Large multi-input multi-output (MIMO) systems with tens or hundreds of antennas have shown great potential for next generation of wireless communications to support high spectral efficiencies. ...However, due to the non-deterministic polynomial hard nature of MIMO detection, large MIMO systems impose stringent requirements on the design of reliable and computationally efficient detectors. Recently, lattice reduction (LR) techniques have been applied to improve the performance of low-complexity detectors for MIMO systems without increasing the complexity dramatically. Most existing LR algorithms are designed to improve the orthogonality of channel matrices, which is not directly related to the error performance. In this paper, we propose element-based lattice reduction (ELR) algorithms that reduce the diagonal elements of the noise covariance matrix of linear detectors and thus enhance the asymptotic performance of linear detectors. The general goal is formulated as solving a "shortest longest vector reduction" or a stronger version, "shortest longest basis reduction," both of which require high complexity to find the optimal solution. Our proposed ELR algorithms find sub-optimal solutions to the reductions with low complexity and high performance. The fundamental properties of the ELR algorithms are investigated. Simulations show that the proposed ELR-aided detectors yield better error performance than the existing low-complexity detectors for large MIMO systems while maintaining lower complexity.
Until now, there have been no ideal alternatives to replace non-human primates (NHPs) in biomedical research, yet the debate on whether it is appropriate to sacrifice NHPs for research never stops. ...With recent advances in genomics and the appearance of new technologies, the time is right to return to the problem of finding solutions to balance the welfare of both humans and NHPs.
Performance degradation and safety issue caused by Li dendrite growth and huge volume variation hinder the practical application of Li metal anode in high‐energy‐density lithium batteries. Li ...diffusion barrier of the host is a key parameter that determines the dendrite growth. Herein, a stable Li21Si5 alloy host with very low Li diffusion barriers is designed and prepared by an in situ metallurgical method using low‐cost micron silicon precursor. The low diffusion barrier of Li21Si5 host enables a dendrite‐free Li deposition behavior. It is revealed that the in‐situ formed porous Li21Si5 host not only has high Li affinity, but also suppresses volume variation of the electrode effectively and thus keeps superior structural stability during Li stripping and plating processes. As a result, this new Li metal anode with Li21Si5 host exhibits promising cycle stability and rate capability with low polarization in both symmetric and full cells. This study opens new opportunities for using alloy‐based materials as the hosts for Li composite anodes.
An in situ formed Li21Si5 alloy host prepared via a metallurgical method using a low‐cost micron silicon precursor possesses very low Li diffusion barriers. The resulted Li@Li21Si5 electrode demonstrates a dendrite‐free Li deposition behavior, ensuring promising electrochemical performance.
The emergence of virtual influencers, who possess realistic human-like appearances and intelligence, has provided new opportunities for brand endorsement strategy and gradually become an innovative ...trend. As the effectiveness of influencer endorsement is rooted in parasocial relationships, it remains unknown whether this effect can be extended to virtual influencers. With a focus on endorsement, the current study investigated the impact of human-like virtual influencers on parasocial relationships and their further outcomes. Two scenario-based experiments spanning two cultural contexts (Studies 1 and 2) provided sufficient evidence that users build weaker parasocial relationships with human-like virtual influencers due to the lower emotional engagement involved, which results in lower endorsement effectiveness in terms of brand interest and purchase intention. Moreover, a novel moderation role of influencer post modality (image vs. video) was found to attenuate the negative effect of human-like virtual influencers. The findings contribute to enhancing the understanding of users’ relationship building with virtual influencers, and offer suggestions for influencer endorsements and communication strategies for virtual influencers.
