The effectiveness of side‐chain engineering is demonstrated to produce highly efficient all‐polymer solar cells (efficiency of 5.96%) using a series of naphthalene diimide‐based polymer acceptors ...with controlled side chains. The dramatic changes in the polymer packing, blend morphology, and electron mobility of all‐polymer solar cells elucidate clear trends in the photovoltaic performances.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
2.
Outbreak of African swine fever in South Korea, 2019 Kim, Hyun‐Joo; Cho, Ki‐Hyun; Lee, Soo‐Kyoung ...
Transboundary and emerging diseases,
March 2020, 2020-Mar, 2020-03-00, 20200301, Volume:
67, Issue:
2
Journal Article
Peer reviewed
Open access
African swine fever, a fatal haemorrhagic disease of swine, was confirmed in domestic pigs for the first time in South Korea in September 2019. The causative virus belonged to the p72 genotype II and ...had an additional tandem repeat sequence in the intergenic region (IGR) between the I73R and I329L.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
This study aimed to develop and validate deep-learning-based artificial intelligence algorithm for predicting mortality of AHF (DAHF).
12,654 dataset from 2165 patients with AHF in two hospitals were ...used as train data for DAHF development, and 4759 dataset from 4759 patients with AHF in 10 hospitals enrolled to the Korean AHF registry were used as performance test data. The endpoints were in-hospital, 12-month, and 36-month mortality. We compared the DAHF performance with the Get with the Guidelines-Heart Failure (GWTG-HF) score, Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score, and other machine-learning models by using the test data. Area under the receiver operating characteristic curve of the DAHF were 0.880 (95% confidence interval, 0.876-0.884) for predicting in-hospital mortality; these results significantly outperformed those of the GWTG-HF (0.728 0.720-0.737) and other machine-learning models. For predicting 12- and 36-month endpoints, DAHF (0.782 and 0.813) significantly outperformed MAGGIC score (0.718 and 0.729). During the 36-month follow-up, the high-risk group, defined by the DAHF, had a significantly higher mortality rate than the low-risk group(p<0.001).
DAHF predicted the in-hospital and long-term mortality of patients with AHF more accurately than the existing risk scores and other machine-learning models.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The molecular weight of a conjugated polymer is one of the key factors determining the electrical, morphological, and mechanical properties as well as its solubility in organic solvents and ...miscibility with other polymers. In this study, a series of semicrystalline poly(2,5-bis(2-hexyldecyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzoc1,2,5thiadiazole) (PPDT2FBT) polymers with different number-average molecular weights (M n’s) (PPDT2FBT L , M n = 12 kg/mol; PPDT2FBT M , M n= 24 kg/mol; PPDT2FBT H , M n= 40 kg/mol) were synthesized, and their photovoltaic properties as electron donors for all-polymer solar cells (all-PSCs) with polyN,N′-bis(2-octyldodecyl)-napthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl-alt-5,5′-(2,2′-bithiophene) (P(NDI2OD-T2)) acceptor were studied. The M n effect of PPDT2FBT on the structural, morphological, electrical, and photovoltaic properties was systematically investigated. In particular, tuning the M n induced dramatic effects on the aggregation behaviors of the polymers and their bulk heterojunction morphology of all-PSCs, which was thoroughly examined by grazing incident X-ray scattering, resonant soft X-ray scattering, and other microscopy measurements. High M n PPDT2FBT H promoted a strong “face-on” geometry in the blend film, suppressed the formation of an excessively large crystalline domain, and facilitated molecularly intermixed phases with P(NDI2OD-T2). Therefore, the optimized all-PSCs based on PPDT2FBT H /P(NDI2OD-T2) showed substantially higher hole and electron mobilities than those of PPDT2FBT L /P(NDI2OD-T2), leading to a power conversion efficiency exceeding 5%, which is one of the highest values for all-PSCs reported thus far.
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Remarkable progress has been realized in improving the power conversion efficiency (PCE) of polymer solar cells (PSCs) over the past few years, raising the possibility of their commercialization as ...an alternative counterpart to conventional inorganic solar cells. The development of conjugated polymers that contain various alternately bonded electron-rich (D) and electron-deficient (A) units, called D-A alternating copolymers, plays a crucial role in improving the PCE of PSCs, which has now exceeded 8-9%. However, further development of conjugated polymers is essential to produce highly efficient and stable PSCs with a PCE of more than 10% for commercialization. In this regard, terpolymers, which consist of three different units in the polymer backbone, are promising candidates because they can show synergetic effects of each unit by tuning the composition ratio, thereby enabling full-range absorption, high charge mobility, and good solubility. Substantial progress in the development of terpolymers has been achieved with regard to PCE. Herein, we review the development of terpolymers for PSCs and discuss the major factors that need to be considered in the design of new terpolymers.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pneumonia emerged in Wuhan, China in December 2019. In this retrospective multicenter study, we investigated the clinical course ...and outcomes of novel coronavirus disease 2019 (COVID-19) from early cases in Republic of Korea.
All of the cases confirmed by real time polymerase chain reaction were enrolled from the 1st to the 28th patient nationwide. Clinical data were collected and analyzed for changes in clinical severity including laboratory, radiological, and virologic dynamics during the progression of illness.
The median age was 40 years (range, 20-73 years) and 15 (53.6%) patients were male. The most common symptoms were cough (28.6%) and sore throat (28.6%), followed by fever (25.0%). Diarrhea was not common (10.7%). Two patients had no symptoms. Initial chest X-ray (CXR) showed infiltration in 46.4% of the patients, but computed tomography scan confirmed pneumonia in 88.9% (16/18) of the patients. Six patients (21.4%) required supplemental oxygen therapy, but no one needed mechanical ventilation. Lymphopenia was more common in severe cases. Higher level of C-reactive protein and worsening of chest radiographic score was observed during the 5-7 day period after symptom onset. Viral shedding was high from day 1 of illness, especially from the upper respiratory tract (URT).
