In the fabrication of polymeric electroluminescent devices with indium-tin oxide (ITO) as anode, indium contamination of the polymers can greatly degrade the device performance. In the present study, we have used x-ray photoelectron spectroscopy to measure indium incorporation in poly(3,4-ethylene dioxythiophene):poly(styrene sulphonate), referred to as PEDOT:PSS, which were spincast on bare ITO and encapsulated ITO. We found that the deposition of a self-assembled monolayer of alkylsiloxanes on ITO prior to spincasting PEDOT:PSS was effective and practical in blocking the reactions between ITO and PEDOT:PSS.

Objectives: This in vitro study investigated the effects of silver diamine fluoride (SDF) on dentine carious lesion with cariogenic biofilm. Study Design: Thirty human dentine blocks were inoculated with Streptococcus mutans and Lactobacillus acidophilus dual-species biofilm to create carious lesion. They were equally divided into test and control group to receive topical application of SDF and water. After incubation anaerobically using micro-well plate at 37oC for 7 days, the biofilms were evaluated for kinetics, morphology and viability by colony forming units (CFU), scanning electron microscopy (SEM), and confocal microscopy (CLSM), respectively. The carious lesion underwent crystal characteristics analysis, evaluation of the changes in chemical structure and density of collagen fibrils using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and immune-labeling. Results: The log CFU of S. mutans and L. acidophilus in the test group was significantly lower than control group. SEM and CLSM showed confluent biofilm in control group, but not in test group. XRD showed the loss of crystallinity of dentine due to the dissolution of hydroxyapatite crystal structure in test group was less than control group. FTIR showed that log [Amide I: HPO42-] for test vs. control group was 0.31±0.10 vs. 0.57±0.13 (p<0.05). The gold-labeling density in test vs. control group was 8.54±2.44/µm2 vs. 12.91±4.24/µm2 (p=0.04). Conclusions: SDF had antimicrobial activity against the cariogenic biofilms and reduced demineralization of dentine. Key words:Caries, caries arrest, dentine, silver, silver diamine fluoride, fluoride, biofilm,cariogenic.

Practical strongly phosphorescent platinum(II) green to white OLED emitters with bulky tetradentate O^N^C^N ligands.

A series of [(R'-C^N^C-R'')Pt(L)] complexes with doubly deprotonated cyclometalated R'-C^N^C-R'' ligands (R'-C^N^C-R''=2,6-diphenylpyridine derivatives) functionalized with carbazole, fluorene, or thiophene unit(s) have been synthesized and their photophysical properties studied. The X-ray crystal structures reveal extensive intermolecular π···π and C-H···π interactions between the cyclometalated C^N^C ligands. Compared to previously reported cyclometalated platinum(II) complexes [(C^N^C)Pt(L)], which are non-emissive in solution at room temperature, the carbazole-, fluorene- and thiophene-functionalized [(R'-C^N^C-R'')Pt(L)] (L=DMSO 1-9, C≡N-Ar, 1a-9a) complexes are emissive in solution at room temperature with λ(max) at 564-619 nm and Φ=0.02-0.26. The emissions of the [(R'-C^N^C-R'')Pt(L)] complexes are attributed to electronic excited states with mixed (3)MLCT and (3)IL character. The carbazole/fluorene/thiophene unit(s) allow the tuning of the electronic properties of the [(R'-C^N^C-R'')Pt] moiety, with the emission maxima in a range of 564-619 nm. These are the first examples of organoplatinum(II) complexes bearing doubly deprotonated cyclometalated C^N^C ligands that are emissive in solution at room temperature. In non-degassed DMSO, the emission intensities of 6a-9a are enhanced upon exposure to ambient light. This phenomenon is caused by reacting photogenerated (1)O(2) with a DMSO molecule to form dimethyl sulfone, leading to the removal of dissolved oxygen in solution. Self-assembled nanowires and nanorods are obtained from precipitation of 3a in THF/H(2)O and 8a in DMSO/Et(2)O, respectively. The [(R'-C^N^C-R'')Pt(L)] complexes are soluble in common organic solvents with a high thermal stability (>300 °C), rendering them as phosphorescent dopants for organic light-emitting diode (OLEDs) applications. Red OLEDs with CIE coordinates of (0.65±0.01, 0.35±0.01) were fabricated from 7a or 8a. A maximum external efficiency (η(Ext)) of 12.6% was obtained for the device using 8a as emitter.