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The present study was carried out to evaluate the effect of dietary supplementation of Scutellaria baicalensis extracts (SBE) on intestinal health in terms of morphology, barrier integrity and immune responses in weaned piglets challenged with Escherichia coli K88. A total of seventy-two weaned piglets were assigned into two groups to receive a basal diet without including antibiotic additives or the basal diet supplemented 1000 mg SBE/kg diet for 14 d. On day 15, twelve healthy piglets from each group were selected to expose to oral administration of either 10 ml 1 × 109 colony-forming units of E. coli K88 or the vehicle control. After 48 h of E.coli K88 challenge, blood was sampled, and then all piglets were killed humanely for harvesting jejunal and ileal samples. Dietary supplementation of SBE significantly decreased diarrhoea frequency and improved feed conversion ratio (P < 0·05). SBE supplementation to E.coli K88-challenged piglets improved villous height and villous height/crypt depth (P < 0·05), recovered the protein expression of occludin and zonula occludens-2 in both the jejunum and ileum (P < 0·05), and mitigated the increases in plasma IL-1β, TNF-α, IL-6, IgA and IgG (P < 0·05). Meanwhile, dietary SBE effectively inhibited the stimulation of NF-κB, P38 and TNF-α as well as IL-1β in the small intestine of piglets challenged by E. coli K88 and prevented the activation of NF-κB/P38 signalling pathways (P < 0·05). Collectively, SBE supplementation can potently attenuate diarrhoea in weaning piglets and decrease inflammatory cytokine expressions through inhibiting the NF-κB and P38 signalling pathways.
Concerns over food safety in China not only direct public attention to negative
incidents, but also trigger the government's scrutiny of implicated
firms, particularly MNCs. The question of how to repair legitimacy after media
coverage of negative incidents has become a critical issue for MNCs. Although
the factors for MNCs’ public crises have been identified, how local
contexts and mechanisms shape repair approaches remain unclear. To address this
research gap, we conducted a study of Walmart China's approaches
associated with two negative incidents across two regions. We found that the
negative incidents can be framed differently depending on the local
environment's unfavorability for MNCs. Specifically, the negative
framing gave rise to varying degrees of legitimacy loss and offered different
leeway for MNCs to repair their legitimacy. We also identified the varied
outcomes of different repair approaches. By revealing the linkages among local
context, framing, legitimacy repair, and its outcomes, our study contributes to
research on MNCs’ legitimacy management under institutional
complexity and underscores the China context for legitimacy maintenance. We also
offer insights that advance the institutional approach to legitimacy repair in
this context. Last, we reflect on the techniques for conducting qualitative
research in China.
Small luminescent Y2O3:Eu3+ particles were prepared by a hydrothermal method first, and then, Y2O3:Eu3+/C3N4 nanocomposites were further prepared by a chemisorption method. The luminescent Y2O3:Eu3+/C3N4 nanocomposites are not only a promising down-conversion luminescent material, but also it could be used to improve the efficiencies of dye-sensitized solar cells (DSSCs). Especially, the morphology of Y2O3:Eu3+ has great influence on the performance of DSSCs. Compared with Y2O3:Eu3+ nanorods, the introduction of small Y2O3:Eu3+ particles into the cells is conducive to the improvement of cell efficiency. The efficiencies of TiO2-Y2O3:Eu3+–C3N4 composite cells were not only higher than those of pure TiO2 cells but also higher than those of TiO2-Y2O3:Eu3+ or TiO2-C3N4 composite cells, resulting in the enhancement of the average efficiency of the TiO2-Y2O3:Eu3+–C3N4 composite cell from 7.16% to 8.14%, with 14% improvement over the pure TiO2 cell. The enhancement of the efficiency can be attributed to the synergetic effect of small Y2O3:Eu3+ particles and C3N4.
We hypothesize that the tumor necrosis factor-α (TNF-α) may play a role in disturbing the effect of selective serotonin reuptake inhibitor (SSRI) on the striatal connectivity in patients with major depressive disorder (MDD).