The prodromal symptoms of COVID-19 were mild and most patients did not have limitations of daily activity. Viral shedding from URT was high from the prodromal phase. Radiological pneumonia was common from the early days of illness, but it was frequently not evident in simple CXR. These findings could be plausible explanations for the easy and rapid spread of SARS-CoV-2 in the community.
A new series of conjugated random terpolymers (PDPP2T-Se-Th) was synthesized from an electron-deficient diketopyrrolopyrrole (DPP)-based unit in conjugation with two electron-rich selenophene (Se) ...and thiophene (Th) species, with a view to inducing different crystalline behaviors of the polymers. The crystallinity of the polymers can be systematically controlled by tuning the ratio between Se and Th; an increase in Se content induced a remarkable increase in the melting and crystallization temperatures as well as the crystallinity of the PDPP2T-Se-Th terpolymers. These changes in the crystalline properties of polymers had a dramatic effect on the performances of organic field-effect transistors (OFETs) and polymer solar cells (PSCs). However, their effect on each type of devices was very different. The charge carrier mobilities of the PDPP2T-Se-Th terpolymers in OFET devices increased remarkably as the Se content increased in the polymers, showing that PDPP2T-Se100 with Se/Th ratio = 100/0 had very high hole and electron mobilities (4.72 and 5.54 cm2 V–1 s–1, respectively) with well-balanced ambipolar property. In contrast, the best power conversion efficiency (PCE) of 7.2% was observed for the PDPP2T-Se10-Th90 polymers that had Se/Th ratio of 10/90 due to the synergistic contributions from high charge mobility and optimized bulk-heterojunction (BHJ) morphology with fullerene acceptors. To understand the effects of the crystallinity of random terpolymers on their performances in OTFTs and PSCs, we systematically investigated the effects of the Se/Th compositions on their optical, electrical, and structural properties.
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A novel framework of azide containing photo‐crosslinkable, conducting copolymer, that is, poly(azido‐styrene)‐random‐poly(triphenylamine) (X‐PTPA), is reported as a hole‐transporting material for ...efficient solution‐processed, multi‐layer, organic light emitting diodes (OLEDs). A facile and energy‐efficient crosslinking process is demonstrated with UV irradiation (254 nm, 2 mW/cm2) at a short exposure time (5 min). By careful design of X‐PTPA, in which 5 mol% of the photo‐crosslinkable poly(azido‐styrene) is copolymerized with hole‐transporting poly(triphenylamine) (X‐PTPA‐5), the adverse effect of the crosslinking of azide moieties is prevented to maximize the performances of X‐PTPA‐5. Since the photo‐crosslinking chemistry of azide molecules does not involve any photo‐initiators, superior hole‐transporting ability is achieved, producing efficient devices. To evaluate the performances of X‐PTPA‐5 as a hole‐transporting/electron‐blocking layer, Ir(ppy)3‐based, solution‐processable OLEDs are fabricated. The results show high EQE (11.8%), luminous efficiency (43.7 cd/A), and power efficiency (10.4 lm/W), which represent about twofold enhancement over the control device without X‐PTPA‐5 film. Furthermore, micro‐patterned OLEDs with the photo‐crosslinkable X‐PTPA‐5 can be fabricated through standard photolithography. The versatility of this approach is also demonstrated by introducing the same azide moiety into other hole‐transporting materials such as poly(carbazole) (X‐PBC).
Photo‐crosslinkable azide (N3) containing X‐PTPA is used as a HTL/EBL layer for highly efficient, solution‐processed multi‐layer OLEDs. The X‐PTPA with 5 mol% of N3 group can be fully crosslinked via mild UV irradiation at short exposure time. A twofold enhancement of device performance is realized with X‐PTPA layer over the control device. This photo‐crosslinkable HTL/EBL layer also allows the fabrication of micro‐pixelated multi‐layer OLEDs by photolithography.
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MXene is an emerging class of two-dimensional nanomaterials with exceptional electroconductivity and electrochemical properties, and is promising in the manufacturing of multifunctional ...macroscopic materials and nanomaterials. Herein, we develop a straightforward, continuously controlled, additive/binder-free method to fabricate pure MXene fibers via a large-scale wet-spinning assembly. Our MXene sheets (with an average lateral size of 5.11 μm
) are highly concentrated in water and do not form aggregates or undergo phase separation. Introducing ammonium ions during the coagulation process successfully assembles MXene sheets into flexible, meter-long fibers with very high electrical conductivity (7,713 S cm
). The fabricated MXene fibers are comprehensively integrated by using them in electrical wires to switch on a light-emitting diode light and transmit electrical signals to earphones to demonstrate their application in electrical devices. Our wet-spinning strategy provides an approach for continuous mass production of MXene fibers for high-performance, next-generation, and wearable electronic devices.
This study examines how and when top management's environmental support influences firms' environmental performance and investigates a moderated mediating role of external supplier factors in ...environmental management practices. A multinational data set collected from 289 manufacturing companies was used to examine the proposed hypotheses empirically. The results demonstrate that top management environmental support promotes environmental performance directly but also indirectly through supplier environmental management. Besides, the results show that supplier adaptability strengthens the indirect effect of top management environmental support on environmental performance via supplier environmental management. By combining external supplier factors with internal top-management environmental support, this research contributes to a better understanding of how to promote environmental performance more effectively.
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