This study reports a new nonfullerene electron transporting material (ETM) based on naphthalene diimide (NDI) small molecules for use in high‐performance perovskite solar cells (PSCs). These solar ...cells simultaneously achieve high power conversion efficiency (PCE) of over 20% and long‐term stability. New NDI‐ID (N,N′‐Bis(1‐indanyl)naphthalene‐1,4,5,8‐tetracarboxylic diimide) consisting of an N‐substituted indane group having simultaneous alicyclic and aromatic characteristics is synthesized by a low‐cost, one‐step reaction, and facile purification method. The partially flexible characteristics of an alicyclic cyclopentene group on indane groups open the possibility of low‐temperature solution processing. The conformational rigidity and aromaticity of phenyl and alicyclic groups contribute to high temporal stability by strong secondary bonds. NDI‐ID has herringbone packed semiconducting NDI cores that exhibit up to 0.2 cm2 V−1 s−1 electron mobility in field effect transistors. The inverted PSCs based on CH(NH2)2PbI3–xBrx with NDI‐ID ETM exhibit very high PCEs of up to 20.2%, which is better than that of widely used PCBM (phenyl‐C61‐butyric acid methyl ester) ETM‐based PSCs. Moreover, NDI‐ID‐based PSCs exhibit very high long‐term temporal stability, retaining 90% of the initial PCE after 500 h at 100 °C with 1 sun illumination without encapsulation. Therefore, NDI‐ID is a promising ETM for highly efficient, stable PSCs.
A new nonfullerene electron transporting material based on naphthalene diimide with indane groups having simultaneous alicyclic and aromatic characteristics is developed for low‐temperature solution‐processable perovskite solar cells, and it shows up to 20.2% power conversion efficiency and long‐term temporal stability.
Antimicrobial peptides (AMPs) are promising therapeutic agents for treating antibiotic-resistant bacterial infections. Previous studies showed that magainin 2 (isolated from African clawed fogs
) has ...antimicrobial activity against gram-positive and gram-negative bacteria. The present study was conducted to investigate the antibacterial activity of magainin 2 against
. Magainin 2 showed excellent antibacterial activity against
strains and high stability at physiological salt concentrations. This peptide was not cytotoxic towards HaCaT cells and showed no hemolytic activity. Biofilm inhibition and elimination were significantly induced in all
strains exposed to magainin 2. We confirmed the mechanism of magainin 2 on the bacterial outer and inner membranes. Collectively, these results suggest that magainin 2 is an effective antimicrobial and antibiofilm agent against
strains.
The risks and benefits of long-term dual antiplatelet therapy remain unclear.
This prospective, multicenter, open-label, randomized comparison trial was conducted in 24 clinical centers in Korea. In ...total, 5045 patients who received drug-eluting stents and were free of major adverse cardiovascular events and major bleeding for at least 12 months after stent placement were enrolled between July 2007 and July 2011. Patients were randomized to receive aspirin alone (n=2514) or clopidogrel plus aspirin (n=2531). The primary end point was a composite of death resulting from cardiac causes, myocardial infarction, or stroke 24 months after randomization. At 24 months, the primary end point occurred in 57 aspirin-alone group patients (2.4%) and 61 dual-therapy group patients (2.6%; hazard ratio, 0.94; 95% confidence interval, 0.66-1.35; P=0.75). The 2 groups did not differ significantly in terms of the individual risks of death resulting from any cause, myocardial infarction, stent thrombosis, or stroke. Major bleeding occurred in 24 (1.1%) and 34 (1.4%) of the aspirin-alone group and dual-therapy group patients, respectively (hazard ratio, 0.71; 95% confidence interval, 0.42-1.20; P=0.20).
Among patients who were on 12-month dual antiplatelet therapy without complications, an additional 24 months of dual antiplatelet therapy versus aspirin alone did not reduce the risk of the composite end point of death from cardiac causes, myocardial infarction, or stroke.
http://www.clinicaltrials.gov. Unique identifier: NCT01186146.
Patients with unprotected left main coronary artery stenosis were assigned to either CABG or PCI with sirolimus-eluting stents. At 1 year, with a wide prespecified noninferiority margin, PCI was ...found to be noninferior to CABG.
Anumber of registry reports, as well as a substudy from a large, randomized trial, have indicated that percutaneous coronary intervention (PCI) may be an acceptable alternative to coronary-artery bypass grafting (CABG) in some patients with unprotected left main coronary artery stenosis.
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Recent clinical guidelines have accordingly stated that elective PCI can be considered for patients who have unprotected left main coronary artery disease, although they suggest that the aggregated evidence favors CABG.
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Whether the outcomes after PCI are similar to those after CABG remains uncertain, however, owing to the lack of large, randomized clinical trials. Registry results have . . .
Patients with multivessel coronary artery disease were randomly assigned to PCI with everolimus-eluting stents or CABG. At 2 years, the composite of death, myocardial infarction, or target-vessel ...revascularization occurred more frequently in the PCI group.
