Background
Gastric cancers have been recently classified in accordance with their molecular characteristics, thus demonstrating the complex nature of cancers and an association with the immune ...contexture within the tumor microenvironment. This study aimed to investigate the correlation between the molecular subtype and immune contexture of gastric cancers.
Methods
The immune contexture, including the type, density, and location of tumor-infiltrating lymphocytes (TILs), of gastric cancer patients was examined and immune subtypes were classified based on it. In particular, PD-L1 expression on tumor cells and TILs and Foxp3
+
TILs was assessed in accordance with molecular subtypes.
Results
High levels of visual TIL estimates and Foxp3
+
TILs were markedly associated with increased overall survival (
P
= 0.001,
P
< 0.001, separately). Immune subtypes were associated with tumor size, gross type, depth of invasion, lymph node metastatic status, lymphovascular invasion, perineural invasion, and microsatellite instability status. EBV-positive (C1) and MSI (C2) gastric cancers, considered subtypes with better prognosis, were significantly associated with high TIL levels (
P
< 0.05). In contrast, epithelial–mesenchymal transition (EMT, C3) gastric cancers with poor overall survival displayed low levels of Foxp3
+
TILs. Type II tumors (low level of TILs/low PD-L1 expression) displayed a significant correlation with poor overall survival (
P
= 0.004) and accounted for the highest proportion in the aberrant p53-expressing (C4) gastric cancers.
Conclusion
The molecular subtype of gastric cancers is correlated with the immune subtype, including immune contexture and PD-L1 expression, within the tumor microenvironment.
In this study, we investigated the solid-state weldability of Ti alloys with commercial purity (grade 2). First, as a solid-state welding approach, we conducted friction welding at a rotation speed ...of 1600 rpm and a friction pressure of 15 kgf on rod-type specimens with a size of 15 mm (dia.) × 50 mm (length). Subsequently, the grain boundary characteristic distributions such as the grain size, shape, orientation, and misorientation angle of the welds were clarified by means of the electron backscatter diffraction method. To study the mechanical properties of the welds, we conducted Vickers microhardness and tensile tests. We found that the application of friction welding to Ti alloy led to a significantly refined grain size in the weld zone (0.84 μm) relative to that in the base material (11.4 μm), accompanied by an orientation change from in the base material to <2–1–10> in the weld zone. In addition, the mechanical properties of the welds were more enhanced than those of the base material: the microhardness and yield strength of the weld were approximately 20% and 2% higher, respectively, than those of base material. These enhanced mechanical properties are mainly due to grain refinement and orientation development during welding.
In this study, we report an accurate and more reliable approach to estimate the dipole orientation of emitters especially phosphorescence, fluorescence and even thermally activated delayed ...fluorescence. The dipole orientation measurements are performed by examining the variation of the photoluminescence (PL) exciton decay rate from time-resolved PL and optical analysis. Our anisotropic dipole orientation results are consistent with those of previous reports. The studied measurement approach is very reliable and accurate to estimate the dipole orientation of any organic semiconductor materials regardless of whether they are doped or neat films.
In this study, we report an accurate and more reliable approach to estimate the dipole orientation of emitters especially phosphorescence, fluorescence and even thermally activated delayed fluorescence.
The electroluminescence characteristics of pristine and degraded organic light‐emitting diode (OLED) devices are studied using the time‐resolved electroluminescence (TREL) technique. It is found that ...materials degradation results in notable changes in the temporal profile of TREL curve, which involves a shorter onset time, a longer rise time, and a longer decay time of electroluminescence. It is found that these temporal characteristics are affected by trapped charges formed during the OLED operation. More detailed analysis reveals that there are two types of charge traps. The longer decay time is found to be due to the excitons produced by weakly bound charges trapped in the organic layer that are released by thermal energy even without applying the voltage pulse. In contrast, the shorter onset time of electroluminescence is due to the excitons from strongly bound charges that can be released only when a voltage pulse is applied. It is demonstrated that TREL can be used to investigate the underlying mechanisms of OLED degradation. The presence of different types of charge traps found in this study may prove useful for more elaborate design of OLED devices toward enhanced durability against degradation and higher duty cycle of device operation.
Degradation of organic light‐emitting diode results in notable changes in time‐resolved electroluminescence curves. The trapped charges formed during degradation cause a shortened onset time, a longer rise time, and a longer decay time of electroluminescence. There are two types of charge traps, one of which is to lengthen a decay time and the other which shortens an onset time.