We performed a longitudinal observation by combining resting-state functional magnetic resonance imaging (rs-fMRI) and biochemical analyses to identify the abnormal striatal connectivity in MDD patients, and to evaluate the effect of TNF-α level on these abnormal connectivities during SSRI treatment. Eighty-five rs-fMRI scans were collected from 25 MDD patients and 35 healthy controls, and the scans were repeated for all the patients before and after a 6-week SSRI treatment. Whole-brain voxel-wise functional connectivity (FC) was calculated by correlating the rs-fMRI time courses between each voxel and the striatal seeds (i.e. spherical regions placed at the striatums). The level of TNF-α in serum was evaluated by Milliplex assay. Factorial analysis was performed to assess the interaction effects of ‘TNF-α × treatment’ in the regions with between-group FC difference.
Compared with controls, MDD patients showed significantly higher striatal FC in the medial prefrontal cortex (MPFC) and bilateral middle/superior temporal cortices before SSRI treatment (p < 0.001, uncorrected). Moreover, a significant interaction effect of ‘TNF-α × treatment’ was found in MPFC-striatum FC in MDD patients (p = 0.002), and the significance remained after adjusted for age, gender, head motion, and episode of disease.
These findings provide evidence that treatment-related brain connectivity change is dependent on the TNF-α level in MDD patients, and the MPFC-striatum connectivities possibly serve as an important target in the brain.
The overuse of antibiotics and the rapid emergence of antibiotic resistance prompted the launch of an antimicrobial stewardship programme in 2011. This study aimed to investigate the trends and correlations between antibiotic consumption and resistance of Staphylococcus aureus in a tertiary hospital of northwest China from 2010 to 2016. Trends were analysed by linear regression, and correlations were assessed by an autoregressive integrated moving average model. The total consumption of antibiotics halved during the 7-year study period, while the rates of resistance of S. aureus decreased significantly or remained stable; methicillin-resistant S. aureus (MRSA) declined markedly, from 73.3% at the beginning of the study to 41.4% by the end. This latter decrease was significantly correlated with the consumption of several classes of antibiotics. In conclusion, reduction in antibiotic use impacted significantly on resistance rates and contributed to a decline in MRSA prevalence.
Electroconvulsive therapy (ECT), an effective antidepressive treatment, is frequently accompanied by cognitive impairment (predominantly memory), usually transient and self-limited. The hippocampus is a key region involved in memory and emotion processing, and in particular, the anterior-posterior hippocampal subregions has been shown to be associated with emotion and memory. However, less is known about the relationship between hippocampal-subregion alterations following ECT and antidepressant effects or cognitive impairments.
Resting-state functional connectivity (RSFC) based on the seeds of hippocampal subregions were investigated in 45 pre- and post-ECT depressed patients. Structural connectivity between hippocampal subregions and corresponding functionally abnormal regions was also conducted using probabilistic tractography. Antidepressant effects and cognitive impairments were measured by the Hamilton Depressive Rating Scale (HDRS) and the Category Verbal Fluency Test (CVFT), respectively. Their relationships with hippocampal-subregions alterations were examined.
After ECT, patients showed increased RSFC in the hippocampal emotional subregion (HIPe) with the left middle occipital gyrus (LMOG) and right medial temporal gyrus (RMTG). Decreased HDRS was associated with increased HIPe-RMTG RSFC (r = −0.316, p = 0.035) significantly and increased HIPe-LMOG RSFC at trend level (r = −0.283, p = 0.060). In contrast, the hippocampal cognitive subregion showed decreased RSFC with the bilateral angular gyrus, and was correlated with decreased CVFT (r = 0.418, p = 0.015 for left; r = 0.356, p = 0.042 for right). No significant changes were found in structural connectivity.
The hippocampal-subregions functional alterations may be specially associated with the antidepressant and cognitive effects of ECT.
Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy cosmic rays. Until now, understanding these micro-processes is still a challenge despite rich astrophysical observation data have been obtained. Laboratory astrophysics, a new route to study the astrophysics, allows us to investigate them at similar extreme physical conditions in laboratory. Here we will review the recent progress of the collisionless shock experiments performed at SG-II laser facility in China. The evolution of the electrostatic shocks and Weibel-type/filamentation instabilities are observed. Inspired by the configurations of the counter-streaming plasma flows, we also carry out a novel plasma collider to generate energetic neutrons relevant to the astrophysical nuclear reactions.
High-precision underwater positioning must eliminate the influence of refraction artefacts. Since a Time Of Arrival - Global Navigation Satellite System Intelligent Buoys (TOA-GIB) system does not measure incident beam angles, common refraction correction methods cannot be directly used for refraction artefacts. An Equivalent Sound Speed (ESS) iteration method is proposed and is based on the transformation relations between depth, the ESS gradient and the incident beam angle. On this basis, a TOA/AOA-GIB system without a real-time Sound Speed Profile (SSP) is proposed to estimate the target position and the ESS gradient as unknown parameters. The results from a simulation experiment show that the positioning accuracy of a TOA/AOA-GIB system is better than 0·07% of water depth when the accuracy of the incident beam angle is 0·1°.
Increasing ship traffic and human activity in the Arctic has led to a growing demand for accurate Arctic weather forecast. High-quality forecasts obtained by models are dependent on accurate initial states achieved by assimilation of observations. In this study, a multi-variate nudging (MVN) method for assimilation of sea-ice variables is introduced. The MVN assimilation method includes procedures for multivariate update of sea-ice volume and concentration, and for extrapolation of observational information spatially. The MVN assimilation scheme is compared with the Ensemble Kalman Filter (EnKF) using the Los Alamos Sea Ice Model. Two multi-variate experiments are conducted: in the first experiment, sea-ice thickness from the European Space Agency's Soil Moisture and Ocean Salinity mission is assimilated, and in the second experiment, sea-ice concentration from the ocean and Sea Ice Satellite Application Facility is assimilated. The multivariate effects are cross-validated by comparing the model with non-assimilated observations. It is found that the simple and computationally cheap MVN method shows comparable skills to the more complicated and expensive EnKF method for multivariate update. In addition, we show that when few observations are available, the MVN method is a significant model improvement compared to the version based on one-dimensional sea-ice concentration assimilation.
The pricing model for American lookback options can be characterised as a two-dimensional free boundary problem. The main challenge in this problem is the free boundary, which is also the main concern for financial investors. We use a standard technique to reduce the pricing model to a one-dimensional linear complementarity problem on a bounded domain and obtain a corresponding variational inequality. The inequality is discretised by finite differences and finite elements in the temporal and spatial directions, respectively. By enforcing inequality constraints related to the options using Lagrange multipliers, the discretised variational inequality is reformulated as a set of semi-smooth equations, which are solved by a primal-dual active set method. One of the major advantages of our algorithm is that we can obtain the option values and the free boundary simultaneously, and numerical simulations show that our approach is as efficient as some other methods.
Unlike industrial-grade Inertial Navigation Sensors (INSs) that can provide credible tracking performance, more affordable consumer-grade low-cost INSs produce drifts in heading angles and positions that result in a poor tracking accuracy. Researchers have proposed drift correction methods that attempt to attenuate the drifts when walking straight along the dominant directions is detected. While determining the type of a pedestrian's walk is essential before the heading corrections are made, the current detection techniques heavily rely on thresholding. This paper proposes a novel threshold-less method to detect turns in walking by using pelvic rotation and correct the heading angle based on consumer-grade INSs. The experiments indicate the proposed turn detector and heading correction methods produce very good results which can be applied for future pedestrian tracking, activity recognition or rehabilitation.
