Physiological rules for the heart, lungs and other pressure-based organs.

Background: The adherence of the heart to physical laws, such as Laplace's Law, may act as a measure of the organ's relative efficiency. Allometric relationships were investigated to assess the heart's efficiency concerning end-diastolic and end-systolic volumes, cardiac pressurization energy, cardiac output and mass.

Methods: Data to generate allometric relationships was obtained using a literature search, identifying heart and lung data across different mammalian and bird species.

Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures.

The human rib cage resembles a masonry dome in shape. Masonry domes have a particular construction that mimics stress distribution. Rib cortical thickness and bone density were analyzed to determine whether the morphology of the rib cage is sufficiently similar to a shell dome for internal rib structure to be predicted mathematically.

External rib structure can be predicted using mathematical models: An anatomical study with application to understanding fractures and intercostal muscle function.

As ribs adapt to stress like all bones, and the chest behaves as a pressure vessel, the effect of stress on the ribs can be determined by measuring rib height and thickness. Rib height and thickness (depth) were measured using CT scans of seven rib cages from anonymized cadavers. A Finite Element Analysis (FEA) model of a rib cage was constructed using a validated approach and used to calculate intramuscular forces as the vectors of both circumferential and axial chest wall forces at right angles to the ribs.

Mechanism of sternotomy dehiscence.

Objectives: Biomechanical modelling of the forces acting on a median sternotomy can explain the mechanism of sternotomy dehiscence, leading to improved closure techniques.

Methods: Chest wall forces on 40 kPa coughing were measured using a novel finite element analysis (FEA) ellipsoid chest model, based on average measurements of eight adult male thoracic computerized tomography (CT) scans, with Pearson's correlation coefficient used to assess the anatomical accuracy. Another FEA model was constructed representing the barrel chest of chronic obstructive pulmonary disease (COPD) patients.

Is there a biomechanical cause for spontaneous pneumothorax?

Objectives: Primary spontaneous pneumothorax has long been explained as being without apparent cause. This paper deals with the effect of chest wall shape and explains how this may lead to the pathogenesis of primary spontaneous pneumothorax.

Methods: Rib cage measurements were taken from chest radiographs in 12 male pneumothorax patients and 12 age-matched controls.

Placement of trans-sternal wires according to an ellipsoid pressure vessel model of sternal forces.

Dehiscence of median sternotomy wounds remains a clinical problem. Wall forces in thin-walled pressure vessels can be calculated by membrane stress theory. An ellipsoid pressure vessel model of sternal forces is presented together with its application for optimal wire placement in the sternum.

An extract from Ricinus communis L. leaves possesses cytotoxic properties and induces apoptosis in SK-MEL-28 human melanoma cells.

Plants are an important source of several clinically useful anti-cancer agents. A volatile extract was obtained from Ricinus communis L. (Euphorbiaceae) leaves by standard hydrodistillation and subsequent extraction of the cohobated water in chloroform.

4.3 Towards a global superstore of quality-assured modularized learning programmes.

Our section's assignment entails exploration of the current challenges to develop criteria for quality assurance of dental e-learning material. Our work has involved comparison of current methods of assessment, the identification of best practice and the formulation of guidelines and criteria for producers and assessors. We anticipate the need for a standing international body responsible for the revision and refinement of guidelines and criteria and that might award a 'Seal of Approval'.