Solution-Processable Pure Green Thermally Activated Delayed Fluorescence Emitter Based on the Multiple Resonance Effect

Thermally activated delayed fluorescence (TADF) materials based on the multiple resonance (MR) effect are applied in organic light-emitting diodes (OLEDs), combining high color purity and efficiency. However, they are not fabricated via solution-processing, which is an economical approach toward the mass production of OLED displays. Here, a solution-processable MR-TADF material (OAB-ABP-1), with an extended π-skeleton and bulky substituents, is designed. OAB-ABP-1 is synthesized from commercially available starting materials via a four-step process involving one-shot double borylation. OAB-ABP-1 presents attractive photophysical properties, a narrow emission band, a high photoluminescence quantum yield, a small energy gap between S₁ and T₁, and low activation energy for reverse intersystem crossing. These properties are attributed to the alternating localization of the highest occupied and lowest unoccupied molecular orbitals induced by the boron, nitrogen, and oxygen atoms. Furthermore, to facilitate charge recombination, two novel semiconducting polymers with similar ionization potentials to that of OAB-ABP-1 are synthesized for use as interlayer and emissive layer materials. A solution-processed OLED device is fabricated using OAB-ABP-1 and the aforementioned polymers; it exhibits pure green electroluminescence with a small full-width at half-maximum and a high external quantum efficiency with minimum efficiency roll-off.     

Proposal of a risk score for recurrence in patients with curatively resected gastric cancer

In this study, 168 patients who underwent curative resection for gastric cancer with prognostic serosal invasion [ps(+)] and 150 without prognostic serosal invasion [ps(-)] were analyzed separately to determine the prognostic importance of clinicopathological factors, and identify which patients were at high risk of recurrence. A multivariate analysis of survival time using Cox's proportional hazard model revealed the important prognostic factors to be: Lymph node involvement, the classification of gross appearance, macroscopic serosal invasion, and interstitial connective tissue in the ps(+) group; and lymph node involvement, macroscopic serosal invasion, and venous invasion in the ps(-) group. We proposed a risk score of recurrence based on the results of a further multivariate analysis called Hayashi's Quantification Analysis II, in which recurrence was chosen as an objective variable and the above prognostic factors were chosen as explanatory variables. Eighty-four percent of the patients with a score of 0 or higher in the ps(+) group and 83% of those with a score of +6 or higher in the ps(-) group showed recurrence. Thus, we believe that this score is useful for identifying those patients at high risk of recurrence, who should receive intensive chemotherapy even after curative resection.     

Ionic conductivity of polymer electrolytes and future applications

Polymer electrolytes are solvent-free ion-conducting polymers and provide new and attractive materials in both polymer chemistry and electrochemistry. A proper understanding of ion dissociation and ion transport in such polymers is necessary for their application as solid electrolytes in electrochemical devices. Ionic conduction behaviour in polymer electrolytes is described here in relation to the characteristic properties. Of special interest is the ability of polymer electrolytes to include various kinds of electroactive molecules within them. The combination of this ability with their high ionic conductivity has enabled polymer electrolytes to be used as media for electrochemical syntheses and redox reactions.     

Inhibition of growth of the green algaChlorella pyrenoidosa by unsaturated fatty acids

The activity of a number of unsaturated fatty acids in inhibiting the growth of the green algaChlorella pyrenoidosa has been studied using the paper disk-agar plate method. Acrylic and undecylenic acids were highly active, but other θ-unsaturated fatty acids tested were only weakly active. Oleic and elaidic acids were inactive at 0.2 M, but other C₁₈-C₂₂ acids with 2 to 6 double bonds were generally active down to a concentration of 0.01–0.005 M. Activity with chaulmoogric acid was noted down at 0.002–0.001 M. Diffusion rates of the acids through the agar seem to affect the size of the inhibition zones. The implications that polyunsaturated fatty acids may play a role in algal ecology are discussed.     

Relationship between electron sensitivity and chemical structures of polymers as electron beam (EB) resists. V: Polyamides containing sulfur groups as positive eb resists

Polyamidethioethers were synthesized and evaluated as positive electron beam (EB) resists, The polyamidethioethers decomposed easily with EB exposure. At high doses (indicating low sensitivity), crosslinking reactions occurred for polyamidethioethers having C-S bonds produced by Michael addition, but the other polyamidethioethers did not crosslink. The C-S bonds produced by Michael addition may influence crosslinking rather than decomposition. The sensitivity of oxidized polyamidethioether was higher than that of the nonoxidized polymer with no change in resolution. The oxidized polyamidethioether had a high sensitivity and a high resolution, and is adaptable as a positive EB resist.     

