147 research outputs found
How to Extend 3D GBSM to Integrated Sensing and Communication Channel with Sharing Feature?
Integrated Sensing and Communication (ISAC) is a promising technology in 6G
systems. The existing 3D Geometry-Based Stochastic Model (GBSM), as
standardized for 5G systems, addresses solely communication channels and lacks
consideration of the integration with sensing channel. Therefore, this letter
extends 3D GBSM to support ISAC research, with a particular focus on capturing
the sharing feature of both channels, including shared scatterers, clusters,
paths, and similar propagation param-eters, which have been experimentally
verified in the literature. The proposed approach can be summarized as follows:
Firstly, an ISAC channel model is proposed, where shared and non-shared
components are superimposed for both communication and sensing. Secondly,
sensing channel is characterized as a cascade of TX-target, radar cross
section, and target-RX, with the introduction of a novel parameter S for shared
target extraction. Finally, an ISAC channel implementation framework is
proposed, allowing flexible configuration of sharing feature and the joint
generation of communication and sensing channels. The proposed ISAC channel
model can be compatible with the 3GPP standards and offers promising support
for ISAC technology evaluation
Structures and growth pathways of AunCln+3-(n≤7) cluster anions
Gold chloride clusters play an important role in catalysis and materials chemistry. Due to the diversity of their species and isomers, there is still a dearth of structural studies at the molecular level. In this work, anions of AunCln+3- and AunCln+5- (n = 2–4) clusters were obtained by laser desorption/ionization mass spectrometry (LDI MS), and the most stable isomers of AunCln+3- were determined after a thorough search and optimization at the TPSSh/aug-cc-pVTZ/ECP60MDF level. The results indicate that all isomers with the lowest energy have a planar zigzag skeleton. In each species, there is one Au(III) atom at the edge connected with four Cl atoms, which sets it from the other Au(I) atoms. Four growth pathways for AunCln+3- (n = 2–7) clusters are proposed (labelled R1, R2, R3 and R4). They are all associated with an aurophilic contact and are exothermic. The binding energies tend to stabilize at ~ −41 kcal/mol when the size of the cluster increases in all pathways. The pathway R1, which connects all the most stable isomers of the respective clusters, is characterized by cluster growth due to aurophilic interactions at the terminal atom of Au(I) in the zigzag chains. In the pathway of R4 involving Au-Au bonding in its initial structures (n ≤ 3), the distance between intermediate gold atoms grows with cluster size, ultimately resulting in the transfer of the intermediate Au-Au bonding into aurophilic interaction. The size effect on the structure and aurophilic interactions of these clusters will be better understood based on these discoveries, potentially providing new insights into the active but elusive chemical species involved in the corresponding catalytic reactions or nanoparticle synthesis processes
Elevated Monocyte to High-density Lipoprotein Ratio Is a Risk Factor for New-onset Atrial Fibrillation after Off-pump Coronary Revascularization
Atrial fibrillation (AF) is a common complication of coronary revascularization. Currently, the mechanisms of postoperative AF are unclear. This study was aimed at investigating the risk factors for new-onset AF (NOAF) after coronary revascularization and exploring the early warning effects of clinical inflammatory markers. A retrospective analysis was conducted on 293 patients with unstable angina pectoris who underwent coronary artery revascularization in Beijing Chao-Yang Hospital, Capital Medical University, between April 2018 and June 2021, including 224 patients who underwent coronary artery bypass grafting and 69 patients who underwent one-step hybrid coronary revascularization. Baseline data, clinical data, blood indicators and AF episodes within 7 days after the surgery were collected. Participants were divided into two groups according to whether AF occurred, and the data were analyzed between groups. In addition, multivariate logistic regression was used to explore the independent risk factors for developing AF post coronary revascularization. Aging, a larger left atrial inferior-superior diameter, use of an intra-aortic balloon pump, a greater blood volume transfused during perioperative period and a higher monocyte to high-density lipoprotein ratios on postoperative day 1 were independent risk factors for NOAF after coronary artery surgery
Toxin-antitoxin system gene mutations driving Mycobacterium tuberculosis transmission revealed by whole genome sequencing
BackgroundThe toxin-antitoxin (TA) system plays a vital role in the virulence and pathogenicity of Mycobacterium tuberculosis (M. tuberculosis). However, the regulatory mechanisms and the impact of gene mutations on M. tuberculosis transmission remain poorly understood.ObjectiveTo investigate the influence of gene mutations in the toxin-antitoxin system on M. tuberculosis transmission dynamics.MethodWe performed whole-genome sequencing on the analyzed strains of M. tuberculosis. The genes associated with the toxin-antitoxin system were obtained from the National Center for Biotechnology Information (NCBI) Gene database. Mutations correlating with enhanced transmission within the genes were identified by using random forest, gradient boosting decision tree, and generalized linear mixed models.ResultsA total of 13,518 M. tuberculosis isolates were analyzed, with 42.29% (n = 5,717) found to be part of genomic clusters. Lineage 4 accounted for the majority of isolates (n = 6488, 48%), followed by lineage 2 (n = 5133, 37.97%). 23 single nucleotide polymorphisms (SNPs) showed a positive correlation with clustering, including vapB1 G34A, vapB24 A76C, vapB2 T171C, mazF2 C85T, mazE2 G104A, vapB31 T112C, relB T226A, vapB11 C54T, mazE5 T344C, vapB14 A29G, parE1 (C103T, C88T), and parD1 C134T. Six SNPs, including vapB6 A29C, vapB31 T112C, parD1 C134T, vapB37 G205C, Rv2653c A80C, and vapB22 C167T, were associated with transmission clades across different countries. Notably, our findings highlighted the positive association of vapB6 A29C, vapB31 T112C, parD1 C134T, vapB37 G205C, vapB19 C188T, and Rv2653c A80C with transmission clades across diverse regions. Furthermore, our analysis identified 32 SNPs that exhibited significant associations with clade size.ConclusionOur study presents potential associations between mutations in genes related to the toxin-antitoxin system and the transmission dynamics of M. tuberculosis. However, it is important to acknowledge the presence of confounding factors and limitations in our study. Further research is required to establish causation and assess the functional significance of these mutations. These findings provide a foundation for future investigations and the formulation of strategies aimed at controlling TB transmission
