Multifunctional Film Assembled from N‑Doped Carbon Nanofiber with Co–N_(4)–O Single Atoms for Highly Efficient Electromagnetic Energy Attenuation

Single-atom materials have demonstrated attractive physicochemical characteristics.However,understanding the relationships between the coordination environment of single atoms and their properties at the atomic level remains a considerable challenge.Herein,a facile waterassisted carbonization approach is developed to fabricate well-defined asymmetrically coordinated Co–N_(4)–O sites on biomass-derived carbon nanofiber(Co–N_(4)–O/NCF)for electromagnetic wave(EMW)absorption.In such nanofiber,one atomically dispersed Co site is coordinated with four N atoms in the graphene basal plane and one oxygen atom in the axial direction.In-depth experimental and theoretical studies reveal that the axial Co–O coordination breaks the charge distribution symmetry in the planar porphyrin-like Co–N_(4) structure,leading to significantly enhanced dielectric polarization loss relevant to the planar Co–N_(4) sites.Importantly,the film based on Co–N_(4)–O/NCF exhibits light weight,flexibility,excellent mechanical properties,great thermal insulating feature,and excellent EMW absorption with a reflection loss of−45.82 dB along with an effective absorption bandwidth of 4.8 GHz.The findings of this work offer insight into the relationships between the single-atom coordination environment and the dielectric performance,and the proposed strategy can be extended toward the engineering of asymmetrically coordinated single atoms for various applications.

Identification of the Intrinsic Dielectric Properties of Metal Single Atoms for Electromagnetic Wave Absorption

Atomically dispersed metals on N-doped carbon supports(M-N_(xCs)) have great potential applications in various fields.However,a precise understanding of the definitive relationship between the configuration of metal single atoms and the dielectric loss properties of M-N_(xCs) at the atomic-level is still lacking.Herein,we report a general approach to synthesize a series of three-dimensional(3D)honeycomb-like M-N_xC(M=Mn,Fe,Co,Cu,or Ni) containing metal single atoms.Experimental results indicate that 3D M-N_(xCs) exhibit a greatly enhanced dielectric loss compared with that of the NC matrix.Theoretical calculations demonstrate that the density of states of the d orbitals near the Fermi level is significantly increased and additional electrical dipoles are induced due to the destruction of the symmetry of the local microstructure,which enhances conductive loss and dipolar polarization loss of 3D M-N_(xCs),respectively.Consequently,these 3D M-N_(xCs) exhibit excellent electromagnetic wave absorption properties,outperforming the most commonly reported absorbers.This study systematically explains the mechanism of dielectric loss at the atomic level for the first time and is of significance to the rational design of high-efficiency electromagnetic wave absorbing materials containing metal single atoms.

Nitrogen and Boron Co-Doped Carbon Nanotubes Embedded with Nickel Nanoparticles as Highly Efficient Electromagnetic Wave Absorbing Materials

Due to the limitations of impedance matching and attenuation matching,carbon nanotubes(CNTs)employed alone have a weak capacity to attenuate electromagnetic wave(EMW)energy.In this work,B and N co-doped CNTs with embedded Ni nanoparticles(Ni@BNCNTs)are fabricated via an in situ doping method.Compared with a sample without B doping,Ni@BNCNTs demonstrate a superior EMW absorption performance,with all minimum reflection loss values below−20 dB,even at a matching thickness of 1.5 mm.The experimental and theoretical calculation results demonstrate that B doping increases conduction and polarization relaxation losses,as well as the impedance matching characteristic,which is responsible for the enhanced EMW absorption performance of Ni@BNCNTs.

Single-cell RNA Sequencing Reveals Thoracolumbar Vertebra Heterogeneity and Rib-genesis in Pigs

Development of thoracolumbar vertebra(TLV)and rib primordium(RP)is a common evolutionary feature across vertebrates,although whole-organism analysis of the expression dynamics of TLV-and RP-related genes has been lacking.Here,we investigated the single-cell transcriptome landscape of thoracic vertebra(TV),lumbar vertebra(LV),and RP cells from a pig embryo at 27 days post-fertilization(dpf)and identified six cell types with distinct gene expression signatures.In-depth dissection of the gene expression dynamics and RNA velocity revealed a coupled process of osteogenesis and angiogenesis during TLV and RP development.Further analysis of cell type-specific and strand-specific expression uncovered the extremely high level of HOXA103′-UTR sequence specific to osteoblasts of LV cells,which may function as anti-HOXA10-antisense by counteracting the HOXA10-antisense effect to determine TLV transition.Thus,this work provides a valuable resource for understanding embryonic osteogenesis and angiogenesis underlying vertebrate TLV and RP development at the cell type-specific resolution,which serves as a comprehensive view on the transcriptional profile of animal embryo development.

