The numerical operator method to the real time dynamics of currents through the nanostructures with different topologies

We present the numerical operator method designed for the real time dynamics of currents through nanostructures beyond the linear response regime. We apply this method to the transient and stationary currents through nanostructures with different topologies, e.g., the flakes of square and honeycomb lattices. We find a quasi-stationary stage with a life proportional to the flake size in the transient currents through the square flakes, but this quasi-stationary stage is destroyed in the presence of disorder. However, there is no quasi-stationary stage in the transient currents through the honeycomb flakes, showing that the transient current depends strongly upon the topologies of the nanostructures. We also study the stationary current by taking the limit of the current at long times. We find that the stationary current through a square flake increases smoothly as the voltage bias increasing. In contrast, we find a threshold voltage in the current-voltage curve through a honeycomb flake, indicating a gap at the Fermi energy of a honeycomb flake.Comment: 13 pages, 4 figure

Effects of income and residential area on survival of patients with head and neck cancers following radiotherapy: working age individuals in Taiwan

Objectives The five-year survival rate of head and neck cancer (HNC) after radiotherapy (RT) varies widely from 35% to 89%. Many studies have addressed the effect of socioeconomic status and urban dwelling on the survival of HNC, but a limited number of studies have focused on the survival rate of HNC patients after RT. Materials and methods During the period of 2000–2013, 40,985 working age individuals (20  medium income group > low income group and northern > central > southern > eastern Taiwan. Patients with moderate income levels had a 36.9% higher risk of mortality as compared with patients with high income levels (hazard ratio (HR) = 1.369; p < 0.001). Patients with low income levels had a 51.4% greater risk of mortality than patients with high income levels (HR = 1.514, p < 0.001). Conclusion In Taiwan, income and residential area significantly affected the survival rate of HNC patients receiving RT. The highest income level group had the best survival rate, regardless of the geographic area. The difference in survival between the low and high income groups was still pronounced in more deprived areas

An efficient discrete element lattice Boltzmann model for simulation of particle-fluid, particle-particle interactions

In this study, an efficient Discrete Element Lattice Boltzmann Model (DE-LBM) is introduced to simulate mechanical behaviours of multiphase systems involving particle-fluid and particle-particle interactions. The LBM is based on the Multiple Relaxation Time (MRT-LBM) formalism for the fluid phase and the Discrete Element Method for particle motions. A novel algorithm is developed for detecting the particle contact base on particle overlapping areas computed directly from the grid-based LBM data. This contact algorithm achieves the same accuracy in determining the particle contact as provided by the Hertz contact model but is far more efficient computationally. The DE-LBM coupling approach is also modified to unify the different schemes developed previously. A modified Verlet List method for updating the solid occupation fraction is proposed to further speed up the simulation. The new model is validated by a series of simulations including the single particle settling and well-known ‘Drafting, Kissing and Tumbling’ (DKT) phenomenon found in suspensions. The settling of a large number (2500) of particles in a still fluid is also simulated with predicted concentration profiles matching well the analytic solution. These applications demonstrate the potential of the present DE-LBM model as a powerful numerical tool for simulating multiphase particulate systems encountered in many engineering and science disciplines

Study on Evolvement Complexity in an Artificial Stock Market

An artificial stock market is established based on multi-agent . Each agent has a limit memory of the history of stock price, and will choose an action according to his memory and trading strategy. The trading strategy of each agent evolves ceaselessly as a result of self-teaching mechanism. Simulation results exhibit that large events are frequent in the fluctuation of the stock price generated by the present model when compared with a normal process, and the price returns distribution is L\'{e}vy distribution in the central part followed by an approximately exponential truncation. In addition, by defining a variable to gauge the "evolvement complexity" of this system, we have found a phase cross-over from simple-phase to complex-phase along with the increase of the number of individuals, which may be a ubiquitous phenomenon in multifarious real-life systems.Comment: 4 pages and 4 figure

Characterization and regulation of MT1‐MMP cell surface‐associated activity

Quantitative assessment of MT1‐MMP cell surface‐associated proteolytic activity remains undefined. Presently, MT1‐MMP was stably expressed and a cell‐based FRET assay developed to quantify activity toward synthetic collagen‐model triple‐helices. To estimate the importance of cell surface localization and specific structural domains on MT1‐MMP proteolysis, activity measurements were performed using a series of membrane‐anchored MT1‐MMP mutants and compared directly with those of soluble MT1‐MMP. MT1‐MMP activity (kcat/KM) on the cell surface was 4.8‐fold lower compared with soluble MT1‐MMP, with the effect largely manifested in kcat. Deletion of the MT1‐MMP cytoplasmic tail enhanced cell surface activity, with both kcat and KM values affected, while deletion of the hemopexin‐like domain negatively impacted KM and increased kcat. Overall, cell surface localization of MT1‐MMP restricts substrate binding and protein‐coupled motions (based on changes in both kcat and KM) for catalysis. Comparison of soluble and cell surface‐bound MT2‐MMP revealed 12.9‐fold lower activity on the cell surface. The cell‐based assay was utilized for small molecule and triple‐helical transition state analog MMP inhibitors, which were found to function similarly in solution and at the cell surface. These studies provide the first quantitative assessments of MT1‐MMP activity and inhibition in the native cellular environment of the enzyme.MT1‐MMP was stably expressed and a cell‐based FRET assay developed to quantify activity toward synthetic collagen‐model triple‐helices. Activity measurements were performed using a series of membrane‐anchored MT1‐MMP mutants and compared directly with those of soluble MT1‐MMP. Cell surface localization of MT1‐MMP was found to restrict substrate binding and protein‐coupled motions for catalysis. Small molecule and triple‐helical transition state analog MMP inhibitors were found to function similarly in solution and at the cell surface.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150520/1/cbdd13450.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150520/2/cbdd13450_am.pd

Assessing trends and predictors of tuberculosis in Taiwan

<p>Abstract</p> <p>Background</p> <p>Variety of environmental and individual factors can cause tuberculosis (TB) incidence change. The purpose of this study was to assess the characteristics of TB trends in the period 2004 - 2008 in Taiwan by month, year, gender, age, temperature, seasonality, and aborigines.</p> <p>Methods</p> <p>The generalized regression models were used to examine the potential predictors for the monthly TB incidence in regional and national scales.</p> <p>Results</p> <p>We found that (<it>i</it>) in Taiwan the average TB incidence was 68 per 100,000 population with mortality rate of 0.036 person^-1yr^-1, (<it>ii</it>) the highest TB incidence rate was found in eastern Taiwan (116 per 100,000 population) with the largest proportion of TB relapse cases (8.17%), (<it>iii</it>) seasonality, aborigines, gender, and age had a consistent and dominant role in constructing TB incidence patterns in Taiwan, and (<it>iv</it>) gender, time trend, and 2-month lag maximum temperature showed strong association with TB trends in aboriginal subpopulations.</p> <p>Conclusions</p> <p>The proposed Poisson regression model is capable of forecasting patterns of TB incidence at regional and national scales. This study suggested that assessment of TB trends in eastern Taiwan presents an important opportunity for understanding the time-series dynamics and control of TB infections, given that this is the typical host demography in regions where these infections remain major public health problems.</p

Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts