Search

A base-mediated domino reaction of ortho-carbonylated alkynyl-substituted arenealdehydes with indoles has been developed, and a variety of indolyl-substituted isobenzofuran derivatives can be rapidly obtained in high yields. Notably, the selective N-alkylation of indoles and 5-exo-dig cyclization of alkynes can be achieved efficiently to give N-functionalized products. This reaction involves a domino procedure for the formation of two bonds under simple conditions and has a broad substrate scope. [ABSTRACT FROM AUTHOR]

Herein we describe a reaction of ortho-carbonylated alkynyl-substituted arylaldehydes with common primary amines that can provide functionalized isoindolinone and 3-hydroxylindenamine products in high yields. Depending on the substituent size of primary amines, two distinct reaction pathways were exploited selectively, that are, an initial aza-conjugate addition followed by hydrogen transfer to access isoindolinone framework and a unique oxa-conjugate addition followed by Petasis-Ferrier rearrangement to afford indenamine derivatives. In the presence of Et3N, the reaction property of small primary amines was changed, proceeding to afford 3-hydroxylindenamine derivatives efficiently. These products contain interesting substructures that exist in many natural products and bioactive molecules. The reaction features contain the use of transition-metal-free catalysts, simple operation, broad substrate scope, and product diversity. [ABSTRACT FROM AUTHOR]

An unprecedented access to strained tetracyclic bridgehead alkenes by reaction of easily accessible ortho-alkynylarylaldehydes with conjugated dienes is described. The process involves a chemo- and stereo-selective, gold-catalyzed, tandem intermolecular [3+2] cycloaddition/Prins-type ring-closing reaction that allows generating structural complexity in a straightforward manner. This approach for the preparation of anti-Bredt compounds is synthetically superior to those previously reported: the procedure is easy to implement, operates under mild experimental conditions, is efficient, and exhibits a good substrate scope. [ABSTRACT FROM AUTHOR]

To attain overall recognition of the effect of Nakagami-m channel parameters on the second-order statistics and to present a guide to the design and configuration of systems, we investigate the average level crossing rate (LCR) and average fading duration (AFD) of multiuser single relay cooperation wireless communications, in which the multiple mobile users communicate with base station under the help of single relay. On the basis of the statistical channel state information (CSI) between mobile users and relay, a single user is selected to communicate with base station. For the multiuser relay cooperation communications, we first present the integral expressions to the LCR and AFD of equivalent end-to-end envelope by using strict mathematical proof. Then with appropriate approximation, we obtain the closed-form solutions to the upper and lower bounds of average LCR and AFD as well as the ones of Laplace approximation. Finally, on the basis of the derivations, we validate the approximations to LCR and AFD, and investigate the effect of the system parameters on LCR and AFD. The comparison results show that the derivations match well the simulations, and the exact values can be bounded by the obtained upper and lower bounds. [ABSTRACT FROM AUTHOR]

Glutamate receptors, especially N-methyl-d-aspartate (NMDA) receptors, are hypothesized to play key roles in opiate tolerance and withdrawal. There is also accumulating evidence that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonists and group II metabotropic glutamate receptor (mGluR) agonists attenuate opiate withdrawal. However, most existing data are derived from adult animal models. Glutamate receptor types undergo dramatic developmental changes during early life. Thus, the pharmacological effects on opiate withdrawal of NMDA receptor, AMPA receptor, and mGluR antagonists in the developing organism may not be comparable to those in the adult. Indeed, NMDA receptor antagonists do not block morphine tolerance or withdrawal in the 7-day-old rat, but are partially effective in the 14-day-old, and fully effective in the 21-day-old. Thus, there is a transition period around the second post-natal week for NMDA receptor antagonists to suppress opiate tolerance and withdrawal. A combination of in vivo and in vitro assays was used in the present studies to test the effect of drugs acting on AMPA and group II mGlu receptors on morphine withdrawal in rats at 7, 14, and 21 days of age. These ages represent the critical periods when various glutamate receptor subunits undergo differential change. In contrast to NMDA receptor antagonists’ early ineffectivness in suppressing morphine withdrawal, the AMPA receptor antagonist and the group II mGluR agonists were effective at all ages tested. Thus, for the human infant patient, pharmacotherapies to reduce opiate tolerance and withdrawal should focus on non-NMDA ionotropic and metabotropic receptors. [Copyright &y& Elsevier]

