Modelling and Performance Analysis of the Over-the-Air Computing in Cellular IoT Networks

Ultra-fast wireless data aggregation (WDA) of distributed data has emerged as a critical design challenge in the ultra-densely deployed cellular internet of things network (CITN) due to limited spectral resources. Over-the-air computing (AirComp) has been proposed as an effective solution for ultra-fast WDA by exploiting the superposition property of wireless channels. However, the effect of access radius of access point (AP) on the AirComp performance has not been investigated yet. Therefore, in this work, the mean square error (MSE) performance of AirComp in the ultra-densely deployed CITN is analyzed with the AP access radius. By modelling the spatial locations of internet of things devices as a Poisson point process, the expression of MSE is derived in an analytical form, which is validated by Monte Carlo simulations. Based on the analytical MSE, we investigate the effect of AP access radius on the MSE of AirComp numerically. The results show that there exists an optimal AP access radius for AirComp, which can decrease the MSE by up to 12.7%. It indicates that the AP access radius should be carefully chosen to improve the AirComp performance in the ultra-densely deployed CITN

Dynamic three-dimensional liver volume assessment of liver regeneration in hilar cholangiocarcinoma patients undergoing hemi-hepatectomy

BackgroundFor patients with hilar cholangiocarcinoma (HC) undergoing hemi-hepatectomy, there are controversies regarding the requirement of, indications for, and timing of preoperative biliary drainage (PBD). Dynamic three-dimensional volume reconstruction could effectively evaluate the regeneration of liver after surgery, which may provide assistance for exploring indications for PBD and optimal preoperative bilirubin value. The purpose of this study was to explore the indications for PBD and the optimal preoperative bilirubin value to improve prognosis for HC patients undergoing hemi-hepatectomy.MethodsWe retrospectively analyzed the data of HC patients who underwent hemi-hepatectomy in the First Affiliated Hospital of China Medical University from 2012 to 2023. The liver regeneration rate was calculated using three-dimensional volume reconstruction. We analyzed the factors affecting the liver regeneration rate and occurrence of postoperative liver insufficiency.ResultsThis study involved 83 patients with HC, which were divided into PBD group (n=36) and non-PBD group (n=47). The preoperative bilirubin level may be an independent risk factor affecting the liver regeneration rate (P=0.014) and postoperative liver insufficiency (P=0.016, odds ratio=1.016, β=0.016, 95% CI=1.003–1.029). For patients whose initial bilirubin level was >200 μmol/L (n=45), PBD resulted in better liver regeneration in the early stage (P=0.006) and reduced the incidence of postoperative liver insufficiency [P=0.012, odds ratio=0.144, 95% confidence interval (CI)=0.031–0.657]. The cut-off value of bilirubin was 103.15 μmol/L based on the liver regeneration rate. Patients with a preoperative bilirubin level of ≤103.15 μmol/L shown a better liver regeneration (P<0.01) and lower incidence of postoperative hepatic insufficiency (P=0.011, odds ratio=0.067, 95% CI=0.008–0.537).ConclusionFor HC patients undergoing hemi-hepatectomy whose initial bilirubin level is >200 μmol/L, PBD may result in better liver regeneration and reduce the incidence of postoperative liver insufficiency. Preoperative bilirubin levels ≤103.15 μmol/L maybe recommended for leading to a better liver regeneration and lower incidence of postoperative hepatic insufficiency

Cordyceps cicadae polysaccharides alleviate hyperglycemia by regulating gut microbiota and its mmetabolites in high-fat diet/streptozocin-induced diabetic mice

