In this study, we synthesized and characterized multiple resonance (MR) type blue thermally activated delayed fluorescence (TADF) emitters. Unlike many boron-based MR-TADF materials, the blue TADF emitters of this work had an asymmetric molecular structure with one boron, one oxygen, and one nitrogen. The aromatic units linked to the nitrogen were changed into diphenylamine, carbazole, dimethylacridine, and diphenylacridine to manage the light emission properties of the emitters. The TADF emitters exhibited a blue emission due to the weak electron-donating oxygen atom and the emission color was controlled by the aromatic unit connected to the nitrogen. The simple diphenylamine unit was effective in achieving real deepblue emission for the BT2020 standard with a high external quantum efficiency (EQE), while the electron-rich nitrogen-based dimethylacridine and diphenylacridine accelerated the reverse intersystem crossing for high EQE and small EQE roll-off. Among the emitters, a diphenylamine-substituted emitter, 7-(tert-butyl)-9-phenyl-9H-5-oxa-9-aza-13b-boranaphtho-[3,2,1-de]anthracene (B-O-dpa), showed a maximum external quantum efficiency of 16.3%, a small full width at half-maximum of 32 nm, and a real deep-blue color coordinate of (0.15, 0.05).

Visually significant corneal injuries and subsequent scarring collectively represent a major global human health challenge, affecting millions of people worldwide. Unfortunately, less than 2% of patients who could benefit from a sight-restoring corneal transplant have access to cadaveric donor corneal tissue. Thus, there is a critical need for new ways to repair corneal defects that drive proper epithelialization and stromal remodeling of the wounded area without the need for cadeveric donor corneas. Emerging therapies to replace the need for donor corneas include pre-formed biosynthetic buttons and in situ-forming matrices that strive to achieve the transparency, biocompatibility, patient comfort, and biointegration that is possible with native tissue. Herein, we report on the development of an in situ-forming hydrogel of collagen type I crosslinked via multi-functional polyethylene glycol (PEG)-N-hydroxysuccinimide (NHS) and characterize its biophysical properties and regenerative capacity both in vitro and in vivo. The hydrogels form under ambient conditions within minutes upon mixing without the need for an external catalyst or trigger such as light or heat, and their transparency, degradability, and stiffness are modulated as a function of number of PEG arms and concentration of PEG. In addition, in situ-forming PEG-collagen hydrogels support the migration and proliferation of corneal epithelial and stromal cells on their surface. In vivo studies in which the hydrogels were formed in situ over stromal keratectomy wounds without sutures showed that they supported multi-layered surface epithelialization. Overall, the in situ forming PEG-collagen hydrogels exhibited physical and biological properties desirable for a corneal stromal defect wound repair matrix that could be applied without the need for sutures or an external trigger such as a catalyst or light energy.

The extensive design effort for KSTAR has been focused on two major aspects of the KSTAR project mission - steady-state-operation capability and advanced tokamak physics. The steady state aspect of the mission is reflected in the choice of superconducting magnets, provision of actively cooled in-vessel components, and long pulse current drive and heating systems. The advanced tokamak aspect of the mission is incorporated in the design features associated with flexible plasma shaping, double null divertor and passive stabilizers, internal control coils and a comprehensive set of diagnostics. Substantial progress in engineering has been made on superconducting magnets, the vacuum vessel, plasma facing components and power supplies. The new KSTAR experimental facility with cryogenic system and deionized water cooling and main power systems has been designed, and the construction work is under way for completion in 2004.

The Korea Superconducting Tokamak Advanced Research (KSTAR) project is the major effort of the national fusion programme of the Republic of Korea. Its aim is to develop a steady state capable advanced superconducting tokamak to establish a scientific and technological basis for an attractive fusion reactor. The major parameters of the tokamak are: major radius 1.8 m, minor radius 0.5 m, toroidal field 3.5 T and plasma current 2 MA, with a strongly shaped plasma cross-section and double null divertor. The initial pulse length provided by the poloidal magnet system is 20 s, but the pulse length can be increased to 300 s through non-inductive current drive. The plasma heating and current drive system consists of neutral beams, ion cyclotron waves, lower hybrid waves and electron cyclotron waves for flexible profile control in advanced tokamak operating modes. A comprehensive set of diagnostics is planned for plasma control, performance evaluation and physics understanding. The project has completed its conceptual design and moved to the engineering design and construction phase. The target date for the first plasma is 2002.

