Recent studies have found gut microbiota to be closely associated with onset and perpetuation of UC. Currently, studies about gut microbiota have mainly covered samples collected from the intestinal ...lumen. However, the luminal flora is only part of the gut microbiota. Studies of the changes in mucosal flora under pathological conditions have been lacking. In this study, we investigated the correlation between the onset of UC and flora changes in different intestinal layers.
The dextran sulfate sodium(DSS)-induced UC model was established by exposing mice to cycles of DSS. The luminal contents, an inner mucus layer, and outer mucus layer were harvested under sterile conditions. The samples were then analyzed using high-throughput sequencing of 16S rRNA V3 + V4 amplicons. The colonic microbiota composition and diversity were analyzed and compared using MetaStat, LefSe, multivariate analysis of variance, and spatial statistics.
The DSS-induced UC mouse model was successfully established. The diversity of the microbiota from luminal content, the outer mucus layer, and inner mucus layer were significantly different in both control and UC model groups. The statistically different OTUs belonged to Lachnospiraceae and Ruminococcaceae families within the order Clostridiales were mainly localized to the outer mucus layer.
The alterations in flora composition and diversity mainly occurred in the colonic outer mucus layer. The change of flora in the colonic mucus layers is of great significance in the understanding of common features of gut flora in IBD and the understanding of the relationship between gut flora and disease progression.
The highly contagious and fast-spreading omicron variant of SARS-CoV-2 infects the respiratory tracts efficiently. The receptor-binding domain (RBD) of the omicron spike protein recognizes human ...angiotensin-converting enzyme 2 (ACE2) as its receptor and plays a critical role in the tissue tropism of SARS-CoV-2. Here, we showed that the omicron RBD (strain BA.1) binds to ACE2 more strongly than does the prototypic RBD from the original Wuhan strain. We also measured how individual omicron mutations affect ACE2 binding. We further determined the crystal structure of the omicron RBD (engineered to facilitate crystallization) complexed with ACE2 at 2.6 Å. The structure shows that omicron mutations caused significant structural rearrangements of two mutational hot spots at the RBD/ACE2 interface, elucidating how each omicron mutation affects ACE2 binding. The enhanced ACE2 binding by the omicron RBD may facilitate the omicron variant's infection of the respiratory tracts where ACE2 expression level is low. Our study provides insights into the receptor recognition and tissue tropism of the omicron variant.
Despite the scarcity of the SARS-CoV-2 receptor-human angiotensin-converting enzyme 2 (ACE2)-in the respiratory tract, the omicron variant efficiently infects the respiratory tract, causing rapid and widespread infections of COVID-19. The omicron variant contains extensive mutations in the receptor-binding domain (RBD) of its spike protein that recognizes human ACE2. Here, using a combination of biochemical and X-ray crystallographic approaches, we showed that the omicron RBD binds to ACE2 with enhanced affinity and also elucidated the role of each of the omicron mutations in ACE2 binding. The enhanced ACE2 binding by the omicron RBD may contribute to the omicron variant's new viral tropism in the respiratory tract despite the low level of ACE2 expression in the tissue. These findings help us to understand tissue tropism of the omicron variant and shed light on the molecular evolution of SARS-CoV-2.
Due to the harsh operating environment and ultralong operating hours of wireless sensor networks (WSNs), node failures are inevitable. Ensuring the reliability of the data collected by the WSN ...necessitates the utmost importance of diagnosing faults in nodes within the WSN. Typically, the initial step in the fault diagnosis of WSN nodes involves extracting numerical features from neighboring nodes. A solitary data feature is often assigned a high weight, resulting in the failure to effectively distinguish between all types of faults. Therefore, this study introduces an enhanced variant of the traditional belief rule base (BRB), called the belief rule base with adaptive attribute weights (BRB-AAW). First, the data features are extracted as input attributes for the model. Second, a fault diagnosis model for WSN nodes, incorporating BRB-AAW, is established by integrating parameters initialized by expert knowledge with the extracted data features. Third, to optimize the model's initial parameters, the projection covariance matrix adaptive evolution strategy (P-CMA-ES) algorithm is employed. Finally, a comprehensive case study is designed to verify the accuracy and effectiveness of the proposed method. The results of the case study indicate that compared with the traditional BRB method, the accuracy of the proposed model in WSN node fault diagnosis is significantly improved.
Sordariomycetes
is one of the largest classes of
Ascomycota
and is characterised by perithecial ascomata and inoperculate unitunicate asci. The class includes many important plant pathogens, as well ...as endophytes, saprobes, epiphytes, and fungicolous, lichenized or lichenicolous taxa. The class includes freshwater, marine and terrestrial taxa and has a worldwide distribution. This paper provides an updated outline of the
Sordariomycetes
and a backbone tree incorporating asexual and sexual genera in the class. Based on phylogeny and morphology we introduced three subclasses;
Diaporthomycetidae, Lulworthiomycetidae
and
Meliolomycetidae
and five orders;
Amplistromatales
,
Annulatascales
,
Falcocladiales
,
Jobellisiales
and
Togniniales
. The outline is based on literature to the end of 2014 and the backbone tree published in this paper. Notes for 397 taxa with information, such as new family and genera novelties, novel molecular data published since the Outline of Ascomycota 2009, and new links between sexual and asexual genera and thus synonymies, are provided. The Sordariomycetes now comprises six subclasses, 28 orders, 90 families and 1344 genera. In addition a list of 829 genera with uncertain placement in
Sordariomycetes
is also provided.
