In this paper, a full-angle digital predistortion (DPD) technique is proposed to linearize fifth-generation (5G) millimeter-wave (mmWave) massive multiple-input-multiple-output (mMIMO) transmitters ...with low implementation complexity. It is achieved by compensating the differences of power amplifiers (PAs) in different transmitter chains first and then adopting a common digital block to linearize the whole subarray. Based on this operation, all the transmitter chains can be efficiently linearized simultaneously, providing the merits of full-angle linearization including the main beam and sidelobes. To validate the proposed idea, an mmWave full-digital beam-forming transmitter has been developed, which is operated at the center frequency of 24.75-28.5 GHz to meet the 5G candidate frequency bands. Experimental results show that the proposed method can effectively linearize the mmWave mMIMO transmitter in all directions, which provides a promising linearization solution for 5G mMIMO beam-forming systems.
How coniferous forests evolved in the Northern Hemisphere remains largely unknown. Unlike most groups of organisms that generally follow a latitudinal diversity gradient, most conifer species in the ...Northern Hemisphere are distributed in mountainous areas at middle latitudes. It is of great interest to know whether the midlatitude region has been an evolutionary cradle or museum for conifers and how evolutionary and ecological factors have driven their spatiotemporal evolution. Here, we investigated the macroevolution of
, the largest conifer genus and characteristic of northern temperate coniferous forests, based on nearly complete species sampling. Using 1,662 genes from transcriptome sequences, we reconstructed a robust species phylogeny and reestimated divergence times of global pines. We found that ∼90% of extant pine species originated in the Miocene in sharp contrast to the ancient origin of
, indicating a Neogene rediversification. Surprisingly, species at middle latitudes are much older than those at other latitudes. This finding, coupled with net diversification rate analysis, indicates that the midlatitude region has provided an evolutionary museum for global pines. Analyses of 31 environmental variables, together with a comparison of evolutionary rates of niche and phenotypic traits with a net diversification rate, found that topography played a primary role in pine diversification, and the aridity index was decisive for the niche rate shift. Moreover, fire has forced diversification and adaptive evolution of
Our study highlights the importance of integrating phylogenomic and ecological approaches to address evolution of biological groups at the global scale.
A pandemic of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) infection broke out all over the world; however, epidemiological data and viral shedding in pediatric patients are limited. ...We conducted a retrospective, multicenter study, and followed‐up with all children from the families with SARS‐CoV‐2 infected members in Zhejiang Province, China. All infections were confirmed by testing the SARS‐CoV‐2 RNA with real‐time reverse transcription PCR method, and epidemiological data between children and adults in the same families were compared. Effect of antiviral therapy was evaluated observationally and fecal‐viral excretion times among groups with different antiviral regiments were compared with Kaplan‐Meier plot. By 29 February 2020, 1298 cases from 883 families were confirmed with SARS‐CoV‐2 infection and 314 of which were families with children. Incidence of infection in child close contacts was significantly lower than that in adult contacts (13.2% vs 21.2%). The mean age of 43 pediatric cases was 8.2 years and mean incubation period was 9.1 days. Forty (93.0%) were family clustering. Thirty‐three children had coronavirus disease 2019 (20 pneumonia) with mild symptoms and 10 were asymptomatic. Fecal SARS‐CoV‐2 RNA detection was positive in 91.4% (32/35) cases and some children had viral excretion time over 70 days. Viral clearance time was not different among the groups treated with different antiviral regiments. No subsequent infection was observed in family contacts of fecal‐viral‐excreting children. Children have lower susceptibility of SARS‐CoV‐2 infection, longer incubation, and fecal‐viral excretion time. Positive results of fecal SARS‐CoV‐2 RNA detection were not used as indication for hospitalization or quarantine.
Highlights
Children had lower susceptibility for SARS‐CoV‐2 infection than adults.
Children had longer incubation period and fecal viral excretion time after infected by SARS‐CoV‐2.
Viral clearance time was not different among the groups treated with different antiviral regiments.
Children had milder clinical symptoms, better clinical outcome, and more common fecal viral excretion.
Positive results of fecal SARS‐CoV‐2 RNA detection are not used as indication for hospitalization or quarantine.
Fractals are fascinating, not only for their aesthetic appeal but also for allowing the investigation of physical properties in non-integer dimensions. In these unconventional systems, many intrinsic ...features might come into play, including the fractal dimension and the fractal geometry. Despite abundant theoretical studies, experiments in fractal networks remain elusive. Here we experimentally investigate quantum transport in fractal networks by performing continuous-time quantum walks in fractal photonic lattices. We unveil the transport properties through the photon evolution patterns, the mean square displacement and the Pólya number. Contrarily to classical fractals, we observe anomalous transport governed solely by the fractal dimension. In addition, the critical point at which there is a transition from normal to anomalous transport depends on the fractal geometry. Our experiment allows the verification of physical laws in a quantitative manner and reveals the transport dynamics in great detail, thus opening a path to the understanding of more complex quantum phenomena governed by fractality.Quantum transport in fractal networks is experimentally investigated by performing continuous-time quantum walks in fractal photonic lattices. Contrarily to classical fractals, anomalous transport governed solely by the fractal dimension is observed.
