dielectric metalens, which is capable of guiding individual primary colors into different spatial positions, is experimentally verified based on the design of out-of-plane focusing metalens. Our approach with low-cost, semiconductor fabrication compatibility and h...

Dysregulated gene expression networks in human acute myelogenous leukemia stem cells

Abstract: We performed the first genome-wide expression analysis directly comparing the expression profile of highly enriched normal human hematopoietic stem cells (HSC) and leukemic stem cells (LSC) from patients with acute myeloid leukemia (AML). Comparing the expression signature of normal HSC to that of LSC, we identified 3,005 differentially expressed genes. Using 2 independent analyses, we identified multiple pathways that are aberrantly regulated in leukemic stem cells compared with normal HSC. Several pathways, including Wnt signaling, MAP Kinase signaling, and Adherens Junction, are well known for their role in cancer development and stem cell biology. Other pathways have not been previously implicated in the regulation of cancer stem cell functions, including Ribosome and T Cell Receptor Signaling pathway. This study demonstrates that combining global gene expression analysis with detailed annotated pathway resources applied to highly enriched normal and malignant stem cell populations, can yield an understanding of the critical pathways regulating cancer stem cells.

The Relationship among Ethical Climate Types, Facets of Job Satisfaction, and the Three Components of Organizational Commitment : A Study of Nurses in Taiwan

Abstract: The high turnover of nurses has become a global problem. Several studies have proposed that nurses’ perceptions of the ethical climate of their organization are related to higher job satisfaction and organizational commitment, and thus lead to lower turnover. However, there is limited empirical evidence supporting a relationship between different types of ethical climate within organizations and facets of job satisfaction. Furthermore, no published studies have investigated the impact of different types of ethical climate on the three components of organizational commitment. This study attempts to explore the different types of ethical climate that exist in hospitals, and the degree of job satisfaction and organizational commitment of nurses in Taiwan. It uses path analysis to understand which types of ethical climate influence different facets of job satisfaction. The study also examines the impact of different types of ethical climate and facets of job satisfaction on the three components of organizational commitment. Questionnaires were distributed to 352 nurses. The relationships among variables were assessed by factor analysis, reliability, descriptive statistics, correlations, and regression. The important conclusion is that hospitals can increase job satisfaction and organizational commitment by influencing an organization’s ethical climate. Hospital administrators can foster within organizations the climate types of caring, independent, and rules climate that increase satisfaction, while preventing organizations from developing the type of instrumental climate that decreases it.