Korea University

About: Korea University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Catalysis. The organization has 39756 authors who have published 82424 publications receiving 1860927 citations. The organization is also known as: Bosung College & Bosung Professional College.

Age-Related Differences in Achievement Goal Differentiation.

Abstract: Validity of the 2 X 2 achievement goal framework for school-aged children and adolescents was examined, using self-report responses from 1,196 Korean elementary and middle school students. Confirmatory factor analysis models hypothesizing 4 distinct achievement goal factors demonstrated the best fit in all age groups. Nevertheless, achievement goals of these young students were strongly correlated with each other, regardless of the goal definition or valence. The correlation became increasingly weaker with the increasing age of the respondents. Students in Grades 1-4 endorsed a mastery-approach goal most strongly, but those in Grades 5-9 endorsed a performance-approach goal. Performance-avoidance and mastery-avoidance goals received significantly lower average ratings than did the 2 approach goals in all age groups. Whereas both mastery-approach and performance-approach goals correlated positively with self-efficacy, strategy use, and performance in math, only the performance-approach goal correlated positively with anxiety. Anxiety also correlated positively with the 2 avoidance goals. A performance-avoidance goal further demonstrated positive correlation with help-seeking avoidance, whereas a mastery-avoidance goal did so with strategy use.

Sub-telomere directed gene expression during initiation of invasive aspergillosis.

Abstract: Aspergillus fumigatus is a common mould whose spores are a component of the normal airborne flora. Immune dysfunction permits developmental growth of inhaled spores in the human lung causing aspergillosis, a significant threat to human health in the form of allergic, and life-threatening invasive infections. The success of A. fumigatus as a pathogen is unique among close phylogenetic relatives and is poorly characterised at the molecular level. Recent genome sequencing of several Aspergillus species provides an exceptional opportunity to analyse fungal virulence attributes within a genomic and evolutionary context. To identify genes preferentially expressed during adaptation to the mammalian host niche, we generated multiple gene expression profiles from minute samplings of A. fumigatus germlings during initiation of murine infection. They reveal a highly co-ordinated A. fumigatus gene expression programme, governing metabolic and physiological adaptation, which allows the organism to prosper within the mammalian niche. As functions of phylogenetic conservation and genetic locus, 28% and 30%, respectively, of the A. fumigatus subtelomeric and lineage-specific gene repertoires are induced relative to laboratory culture, and physically clustered genes including loci directing pseurotin, gliotoxin and siderophore biosyntheses are a prominent feature. Locationally biased A. fumigatus gene expression is not prompted by in vitro iron limitation, acid, alkaline, anaerobic or oxidative stress. However, subtelomeric gene expression is favoured following ex vivo neutrophil exposure and in comparative analyses of richly and poorly nourished laboratory cultured germlings. We found remarkable concordance between the A. fumigatus host-adaptation transcriptome and those resulting from in vitro iron depletion, alkaline shift, nitrogen starvation and loss of the methyltransferase LaeA. This first transcriptional snapshot of a fungal genome during initiation of mammalian infection provides the global perspective required to direct much-needed diagnostic and therapeutic strategies and reveals genome organisation and subtelomeric diversity as potential driving forces in the evolution of pathogenicity in the genus Aspergillus.

Two Chloroplast DNA Inversions Originated Simultaneously During the Early Evolution of the Sunflower Family (Asteraceae)

Abstract: The chloroplast DNA (cpDNA) inversion in the Asteraceae has been cited as a classic example of using genomic rearrangements for defining major lineages of plants. We further characterize cpDNA inversions in the Asteraceae using extensive sequence comparisons among 56 species, including representatives of all major clades of the family and related families. We determine the boundaries of the 22-kb (now known as 22.8 kb) inversion that defines a major split within the Asteraceae, and in the process, we characterize the second and a new, smaller 3.3-kb inversion that occurs at one end of the larger inversion. One end point of the smaller inversion is upstream of the trnE-UUC gene, and the other end point is located between the trnC-GCA and rpoB genes. Although a diverse sampling of Asteraceae experienced substantial length variation and base substitution during the long evolutionary history subsequent to the inversion events, the precise locations of the inversion end points are identified using comparative sequence alignments in the inversion regions. The phylogenetic distribution of two inversions is identical among the members of Asteraceae, suggesting that the inversion events likely occurred simultaneously or within a short time period shortly after the origin of the family. Estimates of divergence times based on ndhF and rbcL sequences suggest that two inversions originated during the late Eocene (38-42 MYA). The divergence time estimates also suggest that the Asteraceae originated in the mid Eocene (42-47 MYA).

Morphology Control Enables Efficient Ternary Organic Solar Cells.

Abstract: Ternary organic solar cells are promising alternatives to the binary counterpart due to their potential in achieving high performance. Although a growing number of ternary organic solar cells are recently reported, less effort is devoted to morphology control. Here, ternary organic solar cells are fabricated using a wide-bandgap polymer PBT1-C as the donor, a crystalline fused-ring electron acceptor ITIC-2Cl, and an amorphous fullerene derivative indene-C60 bisadduct (ICBA) as the acceptor. It is found that ICBA can disturb π-π interactions of the crystalline ITIC-2Cl molecules in ternary blends and then help to form more uniform morphology. As a result, incorporation of 20% ICBA in the PBT1-C:ITIC-2Cl blend enables efficient charge dissociation, negligible bimolecular recombination, and balanced charge carrier mobilities. An impressive power conversion efficiency (PCE) of 13.4%, with a high fill factor (FF) of 76.8%, is eventually achieved, which represents one of the highest PCEs reported so far for organic solar cells. The results manifest that the adoption of amorphous fullerene acceptor is an effective approach to optimizing the ternary blend morphology and thereby increases the solar cell performance.