IntroductionThe polysaccharides found in Cordyceps cicadae (C. cicadae) have received increasing academic attention owing to their wide variety of therapeutic activities.MethodsThis study evaluated the hypoglycemic, antioxidant, and anti-inflammatory effects of polysaccharides from C. cicadae (CH-P). In addition, 16s rDNA sequencing and untargeted metabolomics analysis by liquid chromatography-mass spectrometry (LC-MS) were used to estimate the changes and regulatory relationships between gut microbiota and its metabolites. The fecal microbiota transplantation (FMT) was used to verify the therapeutic effects of microbial remodeling.ResultsThe results showed that CH-P treatment displayed hypoglycemic, antioxidant, and anti-inflammatory effects and alleviated tissue damage induced by diabetes. The CH-P treatment significantly reduced the Firmicutes/Bacteroidetes ratio and increased the abundance of Bacteroides, Odoribacter, Alloprevotella, Parabacteroides, Mucispirillum, and significantly decreased the abundance of Helicobacter and Lactobacillus compared to the diabetic group. The alterations in the metabolic pathways were mostly related to amino acid biosynthesis and metabolic pathways (particularly those involving tryptophan) according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Correlation analysis showed that Bacteroides, Odoribacter, Alloprevotella, Parabacteroides, and Mucispirillum were positively correlated with indole and its derivatives, such as 5-hydroxyindole-3-acetic acid. Indole intervention significantly improved hyperglycemic symptoms and insulin sensitivity, and increased the secretion of glucagon-like peptide-1 (GLP-1) in diabetic mice. FMT reduced blood glucose levels, improved glucose tolerance, and increased insulin sensitivity in diabetic mice. However, FMT did not significantly improve GLP-1 levels.DiscussionThis indicates that C. cicadae polysaccharides alleviate hyperglycemia by regulating the production of metabolites other than indole and its derivatives by gut microbiota. This study provides an important reference for the development of novel natural products

Towards Exascale Computation for Turbomachinery Flows

A state-of-the-art large eddy simulation code has been developed to solve compressible flows in turbomachinery. The code has been engineered with a high degree of scalability, enabling it to effectively leverage the many-core architecture of the new Sunway system. A consistent performance of 115.8 DP-PFLOPs has been achieved on a high-pressure turbine cascade consisting of over 1.69 billion mesh elements and 865 billion Degree of Freedoms (DOFs). By leveraging a high-order unstructured solver and its portability to large heterogeneous parallel systems, we have progressed towards solving the grand challenge problem outlined by NASA, which involves a time-dependent simulation of a complete engine, incorporating all the aerodynamic and heat transfer components.Comment: SC23, November, 2023, Denver, CO., US

Assessing the mechanical responses for anisotropic multi-layered medium under harmonic moving load by Spectral Element Method (SEM)

© 2018 Elsevier Inc. The article is concerned with the mechanical responses of anisotropic multi-layered medium under harmonic moving load. An analytical solution for two-dimensional anisotropic multi-layered medium subjected to harmonic moving load is devoted via Spectral Element Method (SEM), while the anisotropic property is approximated as transverse isotropy. Starting with the constitutive equations of transversely isotropic body and the governing equations of motion based on the loading properties. The analytical spectral elements in the wavenumber domain are obtained according to the principle of wave superposition and Fourier transformation. Then, the spectral global stiffness matrix of the multi-layered medium is derived by assembling the nodded stiffness matrices of all layers depended on the different interlayer conditions between the adjacent layers, i.e. sliding and bonded. The corresponding analytical solutions are achieved by taking the Fourier series and Inverse Fast Fourier Transform (IFFT) algorithm. Finally, some examples are given to validate the accuracy of the proposed analytical solution, and to demonstrate the impact of both anisotropy, top layer thickness, interlayer conditions, and loading properties (velocity and natural frequency) on the mechanical response of the multi-layered medium

Catalytic regioselective acylation of unprotected nucleosides for quick access to COVID and other nucleoside prodrugs

