Non‐linear optical chalcogenides with a wide band gap (Eg) and excellent NLO properties are key materials for highly desirable multiwaveband tunable optical parametric oscillators (OPOs). We exploit ...the “electronic structure engineer bucket effect” to develop a novel dual‐waveband SrZnGeS4 with an ultrawide transparency window. It exhibits an asymmetric Fdd2 structure that consists of layers formed by corner‐sharing ZnGeS6 dimers. SrZnGeS4 is transparent from 0.30 to 23.6 μm, spanning the UV‐, vis‐, mid‐ and far‐IR spectral regions and has the widest Eg (3.63 eV) in the AeMIIMIVQ4 family to date. It exhibits phase matching, high SHG intensities (e.g., 11.0×KDP and 17.5×AGS under λinc=1450 and 950 nm, respectively), and a very high laser‐induced damage threshold (35×AGS). These results not only suggest bright prospects for high‐power laser applications but may also enable applications of the multiwaveband OPO system from the UV‐visible to far‐IR regions.
An electronic structure‐engineering “bucket effect” strategy produces a novel non‐linear optical compound SrZnGeS4 with unique dual‐waveband NLO properties, including a second harmonic generation of 0.9–17.5×AgGaS2 under 850–2100 nm incident laser wavelengths and a laser‐induced damage threshold of 35×AgGaS2.
Currently, tRNA-derived small RNAs (tsRNAs) are recognized as a novel and potential type of non-coding RNAs (ncRNAs), which participate in various cellular processes and play an essential role in ...cancer progression. However, tsRNAs involvement in colorectal cancer (CRC) progression remains unclear.
Sequencing analyses were performed to explore the tsRNAs with differential expression in CRC. Gain- and loss-of functions of 5'tiRNA-His-GTG were performed in CRC cells and xenograft tumor to discover its role in the progression of CRC. Hypoxia culture and hypoxia inducible factor 1 subunit alpha (HIF1α) inhibitors were performed to uncover the biogenesis of 5'tiRNA-His-GTG. The regulation of 5'tiRNA-His-GTG for large tumor suppressor kinase 2 (LATS2) were identified by luciferase reporter assay, western blot, and rescue experiments.
Here, our study uncovered the profile of tsRNAs in human CRC tissues and confirmed a specific tRNA half, 5'tiRNA-His-GTG, is upregulated in CRC tissues. Then, in vitro and in vivo experiments revealed the oncogenic role of 5'tiRNA-His-GTG in CRC and found that targeting 5'tiRNA-His-GTG can induce cell apoptosis. Mechanistically, the generation of 5'tiRNA-His-GTG seems to be a responsive process of tumor hypoxic microenvironment, and it is regulated via the HIF1α/angiogenin (ANG) axis. Remarkably, LATS2 was found to be an important and major target of 5'tiRNA-His-GTG, which renders 5'tiRNA-His-GTG to "turn off" hippo signaling pathway and finally promotes the expression of pro-proliferation and anti-apoptosis related genes.
In summary, the findings revealed a specific 5'tiRNA-His-GTG-engaged pathway in CRC progression and provided clues to design a novel therapeutic target in CRC.
The strong mutual coupling of and even the opposite change in the key parameters, such as the band gap (Eg) and second‐order harmonic generation (SHG), leads to the extreme scarcity in ...high‐performance IR nonlinear optical (NLO) chalcogenides. Herein, we report 8 new sulfides, Na2Ba(AgxNa1−x)2Sn2S7 (1, x=0; 1 series, x=0.1–0.6; Na2Ba(Li0.58Na0.42)2Sn2S7, 1‐0.6Li); Na2SrCu2Sn2S7 (2); and Na2BaCu2Sn2S7 (3). We use the structural tolerance factor (
tIexp
${{t}_{I}^{exp}}$
) to connect the chemical composition, crystal structure, and NLO properties. Guided by these correlations, a better balance between Eg and SHG is realized in 1, which exhibits a large Eg of 3.42 eV and excellent NLO properties (SHG: 1.5×AGS; laser‐induced damage threshold: 12×AGS), representing the best performance among the known Hg‐ or As‐free sulfides to date.
Guided by the relationships between the structural tolerance factor and the dopant concentration and second‐order susceptibility, a better balance between Eg and SHG is realized in Na2Ba Na2Sn2S7 1, which exhibits a large Eg of 3.42 eV and excellent NLO properties (SHG: 1.5×AGS; laser‐induced damage threshold: 12×AGS), representing the best performance among the known Hg‐ or As‐free sulfides to date.
