Owing to their outstanding recentering capability, shape memory alloy (SMA) dampers are emerging as promising passive dampers for seismic applications. However, compared to typical seismic dampers, ...the inherent energy dissipation capability of SMAs is often deemed barely satisfactory. To enhance the damping capacity of SMA dampers, this study suggests combining SMA elements with steel dampers based on bending steel plates. In this new SMA-steel damper, the steel dampers are mainly responsible for absorbing seismic energy, whereas the SMA bars primarily play the role of recovering inelastic deformation. Experimental tests were conducted at room temperature to verify the cyclic behavior of the proposed damper. The hysteretic parameters, such as strength, stiffness, equivalent damping ratio, and residual deformation, are of particular interest and quantified as a function of the loading amplitude. According to test results, the new damper is confirmed to possess desirable recentering capability and high damping. To further understand the damper, numerical simulations were carried out in the finite element (FE) analysis software ABAQUS. The numerical results validated the experimental data. Based on the calibrated FE model, the thickness of the bending steel plate of the steel damper and the diameter of the SMA bars were varied in the parametric analysis to examine its effect on the recentering tendency and damping mechanism.
Understanding the dynamical processes that govern the performance of functional materials is essential for the design of next generation materials to tackle global energy and environmental ...challenges. Many of these processes involve the dynamics of individual atoms or small molecules in condensed phases, e.g. lithium ions in electrolytes, water molecules in membranes, molten atoms at interfaces, etc., which are difficult to understand due to the complexity of local environments. In this work, we develop graph dynamical networks, an unsupervised learning approach for understanding atomic scale dynamics in arbitrary phases and environments from molecular dynamics simulations. We show that important dynamical information, which would be difficult to obtain otherwise, can be learned for various multi-component amorphous material systems. With the large amounts of molecular dynamics data generated every day in nearly every aspect of materials design, this approach provides a broadly applicable, automated tool to understand atomic scale dynamics in material systems.
Risks of tumor recurrence after surgical resection have been known for decades, but the mechanisms underlying treatment failures remain poorly understood. Neutrophils, first-line responders after ...surgical stress, may play an important role in linking inflammation to cancer progression. In response to stress, neutrophils can expel their protein-studded chromatin to form local snares known as neutrophil extracellular traps (NET). In this study, we asked whether, as a result of its ability to ensnare moving cells, NET formation might promote metastasis after surgical stress. Consistent with this hypothesis, in a cohort of patients undergoing attempted curative liver resection for metastatic colorectal cancer, we observed that increased postoperative NET formation was associated with a >4-fold reduction in disease-free survival. In like manner, in a murine model of surgical stress employing liver ischemia-reperfusion, we observed an increase in NET formation that correlated with an accelerated development and progression of metastatic disease. These effects were abrogated by inhibiting NET formation in mice through either local treatment with DNAse or inhibition of the enzyme peptidylarginine deaminase, which is essential for NET formation. In growing metastatic tumors, we found that intratumoral hypoxia accentuated NET formation. Mechanistic investigations in vitro indicated that mouse neutrophil-derived NET triggered HMGB1 release and activated TLR9-dependent pathways in cancer cells to promote their adhesion, proliferation, migration, and invasion. Taken together, our findings implicate NET in the development of liver metastases after surgical stress, suggesting that their elimination may reduce risks of tumor relapse.
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•The composite probiotics increased SCFA-producing bacteria and decreased Escherichia coli.•The composite probiotics promoted GLP-1 secretion by upregulation of GPR43/41, GCG and ...PC1/3 activity.•The composite probiotics inhibited apoptosis via regulating PI3K/AKT signaling pathways.
Previous studies have found that probiotic fermented camel milk has anti-diabetic effect by inducing (glucagon-like peptide-1) GLP-1 secretion. Probiotics are valuable in prevention and treatment of diabetes. As a result, our team islolated 14 probiotics from fermented camel milk. These probiotics have beneficial characteristics, but the possible anti-diabetic mechanisms remains unclear. The present study aimed to explore the possoble anti-diabetic mechanisms of 14 probiotics.