•A new hole-transporting material (TPDI) for OLED applications.•A proper HOMO level (5.3eV) and high hole mobility (6.14×10−3cm2/Vs) of TPDI.•>1.0V driving voltage reduction and >30% improved EQEs by ...TPDI in blue fl. and green ph. OLEDs.
A new hole-transporting material, 5,10,15-triphenyl-5H-diindolo3,2-a:3′,2′-ccarbazole (TPDI) is reported for organic light-emitting device (OLED) applications. It shows excellent hole mobility (6.14×10−3cm2/Vs), one order higher than that of NPB (4,4′-bis(N-phenyl-1-naphthylamino)biphenyl), and a good HOMO level of 5.3eV. Fabricated fluorescent blue OLEDs exhibit about 1.0V voltage reduction and 18% external quantum efficiency (EQE) improvement by replacing TPDI instead of NPB as a hole transport layer. In the green phosphorescent OLEDs, the driving voltage improves about 1.8V and EQE increases about 65%. This TPDI will be applicable to not only in fluorescent OLEDs but also in phosphorescent OLEDs.
Highly efficient single-stack hybrid cool white organic light-emitting diodes (OLEDs) having blue-yellow-blue multiple emitting layers (EMLs) are designed and constructed by utilizing blue thermally ...activated delayed fluorescent (TADF) and yellow phosphorescent emitters. The out-coupling efficiencies of yellow and blue emissions are maximized by tuning the ITO and total device thickness that satisfies both of antinode positions for yellow and blue emissions in a limited multiple EML thickness. To obtain a cool white emission, the exciton formation ratio in the blue-yellow-blue multiple EML system is controlled by manipulating the recombination zone through charge conductivity variation of host medium in the blue TADF EML. The resulting device exhibits cool white emission with very high maximum external quantum efficiency of 23.1% and CIE color coordinates of (0.324, 0.337). We anticipate that the studied approach will raise the viability of single-stack hybrid cool white OLEDs for high performance display applications.
Transparent organic light emitting diodes (TOLED) have widespread applications in the next-generation display devices particularly in the large size transparent window and interactive displays. ...Herein, we report high performance and stable attractive smart window displays using facile process. Advanced smart window display is realized by integrating the high performance light blocking screen and highly transparent white OLED panel. The full smart window display reveals a maximum transmittance as high as 64.2% at the wavelength of 600 nm and extremely good along with tunable ambient contrast ratio (171.94:1) compared to that of normal TOLED (4.54:1). Furthermore, the performance decisive light blocking screen has demonstrated an excellent optical and electrical characteristics such as i) high transmittance (85.56% at 562nm) at light-penetrating state, ii) superior absorbance (2.30 at 562nm) in light interrupting mode, iii) high optical contrast (85.50 at 562 nm), iv) high optical stability for more than 25,000 cycle of driving, v) fast switching time of 1.9 sec, and vi) low driving voltage of 1.7 V. The experimental results of smart window display are also validated using optical simulation. The proposed smart window display technology allows us to adjust the intensity of daylight entering the system quickly and conveniently.
Understanding the exciton energy transfer and bi-exciton annihilation processes in the emitting layers (EMLs) of thermally activated delayed fluorescence (TADF)-based organic light-emitting diodes ...(OLEDs) is essential for improving their internal quantum efficiency and efficiency roll-off. To study the energy transfer among dopant molecules in EMLs, time-resolved fluorescence (TRF) anisotropy decay measurements were conducted with DPEPO(host):TDBA-DI(dopant) films having different dopant concentrations. Subsequently, the bi-exciton annihilation processes in the DPEPO:TDBA-DI films were studied using time-resolved photoluminescence (TRPL) and excitation power-dependent photoluminescence (PL) experiments. The rate constants for the triplet-triplet annihilation in the films were large at high concentrations of the dopant in the films. The excitation power-dependent PL experiments showed that the laser power threshold for the onset of the bi-exciton annihilation decreased as the dopant concentration increased. Finally, molecular dynamics (MD) simulation and the hybrid Monte Carlo method were applied to understand the energy transfer dynamics at the molecular level. The MD simulation results well supported the results of TRF anisotropy decay measurements. Our current experimental and computational methods can be effectively utilized to understand the exciton dynamics in EMLs, and provide insights into the design of EMLs by optimizing the exciton energy transfer and minimizing undesired bi-exciton annihilation processes in TADF-based OLEDs.
Time-resolved fluorescence anisotropy measurements and molecular dynamics simulations are used to study the energy transfer among dopant molecules in the emitting layer of organic light emitting diodes.
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