Facile Generation of Thermally Activated Delayed Fluorescence and Fabrication of Highly Efficient Non-Doped OLEDs Based on Triazine Derivatives.

A series of donor-acceptor-donor triazine-based molecules with thermally activated delayed fluorescence (TADF) properties were synthesized to obtain highly efficient blue-emitting OLEDs with non-doped emitting layers (EMLs). The targeted molecules use a triazine core as the electron acceptor, and a benzene ring as the conjugated linker with different electron donors to alternate the energy level of the HOMO to further tune the emission color. The introduction of long alkyl chains on the triazine core inhibits the unwanted intermolecular D-D/A-A-type π-π interactions, resulting in the intermolecular D-A charge transfer. The weak aggregation-caused quenching (ACQ) effect caused by the suppressed intermolecular D-D/A-A-type π-π interaction further enhances the emission. The crowded molecular structure allows the electron donor and acceptor to be nearly orthogonal, thereby reducing the energy gap between triplet and singlet excited states (ΔEST ). As a result, blue-emitting devices with TH-2DMAC and TH-2DPAC non-doped EMLs showed satisfactory efficiencies of 12.8 % and 15.8 %, respectively, which is one of the highest external quantum efficiency (EQEs) reported for blue TADF emitters (λpeak <475 nm), demonstrating that our tailored molecular designs are promising strategies to endow OLEDs with excellent electroluminescent performances.

Diagnosis of Congenital Coarctation of the Aorta and Accompany Malformations in Infants by Multi-Detector Computed Tomography Angiography and Transthoracic Echocardiography: A Chinese Clinical Study.

BACKGROUND The purpose of this study was to evaluate the utility of multi-detector computed tomography (MDCT) angiography and transthoracic echocardiography (TTE) in the diagnosis of congenital coarctation of the aorta (CoA) and accompanying malformations in infants. MATERIAL AND METHODS From January 2012 and December 2015, we enrolled 68 infants with clinically suspected CoA who underwent MDCT angiography and TTE in our hospital. Surgical correction was conducted to confirm the diagnostic accuracy of both examinations in all patients. RESULTS In this study, the diagnosis of CoA was confirmed infants by surgical results in 55 of 68 infants. The diagnostic accuracy, sensitivity, and specificity of MDCT angiography were 95.6%, 96.4%, and 92.3%, respectively. The diagnostic accuracy, sensitivity, and specificity of TTE were 88.2%, 90.9%, and 76.9%, respectively. There was no significant difference in diagnostic accuracy, sensitivity, and specificity between MDCT angiography and TTE (χ²=2.473, p>0.05, χ²=1.373, p>0.05 and χ²=1.182, p>0.05, respectively). In the diagnosis of concomitant cardiac abnormalities with CoA, the 2 methods also play different roles. CONCLUSIONS MDCT angiography and TTE play different roles in the diagnosis of CoA and accompany malformations. MDCT angiography in the diagnosis of the extra-cardiac vascular malformations is better than TTE, and TTE is superior to MDCT angiography in diagnosing intracardiac malformation. Combined MDCT angiography and TTE is a relatively valuable, reliable, and noninvasive method in the diagnosis of CoA and accompany malformations in infants.

[MRI image analysis of 1,2-dichloroethane chronic toxic encephalopath].

OBJECTIVE: To study the MRI features of 1,2-dichloroethane Chronic Toxic Encephalopathy of 10 cases. METHOD: 10 cases were examined by MRI, slice thickness 8 mm, layer from 2 mm, axial and coronal line scan, T1WI, T2WI, FLAIR imaging. RESULTS: 10 cases show varying degrees of abnormal signal of white matters, low signal intensity on T1WI, high signal intensity on T2WI and FLAIR. MRI could also show extensive abnormal signal in cerebral white matter although the toxic manifestation is mild to moderate. Therefore the symptoms and the shows of MRI could be inconsistent. CONCLUSION: Combined with a history of exposure, the show of varying degrees of abnormal signal of white matter in 1,2-dichloroethane Chronic Toxic Encephalopathy cases are characteristic.

Variation of soil bacterial diversity after the invasion of Phyllostachys edulis into Pinus massoniana forest.

