Evolution of dispersal in river networks.

Evolution of dispersal is a fascinating topic at the intersection of ecology and evolutionary dynamics that has generated many challenging problems in the analysis of reaction-diffusion equations. Early results indicated that lower random diffusion rates are generally beneficial. However, in riverine environments with downstream drift, high diffusion may be optimal, depending on downstream boundary conditions.

Method for reproducible automated bacterial cell culture and measurement.

Microbial cell culture is one of the most commonly performed protocols for synthetic biology, and laboratories are increasingly using 96-well plates and laboratory automation systems for cell culture. Here, we describe a method for reproducible microbial culture using laboratory automation systems, including automated liquid handling, automated plate sealing and de-sealing, automated incubation and measurement of growing cultures. We discuss the key considerations that, in our experience, are important for reproducibility and present statistical analyses of data from 150 automated microbial growth experiments performed over 27 months using our automated method.

The genotype-phenotype landscape of an allosteric protein.

Allostery is a fundamental biophysical mechanism that underlies cellular sensing, signaling, and metabolism. Yet a quantitative understanding of allosteric genotype-phenotype relationships remains elusive. Here, we report the large-scale measurement of the genotype-phenotype landscape for an allosteric protein: the lac repressor from Escherichia coli, LacI.

Population dynamics in river networks: analysis of steady states.

We study the population dynamics of an aquatic species in a river network. The habitat is viewed as a binary tree-like metric graph with the population density satisfying a reaction-diffusion-advection equation on each edge, along with the appropriate junction and boundary conditions. In the case of a linear reaction term and hostile downstream boundary condition, the question of persistence in such models was studied by Sarhad, Carlson and Anderson.

Loss of the Cochlear Amplifier Prestin Reduces Temporal Processing Efficacy in the Central Auditory System.

Active mechanical amplification of sound occurs in cochlear outer hair cells (OHCs) that change their length with oscillations of their membrane potential. Such length changes are the proposed cellular source of the cochlear amplifier, and prestin is the motor protein responsible for OHC electromotility. Previous findings have shown that mice lacking prestin displayed a loss of OHC electromotility, subsequent loss of distortion-product otoacoustic emissions, and a 40-60 dB increase in hearing thresholds.

Evaluation of phenytoin serum levels following a loading dose in the acute hospital setting.

Purpose: Due to the complex pharmacokinetic profiles of phenytoin (PHT) and fosphenytoin (FOS), achieving sustained, targeted serum PHT levels in the first day of use is challenging.

Methods: A population based approach was used to analyze total serum PHT (tPHT) level within 2-24h of PHT/FOS loading with or without supplementary maintenance or additional loading doses among PHT-naïve patients in the acute hospital setting. Adequate tPHT serum level was defined as ≥20μg/mL.

Competition of Multiple Species in Advective Environments.

We study the effect of changes in flow speed on competition of an arbitrary number of species living in advective environments, such as streams and rivers. We begin with a spatial Lotka-Volterra model which is described by n reaction-diffusion-advection equations with Danckwerts boundary conditions. Using the dominant eigenvalue [Formula: see text] of the diffusion-advection operator subject to boundary conditions, we reduce the model to a system of ordinary differential equations.

Supplemental Antithrombin Is Effective in Achieving Adequate Anticoagulation in Infants and Children With an Inadequate Response to Heparin.

Objective: To demonstrate that supplemental antithrombin (AT) is effective in establishing adequate anticoagulation in infants and children with initially inadequate responses to heparin.

Design: Following institutional review board approval, a retrospective chart review was conducted on pediatric patients receiving AT during cardiac surgery requiring cardiopulmonary bypass.

Setting: A single institutional review in a hospital setting.

Fibrosis biomarkers in workers exposed to MWCNTs.

Multi-walled carbon nanotubes (MWCNT) with their unique physico-chemical properties offer numerous technological advantages and are projected to drive the next generation of manufacturing growth. As MWCNT have already found utility in different industries including construction, engineering, energy production, space exploration and biomedicine, large quantities of MWCNT may reach the environment and inadvertently lead to human exposure. This necessitates the urgent assessment of their potential health effects in humans.

Analysis of spread and persistence for stream insects with winged adult stages.

Species such as stoneflies have complex life history details, with larval stages in the river flow and adult winged stages on or near the river bank. Winged adults often bias their dispersal in the upstream direction, and this bias provides a possible mechanism for population persistence in the face of unidirectional river flow. We use an impulsive reaction-diffusion equation with non-local impulse to describe the population dynamics of a stream-dwelling organism with a winged adult stage, such as stoneflies.

Aggregation and environmental transmission in Chronic Wasting Disease.

Disease transmission depends on the interplay between the infectious agent and the behavior of the host. Some diseases, such as Chronic Wasting Disease, can be transmitted directly between hosts as well as indirectly via the environment. The social behavior of hosts affects both of these pathways, and a successful intervention requires knowledge of the relative influence of the different etiological and behavioral aspects of the disease.

Modeling seasonal behavior changes and disease transmission with application to chronic wasting disease.

Behavior and habitat of wildlife animals change seasonally according to environmental conditions. Mathematical models need to represent this seasonality to be able to make realistic predictions about the future of a population and the effectiveness of human interventions. Managing and modeling disease in wild animal populations requires particular care in that disease transmission dynamics is a critical consideration in the etiology of both human and animal diseases, with different transmission paradigms requiring different disease risk management strategies.

How flow speed alters competitive outcome in advective environments.

Many species live in advective environments, such as rivers or streams. The community composition in such environments is shaped by the interplay between biotic interactions and hydrologic constraints. Lutscher et al.

Ablation of mixed lineage kinase 3 (Mlk3) does not inhibit ototoxicity induced by acoustic trauma or aminoglycoside exposure.

Jun N-terminal kinase (JNK) is activated in cochlear hair cells following acoustic trauma or exposure to aminoglycoside antibiotics. Blockade of JNK activation using mixed lineage kinase (MLK) inhibitors prevents hearing loss and hair cell death following these stresses. Since current pharmacologic inhibitors of MLKs block multiple members of this kinase family, we examined the contribution of the major neuronal family member (MLK3) to stress-induced ototoxicity, usingMlk3(-/-) mice.

Interactions of hearing loss and diabetes mellitus in the middle age CBA/CaJ mouse model of presbycusis.

Recently, we characterized the more severe nature of hearing loss in aged Type 2 diabetic human subjects [Frisina, S.T., Mapes, F.

Hormone replacement therapy diminishes hearing in peri-menopausal mice.

We recently discovered that progestin in hormone replacement therapy (HRT) for post-menopausal women has detrimental effects on the ear and central auditory system [Guimaraes, P., Frisina, S.T.

Auditory efferent feedback system deficits precede age-related hearing loss: contralateral suppression of otoacoustic emissions in mice.

The C57BL/6J mouse has been a useful model of presbycusis, as it displays an accelerated age-related peripheral hearing loss. The medial olivocochlear efferent feedback (MOC) system plays a role in suppressing cochlear outer hair cell (OHC) responses, particularly for background noise. Neurons of the MOC system are located in the superior olivary complex, particularly in the dorsomedial periolivary nucleus (DMPO) and in the ventral nucleus of the trapezoid body (VNTB).