Experimental evaluation of apparent tissue surface tension based on the exact solution of the Laplace equation

The notion of apparent tissue surface tension offered a systematic way to interpret certain morphogenetic processes in early development. It also allowed deducing quantitative information on cellular and molecular parameters that is otherwise difficult to obtain. To accurately determine such tensions we combined novel experiments with the exact solution of the Laplace equation for the profile of a liquid drop under the employed experimental conditions and used the exact solution to evaluate data collected on tissues. Our results confirm that tissues composed of adhesive and motile cells indeed can be characterized in terms of well-defined apparent surface tension. Our experimental technique presents a way to measure liquid interfacial tensions under conditions when known methods fail.This work was supported by the National Science Foundation [FIBR-0526854]

Mémento pour la gestion des projets d'assainissement : fascicule 3 : les eaux pluviales

Ce fascicule aborde la gestion des eaux pluviales à deux niveaux : celui de la planification, du fait de l’importance de cette réflexion amont (fiche « enjeux d’urbanisme et d’aménagement »), et celui du projet d'aménagement, public ou privé, de type rénovation urbaine, création de lotissement, de ZAC, de zone industrielle, … Il ne traite pas le projet pluvial "isolé" du projet d'aménagement (création ou réhabilitation de collecteur, dispositif de traitement des eaux pluviales, …). Il insiste sur l’importance de prendre en compte la gestion des eaux pluviales très à l’amont du projet et en associant très tôt l’ensemble des acteurs de l’aménagement

Biofabrication: an overview of the approaches used for printing of living cells

The development of cell printing is vital for establishing biofabrication approaches as clinically relevant tools. Achieving this requires bio-inks which must not only be easily printable, but also allow controllable and reproducible printing of cells. This review outlines the general principles and current progress and compares the advantages and challenges for the most widely used biofabrication techniques for printing cells: extrusion, laser, microvalve, inkjet and tissue fragment printing. It is expected that significant advances in cell printing will result from synergistic combinations of these techniques and lead to optimised resolution, throughput and the overall complexity of printed constructs

THE “PENDULUM LAW” - HOW TO EXPLAIN THE COLUMN SHAPE BASED ON COMMON ANOMALIES? PART II

ABSTRACT In Part I, the author defines an organizational law of the body schema: the “pendulum law”, describing an ideal biomechanical structure of the spine. Thus, he shows how the common variations and anomalies, whether isolated or associated, modify the standard biomechanical scheme. The variations of isolated “curl/roll up” of the sacrum. Anomalies of the lumbosacral joint in the sagittal (LSS) and/or rotational (LSR) plan. Anomalies of stabilization of the capsule of the hip joint and the sacro-diaphyseal angle. Specific anomalies with grade 1 spondylolysis (SL). Segmental anomalies of the vertebral discs in flexion (Rx). Associated anomalies (SL + Rx + ASL= Rx). The interest of studying the impact on the vertical construction of the vertebral column, according to the “ideal” scheme is to establish the physiological limits of this gravitational law, to identify the anomalies, to classify schemes and types, and the biomechanical degenerative consequences