Synthesis, Photoluminescence, and Electroluminescence of Phosphorescent Dipyrido[3,2-a;2'3'-c]phenazine-Platinum(II) Complexes Bearing Hole-Transporting Acetylide Ligands.

In this study, novel phosphorescent dipyrido[3,2-a;2'3'-c]phenazine (dppz)-platinum(II)-phenylacetylide complexes were developed to fabricate non-doped organic light-emitting diodes (OLED) by solution-processing. To facilitate the charge carrier injection into the emitting layer (EML), 3,6-di-tert-butylcarbazole-functinalized phenylacetylides were employed. As for the dppz ligand, 9,9-dihexylfluoren-2-yl and 4-hexylthiophen-2-yl side-arms were introduced to the 2,7-positions, which led to reddish orange and red photoluminescence (PL), respectively, in solution and film states (PL wavelength: ca. 600 and ca. 625 nm, respectively). The carbazole-appended phenylacetylide ligands hardly affected the emission color, although unsubstituted phenylacetylides gave rise to aggregate- or excimer-based near-infrared PL with a low quantum yield. Two types of non-doped OLEDs were fabricated: single-layer and multilayer devices. In both devices, the organic layers were fabricated by spin-coating, and the EML consisted of a neat film of the corresponding platinum(II) complex. Therein, electroluminescence spectra corresponding to those of PL were observed. The single-layer devices exhibited low device efficiencies due to a deteriorated charge carrier balance. The multilayer devices possessed hole- and electron-transporting layers on the anode and cathode sides of the EML, respectively. Owing to an improved charge carrier balance, the multilayer devices exhibited higher device performance, affording considerably improved values of luminance and external quantum efficiency.

Preserving the Ankle by the Masquelet Technique for the Large Bone Defect in the Distal Tibia in Children: A Case Report.

CASE: A 14-year-old adolescent girl sustained an open fracture of the foot after jumping off a building. Initial radiographs revealed large bone defect in the distal metaphysis of the comminuted tibia. The comminuted distal tibia was reconstructed by external fixation and internal fixation with bridge plating, followed by the Masquelet technique. After 12 months, the fracture healed without infection, and the patient could walk independently. CONCLUSION: In the case of a comminuted fracture of the contaminated distal tibia with a large bone defect, plate fixation and the Masquelet technique produced good outcomes.

Supramolecular Gel Phase Controlled [4 + 2] Diels-Alder Photocycloaddition for Electroplex Mediated White Electroluminescence.

Diels-Alder photocycloaddition of 9-phenylethynylanthracene results in multiple [4 + 2] and [4 + 4] cycloaddition products in solution, which can be controlled to form specific products under a restricted environment. We have exploited the gel phase of a 9-phenylethynylanthracence derivative as a confined medium to specifically yield the [4 + 2] cycloadduct in >90% yield. The photocycloadduct ( anti-form) exhibited a blue emission with CIE chromaticity of x = 0.16/ y = 0.16. Construction of an organic light emitting device with the photocycloadduct, using a carbazole-based hole transporting host, resulted in white light emission with a CIE chromaticity of x = 0.33/ y = 0.32. This observation not only highlights the use of gel chemistry to achieve the otherwise difficult to obtain photoproducts but also underlines their potential in optoelectronic device fabrication.

Photokinetic study on remarkable excimer phosphorescence from heteroleptic cyclometalated platinum(ii) complexes bearing a benzoylated 2-phenylpyridinate ligand.

Novel heteroleptic cyclometalated platinum(ii) complexes consisting of 5'-benzoylated 2-phenylpyridinate (ppy) cyclometalated and acetylacetonate ancillary ligands were synthesized, and their photoluminescence (PL) properties were investigated. The 5'-benzoylated complex without any other substituents exhibited phosphorescence-based monomer emission at 479 nm in dichloromethane (10 µM, rt) with a PL quantum yield of 0.28. On the other hand, in poly(methyl methacrylate) (PMMA) film, remarkable excimer emission additionally emerged at ca. 600 nm with a relatively high PL quantum yield of 0.47 as the doping level increased to 0.20 mmmol g-1, which was comparably intense in comparison with the monomer emission. In the case of the complexes with unsubstituted, 4'-benzoylated, and 5'-fluorinated ppy cyclometalated ligands, excimer emission was modestly generated at the same doping level, and thus the introduction of a benzoyl group to the 5'-position is effective to obtain remarkable excimer emission. The combination of benzoyl and fluoro groups was more effective at inducing excimer emission, and the intensity of excimer emission of the 2-(5-benzoyl-4,6-difluorophenyl)pyridinate-based complex was 3.5 times larger than that of monomer emission at a doping level of 0.20 mmmol g-1 in PMMA. From the analysis of PL lifetimes at varying concentrations, photokinetic profiles were fully analyzed according to the model system for the irreversible excimer formation, and the excimer formation rate constant of the 5'-benzoylated complex was determined in dichloromethane as 2.2 × 109 M-1 s-1, which is 4.4 times larger than that of the unsubstituted complex. We also fabricated an organic light-emitting diode using the 2-(5-benzoyl-4,6-difluorophenyl)pyridinate-based complex as a single emitter. The device exhibited pseudo-white EL with the Commission internationale de l'éclairage chromaticity coordinates of (0.42, 0.42).

Antiangiogenic activity of flavonoids from Melia azedarach.

Three flavonoid glycosides, 1 (rutin: quercetin 3-O-rutinoside), 2 (kaempferol 3-O-robinobioside) and 3 (kaempferol 3-O-rutinoside) were isolated from the subcritical water extracts of Melia azedarach leaves. Strong antiangiogenic activity of these compounds was observed in the in vivo assay using the chorioallantoic membrane (CAM) from growing chick embryos.

