Effects of Single Metal-Ion Doping on the Visible-Light Photoreactivity of TiO_2

Titanium dioxide (M-TiO_2), which was doped with 13 different metal ions (i.e., silver (Ag^+), rubidium (Rb^+), nickel (Ni^(2+)), cobalt (Co^(2+)), copper (Cu^(2+)), vanadium (V^(3+)), ruthenium (Ru^(3+)), iron (Fe^(3+)), osmium (Os^(3+)), yttrium (Y^(3+)), lanthanum (La^(3+)), platinum (Pt^(4+), Pt^(2+)), and chromium (Cr3+, Cr6+)) at doping levels ranging from 0.1 to 1.0 at. %, was synthesized by standard sol−gel methods and characterized by X-ray diffraction, BET surface area measurement, SEM, and UV−vis diffuse reflectance spectroscopy. Doping with Pt(IV/II), Cr(III), V(III), and Fe(III) resulted in a lower anatase to rutile phase transformation (A−R phase transformation) temperature for the resultant TiO_2 particles, while doping with Ru(III) inhibited the A−R phase transformation. Metal-ion doping also resulted in a red shift of the photophysical response of TiO_2 that was reflected in an extended absorption in the visible region between 400 and 700 nm. In contrast, doping with Ag(I), Rb(I), Y(III), and La(III) did not result in a red shift of the absorption spectrum of TiO_2. As confirmed by elemental composition analysis by energy dispersive X-ray spectroscopy, the latter group of ions was unable to be substituted for Ti(IV) in the crystalline matrix due to their incompatible ionic radii. The photocatalytic activities of doped TiO_2 samples were quantified in terms of the photobleaching of methylene blue, the oxidation of iodide (I^(−)), and the oxidative degradation of phenol in aqueous solution both under visible-light irradiation (λ > 400 nm) and under broader-band UV−vis irradiation (λ > 320 nm). Pt- and Cr-doped TiO_2, which had relatively high percentages of rutile in the particle phase, showed significantly enhanced visible-light photocatalytic activity for all three reaction classes

Crystal Structure of Human Mre11: Understanding Tumorigenic Mutations

SummaryMre11 plays an important role in repairing damaged DNA by cleaving broken ends and by providing a platform for other DNA repair proteins. Various Mre11 mutations have been identified in several types of cancer. We have determined the crystal structure of the human Mre11 core (hMre11), which contains the nuclease and capping domains. hMre11 dimerizes through the interfaces between loop β3-α3 from one Mre11 and loop β4-β5 from another Mre11, and between loop α2-β3 from one Mre11 and helices α2 and α3 from another Mre11, and assembles into a completely different dimeric architecture compared with bacterial or archaeal Mre11 homologs. Nbs1 binds to the region containing loop α2-β3 which participates in dimerization. The hMre11 structure in conjunction with biochemical analyses reveals that many tumorigenic mutations are primarily associated with Nbs1 binding and partly with nuclease activities, providing a framework for understanding how mutations inactivate Mre11

Career Development for Youth with Disabilities in South Korea: The Intersection of Culture, Theory, and Policy

Youth with disabilities face difficulties resulting from attitudinal, environmental, and organizational barriers not only in initially accessing and entering school (World Health Organization [WHO], 2011), but also as they transition from school age youth to working adults.  With a focus on facilitating a better understanding of the issues, challenges, and solutions associated with the design and implementation of career development services for youth with disabilities, this article describes the status quo for students with disabilities in South Korea and then discusses career development services that potentially reduce variation, help facilitate optimal career development, and promote future employment opportunities.  To accomplish this task, we explore the intersection of culture, theory, and policy in the Korean transition service delivery system

Plan-Draw-Evaluate (PDE) pattern in students' collaborative drawing: Interaction between visual and verbal modes of representation

The use of group drawing to promote student-generated representation is a common instructional strategy as it combines the benefits of using visual representation and collaborative talk. Although the affordances of group drawing have increasingly been emphasized in science education, few studies have investigated how drawing as a visual mode interacts with group discourse as a verbal mode as well as how that interaction facilitates the development of students' collective ideas. Informed by theories in classroom discourse and multimodality, this paper examines the interaction process between a verbal and visual mode of representation as groups of students engaged in collaborative drawing during guided science inquiry lessons. On the basis of the analysis of data from a science class that adopted group drawing, we found and documented a recurring pattern, Plan-Draw-Evaluate or PDE pattern, in how the interaction between the verbal and visual modes occurred during collaborative drawing. This PDE pattern consisted of a triad of moves that alternate between the two modes and fulfilled various discursive purposes, such as suggesting, requesting, recording, visualizing, elaborating, agreeing, and rejecting. The PDE pattern provided a basic social structure that facilitated the collaboration and progression of students' ideas. With illustrations of PDE patterns and its variations, we argue that the PDE pattern provides an insight into the dynamic organization of interactions involved in group drawing that takes into consideration the multimodal affordances of verbal and visual modes of representation and the progression of ideas developed through collaborative discourse

Who Are Less Likely to Receive Subsequent Chemotherapy Beyond First-Line Therapy for Advanced Non-small Cell Lung Cancer?: Implications for Selection of Patients for Maintenance Therapy

BackgroundProspective studies have implied that maintenance therapy for non-small cell lung cancer (NSCLC) has its effect by giving active drugs earlier to patients who otherwise die without receiving second-line therapy. The purpose of this study was to select patients with NSCLC who could most benefit from maintenance therapy, by evaluating which patients would be less likely to receive second-line therapy.MethodsClinicopathologic data of patients with advanced NSCLC who received four cycles of first-line chemotherapy followed by time-off therapy and eventual disease progression or death were reviewed retrospectively. Patients were grouped into ones with first-line therapy only or ones with more than first-line therapy. Clinical characteristics between the two groups were compared.ResultsA total of 271 patients were eligible for analysis, and 39 patients (14.4%) received only first-line therapy. Patients significantly more likely to receive only first-line therapy had performance status of two or three after first-line therapy, large volume of initial target lesions (sum of long diameters ≥70 mm), or smaller decrease in target lesions (decrease <20%) after first-line therapy. Median overall survival of the 143 patients (52.8%) with at least one of these characteristics (16.3 months) was significantly shorter than that of patients without any of these characteristics (23.5 months, p = 0.007).ConclusionMaintenance therapy may be of greater benefit to patients with NSCLC who have clinical characteristics including poor performance status after first-line therapy, large initial target lesions, or smaller decrease in target lesions after first-line therapy

Bioinformatic Analysis of Nematode Migration-Associated Genes Identifies Novel Vertebrate Neural Crest Markers

Neural crest cells are highly motile, yet a limited number of genes governing neural crest migration have been identified by conventional studies. To test the hypothesis that cell migration genes are likely to be conserved over large evolutionary distances and from diverse tissues, we searched for vertebrate homologs of genes important for migration of various cell types in the invertebrate nematode and examined their expression during vertebrate neural crest cell migration. Our systematic analysis utilized a combination of comparative genomic scanning, functional pathway analysis and gene expression profiling to uncover previously unidentified genes expressed by premigratory, emigrating and/or migrating neural crest cells. The results demonstrate that similar gene sets are expressed in migratory cell types across distant animals and different germ layers. Bioinformatics analysis of these factors revealed relationships between these genes within signaling pathways that may be important during neural crest cell migration