The realization of luminescent materials with narrowband and circularly polarized luminescence (CPL) is of great significance for the development of future optical and photonic devices. Herein, ...through a steric‐hindrance‐assisted dual‐core strategy, two pairs of chiral dual‐core multiple resonance thermally activated delayed fluorescence (MR‐TADF) materials (R/S‐DOBN and R/S‐DOBNT) are directly constructed by the bonding of two organoboron MR‐TADF monocores (SOBN and SOBNT) with carbazole/3,6‐di‐tert‐butyl‐9H‐carbazole and phenol derivative as donors, realizing obvious CPL and narrowband emissions. Furthermore, the dual‐core effect in the prepared R/S‐DOBN and R/S‐DOBNT increases the transition oscillator strength two times more than that of a monocore structure, while maintaining the ultrapure blue emissions peaking at 453 and 459 nm with a narrower full‐width at half‐maximum of 21 nm through reorganization energy reduction. The circularly polarized organic light‐emitting diodes based on the enantiomers exhibit ultrapure blue emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.14, 0.10) and (0.13, 0.12), high maximum external quantum efficiencies of 23.9% and 25.6%, and obvious circularly polarized electroluminescence with dissymmetry factors (|gEL|) ≈ 10−3.
Through a steric‐hindrance‐assisted dual‐core strategy, chiral organoboron structures are prepared by direct bonding of two multiple‐resonance thermally activated delayed fluorescence (MR‐TADF) monocores, realizing superior chiroptical property and dual‐channel enhanced ultrapure blue emission. Furthermore, highly efficient circularly polarized organic light‐emitting diodes (CP‐OLEDs) with maximum external quantum efficiencies of 23.9% and 25.6% are achieved.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Bromodifluoromethylphosphonium bromide was solely used as the precursor of difluorocarbene. Herein, an unprecedented visible‐light‐induced hydrodifluoromethylation of alkenes with ...bromodifluoromethylphosphonium bromide using H2O and THF as hydrogen sources for the synthesis of difluoromethylated alkanes is described. This difluoromethylation is characterized by mild reaction conditions, ready availability of reagents, and excellent functional‐group tolerance.
Getting involved: The visible‐light photoredox catalysis of alkenes with a bromodifluoromethylphosphonium bromide using H2O and THF as hydrogen sources afforded hydrodifluoromethylated alkanes in moderate to excellent yields. The in situ generated difluoromethylphosphonium salt and a CF2H radical are involved in this transformation. ppy=2‐phenylpyridine.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this work, we have developed an electrochemical aptasensor for high-sensitivity determination of carcinoembryonic antigen (CEA) based on lead ion (Pb2+)-dependent DNAzyme-assisted signal ...amplification and graphene quantum dot-ionic liquid-nafion (GQDs-IL-NF) composite film. We designed hairpin DNA containing CEA-specific aptamers and DNAzyme chains. In the presence of CEA, hairpin DNA recognized the target and performed a DNAzyme-assisted signal amplification reaction to yield a large number of single-stranded DNA. The GQDs-IL-NF composite film was immobilized on the glassy carbon electrode for the interaction with single-stranded DNA through noncovalent π-π stacking interaction. Therefore, the methylene blue-labeled substrate DNA (MB-substrate) was fixed on the electrode and exhibited an initial electrochemical signal. Under optimal conditions, the response current change was proportional to the concentration of CEA, demonstrating a wide linear range from 0.5fgmL−1 to 0.5ngmL−1, with a low detection limit of 0.34fgmL−1. Furthermore, the proposed aptasensor was successfully applied in determining CEA in serum samples, showing its superior prospects in clinical diagnosis.
•Pb2+dependent DNAzyme electrochemical biosensor for carcinoembryonic antigen detection was developed.•The graphene quantum dots-ionic liquid-nafion composite film was fabricated on electrode for the first time.•The target-aptamer complex recycling led to continuous cleavage of substrate chain and amplified electrochemical signal.•The method has been applied in human serum, with high selectivity and good recovery.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Aim
The purpose of this study was to explore the effect of a preoperative nutritional support programme on improving preoperative nutritional status and promoting postoperative recovery in neonates ...undergoing cardiac surgery.
Methods
The clinical data of neonates undergoing cardiac surgery who received preoperative nutritional support therapy in our hospital from March 2021 to December 2021 were collected, and the clinical data of neonates undergoing cardiac surgery who did not receive preoperative nutritional support therapy in our hospital from February 2020 to February 2021 were selected as the control. The nutritional status and postoperative recovery of the two groups were compared.
Results
A total of 30 neonates who received nutritional support before cardiac surgery were included in this study. A total of 28 neonates who did not receive nutritional support before cardiac surgery were included in the control group. There were no significant differences in general information or the nutritional status at birth between the two groups. The duration of nutritional support in the intervention group was 16.8 ± 7.1 days. Before the operation, the intervention group was significantly better than the control group in terms of body weight, albumin, prealbumin and haemoglobin, which indicated that the nutritional status of the intervention group was better than that of the control group. The intensive care time, ventilator time and hospital stay time in the intervention group were significantly lower than those in the control group.
