MIMO Channel Modelling and Performance Evaluations

The demand on wireless networks with high throughput has grown heavily because of the increasing usage of data services. One of the key technologies to meet this requirement is the multiple-input multiple-output (MIMO) communication system, which improves the spectrum effciency without too much investment on the infrastructure and new frequency spectrum. In this theis, a new MIMO channel model is developed that is specifc to real scenarios. This kind of channel models is more suitable for network planning tools because it takes the environment details into account. The frst step of this work is a review on the state-of-the-art MIMO channel modelling and radio propagation modelling studies. It is then followed by a comparison of two propagation models that use different algorithms, i.e. ray optical and partial flow. The comparison leads to a decision that ray optical method is used for MIMO channel modelling in this thesis. After that, a spatial channel model based on a deterministic ray optical propagation model is proposed. The fnal MIMO channel model takes the polarisation and the Doppler effect in to account so that it can be used for MIMO systems with polarised antennas and moving objects as well. The model is used in a system level simulator and then validated in an indoor offce building using measurement data. It is concluded from this thesis that the chosen propagation model can be used for MIMO channel modelling, and the proposed MIMO channel model based on it is accurate and can be used for MIMO system design

On optimizing subspaces for face recognition

Abstract We propose a subspace learning algorithm for face recognition by directly optimizing recognition performance scores

Saccharin induced liver inflammation in mice by altering the gut microbiota and its metabolic functions

Maintaining the balance of the gut microbiota and its metabolic functions is vital for human health, however, this balance can be disrupted by various external factors including food additives. A range of food and beverages are sweetened by saccharin, which is generally considered to be safe despite controversial debates. However, recent studies indicated that saccharin perturbed the gut microbiota. Inflammation is frequently associated with disruptions of the gut microbiota. The aim of this study is to investigate the relationship between host inflammation and perturbed gut microbiome by saccharin. C57BL/6J male mice were treated with saccharin in drinking water for six months. Q-PCR was used to detect inflammatory markers in mouse liver, while 16S rRNA gene sequencing and metabolomics were used to reveal changes of the gut microbiota and its metabolomic profiles. Elevated expression of pro-inflammatory iNOS and TNF-α in liver indicated that saccharin induced inflammation in mice. The altered gut bacterial genera, enriched orthologs of pathogen-associated molecular patterns, such as LPS and bacterial toxins, in concert with increased pro-inflammatory metabolites suggested that the saccharin-induced liver inflammation could be associated with the perturbation of the gut microbiota and its metabolic functions

Manganese-induced sex-specific gut microbiome perturbations in C57BL/6 mice

Overexposure to manganese (Mn) leads to toxic effects, such as promoting the development of Parkinson’s-like neurological disorders. The gut microbiome is deeply involved in immune development, host metabolism, and xenobiotics biotransformation, and significantly influences central nervous system (CNS) via the gut-brain axis, i.e. the biochemical signaling between the gastrointestinal tract and the CNS. However, it remains unclear whether Mn can affect the gut microbiome and its metabolic functions, particularly those linked to neurotoxicity. In addition, sex-specific effects of Mn have been reported, with no mechanism being identified yet. Recently, we have shown that the gut microbiome is largely different between males and females, raising the possibility that differential gut microbiome responses may contribute to sex-selective toxicity of Mn. Here, we applied high-throughput sequencing and gas chromatography–mass spectrometry (GC-MS) metabolomics to explore how Mn2+ exposure affects the gut microbiome and its metabolism in C57BL/6 mice. Mn2+ exposure perturbed the gut bacterial compositions, functional genes and fecal metabolomes in a highly sex-specific manner. In particular, bacterial genes and/or key metabolites of neurotransmitter synthesis and pro-inflammatory mediators are significantly altered by Mn2+ exposure, which can potentially affect chemical signaling of gut-brain interactions. Likewise, functional genes involved in iron homeostasis, flagellar motility, quorum sensing, and Mn transportation/oxidation are also widely changed by Mn2+ exposure. Taken together, this study has demonstrated that Mn2+ exposure perturbs the gut microbiome and its metabolic functions, which highlights the potential role of the gut microbiome in Mn2+ toxicity, particularly its sex-specific toxic effects

Multi-Omics Reveals that Lead Exposure Disturbs Gut Microbiome Development, Key Metabolites, and Metabolic Pathways

Lead exposure remains a global public health issue, and the recent Flint water crisis has renewed public concern about lead toxicity. The toxicity of lead has been well established in a variety of systems and organs. The gut microbiome has been shown to be highly involved in many critical physiological processes, including food digestion, immune system development, and metabolic homeostasis. However, despite the key role of the gut microbiome in human health, the functional impact of lead exposure on the gut microbiome has not been studied. The aim of this study is to define gut microbiome toxicity induced by lead exposure in C57BL/6 mice using multiomics approaches, including 16S rRNA sequencing, whole genome metagenomics sequencing, and gas chromatography-mass spectrometry (GC-MS) metabolomics. 16S rRNA sequencing revealed that lead exposure altered the gut microbiome trajectory and phylogenetic diversity. Metagenomics sequencing and metabolomics profiling showed that numerous metabolic pathways, including vitamin E, bile acids, nitrogen metabolism, energy metabolism, oxidative stress, and the defense/detoxification mechanism, were significantly disturbed by lead exposure. These perturbed molecules and pathways may have important implications for lead toxicity in the host. Taken together, these results demonstrated that lead exposure not only altered the gut microbiome community structures/diversity but also greatly affected metabolic functions, leading to gut microbiome toxicity

