Elastomeric microfluidic diode and rectifier work with Newtonian fluids

We report on two microfluidic elastomeric autoregulatory devices—a diode and a rectifier. They exhibit physically interesting and complex nonlinear behaviors (saturation, bias-dependent resistance, and rectification) with a Newtonian fluid. Due to their autoregulatory properties, they operate without active external control. As a result, they enable increased microfluidic device density and overall system miniaturization. The demonstrated diode and rectifier would also be useful components in future microfluidic logic circuitry

Variational calculations on the hydrogen molecular ion

We present high-precision non-relativistic variational calculations of bound vibrational-rotational state energies for the $H_2^+$ and $D_2^+$ molecular ions in each of the lowest electronic states of $\Sigma_g$, $\Sigma_u$, and $\Pi_u$ symmetry. The calculations are carried out including coupling between $\Sigma$ and $\Pi$ states but without using the Born-Oppenheimer or any adiabatic approximation. Convergence studies are presented which indicate that the resulting energies for low-lying levels are accurate to about $10^{-13}$. Our procedure accounts naturally for the lambda-doubling of the $\Pi_u$ state.Comment: 23 pp., RevTeX, epsf.sty, 5 figs. Enhanced data in Table II, dropped 3 figs. from previous versio

Measurement and models accounting for cell death capture hidden variation in compound response.

Cancer cell sensitivity or resistance is almost universally quantified through a direct or surrogate measure of cell number. However, compound responses can occur through many distinct phenotypic outcomes, including changes in cell growth, apoptosis, and non-apoptotic cell death. These outcomes have divergent effects on the tumor microenvironment, immune response, and resistance mechanisms. Here, we show that quantifying cell viability alone is insufficient to distinguish between these compound responses. Using an alternative assay and drug-response analysis amenable to high-throughput measurement, we find that compounds with identical viability outcomes can have very different effects on cell growth and death. Moreover, additive compound pairs with distinct growth/death effects can appear synergistic when only assessed by viability. Overall, these results demonstrate an approach to incorporating measurements of cell death when characterizing a pharmacologic response

Explorando os resultados de inscrição simultânea com base em padrões e Advanced Placement no Arkansas

Accelerated programs (concurrent enrollment and Advanced Placement) are expanding across the US, yet there is little evidence on the relationships between participation in different accelerated programs, standards-based concurrent enrollment programs (e.g., accredited programs), and educational outcomes. This study used data from a cohort of Arkansas high school graduates and school-level fixed effects to assess how different accelerated programs predict students’ likelihood of enrolling in and being retained in an Arkansas college. We found that participation in concurrent enrollment and Advanced Placement predicts college access and college retention. However, we found no differences in college access and retention based on whether students participated in a NACEP-accredited concurrent enrollment program or not. The results suggest the need to expand access to both concurrent enrollment and Advanced Placement and the need for more research on standards-based concurrent enrollment programs such as those that are NACEP-accredited. Los programas acelerados (inscripción simultánea y Advanced Placement) se están expandiendo en los EE. UU., Aunque hay poca evidencia sobre las relaciones entre la participación en diferentes programas acelerados, programas de inscripción concurrente basados en estándares (por ejemplo, programas acreditados) y resultados educativos. Este estudio utilizó datos de una cohorte de graduados de la escuela secundaria de Arkansas y efectos fijos a nivel escolar para evaluar cómo los diferentes programas acelerados predicen la probabilidad de los estudiantes de inscribirse y ser retenidos en una universidad de Arkansas. Descubrimos que la participación en la inscripción simultánea y la Advanced Placement predice el acceso a la universidad y la retención universitaria. Sin embargo, no encontramos diferencias en el acceso a la universidad y la retención en función de si los estudiantes participaron en un programa de inscripción simultánea acreditado por NACEP o no. Los resultados sugieren la necesidad de ampliar el acceso tanto a la inscripción concurrente como a la Advanced Placement y la necesidad de más investigación sobre programas de inscripción concurrente basados en estándares, como los que están acreditados por NACEP.Programas acelerados (inscrição simultânea e Advanced Placement) estão se expandindo nos EUA. Embora haja poucas evidências sobre as relações entre a participação em diferentes programas acelerados, programas de inscrição simultâneos com base em padrões (por exemplo, programas credenciados) e resultados educacionais. Este estudo usou dados de uma coorte de graduados do ensino médio do Arkansas e efeitos fixos em toda a escola para avaliar como diferentes programas acelerados prevêem a probabilidade de os alunos se matricularem e serem mantidos em uma universidade de Arkansas. Descobrimos que a participação em matrículas simultâneas e Advanced Placement prevê o acesso à universidade e a retenção universitária. No entanto, não encontramos diferenças no acesso à universidade e à retenção, dependendo se os alunos participaram ou não de um programa de inscrição concorrente credenciado pela NACEP. Os resultados sugerem a necessidade de expandir o acesso tanto a inscrições simultâneas quanto a Advanced Placement e a necessidade de mais pesquisas sobre programas de inscrição simultânea com base em padrões, como aqueles credenciados pelo NACEP

