Orbital angular momentum (OAM) at radio frequency (RF) provides a novel approach of multiplexing a set of orthogonal modes on the same frequency channel to achieve high spectrum efficiencies. ...However, there are still big challenges in the multi-mode OAM generation, OAM antenna alignment and OAM signal reception. To solve these problems, we propose an overall scheme of the line-of-sight multi-carrier and multi-mode OAM (LoS MCMM-OAM) communication based on uniform circular arrays (UCAs). First, we verify that UCA can generate multi-mode OAM radio beam with both the RF analog synthesis method and the baseband digital synthesis method. Then, for the considered UCA-based LoS MCMM-OAM communication system, a distance and AoA estimation method is proposed based on the two-dimensional ESPRIT (2-D ESPRIT) algorithm. A salient feature of the proposed LoS MCMM-OAM and LoS MCMM-OAM-MIMO systems is that the channel matrices are completely characterized by three parameters, namely, the azimuth angle, the elevation angle and the distance, independent of the numbers of subcarriers and antennas, which significantly reduces the burden by avoiding estimating large channel matrices, as traditional MIMO-OFDM systems. After that, we propose an OAM reception scheme including the beam steering with the estimated AoA and the amplitude detection with the estimated distance. At last, the proposed methods are extended to the LoS MCMM-OAM-MIMO system equipped with uniform concentric circular arrays (UCCAs). Both mathematical analysis and simulation results validate that the proposed OAM reception scheme can eliminate the effect of the misalignment error of a practical OAM channel and approaches the performance of an ideally aligned OAM channel.
Aryne insertions into the carbon‐iodine bond of heteroaryl iodides has been achieved for the first time. This novel reaction provides an efficient pathway for the synthesis of valuable building ...blocks 2‐iodoheterobiaryls from heteroaryl iodides and o‐silylaryl triflates in excellent regioselectivity. The copper(I) catalyst, which bears a N‐heterocyclic carbene (NHC) ligand, is essential to accomplish the reaction. Control reactions and DFT calculations indicate that the coordination of copper, as a Lewis acid, with nitrogen atoms of heteroaryl iodides mediates the insertion of arynes into heteroaryl carbon‐iodine bonds.
Cu‐catalyzed aryne insertion into heteroaryl C−I bonds to access valuable building blocks 2‐iodoheterobiaryls, characterized by high efficiency and selectivity, has first been realized. The newly discovered Lewis acid catalyzed insertion model opens up numerous opportunities for the further development of aryne chemistry.
Residual dipolar coupling (RDC) is a powerful structural parameter for the determination of the constitution, conformation, and configuration of organic molecules. Herein, we report the first liquid ...crystal‐based orienting medium that is compatible with MeOH, thus enabling RDC acquisitions of a wide range of intermediate to polar organic molecules. The liquid crystals were produced from self‐assembled oligopeptide nanotubes (AAKLVFF), which are stable at very low concentrations. The presented alignment medium is highly homogeneous, and the size of RDCs can be scaled with the concentration of the peptide. To assess the accuracy of the RDC measurement by employing this new medium, seven bioactive natural products from different classes were chosen and analyzed. The straightforward preparation of the anisotropic alignment sample will offer a versatile and robust protocol for the routine RDC measurement of natural products.
Alignment medium: A novel, robust, versatile anisotropic medium composed of self‐assembled peptides, which are stable at very low concentrations, is used for the measurement of residual dipolar couplings (RDCs) in MeOH. The presented alignment medium is highly homogeneous, and the size of RDCs can be scaled with the concentration of the peptide.
