Insights into supermassive black hole mergers from the gravitational wave background
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Surfactant-induced hole concentration enhancement for highly efficient perovskite light-emitting diodes
It is widely acknowledged that constructing small injection barriers for balanced electron and hole injections is essential for light-emitting diodes (LEDs). However, in highly efficient LEDs based on metal halide perovskites, a seemingly large hole injection barrier is usually observed. Here we rationalize this high efficiency through a surfactant-induced effect where the hole concentration at the perovskite surface is enhanced to enable sufficient bimolecular recombination pathways with injected electrons. This effect originates from the additive engineering and is verified by a series of optical and electrical measurements. In addition, surfactant additives that induce an increased hole concentration also significantly improve the luminescence yield, an important parameter for the efficient operation of perovskite LEDs. Our results not only provide rational design rules to fabricate high-efficiency perovskite LEDs but also present new insights to benefit the design of other perovskite optoelectronic devices.
The WAVE complex in developmental and adulthood brain disorders
Actin polymerization and depolymerization are fundamental cellular processes required not only for the embryonic and postnatal development of the brain but also for the maintenance of neuronal plasticity and survival in the adult and aging brain. The orchestrated organization of actin filaments is controlled by various actin regulatory proteins. Wiskott‒Aldrich syndrome protein-family verprolin-homologous protein (WAVE) members are key activators of ARP2/3 complex-mediated actin polymerization. WAVE proteins exist as heteropentameric complexes together with regulatory proteins, including CYFIP, NCKAP, ABI and BRK1. The activity of the WAVE complex is tightly regulated by extracellular cues and intracellular signaling to execute its roles in specific intracellular events in brain cells. Notably, dysregulation of the WAVE complex and WAVE complex-mediated cellular processes confers vulnerability to a variety of brain disorders. De novo mutations in WAVE genes and other components of the WAVE complex have been identified in patients with developmental disorders such as intellectual disability, epileptic seizures, schizophrenia, and/or autism spectrum disorder. In addition, alterations in the WAVE complex are implicated in the pathophysiology of Alzheimer’s disease and Parkinson’s disease, as well as in behavioral adaptations to psychostimulants or maladaptive feeding.
Achievement of a vacuum-levitated metal mechanical oscillator with ultra-low damping rate at room temperature
A vacuum-levitated metal mechanical oscillator with an ultra-low damping rate is an ideal tool for detecting mass-related short-range forces; however, its realization at room temperature has not yet been achieved, limiting its practical applications. In this study, we developed such an oscillator using a diamagnetically levitated bismuth sphere. We derived an accurate general formula for the sphere’s eddy current damping rate and, based on this, constructed the oscillator from microparticles, successfully reducing its damping rate experimentally to (144 ± 6) μHz—nearly three orders of magnitude lower than that of the untreated sphere. This improvement allows the sub-millimeter-sized levitated metal mechanical oscillator to theoretically achieve a force sensitivity of ((5.17pm 0.12),,{mbox{fN}}/sqrt{{mbox{Hz}},}) and an acceleration sensitivity of ((0.30pm 0.01),,{mbox{ng}}/sqrt{{mbox{Hz}},}) at room temperature. Calculations indicate that using this sphere as a test mass can detect gravitational forces from sub-milligram sources, highlighting its potential for short-range force sensing and the exploration of quantum gravity.
Well-being horizons for silver and golden ages: an application of traditional and fuzzy Markov chains
European societies are currently in a process of population ageing. Although this is the general trend, it would be desirable to know whether the characteristics and intensity of this ageing process are homogeneous in all European countries. In this work, information coming from three macro-surveys (or waves) of the Survey on Health Ageing and Retirement in Europe is used for Denmark, Germany, Poland and Spain, as the basis for a longitudinal well-being and dependency indicator with the aim of studying whether the characteristics of ageing are similar in these regions. First, long-term population distributions are obtained according to the scores of the aforementioned indicator. Next, classical and fuzzy Markov chains are used to estimate steady-state distributions regarding age group, gender, country and wave. Finally, by means of a proper metric for probability distributions, steady-state distributions are clustered in different profiles, which leads us to conclude that the ageing process is not homogeneous among the studied populations.
Universal conservation laws of the wave-particle-entanglement triad: theory and experiment
When observed, a quantum system exhibits either wave-like or particle-like properties, depending on how it is measured. However, this duality is affected by the entanglement of the system with its quantum memory, raising a fundamental question: how are wave–particle duality and entanglement related? Here, we broaden the scope of wave–particle duality to include entanglement, introduce universal conservation laws for the wave–particle–entanglement triad, and perform demonstrations on silicon–integrated nanophotonic quantum chips. Our experiments not only mark the first confirmation of universal conservation laws but also highlight the potential of integrated photonics for exploring complex quantum phenomena in high-dimensional systems.
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