Serum Metabolomic Profiling of Piglets Infected with Virulent Classical Swine Fever Virus

Citation: Gong, W. J., Jia, J. J., Zhang, B. K., Mi, S. J., Zhang, L., Xie, X. M., . . . Tu, C. C. (2017). Serum Metabolomic Profiling of Piglets Infected with Virulent Classical Swine Fever Virus. Frontiers in Microbiology, 8, 14. doi:10.3389/fmicb.2017.00731Classical swine fever (CSF) is a highly contagious swine infectious disease and causes significant economic losses for the pig industry worldwide. The objective of this study was to determine whether small molecule metabolites contribute to the pathogenesis of CSF. Birefly, serum metabolomics of CSFV Shimen strain-infected piglets were analyzed by ultraperformance liquid chromatography/electrospray ionization time-of-flight mass spectrometry (UPLC/ESI-Q-TOF/MS) in combination with multivariate statistical analysis. In CSFV-infected piglets at days 3 and 7 post-infection changes were found in metabolites associated with several key metabolic pathways, including tryptophan catabolism and the kynurenine pathway, phenylalanine metabolism, fatty acid and lipid metabolism, the tricarboxylic acid and urea cycles, branched-chain amino acid metabolism, and nucleotide metabolism. Several pathways involved in energy metabolism including fatty acid biosynthesis and beta-oxidation, branched-chain amino acid metabolism, and the tricarboxylic acid cycle were significantly inhibited. Changes were also observed in several metabolites exclusively associated with gut microbiota. The metabolomic profiles indicate that CSFV-host gut microbiome interactions play a role in the development of CSF

Automatic facial landmark labeling with minimal supervision.

Abstract Landmark labeling of training images is essential for many learning tasks in computer vision, such as object detection, tracking, an

Analysis of Face Stability during Excavation of Double-O-Tube Shield Tunnel

This paper focuses on the face stability analysis of Double-O-Tube shield tunnel. This kind of analysis is significant to ensure the safety of workers and reduce the influence on the surrounding environment. The key point of the stability analysis is to determine the supporting pressure applied to the face by the shield. A collapse failure will occur when the supporting pressure is not sufficient to prevent the movement of the soil mass towards the tunnel. A three-dimensional collapse failure mechanism was presented in this paper. Based on the mechanism of a single circular shield tunnel, the mechanism of Double-O-Tube shield tunnel was established by using the fact that both of the mechanisms are symmetrical. Then by means of the kinematic theorem of limit analysis, the numerical results were obtained, and a design chart was provided. The finite difference software FLAC3D was applied to investigate the face failure mechanism of DOT shield tunnel established in this paper; the critical supporting pressures of the collapse failure mechanism in different strata (sand and silt) were calculated. Through comparative analysis, the theoretical values were very close to the numerical values. This shows that the face failure mechanism of DOT shield tunnel is reasonable, and it can be applied to the sand and silt strata

A Black Raspberry-Rich Diet Protects From Dextran Sulfate Sodium-Induced Intestinal Inflammation and Host Metabolic Perturbation in Association With Increased Aryl Hydrocarbon Receptor Ligands in the Gut Microbiota of Mice

Dietary modulation of the gut microbiota recently received considerable attention, and ligand activation of aryl hydrocarbon receptor (AHR) plays a pivotal role in intestinal immunity. Importantly, black raspberry (BRB, Rubus occidentalis) is associated with a variety of beneficial health effects. We aim to investigate effects of a BRB-rich diet on dextran sulfate sodium (DSS)-induced intestinal inflammation and to determine whether its consequent anti-inflammatory effects are relevant to modulation of the gut microbiota, especially its production of AHR ligands. A mouse model of DSS-induced intestinal inflammation was used in the present study. C57BL/6J mice were fed either AIN-76A or BRB diet. Composition and functions of the gut microbiota were assessed by 16S rRNA sequencing and comparative metagenome analysis. Metabolic profiles of host and the gut microbiome were assessed by serum and fecal metabolomic profiling and identification. BRB diet was found to ameliorate DSS-induced intestinal inflammation and host metabolic perturbation. BRB diet also protected from DSS-induced perturbation in diversity and composition in the gut microbiota. BRB diet promoted AHR ligand production by the gut microbiota, as revealed by increased levels of fecal AHR activity in addition to increased levels of two known AHR ligands, hemin and biliverdin. Accordingly, enrichment of bacterial genes and pathways responsible for production of hemin and biliverdin were found, specific gut bacteria that are highly correlated with abundances of hemin and biliverdin were also identified. BRB dietary intervention ameliorated intestinal inflammation in mice in association with promotion of AHR ligand production by the gut microbiota