Conclusion
Nutritional support plans after birth for neonates with severe congenital heart disease can effectively improve the nutritional status of patients before surgery and accelerate the speed of postoperative recovery.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Switchable nonlinear optical (NLO) materials have aroused broad interest on account of their captivating optical and electronic properties. We demonstrate a novel perovskite-type crystal with ...exceptional hydrogen bond interactions that are associated with the onset of reorientational motions of organic cations and thus induce the occurrence of two successive phase transitions to be a two-step NLO switch. This finding affords an alternative approach for the design and assembly of switchable NLO materials.
A tunable chemoselective trifluoromethanesulfonylation and trifluoromethylation of arenediazonium tetrafluoroborates with Langlois' reagent (NaSO2CF3) was developed. The Cu2O-catalyzed reaction in ...DMSO gave aryl trifluoromethanesulfones as the major products. On the other hand, the trifluoromethylated arenes were produced in the presence of oxidant tert-butyl hydroperoxide, CuBF4(MeCN)4, and 2,2';6',2″-terpyridine (tpy). Both of these transformations proceed under mild conditions and tolerate functional groups.
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IJS, KILJ, NUK, PNG, UL, UM
This paper made analysis on the topic of Low-voltage network that contacts parallel resonance system with cable. A new method in detecting insulation parameters was presented through added testing ...resistance in single phase. The corresponding circuit model is established and the theory is proved that there is linearity among resonance capacitance, inductance and insulated resistance. Simulation study was carried out in this paper. The research shows: the testing error of this insulation detection method is within±0.5% which has high accuracy.
Tea, as one of the most popular beverages with various bioactivities, is commonly produced from the fresh leaves of two widely cultivated tea plants, Camellia sinensis and C. sinensis var. assamica. ...Both plants belong to the genus Camellia section Thea, which was considered to have 12 species and 6 varieties according to Min’s taxonomic system. Most species, except the cultivated species, are known as wild tea plants and have been exploited and utilized to produce tea by the local people of its growing areas. Thus far, six species and varieties have been phytochemically studied, leading to the identification of 398 compounds, including hydrolyzable tannins, flavan-3-ols, flavonoids, terpenoids, alkaloids, and other phenolic and related compounds. Various beneficial health effects were reported for tea and its components, involving antioxidant, antitumor, antimutagenic, antidiabetic, hypolipidemic, anti-inflammatory, antimicrobial, antiviral, antifungal, neuroprotective, hepatoprotective, etc. In this review, the geographical distribution of tea plants and the chemical constituents (1–398) reported from the genus Camellia section Thea and some tea products (green, black, oolong, and pu-erh tea) that have ever been studied between 1970 and 2018 have been summarized, taking species as the main hint, and the main biological activities are also discussed.
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Organic–inorganic hybrid perovskite materials have attracted much attention because they combine the advantages of the organic and inorganic components at the molecular level. Organic–inorganic ...hybrid materials have both the structural variability and the flexibility of organic components, as well as magnetic, electrical, and thermal properties of inorganic components. A novel one-dimensional organic–inorganic hybrid halide perovskite material Et3NCH2BrPbBr3 (compound 1) undergoes a high-temperature phase transition at around 429.3 K, which is triggered by the order–disorder change of cations. Differential scanning calorimetry, a dielectric test, and single-crystal X-ray diffraction indicate that compound 1 exhibits structural phase transition from the P21/c to P63/m space group and a prominent dielectric anomaly. Strikingly, the bandgap of compound 1 is 3.12 eV. It is believed that our findings will contribute to an alternative pathway for the design of multifunctional materials.
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Ceramic dielectric capacitors have attracted increasing interest due to their wide applications in pulsed power electronic systems. Nevertheless, synchronously achieving the high energy storage ...density, high energy storage efficiency and good thermal stability in dielectric ceramics is still a great challenge. Herein, lead free Sr
3
SmNa
2
Fe
0.5
Nb
9.5
O
30
(SSNFN) ceramic with tetragonal tungsten bronze structure was synthesized and characterized, high total energy storage density (2.1 J cm
−3
), recoverable energy storage density (1.7 J cm
−3
), energy storage efficiency (80%) and good thermal stability are obtained simultaneously in the compound, due to the contribution of high maximum polarization (
P
max
), low remanent polarization (
P
r
) and large breakdown strength (
E
b
). The high
P
max
is related with the intrinsic characteristic of Sr
4
Na
2
Nb
10
O
30
(SNN) based system, while the small
P
r
and good thermal stability stem from the significantly enhanced relaxor behavior. In addition, the large
E
b
originates from the improved microstructure with fewer defects and decreased average grain size, and the reduction of electrical heterogeneity compared with SNN. The capacitive performance obtained in this work points out the great potential of tungsten bronze ceramic designed for energy storage applications and pave a feasible way to develop novel lead-free dielectric capacitors.
Lead free Sr
3
SmNa
2
Fe
0.5
Nb
9.5
O
30
ceramic was synthesized and characterized, and high total energy storage density, recoverable energy storage density, energy storage efficiency and good thermal stability are synchronously achieved.
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