Four novel variants identified in primary hyperoxaluria and genotypic and phenotypic analysis in 21 Chinese patients
Background: Primary hyperoxaluria (PH) is a rare genetic disorder characterized by excessive accumulation of oxalate in plasma and urine, resulting in various phenotypes due to allelic and clinical heterogeneity. This study aimed to analyze the genotype of 21 Chinese patients with primary hyperoxaluria (PH) and explore their correlations between genotype and phenotype.Methods: Combined with clinical phenotypic and genetic analysis, we identified 21 PH patients from highly suspected Chinese patients. The clinical, biochemical, and genetic data of the 21 patients were subsequently reviewed.Results: We reported 21 cases of PH in China, including 12 cases of PH1, 3 cases of PH2 and 6 cases of PH3, and identified 2 novel variants (c.632T > G and c.823_824del) in AGXT gene and 2 novel variants (c.258_272del and c.866-34_866-8del) in GRHPR gene, respectively. A possible PH3 hotspot variant c.769T > G was identified for the first time. In addition, patients with PH1 showed higher levels of creatinine and lower eGFR than those with PH2 and PH3. In PH1, patients with severe variants in both alleles had significantly higher creatinine and lower eGFR than other patients. Delayed diagnosis still existed in some late-onset patients. Of all cases, 6 had reached to end-stage kidney disease (ESKD) at diagnosis with systemic oxalosis. Five patients were on dialysis and three had undergone kidney or liver transplants. Notably, four patients showed a favorable therapeutic response to vitamin B6, and c.823_824dup and c.145A > C may be identified as potentially vitamin B6-sensitive genotypes.Conclusion: In brief, our study identified 4 novel variants and extended the variant spectrum of PH in the Chinese population. The clinical phenotype was characterized by large heterogeneity, which may be determined by genotype and a variety of other factors. We first reported two variants that may be sensitive to vitamin B6 therapy in Chinese population, providing valuable references for clinical treatment. In addition, early screening and prognosis of PH should be given more attention. We propose to establish a large-scale registration system for rare genetic diseases in China and call for more attention on rare kidney genetic diseases
Channel Measurement, Modeling, and Simulation for 6G: A Survey and Tutorial
The sixth generation (6G) mobile communications have attracted substantial
attention in the global research community of information and communication
technologies (ICT). 6G systems are expected to support not only extended 5G
usage scenarios, but also new usage scenarios, such as integrated sensing and
communication (ISAC), integrated artificial intelligence (AI) and
communication, and communication and ubiquitous connectivity. To realize this
goal, channel characteristics must be comprehensively studied and properly
exploited, so as to promote the design, standardization, and optimization of 6G
systems. In this paper, we first summarize the requirements and challenges in
6G channel research. Our focus is on channels for five promising technologies
enabling 6G, including terahertz (THz), extreme MIMO (E-MIMO), ISAC,
reconfigurable intelligent surface (RIS), and space-air-ground integrated
network (SAGIN). Then, a survey of the progress of the 6G channel research
regarding the above five promising technologies is presented in terms of the
latest measurement campaigns, new characteristics, modeling methods, and
research prospects. Moreover, a tutorial on the 6G channel simulations is
presented. We introduce the BUPTCMG- 6G, a 6G link-level channel simulator,
developed based on the ITU/3GPP 3D geometry-based stochastic model (GBSM)
methodology. The simulator supports the channel simulation of the
aforementioned 6G potential technologies. To facilitate the use of the
simulator, the tutorial encompasses the design framework, user guidelines, and
application examples. This paper offers in-depth, hands-on insights into the
best practices of channel measurements, modeling, and simulations for the
evaluation of 6G technologies, the development of 6G standards, and the
implementation and optimization of 6G systems.Comment: 41 pages,52 figure
Where Do I Come From? Metaphors in Sex Education Picture Books for Young Children in China
This study examines the types of verbal, pictorial, and multimodal metaphors in the genre of sex education picture books for young children in Mainland China. Although being an educational discourse genre that is essentially concerned with transmitting scientific facts, sex education picture books employ a range of metaphors that categorize and construe the biological knowledge of human reproduction in a way that not only facilitates young children’s understanding of scientific concepts but also instills in them particular values and moralities that are socioculturally conditioned. An examination of the source domains from which the metaphors are drawn and the target domains onto which the metaphors are mapped reveals three types of metaphor, namely, personification, domestication, and cross-experience metaphors. The analysis of seven sex education picture books for pre-school children suggests that these types of metaphor are used purposefully for addressing pedagogical as well as ideological concerns in the introduction of sex-related knowledge in Mainland China
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