Automatic Multiscale Method of Building up a Cross-linked Polymer Reaction System: Bridging SMILES to the Multiscale Molecular Dynamics Simulation.

An automatic method is introduced to generate the initial configuration and input file from SMILES for multiscale molecular dynamics (MD) simulation of cross-linked polymer reaction systems. Inputs are a modified version of SMILES of all the components and conditions of coarse-grained (CG) and all-atom (AA) simulations. The overall process comprises the following steps: (1) Modified SMILES inputs of all the components are converted to 3-dimensional coordinates of molecular structures. (2) Molecular structures are mapped to the coarse-grained scale, followed by a CG reaction simulation. (3) CG beads are backmapped to the atomic scale after the CG reaction. (4) An AA productive run is finally performed to analyze volume shrinkage, glass transition, and atomic detail of network structure. The method is applied to two common epoxy resin reactions, that is, the cross-linking process of DGEVA (diglycidyl ether of vanillyl alcohol) and DHAVA (dihydroxyaminopropane of vanillyl alcohol) and that of DGEBA (diglycidyl ether of bisphenol A) and DETA (diethylenetriamine). These components form network structures after the CG cross-linking reaction and are then backmapped to calculate properties in the atomic scale. The result demonstrates that the method can accurately predict volume shrinkage, glass transition, and all-atom structure of cross-linked polymers. The method bridges from SMILES to MD simulation trajectories in an automatic way, which shortens the time of building up cross-linked polymer reaction model and suitable for high-throughput computations.

Mechanism for Topology Selection of Isomeric Two-Dimensional Covalent Organic Frameworks.

The mechanism of growth of one of the competitive topologies for covalent organic frameworks with constitutional isomers is poorly understood. Herein, we employ molecular dynamics to study the isoenergetic assembly of the rhombic square (sql) and Kagome lattice (kgm). The concentration, solvent conditions, and the reversibility of chemical reactions are considered by means of an Arrhenius two-state model to describe the reactions. High concentrations and poor solvent both result in sql, agreeing well with recent experiments. Moreover, the high reversibility of reactions gives rise to sql, while the low reversibility leads to kgm, suggesting a new way of regulating the topology. Our analyses support that the nucleation of isomers influenced by experimental conditions is responsible for the selection of topologies, which improves understanding of the control of topology. We also propose a strategy in which a two-step growth can be exploited to greatly improve the crystallinity of kgm.

Effect of feed restriction on the intestinal microbial community structure of growing ducks.

In poultry, feed restriction is common feeding management to limit poultry nutrients intake so that poultry only intake the essential energy, meeting the basic need of growth and development. Our study investigated whether feeding restriction affects the diversity of the intestinal microbiota of growing breeding ducks. In this research, the 60-120-day-old ducks were raised in restricted and free-feeding groups. After slaughtering, the carcass traits and the cecal contents were collected for 16S rRNA sequencing analysis. After feeding restriction, the growth rate of ducks was limited, the weight and rate of abdominal fat decreased, and the rate of chest and leg muscles increased. In addition, feeding restriction can also change the diversity of intestinal microorganisms in breeding ducks, such as the increase of Firmicutes abundance and the decrease of Bacteroidetes abundance. After analyzing of correlation, significant correlations between gut microbiota and carcass phenotypes were found. The results indicated that gut microbiota might be involved in the life activities associated with phenotypic changes. This study proved the effect of feeding methods on the intestinal microbiota of ducks, providing a theoretical basis of the microbial angle for raising ducks in a feeding-restricted period.

Lysin Motif (LysM) Proteins: Interlinking Manipulation of Plant Immunity and Fungi.

The proteins with lysin motif (LysM) are carbohydrate-binding protein modules that play a critical role in the host-pathogen interactions. The plant LysM proteins mostly function as pattern recognition receptors (PRRs) that sense chitin to induce the plant's immunity. In contrast, fungal LysM blocks chitin sensing or signaling to inhibit chitin-induced host immunity. In this review, we provide historical perspectives on plant and fungal LysMs to demonstrate how these proteins are involved in the regulation of plant's immune response by microbes. Plants employ LysM proteins to recognize fungal chitins that are then degraded by plant chitinases to induce immunity. In contrast, fungal pathogens recruit LysM proteins to protect their cell wall from hydrolysis by plant chitinase to prevent activation of chitin-induced immunity. Uncovering this coevolutionary arms race in which LysM plays a pivotal role in manipulating facilitates a greater understanding of the mechanisms governing plant-fungus interactions.

Determination and Comparison of Short-Chain Fatty Acids in Serum and Colon Content Samples: Alzheimer's Disease Rat as a Case Study.

Short-chain fatty acids (SCFAs) are the main microbial fermentation products from dietary fibers in the colon, and it has been speculated that they play a key role in keeping healthy in the whole-body. However, differences in SCFAs concentration in the serum and colon samples had attracted little attention. In this study, we have optimized the extract and analysis methods for the determination of ten SCFAs in both serum and colon content samples. Methanol and acetonitrile were chosen for extraction of SCFAs from serum and colon content samples, respectively. Biological samples were collected from Alzheimer's disease rats treated by extract of Schisandra chinensis (Turcz.) Baill (SC-extract) were taken as research objects. The results showed that, the relative peak intensities of SCFAs in the colon content from all groups were quite similar, and the trend was identical in the serum samples. Compared with the values in humans, the ratio of ten SCFAs in rat's colon was similar, while the percent of acetate in rat's serum was significantly higher. For therapy of Alzheimer's disease (AD), SC-extract decreased the concentration of butyrate, 3-Methyvalerate, and caproate in the serum samples towards the trend of normal rats. This study may help our understanding of how SCFAs are transported across colonic epithelium in healthy and diseased organisms.

