The thermodynamics of metabolism, cardiovascular performance and exercise, in health and diabetes: The objective of clinical markers

Extensive experience in UK National Health Service metabolic syndrome/type 2 diabetes clinics highlights the need for convenient clinical marker(s) which can be readily used to indicate the success or otherwise of alternative therapies. In this paper we study the metabolic context of the healthy and diseased states, which points to the haemodynamics being a possible key in identifying candidate markers. Human metabolism relates to two elemental thermodynamic systems, the individual cell and the human body in its entirety. The fundamental laws of thermodynamics apply to humans, animals, and their individual cells for both healthy and diseased conditions. as they are to classic heat engines. In compliance with the second law enhanced levels of heat are generated under exercise, heat itself being another factor modulating the cardiovascular response to physical exercise. Nutrients and oxygen uptake occurs via the digestive system and lungs, respectively, leading to ATP production by the established metabolic pathways: this is controlled by insulin. These are then delivered to the cells via the haemodynamic system to satisfy local metabolic need. The supply and demand of oxygen are finely regulated, in part, via oxygen-dependent release of ATP from the circulating erythrocytes. Energy supply and demand are regulated to sustain muscle activity resulting in the body’s output of measurable thermodynamic work—i.e. exercise. Recently a dynamic pathway model allowing quantification of ATP release from the erythrocytes and its contribution to oxygen supply regulation has been published. However, metabolic uptake is well known to be greatly affected by disease such as the highly prevalent diabetes type 2 with insulin resistance and beta cell dysfunction having mechanistic roles. In 2010, over 25% of residents above 65 in the USA had diabetes 2. The complexity of the metabolic pathways means that monitoring of patient-specific treatment would be beneficial from a diabetic marker which may be haemodynamic-related and traceable via the local fluid dynamics

Advanced architectural descriptors in foams: novel 3D computational methods

This work presents 3D computational strategies aimed at providing foam de-structuration of the basic components of a cellular material (struts and cell walls) offering the possibility of analysing separately the structural elements that play an important role in the physical properties of thee materials. Two different methodologies have been used depending on the topological similarities existing between the struts and cell walls: 3D erosion-dilation procedure (thick struts) and solid classification algorithm (thin struts). In a second step, analysis of cell walls is performed in order to show the advantages of analysing separately the two foams components. Particularly, cell wall thickness distribution reveals differences that could not be found prior to the de-structuration

Un modelo conceptual sobre el funcionamiento de los ríos mediterráneos sometidos a perturbaciones naturales (riadas y sequías)

The Mediterranean regions are prone to suffer extraordinary flash-floods and prolonged droughts. Between these extreme events, there are small floods and droughts that are more common and more predictable. These smaller floods and droughts, along with the others mentioned before generate an extraordinarily complex temporal hydrological picture whose affects have been partly described by different authors, including those affecting the human population. The information compiled during nearly two decades by the group of Ecology of Continental Waters of the University of Murcia, about the effects of these events on rivers of the Segura River Basin, allows for elaborating a conceptual model about the function of several physical, physico-chemical, and biological parameters in rivers in the southwest, in particular and Mediterranean rivers in general.Las regiones mediterráneas son proclives a sufrir avenidas extraordinarias y sequías prolongadas. Entre estos eventos extremos, se sitúan las crecidas y estiajes más habituales y predecibles que, junto a los anteriores configuran un cuadro hidrológico temporal extraordinariamente complejo cuyos efectos han sido descritos parcialmente por diferentes autores, incluidos aquellos que afectan a la población humana. La información recogida durante casi dos décadas por el Grupo de Ecología de Aguas Continentales de la Universidad de Murcia, sobre los efectos de estos eventos en ríos de la Cuenca del Segura, permite elaborar un modelo conceptual sobre el funcionamiento de distintos parámetros físicos, físico-químicos y biológicos en ríos del sureste, en particular y mediterráneos, en general

Hypoalbuminaemia predicts outcome in adult patients with congenital heart disease

Background In patients with acquired heart failure, hypoalbuminaemia is associated with increased risk of death. The prevalence of hypoproteinaemia and hypoalbuminaemia and their relation to outcome in adult patients with congenital heart disease (ACHD) remains, however, unknown. Methods Data on patients with ACHD who underwent blood testing in our centre within the last 14 years were collected. The relation between laboratory, clinical or demographic parameters at baseline and mortality was assessed using Cox proportional hazards regression analysis. Results A total of 2886 patients with ACHD were included. Mean age was 33.3 years (23.6–44.7) and 50.1% patients were men. Median plasma albumin concentration was 41.0 g/L (38.0–44.0), whereas hypoalbuminaemia (<35 g/L) was present in 13.9% of patients. The prevalence of hypoalbuminaemia was significantly higher in patients with great complexity ACHD (18.2%) compared with patients with moderate (11.3%) or simple ACHD lesions (12.1%, p<0.001). During a median follow-up of 5.7 years (3.3–9.6), 327 (11.3%) patients died. On univariable Cox regression analysis, hypoalbuminaemia was a strong predictor of outcome (HR 3.37, 95% CI 2.67 to 4.25, p<0.0001). On multivariable Cox regression, after adjusting for age, sodium and creatinine concentration, liver dysfunction, functional class and disease complexity, hypoalbuminaemia remained a significant predictor of death. Conclusions Hypoalbuminaemia is common in patients with ACHD and is associated with a threefold increased risk of risk of death. Hypoalbuminaemia, therefore, should be included in risk-stratification algorithms as it may assist management decisions and timing of interventions in the growing ACHD population

Coexistence of Haldane gap excitations and long-range order in R_2BaNiO_5 (RR=rare earth)

$R_2BaNiO_5$ ($R=$ rare earth) quasi-1-D antiferromagnets are structurally equivalent to the well-studied 1-D S=1 Haldane-gap compound Y_2BaNiO_5. Unlike the Y-nickelate though, these materials undergo 3-D magnetic ordering at finite temperatures. Recent inelastic neutron scattering studies of Pr_2BaNiO_5 and (Nd_{x}Y_{1-x})_2BaNiO_5 revealed purely 1-dimensional gap excitations that propagate exclusively on the Ni-chains and are strikingly similar to Haldane gap modes in Y_2BaNiO_5. In the ordered phase these excitations survive and actually coexist with conventional spin waves. Below $T_{N}$ the gap energy increases and scales as the square of the ordered moment on the Ni sites. The results suggest that the Haldane singlet ground state of the Ni-chains is not fully destroyed by N\'{e}el ordering.Comment: Invited paper for the International Conference on Neutron Scattering, Toronto, Canada, August 17-21, 199