A toy model of fractal glioma development under RF electric field treatment

A toy model for glioma treatment by a radio frequency electric field is suggested. This low-intensity, intermediate-frequency alternating electric field is known as the tumor-treating-field (TTF). In the framework of this model the efficiency of this TTF is estimated, and the interplay between the TTF and the migration-proliferation dichotomy of cancer cells is considered. The model is based on a modification of a comb model for cancer cells, where the migration-proliferation dichotomy becomes naturally apparent. Considering glioma cancer as a fractal dielectric composite of cancer cells and normal tissue cells, a new effective mechanism of glioma treatment is suggested in the form of a giant enhancement of the TTF. This leads to the irreversible electroporation that may be an effective non-invasive method of treating brain cancer.Comment: Submitted for publication in European Physical Journal

The Roles Parents, Educators, Industry, Community, and Government Play in Growing and Sustaining the STEM Workforce

This study was conducted to shed light on the perspectives of business leaders regarding the roles that various stakeholder groups (parents, educators and schools, industry and community partners, and government) should play in establishing and maintaining the supply of skilled STEM workers. A field survey methodology was employed to survey over 1,000 business executives and managers located throughout the southeastern United States. Their responses to open-ended survey questions were analyzed using textual analysis with topic modeling to reveal probabilistic thematic coverage, explore factors that may lead to more STEM-capable graduates, and ultimately a sustained STEM workforce. Results indicate that business leaders envision roles for all key stakeholder groups and that finding a successful solution will require interaction among the stakeholder groups if we are to be successful in creating a sustained pipeline of STEM talent

What CEOs Have to Say: Insights on the STEM Workforce

Establishing and maintaining the supply of skilled STEM workers are issues that many businesses are currently facing. CEOs can provide unique perspectives on the roles of parents, educators and schools, industry and community partners, and government on this issue. To this end, a Qualtrics panel was used to survey 45 CEOs located in the state of Georgia in the southeastern United States. CEOs responded to open-ended questions that were later analyzed using topic modeling techniques to uncover the themes and the factors that have the potential to increase the number of STEM-capable graduates and, ultimately, a sustained STEM workforce. The results of this study indicate that CEOs perceive parents, educators and schools, industry and community partners, and government as key players who are recommended to interact, engage and collaborate to successfully create a sustained pipeline of STEM talent. Business leaders, university business programs, and business faculty should stay abreast of the factors affecting the supply and demand of STEM workers, and this paper adds value by reporting on CEO perspectives on this important problem

Herbivore regulation of plant abundance in aquatic ecosystems.

Herbivory is a fundamental process that controls primary producer abundance and regulates energy and nutrient flows to higher trophic levels. Despite the recent proliferation of small-scale studies on herbivore effects on aquatic plants, there remains limited understanding of the factors that control consumer regulation of vascular plants in aquatic ecosystems. Our current knowledge of the regulation of primary producers has hindered efforts to understand the structure and functioning of aquatic ecosystems, and to manage such ecosystems effectively. We conducted a global meta-analysis of the outcomes of plant-herbivore interactions using a data set comprised of 326 values from 163 studies, in order to test two mechanistic hypotheses: first, that greater negative changes in plant abundance would be associated with higher herbivore biomass densities; second, that the magnitude of changes in plant abundance would vary with herbivore taxonomic identity. We found evidence that plant abundance declined with increased herbivore density, with plants eliminated at high densities. Significant between-taxa differences in impact were detected, with insects associated with smaller reductions in plant abundance than all other taxa. Similarly, birds caused smaller reductions in plant abundance than echinoderms, fish, or molluscs. Furthermore, larger reductions in plant abundance were detected for fish relative to crustaceans. We found a positive relationship between herbivore species richness and change in plant abundance, with the strongest reductions in plant abundance reported for low herbivore species richness, suggesting that greater herbivore diversity may protect against large reductions in plant abundance. Finally, we found that herbivore-plant nativeness was a key factor affecting the magnitude of herbivore impacts on plant abundance across a wide range of species assemblages. Assemblages comprised of invasive herbivores and native plant assemblages were associated with greater reductions in plant abundance compared with invasive herbivores and invasive plants, native herbivores and invasive plants, native herbivores and mixed-nativeness plants, and native herbivores and native plants. By contrast, assemblages comprised of native herbivores and invasive plants were associated with lower reductions in plant abundance compared with both mixed-nativeness herbivores and native plants, and native herbivores and native plants. However, the effects of herbivore-plant nativeness on changes in plant abundance were reduced at high herbivore densities. Our mean reductions in aquatic plant abundance are greater than those reported in the literature for terrestrial plants, but lower than aquatic algae. Our findings highlight the need for a substantial shift in how biologists incorporate plant-herbivore interactions into theories of aquatic ecosystem structure and functioning. Currently, the failure to incorporate top-down effects continues to hinder our capacity to understand and manage the ecological dynamics of habitats that contain aquatic plants