Control of TiO2 crystal facets has attracted enormous interest due to the fascinating shape-dependent photocatalytic activity of this material. In this work, the effect of the ratio of {001} and ...{101} facets on the photocatalytic CO2-reduction performance of anatase TiO2 is reported. A new “surface heterojunction” concept is proposed on the basis of the density functional theory (DFT) calculations to explain the difference in the photocatalytic activity of TiO2 with coexposed {001} and {101} facets.
Endothelial cells are important constituents of blood vessels that play critical roles in cardiovascular homeostasis by regulating blood fluidity and fibrinolysis, vascular tone, angiogenesis, ...monocyte/leukocyte adhesion, and platelet aggregation. The normal vascular endothelium is taken as a gatekeeper of cardiovascular health, whereas abnormality of vascular endothelium is a major contributor to a plethora of cardiovascular ailments, such as atherosclerosis, aging, hypertension, obesity, and diabetes. Endothelial dysfunction is characterized by imbalanced vasodilation and vasoconstriction, elevated reactive oxygen species (ROS), and proinflammatory factors, as well as deficiency of nitric oxide (NO) bioavailability. The occurrence of endothelial dysfunction disrupts the endothelial barrier permeability that is a part of inflammatory response in the development of cardiovascular diseases. As such, abrogation of endothelial cell activation/inflammation is of clinical relevance. Recently, hydrogen sulfide (H
S), an entry as a gasotransmitter, exerts diverse biological effects through acting on various targeted signaling pathways. Within the cardiovascular system, the formation of H
S is detected in smooth muscle cells, vascular endothelial cells, and cardiomyocytes. Disrupted H
S bioavailability is postulated to be a new indicator for endothelial cell inflammation and its associated endothelial dysfunction. In this review, we will summarize recent advances about the roles of H
S in endothelial cell homeostasis, especially under pathological conditions, and discuss its putative therapeutic applications in endothelial inflammation-associated cardiovascular disorders.
Catenanes are intriguing molecular architectures with unique properties. Herein, we report the cellular synthesis of protein catenanes containing folded structural domains, aided by synergy between ...p53 dimerization and SpyTag/SpyCatcher chemistry. Concatenation of green fluorescent protein (GFP) was shown to increase chemical stability without disrupting the fluorescence properties, and concatenated dihydrofolate reductase (DHFR) exhibited a melting temperature around 4 °C higher and catalytic activity around 27 % higher than the wild‐type DHFR and the cyclic/linear controls. Catenation also confers considerable proteolytic resistance on DHFR. The results suggest that catenation could enhance both the stability and activity of folded proteins, thus making topology engineering an attractive approach for tailoring protein properties without varying their native sequences.
We go together: Cellular synthesis of protein catenanes containing folded structural domains was effectively achieved by using p53 dimerization and SpyTag/SpyCatcher chemistry. Catenation was found to endow the purified proteins of interest (POIs) with several valuable attributes, including enhanced thermal stability, increased proteolytic resistance, and enhanced enzymatic activity.
Of the approximately 1,200 plant virus species that have been described to date, nearly one-third are single-stranded DNA (ssDNA) viruses, and all are transmitted by insect vectors. However, most ...studies of vector transmission of plant viruses have focused on RNA viruses. All known plant ssDNA viruses belong to two economically important families,
and
, and in recent years, there have been increased efforts to understand whether they have evolved similar relationships with their respective insect vectors. This review describes the current understanding of ssDNA virus-vector interactions, including how these viruses cross insect vector cellular barriers, the responses of vectors to virus circulation, the possible existence of viral replication within insect vectors, and the three-way virus-vector-plant interactions. Despite recent breakthroughs in our understanding of these viruses, many aspects of plant ssDNA virus transmission remain elusive. More effort is needed to identify insect proteins that mediate the transmission of plant ssDNA viruses and to understand the complex virus-insect-plant three-way interactions in the field during natural infection.
Traditional electronic skin (e‐skin), due to the lack of human‐brain‐like thinking and judging capability, is powerless to accelerate the pace to the intelligent era. Herein, artificial intelligence ...(AI)‐motivated full‐skin bionic (FSB) e‐skin consisting of the structures of human vellus hair, epidermis–dermis–hypodermis, is proposed. Benefiting from the double interlocked layered microcone structure and supercapacitive iontronic effect, the FSB e‐skin exhibits ultrahigh sensitivity of 8053.1 kPa−1 (<1 kPa), linear sensitivity of 3103.5 kPa−1 (1–34 kPa), and fast response/recovery time of <5.6 ms. In addition, it can realize the evolution from tactile perception to advanced intelligent tactile cognition after being equipped with a “brain”. First, static/dynamic contactless tactile perception is achieved based on the triboelectric effect of the vellus hair bionics. Second, the supercapacitive iontronic effect based structural bionics of the epidermis–dermis–hypodermis and a five‐layer multilayer perception (MLP) enable the general intelligent tactile cognition of gesture cognition and robot interaction. Most importantly, by making full use of the FSB e‐skin with a six‐layer MLP neural network, an advanced intelligent material cognition system is developed for real‐time cognition of the object material species and locations via one contact, which surpasses the capability of humans.
An artificial intelligence (AI)‐motivated full‐skin bionic (FSB) e‐skin based on vertically integrated triboelectric e‐skin and supercapacitive iontronic e‐skin is proposed through the mimicry of skin structures including human vellus hair, epidermis–dermis–hypodermis. Assisted by the AI‐motivated “brain,” the proposed FSB e‐skin can promote the function of tactile perception to advanced intelligent tactile cognition.
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