Search

High-fat exposure leads to impaired intestinal barrier function by disrupting the function of intestinal stem cells (ISCs); however, the exact mechanism of this phenomenon is still not known. We hypothesize that high concentrations of deoxycholic acid (DCA) in response to a high-fat diet (HFD) affect aryl hydrocarbon receptor (AHR) signalling in ISCs and the intestinal barrier. For this purpose, C57BL/6J mice feeding on a low-fat diet (LFD), an HFD, an HFD with the bile acid binder cholestyramine, and a LFD with the DCA were studied. We found that high-fat feeding induced an increase in faecal DCA concentrations. An HFD or DCA diet disrupted the differentiation function of ISCs by downregulating AHR signalling, which resulted in decreased goblet cells (GCs) and MUC2, and these changes were reversed by cholestyramine. In vitro experiments showed that DCA downregulated the differentiation function of ISCs, which was reversed by the AHR agonist 6-formylindolo [3,2-b]carbazole (FICZ). Mechanistically, DCA caused a reduction in indoleamine 2,3-dioxygenase 1 (IDO1) in Paneth cells, resulting in paracrine deficiency of the AHR ligand kynurenine in crypts. We demonstrated for the first time that DCA disrupts intestinal mucosal barrier function by interfering with AHR signalling in ISCs. Supplementation with AHR ligands may be a new therapeutic target for HFD-related impaired intestinal barrier function. [ABSTRACT FROM AUTHOR]

The thermo-physiological human simulator has been used in many regions for estimating thermal behavior of the locals. The applicability of the human simulator to populations from different regions is, however, questioned due to its lack of consideration for the ethnic diversities in thermoregulation. This study checked the potential of improving the applicability of the Newton human simulator, one of the most popular simulators, by correcting its local set point skin temperatures according to the target population (Chinese as an example). First, new set point skin temperatures were obtained by conducting tests with 101 Chinese under a thermal neutral condition. Then, simulator tests using the original and new set point skin temperatures were conducted separately for evaluating thermal responses of the Chinese under non-neutral conditions. The evaluated skin and core temperatures by the simulators were compared with those measured from the real human tests. It demonstrated that the evaluated skin temperatures are positively related with the set point skin temperatures of the simulator. Adjusting set point skin temperatures according to the Chinese improved the prediction performance of the local skin temperatures, with the root-mean-square-deviation being reduced for over 50% of the body segments. The proposed idea of correcting local set point skin temperatures would contribute to evaluating the thermal interaction between human body and its surroundings with a higher accuracy. [ABSTRACT FROM AUTHOR]

Using reclaimed asphalt pavement (RAP) has become an appealing development for economic and environmental benefits. One of the key issues when incorporating RAP materials is to ensure the performance of recycled binder blends. Despite extensive researches dealing with physical and chemical aspects, concerns about recycled materials combinations remain. This paper focuses on the kinetics of aging, cracking and healing process for blended binders with a novel hypothesis of mass-composite activation energies. Firstly, four blends were prepared with different ratios of virgin bitumen and laboratory-produced RAP binders. Then, Fourier-transform infrared spectroscopy was utilized to track the carbonyl formation in all samples initially and with aging, and aging activation energy (E acr) was computed in terms of Arrhenius equation. Thirdly, strain-controlled oscillatory measurements were conducted; moreover, representative energy change rates of dissipated pseudo strain energy and recoverable strain energy were obtained to determine the activation energy for cracking (E ac) and healing (E aH), respectively. Finally, hypotheses of mass-composite activation energies were validated with the test results. It shows that E acr of recycled binder blends are smaller than that of RAP binders, indicating a lower kinetic barrier to oxidation reaction for blended bituminous system. With the increase of RAP binder content, the blends exhibit a decrease in E ac and an increase in E aH , which reveals the adverse effect introduced by oxidation in cracking resistance and healing capability. Excitingly, the measured activation energies of recycled binder blends are consistent with the calculated mass-composite activation energies, which will hopefully provide support for performance estimation. [Display omitted] • Kinetics of aging, cracking and healing are studied on blended bituminous system. • Mass-composite rule of activation energy is established for recycled binder blends. • The proposed mass-composite activation energies are validated. [ABSTRACT FROM AUTHOR]

