Six personas to adopt when framing theoretical research questions in biology.

Theory is a critical component of the biological research process, and complements observational and experimental approaches. However, most biologists receive little training on how to frame a theoretical question and, thus, how to evaluate when theory has successfully answered the research question. Here, we develop a guide with six verbal framings for theoretical models in biology.

EVALUATION OF IMMUNE FUNCTION IN TWO POPULATIONS OF GREEN SEA TURTLES (CHELONIA MYDAS) IN A DEGRADED VERSUS A NONDEGRADED HABITAT.

There is a strong correlation between degraded marine habitats and the prevalence of diseases such as green turtle fibropapillomatosis (GTFP) in coastal populations. In GTFP, small to large tumors grow on the turtle's soft tissues and shell, while internal nodules may also occur. The disease primarily affects juvenile green sea turtles (Chelonia mydas) that reside in nearshore waters.

Allonymous science: the politics of placing and shifting credit in public-private nutrition research.

Ideally, guidelines reflect an accepted position with respect to matters of concern, ranging from clinical practices to researcher behaviour. Upon close reading, authorship guidelines reserve authorship attribution to individuals fully or almost fully embedded in particular studies, including design or execution as well as significant involvement in the writing process. These requirements prescribe an organisation of scientific work in which this embedding is specifically enabled.

Standardized Definitions of Bleeding After Transbronchial Lung Biopsy: A Delphi Consensus Statement From the Nashville Working Group.

Background: Transbronchial lung biopsies are commonly performed for a variety of indications. Although generally well tolerated, complications such as bleeding do occur. Description of bleeding severity is crucial both clinically and in research trials; to date, there is no validated scale that is widely accepted for this purpose.

Production Standard and Stability of Compounded Del Nido Cardioplegia Solution.

The del Nido cardioplegia solution (dNCS) was originally developed for pediatric cardiac surgery, being now also used for adult patients. Hospital pharmacies frequently resort to internal dNCS production which has led to an increase in the need for validated parameters for compounding and storage. This report defines in-house production standards, as well as the stability of dNCS under optimal storage conditions.

Sterile product compounding using an i.v. compounding workflow management system at a pediatric hospital.

Purpose: Patient safety enhancements achieved through the use of an automated i.v. compounding workflow management system are reported.

Redistributional consequences of early childhood intervention.

Recently, early investment in the human capital of children from socially disadvantaged environments has attracted a great deal of attention. Programs of such early intervention, aimed at children's health and well-being, are spreading considerably in the US and are currently being tested in several European countries. In a discrete version of the Mirrlees model with a parents' and a children's generation, we model the intra-generational and the inter-generational redistributional consequences of such intervention programs.

An official American thoracic society statement: position statement on ATS activities for the promotion of respiratory and sleep/wake health and the care of the critically ill in the United States.

Background: The 1997 American Thoracic Society (ATS) statement "A Framework for Health Care Policy in the United States" outlined core principles for the Society's activities in the public health arena. In the succeeding 10 years, profound changes have taken place in the United States health care environment. In addition, the 2005 publication of the Society's Vision highlighted some differences between the original Statement and our current priorities.

Effect of anoxia on the electroretinogram of three anoxia-tolerant vertebrates.

To survive anoxia, neural ATP levels have to be defended. Reducing electrical activity, which accounts for 50% or more of neural energy consumption, should be beneficial for anoxic survival. The retina is a hypoxia sensitive part of the central nervous system.

Regulation of extracellular glutamate levels in the long-term anoxic turtle striatum: coordinated activity of glutamate transporters, adenosine, K (ATP) (+) channels and GABA.

Early in anoxia the mammalian brain experiences an uncontrolled release of glutamate, which combined with the failure of glutamate reuptake mechanisms, leads to massive neurotoxic increases in extracellular glutamate. By contrast, the anoxia tolerant turtle (Trachemys scripta) shows no increase in extracellular glutamate levels over many hours of anoxia. During the first hours of anoxia extracellular glutamate levels are maintained by a reduction in glutamate release (mainly due to the inhibition of neuronal vesicular glutamate release), combined with continued uptake by still active glutamate transporters.

Predictive sensor based x-ray calibration using a physical model.

Many computer assisted surgery systems are based on intraoperative x-ray images. To achieve reliable and accurate results these images have to be calibrated concerning geometric distortions, which can be distinguished between constant distortions and distortions caused by magnetic fields. Instead of using an intraoperative calibration phantom that has to be visible within each image resulting in overlaying markers, the presented approach directly takes advantage of the physical background of the distortions.

Ontogeny of energetics in leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) sea turtle hatchlings.

Changes in activity related oxygen consumption were measured in leatherback and olive ridley sea turtle hatchlings over their first month after emergence from the nest. Leatherbacks emerged with 75-90 KJ of energy in the residual yolk for growth and activity whereas olive ridleys emerged with 45 KJ. In leatherbacks (n=8), resting mass-specific oxygen consumption rates decreased by 53% over the first post-hatching month (0.

Gene transcription of neuroglobin is upregulated by hypoxia and anoxia in the brain of the anoxia-tolerant turtle Trachemys scripta.

Neuroglobin is a heme protein expressed in the vertebrate brain in mammals, fishes, and birds. The physiological role of neuroglobin is not completely understood but possibilities include serving as an intracellular oxygen-carrier or oxygen-sensor, as a terminal oxidase to regenerate NAD(+) under anaerobic conditions, or involvement in NO or ROS metabolism. As the vertebrate nervous system is particularly sensitive to hypoxia, an intracellular protein that helps sustain cellular respiration would aid hypoxic survival.