C57BL/Ks mice were normal group. The db/db mice were randomized into five groups: model group, metformin group, liraglutide group, low-dose and high-dose probiotic group. Biochemical parameters were determined by the respective assay kits. The levels of the short-chain fatty acids (SCFAs) and microbiota were respectively determined by gas chromatography and qRT-PCR. HE staining and immunofluorescence were used for histomorphological observation. Quantitative PCR and western-blot were determined the gene and protein expression of Bax, Bcl-2, Caspase-3 and PI3K/AKT.
Probiotics significantly improved blood glucose and blood lipid parameters, as well as the morphological changes of pancreas, liver and kidney. Probiotics improved the gut barrier function through increasing the levels of SCFA-producing bacteria and SCFAs as well as the expression of claudin-1 and mucin-2, and decreasing Escherichia coli and LPS level. In additon, probiotics enhanced insulin secretion through glucose-triggered GLP-1 secretion by upregulating G protein-coupled receptor 43/41 (GPR43/41), proglucagon and proconvertase 1/3 activity. Forthermore, probiotics protected pancreas against apoptosis, which may be dependent on the upregulation of PI3K/AKT pathway.
The anti-diabetic effect of 14 probiotics in db/db mice seem to be related to an increase of SCFA-producing bacteria, the improvement of intestinal barrier function and the upregulation of GLP-1 production, and indicate these probiotics might be a good candidate to prevent and treat diabetes.
Innate immunity plays a crucial role in the response to sterile inflammation such as liver ischemia/reperfusion (I/R) injury. The initiation of liver I/R injury results in the release of ...damage‐associated molecular patterns, which trigger an innate immune and inflammatory cascade through pattern recognition receptors. Neutrophils are recruited to the liver after I/R and contribute to organ damage and innate immune and inflammatory responses. Formation of neutrophil extracellular traps (NETs) has been recently found in response to various stimuli. However, the role of NETs during liver I/R injury remains unknown. We show that NETs form in the sinusoids of ischemic liver lobes in vivo. This was associated with increased NET markers, serum level of myeloperoxidase–DNA complexes, and tissue level of citrullinated‐histone H3 compared to control mice. Treatment with peptidyl‐arginine‐deiminase 4 inhibitor or DNase I significantly protected hepatocytes and reduced inflammation after liver I/R as evidenced by inhibition of NET formation, indicating the pathophysiological role of NETs in liver I/R injury. In vitro, NETs increase hepatocyte death and induce Kupffer cells to release proinflammatory cytokines. Damage‐associated molecular patterns, such as High Mobility Group Box 1 and histones, released by injured hepatocytes stimulate NET formation through Toll‐like receptor (TLR4)‐ and TLR9‐MyD88 signaling pathways. After neutrophil depletion in mice, the adoptive transfer of TLR4 knockout or TLR9 knockout neutrophils confers significant protection from liver I/R injury with a significant decrease in NET formation. In addition, we found inhibition of NET formation by the peptidyl‐arginine‐deiminase 4 inhibitor and that DNase I reduces High Mobility Group Box 1 and histone‐mediated liver I/R injury. Conclusion: Damage‐associated molecular patterns released during liver I/R promote NET formation through the TLR signaling pathway. Development of NETs subsequently exacerbates organ damage and initiates inflammatory responses during liver I/R. (Hepatology 2015;62:600–614
Identifying an atom's local crystal structure is one crucial step in many atomistic simulation analyses. However, many traditional methods are available to only a few limited types of structures, and ...their performance often relies on manually determined parameters, which may lead to poor classification results in complex material systems. Machine learning models can enhance accuracy and generalizability, but they typically require large amounts of data and computation. This issue could be more severe for deep-learning-based frameworks, especially when confronted with unfamiliar crystal structures. To address this challenge, we propose a lightweight and extendable stacked structure (LESS) classifier, which adopts bond orientational order parameters as features and assembles several efficient machine learning methods as based models. The LESS classifier can recognize a variety of crystal structures, e.g., amorphous, mono, and binary structures, with over 98.8% accuracy on our validation data set, outperforming many current methods even including some deep-learning methods. Our model can also conduct probabilistic classification that aids in the interpretation of atomic structures in complicated environments such as heterogeneous interfaces. Furthermore, when exposed to a completely unknown crystal structure, the LESS framework can efficiently incorporate this new knowledge with generative sampled data from the current model. Overall, our model exhibits great potential as an accurate and flexible atomic structure identification tool featuring high efficiency in both learning and retraining.