To identify the variation in soil bacterial community diversity brought by the invasion of Phyllostachys edulis into Pinus massoniana forest, we collected mixed soil samples from three types of forests, including a pure Ph. edulis forest, a mixed Ph. edulis and conifers (P. massoniana) fore-st, and a mixed forest of evergreen broadleaves and conifers. Samples were analyzed by high-throughput sequencing for measuring the soil bacterial community diversity and structure. The results showed that the bacterial communities comprised of 511 genera, 160 families, 134 orders, 88 classes, and 39 phyla. The proportion of Acidobateria in the pure Ph. edulis forest was significantly lower and the proportions of Actinobacteria, Bacteroidetes, TM7, and Chlamydiae were significantly higher than that in other forests. Meanwhile, various genera showed significant differences in proportions in both the mixed forests when compared with their corresponding proportions in the pure Ph. edulis forest. There were 130 non-dominant genera presented alone in each of the two mixed forests, at proportions between 0.005% and 0.1%. The pure Ph. edulis forest had the lowest &Agr; diversity, while that of the mixed Ph. edulis and evergreen broadleaf forest was intermediate, and that of the mixed evergreen broadleaf and coniferous forest was the highest. The index of &Agr; diversity followed evergreen coniferous mixed forest > bamboo needle mixed forest > pure bamboo forest, and the diffe-rence between the mixed Ph. edulis and evergreen broadleaf forest and the mixed evergreen broadleaf and coniferous forest was insignificant. The PCoA results revealed that the invasion of Ph. edulis affected the population diversity and community structure of soil bacteria. There was a significant correlation between the percentage of non-dominant bacterial phyla in the soil (less than 0.1% of the proportion) and the soil environmental gradient such as water-soluble organic nitrogen and nitrate. Water-soluble organic nitrogen and nitrate had strong effects on the non-dominant bacterial population in the soil following the invasion of Ph. edulis into the P. massoniana forest. These findings would serve as important references for further related studies.

Preoperative evaluation value of aortic arch lesions by multidetector computed tomography angiography in type A aortic dissection.

The purpose of this study was to preoperatively evaluate the value of aortic arch lesions by multidetector computed tomography (MDCT) angiography in type A aortic dissection (AD).From January 2013 to December 2015, we enrolled 42 patients with type A AD who underwent MDCT angiography in our hospital. The institutional database of patients was retrospectively reviewed to identify MDCT angiography examinations for type A AD. Surgical corrections were conducted in all patients to confirm diagnostic accuracy.In this study, the diagnostic accuracy of MDCT angiography was 100% in all 42 patients. The intimal tear site locations that were identified in patients included the ascending aorta (n = 25), aortic arch (n = 12), and all other sites (n = 5). Compared with the control group, there were significant differences in the aortic arch anatomy among the cases. Regarding the distance between the left common carotid and left subclavian arteries, compared with the control group, most cases with type A AD had a significant variation.MDCT angiography plays an important role in detecting aortic arch lesions of type A AD, especially in determining the location of the intimal entry site and change of branch blood vessels. Surgeons can formulate an appropriate operating plan, according to the preoperative MDCT diagnosis information.

Evaluation and Comparison of Anatomical Landmark Detection Methods for Cephalometric X-Ray Images: A Grand Challenge.

Cephalometric analysis is an essential clinical and research tool in orthodontics for the orthodontic analysis and treatment planning. This paper presents the evaluation of the methods submitted to the Automatic Cephalometric X-Ray Landmark Detection Challenge, held at the IEEE International Symposium on Biomedical Imaging 2014 with an on-site competition. The challenge was set to explore and compare automatic landmark detection methods in application to cephalometric X-ray images. Methods were evaluated on a common database including cephalograms of 300 patients aged six to 60 years, collected from the Dental Department, Tri-Service General Hospital, Taiwan, and manually marked anatomical landmarks as the ground truth data, generated by two experienced medical doctors. Quantitative evaluation was performed to compare the results of a representative selection of current methods submitted to the challenge. Experimental results show that three methods are able to achieve detection rates greater than 80% using the 4 mm precision range, but only one method achieves a detection rate greater than 70% using the 2 mm precision range, which is the acceptable precision range in clinical practice. The study provides insights into the performance of different landmark detection approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques.

Massive enhancement of photoluminescence through nanofilm dewetting.

Due to the rather low efficiencies of conjugated polymers in solid films, their successful applications are scarce. However, recently several experiments indicated that a proper control of molecular conformations and stresses acting on the polymers may provide constructive ways to boost efficiency. Here, we report an amazingly large enhancement of photoluminescence as a consequence of strong shear forces acting on the polymer chains during nanofilm dewetting. Such sheared chains exhibited an emission probability many times higher than the nonsheared chains within a nondewetted film. This increase in emission probability was accompanied by the emergence of an additional blue-shifted emission peak, suggesting reductions in conjugation length induced by the dewetting-driven mass redistribution. Intriguingly, exciton quenching on narrow-band-gap substrates was also reduced, indicating suppression of vibronic interactions of excitons. Dewetting and related shearing processes resulting in enhanced photoluminescence efficiency are compatible with existing fabrication methods of polymer-based diodes and solar cells.