Nucleosides have important therapeutic applications that include antiviral activities against COVID viruses. It is a common strategy to convert one or multiple of the hydroxyl (OH) units in nucleosides to the corresponding ester groups to prepare nucleoside prodrugs for better performance. Due to the presence of multiple OH units in nucleosides, current protocols for access to such ester prodrugs involve multiple steps due to installation and removal of protection groups. Here, we disclose a catalytic strategy that allows for regioselective functionalization of a specific OH unit without the need of protecting other OH groups. The key step in our method is an N-heterocyclic carbene-catalyzed selective acylation of the pentose unit of nucleosides. We demonstrate that commercially launched COVID-19 prodrugs such as molnupiravir can be prepared in concise routes by using our strategy.Ministry of Education (MOE)Nanyang Technological UniversityNational Research Foundation (NRF)Submitted/Accepted versionWe acknowledge the funding support from the National Natural Science Foundation of China (21732002, 21961006, 32172459, 22061007, 22071036), Frontiers Science Center for Asymmetric Synthesis and Medicinal Molecules, Department of Education, Guizhou Province [Qianjiaohe KY number (2020)004], the Science and Technology Department of Guizhou Province (Qiankehejichu-ZK[2021]Key033), Program of Introducing Talents of Discipline to Universities of China (111 Program, D20023) at Guizhou University, Singapore National Research Foundation under its NRF Investigatorship (NRF-NRFI2016-06) and Competitive Research Program (NRF-CRP22-2019-0002); the Singapore Ministry of Education under its MOE AcRF Tier 1 Award (RG7/20, RG5/19), MOE AcRF Tier 2 Award (MOE2019-T2-2-117), and MOE AcRF Tier 3 Award (MOE2018-T3-1-003), and Nanyang Technological University

Quantitative Simulation of Gas Hydrate Formation and Accumulation with 3D Petroleum System Modeling in the Shenhu Area, Northern South China Sea

Gas hydrates have been considered as a new energy that could replace conventional fossil resources in the future because of their high energy density, environmental friendliness, and enormous reserves. To further analyze the potential distribution of gas hydrate stability zones (GHSZ) and the formation of a gas hydrate system in the Shenhu area of the South China Sea (SCS), a 3D petroleum simulation model (PSM) was built from 3D seismic interpretations and all available geological data. Based on the thermal calibration of the 3D model, the evolution of the GHSZ, hydrocarbon generation and migration, and the formation and accumulation of gas hydrates were simulated for the first time in the area. Thermal simulation shows that the methane source of gas hydrate originated from shallow biogenic gas and deep thermogenic gas. Most areas are dominated by shallow biogenic gas, while, only about 3% of the deep thermogenic gas derived from Enping Formation source rock and contributed to the gas hydrate formation within a few areas in the southeast. The thermogenic gas migrated vertically into the GHSZ through connecting faults, mud diapir, and/or gas chimney to form gas hydrate. The source rocks of the Wenchang Formation, a deep thermogenic gas source, began to enter the main hydrocarbon generation window at 28.4 Ma. The Enping source rock began to generate oil from 25 Ma on and gas from 16 Ma on. Since 5.3 Ma, most areas of the source rocks have generated a gas window, and only the shallower parts in the east still in the oil window, which had lasted until now. The shallow biogenic gas source rocks from the Hanjiang, Yuehai, and Wanshan formations generated gas in different periods, respectively. The Qionghai Formation began to generate hydrocarbon from 0.3 Ma and until now. Other results show that the GHSZ developed mainly during the Quaternary and Neogene (Wanshan Formation) and the GHSZ is thicker in the southern area and thinner in the northern part with a positive correlation with water depth. Starting at 11.6 Ma, the GHSZ developed in the Hanjiang Formation in the south of the Shenhu area and gradually expanded to the north to cover most of the study area at 5.3 Ma during the Yuehai Formation. From 1.8 Ma on, the GHSZ covered the entire study area. At the same time, the GHSZ in the Hanjiang Formation disappeared because of the change in temperature and pressure. At present, the GHSZ in the Yuehai Formation has disappeared, while the Quaternary and Wanshan are the two main formations for GHSZ development. The formation and distribution of gas hydrates are fundamentally controlled by the space-time coupling between the hydrocarbon generation and expulsion time and distribution of the GHSZ. The simulation results of gas hydrate accumulation and distribution were verified by drilling results and the matching rate is 84%. This is the first time that 3D simulation was successfully conducted with PSM technology in the Shenhu area and it provides important guidance for gas hydrate study in other areas of the SCS