Large U(1) charges from flux breaking in 4D F-theory models

We study the massless charged spectrum of U(1) gauge fields in F-theory that arise from flux breaking of a nonabelian group. The U(1) charges that arise in this way can be very large. In particular, using vertical flux breaking, we construct an explicit 4D F-theory model with a U(1) decoupled from other gauge sectors, in which the massless/light fields have charges as large as 657. This result greatly exceeds prior results in the literature. We argue heuristically that this result may provide an upper bound on charges for light fields under decoupled U(1) factors in the F-theory landscape. We also show that the charges can be even larger when the U(1) is coupled to other gauge groups.Comment: 29 pages, 1 figur

Towards Smarter Cities: Linking Human Mobility and Energy Use Fluctuations across Building Types

Urban areas consume up to 80 percent of the world\u27s total energy production and are growing in size and complexity. At present, urban building energy consumption is largely considered solely in terms of individual building types, neglecting the effects of residents’ location-based activities that influence patterns in energy supply and demand. Here, we examine the spatial fluctuations of these effects. A spatial regression analysis of 3,613,360 positional records containing human mobility and energy consumption data across 983 areas in Greater London and 801 areas in the City of Chicago in residential and commercial buildings over the course of one month revealed spatial dependencies for both residential and commercial buildings’ energy consumption on human mobility. This dependency represents a strong connection with residential buildings’ energy consumption, with a spatial spillover effect. Future energy efficiency strategies should thus reflect the spatial dependencies, creating new ways for residential buildings to play a major role in energy related strategies

A microfluidic processor for gene expression profiling of single human embryonic stem cells

The gene expression of human embryonic stem cells (hESC) is a critical aspect for understanding the normal and pathological development of human cells and tissues. Current bulk gene expression assays rely on RNA extracted from cell and tissue samples with various degree of cellular heterogeneity. These cell population averaging data are difficult to interpret, especially for the purpose of understanding the regulatory relationship of genes in the earliest phases of development and differentiation of individual cells. Here, we report a microfluidic approach that can extract total mRNA from individual single-cells and synthesize cDNA on the same device with high mRNA-to-cDNA efficiency. This feature makes large-scale single-cell gene expression profiling possible. Using this microfluidic device, we measured the absolute numbers of mRNA molecules of three genes (B2M, Nodal and Fzd4) in a single hESC. Our results indicate that gene expression data measured from cDNA of a cell population is not a good representation of the expression levels in individual single cells. Within the G0/G1 phase pluripotent hESC population, some individual cells did not express all of the 3 interrogated genes in detectable levels. Consequently, the relative expression levels, which are broadly used in gene expression studies, are very different between measurements from population cDNA and single-cell cDNA. The results underscore the importance of discrete single-cell analysis, and the advantages of a microfluidic approach in stem cell gene expression studies