Mislocalization or low expression of mutated Shwachman-Bodian-Diamond syndrome protein.

Shwachman-Diamond syndrome (SDS) is an autosomal-recessive disorder characterized by exocrine pancreatic insufficiency and bone marrow failure. Mutations in the SBDS gene are identified in most patients with SDS. Recent studies have shown that SBDS is involved in ribosome biogenesis and is localized to the nucleolus. The significance of cellular localization in SBDS is unknown, particularly as SBDS does not exhibit canonical nuclear localization signals. In this study, we have constructed wild-type deletion mutants of the critical domains and disease-associated mutants of the SBDS gene. These constructs were expressed in HeLa cells to explore the subcellular distribution of normal and mutant proteins. Wild-type SBDS was detected in the nucleus. However, constructs lacking N-terminal Domain I and two disease-associated mutants (C31W and N34I) failed to localize SBDS to the nucleus. Moreover, the amount of mutated SBDS protein was decreased. When N-terminal Domain I was overexpressed in HeLa cells, the localization of endogenous SBDS protein was changed from nuclei to cytosolic fraction. These data indicate that the N-terminal Domain I is responsible for nuclear localization. Furthermore, low expression of SBDS, as exhibited in some of the disease-associated mutants, may be associated with the pathogenesis of SDS.

Shwachman-Diamond syndrome is not necessary for the terminal maturation of neutrophils but is important for maintaining viability of granulocyte precursors.

OBJECTIVE: Shwachman-Diamond syndrome (SDS) is an autosomal-recessive disorder characterized by exocrine pancreatic insufficiency and bone marrow failure. The SDS disease locus was mapped to chromosome 7q11, and disease-associated mutations were reported in the Shwachman-Bodian-Diamond syndrome (SBDS) gene. SBDS is a member of a highly conserved protein family in diverse species including archaea and eukaryotes. It is widely expressed in many tissues, and its function is still unknown. To investigate the function of the SBDS protein, we undertook loss-of-function experiments in the 32Dcl3 cell line, which has the potential to differentiate to mature neutrophils. METHODS: SBDS gene was downregulated with lentivirus-based RNAi system. SBDS knockdown cells were analyzed for surface marker expression by flow cytometry and analyzed for the sensitivity to apoptosis-inducing stimuli. RESULTS: After culture in granulocyte colony-stimulating factor (G-CSF)-containing medium for 3 days, 32Dcl3 cells demonstrated normal proliferation but complete downregulation of SBDS protein expression. The SBDS RNAi knockdown cells did not proliferate in G-CSF-containing medium but after 7 days had the appearance of segmented neutrophils. The neutrophil maturation markers were detected on these cells. Undifferentiated SBDS RNAi knockdown cells demonstrated increased apoptosis of undifferentiated cells. Notably, SBDS RNAi knockdown cells demonstrated normal proliferation in interleukin-3-containing medium. CONCLUSION: We have established an SDS model cell line and have used this model to demonstrate that SBDS is not required for neutrophil maturation. However, SBDS knockdown cells were sensitive to apoptotic stimuli, indicating that SBDS acts to maintain survival of granulocyte precursor cells.

The effect of anionic amphiphiles on the recruitment of Rac in neutrophils.

Anionic amphiphiles have been shown to influence the NADPH oxidase system. Although one target of the amphiphile action is p47(phox), the cell-free activation of the enzyme in the absence of p47(phox) is also influenced. In the present study, we examined the actions of sodium dodecyl sulfate (SDS) on the NADPH oxidase system in vivo. Treatment of guinea pig neutrophils with the amphiphile caused the translocation of Rac to a membrane fraction and its conversion to the GTP-bound form. Because SDS had little effect on p47(phox), it increased the superoxide production only when p47(phox) was otherwise activated. Inhibitors of phosphoinositide 3-kinases had no effect on the SDS-induced translocation of Rac to the membrane. However, the inhibitors prevented the conversion of Rac to its GTP-bound form, indicating that these two processes can be controlled separately. In a cell-free system, SDS induced the binding of p47(phox) and Rac to the membrane preparation. The SDS concentration inducing the Rac binding was lower than that inducing the p47(phox) binding. Thus we observed that Rac is more sensitive to SDS than p47(phox) both in vivo and in vitro. The results suggest a role of natural amphiphiles such as unsaturated fatty acids in regulation of Rac activation.

Case report: case of clear cell sarcoma surviving with the primary lesion for 20 years after resection of a metastatic lymph node.

In this paper we report on an extremely rare case of clear cell sarcoma, which is a rare malignant soft tissue tumor, biologically similar to malignant melanoma. The patient has survived for 25 years after he noticed a small tumor mass at the wrist and for 20 years after a small sentinel lymph node metastasis in the axilla was removed by surgical resection. The patient visited us because the tumor in his wrist had increased rapidly in size during the previous year. We diagnosed the wrist tumor as a clear cell sarcoma, based on the typical histopathological findings and positivity of the tumor cells for HMB-45 and S-100 protein; the histopathological findings in the axillary soft tissue tumor resected 20 years previously were also compatible with clear cell sarcoma of the lymph node. Therefore, we concluded that the wrist tumor was the primary lesion of clear cell sarcoma and that the axillary tumor was a metastatic lesion in a sentinel lymph node. Generally, the prognosis of clear cell sarcoma is very poor, especially after the occurrence of lymph node metastasis. In this case, it is possible that certain immune mechanisms played a role in effectively suppressing the tumor growth for such a prolonged period, even after the development of lymph node metastasis.