Herein, we report transition-metal-catalyzed B–H bond insertion reactions between borane adducts and alkynes to afford organoboron compounds in excellent yields under mild reaction conditions. This ...successful use of alkynes as carbene precursors in these reactions constitutes a new route to organoboron compounds. The starting materials are safe and readily available, and the reaction exhibits 100% atom-economy. Moreover, an asymmetric version catalyzed by chiral dirhodium complexes produced chiral boranes with excellent enantioselectivity (up to 96% ee). This is the first report of highly enantioselective heteroatom–hydrogen bond insertion reactions of metal carbenes generated in situ from alkynes. The chiral products of the reaction could be easily transformed to widely used borates and diaryl methanol compounds without loss of optical purity, which demonstrates its potential utility in organic synthesis. A kinetics study indicated that the Cu-catalyzed B–H bond insertion reaction is first order with respect to the catalyst and the alkyne and zero order with respect to the borane adduct, and no kinetic isotopic effect was observed in the reaction of the adduct. These results, along with density functional theory calculations, suggest that the formation of the Cu carbene is the rate-limiting step and that the B–H bond insertion is a fast, concerted process.
Purpose
This study aims to develop liposomal formulations containing synergistic antibiotics of colistin and ciprofloxacin for the treatment of infections caused by multidrug-resistant
Pseudomonas ...aeruginosa
.
Methods
Colistin (Col) and ciprofloxacin (Cip) were co-encapsulated in anionic liposomes by ammonium sulfate gradient. Particle size, encapsulation efficiency,
in vitro
drug release and
in vitro
antibiotic activities were evaluated.
Results
The optimized liposomal formulation has uniform sizes of approximately 100 nm, with encapsulation efficiency of 67.0% (for colistin) and 85.2% (for ciprofloxacin). Incorporation of anionic lipid (DMPG) markedly increased encapsulation efficiency of colistin (from 5.4 to 67.0%); however, the encapsulation efficiency of ciprofloxacin was independent of DMPG ratio. Incorporation of colistin significantly accelerated the release of ciprofloxacin from the DMPG anionic liposomes.
In vitro
release of ciprofloxacin and colistin in the bovine serum for 2 h were above 70 and 50%. The cytotoxicity study using A549 cells showed the liposomal formulation is as non-toxic as the drug solutions. Liposomal formulations of combinations had enhanced
in vitro
antimicrobial activities against multidrug resistant
P. aeruginosa
than the monotherapies.
Conclusions
Liposomal formulations of two synergistic antibiotics was promising against multidrug resistant
P. aeruginosa
infections.
Herein, we describe the first linear-selective hydroarylation reaction of unactivated alkenes and styrenes with aryl boronic acids, which was achieved by introducing a directing group on the alkenes. ...This efficient, scalable reaction serves as a method for modular assembly of structurally diverse alkyl arenes, including γ-aryl butyric acid derivatives, which are widely utilized as chemical building blocks for the synthesis of various drugs and other biologically active compounds.
Increasing evidence indicates that metabolic disorders in offspring can result from the father's diet, but the mechanism remains unclear. In a paternal mouse model given a high-fat diet (HFD), we ...showed that a subset of sperm transfer RNA–derived small RNAs (tsRNAs), mainly from 5’ transfer RNA halves and ranging in size from 30 to 34 nucleotides, exhibited changes in expression profiles and RNA modifications. Injection of sperm tsRNA fractions from HFD males into normal zygotes generated metabolic disorders in the F₁ offspring and altered gene expression of metabolic pathways in early embryos and islets of F₁ offspring, which was unrelated to DNA methylation at CpG-enriched regions. Hence, sperm tsRNAs represent a paternal epigenetic factor that may mediate intergenerational inheritance of diet-induced metabolic disorders.
This paper is concerned with the problem of adaptive fuzzy tracking control via output feedback for a class of uncertain single-input single-output (SISO) strict-feedback nonlinear systems. The ...dynamic feedback strategy begins with an input-driven filter. By utilizing fuzzy logic systems to approximate unknown and desired control input signals directly instead of the unknown nonlinear functions, an output-feedback fuzzy tracking controller is designed via a backstepping approach. It is shown that the proposed fuzzy adaptive output controller can guarantee that all the signals remain bounded and that the tracking error converges to a small neighborhood of the origin. Simulations results are presented to demonstrate the effectiveness of the proposed methods.
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