Research progress in biological activities and mechanisms of theabrownin

Tea is beneficial to human health, which is rich in tea pigments with important biological activities. Theabrownin, derived from theaflavins and thearubigins by oxidative polymerization, mainly distributes in semi-fermented oolong tea, and completely fermented black tea and dark tea. As a kind of macromolecular substance, theabrownin cannot be directly absorbed by the gut, but it can directly interact with intestinal microbiota to regulate and maintain the homeostasis of intestinal flora. Theabrownin has multiple physiological roles via modulating the gut microbiota, including inhibiting hepatic cholesterol production, promoting the catabolism of cholesterol and triglyceride, and promoting energy metabolism in adipose tissues, thereby improving lipid metabolism. Theabrownin can also directly influence the gut absorption of glucose to improve carbohydrate metabolism and maintain blood glucose homeostasis. Theabrownin plays an anti-tumor role by inducing apoptosis and regulating gene expression in tumor cells. Theabrownin also plays an anti-inflammatory role via participating in the regulation of the immune cell differentiation and the levels of inflammatory factors. This review summarizes the formation process, the extraction procedures, and the chemical structure of theabrownin, and reviews the effects and mechanisms of theabrownin on intestinal microbiota, lipid metabolism, blood glucose homeostasis, cancer and inflammation

Self-Assembly of Mitochondria-Specific Peptide Amphiphiles Amplifying the Lung Cancer Cell Death through Targeting the VDAC1-Hexokinase-II Complex

International audienceMitochondria-targeting peptides represent an emergent approach for cancer inhibition. Here supramolecular assemblies of novel amphiphilic cell-penetrating peptides for targeting cancer cells mitochondria are reported. The employed strategy aims at amplifying the apoptotic stimuli by weakening the mitochondrial VDAC1 (voltage-dependent anion channel-1)-hexokinase-II (HK-II) interaction. Peptide engineering is performed with the N-terminus of the HK-II protein, which binds to VDAC1. First, a designed positively-charged segment (pKV) is anchored to the specific 15 aminoacid sequence (MIASHLLAYFFTELN) to yield a cell-penetrating peptide (pHK-pKV). Second, a lipid chain (Pal) is conjugated to the N-terminus of pHK-pKV in order to enhance the intracellular delivery of the HK-II scaffold. The self-assembly properties of these two synthetic peptides are investigated by synchrotron small-angle X-ray scattering (BioSAXS) and cryogenic transmission electron (cryo-TEM) imaging, which evidence the formation of nanoassemblies of ellipsoid-like shapes. Circular dichroism (CD) spectroscopy demonstrates the induction of partial α-helical structures in the amphiphilic peptides. Confocal microscopy reveals the specific mitochondrial location of Pal-pHK-pKV assemblies in human non-small cell lung cancer (NSCLC) A549 cells. The cytotoxicity and apoptotic studies indicate the enhanced bioactivity of Pal-pHK-pKV self-assembled reservoirs, which cause massive A549 cell death with regard to pHK-pKV. Whereas the half maximum inhibitory concentration (IC 50) of the Pal-pHK-pKV peptide conjugates is 6.5 μM in the A549 cancer cell line, it is higher than 50 μM for healthy human mucosal epithelial cells such as the non-cancerous NCM460 cells. The results demonstrate the potential of self-assembled lipo-peptide (HK-II-derived) conjugates as a promising strategy in cancer therapy.

Determination of 13 Free Fatty Acids in Pheretima Using Ultra-Performance LC-ESI-MS

Abstract: A simple and rapid ultra-performance liquid chromatography-electrospray ionization mass spectrometry method for the simultaneous determination of thirteen free fatty acids (FFAs) in Pheretima has been developed and validated. Measurements for each FFA were linear over a wide range (0.05-3.95 μg mL −1 ) with good correlation coefficients (>0.99). The limit of detection and limit of quantification for all the fatty acids were below 26 and 78 ng mL −1 , respectively. The intra-and inter-assay precision and accuracy for the thirteen FFAs fell well within the predefined limits of acceptability. Satisfactory recoveries were in the range of 96-103%. Article: INTROCUDTION Pheretima has been well known for its wide therapeutic properties such as anti-inflammatory, anti-oxidative [1], anti-asthmatic, thrombolytic, reducing symptoms of the central nervous system decline including memory loss in traditional Chinese medicine (TCM) for over 2,000 years Although fatty acids have measurable absorbance in the range of 190-215 nm, the interference of most solvents is a limiting factor for sensitive detection when analyzed directly by liqui

