Highly efficient deep‐blue fluorescent materials based on phenylquinoline–carbazole derivatives (PhQ‐CVz, MeO‐PhQ‐CVz, and CN‐PhQ‐CVz) are synthesized for organic light‐emitting diodes (OLEDs). The ...materials form high‐quality amorphous thin films by thermal evaporation and the energy levels can be easily adjusted by the introduction of different electron‐donating and electron‐withdrawing groups on carbazoylphenylquinoline. Non‐doped deep‐blue OLEDs that use PhQ‐CVz as the emitter show bright emission (Commission Internationale de L'Éclairage (CIE) coordinates, x = 0.156, y = 0.093) with an external quantum efficiency of 2.45%. Furthermore, the material works as an excellent host material for 4,4′‐bis(9‐ethyl‐3‐carbazovinylene)‐1,1′‐biphenyl dopant to get high‐performance OLEDs with excellent deep‐blue CIE coordinates (x = 0.155, y = 0.157), high power efficiency (5.98 lm W−1), and high external quantum efficiency (5.22%).
Deep‐blue light‐emitting organic materials are still rare. Here, deep‐blue fluorescent emitters based on phenylquinoline–carbazole derivatives are synthesized for organic light‐emitting diodes (OLEDs). Multilayered OLEDs are fabricated with these materials as the emitting layer (non‐doped OLEDs) or as the host for BCzVBi dopant (doped OLEDs). The devices exhibit deep‐blue emission with high efficiencies (see figure).
Background
Stratification of patients who undergo curative resection for early gastric cancer (EGC) is warranted due to the heterogeneity in the risk of developing extragastric recurrence (EGR). ...Therefore, we aimed to stratify the need for postoperative surveillance for EGR detection in patients with EGC by developing a model for predicting EGR-free survival.
Methods
This retrospective cohort study included patients who underwent postoperative surveillance after curative resection of EGC (
n
= 4149). Cox proportional hazard models were used to identify predictors to build a model for predicting EGR-free survival. Bootstrap-corrected c-index and calibration plots were used for internal and external (
n
= 2148) validations.
Results
A risk-scoring system was constructed using variables significantly associated with EGR-free survival: pathologic T stage (pT1bsm1, hazard ratio HR 4.928; pT1bsm2, HR 5.235; pT1bsm3, HR 7.748) and N stage (pN1, HR 4.056; pN2, HR 9.075; pN3, HR 30.659). Patients were dichotomized into a very-low-risk group or a low-or-greater-risk group. The 5-year EGR-free survival rates differed between the two groups (99.9 vs. 97.3%). The discriminative performance of the model was 0.851 (Uno’s c-index) and 0.751 in the internal and external cohorts, respectively. The calibration slope was 0.916 and 1.131 in the internal and external cohorts, respectively.
Conclusions
Our model for predicting EGR-free survival based on the pathologic T and N stages may be useful for stratifying patients who have undergone curative surgery for EGC. The results suggest that patients in the very-low-risk group may be spared from postoperative surveillance considering their extremely high EGR-free survival rate.
위장관 출혈의 영상의학적 진단법
Journal of the Korean Society of Radiology,
05/2023, Volume:
84, Issue:
3
Journal Article
Peer reviewed
Open access
위장관 출혈은 단일 질환이 아니라 광범위한 위장 질환의 증상 및 임상적 발현이다. 임상적 양상에 따라 명백한 출혈, 잠재 출혈, 원인 불명 출혈로 나눌 수 있으며, 출혈 위치에 따라 Treiz 인대를 기준으로 상부 또는 하부 위장관 출혈로 분류할 수 있다. 혈관 질환, 용종, 종양, 크론병, 이소성 췌장 및 이소성 위조직 등 다양한 질환이 위장관 출혈을 ...일으킬 수 있다. 명백한 출혈을 위한 영상 검사기법은 CT 혈관조영술, 고식적 혈관조영술 및 핵의학적 검사 등이 사용된다. 잠재 위장관 출혈을 평가하기 위한 영상검사로는 CT 소장조영술이 주로 사용되며, 위장관을 적절히 팽창해서 영상을 획득해야 위음성 혹은 위양성을 최소화하여 진단능을 높일 수 있다. CT 소장조영술에서 진단이 확실하지 않은 경우, Meckel scan이 보완적으로 사용될 수 있다. 원인 불명 위장관 출혈에 대한 검사는 임상 양상과 임상의 혹은 영상의학과 의사의 선호도에 따라 다양한 검사가 시행될 수 있으며, 이에 대한 추가적인 연구가 필요하다.