To prevent spinning of the upper non-rotated part of the electromechanical drill, an ‘anti-torque system’ has to be included in the downhole unit. At the same time, the anti-torque must allow the drill to move up and down the borehole during drilling and tripping operations. Usually the anti-torque system has a blade form of various designs that engages with the borehole wall and counteracts the torque from the stator of the driving motor. This paper presents a review of the different anti-torque systems and test results with selected designs (leaf spring, skate and U-shaped anti-torque systems). Experiments showed that the skate anti-torque system can provide the maximal holding torque between 67 and 267 Nm−1 depending on the skates’ outer diameter and ice temperature, while the leaf spring anti-torque system can provide only 2.5–40 N m−1 (in case of straight contact between the ice and the leaf springs). The total resistance force to axial movement of the skate anti-torque system lies in the range 209–454N if the system is vibrating. For the leaf spring anti-torque system, the total axial resistance force is far less (19–243 N).
The present study examines the characteristics of clay minerals in shale gas reservoirs and their influence on reservoir properties based on X-ray diffraction and scanning electron microscopy. These analyses were combined with optical microscopy observations and core and well-log data to investigate the genesis, distribution characteristics, main controlling factors and pore features of clay minerals of the Lower Silurian Longmaxi Formation in the East Sichuan area, China. The clay mineral assemblage consists of illite + mixed-layer illite-smectite (I-S) + chlorite. This assemblage includes three sources of clay minerals: detrital, authigenic and diagenetic minerals. The lower section of the Longmaxi Formation in the Jiaoshiba area has sealing ability which resulted in abnormal high pressures during hydrocarbon generation which inhibited illitization. Therefore, an anomalous transformation sequence is present in which the mixed-layer I-S content increases with depth. This anomalous transformation sequence can be used to infer the existence of abnormal high pressures. The detrital components of the formation also affect the clay-minerals content indirectly, especially the abundance of K-feldspar. The transformation of mixed-layer I-S to illite is limited due to the limited availability of K+, which determines the extent of transformation. Three types of pores were observed in the shale reservoir rocks of the Longmaxi Formation: interparticle (interP) pores, intraparticle (intraP) pores and organic-matter pores. The clay-mineral content controls the development of intraP pores, which are dominated by pores within clay particles. For a given clay mineral content, smectite and mixed-layer I-S were more conducive to the development of shale-gas reservoirs than other clay minerals.
Vision navigation using environmental features has been widely applied when satellite signals are not available. However, the matching performance of traditional environmental features such as keypoints degrades significantly in weakly textured areas, deteriorating navigation performance. Further, the user needs to evaluate and assure feature matching quality. In this paper, a new feature, named Line Segment Intersection Feature (LSIF), is proposed to solve the availability problem in weakly textured regions. Then a combined descriptor involving global structure and local gradient is designed for similarity comparison. To achieve reliable point-to-point matching, a coarse-to-fine matching algorithm is developed, which improves the performance of the point set matching algorithm. Finally, a framework of matching quality evaluation is proposed to assure matching performance. Through the comparison, it is demonstrated that the proposed new feature has superior overall performance especially on correctly matched numbers of keypoints and matching correctness. Also, using real image sets with weak texture, it is shown that the proposed LSIF can achieve improved navigation solutions with high continuity and accuracy.
The designs of inertial confinement fusion (ICF) targets, which field on ShenGuang III, are becoming more complex and more stringent in terms of assembly precision. A key specification of these targets is the spatial angle alignment accuracy. To meet these needs, we present a new spatial angle assembly method, using target part’s 3D model-based dual orthogonal camera vision, which is better suited for the flexible automation of target assembly processes. The two-hands structure micromanipulate system and dual orthogonal structure visual feedback system were investigated by considering the kinematics, spatial angle measuring, and motion control in an integrated way. In this paper, we discuss the measurement accuracy of spatial angle assembly method, which compared the real-time image acquisition with the redrawing 2D projection. The result shows that the assembly method proposed is very effective and meets the requirements of angle assembly accuracy, which is less than
. Also, this work is expected to contribute greatly to the advancement of other target microassembly equipments.
