Data-Enabled Computational Multiscale Method in Materials Science and Engineering

In the Community of Computational Materials Science, One of the Challenges in Hierarchical Multiscale Modeling is Information-Passing from One Scale to Another, especially from the Molecular Model to the Continuum Model. a Machine-Learning-Enhanced Approach, Proposed in This Paper, Provides an Alternative Solution. in the Developed Hierarchical Multiscale Method, Molecular Dynamics Simulations in the Molecular Model Are Conducted First to Generate Datasets, Which Represents Physical Phenomena at the Nanoscale. the Datasets Are Then Used to Train Neural Networks for Failure Classification and Stress Regressions. Finally, the Well-Trained Learning Machines Are Implemented in the Continuum Model to Study the Mechanical Behaviors of Materials at the Macroscale. Randomized Neural Networks Are Employed Due to their Computational Efficiency

Reviews on Mechanisms of In Vitro

It is widely acknowledged that the excessive reactive oxygen species (ROS) or reactive nitrogen species (RNS) induced oxidative stress will cause significant damage to cell structure and biomolecular function, directly or indirectly leading to a number of diseases. The overproduction of ROS/RNS will be balanced by nonenzymatic antioxidants and antioxidant enzymes. Polysaccharide or glycoconjugates derived from natural products are of considerable interest from the viewpoint of potent in vivo and in vitro antioxidant activities recently. Particularly, with regard to the in vitro antioxidant systems, polysaccharides are considered as effective free radical scavenger, reducing agent, and ferrous chelator in most of the reports. However, the underlying mechanisms of these antioxidant actions have not been illustrated systematically and sometimes controversial results appeared among various literatures. To address this issue, we summarized the latest discoveries and advancements in the study of antioxidative polysaccharides and gave a detailed description of the possible mechanisms

A Machine-Learning-Enhanced Hierarchical Multiscale Method for Bridging from Molecular Dynamics to Continua

In the Community of Computational Materials Science, One of the Challenges in Hierarchical Multiscale Modeling is Information-Passing from One Scale to Another, especially from the Molecular Model to the Continuum Model. a Machine-Learning-Enhanced Approach, Proposed in This Paper, Provides an Alternative Solution. in the Developed Hierarchical Multiscale Method, Molecular Dynamics Simulations in the Molecular Model Are Conducted First to Generate a Dataset, Which Represents Physical Phenomena at the Nanoscale. the Dataset is Then Used to Train a Material Failure/defect Classification Model and Stress Regression Models. Finally, the Well-Trained Models Are Implemented in the Continuum Model to Study the Mechanical Behaviors of Materials at the Macroscale. Multiscale Modeling and Simulation of a Molecule Chain and an Aluminum Crystalline Solid Are Presented as the Applications of the Proposed Method. in Addition to Support Vector Machines, Extreme Learning Machines with Single-Layer Neural Networks Are Employed Due to their Computational Efficiency

Arabidopsis IAR4 Modulates Primary Root Growth Under Salt Stress Through ROS-Mediated Modulation of Auxin Distribution

High salinity is one of the major environmental stresses that plants encounter. Roots are the initial and direct organs to perceive the signal. However, how plant roots perceive and respond to salinity at the molecular and physiological levels is still poorly understood. Here, we report that IAA-CONJUGATE-RESISTANT 4 (IAR4) plays a key role in primary root growth under salt stress conditions. Mutation of IAR4 led to increased sensitivity to salt stress conditions, with strongly inhibited primary root growth and reduced survival rate in two iar4 mutant alleles. iar4 mutants accumulated greater Na+ and exhibited a greater Na+/K+ ratio under NaCl treatment. In addition, more reactive oxygen species (ROS) accumulated in the iar4 mutants due to reduced ROS scavenging. NaCl treatment greatly suppressed the expression levels of ProPIN1:PIN1-GFP, ProPIN2:PIN2-GFP, ProPIN3:PIN3-GFP, and ProDR5:GFP, and suppressed root meristem activity in iar4. GSH or auxin treatment greatly recovered the PIN expression, auxin distribution and primary root growth in the iar4 mutants, suggesting ROS is a vital mediator between salt stress and auxin response. Our data support a model in which IAR4 integrates ROS and auxin pathways to modulate primary root growth under salinity stress conditions, by regulation of PIN-mediated auxin transport

Container CT scanner: a solution for modular emergency radiology department during the COVID-19 pandemic

During the coronavirus disease 2019 (COVID-19) pandemic period, container computed tomography (CT) scanners were developed and used for the first time in China to perform CT examinations for patients with clinically mild to moderate COVID-19 who did not need to be hospitalized for comprehensive treatment, but needed to be isolated in Fangcang shelter hospitals (also known as makeshift hospitals) to receive some supportive treatment. The container CT is a multidetector CT scanner installed within a radiation-protected stand-alone container (a detachable lead shielding room) that is deployed outside the makeshift hospital buildings. The container CT approach provided various medical institutions with the solution not only for rapid CT installation and high adaptability to site environments, but also for significantly minimizing the risk of cross-infection between radiological personnel and patients during CT examination in the pandemic. In this article, we described the typical setup of a container CT and how it worked for chest CT examinations in Wuhan city, the epicenter of COVID-19 outbreak

TNF-α and IFN-γ synergistically inhibit the repairing ability of mesenchymal stem cells on mice colitis and colon cancer.

