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"Wu, S. W."
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Atomic-Scale Coupling of Photons to Single-Molecule Junctions
Spatial resolution at the atomic scale has been achieved in the coupling of light to single molecules adsorbed on a surface. Electron transfer to a single molecule induced by green to near-infrared light in the junction of a scanning tunneling microscope (STM) exhibited spatially varying probability that is confined within the molecule. The mechanism involves photo-induced resonant tunneling in which a photoexcited electron in the STM tip is transferred to the molecule. The coupling of photons to the tunneling process provides a pathway to explore molecular dynamics with the combined capabilities of lasers and the STM.
Journal Article
A novel slug-containing negative-feedback loop regulates SCF/c-Kit-mediated hematopoietic stem cell self-renewal
The stem cell factor (SCF)/c-Kit pathway has crucial roles in controlling hematopoietic stem cell (HSC) renewal. However, little is known about the intracellular regulation of the SCF/c-Kit pathway in HSCs. We report here that Slug, a zinc-finger transcription repressor, functions as a direct transcriptional repressor of
c-Kit
in HSCs. Conversely, SCF/c-Kit signaling positively regulates Slug through downstream c-Myc and FoxM1 transcription factors. Intriguingly,
c-Kit
expression is induced by SCF/c-Kit signaling in Slug-deficient HSCs. The balance between Slug and c-Kit is critical for maintaining HSC repopulating potential
in vivo
. Together, our studies demonstrate that Slug functions in a novel negative-feedback regulatory loop in the SCF/c-Kit signaling pathway in HSCs.
Journal Article
Tunneling Rates in Electron Transport through Double-Barrier Molecular Junctions in a Scanning Tunneling Microscope
The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends.
Journal Article
Knowledge management implementation in the school context: case studies on knowledge leadership, storytelling, and taxonomy
Teachers and school administrators in Hong Kong have had to cope with more work and performance pressure as they strive to implement educational reforms aimed at deepening students’ life-long learning skills. Management systems, which save time and transfer ideas, experiences, and knowledge more efficiently could help schools meet reform goals and relieve the occupational stress that inevitably accompanies change and progress. This paper explores the effect of knowledge management (KM) for school development by reviewing three cases selected from a school improvement project entitled “Knowledge Management and Primary School Development”. The project was launched specifically to determine if KM practices can assist educators to cope with added pressures and rise to the challenges of education reforms. The case studies illustrate three separate approaches to incorporating KM systems. Problems faced by these case-schools included declining school competitiveness, time-consuming data storage and retrieval practices, and hierarchical communication structures that stunted feedback from the teachers who are on the front line of educational reform. Interviews were conducted with school principals, middle managers, and teachers. The results show that the core KM strategies of personalization and codification can be adopted to improve school development. Knowledge leadership, knowledge sharing culture, and knowledge management system support were identified as success factors for schools to implement KM.
Journal Article
Identification of quantitative trait locus and positional candidate loci influencing chicken egg quality under tropical conditions
Egg quality is a vital factor in the poultry industry. High-quality eggs not only meet consumer expectations for appearance, taste, and nutritional value but also have high marketability, profitability, and consumer satisfaction. Accordingly, we executed our research with the purpose of determining chromosomal regions and genetic markers associated with egg quality in an F2 cross-bred chicken population under tropical conditions; we determined these through a genome-wide association study and quantitative trait locus (QTL) mapping. This population was created by cross-breeding the L2 line of Taiwan Country chickens, which is adapted to local conditions in Taiwan, with an experimental line (R-line) of Rhode Island Red layer chickens, which was developed by the French National Research Institute for Agriculture, Food and the Environment. A 60 K single nucleotide polymorphism (SNP) genotyping array for chickens was employed to execute the analysis. Our analysis revealed 40 QTLs associated with egg quality under tropical conditions, namely 20 QTLs with genome-wide statistical significance and 20 QTLs with chromosome-wide statistical significance. Furthermore, we identified 93 SNPs exerting discernible effects on egg quality, with 10 of these effects exhibiting genome-wide significance and 83 exhibiting potential significance. The majority of the detected QTL regions and SNPs agreed with those identified as having an association with egg quality or production traits in previous studies, thus supporting the interrelationships determined between the studied characteristics. The findings of this study enhance the understanding regarding the genetic regulation governing chicken egg quality, thereby serving as a valuable reference for future functional investigations.