Preparation and Properties of Low-Calcium–Content Superconductive Thin Films in Bismuth Systems

Superconductive, polycrystalline thin films from Bi systems with low Ca content in relation to the high- T _c phase and with various Bi(Pb) contents were obtained by two-step annealing of the deposited amorphous films prepared by rf magnetron sputtering. The obtained films, A, B, and C, exhibited a high T _c ( T _c > 100 K) for a wide range of secondary annealing temperatures. The critical current densities of these films at 77.3 K in zero magnetic field were sensitive to the secondary annealing temperature. The highest critical current densities of the films were 27000, 3900, and 5500 A/cm² for films A, B, and C, respectively. Film B exhibited large decreases in critical current density under an applied magnetic field. The grain boundaries of this film, which were composed of PbO, CuO, and Bi₂O₃, apparently acted as weak links in the superconductor materials.     

Glycosylphosphatidylinositol-anchor-deficient mice: implications for clonal dominance of mutant cells in paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic stem cell disorder characterized by complement-mediated hemolysis. Abnormal hematopoietic cells from patients with PNH are deficient in glycosylphosphatidylinositol (GPI)-anchored proteins and clonally dominate various hematopoietic lineages in the bone marrow and the peripheral blood. Analysis of many patients with PNH has showed that somatic mutation in the X-linked gene PIG-A is responsible for the GPI-anchor deficiency in PNH. The PIG-A mutation must also be relevant to the clonal dominance of GPI-anchor deficient (GPI-) blood cells because two or more PIG-A mutant clones become dominant in many patients. However, whether the PIG-A mutation alone is sufficient for clonal dominance is not known. To address this question, we generated chimeric mice using Pig-a (the murine homologue of PIG-A) disrupted embryonic stem (ES) cells, in which the animals are chimeric with respect to the surface expression of GPI-anchored proteins. The chimerism of hematopoietic and nonhematopoietic tissues in such mice was always low, suggesting that the higher contribution of Pig-a disrupted GPI- cells had a lethal effect on the chimera. GPI- cells appeared in the peripheral blood of some of the chimeric mice. However, the percentage of GPI- erythrocytes did not increase for 10 months after birth, implying that the Pig-a mutation alone does not immediately cause the clonal dominance of GPI- blood cells; another pathologic or physiologic change(s) in the hematopoietic environments or in the clone itself may be necessary.     

Effects of canrenoate potassium, an aldosterone antagonist on portal hemodynamics in patients with compensated liver cirrhosis

BACKGROUND/AIMS: Long-term administration of spironolactone is reported to reduce portal pressure in cirrhotic patients. We examined the effects of acute administration of canrenoate potassium, an aldosterone antagonist, on portal hemodynamics in compensated cirrhotic patients using noninvasive duplex Doppler ultrasonography. MATERIALS AND METHODS: Baseline values were obtained in the fasting state, and then 200mg of canrenoate potassium in 10ml of saline solution was intravenously administered to 22 patients, whereas 10ml of saline solution was administered as a placebo to 8 patients. RESULTS: The portal cross-sectional area, portal blood velocity and portal blood flow decreased by 5.3 +/- 9.2, 10.4 +/- 8.7% and 13.0 +/- 12.4%, respectively at the nadir 60min after administration and these decreases persisted until 120min. Placebo did not affect these parameters of portal hemodynamics. Eleven responders, who had a more than 10% drop in portal blood flow 60min after administration, had significantly higher levels of plasma aldosterone than 8 non responders who had less than 10% drop. The reduction rate of portal blood flow was closely correlated with plasma aldosterone level. CONCLUSIONS: These findings suggest that aldosterone antagonist directly causes a reduction in portal blood flow, probably through inhibition of aldosterone-induced vasoconstrictive action.     

Not Oligomers but Amyloids are Cytotoxic in the Membrane‐Mediated Amyloidogenesis of Amyloid‐β Peptides

The formation of neurotoxic aggregates by amyloid‐β peptide (Aβ) is considered to be a key step in the onset of Alzheimer's disease. It is widely accepted that oligomers are more neurotoxic than amyloid fibrils in the aqueous‐phase aggregation of Aβ. Membrane‐mediated amyloidogenesis is also relevant to the pathology, although the relationship between the aggregate size and cytotoxicity has remained elusive. Here, aggregation processes of Aβ on living cells and cytotoxic events were monitored by fluorescence techniques. Aβ formed amyloids after forming oligomers composed of ≈10 Aβ molecules. The formation of amyloids was necessary to activate apoptotic caspase‐3 and reduce the ability of the cell to proliferate; this indicated that amyloid formation is a key event in Aβ‐induced cytotoxicity.