13 research outputs found
Emergency Evacuation Route Choice Based on Improved Ant Colony Algorithm
In order to explore the optimal route choice for emergency evacuation in the campus, we propose a novel route choice method based on brittle characteristics of campus system and improved ant colony algorithm. Both optimal and worst-case emergency evacuation routes are simulated in the campus of Ningbo University of Technology. From the simulation, the length of optimal and worse-case evacuation routes between the starting point and eight exits can be obtained by adjusting the importance value of trip distance and the degree of conformity, under the condition of static relative importance of pheromone concentration to graph G. The optimal route of emergency evacuation in the campus can be obtained when the importance of trip distance is above 5 and the degree of conformity is above 0.3; while the worse-case route is obtained with the importance of trip distance above 5 and the degree of conformity below 0.5
Analytic study on long wave transformation over a seamount with a pit
In this paper, an analytic solution is derived for linear long waves scattering over a submarine seamount landform with a pit. The seamount is axisymmetric with a pit on the top. The water depth is defined by a trinomial function in the radial direction. The governing linear shallow water equation for long waves is expressed in the polar coordination, which is solved through separation of variables. As the topography is axisymmetric, solutions can be written as Fourier-cosine series. Waves over the seamount are expressed using Frobenius series expansion, while the water surface elevation in the outer region is expressed as Fourier-Bessel series, and the final solution is obtained by matching them at the conjunction. The solution can be degenerated into the previous analytic solutions for waves propagation over an axisymmetric pit or a submerged hump by adjusting the topography parameters
Comparative Transcript Profiling of Resistant and Susceptible Tea Plants in Response to Gray Blight Disease
Gray blight disease stands as one of the most destructive ailments affecting tea plants, causing significant damage and productivity losses. However, the dynamic roles of defense genes during the infection of gray blight disease remain largely unclear, particularly concerning their distinct responses in resistant and susceptible cultivars. In the pursuit of understanding the molecular interactions associated with gray blight disease in tea plants, a transcriptome analysis unveiled that 10,524, 17,863, and 15,178 genes exhibited differential expression in the resistant tea cultivar (Yingshuang), while 14,891, 14,733, and 12,184 genes showed differential expression in the susceptible tea cultivar (Longjing 43) at 8, 24, and 72 h post-inoculation (hpi), respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses highlighted that the most up-regulated genes were mainly involved in secondary metabolism, photosynthesis, oxidative phosphorylation, and ribosome pathways. Furthermore, plant hormone signal transduction and flavonoid biosynthesis were specifically expressed in resistant and susceptible tea cultivars, respectively. These findings provide a more comprehensive understanding of the molecular mechanisms underlying tea plant immunity against gray blight disease
Abstract 194: E-selectin mediates targeted delivery of mesenchymal stem cells to tumor
Abstract
Objectives. Tumor tissue produces abundant stromal cell-derived factor-1α (SDF-1α/CXCL12) that promotes recruitment of circulating stem/progenitor cells. We have recently found that SDF-1α induces elevated expression of CD162 and CD44, both are E-selectin ligands, on luminal endothelial cells lining capillaries. We thus postulate that highly expressed E-selectin ligands on tumor endothelium can serve as docking molecules to mediate specific homing of E-selectin-expressing circulating stem cells to tumor tissues. Here, we tested the role of E-selectin in mediating and facilitating homing of mesenchymal stem cells (MSC), which are modified to overexpress E-selectin, to SDF-1α−rich melanoma tissue.
Methods. MSC from C57 BL6 and E-selectin-/- mice were enriched by culturing bone marrow cells in MesenCultTM medium. MSC were genetically labeled with luciferase (Luc2) or GFP in vitro. MSC from C57 BL6 mice were engineered to stably overexpress E-selectin (E-selectin+). Human melanoma cells were engineered to overexpress SDF-1α. 2 x 10^6 SDF-1α+/melanoma cells were pre-engrafted into NSG mice via tail-vein or subcu to form lung metastatic foci or skin melanoma, respectively. After 7-10 days, 1 x 10^6 E-selectin+ or E-selectin-/- MSC were injected into tumor-bearing mice through tail-vein or subcu, respectively. Homing of injected MSC to melanoma was assessed at various time points by IVIS (for Luc2+/MSC) and flow cytometry (for GFP+/MSC), respectively.
Results. There were significantly increased numbers of engineered E-selectin-overexpressing MSC homing to melanoma tissues via systemic and local approaches, compared to control MSC or E-selectin-/-/MSC (p<0.05).
