Flux Balance Analysis of Mammalian Cell Systems.

Flux balance analysis (FBA) is a computational methodology to model and analyze the metabolic behavior of cells. In this chapter, we break down the key steps for formulating an FBA model and other FBA-derived methodologies in the context of mammalian cell biology, including strain design, developing cell line-specific models, and conducting flux sampling. We provide annotated COBRApy code for each step to show how it would work in practice.

Genome-scale models as a vehicle for knowledge transfer from microbial to mammalian cell systems.

With the plethora of omics data becoming available for mammalian cell and, increasingly, human cell systems, Genome-scale metabolic models (GEMs) have emerged as a useful tool for their organisation and analysis. The systems biology community has developed an array of tools for the solution, interrogation and customisation of GEMs as well as algorithms that enable the design of cells with desired phenotypes based on the multi-omics information contained in these models. However, these tools have largely found application in microbial cells systems, which benefit from smaller model size and ease of experimentation.

How reliable are Chinese hamster ovary (CHO) cell genome-scale metabolic models?

Genome-scale metabolic models (GEMs) possess the power to revolutionize bioprocess and cell line engineering workflows thanks to their ability to predict and understand whole-cell metabolism in silico. Despite this potential, it is currently unclear how accurately GEMs can capture both intracellular metabolic states and extracellular phenotypes. Here, we investigate this knowledge gap to determine the reliability of current Chinese hamster ovary (CHO) cell metabolic models.

Controlling Liquid Crystal Configuration and Phase Using Multiple Molecular Triggers.

Liquid crystals are able to transform a local molecular interaction into a macroscopic change of state, making them a valuable "smart" material. Here, we investigate a novel polymeric amphiphile as a candidate for molecular triggering of liquid crystal droplets in aqueous background. Using microscopy equipped with crossed polarizers and optical tweezers, we find that the monomeric amphiphile is able to trigger both a fast phase change and then a subsequent transition from nematic to isotropic.

Direct Observation of Liquid Crystal Droplet Configurational Transitions using Optical Tweezers.

Liquid crystals (LCs) are easily influenced by external interactions, particularly at interfaces. When rod-like LC molecules are confined to spherical droplets, they experience a competition between interfacial tension and elastic deformations. The configuration of LCs inside a droplet can be controlled using surfactants that influence the interfacial orientation of the LC molecules in the oil-phase of an oil in water emulsion.

Medical device innovation and the value analysis process.

Heidi A. Krantz, RN, BSN is the Director of Value Analysis at Johns Hopkins Bayview Medical Center in the Johns Hopkins Health System. Barbara Strain, MA, CVAHP is the Director of Value Management at the University of Virginia Health System.

An investigation of the impact of the Force Sensing Array pressure mapping system on the clinical judgement of occupational therapists.

Objectives: To examine the impact of pressure mapping technology on the clinical decisions of occupational therapists and to examine the role of the Braden Scale in assisting with the selection of pressure-reducing cushions.

Design: Case studies.

Setting: Community.

Putting laboratory education and experience to work.

Whether you are expanding your job role, mentoring your staff, or addressing students at a middle school career fair, this peer review of skills and job titles will reinforce that laboratory education and experience are valuable in the workforce of today and tomorrow.

Elevated CO(2) studies: past, present and future.

Increasing concentrations of atmospheric CO(2) are predicted to impact both current and future ecosystems. Elevated CO(2) is also predicted to affect biological processes at many levels of organization. In this overview, we summarize the responses of plants to elevated CO(2) including primary physiological and molecular responses, growth and reproductive responses, effects on plant-plant competition and interactions with other organisms, evolutionary responses, and effects at the ecosystem level.

Below-ground carbon input to soil is controlled by nutrient availability and fine root dynamics in loblolly pine.

•  Availability of growth limiting resources may alter root dynamics in forest ecosystems, possibly affecting the land-atmosphere exchange of carbon. This was evaluated for a commercially important southern timber species by installing a factorial experiment of fertilization and irrigation treatments in an 8-yr-old loblolly pine (Pinus taeda) plantation. •  After 3 yr of growth, production and turnover of fine, coarse and mycorrhizal root length was observed using minirhizotrons, and compared with stem growth and foliage development.

A randomized crossover study of silver-coated urinary catheters in hospitalized patients.

Background: Urinary tract infections (UTIs) account for 30% to 40% of nosocomial infections resulting in morbidity, mortality, and increased length of hospital stay.

Objective: To assess the efficacy of a silver-alloy, hydrogel-coated latex urinary catheter for the prevention of nosocomial catheter-associated UTIs.

Methods: A 12-month randomized crossover trial compared rates of nosocomial catheter-associated UTI in patients with silver-coated and uncoated catheters.

Glove leakage rates as a function of latex content and brand: caveat emptor.

Hypothesis: That water leakage rates and protection against blood-borne pathogens should not vary as a function of latex content among Food and Drug Administration-approved gloves, allowing avoidance of unnecessary latex exposure.

Design And Methods: Eighteen different glove types were purchased and tested using the American Society for Testing Methods Standard Test for Detecting Holes in medical gloves, which involves mounting the glove on a plastic tube, pouring a liter of tap water into the glove, and visually inspecting the glove initially and after 2 minutes. Half of the gloves were tested straight from the package and half after a standardized manipulation.