• A 'skin-electrically heated fabric-environment' heat transfer model was established. • Temperature and inner layer's thermal resistance affect T sk a more than other factors. • A prediction model for resultant skin temperature was developed. • The optimization design balances human thermal comfort and energy saving. A 3D heat transfer model was developed to optimize the design of electric heating garments (EHGs) towards human thermal comfort and energy efficiency. The model deals with the thermal interaction between human skin, a three-layer electrical heating fabric system, and cold environments, allowing analysis of the heating process and resultant skin temperature. Three heat transfer mechanisms, namely conduction, convection and radiation, were considered. The real-time and final skin temperatures from simulation and measurement exhibited a difference below 4%, demonstrating the efficiency of the model. A steady-state parametric study was conducted using the validated numerical model. Five parameters, such as heating temperature, thermal resistance of the inner and outer fabrics, wind speed, and environmental air temperature, were involved. The results indicate that the heating temperature and thermal resistance of the inner fabric have a more noticeable effect on the temperature of the skin surface below the heated area compared to the other three factors. Apart from the heating temperature, the other four factors have a greater impact on the skin temperature of non-heated regions than that of the heated region. Multiple linear regression analysis was performed to establish a relationship between skin temperature and the five factors. Based on this analysis, a prediction model for skin temperature was developed and subsequently used to determine relevant parameters for EHGs. A method for optimizing the design of electrically heated clothing is proposed, which can achieve the dual goals of human thermal comfort and energy efficiency. [ABSTRACT FROM AUTHOR]

White matter hyperintensities (WMH) are widely observed in older adults and are closely associated with cognitive impairment. However, the underlying neuroimaging mechanisms of WMH-related cognitive dysfunction remain unknown. This study recruited 61 WMH individuals with mild cognitive impairment (WMH-MCI, n = 61), 48 WMH individuals with normal cognition (WMH-NC, n = 48) and 57 healthy control (HC, n = 57) in the final analyses. We constructed morphological networks by applying the Kullback-Leibler divergence to estimate interregional similarity in the distributions of regional gray matter volume. Based on morphological networks, graph theory was applied to explore topological properties, and their relationship to WMH-related cognitive impairment was assessed. There were no differences in small-worldness, global efficiency and local efficiency. The nodal local efficiency, degree centrality and betweenness centrality were altered mainly in the limbic network (LN) and default mode network (DMN). The rich-club analysis revealed that WMH-MCI subjects showed lower average strength of the feeder and local connections than HC (feeder connections: P = 0.034; local connections: P = 0.042). Altered morphological connectivity mediated the relationship between WMH and cognition, including language (total indirect effect: −0.010; 95 % CI: −0.024, −0.002) and executive (total indirect effect: −0.010; 95 % CI: −0.028, −0.002) function. The altered topological organization of morphological networks was mainly located in the DMN and LN and was associated with WMH-related cognitive impairment. The rich-club connection was relatively preserved, while the feeder and local connections declined. The results suggest that single-subject morphological networks may capture neurological dysfunction due to WMH and could be applied to the early imaging diagnostic protocol for WMH-related cognitive impairment. • The altered topological organization of morphological networks was mainly located in the DMN and LN. • The altered morphological connectivity mediated WMH-related cognitive impairment. • The rich-club connection was relatively preserved to delay cognitive decline. [ABSTRACT FROM AUTHOR]

• Heat transfer from dressed human body was simulated using a validated CFD method. • Heat transfer distributes unevenly over human body covered with homogeneous air layer. • Considering only average value of the air gap thickness underestimates heat transfer. • Environmental air enters air layer through clothes openings and promote heat transfer. • Air speed decreases the threshold of air gap thickness for the onset of convection. With a great advantage of presenting physical phenomenon in a three-dimensional vision, the technology of computational fluid dynamics was utilized in the current study for simulating and revealing heat transfer in the air gap/layer between human body and clothing. Five clothing configurations including one with realistic heterogeneous air layer and four simplified ones with homogeneous air layers with air gap thickness (AGT) varying between 4 and 16.34 mm were built. All clothing configurations were simulated under environmental air speeds of 0.2–2.5 m/s. It was found the thermal plume, airflow through clothing openings and pathway at armhole have resulted in an uneven distribution of heat transfer underneath clothing, even for clothing with homogeneous air layers. Simply averaging AGT blurs the heterogeneity of heat transfer over the whole body. The threshold of AGT for arising free convection in the air gap is within 12–16.34 mm at the air speed of 0.2 m/s and 8–12 mm at 2.5 m/s, indicating a substantial influence of environmental airflow on thermal flow in the air gap. Besides, increase of air speed would enhance local heat exchange by entering the air gap through clothing openings, except at the arms, where the heat flux fluctuates due to the direction of airflow in sleeves changing from upwards to downwards. Results of the current study have offered a comprehensive insight into the heat transfer in the air gap and can contribute to improving the accuracy of analytical human – clothing – environment models in clothing thermal engineering. [ABSTRACT FROM AUTHOR]