Photodynamic therapy combined with surgical management of extensive anogenital condylomatosis in a patient with systemic lupus erythematosus.

Infections with human papillomavirus in the anogenital area result in warty, papillary, and condylomatous lesions. The giant anogenital wart is relatively uncommon. Treatment of giant wart is challenging, especially in the immunosuppressive population. Here, a patient with systemic lupus erythematosis had extensive, fast-growing, recurrent anogenital condylomatosis shaped as giant cauliflowers. We reported this case and the successful treatment of photodynamic therapy combined with surgical management. It provided the feasibility for surgical ablation combined with ALA-PDT performed for these kinds of challenging cases.

[Effects of Arsenic Trioxide on K562 Cell Proliferation and Its Mechanisms].

OBJECTIVE: To investigate the effects of arsenic trioxide (As2O3) on K562 cell proliferation by regulating cell cycle protein D1 and cyclin-dependent kinase inhibitor p27kip1. METHODS: MTT was used to detect the effect of As2O3 on K562 cell proliferation, so as to screen out the appropriate drug concentration. Furthermore, the K562 cell apoptosis was observed by microscopy. The expression of CyclinD1 and p27kip1 in K562 cells treated with As2O3 was analyzed by reverse transcription-polymerase chain reaction(RT-PCR), immunohistochemistry and Western blot. RESULTS: As2O3 could inhibit the proliferation of K562 cells in a dose- and time- dependent manner (r= 0.967). And the apoptosis cell number in As2O3 group was significantly higher than that in the control group(P<0.05). As2O3 could markedly inhibit the expression of CyclinD1 in K562 cells(P<0.05), but the expression of P27kip1 was not significantly changed after As2O3 treatment. CONCLUSIONS: As2O3 can induce K562 cell apoptosis and inhibit K562 cell proliferation by regulating the expression of CyclinD1.

[Mannan-Binding Lectin Inhibits Candida Albicans-Induced DC Maturation and Cytokine Secretion].

OBJECTIVE: To investigate the effects of mannan-binding lectin (MBL) on the maturation and cytokine secretion of human dendritic cells (DC) induced by Candida albicans (C. albicans). METHODS: The plastic-adherent mononuclear cells were prepared from the blood of healthy adult volunteers. The human peripheral blood mononuclear cells-derived dendritic cells (MNC-DC) were induced by 5-day-culture in medium supplemented with rhGM-CSF and rhIL-4, and then cultured for 2 days in presence or absence of C. albicans at varying concentration of human MBL ranging from 1 to 20 mg/L. DC's shape and characters were observed under inverted microscopy, the expression of CD83 and CD86 on DC was analyzed by FACS. The levels of TNF-α and IL-6 were detected by ELISA. FACS also was used to investigate the interaction of MBL with immature DC(imDC) and C. albicans. Western blot was used to detect C. albicans-induced IκBα phosphorylation and p65/NF-κB translocation in DC. RESULTS: MBL at higher concentrations (10-20 mg/L) down-regulated the expression of CD83 and CD86 on the monocyte-derived dentritic cells(MoDC) induced by C. albicans, and inhibited the production of TNF-α and IL-6 induced by C. albicans. FACS showed that MBL could not only bind to C. albicans but also bind to imDCs in a Ca2+-dependent manner. Western blot showed that MBL could decrease the phosphorylation of IκBα and the nuclear translocation of p65/ NF-κB. CONCLUSION: MBL may inhibit TNF-α and IL-6 production induced by C. albicans in DC through NF-κB signaling pathways, suggesting that MBL can play some roles in the regulation of C. albicans-induced immune response.

Laparoscopic versus open resection of gastric gastrointestinal stromal tumors.

The aims of this study were to explore whether laparoscopic surgical resections of gastric gastrointestinal stromal tumors (GISTs) would produce better perioperative and similar oncologic outcomes compared with open surgical resection in Chinese patients. Thirty-six gastric GISTs cases were divided into a minimally invasive laparoscopic group and open resection group, depending on the surgical approach that was used. The general preoperative information, operative time, incision length, intraoperative blood loss, postoperative time to first flatulence, postoperative complications, postoperative hospital stay, total hospitalization costs, and such follow-up data as recurrence, metastasis, and mortality rates were compared between two groups. Among the 36 gastric GISTs, 15 received laparoscopic surgical treatment (laparoscopy group, n=15), and 21 received routine open resection treatment (open resection group, n=21). The laparoscopy group and the open resection group showed statistically significant differences (P<0.05) in incision length (7.8±2.3 vs. 16.9±3.8 cm), postoperative time to first flatulence (3.8±1.3 vs. 5.1±2.1 d), postoperative hospitalization time (7.6±2.5 vs. 11.3±3.7 d), and total cost of hospitalization (RMB 28,239±5,521 vs. RMB 23,761±5,362). There were no statistically significant differences (P>0.05) between the laparoscopy group and the open resection group in operative time (147.8±59.3 vs. 139.2±62.1 min) and intraoperative blood loss (149.8±98.9 vs. 154.2±99.3 mL). Both groups had no postoperative complications, no recurrence and metastasis, and no postoperative mortality. There were no statistically significant differences between the two groups in postoperative complications, postoperative recurrence and metastasis, and postoperative mortality. In conclusion, compared with open resection, the laparoscopic resection of gastric GISTs offers the advantages of less trauma, faster recovery, and shorter hospital stay.