A Positive Correlation between Elevated Altitude and Frequency of Mutant Alleles at the EPAS1 and HBB Loci in Chinese Indigenous Dogs

Hypoxia represents one of the most extreme environmental conditions for both human beings and animals living at high al- titudes （Zhao et al., 2009）. Over the past few years, great attention has been focused on the genetic bases of adaption to high-altitude environments （Bigham et al., 2010; Simonson et al., 2010）. The domestic dog （Canisfamiliaris） is the first animal that developed an intimate relationship with human beings. Dogs migrated with human beings and have adapted to variety of ecological niches （Savolainen et al., 2002）. Our previous research revealed parallel evolution and convergent evolution in the adaptation of dogs and humans to the high-altitude environment of the Tibetan plateau （Wang et al., 2013, 2014）, suggesting that exploring the adaption of domestic dogs to high-altitude hypoxia is an interesting and important question.

High performance work systems and corporate performance： the influence of entrepreneurial orientation and organizational learning

This study investigates the functioning mechanisms of how high performance work systems （HPWS） affect organizational performance. We propose that （HPWS） can positively affect organizational performance through the mediating role of entrepreneurial orientation. An organization with high performance work systems can perform better if it enjoys high level of organizational learning. We design and administer a survey questionnaire to high-level executives or founders of companies from manufacturing and service industries and receive 176 valid responses. The results of the empirical data indicate that the relationship between high performance work systems and corporate performance is more positive when organizational learning is stronger. Entrepreneurial orientation partially mediates the relationship between high performance work systems and organizational performance. This study opens new research avenues by extending and incorporating explanations and predictions of HPWS and entrepreneurial orientation, two areas that largely have been considered independently of each other. Implications for practice and directions for future research are provided.

Differentiation and pricing power of online retailers

This study aims to contribute to marketing theory by applying monopolistic competition theory to investigate how differentiation affects online retailers7 pricing power. We examine the intermediary effect of customer loyalty on the relationship between differentiation and pricing power of online retailers. We assume that customers have different preferences for the differentiated characteristics of online retailers, and thus different degrees of willingness to pay premiums, which gives online retailers pricing power. Structural equation modeling (SEM) is employed to test the hypothesized relati on ships between differentiation, customer loyalty, and pricing power. The statistical results of the empirical data indicate that some of the differentiation characteristics of online retailers can cultivate their pricing power indirectly. Logistics quality followed by commodity assortment and transaction security produces profound effects on the buildup of pricing power with customer loyalty as an intermediary factor. Results further reveal that commodity quality is positively related to pricing power. This study expands the definition of differentiation by combining corporate strategic positioning with commodity pricing. Implications for practice and di recti ons for future research are provided.

Develop potential multi-target drugs by self-assembly of quercetin with amino acids and metal ion to achieve significant efficacy in anti-Alzheimer’s disease

Exploring multi-target drugs(MTDs)is a prevalent method against Alzheimer’s disease(AD).However,the current developed MTDs based on the“framework combination”technique or using flavonoids have not realized better healing effects owing to a complex metabolic process and low bioavailability.Here,we propose an alternative strategy to develop self-assembled nanoparticles(NPs)as MTDs using 9-fluorenylmethyloxycarbonyl-tryptophan(Fmoc-Trp),quercetin(Que),and Fe^(2+)as building blocks through coordination and electrostatic interaction to generate Fmoc-Trp-Fe^(2+)-Que(FTFQ)NPs.Whether in cell or in vivo,FTFQ NPs exhibited considerable biocompatibility attributing to the inherent biological affinity of assembly units.By combining the advantages of assemble approach and nanostructures,the obtained FTFQ NPs greatly enhanced the bioavailability of Que and displayed synergistic therapeutic effects through reducing Aβaggregation in direct/indirect means and eliminating the toxicity induced by ROS and Aβoligomer/fibrils.Furthermore,FTFQ NPs could obviously restore the AD zebrafish’s mobility and stimulus response ability.More importantly,developing self-assembly NPs as MTDs could be an efficient and general method to promote other novel MTDs by extending the assemble units to other drugs,peptides,and metal ions.Based on above benefits,these self-assembled NPs could be as potential MTDs and show great promising application in AD treatment.

Risk Control of Pension Fund Management in China

Based on an analysis of China ＇s current pension system, the present paper indicates that risk control of pension fund management is a serious policy challenge for the Chinese Government. Although some reform efforts have been made, there are still serious institutional and capital market risks that are difficult to overcome but are key in the success of China＇s pension reform. To ensure a smooth transition in pension reform, China not only needs to build a better institutional framework and facilitate capital market development, but also raise the risk awareness of individual pensioners.

In teg rati ng organizati on al lear ning with high-performance work system and entrepreneurial orientation: a moderated mediation framework

This study proposes a moderated mediation model to investigate the relationship between organizational learning and firm performance. We argue that entrepreneurial orientation mediates the positive effect of organizational learning on firm performance. Furthermore, the relationship between organizational learning and entrepreneurial orientation is strengthened when firms employ a higher level of high-performance work system. Hypotheses are supported by data from 181 firms operating in the manufacturing and service industries in China. Statistical results further reveal that a high-performance work system has different moderating effects on exploitative learning and exploratory learning. This research extends our understanding of organizational learning theory, entrepreneurship and human resource management literature by cross-fertilizing constructs in these fields with empirical evidence.