l Incorporating origami into the armor design, breaking the traditional armor design concept. l Arc-armor can better protect the structures with curved surfaces. l Introducing origami can induce a stable and regular failure mode of the arc-scale. l The origami-based arc-scales have greatly improved the protection performance of the armor. l The second-level structure can further reduce the peak load of the scales under high-velocities for about 19.7%. Natural dermal armor has superior protective performance and flexibility for effectively protecting flexible objects. Limited by the complex microstructure of natural scales, the scales of common bionic armors are mostly solid flat scales, which will have a certain impact on the quality and protective performance of the armor, and they are not suitable for protecting flexible objects with a curved surface out of consideration for conformality and performance. Based on the Miura pattern with single-degree-of-freedom, this paper designs an arc-scale that can be conformal to the curved surface, and proposes an arc-armor inspired by fish scales. The experiments and numerical simulations have proved that the introduction of the origami structure design can induce a stable failure mode of the arc-scale. The origami-based arc-armor has the advantages of low peak load, long effective stroke, and small fluctuation, which greatly improves the protection performance of the armor. And based on the failure mode of the arc-scale, the second-level structure is proposed to further optimize the energy absorption characteristics of the arc-scale, which contributes to reducing the peak load of the scales under medium- and high-velocity impacts. Under high-velocity impact, the denser the distribution of cells inside the scales, the higher the energy absorption efficiency of the arc-scales, which provides certain guidance for the design and application of the arc-armor. We have obtained an arc-armor with excellent energy absorption characteristics that can be reverse-designed according to the target shape. And such structures can find a wide range application in the protection of flexible electronics, human bodies, and other flexible objects that require light weight and flexibility. [Display omitted] [ABSTRACT FROM AUTHOR]

Triggering receptor expressed on myeloid cells 2 (TREM2) is an important member of the immunoglobulin family of inflammatory stimulating receptors and is involved in a number of pathophysiological processes. The present study aimed to investigate the role of TREM2 in neurotoxicity induced by high cholesterol levels in SH-SY5Y cells and explore the potential mechanism. SH-SY5Y cells were routinely cultured and stimulated with a range of cholesterol concentrations. Cell viability was assessed using an MTT assay, morphological changes were observed, and the cell cycle distribution was measured using flow cytometry. Lipid deposition was measured by Oil red O staining, and the mRNA and protein expression levels of SRBEP-1 and SRBEP-2 were detected by quantitative PCR and western blotting, respectively. Moreover, the protein expression levels of BDNF, Copine-6, TREM1, TREM2, and key molecules of the Wnt signaling pathways were detected by western blotting. Finally, TREM2 was overexpressed to investigate its potential role in high cholesterol-induced neurotoxicity. The results showed that cell viability was significantly decreased in SH-SY5Y cells stimulated with cholesterol (0.1~100 µM) in a dose- and time-dependent manner. Stimulation with 100 µM cholesterol for 24 h resulted in morphological injuries, increased the proportion of SH-SY5Y cells at G0/G1, the degree of lipid accumulation, and the protein expression levels of sterol regulatory element binding protein (SREBP)1 and SREBP2, markedly decreased the protein expression levels of BDNF, Copine-6, and TREM2, and the p-β-catenin/β-catenin ratio, and increased the expression levels of nesfatin-1, TREM1 and the p-GSK3β/GSK3β ratio. Furthermore, the imbalanced expression of BDNF, Copine-6, nesfatin-1, and p-GSK3β induced by high cholesterol levels was reversed after overexpression of TREM2. These results suggest that a high concentration of cholesterol could induce cell injury and lipid deposition in SH-SY5Y cells and that the underlying mechanism may be associated with imbalanced TREM2 expression. [ABSTRACT FROM AUTHOR]