Objective: Metabolic dysfunction‐associated steatotic liver disease (MASLD) affects many populations, and screening out the high‐risk populations at an early stage is a challenge. As a sarcopenia index, the relationship between creatinine to cystatin C ratio (CCR) and MASLD remains unclear. This cross‐sectional, prospective study aimed to explore the relationship between CCR and MASLD. Design Firstly, explored the correlation between CCR and MASLD in cross‐sectional analyses. Then excluded the population with baseeline diagnosis of MASLD and analyzed the association with baseline CCR levels and the onset of MASLD in the population with available follow‐up data. Univariate and multivariate logistic regression analyses were used to calculate odds ratios (ORs) to evaluate the association between CCR levels and MASLD. Patients and Measurements: This study included 368,634 participants from the UK Biobank for cross‐sectional and prospective analyses. The demographic characteristics and laboratory measurements of all participants were obtained from the UK Biobank. MASLD was diagnosed according to the multi‐society consensus nomenclature. Hepatic steatosis was defined as FLI ≥60. Results: We grouped the study participants according to CCR tertiles. In cross‐sectional analyses, participants in CCR tertile 1 had the highest MASLD risk (OR: 1.070, 95% CI: 1.053−1.088, p <.001). And the similar association was observed in the prospective analyses (CCR tertile 1 OR: 1.340, 95% CI: 1.077−1.660, p =.009; CCR tertile 2 OR: 1.217, 95% CI: 1.021−1.450, p =.029, respectively). After stratification by gender, the significant association between CCR and the onset of MASLD was only observed in males (CCR tertile 1 OR: 1.639, 95% CI: 1.160−2.317, p =.005; CCR tertile 2 OR: 1.322, 95% CI: 1.073−1.628, p =.005, respectively). Conclusion: Our results indicated that lower CCR was significantly associated with higher risk of MASLD, based on which predictive models can be developed to screen populations at high risk of developing MASLD. [ABSTRACT FROM AUTHOR]

An abstract of the article "Synthesis of Multisubstituted N-(Tosylamino)pyrrole Derivatives by AuCl3-Catalyzed Cycloisomerization of the β-Alkynyl Hydrazones" by Z. Cao, H. Zhu, and X. Meng is presented.

Background: Cancer metastasis is still a life threat to patients with colorectal cancer (CRC). Brain and muscle ARNT‐like protein 1 (BMAL1) is an important biological proteins that can regulate the behavior of cancer cells and their response to chemotherapy. However, the role of BMAL1 in the tumorigenic phenotype of CRC remains unclear. Here, we aim to investigate the functional role and mechanisms of BMAL1 in CRC. Methods: The mRNA expression of BMAL1 was studied using the Cancer Genome Atlas (TCGA) databases. The protein level in clinical tissues was confirmed by immunohistochemistry (IHC). The effects of BMAL1 on the epithelial‐to‐mesenchymal transition (EMT) and proliferation of CRC cell lines (including BMAL1 overexpressed or silencing cells) were studied by Transwell, wound healing, CCK‐8 and colony formation experiments. A series of experiments were conducted to demonstrate the mechanisms of BMAL1 regulating EMT and cancer proliferation in vitro and in vivo. Results: We found that BMAL1 expression was closely related to the poor prognosis of CRC. BMAL1 overexpression promoted cell proliferation and migration. Mechanistically, we found that BMAL1 may activate the epithelial‐to‐mesenchymal transition (EMT) pathway and induce the β‐catenin release further promotes the expression of oncogene c‐Myc and the migration of colorectal cells by activating MAPK pathway. However, BMAL1 silencing achieved the opposite effect. In addition, blocking MAPK‐signaling pathway with specific inhibitors of ERK1/2 and JNK can also downregulate the expressions of c‐Myc in vitro. Taken together, these results suggested that the BMAL1/ c‐Myc‐signaling pathway may regulate the metastasis of CRC through the JNK/ERK1/2 MAPK‐dependent pathway. Conclusions: Our study showed that BMAL1 promotes CRC metastasis through MAPK‐c‐Myc pathway. These results deepen our understanding of the relationship between BMAL1 and tumorigenic phenotypes, which may become a promising therapeutic target for BMAL1 overexpressing CRC. [ABSTRACT FROM AUTHOR]