Randomized trials and observational studies have shown that the rates of most adverse clinical outcomes among patients with multivessel coronary artery disease are lower after coronary-artery bypass grafting (CABG) than after percutaneous coronary intervention (PCI).
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Current clinical guidelines thus recommend CABG as the preferred revascularization strategy, particularly in patients with complex coronary lesions and without excessive operative risk.
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However, previous trials may have been limited by their use of first-generation drug-eluting stents. Although these stents reduced the rate of restenosis, their use was associated with a relatively high rate of stent-related thrombotic events.
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Results from the Synergy between . . .
Biomolecular piezoelectric materials are considered a strong candidate material for biomedical applications due to their robust piezoelectricity, biocompatibility, and low dielectric property. The ...electric field has been found to affect tissue development and regeneration, and the piezoelectric properties of biological materials in the human body are known to provide electric fields by pressure. Therefore, great attention has been paid to the understanding of piezoelectricity in biological tissues and its building blocks. The aim herein is to describe the principle of piezoelectricity in biological materials from the very basic building blocks (i.e., amino acids, peptides, proteins, etc.) to highly organized tissues (i.e., bones, skin, etc.). Research progress on the piezoelectricity within various biological materials is summarized, including amino acids, peptides, proteins, and tissues. The mechanisms and origin of piezoelectricity within various biological materials are also covered.
The piezoelectricity of the various elements constituting the human body has attracted intensive attention, due to the strong piezoelectricity, biocompatibility, low dielectric, and tissue regeneration effects. Research progress in the various biological piezoelectric materials from the basic building blocks to organized tissues are summarized. The mechanisms and origins of piezoelectricity are discussed, and challenges and perspectives for developing biological piezoelectric materials are presented.
Asymptomatic patients with very severe aortic stenosis were randomly assigned to either early valve-replacement surgery or conservative care. At a median of 6 years of follow-up, the composite of ...operative mortality or death from cardiovascular causes occurred less frequently in the early-surgery group.
Metal halide perovskites are attracting a lot of attention as next-generation light-emitting materials owing to their excellent emission properties, with narrow band emission
. However, perovskite ...light-emitting diodes (PeLEDs), irrespective of their material type (polycrystals or nanocrystals), have not realized high luminance, high efficiency and long lifetime simultaneously, as they are influenced by intrinsic limitations related to the trade-off of properties between charge transport and confinement in each type of perovskite material
. Here, we report an ultra-bright, efficient and stable PeLED made of core/shell perovskite nanocrystals with a size of approximately 10 nm, obtained using a simple in situ reaction of benzylphosphonic acid (BPA) additive with three-dimensional (3D) polycrystalline perovskite films, without separate synthesis processes. During the reaction, large 3D crystals are split into nanocrystals and the BPA surrounds the nanocrystals, achieving strong carrier confinement. The BPA shell passivates the undercoordinated lead atoms by forming covalent bonds, and thereby greatly reduces the trap density while maintaining good charge-transport properties for the 3D perovskites. We demonstrate simultaneously efficient, bright and stable PeLEDs that have a maximum brightness of approximately 470,000 cd m
, maximum external quantum efficiency of 28.9% (average = 25.2 ± 1.6% over 40 devices), maximum current efficiency of 151 cd A
and half-lifetime of 520 h at 1,000 cd m
(estimated half-lifetime >30,000 h at 100 cd m
). Our work sheds light on the possibility that PeLEDs can be commercialized in the future display industry.
Brain organoids derived from human pluripotent stem cells provide a highly valuable in vitro model to recapitulate human brain development and neurological diseases. However, the current systems for ...brain organoid culture require further improvement for the reliable production of high-quality organoids. Here, we demonstrate two engineering elements to improve human brain organoid culture, (1) a human brain extracellular matrix to provide brain-specific cues and (2) a microfluidic device with periodic flow to improve the survival and reduce the variability of organoids. A three-dimensional culture modified with brain extracellular matrix significantly enhanced neurogenesis in developing brain organoids from human induced pluripotent stem cells. Cortical layer development, volumetric augmentation, and electrophysiological function of human brain organoids were further improved in a reproducible manner by dynamic culture in microfluidic chamber devices. Our engineering concept of reconstituting brain-mimetic microenvironments facilitates the development of a reliable culture platform for brain organoids, enabling effective modeling and drug development for human brain diseases.
Magnetic torques generated through spin-orbit coupling
promise energy-efficient spintronic devices. For applications, it is important that these torques switch films with perpendicular magnetizations ...without an external magnetic field
. One suggested approach
to enable such switching uses magnetic trilayers in which the torque on the top magnetic layer can be manipulated by changing the magnetization of the bottom layer. Spin currents generated in the bottom magnetic layer or its interfaces transit the spacer layer and exert a torque on the top magnetization. Here we demonstrate field-free switching in such structures and show that its dependence on the bottom-layer magnetization is not consistent with the anticipated bulk effects
. We describe a mechanism for spin-current generation
at the interface between the bottom layer and the spacer layer, which gives torques that are consistent with the measured magnetization dependence. This other-layer-generated spin-orbit torque is relevant to energy-efficient control of spintronic devices.
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