ROS promote hyper-methylation of NDRG2 promoters in a DNMTS-dependent manner: Contributes to the progression of renal fibrosis

Renal fibrosis is the common histopathological feature of chronic kidney diseases (CKD), and there is increasing evidence that epigenetic regulation is involved in the occurrence and progression of renal fibrosis. N-myc downstream-regulated gene 2 (NDRG2) is significantly down-regulated in renal fibrosis, the mechanism of which remains unclear. Previous studies have confirmed that the inhibition of NDRG2 expression in tumor cells is related to hyper-methylation, mainly regulated by DNA methyltransferases (DNMTS). Herein, we explored the expression of NDRG2 and its epigenetic regulatory mechanism in renal fibrosis. The results showed that the expression of NDRG2 was significantly inhibited in vivo and in vitro, while the overexpression of NDRG2 effectively alleviated renal fibrosis. Meanwhile, we found that the expression of DNMT1/3A/3B was significantly increased in hypoxia-induced HK2 cells and Unilateral Ureteral Obstruction (UUO) mice accompanied by hyper-methylation of the NDGR2 promoter. Methyltransferase inhibitor (5-AZA-dC) corrected the abnormal expression of DNMT1/3A/3B, reduced the methylation level of NDRG2 promoter and restored the expression of NDRG2. The upstream events that mediate changes in NDRG2 methylation were further explored. Reactive oxygen species (ROS) are important epigenetic regulators and have been shown to play a key role in renal injury due to various causes. Accordingly, we further explored whether ROS could induce DNA-epigenetic changes of the expression of NDRG2 and then participated in the development of renal fibrosis. Our results showed that mitochondria-targeted antioxidants (Mito-TEMPO) could reverse the epigenetic inhibition of NDRG2 in a DNMT-sensitive manner, showing strong ability of DNA demethylation, exhibiting epigenetic regulation and anti-fibrosis effects similar to 5-AZA-dC. More importantly, the anti-fibrotic effects of 5-AZA-dC and Mito-TEMPO were eliminated in HK2 cells with NDRG2 knockdown. These findings highlight that targeting ROS-mediated hyper-methylation of NDRG2 promoter is a potentially effective therapeutic strategy for renal fibrosis, which will provide new insights into the treatment of CKD

PD-L1 expression levels in mesenchymal stromal cells predict their therapeutic values for autoimmune hepatitis

Abstract Background Autoimmune hepatitis is a chronic inflammatory hepatic disorder with no effective treatment. Mesenchymal stromal cells (MSCs) have emerged as a promising treatment owing to their unique advantages. However, their heterogeneity is hampering use in clinical applications. Methods Wharton’s jelly derived MSCs (WJ-MSCs) were isolated from 58 human donors using current good manufacturing practice conditions. Gene expression profiles of the WJ-MSCs were analyzed by transcriptome and single-cell RNA-sequencing (scRNA-seq), and subsequent functional differences were assessed. Expression levels of programmed death-ligand 1 (PD-L1) were used as an indicator to screen WJ-MSCs with varied immunomodulation activities and assessed their corresponding therapeutic effects in a mouse model of concanavalin A-induced autoimmune hepatitis. Results The 58 different donor-derived WJ-MSCs were grouped into six gene expression profile clusters. The gene in different clusters displayed obvious variations in cell proliferation, differentiation bias, trophic factor secretion, and immunoregulation. Data of scRNA-seq revealed four distinct WJ-MSCs subpopulations. Notably, the different immunosuppression capacities of WJ-MSCs were positively correlated with PD-L1 expression. WJ-MSCs with high expression of PD-L1 were therapeutically superior to WJ-MSCs with low PD-L1 expression in treating autoimmune hepatitis. Conclusion PD-L1 expression levels of WJ-MSCs could be regarded as an indicator to choose optimal MSCs for treating autoimmune disease. These findings provided novel insights into the quality control of MSCs and will inform improvements in the therapeutic benefits of MSCs