The surface ligand environment plays a dominant role in determining the physicochemical, optical, and electronic properties of colloidal quantum dots (CQDs). Specifically, the ligand‐related electronic traps are the main reason for the carrier nonradiative recombination and the energetic losses in colloidal quantum dot solar cells (CQDSCs), which are usually solved with numerous advanced ligand exchange reactions. However, the synthesis process, as the essential initial step to control the surface ligand environment of CQDs, has lagged behind these post‐synthesis ligand exchange reactions. The current PbS CQDs synthesis tactic generally uses lead oxide (PbO) as lead precursor, and thus suffers from the water byproducts issue increasing the surface‐hydroxyl ligands and aggravating trap‐induced recombination in the PbS CQDSCs. Herein, an organic‐Pb precursor, lead (II) acetylacetonate (Pb(acac)2), is used instead of a PbO precursor to avoid the adverse impact of water byproducts. Consequently, the Pb(acac)2 precursor successfully optimizes the surface ligands of PbS CQDs by reducing the hydroxyl ligands and increasing the iodine ligands with trap‐passivation ability. Finally, the Pb(acac)2‐based CQDSCs possess remarkably reduced trap states and suppressed nonradiative recombination, generating a certified record Voc of 0.652 V and a champion power conversion efficiency (PCE) of 11.48% with long‐term stability in planar heterojunction‐structure CQDSCs. [ABSTRACT FROM AUTHOR]

Metasurfaces have an exceptional capacity to manipulate the phase, amplitude, polarization, or spectrum of light. However, unit cells, or meta‐atoms, of metasurfaces are conventionally designed using regular shapes, limiting performance improvement. The utilization of metasurfaces with freeform shaped meta‐atoms for on‐chip ultraspectral imaging is proposed, where the freeform shaped patterns are generated with controllable feature sizes and boundary curvatures for feasible fabrication. These patterns broaden design diversity and enrich metasurface‐unit spectral response with complicated Bloch modes, thus improving spectral imaging performance with enhanced spectrum recovery precision for broadband spectra and smaller center‐wavelength deviation for narrowband spectra. A snapshot on‐chip ultraspectral imaging, with 356 × 436 spectral pixels is experimentally demonstrated. Spectral resolution is state‐of‐the‐art, at 0.5 nm, and mean fidelity of spectral reconstruction for a standard color board reaches 98.78%. These results support future applications in the field of precise intelligent perception. Moreover, the generating method for freeform shaped patterns also benefits for the forward and inverse designs for high‐performance metasurfaces. [ABSTRACT FROM AUTHOR]

SUMMARY The heterogeneous networks belonging to different service providers form a coalition system for maximizing the profit, where they may either compete or cooperate with each other. In this paper, we introduce the Lokta-Volterra model, a differential dynamics model, to build the competitive and cooperative mechanisms of heterogeneous networks. It considers the natural growth rate of the network itself and competitive and cooperative effects among networks. Then, according to the ordinary differential principle, the stability of the proposed model and its equilibrium points are analyzed. And finally, system performances are evaluated by Vensim that is used for developing, analyzing, and packaging dynamic feedback models. Analysis and simulation results show that the natural growth rate of the network cannot increase its profit, but effective cooperative mechanism among heterogeneous networks can increase the profit of each network. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper considered the single relay system and proposed a novel repetition coding decode-and-forward (DF) cooperative transmission scheme on the basis of superposition coding and partial relaying. In the proposed scheme, the link disparity due to the geometry of the relay network is emphasized, and only a fraction of the information is transmitted in relay mode with the rest being transmitted directly, which benefits from the utility of superposition coding (SC) in broadcast situation. The proposed scheme is analyzed in two cases, one assumes full channel state information at the source (full CSIS), the other with only mean gain of each link known by the source (partial CSIS). For both cases, the optimal design of system parameters is considered. We investigate the achievable rate and expected rate performance for these two cases, respectively. The proposed schemed is well compared with conventional repetition coding DF, parallel coding DF, as well as another promising superposition coding relaying. It is concluded that, by designing protocols that orients to certain network geometry, better trade-off between performance and complexity can be obtained. The analysis reveals that the gap between conventional repetition and parallel coding is largely mitigated by the proposed scheme, quite for the scenario that the relay locates relatively but not extremely closer to the source, at moderate SNR regime for both partial and full CSIS cases. The proposed scheme becomes more beneficial in severe path loss attenuation scenario. [ABSTRACT FROM AUTHOR]