Is atmospheric CO a selective agent on model C annuals?

Atmospheric CO partial pressure (pCO) was as low as 18 Pa during the Pleistocene and is projected to increase from 36 to 70 Pa CO before the end of the 21st century. High pCO often increases the growth and reproduction of C annuals, whereas low pCO decreases growth and may reduce or prevent reproduction. Previous predictions regarding the effects of high and low pCO on C plants have rarely considered the effects of evolution.

Competing in the new health care paradigm: a novel personnel compensation model, Part I.

Operational issues in health care ultimately lead to discussions concerning personnel. Adequate staffing, "rightsizing," compensation, scheduling, morale, supervision, and organizational structure were subjects of the questions the Clinical Pathology Laboratories at the University of Virginia Medical Center asked in 1994. The answers were found in the design of a new skill-based personnel organizational model and compensation plan.

The effect of elevated CO and N availability on tissue concentrations and whole plant pools of carbon-based secondary compounds in loblolly pine (Pinus taeda).

We examined the extent to which carbon investment into secondary compounds in loblolly pine (Pinus taeda L.) is changed by the interactive effect of elevated CO and N availability and whether differences among treatments are the result of size-dependent changes. Seedlings were grown for 138 days at two CO partial pressures (35 and 70 Pa CO) and four N solution concentrations (0.

Diagnosis of vascular catheter-related bloodstream infection: a meta-analysis.

Catheter-related bloodstream infections increased in incidence during the past decade, causing significant morbidity, mortality, and excess hospital costs. Absence of inflammation at the catheter site in most cases makes clinical diagnosis uncertain. The relative accuracy and cost-effectiveness of different microbiologic tests for confirming that bloodstream infection is catheter related have remained unclear.

Contrasting patterns of photosynthetic acclimation and photoinhibition in two evergreen herbs from a winter deciduous forest.

The relationship between the microclimate within an Oak-Hickory forest and photosynthetic characters of two resident evergreen herbs with contrasting leaf phenologies was investigated on a monthly basis for 1 full year. Heuchera americana has leaf flushes in the spring and fall, with average leaf life spans of 6-7 months. Hexastylis arifolia produces a single cohort of leaves each spring with a leaf life span of 12-13 months.

Growth and carbon accumulation in root systems of Pinus taeda and Pinus ponderosa seedlings as affected by varying CO(2), temperature and nitrogen.

It has been hypothesized that increasing atmospheric CO(2) concentration enhances accumulation of carbon in fine roots, thereby altering soil carbon dynamics and nutrient cycling. To evaluate possible changes to belowground pools of carbon and nitrogen in response to elevated CO(2), an early and a late successional species of pine (Pinus taeda L. and Pinus ponderosa Dougl.

Growth and photosynthesis of loblolly pine (Pinus taeda) after exposure to elevated CO(2) for 19 months in the field.

To detect seasonal and long-term differences in growth and photosynthesis of loblolly pine (Pinus taeda L.) exposed to elevated CO(2) under ambient conditions of precipitation, light, temperature and nutrient availability, seedlings were planted in soil representative of an early, abandoned agricultural field and maintained for 19 months in the field either in open-top chambers providing one of three atmospheric CO(2) partial pressures (ambient, ambient +15 Pa, and ambient +30 Pa) or in unchambered control plots. An early and positive response to elevated CO(2) substantially increased total plant biomass.

Direct and indirect effects of elevated CO(2) on whole-shoot respiration in ponderosa pine seedlings.

We determined the short-term direct and long-term indirect effects of CO(2) on apparent dark respiration (CO(2) efflux in the dark) in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) seedlings grown in 35 or 70 Pa CO(2) partial pressure for 163 days in naturally lit, controlled-environment chambers.

Effects of low and elevated CO on C and C annuals : II. Photosynthesis and leaf biochemistry.

Abutilon theophrasti (C) and Amaranthus retroflexus (C), were grown from seed at four partial pressures of CO: 15 Pa (below Pleistocene minimum), 27 Pa (pre-industrial), 35 Pa (current), and 70 Pa (future) in the Duke Phytotron under high light, high nutrient, and wellwatered conditions to evaluate their photosynthetic response to historic and future levels of CO. Net photosynthesis at growth CO partial pressures increased with increasing CO for C plants, but not C plants. Net photosynthesis of Abutilon at 15 Pa CO was 70% less than that of plants grown at 35 Pa CO, due to greater stomatal and biochemical limitations at 15 Pa CO.

Effects of low and elevated CO on C and C annuals : I. Growth and biomass allocation.

In order study C and C plant growth in atmospheric CO levels ranging from past through predicted future levels, Abutilon theophrasti (C) and Amaranthus retroflexus (C) were grown from seed in growth chambers controlled at CO partial pressures of 15 Pa (below Pleistocene minimum), 27 Pa (pre-industrial), 35 Pa (current) and 70 Pa (predicted future). After 35 days of growth, CO had no effect on the relative growth rate, total biomass or partitioning of biomass in the C species. However, the C species had greater biomass accumulation with increasing CO partial pressure.