Abstract
Flexible reinforcements are a promising option in slope engineering owing to their mechanical strength and ecological restoration. An in-depth understanding of the mechanical behavior of a ...slope reinforced by an anchored geomat system is required to analyze the slope stability and to optimize engineering design. In this study, physical modeling experiments are conducted to investigate the global performance and ultimate capacity of the reinforced slope under different loading levels. A stability model of the reinforced slope and the corresponding computing method are proposed based on a limit equilibrium framework in integral form. Subsequently, the contribution of a flexible protection system and its components to safety factors are quantified against loading tests. The results show that lateral deformation is concentrated in the middle of the reinforced slope, from which the potential failure surface can be derived. The stability enhancement of the reinforced slope is primarily attributed to the anchor bolts, and an increase in cohesion and internal friction angle increases the safety factor more significantly under low-level overloads. This study provides a benchmark for slopes reinforced by an anchored geomat system, which is promising for application in slope engineering.
The micromechanical strain cycle fatigue-life is systematically investigated by the micro-level numerical simulation, compared with symmetrical strain cycle experiments of copper, focusing on the ...characteristics of polycrystalline aggregation and the mechanism of microscale plastic deformation. A methodology to predict the low-cycle fatigue life by micro-level simulation along with statistical analysis is proposed through the following steps: (1) A crystal plasticity model is developed based on the nonlinear kinematic hardening mechanism of crystal slipping system. This model is applied to the calculations of crystal grain interior stresses and plastic strains. (2) A statistical representative volume element (SRVE) is constructed for a pure copper as a material model which features a polycrystalline Voronoi aggregation consisting of a number of crystal grains. This SRVE can be used for statistical analysis of the material inhomogeneous stresses and strains during cycle loading. (3) The simulations are performed to model the experimental cycle evolution of strain fatigue by using the SRVE under the symmetrical tensile–compressive loading. (4) Statistical and micromechanical analyses are carried out for the inhomogeneous interior stresses and strains of the SRVE of the polycrystalline copper in the low cycle regime. The resulting analysis can render the microscale interpretation and numerical simulation for the low-cycle fatigue evolution accordingly.
Objectives
Transient elastography (TE), as a non‐invasive method, has been studied for evaluation of portal hypertension in patients with chronic liver diseases (CLD) with variable results. We ...studied the performance of TE for detection of significant portal hypertension, oesophageal varices and large oesophageal varices using meta‐analysis.
Methods
PubMed, the Cochrane Library, EMBASE and ISI web of Knowledge were searched. The studies published in English relating to the diagnostic value of TE for significant portal hypertension, oesophageal varices and large oesophageal varices in patients with CLD were collected.
Results
A total of 18 studies, which included 3644 patients were analysed. Summary sensitivity and specificity were 0.90 (95% confidence interval (CI), 0.81–0.95) and 0.79 (95% CI, 0.58–0.91) for significant portal hypertension, and 0.87 (95% CI, 0.80–0.92) and 0.53 (95% CI, 0.36–0.69) for oesophageal varices and 0.86 (95% CI, 0.71–0.94) and 0.59 (95% CI, 0.45–0.72) for large oesophageal varices respectively. The HSROCs were 0.93 for significant portal hypertension, 0.84 for oesophageal varices and 0.78 for large oesophageal varices respectively. TE was very informative with 81% probability of correctly detection significant portal hypertension following a ‘positive’ measurement (over the threshold value) and lowering the probability of disease to as low as 11% when ‘negative’ measurement (below the threshold value) when pre‐test probability was 50% whereas, for oesophageal varices or large oesophageal varices, the probability of a correct diagnosis following a ‘positive’ measurement did not exceeded 70%.
Conclusions
TE could be used as a good screening tool for significant portal hypertension, but only moderate diagnostic utility for the prediction of oesophageal varices or large oesophageal varices.
In this paper a one-dimensional numerical study on the nonlinear behaviour of an electrically charged jet of Oldroyd-B viscoelastic, Taylor–Melcher leaky dielectric liquid is carried out. The effect ...of surface charge level, axial wavenumber and finite conductivity on the nonlinear evolution of the jet is investigated. Different structures including beads-on-a-string with/without satellite droplets, quasi-spikes and spikes are detected, and their domains in the plane of the non-dimensional axial wavenumber and the electrical Bond number are illustrated. The underlying mechanisms in the formation of the structures are examined. It is found that tangential electrostatic force plays a key role in the formation of a quasi-spike structure. Decreasing liquid conductivity may lead to a decrease in the size of satellite droplets or even the complete removal of them from a beads-on-a-string structure, induce the transition from a beads-on-a-string to a quasi-spike structure or postpone the appearance of a spike. On the other hand, finite conductivity has little influence on filament thinning in a beads-on-a-string structure, owing to the fact that the electrostatic forces are of secondary importance compared with the capillary force. The difference between the finite conductivity, large conductivity and other cases is elucidated. An experiment is carried out to observe spike structures.
We present a new hybridizable discontinuous Galerkin (HDG) method for the convection diffusion problem on general polyhedral meshes. This new HDG method is a generalization of HDG methods for linear ...elasticity introduced in Qiu and Shi (
2013
) to problems with convection term. For arbitrary polyhedral elements, we use polynomials of degree
k
+
1
and
k
≥
0
to approximate the scalar variable and its gradient, respectively. In contrast, we only use polynomials of degree
k
to approximate the numerical trace of the scalar variable on the faces which allows for a very efficient implementation of the method, since the numerical trace of the scalar variable is the only globally coupled unknown. The global
L
2
-norm of the error of the scalar variable converges with the order of
k
+
2
while that of its gradient converges with order
k
+
1
. From the point of view of degrees of freedom of the globally coupled unknown: numerical trace, this method achieves superconvergence for the scalar variable without postprocessing. A key inequality relevant to the discrete Poincaré inequality is a novel theoretical contribution. This inequality is useful to deal with convection term in this paper and is essential to error analysis of HDG methods for the Navier–Stokes equations and other nonlinear problems.
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