What CEOs Have to Say: Insights on the STEM Workforce

Establishing and maintaining the supply of skilled STEM workers are issues that many businesses are currently facing. CEOs can provide unique perspectives on the roles of parents, educators and schools, industry and community partners, and government on this issue. To this end, a Qualtrics panel was used to survey 45 CEOs located in the state of Georgia in the southeastern United States. CEOs responded to open-ended questions that were later analyzed using topic modeling techniques to uncover the themes and the factors that have the potential to increase the number of STEM-capable graduates and, ultimately, a sustained STEM workforce. The results of this study indicate that CEOs perceive parents, educators and schools, industry and community partners, and government as key players who are recommended to interact, engage and collaborate to successfully create a sustained pipeline of STEM talent. Business leaders, university business programs, and business faculty should stay abreast of the factors affecting the supply and demand of STEM workers, and this paper adds value by reporting on CEO perspectives on this important problem

Validation of reverse phase protein array for practical screening of potential biomarkers in serum and plasma: Accurate detection of CA19-9 levels in pancreatic cancer

The current study analyzed reverse phase protein arrays (RPPA) as a means to experimentally validate biomarkers in blood samples. One microliter samples of sera ( n  14= 1471), and plasma ( n  14= 1478) were serially diluted and printed on NC-coated slides. CA19-9 levels from RPPA results were compared with identical patient samples as measured by ELISA. There was a strong correlation between RPPA and ELISA ( r  14= 140.87) as determined by scatter plots. Sample reproducibility of CA19-9 levels was excellent (interslide correlation r  14= 140.88; intraslide correlation r  14= 140.83). The ability of RPPA to accurately distinguish CA19-9 levels between cancer and noncancer samples were determined using receiver operating characteristic curves and compared with ELISA. The AUC for RPPA and ELISA was comparable (0.87 and 0.86, respectively). When the mean CA19-9 levels of normal samples was used as a cutoff for RPPA and compared with the standard clinical ELISA cutoff, comparable specificities (71% for both) were observed. Notably, RPPA samples normalized to albumin showed increased sensitivity compared to ELISA (90% vs . 75%). As RPPA is a high-throughput method that shows results comparable to that of ELISA, we propose that RPPA is a viable technique for rapid experimental screening and validation of candidate biomarkers in blood samples.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/60898/1/3051_ftp.pd

Charge Transport Phenomena in Peptide Molecular Junctions

Inelastic electron tunneling spectroscopy (IETS) is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nanoelectronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices

Analysis of the residual safety level in R/C slabs with severe joist corrosion

An analysis until the failure on a series of one-way slabs with severe corrosion at the lower reinforcement of the R/C joists is presented. Different positions in the slab and number of damaged joists have been studied, obtaining the residual safety assessment in cases of slabs damaged by flexural failure mechanisms. Since the boundary conditions have proved decisive for obtaining the behavior, the damaged slab has been evaluated as part of the entire building, as precisely as possible, taking into account the different phases of the construction process and deterioration in time, and the complex behavior of concrete, steel and masonry. The results of the proposed methodology are consistent with the pathology of the observed cases. As a result of this study the authors propose practical recommendations to help in making decisions about the magnitude of the intervention, always necessary in this type of pathology.Vercher Sanchis, JM.; Gil Benso, E.; Mas Tomas, MDLA.; Cubel Arjona, FJ. (2014). Analysis of the residual safety level in R/C slabs with severe joist corrosion. Journal of Performance of Constructed Facilities. 1-14. doi:10.1061/(ASCE)CF.1943-5509.0000608S11