Micro multiple quantum well (MQW) III‐nitride diodes usually function as micro light‐emitting diodes, which are considered the next generation of display technology. In addition to both illumination and display, MQW III‐nitride diodes in theory have the capability to both detect and modulate light. Here, proof that the III‐nitride diode can simultaneously emit and detect light is experimentally confirmed by a wireless light communication system using two identical devices. The 20 × 20 MQW III‐nitride diodes are monolithically integrated into a single chip and a real‐time imaging system of transmitted images is established, which in practice can perform display, illumination, imaging, and simultaneous illumination‐imaging operations. These functions can be software controlled and switched freely. This work may lead to a multifunctional display that merges millions of III‐nitride diodes together to perform these functions at the same time. [ABSTRACT FROM AUTHOR]

Ultra‐dense networking is considered an effective solution to achieve high capacity in 5G networks. However, the densely distributed base stations (BSs) in ultra‐dense networks (UDNs) make the inter‐cell interference much more serious than that in traditional cellular networks. Therefore, it is important to mitigate inter‐cell interference in the UDNs to improve network performance. To tackle this problem, we propose a novel virtual resource mapping algorithm that includes a resource reservation (RR) algorithm and a real‐time resource embedding (RE) algorithm. Specifically, according to the number of services predicted by a dynamic service model, the RR algorithm is proposed to determine the sets of multiplexing BSs in the next time cycle and reserve channel resource required by each BS. Then, to further reduce inter‐cell interference, the real‐time RE algorithm is proposed to allocate the channel resource in real time. Finally, simulation results show that the proposed algorithm has better performance in terms of signal‐to‐interference‐plus‐noise ratio and acceptance ratio, compared to the existing algorithms, such as the frequency reuse channel allocation algorithm and inter‐cell interference coordination algorithm. [ABSTRACT FROM AUTHOR]

A novel gold(III) and TfOH‐cocatalyzed reaction of ortho‐alkynylbenzaldehydes with cyclopropenes was described for the synthesis of a variety of functionalized benzo[7]annulene derivatives in a highly stereoselective manner. This reaction could undergo tandem [4+2] cycloaddition/ring expansion to achieve the construction of seven‐membered‐carbocycles, along with the cleavage of double bond of cyclopropenes. The reaction features simple operations, commercially available catalysts and broad substrate scope with good efficiencies. The reaction of strained cyclopropenes with ortho‐alkynylarylaldehydes by gold and TfOH cocatalysis was developed for the synthesis of functionalized benzo[7]annulene derivatives with high stereoselectivity. The cleavage of double bond of cyclopropenes was achieved by tandem [4+2] cycloaddition and ring expansion. [ABSTRACT FROM AUTHOR]

Abstract: The Three Gorges are considered to be critical to understand the formation of Yangtze River. Recent research results suggest that the Yangtze Three Gorges was created during the Quaternary but the exact time is debatable. Fe–Ti oxide minerals are seldom used to study sediment provenance, expecially using scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). In this study, the provenance of Quaternary sediments in Yichang area, which is located to the east of the Yangtze Three Gorges, was investigated by using SEM and EDS to research Fe–Ti oxides. The Panzhihua vanadium titanomagnetite and Emeishan basalt outcrop are located to the west of the Three Gorges. Further, the materials from them are observed in the Quaternary sediments of Yichang area. Fe–Ti oxide minerals from the Huangling granite are observed in the Yunchi and Shanxiyao Formations, which were formed before 0.75 Ma B.P., whereas Fe–Ti oxide minerals from the Huangling granite, Panzhihua vanadium titanomagnetite, and Emeishan basalt are observed in the riverbed and fifth‐terrace sediments of the Yangtze River, which were formed after 0.73 Ma B.P.. Thus, we can infer that the Three Gorges formed after the deposition of the Shanxi Formation and before the fifth‐terrace; i.e., 0.75–0.73 Ma B.P.. [ABSTRACT FROM AUTHOR]