Journal Article
Monopolar square patch antennas with wideband operation
The design of a wideband patch antenna with monopole-like conical radiation patterns is presented. The antenna has a square patch that is shorted to the ground plane through two shorting walls and is excited by a top-loaded coaxial feed centred below the square patch. Several prototypes with various antenna heights are implemented and measured. A prototype with impedance bandwidth of about 50% is achieved when its height is less than 0.09 free-space wavelengths.
Journal Article
Broadband circularly-polarised slot antenna array
A stacked slot antenna is proposed and studied to improve the performance of a circularly-polarised (CP) annular-ring slot antenna that has the disadvantages of a narrow bandwidth, a lower gain and bidirectional radiation. The stacked antenna structure is composed of a circular wide slot, a parasitic patch and a metallic reflector, and its CP radiation is excited through the proximity coupling of an L-shaped microstrip line. A 4X4 array using the stacked slot antenna as an element is also developed and designed at X-band. Details of the antenna design and obtained results are presented.
Journal Article
Adsorption of Eu(III) on oMWCNTs: Effects of pH, Ionic Strength, Solid-Liquid Ratio and Water-Soluble Fullerene
The influences of pH, ionic strength, solid-liquid ratio, C60CCOOH2n, and C60(OH)n on Eu(III) adsorption onto the oxidation multiwalled carbon nanotubes (oMWCNTs) were studied by using batch technique. The dynamic process showed that the adsorption of Eu(III) onto oMWCNTs could be in equilibrium for about 17 h and matched the quasi-second-order kinetics model. The sorption process was influenced strongly by pH changes and ionic strength. In the pH range of 1.0 to 4.0, the adsorption ratio increased with the increasing of pH values, then the adsorption of Eu(III) was almost saturated in the pH range of 4.0 to 10.0, and the adsorption ratio reached about 90%. The adsorption ratio decreased with the increasing of ionic strength. C60CCOOH22 could promote the adsorption process obviously, but C60(OH)n competed with Eu(III) for the adsorption sites, thus leading to the reducing of Eu(III) adsorption onto oMWCNTs. In the presence of C60CCOOH2n or C60(OH)n, the adsorption of Eu(III) onto oMWCNTs could be affected obviously by solid-liquid ratio and the initial concentration of Eu(III).
Journal Article
Work addiction in Chinese white-collar workers: the psychometric properties of its measure and its comorbidity with general anxiety in network analysis
Background
Work addiction (WA) threatens occupation-related health in many countries including China. This research aims to evaluate the psychometric properties of the Chinese version of Bergen Work Addiction Scale (BWAS), the most common measure of WA, to facilitate relevant studies in Chinese workers. A network analysis was further conducted to identify central and bridge symptoms within the WA-anxiety network to improve intervention practices.
Methods
A total of 694 Chinese white-collar workers completed an online questionnaire survey in March of 2022, and the responses to BWAS from a subsample of 50 participants one month after this survey were also collected.
Results
The unidimensionality of BWAS was supported by results of exploratory factor analysis, exploratory graph analysis, and confirmatory factor analysis and we found satisfactory internal consistency and acceptable test-retest reliability. Multiple-group factor analyses confirmed the measurement invariance of BWAS across genders, districts (i.e., central China, eastern China, western China, and northeastern China), and age groups (i.e., young and middle-aged adults) while the convergent validity of BWAS was demonstrated by its significant correlations with Dutch Work Addiction Scale (
r =
0.62,
p <
0.001) and its criterion validity was indicated by its significant correlations with general anxiety, weekly work hours, and health status (
r =
-0.16 to 0.31,
p <
0.001–0.01). Network analysis further revealed two central symptoms (WA-tolerance and WA-problems) and three bridge symptoms (WA-problems, WA-mood modification, and mouth dryness of general anxiety) maintaining the WA-anxiety comorbidity.
Conclusions
Our findings suggest that BWAS is a valid measure of WA in Chinese workers and interventions should put special attention to the identified central and bridge symptoms underlying the WA-anxiety network.
Journal Article