Developing red thermally activated delayed fluorescence (TADF) emitters, attainable for both high‐efficient red organic light‐emitting diodes (OLEDs) and non‐doped deep red/near‐infrared (NIR) OLEDs, ...is challenging. Now, two red emitters, BPPZ‐PXZ and mDPBPZ‐PXZ, with twisted donor–acceptor structures were designed and synthesized to study molecular design strategies of high‐efficiency red TADF emitters. BPPZ‐PXZ employs the strictest molecular restrictions to suppress energy loss and realizes red emission with a photoluminescence quantum yield (ΦPL) of 100±0.8 % and external quantum efficiency (EQE) of 25.2 % in a doped OLED. Its non‐doped OLED has an EQE of 2.5 % owing to unavoidable intermolecular π–π interactions. mDPBPZ‐PXZ releases two pyridine substituents from its fused acceptor moiety. Although mDPBPZ‐PXZ realizes a lower EQE of 21.7 % in the doped OLED, its non‐doped device shows a superior EQE of 5.2 % with a deep red/NIR emission at peak of 680 nm.
Two red emitters, BPPZ‐PXZ and mDPBPZ‐PXZ, with twisted donor–acceptor structures were designed and synthesized to study molecular design strategies of high‐efficiency red TADF emitters. BPPZ‐PXZ employs the strictest molecular restrictions to suppress energy loss and realizes red emission with a photoluminescence quantum yield (ΦPL) of 100±0.8 % and external quantum efficiency (EQE) of 25.2 % in a doped OLED.
We present an experimental demonstration of electronically tunable metamaterial absorbers in the terahertz regime. By incorporation of active liquid crystal into strategic locations within the ...metamaterial unit cell, we are able to modify the absorption by 30% at 2.62 THz, as well as tune the resonant absorption over 4% in bandwidth. Numerical full-wave simulations match well to experiments and clarify the underlying mechanism, i.e., a simultaneous tuning of both the electric and magnetic response that allows for the preservation of the resonant absorption. These results show that fundamental light interactions of surfaces can be dynamically controlled by all-electronic means and provide a path forward for realization of novel applications.
We present molecular cytogenetic characterization of del(X) (p22.33)mat and de novo dup(4) (q34.3q35.2) in a male fetus with multiple anomalies of facial dysmorphism, ventriculomegaly, congenital ...heart defects, short long bones and clinodactyly.
A 36-year-old, gravida 3, para 1, woman with short stature (152 cm) underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,Y,del(X)(p22.33)mat, dup(4)(q34.3q35.2). The mother had a karyotype of 46,X,del(X)(p22.33). Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from cultured amniocytes revealed arr Xp22.33 × 0, 4q34.3q35.2 × 3. Prenatal ultrasound at 23 weeks of gestation revealed multiple anomalies of flat nasal bridge, ventriculomegaly, atrioventricular septal defect (AVSD) and clinodactyly. The pregnancy was subsequently terminated, and a malformed fetus was delivered with facial dysmorphism. Cytogenetic analysis of the umbilical cord revealed 46,Y,del(X)(p22.33)mat, dup(4)(q34.3q35.2)dn. aCGH analysis on the DNA extracted from the umbilical cord revealed arr GRCh37 (hg19) 4q34.3q35.2 (181,149,823–188,191,938) × 3.0, arr Xp22.33 (470,485–2,985,006) × 0 with a 7.042-Mb duplication of 4q34.3-q35.2 and a 2.514-Mb deletion of Xp22.33.
A male fetus with del(X)(p22.33) and dup(4)(q34.3q35.2) may present congenital heart defects and short long bones on prenatal ultrasound.
Phase space cuts are implemented by inserting Heaviside theta functions in the integrands of momentum-space Feynman integrals. By directly parametrizing theta functions and constructing ...integration-by-parts (IBP) identities in the parametric representation, we provide a systematic method to reduce integrals with cuts. Since the IBP method is available, it becomes possible to evaluate integrals with cuts by constructing and solving differential equations.
Owing to the strong nucleophilicity of the NH2 group, free‐NH2 glycinates react with MBH acetates to usually deliver N‐allylated products even in the absence of catalysts. Without protection of the ...NH2 group, chiral pyridoxal catalysts bearing an amide side chain at the C3 position of the naphthyl ring switched the chemoselectivity of the glycinates from intrinsic N‐allylation to α‐C allylation. The reaction formed chiral multisubstituted glutamic acid esters as SN2′–SN2′ products in good yields with excellent stereoselectivity (up to 86 % yield, >20 : 1 dr, 97 % ee). As compared to pyridoxal catalysts bearing an amide side arm at the C2 position, the pyridoxals in this study have a bigger catalytic cavity to enable effective activation of larger electrophiles, such as MBH acetates and related intermediates. The reaction is proposed to proceed via a cooperative bifunctional catalysis pathway, which accounts for the high level of diastereo‐ and enantiocontrol of the pyridoxal catalysts.