For us to meet the green and reliable communication requirement by the forthcoming fifth generation mobile networks, this paper focuses on a secrecy constrained device-to-device (D2D) underlay massive multiple-input multiple-output hybrid network, where the D2D user (DU) and cellular user (CU) links are exposed to passive malicious eavesdroppers. The D2D transmitters harvest the power from the signals of dedicated power beacons (PBs), but also the ambient radio frequency (RF) interference of CUs. The signals of PBs are known previously at the receivers of both the D2D and cellular users but are not known at eavesdroppers so that it can be regarded as an artificial noise. For the interested hybrid networks, we first present an energy-harvesting scheme based on the inversion power control where the power received at the corresponding receiver is higher than the receiver's sensitivity. Then, by modeling the locations of network elements as Poisson point process and applying stochastic geometry, we derive the sufficient probability that a typical D2D transmitter harvests sufficient energy to establish communication links. Finally, with the derived sufficient probability, we evaluate the performance of the CUs and DUs in the achievable ergodic rate and the secrecy outage probability. Both the analytical and simulated results show that precious power of network is saved because of the ambient RF interference exploited, and the secrecy of both D2D and cellular links is improved simultaneously because of the signal of PBs modeled as artificial noises at CUs and DUs. [ABSTRACT FROM AUTHOR]

In this paper, the cognitive relay cooperation (CRC) wireless communication systems are investigated over Nakagami- m fading channels. The decode-and-forward (DF) relay is employed to assist the communications between cognitive source and destination. Especially, to achieve full diversity order, we consider the case in which there is a direct path between cognitive source and destination. Besides the interference at primary users (PUs) created by secondary users (SUs), the interference at SUs created by PUs is also considered. For the interested CRC systems, we first achieve the exact expression for the CDF of the equivalent end-to-end signal-to-interference ratio (SIR) of CRC systems. Then, with the exact CDF, the exact average symbol error ratio (SER) and outage performance of CRC systems are achieved. The derivation is of significance, by which we can obtain a detailed knowledge about CRC systems. Though a single integral included in the derivation, it can be calculated numerically by employing some mathematical tools such as Matlab. At the same time, to obtain the insight and highlight the effect of system parameters on the considered CRC systems, by using the high SIR approximation, we obtain the asymptotic closed-form expression of CDF as well as the ones of average SER and outage probability. From the asymptotic results, we can find the main factors that dominate the performance of CRC systems. The presented simulation results for outage probability and average SER show the derivations and simulations are in agreement. Moreover, in high SIR the achieved asymptotic results match well the exact ones. As a result, in high SIR we can employ the asymptotic closed-form solutions to evaluate the exact performance of CRC systems. This can reduce greatly the implementation complexity. Besides this, the simulations also show that the diversity order is dominated by the fading severities of the secondary systems, i.e. the diversity order be proportional to the summation of the minimum fading severity between the two hops and that of the direct link. In contrast, the parameters of the primary systems only affect the coding gain, not the diversity gain. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ultraspectral Imaging Based on Metasurfaces with Freeform Shaped Meta-Atoms (Laser Photonics Rev. 16(7)/2022) B On-Chip Ultraspectral Imaging b In article number 2100663, Jiawei Yang, Kaiyu Cui, Yidong Huang and colleagues demonstrate a snapshot on-chip ultraspectral imager based on freeform metasurfaces with both high spatial resolution of 356 × 436 and spectral resolution of 0.5 nm, which will provide a new paradigm for future intellisense. The freeform shaped meta-atoms are generated with a proposed general method and could be utilized in forward or inverse design of other novel metasurfaces. [Extracted from the article]

The quantum chemistry polarizable force field program (QuanPol) is implemented to perform combined quantum mechanical and molecular mechanical (QM/MM) calculations with induced dipole polarizable force fields and induced surface charge continuum solvation models. The QM methods include Hartree-Fock method, density functional theory method (DFT), generalized valence bond theory method, multiconfiguration self-consistent field method, Møller-Plesset perturbation theory method, and time-dependent DFT method. The induced dipoles of the MM atoms and the induced surface charges of the continuum solvation model are self-consistently and variationally determined together with the QM wavefunction. The MM force field methods can be user specified, or a standard force field such as MMFF94, Chemistry at Harvard Molecular Mechanics (CHARMM), Assisted Model Building with Energy Refinement (AMBER), and Optimized Potentials for Liquid Simulations-All Atom (OPLS-AA). Analytic gradients for all of these methods are implemented so geometry optimization and molecular dynamics (MD) simulation can be performed. MD free energy perturbation and umbrella sampling methods are also implemented. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

An abstract of the article "Synthesis of Multisubstituted N-(Tosylamino)pyrrole Derivatives by AuCl3-Catalyzed Cycloisomerization of the β Alkynyl Hydrazones" by Ziping Cao and colleagues are presented.