The supergiant VX Sagittarii is a strong emitter of both H2O and SiO masers. However, previous VLBI observations have been performed separately, which makes it difficult to spatially trace the ...outward transfer of the material consecutively. Here we present the astrometrically registered, simultaneous maps of 22.2 GHz H2O and 43.1/42.8/86.2/129.3 GHz SiO masers toward VX Sagittarii. The H2O masers detected above the dust-forming layers have an asymmetric distribution. The multi-transition SiO masers are nearly circular ring, suggesting spherically symmetric wind within a few stellar radii. These results provide the clear evidence that the asymmetry in the outflow is enhanced after the smaller molecular gas clump transform into the inhomogeneous dust layers. The 129.3 GHz maser arises from the outermost region compared to that of 43.1/42.8/86.2 GHz SiO masers. The ring size of the 129.3 GHz maser is maximized around the optical maximum, suggesting that radiative pumping is dominant.
Iridium complexes containing cyclometalated 2‐cyclohexenylpyridine derivatives with rigid and bulky cyclohexene units are synthesized, and found to be highly efficient materials in EL devices (see ...figure). Devices based on these iridium complexes emit yellowish‐ green light with the very high external quantum efficiency of 18.7%.
Objectives
To determine the correlation between iodine concentrations derived from dual-energy CT (DECT) and perfusion CT (PCT) parameters in patients with pathologically proven colorectal cancers ...(CRC) and to evaluate their reproducibility and respective radiation exposures.
Methods
Institutional review board approval and written informed consents were obtained for this study. Forty-one patients with CRCs who underwent same-day DECT and PCT were prospectively enrolled. Three radiologists independently analyzed the iodine concentration of the tumors and iodine ratios ratio of lesion to aorta (IRa) or to infrarenal IVC (IRv) from DECT as well as blood flow (BF), blood volume (BV), permeability (PMB), and mean transit time (MTT) from PCT. Pearson
R
and linear correlation, paired t-test, and intraclass correlation coefficients (ICCs) were used.
Results
Significant correlations were found between iodine parameters from DECT and PCT parameters: iodine concentration of tumors and BV (
r
= 0.32,
p
= 0.04), PMB (
r
= 0.34,
p
= 0.03), and MTT (
r
= -0.38,
p
= 0.02); iodine ratio (IRa) and MTT (
r
= -0.32,
p
= 0.04); iodine ratio (IRv) and BF (
r
= 0.32,
p
= 0.04) and PMB (
r
= 0.44,
p
= <0.01). DECT showed better intra- and interobserver agreements (ICC = 0.98, 0.90 in iodine concentration; 0.98, 0.91 in IRa; and 0.91, 0.93 in IRv, respectively) than PCT (ICC = 0.90, 0.78 in BF; 0.82, 0.76 in BV; 0.75, 0.75 in PMB; 0.64, 0.79 in MTT, respectively). As for radiation dosage, CTDIvol and DLP in DECT (10.48 ± 1.84 mGy and 519.7 ± 116.7 mGy·cm) were significantly lower than those of PCT (75.76 mGy and 911 mGy·cm) (
p
< 0.01).
Conclusion
Iodine parameters from DECT are significantly correlated with PCT parameters, but have higher intra- and interobserver agreements and lower radiation exposure.
Key Points
• Quantitative iodine concentrations from DECT are significantly correlated with perfusion CT parameters.
• Intra- and interobserver agreements of DECT are better than those of perfusion CT.
• Effective radiation doses of DECT are significantly lower than those of perfusion CT.
• DECT can be used as an alternative to perfusion CT with lower radiation doses.
Simultaneous monitoring observations of H2O 61,6 − 52,3 and SiO v = 1, 2, J = 1 → 0, v = 1, J = 2 → 1, J = 3 → 2 masers were performed toward the suspected D-type symbiotic star V627 Cas from 2011 ...October to 2020 March using the Korean Very Long Baseline Interferometry (VLBI) Network (KVN) single-dish telescopes. All spectra of the H2O masers showed highly redshifted emissions with respect to the stellar velocity of −52 km s−1 with high asymmetries. In addition, the spectra of the H2O maser showed three components which varied according to observational dates. On the other hand, the SiO v = 1, 2, J = 1 → 0 and v = 1, J = 2 → 1 masers exhibited a predominantly blueshifted emission in most epochs. The SiO v = 1, J = 3 → 2 maser has arisen around the stellar velocity from 2016 November 19 and shows a predominantly redshifted emission from 2018 June 15. We analyze time variations of the H2O and SiO maser intensities, their intensity ratios, peak and mean velocities, and full width zero power. Based on these analyses, the asymmetries of the H2O and SiO masers’ spectra in V627 Cas and the variation characteristics of the maser properties of the different maser lines are discussed. As a possible cause of asymmetries, the influence of a hot component located at the eastern part of the red giant can be suggested based on the KVN VLBI results. The differences in the variation characteristics of the maser properties may originate from the differences in their locations and excitation conditions.
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