In this paper, a high-performance torque control scheme of an interior permanent magnet synchronous machine (IPMSM) is introduced, which focuses on both steady state and transient torque dynamics of ...the IPMSM under the maximum torque per ampere (MTPA) condition. For the proposed control scheme with model-based torque correction, an accurate and efficient torque control with robust torque response can be achieved for the MPTA operation. Global stability and performance of the proposed torque control scheme are theoretically guaranteed. The current limitation of the IPMSM is easily handled without anti-windup and without degrading the torque dynamics or stability even the torque demand is beyond the maximum reachable torque. Implementation issues of the proposed control scheme to the real IPMSM plant with parameter variation are discussed. With the compensation of the linear and nonlinear inverter voltage drop, a robust and accurate torque response for the real-time MTPA operation can be achieved by an adaptive current control and online parameter estimation. The simulation and experimental results validate the safety and high performance of the proposed torque control scheme.
•A general solution is presented for RUL prediction of nonlinear deterioration process.•KPCA is selected for dimensionality reduction and nonlinear feature extraction.•GRU is presented to replace ...LSTM, which behaves better both in prediction accuracy and training time.
Remaining useful life (RUL) prediction is a key process for prognostics and health management (PHM). However, conventional model-based methods and data-driven methods for RUL prediction are bad at a very complex system with multiple components, multiple states and therefore extremely large amount of parameters. In order to solve the problem, a general two-step solution is proposed in this paper. In the first step, kernel principle component analysis (KPCA) is applied for nonlinear feature extraction. Then, a novel recurrent neural network called gated recurrent unit (GRU) is presented as the second step to predict RUL. GRU network is capable of describing a very complex system because of its specially designed structure. The effectiveness of the proposed solution for RUL prediction of a nonlinear degradation process is proved by a case study of commercial modular aero-propulsion system simulation data (C-MAPSS-Data) from NASA. Results also show that the proposed method requires less training time and has better prediction accuracy than other data-driven methods.
In this paper, a Lyaupnov-based finite control set model predictive direct torque control for the permanent magnet synchronous machine (PMSM) is proposed. In the proposed control scheme, the finite ...control set prediction and the Lyapunov theory are combined to minimize the torque ripple. The eight voltage vectors of the two-level converter are utilized as a finite control set for the torque prediction of the PMSM. A cost function considering the torque error, the maximum torque per ampere operation and the current limitation is introduced. Comparing to the conventional finite control set predictive control, the dominant part of the cost function is utilized as a Lyapunov function to estimate the duty cycle of each voltage vector. An optimum voltage can be obtained by the optimum voltage vector from the eight vectors and their duty cycles. A small sampling frequency and a fixed switching frequency can be realized when compared to the conventional finite set model predictive control. In the end, the simulation and experimental results validate the performance of the proposed control scheme.
Super-luminous supernovae (SLSNe) are tremendously luminous explosions whose power sources and progenitors are highly debated. Broad-lined SNe Ic (SNe Ic-bl) are the only type of SNe that are ...connected with long-duration gamma-ray bursts (GRBs). Studying the spectral similarity and difference between the populations of hydrogen-poor SLSNe (SLSNe Ic) and of hydrogen-poor stripped-envelope core-collapse SNe, in particular SNe Ic and SNe Ic-bl, can provide crucial observations to test predictions of theories based on various power source models and progenitor models. In this paper, we collected all of the published optical spectra of 32 SLSNe Ic, 21 SNe Ic-bl, as well as 17 SNe Ic, quantified their spectral features, constructed average spectra, and compared them in a systematic way using new tools we have developed. We find that SLSNe Ic and SNe Ic-bl, including those connected with GRBs, have comparable widths for their spectral features and average absorption velocities at all phases. Thus, our findings strengthen the connection between SLSNe Ic and GRBs. In particular, SLSNe Ic have average Fe ii λ5169 absorption velocities of −15,000 2600 km s−1 at 10 days after peak, which are higher than those of SNe Ic by ∼7000 km s−1 on average. SLSNe Ic also have significantly broader Fe ii λ5169 lines than SNe Ic. Moreover, we find that such high absorption and width velocities of SLSNe Ic may be hard to explain with the interaction model, and none of the 13 SLSNe Ic with measured absorption velocities spanning over 10 days has a convincing flat velocity evolution, which is inconsistent with the magnetar model in one dimension. Lastly, we compare SN 2011kl, the first SN connected with an ultra-long GRB, with the mean spectrum of SLSNe Ic and of SNe Ic-bl.
2-(2-Phenylethyl)chromones (PECs) are the principal constituents contributing to the distinctive fragrance of agarwood. How PECs are biosynthesized is currently unknown. In this work, we describe a ...diarylpentanoid-producing polyketide synthase (PECPS) identified from Aquilaria sinensis. Through biotransformation experiments using fluorine-labeled substrate, transient expression of PECPS in Nicotiana benthamiana, and knockdown of PECPS expression in A. sinensis calli, we demonstrate that the C
-C
-C
scaffold of diarylpentanoid is the common precursor of PECs, and PECPS plays a crucial role in PECs biosynthesis. Crystal structure (1.98 Å) analyses and site-directed mutagenesis reveal that, due to its small active site cavity (247 Å
), PECPS employs a one-pot formation mechanism including a "diketide-CoA intermediate-released" step for the formation of the C
-C
-C
scaffold. The identification of PECPS, the pivotal enzyme of PECs biosynthesis, provides insight into not only the feasibility of overproduction of pharmaceutically important PECs using metabolic engineering approaches, but also further exploration of how agarwood is formed.
In the early stages of the outbreak of coronavirus disease 2019 (COVID-19) in Hubei, China, the local health-care system was overwhelmed. Physicians and nurses who had no infectious disease expertise ...were recruited to provide care to patients with COVID-19. To our knowledge, no studies on their experiences of combating COVID-19 have been published. We aimed to describe the experiences of these health-care providers in the early stages of the outbreak.
We did a qualitative study using an empirical phenomenological approach. Nurses and physicians were recruited from five COVID-19-designated hospitals in Hubei province using purposive and snowball sampling. They participated in semi-structured, in-depth interviews by telephone from Feb 10 to Feb 15, 2020. Interviews were transcribed verbatim and analysed using Haase's adaptation of Colaizzi's phenomenological method.
We recruited nine nurses and four physicians. Three theme categories emerged from data analysis. The first was “being fully responsible for patients' wellbeing—‘this is my duty’”. Health-care providers volunteered and tried their best to provide care for patients. Nurses had a crucial role in providing intensive care and assisting with activities of daily living. The second category was “challenges of working on COVID-19 wards”. Health-care providers were challenged by working in a totally new context, exhaustion due to heavy workloads and protective gear, the fear of becoming infected and infecting others, feeling powerless to handle patients' conditions, and managing relationships in this stressful situation. The third category was “resilience amid challenges”. Health-care providers identified many sources of social support and used self-management strategies to cope with the situation. They also achieved transcendence from this unique experience.
The intensive work drained health-care providers physically and emotionally. Health-care providers showed their resilience and the spirit of professional dedication to overcome difficulties. Comprehensive support should be provided to safeguard the wellbeing of health-care providers. Regular and intensive training for all health-care providers is necessary to promote preparedness and efficacy in crisis management.
National Key R&D Program of China, Project of Humanities and Social Sciences of the Ministry of Education in China.
In recent times, fused aromatic diketopyrrolopyrrole (DPP)‐based functional semiconductors have attracted considerable attention in the developing field of organic electronics. Over the past few ...years, DPP‐based semiconductors have demonstrated remarkable improvements in the performance of both organic field‐effect transistor (OFET) and organic photovoltaic (OPV) devices due to the favorable features of the DPP unit, such as excellent planarity and better electron‐withdrawing ability. Driven by this success, DPP‐based materials are now being exploited in various other electronic devices including complementary circuits, memory devices, chemical sensors, photodetectors, perovskite solar cells, organic light‐emitting diodes, and more. Recent developments in the use of DPP‐based materials for a wide range of electronic devices are summarized, focusing on OFET, OPV, and newly developed devices with a discussion of device performance in terms of molecular engineering. Useful guidance for the design of future DPP‐based materials and the exploration of more advanced applications is provided.
Diketopyrrolopyrrole (DPP) is one of the most promising building blocks for the construction of semiconductors for organic electronics. Inspired by their success in organic field‐effect transistors and organic solar cells, DPP‐based semiconductors have been introduced into more devices. The DPP‐based semiconductors used for a wide range of electronic devices are summarized.
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