Conclusions. E-selectin is an effective adhesion molecule in mediating tumor selective homing of MSC. Our study provides a useful method for targeted delivery of cells to tumor and may have therapeutic potential for developing stem cell-based cancer treatment.
Citation Format: Cuixia Yang, Danjuan Li, Bo Wang, Omaida C. Velazquez, Zhao-Jun Liu. E-selectin mediates targeted delivery of mesenchymal stem cells to tumor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 194. doi:10.1158/1538-7445.AM2014-194</jats:p
Emergency Evacuation Route Choice Based on Improved Ant Colony Algorithm
In order to explore the optimal route choice for emergency evacuation in the campus, we propose a novel route choice
method based on brittle characteristics of campus system and improved ant colony algorithm. Both optimal and
worst-case emergency evacuation routes are simulated in the campus of Ningbo University of Technology. From the
simulation, the length of optimal and worse-case evacuation routes between the starting point and eight exits can be
obtained by adjusting the importance value of trip distance and the degree of conformity, under the condition of static
relative importance of pheromone concentration to graph G. The optimal route of emergency evacuation in the
campus can be obtained when the importance of trip distance is above 5 and the degree of conformity is above 0.3;
while the worse-case route is obtained with the importance of trip distance above 5 and the degree of conformity
below 0.5
Recent advances in small incision lenticule extraction (SMILE)-derived refractive lenticule preservation and clinical reuse
Small incision lenticule extraction (SMILE) has become one of the mainstream refractive surgeries in recent years, with satisfactory efficacy, safety, and predictability. SMILE-derived refractive lenticule, the byproduct of the surgery, holds great potential in clinical practice given its easy access and good biocompatibility. Numerous studies have been published to describe its applications in refractive correction, corneal ectasia diseases, and corneal defects. The feasibility and safety were validated in both animal models and clinical studies. Moreover, the preservation method is also crucial for its further promotion and application. Novel techniques are also evaluated and applied in lenticule preservation. We covered the recent advances in the preservation of corneal stromal lenticules and their clinical reuse in this review
Long-read ChIA-PET for base-pair-resolution mapping of haplotype-specific chromatin interactions.
Chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) is a robust method for capturing genome-wide chromatin interactions. Unlike other 3C-based methods, it includes a chromatin immunoprecipitation (ChIP) step that enriches for interactions mediated by specific target proteins. This unique feature allows ChIA-PET to provide the functional specificity and higher resolution needed to detect chromatin interactions, which chromosome conformation capture (3C)/Hi-C approaches have not achieved. The original ChIA-PET protocol generates short paired-end tags (2 × 20 base pairs (bp)) to detect two genomic loci that are far apart on linear chromosomes but are in spatial proximity in the folded genome. We have improved the original approach by developing long-read ChIA-PET, in which the length of the paired-end tags is increased (up to 2 × 250 bp). The longer PET reads not only improve the tag-mapping efficiency but also increase the probability of covering phased single-nucleotide polymorphisms (SNPs), which allows haplotype-specific chromatin interactions to be identified. Here, we provide the detailed protocol for long-read ChIA-PET that includes cell fixation and lysis, chromatin fragmentation by sonication, ChIP, proximity ligation with a bridge linker, Tn5 tagmentation, PCR amplification and high-throughput sequencing. For a well-trained molecular biologist, it typically takes 6 d from cell harvesting to the completion of library construction, up to a further 36 h for DNA sequencing andreads. Nat Protoc 2017 May; 12(5):899-915
CTCF-Mediated Human 3D Genome Architecture Reveals Chromatin Topology for Transcription.
Spatial genome organization and its effect on transcription remains a fundamental question. We applied an advanced chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) strategy to comprehensively map higher-order chromosome folding and specific chromatin interactions mediated by CCCTC-binding factor (CTCF) and RNA polymerase II (RNAPII) with haplotype specificity and nucleotide resolution in different human cell lineages. We find that CTCF/cohesin-mediated interaction anchors serve as structural foci for spatial organization of constitutive genes concordant with CTCF-motif orientation, whereas RNAPII interacts within these structures by selectively drawing cell-type-specific genes toward CTCF foci for coordinated transcription. Furthermore, we show that haplotype variants and allelic interactions have differential effects on chromosome configuration, influencing gene expression, and may provide mechanistic insights into functions associated with disease susceptibility. 3D genome simulation suggests a model of chromatin folding around chromosomal axes, where CTCF is involved in defining the interface between condensed and open compartments for structural regulation. Our 3D genome strategy thus provides unique insights in the topological mechanism of human variations and diseases. Cell 2015 Dec 17; 163(7):1611-27