Adenosine and ATP-sensitive potassium channels modulate dopamine release in the anoxic turtle (Trachemys scripta) striatum.

Excessive dopamine (DA) is known to cause hypoxic/ischemic damage to mammalian brain. The freshwater turtle Trachemys scripta, however, maintains basal striatal DA levels in anoxia. We investigated DA balance during early anoxia when energy status in the turtle brain is compromised.

Negotiating brain anoxia survival in the turtle.

The turtle brain's extraordinary ability to tolerate anoxia is based on constitutive and expressed factors. Constitutive factors that predispose for anoxia tolerance include enhanced levels of glycogen stores, increased densities of protective receptors, elevated antioxidant capacities and elevated heat shock protein. However, to survive an anoxic insult, three distinct phases must be negotiated successfully.

Vertebrate brains at the pilot light.

While the brains of most vertebrates are unable to tolerate more than a few minutes of anoxia, some freshwater turtles (Trachemys and Chrysemys), crucian carp (Carassius carassius) and frogs (Rana pipens and Rana temporaria) can survive anoxia for hours to months. Obviously, anoxia tolerance has evolved separately several times and this is also reflected in the divergent strategies these animals utilize to survive without oxygen. The turtles and crucian carp defend their brain ATP levels and avoid a loss of ion homeostasis by reducing ATP use.

The upregulation of cognate and inducible heat shock proteins in the anoxic turtle brain.

Because heat shock proteins (HSPs) have an important protective function against ischemia/anoxia in mammalian brain, the authors investigated the expression of Hsp72 and Hsc73 in the anoxia-surviving turtle brain. Unlike the mammalian brain, high levels of Hsp72 were found in the normoxic turtle brain. Hsp72 levels were significantly increased by 4 hours of anoxia, remained constant until 8 hours, and then decreased to baseline at 12 hours.

Anoxia tolerant brains.

While medical science has struggled to find ways to counteract anoxic brain damage with limited success, evolution has repeatedly solved this problem. The best-studied examples of anoxia-tolerant vertebrates are the crucian carp and some North American Freshwater turtles. These can survive anoxia for days to months, depending of temperature.

Gene transcription of brain voltage-gated potassium channels is reversibly regulated by oxygen supply.

Voltage-dependent potassium channels (Kv channels) are important determinants of brain electrical activity. Hypoxia may be an important modifier, because several voltage-gated K+ channels are reversibly blocked by acute hypoxia and are thought to act as oxygen sensors. Here we show, using the anoxia-tolerant turtle brain (Trachemys scripta) as a model, that brain Kv1 channel transcription is reversibly regulated by oxygen supply.

Slow death in the leopard frog Rana pipiens: neurotransmitters and anoxia tolerance.

While frogs such as Rana temporaria are known to withstand 4-5 h anoxia at room temperature, little is known about the neurological adaptations that permit this. Previous research has shown that changes in neuroactive compounds such as glutamate and dopamine in anoxia-sensitive (mammalian) brains follow a strikingly different pattern than is observed in truly anoxia-tolerant vertebrates such as the freshwater turtle. The present study measured changes in the levels of whole brain and extracellular amino acids, and extracellular dopamine, in the normoxic and 3-4 h anoxic frog Rana pipiens, in order to determine whether their neurotransmitter responses resemble the anoxia-vulnerable or anoxia-tolerant response.

Is turtle longevity linked to enhanced mechanisms for surviving brain anoxia and reoxygenation?

We suggest that the processes that protect the turtle brain against anoxia and subsequent reoxygenation might also contribute to turtle longevity since many of them are linked to age related neurodegeneration. In the turtle the mechanisms for conserving ion channel function are particularly robust. The anoxic turtle brain avoids excitatory neurotransmitter toxicity by maintaining a balance between dopamine and glutamate-release and still active uptake mechanisms.

Photoreduction of bicarbonate catalyzed by supported cadmium sulfide.

Cadmium sulfide supported on silica (CdS-chi/SiO2, chi = 4, 11, 17, 25%) and zinc sulfide (CdS-chi/ZnS, chi = 5, 10, 20, 30%) was prepared by impregnation with cadmium sulfate and subsequent addition of sodium sulfide. The specific surface areas of the silica and zinc sulfide supported powders are in the range o f 188-280 and 95-104 m2 g(-1), respectively. After sonication of an aqueous suspension of CdS-17/SiO2 the particle size distribution exhibited two maxima at 22 and 57 microm.

Sensing and responding to hypoxia, molecular and physiological mechanisms.

In order to adapt to low oxygen it is necessary first to be able to detect hypoxia, then to initiate the appropriate defense mechanisms. There are two basic detectors: molecular sensors that are directly linked to gene regulation and metabolic indicators that are triggered when the cell goes into a state of energy imbalance. The molecular responses to oxygen deprivation are characterized in a variety of cell types and include activation of oxygen sensors, signaling through specific promoter elements and subsequent downstream adaptations.

Mechanisms for maintaining extracellular glutamate levels in the anoxic turtle striatum.

The turtle Trachemys scripta is one of a limited group of vertebrates that can withstand hours to days without oxygen. One facet of anoxic survival is the turtle's ability to maintain basal extracellular glutamate levels, whereas in most vertebrates, anoxia triggers massive excitotoxic glutamate release. We investigated glutamate release and reuptake in the anoxic turtle and the effects of adenosine and ATP-sensitive potassium (K(ATP)) channels on glutamate homeostasis.