This study reports a facile method for the synthesis of multi-enzyme co-embedded organic-inorganic hybrid nanoflowers, using glucose oxidase (GOx) and horseradish peroxidase (HRP) as the organic ...components, and Cu3(PO4)2 · 3H2O as the inorganic component. The synthesized nanoflowers enable the combination of a two-enzyme cascade reaction in one step, in which the GOx component of the nanoflowers oxidizes glucose to generate H2O2, which then reacts with the adjacent HRP component on the nanoflowers to oxidize the chromogenic substrates, resulting in an apparent color change. Given the close proximity of the two enzyme components in a single nanoflower, this novel sensor greatly reduces the diffusion and decomposition of H2O2, and greatly enhances the sensitivity of glucose detection. Thus, the obtained multi-enzyme co-embedded organic-inorganic hybrid nanoflowers can be unquestionably used as highly sensitive colorimetric sensors for the detection of glucose. Notably, this work presents a very facile route for the synthesis of multi-enzyme co-embedded nanomaterials for the simultaneous catalysis of multi-step cascade enzymatic reactions. Furthermore, it has great potential for application in biotechnology, and biomedical and environmental chemistry.
Neutrophils trap and kill bacteria by forming highly decondensed chromatin structures, termed neutrophil extracellular traps (NETs). We previously reported that histone hypercitrullination catalyzed ...by peptidylarginine deiminase 4 (PAD4) correlates with chromatin decondensation during NET formation. However, the role of PAD4 in NET-mediated bacterial trapping and killing has not been tested. Here, we use PAD4 knockout mice to show that PAD4 is essential for NET-mediated antibacterial function. Unlike PAD4(+/+) neutrophils, PAD4(-/-) neutrophils cannot form NETs after stimulation with chemokines or incubation with bacteria, and are deficient in bacterial killing by NETs. In a mouse infectious disease model of necrotizing fasciitis, PAD4(-/-) mice are more susceptible to bacterial infection than PAD4(+/+) mice due to a lack of NET formation. Moreover, we found that citrullination decreased the bacterial killing activity of histones and nucleosomes, which suggests that PAD4 mainly plays a role in chromatin decondensation to form NETs instead of increasing histone-mediated bacterial killing. Our results define a role for histone hypercitrullination in innate immunity during bacterial infection.
A major challenge in the development of anion exchange membranes for fuel cells is the design and synthesis of highly stable (chemically and mechanically) conducting membranes. Membranes that can ...endure highly alkaline environments while rapidly transporting hydroxides are desired. Herein, we present a design using cross-linked polymer membranes containing ionic highways along charge-delocalized pyrazolium cations and homoconjugated triptycenes. These ionic highway membranes show improved performance. Specifically, a conductivity of 111.6 mS cm–1 at 80 °C was obtained with a low 7.9% water uptake and 0.91 mmol g–1 ion exchange capacity. In contrast to existing materials, ionic highways produce higher conductivities at reduced hydration and ionic exchange capacities. The membranes retain more than 75% of their initial conductivity after 30 days of an alkaline stability test. The formation of ionic highways for ion transport is confirmed by density functional theory and Monte Carlo studies. A single cell with platinum metal catalysts at 80 °C showed a high peak density of 0.73 W cm–2 (0.45 W cm–2 from a silver-based cathode) and stable performance throughout 400 h tests.
Soft and conformable wearable electronics require stretchable semiconductors, but existing ones typically sacrifice charge transport mobility to achieve stretchability. We explore a concept based on ...the nanoconfinement of polymers to substantially improve the stretchability of polymer semiconductors, without affecting charge transport mobility. The increased polymer chain dynamics under nanoconfinement significantly reduces the modulus of the conjugated polymer and largely delays the onset of crack formation under strain. As a result, our fabricated semiconducting film can be stretched up to 100% strain without affecting mobility, retaining values comparable to that of amorphous silicon. The fully stretchable transistors exhibit high biaxial stretchability with minimal change in on current even when poked with a sharp object. We demonstrate a skinlike finger-wearable driver for a light-emitting diode.
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