How Users Search the Mobile Web: A Model for Understanding the Impact of Motivation and Context on Search Behaviors

Purpose: This study explores how search motivation and context influence mobile Web search behaviors. Design/methodology/approach: We studied 30 experienced mobile Web users via questionnaires, semi-structured interviews, and an online diary tool that participants used to record their daily search activities. SQLite Developer was used to extract data from the users' phone logs for correlation analysis in Statistical Product and Service Solutions (SPSS). Findings: One quarter of mobile search sessions were driven by two or more search motivations. It was especially difficult to distinguish curiosity from time killing in particular user reporting. Multi-dimensional contexts and motivations influenced mobile search behaviors, and among the context dimensions, gender, place, activities they engaged in while searching, task importance, portal, and interpersonal relations (whether accompanied or alone when searching) correlated with each other. Research limitations: The sample was comprised entirely of college students, so our findings may not generalize to other populations. More participants and longer experimental duration will improve the accuracy and objectivity of the research. Practical implications: Motivation analysis and search context recognition can help mobile service providers design applications and services for particular mobile contexts and usages. Originality/value: Most current research focuses on specific contexts, such as studies on place, or other contextual influences on mobile search, and lacks a systematic analysis of mobile search context. Based on analysis of the impact of mobile search motivations and search context on search behaviors, we built a multi-dimensional model of mobile search behaviors

A New SVM Multiclass Incremental Learning Algorithm

A new support vector machine (SVM) multiclass incremental learning algorithm is proposed. To each class training sample, the hyperellipsoidal classifier that includes as many samples as possible and pushes the outlier samples away is trained in the feature space. When the new samples are added to the classification system, the algorithm reuses the old classifiers that have nothing to do with the new sample classes. To be classified sample, the Mahalanobis distances are used to decide the class of classified sample. If the sample point is not surrounded by any hyperellipsoidal or is surrounded by more than one hyperellipsoidal, the membership is used to confirm its class. The experimental results show that the algorithm has higher performance in classification precision and classification speed

Construction of a New Fractional Chaotic System and Generalized Synchronization

In this paper a new dynamic system with integer and fractional order is investigated. It is shown that determining the effect of quadratic coefficients to the systematic structure can be converted to determining that of coefficients of the linear part. Under some parametric conditions, the system can produce chaotic attractors similar as Lorenz attractor. A constructive theorem is proposed for generalized synchronization related to the fractional-order chaotic system and an application of this new system is demonstrated

Optimization of Axial Symmetrical FGM Under the Transient-State Temperate Field

A numerical procedure for analyzing the temperature distribution in a hollow axisymmetric cylinder, made of functionally gradient material (FGM), was investigated. Based on the thermal elasticity theory and the arbitrary difference precise integration (ADPI) method, temperature distribution through the FGM cylinder in the ring section under a transient-state temperature field was developed and presented. A genetic algorithm (GA) was applied to the thermal stress optimal design of an FGM hollow cylinder, and as a result, the minimum thermal stress distribution in the FGM cylinder was obtained. A corresponding numerical procedure regarding to a ceramic-metal FGM cylinder was performed, and the computational results were discussed

How the Sodium Cations in Anode Affect the Performance of a Lithium-ion Battery

Large cations such as potassium ion (K+) and sodium ion (Na+) could be introduced into the lithium-ion (Li-ion) battery system during material synthesis or battery assembly. However, the effect of these cations on charge storage or electrochemical performance has not been fully understood. In this study, sodium ion was taken as an example and introduced into the lithium titanium oxide (LTO) anode through the carboxymethyl cellulose (CMC) binder. After the charge/discharge cycles, these ions doped into the LTO lattice and improved both the lithium-ion diffusivity and the electronic conductivity of the anode. The sodium ion’s high concentration (>12.9%), however, resulted in internal doping of Na+ into the LTO lattice, which retarded the transfer of lithium ions due to repulsion and physical blocking. The systematic study presented here shows that large cations with an appropriate concentration in the electrode would be beneficial to the electrochemical performance of the Li-ion battery