Bone morphogenetic protein (BMP) 7 counteracts physiological epithelial-to-mesenchymal transition, a process that is indicative of epithelial plasticity in developmental stages. Because epithelial-to-mesenchymal transition and its reversed process mesenchymal-to-epithelial transition (MET) are also involved in cancer progression, we investigated whether BMP7 plays a role in WM-266-4 melanoma cell growth and metastasis. An MTT assay was conducted in WM-266-4 and HEK293T cell lines to show the cell growth inhibition ability of BMP7 and cisplatin. Semiquantitative RT-PCR was used to determine MET in morphologically changed BMP7-treated melanoma cells. MET-induced cells expressed less a basic helix-loop-helix transcription factor (TWIST) in western blot analysis, and we confirm that BMP receptor (Alk2) siRNA transduction could restore TWIST protein expression via blocking of Smad 1, 5 and 8 signaling. Matrigel invasion and cell migration assays were done to investigate the BMP7-induced metastasis inhibition ability. BMP7 treatment only slightly reduced cell growth rate, but induced apparent MET. BMP7 also reduced the invasion and migration ability. Furthermore, BMP7 reduced the resistance of WM-266-4 cells to cisplatin. Collectively, our findings indicate that the metastatis inhibition ability of BMP7 is involved in MET, and that BMP7 could be used as a potential metastasis inhibitor in human melanoma cells. (Cancer Sci 2009; 100: 2218-2225 A lthough 90% of cancer deaths are caused by metastasis, (1) most chemotherapeutic agents cannot prevent tumor metastasis. The pathogenesis and mechanisms underlying this event are still poorly understood.(2-4) Metastasis is a 'hidden' event, which happens inside the body and is difficult to examine. It is believed to consist of four distinct steps: invasion, intravasation, extravasation, and metastatic colonization. Most carcinoma cells lose their cell-cell contact during the initial step of metastasis and move into the systemic circulation. For this, cells must acquire abilities of migration and invasion, together with cytoskeletal reorganization and active response to their microenvironment. In vivo video microscopy and quantitative approaches show that the first step, the acquisition of invasive ability and motility, is the rate-limiting step in the metastatic cascade (2,5) and clearly indicate that controlling this initial step of metastasis is critical for the development of novel strategies to prevent cancer metastasis. Epithelial-to-mesenchymal transition (EMT), a process vital for morphogenesis during embryonic development, is attracting attention as an important mechanism involved in the initial step of metastasis. During EMT, epithelial cells acquire fibroblast-like properties and show reduced intercellular adhesion and increased motility.(6,7) Conversely, mesenchymal cells possess remarkable plasticity and can eventually regain a fully differentiated epithelial phenotype via a mesenchymalto-epithelial transition (MET). (8,9) Because EMT involves the conversion of a sh...

The aim of this study was to determine if hydrogen peroxide (H2O2) generated by glucose oxidase (GO) induces apoptosis or necrosis of BJAB cells and which radical is the direct mediator of cell death. We found that GO produced H2O2 continuously in low concentrations, similar to in vivo conditions, and decreased proliferation and cell viability in a dose-dependent manner. The GO-mediated cytotoxicity resulted from apoptosis, and was confirmed by monitoring the cells after H33342/Annexin V/propidium iodide staining. Decreases of mitochondrial membrane potential and intracellular glutathione level were found to be critical events in the H2O2-mediated apoptosis. Additional experiments revealed that H2O2 exerted its apoptotic action through the formation of hydroxyl radicals via the Fenton rather than the Haber-Weiss reaction. Moreover, intracellular redox-active iron, but not copper, participated in the H2O2-mediated apoptosis.

Background The Breslow depth is an important parameter to determine the excision margin and prognosis of melanoma. However, it is difficult to accurately determine the actual Breslow depth before surgery using the existing ocular micrometer and biopsy technique. Objectives To evaluate the use of 3D wide‐field multispectral photoacoustic imaging to non‐invasively measure depth and outline the boundary of melanomas for optimal surgical margin selection. Methods Six melanoma patients were examined in vivo using the 3D multispectral photoacoustic imaging system. For five cases of melanomas (one in situ, three nodular, and one acral lentiginous type melanoma), the spectrally unmixed photoacoustic depths were calculated and compared against histopathological depths. Results Spectrally unmixed photoacoustic depths and histopathological depths match well within a mean absolute error of 0.36 mm. In particular, the measured minimum and maximum depths in the in situ and nodular type of melanoma were 0.6 and 9.1 mm, respectively. In the 3D photoacoustic image of one metastatic melanoma, feeding vessels were visualized in the melanoma, suggesting the neovascularization around the tumour. Conclusions The 3D multispectral photoacoustic imaging not only provides well‐measured depth and sizes of various types of melanomas, it also visualizes the metastatic type of melanoma. Obtaining accurate depth and boundary information of melanoma before surgery would play a useful role in the complete excision of melanoma during surgery.

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