It is important to fabricate iron-based nitride/conductive material composite to obtain good catalytic performance. In this work, Fe2N nanoparticles with diameter of approximately 30 nm have been successfully dispersed on the surface of nitrogen-doped graphite oxide (NrGO) by a facile sol–gel method and further ammonia atmosphere treatment. XPS, XRD, Raman, and TEM proved that Fe2N nanoparticles are well monodispersed, and nitrogen atoms are doped in NrGO. The composite possessed two merits, that is, the more catalytic active site in Fe2N nanoparticles due to the well monodispersion, and fast electron transfer due to the nitrogen dope in rGO. With the proper ratio, the composite exhibited brilliant catalytic activity and durability in acidic media. It possesses overpotential of 94 mV to approach 10 mA/cm2, a small Tefel slope of 49 mV/dec, and maintains the good electrocatalytic activity for 10 h. Cyclic voltammetry and electrochemical impedance spectroscopy indicated that the electrocatalyst possessed high catalytic active area and fast electron transfer. Our work may provide a new avenue for the preparation of low-cost iron-based nitride/NrGO composite for highly efficient electrochemical hydrogen evolution.
We analyze in this paper the pressure splitting scheme of a partitioned semi-implicit coupling algorithm for fluid-structure interaction (FSI) simulation. The semi-implicit coupling algorithm is developed on the ground of the artificial compressibility characteristic-based split (AC-CBS) scheme that serves not only for the fluid subsystem but also for the global FSI system. As the dual-time stepping procedure recommended for quasi-incompressible flows is incorporated into the implicit coupling stage, the fluctuating pressure may be unusually susceptible to the AC coefficient. Moreover, it is not trivial to devise an optimal AC formulation for pressure estimation. Instead, we consider a stabilized second-order pressure splitting scheme in the AC-CBS-based partitioned semi-implicit coupling algorithm. Computer simulation of a benchmark FSI experiment demonstrates that good agreement is exposed between the available and present data.
Fetal growth discordance is a relatively common complication of monochorionic diamniotic (MCDA) twin pregnancies and is caused by a combination of maternal and placental factors. The aim of the study was to survey placental gene expression patterns and identify genes associated with growth discordance. Clinical samples comprised eight growth-discordant MCDA twin placentas (31+3–34+4 weeks gestational age) and six growth-concordant twin placentas (31+2–37 weeks gestational age). Gene expression libraries were constructed from placental biopsy samples and analyzed by RNA-sequencing. The distribution and relative abundance of mRNA transcripts expressed in the smaller and larger placentas from growth-discordant and concordant MCDA twins was remarkably similar. However, leptin (LEP) and age-related maculopathy susceptibility 2 (ARMS2) mRNA levels were exclusively up-regulated in all of the eight smaller growth-discordant twin placentas. Quantitative real-time PCR of independent biopsy samples confirmed the levels of differential mRNA expression for both genes. Immunohistochemical analysis of tissue sections from matching twin placentas showed increased leptin expression in 5–10% of blood vessel cells of the smaller placenta and marginally higher levels of ARMS2 expression in the microvillous membrane of the smaller placenta. Based on these findings, we speculate that up-regulation of leptin and ARMS2 forms part of an important survival mechanism to compensate for placental growth discordance. Since, leptin and ARMS2 are both expressed as soluble proteins, they may have clinical potential as measurable biomarkers for predicting the onset of growth discordance in MCDA twin pregnancies.
As the basic conditions for laser inertial confinement fusion (ICF) research, the targets are required to be well specified and elaborately fabricated. Because of the characteristics of the targets, the research and fabrication process is a systematically tough task, which needs fundamental and deep insights into film deposition, mechanical machining, precise measurement and assembly, etc. As a result, knowledge of material science, physics, mechanical as well as electronics is a necessity for target researchers. In this paper, we give introductions to the state of art on target fabrication for ICF research at Research Center of Laser Fusion (RCLF) in China.