BACKGROUND(#br)Mesenchymal stem cells (MSCs) can be efficiently recruited to wound, inflammatory and tumor sites to repair and regenerate tissue. However, its role in colitis and colitis associated colon cancer is still controversial. This study was designed to evaluate the role and mechanisms of inflammatory cytokines-activated-MSCs in mice colitis and colon cancer.(#br)METHODS(#br)We selected two well-characterized pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), to expand the inflammatory microenvironment of MSCs. The severity of colitis and colon cancer was evaluated by measuring colon length, Myeloperoxidase (MPO) activity, Hematoxylin-eosin staining, Western Blot, Immunohistochemistry and Immunofluorescence. These techniques were also performed to analyze the mechanisms of inflammatory cytokines-activated-MSCs in mice colitis and colon cancer. Real-time PCR and Enzyme-linked Immunosorbent Assay (ELISA) were used to measure the secretion of pro-inflammatory factors.(#br)RESULTS(#br)We found that the incubation of MSCs with TNF-α and IFN-γ aggravates colitis, where high levels of pro-inflammatory factors, such as interleukin (IL)-17, IL-8, IL-12, IL-1β, transforming growth factor (TGF)-β, TNF-α and IFN-γ, were secreted. Furthermore, this phenomenon was associated with the activation of the nuclear factor-kappa-B (NF-κB)/Signal transducer and activator of transcription three (STAT3) pathway. In addition, our study demonstrated that TNF-α and IFN-γ pretreated MSCs synergistically exacerbated mice colon cancer, which was closely associated with angiogenesis.(#br)CONCLUSIONS(#br)Taken together, these results indicate that TNF-α and IFN-γ pretreatment effectively inhibited the repair ability of MSCs and accelerated inflammation and tumor progression involving NF-κB/STAT3 pathway and angiogenesis-related factors

Effects of Differently Processed Carrots on Ulcerative Colitis in Mice

The incidence of ulcerative colitis (UC) has been increasing in recent years. Due to the limitations of traditional drug therapies for UC, natural foods that can prevent this disease and alleviate its symptoms are becoming a research hot topic, but the effects of processing methods on their activity remain unknown. Therefore, the effects of three different processing methods (pulping, high-temperature cooking, and fermentation) on carotenoid and dietary fiber contents as well as carotenoid bioaccessibility in carrots were explored in this study. C57BL/6J mice were used to create a mouse model of UC induced by dextran sulfate sodium (DSS) and the mice received dietary intervention with freeze dried powder of carrots (5.05%, on a dry mass basis) for 14 days. Body mass change, disease activity index (DAI) and colon parameters (length, pathology, inflammatory factors, oxidative stress level, goblet cell number, tight junction protein expression, and short-chain fatty acid content) were analyzed to evaluate the effects of three differently processed carrots on UC. The results showed compared with pulping, high-temperature cooking and fermentation significantly decreased the soluble, insoluble and total dietary fiber contents of carrots (P < 0.05), increased the bioaccessibility of carotenoids (P < 0.05), while fermentation significantly increased the proportion of soluble dietary fiber in total dietary fiber (P < 0.05). Compared with the model group, all processed carrots could significantly inhibit the change of body mass loss and DAI (P < 0.05), decrease the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 (P < 0.05), increase the level of IL-10 (P < 0.05), and up-regulate the expression of tight junction proteins (ZO-1, claudin-1, and occludin) (P < 0.05). High-temperature cooked or fermented carrots could significantly alleviate colon shortening (P < 0.05), and relieve the pathological damage of colon tissue (P < 0.05). Meanwhile, fermented carrots could significantly inhibit the production of malondialdehyde (MDA) (P < 0.05), improve the decrease in the number of goblet cells (P < 0.05), increase the level of butyric acid (P < 0.05) and possess the best inhibitory effect on IL-6 production. In summary, differently processed carrots could ameliorate ulcerative colitis to different extends, the most pronounced effect being observed with fermented carrots

Preparation and catalytic property of carbon nanotubes supported Pt and Ru nanoparticles for hydrogenation of aldehyde and substituted acetophenone in water

Pt and Ru nanoparticles are deposited on carbon nanotubes via a simple wet impregnation method using aqueous solutions of platinum and ruthenium salts to prepare the supported catalysts of Pt/CNTs (nominal load 5 wt%) and Ru/CNTs (nominal load 10 wt%). The catalysts are characterized by XRD, XPS, BET and TEM data and tested for the hydrogenation of aldehyde and substituted acetophenone using pure water as the sole solvent. The reaction conditions are well optimized through the hydrogenation of p-methoxybenzaldehyde and acetophenone. These catalysts exhibit high activity for the hydrogenation of aldehydes and ketones. Many aldehydes and ketones can be efficiently converted to the corresponding alcohols in the presence of Pt/CNTs and Ru/CNTs. The use of water as solvent makes this catalytic system environmental-friendly.

Energy loss enhancement of very intense proton beams in dense matter due to the beam-density effect

Thoroughly understanding the transport and energy loss of intense ion beams in dense matter is essential for high-energy-density physics and inertial confinement fusion. Here, we report a stopping power experiment with a high-intensity laser-driven proton beam in cold, dense matter. The measured energy loss is one order of magnitude higher than the expectation of individual particle stopping models. We attribute this finding to the proximity of beam ions to each other, which is usually insignificant for relatively-low-current beams from classical accelerators. The ionization of the cold target by the intense ion beam is important for the stopping power calculation and has been considered using proper ionization cross section data. Final theoretical values agree well with the experimental results. Additionally, we extend the stopping power calculation for intense ion beams to plasma scenario based on Ohm's law. Both the proximity- and the Ohmic effect can enhance the energy loss of intense beams in dense matter, which are also summarized as the beam-density effect. This finding is useful for the stopping power estimation of intense beams and significant to fast ignition fusion driven by intense ion beams