Modeling invasion of metastasizing cancer cells to bone marrow utilizing ecological principles

Abstract Background The invasion of a new species into an established ecosystem can be directly compared to the steps involved in cancer metastasis. Cancer must grow in a primary site, extravasate and survive in the circulation to then intravasate into target organ (invasive species survival in transport). Cancer cells often lay dormant at their metastatic site for a long period of time (lag period for invasive species) before proliferating (invasive spread). Proliferation in the new site has an impact on the target organ microenvironment (ecological impact) and eventually the human host (biosphere impact). Results Tilman has described mathematical equations for the competition between invasive species in a structured habitat. These equations were adapted to study the invasion of cancer cells into the bone marrow microenvironment as a structured habitat. A large proportion of solid tumor metastases are bone metastases, known to usurp hematopoietic stem cells (HSC) homing pathways to establish footholds in the bone marrow. This required accounting for the fact that this is the natural home of hematopoietic stem cells and that they already occupy this structured space. The adapted Tilman model of invasion dynamics is especially valuable for modeling the lag period or dormancy of cancer cells. Conclusions The Tilman equations for modeling the invasion of two species into a defined space have been modified to study the invasion of cancer cells into the bone marrow microenvironment. These modified equations allow a more flexible way to model the space competition between the two cell species. The ability to model initial density, metastatic seeding into the bone marrow and growth once the cells are present, and movement of cells out of the bone marrow niche and apoptosis of cells are all aspects of the adapted equations. These equations are currently being applied to clinical data sets for verification and further refinement of the models.http://deepblue.lib.umich.edu/bitstream/2027.42/112967/1/12976_2011_Article_309.pd

Complete Genome Sequence of the Citrobacter freundii Type Strain.

Citrobacter freundii is a species of facultative anaerobic Gram-negative bacteria of the family Enterobacteriaceae The complete genome is composed of a single chromosomal circle of 4,957,773 bp with a G+C content of 52%

When and why people misestimate future feelings: Identifying strengths and weaknesses in affective forecasting.

People try to make decisions that will improve their lives and make them happy, and to do so, they rely on affective forecasts-predictions about how future outcomes will make them feel. Decades of research suggest that people are poor at predicting how they will feel and that they commonly overestimate the impact that future events will have on their emotions. Recent work reveals considerable variability in forecasting accuracy. This investigation tested a model of affective forecasting that captures this variability in bias by differentiating emotional intensity, emotional frequency, and mood. Two field studies examined affective forecasting in college students receiving grades on a midterm exam (Study 1, N = 643), and U.S. citizens after the outcome of the 2016 presidential election (Study 2, N = 706). Consistent with the proposed model, participants were more accurate in forecasting the intensity of their emotion and less accurate in forecasting emotion frequency and mood. Overestimation of the effect of the event on mood increased over time since the event. Three experimental studies examined mechanisms that contribute to differential forecasting accuracy. Biases in forecasting intensity were caused by changes in perceived event importance; biases in forecasting frequency of emotion were caused by changes in the frequency of thinking about the event. This is the first direct evidence mapping out strengths and weaknesses for different types of affective forecasts and the factors that contribute to this pattern. (PsycINFO Database Record (c) 2019 APA, all rights reserved)

Generation of Innovative and Sparse Encoding Vectors for Broadcast Systems with Feedback

In the application of linear network coding to wireless broadcasting with feedback, we prove that the problem of determining the existence of an innovative encoding vector is NP-complete when the finite field size is two. When the finite field size is larger than or equal to the number of users, it is shown that we can always find an encoding vector which is both innovative and sparse. The sparsity can be utilized in speeding up the decoding process. An efficient algorithm to generate innovative and sparse encoding vectors is developed. Simulations show that the delay performance of our scheme with binary finite field outperforms a number of existing schemes in terms of average and worst-case delay.Comment: 5 pages, 4 figures, accepted for publication in the Proc. of IEEE ISIT 201

Longitudinal Trajectory of Adolescent Exposure to Community Violence and Depressive Symptoms among Adolescents and Young Adults: Understanding the Effect of Mental Health Service Usage

Research on the impact of exposure to community violence tends to define victimization as a single construct. This study differentiates between direct and indirect violence victimization in their association with mental health problems and mental health service use. This study includes 8947 individuals from four waves of the National Longitudinal Study of Adolescent to Adult Health and examines (1) whether sub-types of adolescent victimization are linked to depressive symptoms; (2) whether adolescent victimization is linked with mental health service use; and (3) the role of mental health service use in attenuating symptoms arising from victimizations. Adolescents witnessing community violence were more likely to experience depressive symptoms during adolescence but not during their young adulthood; direct exposure to violence during adolescence does not predict depressive symptoms in adolescence but does in adulthood. Use of mental health service mediates report of depressive symptoms for adolescent witnessing community violence