Owing to the high economic efficiency and energy density potential, manganese‐based layer‐structured oxides have attracted great interests as cathode materials for potassium ion batteries. In order ...to alleviate the continuous phase transition and K+ re‐embedding from Jahn‐Teller distortion, the Mn‐Co‐MoO6 octahedra are introduced into P3‐K0.45MnO2 herein to optimize the local electron structure. Based on the experimental and computational results, the octahedral center metal molybdenum in MoO6 octahedra proposes a smaller ionic radius and higher oxidation state to induce second‐order JTE (pseudo‐JTE) distortion in the adjacent MnO6 octahedra. This distortion compresses the MnO6 octahedra along the c‐axis, leading to an increased interlayer spacing in the K+ layer. Meanwhile, the Mn3+/Mn4+ is balanced by CoO6 octahedra and the K+ diffusion pathway is optimized as well. The proposed P3‐K0.45Mn0.9Co0.05Mo0.05O2 cathode material shows an enhanced cycling stability and rate performance. It demonstrates a high capacity of 80.2 mAh g−1 at 100 mAh g−1 and 77.3 mAh g−1 at 500 mAh g−1. Furthermore, it showcases a 2000 cycles stability with a 59.6% capacity retention. This work presents a promising solution to the challenges faced by manganese‐based layered oxide cathodes and offers a deep mechanism understanding and improved electrochemical performance.
The Mn‐Co‐MoO6 octahedra are introduced into P3‐K0.45MnO2 to optimize the local electron structure. The MoO6 propose an empty outermost electrons (4d05s0) orbitals structure and the smaller ionic radius and higher oxidation state can induce a second‐order JTE distortion in the adjacent MnO6 octahedra. Co3+ do not induce Jahn‐Teller effects due to the empty electron in eg orbital.
•We study the dynamics of epidemic spreading on signed networks.•We propose a modified signed-susceptible-infectious-susceptible epidemiological model.•We use the Monte Carlo method and the mean ...field analysis for our reseach.•We determine the peak fraction of infected nodes and the epidemic thresholds.•We discuss the implications of our results for the optimal mitigation of epidemic spreading.
Over the past two decades, epidemic spreading on complex network has been a vibrant and highly successful research avenue. The dynamics of epidemic spreading on signed networks has nonetheless received fairly little attention. Signed networks contain edges that are labeled as either positive or negative, in relation to their propensity to either accelerate or mitigate epidemic spreading. To that effect, we here propose a modified signed-susceptible-infectious-susceptible epidemiological model, which incorporates positive and negative transmission rates based on structural balance theory. We also consider dynamical transmission rates to determine the influence of structural balance on the dynamics of epidemic spreading. We use Erdős-Rényi random networks and Barabási-Albert scale-free networks, together with the Monte Carlo method, to determine the peak fraction of infected nodes and the epidemic thresholds. We also use the mean field analysis to show analytically the origin of the computationally obtained results, although of course the agreement is not perfect due to the impact of network structure.
Nanographene with a Nitrogen‐Doped Cavity Wang, Fei‐Fan; Wang, Yu‐Xiang; Wu, Qiong ...
Angewandte Chemie International Edition,
January 8, 2024, Volume:
63, Issue:
2
Journal Article
Peer reviewed
Nitrogen‐doped cavities are pervasive in graphenic materials, and represent key sites for catalytic and electrochemical activity. However, their structures are generally heterogeneous. In this study, ...we present the synthesis of a well‐defined molecular cutout of graphene featuring N‐doped cavity. The graphitization of a macrocyclic pyridinic precursor was achieved through photochemical cyclodehydrochlorination. In comparison to its counterpart with pyridinic nitrogen at the edges, the pyridinic nitrogen atoms in this nanographene cavity exhibit significantly reduced basicity and selective binding to Ag+ ion. Analysis of the protonation and coordination equilibria revealed that the tri‐N‐doped cavity binds three protons, but only one Ag+ ion. These distinct protonation and coordination behaviors clearly illustrate the space confinement effect imparted by the cavities.
A nanographene with a tri‐N‐doped cavity was synthesized by photo‐induced cyclization. In comparison with nitrogen‐doping at the edge, this tri‐N‐doped holey nanographene exhibited markedly reduced basicity and selective affinity toward Ag+. This nanographene with a N‐doped cavity provides a precise model for understanding the binding in the nano‐confined defects of graphenic materials.