A novel bifunctional chiral pyridoxal derivative 1 with a bigger catalytic cavity than that of previous pyridoxal catalysts promoted direct asymmetric α‐C allylation of NH2‐unprotected glycinates with Morita–Baylis–Hillman acetates. In this way, the chemoselectivity for glycinates was switched from intrinsic N‐allylation to α‐C allylation to produce chiral glutamic acid esters with excellent stereoselectivity (up to >20 : 1 dr and 97 % ee).
Deep learning is currently an extremely active research area in machine learning and pattern recognition society. It has gained huge successes in a broad area of applications such as speech ...recognition, computer vision, and natural language processing. With the sheer size of data available today, big data brings big opportunities and transformative potential for various sectors; on the other hand, it also presents unprecedented challenges to harnessing data and information. As the data keeps getting bigger, deep learning is coming to play a key role in providing big data predictive analytics solutions. In this paper, we provide a brief overview of deep learning, and highlight current research efforts and the challenges to big data, as well as the future trends.
Despite progress in the treatment of diabetic macular edema and diabetic retinopathy, the rate of lower fundus examination due to limitations of medical resources delays the diagnosis and treatment ...of diabetic retinopathy. Therefore, implementation of automated diabetic retinopathy screening program and the identification of more specific and sensitive biomarkers are important for facilitating the earlier detection of diabetic macular edema and diabetic retinopathy to decrease the prevalence of poor vision and blindness.
With the COVID-19 pandemic now ongoing for close to a year, people all over the world are still waiting for a vaccine to become available. The initial focus of accelerated global research and ...development efforts to bring a vaccine to market as soon as possible was on novel platform technologies that promised speed but had limited history in the clinic. In contrast, recombinant protein vaccines, with numerous examples in the clinic for many years, missed out on the early wave of investments from government and industry. Emerging data are now surfacing suggesting that recombinant protein vaccines indeed might offer an advantage or complement to the nucleic acid or viral vector vaccines that will likely reach the clinic faster. Here, we summarize the current public information on the nature and on the development status of recombinant subunit antigens and adjuvants targeting SARS-CoV-2 infections.
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•Recombinant protein vaccines constitute a proven, well-established vaccine development platform•Multiple expression systems are available to scale-up production•Various adjuvants are being used to elicit the desired immune response•Recombinant protein vaccines are suitable for production in low-resource countries•Recombinant protein COVID-19 vaccinesmay offer a better solution in the long-term
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In this paper, the reduction of Feynman integrals in the parametric representation is considered. This method proves to be more efficient than the integration-by-part (IBP) method in the ...momentum space. Tensor integrals can directly be parametrized without performing tensor reductions. The integrands of parametric integrals are functions of Lorentz scalars, instead of four momenta. The complexity of a calculation is determined by the number of propagators that are present rather than the number of all the linearly independent propagators. Furthermore, the symmetries of Feynman integrals under permutations of indices are transparent in the parametric representation. Since all the indices of the propagators are nonnegative, an algorithm to solve those identities can easily be developed, which can be used for automatic calculations.
Conjugated polymers are of great interest owing to their potential in stretchable electronics to function under complex deformation conditions. To improve the performance of conjugated polymers, ...various structural designs have been proposed and these conjugated polymers are specially applied in exotic optoelectronics. In this work, a series of all‐conjugated block copolymers (PII2T‐b‐PNDI2T) comprising poly(isoindigo–bithiophene) (PII2T) and poly(naphthalenediimide–bithiophene) (PNDI2T) are developed with varied compositions and applied to electret‐free phototransistor memory. Accordingly, these memory devices present p‐type transport capability and electrical‐ON/photo‐OFF memory behavior. The efficacy of the all‐conjugated block copolymer design in improving the memory‒photoresponse properties in phototransistor memory is revealed. By optimizing the composition of the block copolymer, the corresponding device achieves a wide memory window of 36 V and a high memory ratio of 7 × 104. Collectively, the results of this study indicate a new concept for designing electret‐free phototransistor memory by using all‐conjugated block copolymer heterojunctions to mitigate the phase separation of conjugated polymer blends. Meanwhile, the intrinsic optoelectronic properties of the constituent conjugated polymers can be well‐maintained by using an all‐conjugated block copolymer design.
A series of all‐conjugated block copolymers are developed with various compositions and applied in phototransistor memory. The electret‐free memory devices present electrical‐ON/photo‐OFF memory behavior. By optimizing the composition of block copolymer, the corresponding device achieves a high memory ratio of 7 × 104. The result represents the efficacy of the all‐conjugated block copolymer on improving the performance of phototransistor memory.
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