Silicosis is a systemic disease caused by long-term inhalation of free SiO
and retention in the lungs. At present, it is still the most important occupational health hazard disease in the world. ...Existing studies have shown that non-coding RNA can also participate in complex fibrosis regulatory networks. However, its role in regulating silicotic fibrosis is still unclear. In this study, we constructed a NR8383/RLE-6TN co-culture system to simulate the pathogenesis of silicosis in vitro. Design of miR-204-3p mimics and inhibitors to overexpress or downregulate miR-204-3p in RLE-6TN cells. Design of short hairpin RNA (sh-RNA) to downregulate MRAK052509 in RLE-6TN cells. The regulatory mechanism of miR-204-3p and LncRNA MRAK052509 on EMT process was studied by Quantitative real-time PCR, Western blotting, Immunofluorescence and Cell scratch test. The results revealed that miR-204-3p affects the occurrence of silica dust-induced cellular EMT process mainly through regulating TGF-βRΙ, a key molecule of TGF-β signaling pathway. In contrast, Lnc MRAK052509 promotes the EMT process in epithelial cells by competitively adsorbing miR-204-3p and reducing its inhibitory effect on the target gene TGF-βRΙ, which may influence the development of silicosis fibrosis. This study perfects the targeted regulation relationship between LncRNA MRAK052509, miR-204-3p and TGF-βRΙ, and may provide a new strategy for the study of the pathogenesis and treatment of silicosis.
Radio frequency-orbital angular momentum (RF-OAM) is a novel approach of multiplexing a set of orthogonal modes on the same frequency channel to achieve high spectrum efficiencies. Since OAM requires ...precise alignment of the transmit and the receive antennas, the electronic beam steering approach has been proposed for the uniform circular array (UCA)-based OAM communication system to circumvent large performance degradation induced by small antenna misalignment in practical environment. However, in the case of large-angle misalignment, the OAM channel capacity cannot be effectively compensated only by the electronic beam steering. To solve this problem, we propose a hybrid mechanical and electronic beam steering scheme, in which mechanical rotating devices controlled by pulse width modulation (PWM) signals as the execution unit are utilized to eliminate the large misalignment angle, while electronic beam steering is in charge of the remaining small misalignment angle caused by perturbations. Furthermore, due to the interferometry, the receive signal-to-noise ratios (SNRs) are not uniform at the elements of the receive UCA. Therefore, a rotatable UCA structure is proposed for the OAM receiver to maximize the channel capacity, in which the simulated annealing algorithm is adopted to obtain the optimal rotation angle at first, then the servo system performs mechanical rotation, at last the electronic beam steering is adjusted accordingly. Both mathematical analysis and simulation results validate that the proposed hybrid mechanical and electronic beam steering scheme can effectively eliminate the effect of diverse misalignment errors of any practical OAM channel and maximize the OAM channel capacity.
Summary
We aimed to identify the efficacy of haploidentical related donor (HID) haematopoietic stem cell transplantation (HSCT) in adolescent and young adults (AYAs) with acute myeloid leukaemia ...(AML) in a large cohort. Consecutive AML AYAs (15–39 years old, n = 599) receiving HID HSCT in complete remission (CR) were included. The 3‐year cumulative incidence of measurable residual disease occurrence, relapse and non‐relapse mortality after HID HSCT was 28.6% (95% CI: 25.0–32.2), 11.6% (95% CI: 9.0–14.2) and 6.7% (95% CI: 4.7–8.7) respectively. The 3‐year probability of event‐free survival, leukaemia‐free survival (LFS) and overall survival (OS) after HID HSCT was 60.7% (95% CI: 56.9–64.8), 81.7% (95% CI: 78.7–84.9) and 85.6% (95% CI: 82.8–88.4) respectively. In multivariable analysis, AML risk category at diagnosis and comorbidity burdens before HID HSCT were independently associated with LFS and OS. Compared to the older adults (≥ 40 years, n = 355) with AML receiving HID HSCT in CR during the same time period, AYAs have a lower incidence of non‐relapse mortality and higher probabilities of LFS and OS. Thus, we firstly confirmed the safety and efficacy of HID HSCT in AYAs with AML‐CR.
The 3‐year probabolities of overall survival after haploidentical related donor haematopoitic stem cell transplantation according to (A) favourable‐, intermidiate‐ and poor‐risk acute myeloid leukaemia category at diagnosis and (B) low‐ intermidiate‐ and high‐risk haematopoietic stem cell transplantation‐specific comorbidity index scores before allo‐ haematopoietic stem cell transplantation.
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