Structural and interaction properties of β-Lactoglobulin as studied by FTIR spectroscopy

Summary New aspects of β-Lactoglobulin (BLG) structure which have not previously been found by FT–IR spectroscopy are presented. The conformational changes of BLG and its heat-induced denaturation have been studied at low concentration and different pHs. First, it was found that the spectra of BLG in solution are concentration-dependent. Below 1%, they reveal one component in the 1620–1635 cm⁻¹ region while above this concentration, two components are present. These changes are related to the modifications of the quaternary structure of BLG, i.e. to the monomeric or dimeric forms. As shown at high temperature (85 °C), this concentration (1%) represents the threshold of protein aggregation. Second, the thermal behaviour of BLG at pH 7.4 and 4.4 is compared. The results suggest that the denaturation process and the intermolecular interactions in aggregates are different and lead to two types of aggregate. These observations are in agreement with the formation of two gel microstructures near neutral pH and near the pI of BLG as observed by Stading & Hermasson (1990). Finally, interactions between BLG and two zwitterionic phospholipids have been investigated. Dipalmitoylphosphatidylcholine (DPPC) is unaffected in the presence of BLG, suggesting that no interaction occurs. In contrast, BLG increases the lipid chain conformational disorder of milk sphinglomyelin (SM) as a consequence of hydrophobic interactions of BLG with SM. Since this effect occurs at and above the gel-to-liquid-crystalline phase transition, it is suggested that membrane fluidity plays an important role in these interactions.     

Volume Control in Hemodialysis Patients

Cardiovascular disease is the main cause of the high mortality of dialysis patients and is largely due to poor control of blood pressure. Establishing and maintaining normal extracellular volume (ECV) is required to achieve normotension. The dry weight concept links ECV and blood pressure by a simple clinical relationship. Dry weight is the ideal postdialysis weight that allows a constantly normal blood pressure to be maintained without using antihypertensive medications. Maintenance of normal ECV requires control of salt intake to reduce interdialytic weight gain ( i.e., saline overload) combined with the diffusive and convective removal of salt and water from the body during dialysis sessions. Several problems are to be faced when using the dry weight method. Clinical evaluation must take into account the following confounding factors: weight varies with nutrition, clinical symptoms are unspecific and sometimes discordant, and there is a lag time between ECV and blood pressure changes. On the other hand, achievement of dry weight is hampered by dialysis times that are too short (and weight gains that are too high), by antihypertensive medications, and by poor heart conditions. A longer session time allows for a slower, easier, and more comfortable ultrafiltration.     

Complete study of a millifluidic flow battery using iodide and ferricyanide ions: modeling,effect of the flow and kinetics

In this work, we present a comprehensive study dealing with the modeling of the conversion process occurring in a redox flow cell. Experiments are carried out on an original millifluidic flow battery with ferrocyanide and iodide as electrolytes. A simulation model supports the experimental data. In flow, intensity recovery is limited by the mass transfer. Thanks to diffusion, at low Peclet, the conversion is complete. On the contrary, at high Peclet, the convection prevents the diffusion of species and induces a conversion drop. A quantitative agreement is found between theoretic model and experiment both on current and on power curves. The originality of our work is to take into account the kinetics of the redox reaction at the electrodes. We evidence a new regime where the current intensity is constant as a function of the Peclet number. The maximal recovered power is obtained at a given flow rate and not at very high flow rate. This work paves the road for the optimization of the conversion process and for the measurements of the thermodynamic parameters involved in the redox process such as kinetic parameters at the electrodes.     

Prototyping and Validating a Non-immersive Virtual Reality Serious Game for Healthcare Fire Safety Training

Fire Technology - In a healthcare context, the success of a fire safety procedure in a real-life emergency mainly depends on staff decisions and actions. One of the factors influencing staff...     

In Silico Identification of Potential Druggable Binding Sites on CIN85 SH3 Domain

Protein-protein interactions (PPIs) play a pivotal role in the regulation of many physiological processes. The dysfunction of some PPIs interactions led to the alteration of different biological pathways causing various diseases including cancer. In this context, the inhibition of PPIs represents an attractive strategy for the design of new antitumoral agents. In recent years, computational approaches were successfully used to study the interactions between proteins, providing useful hints for the design of small molecules able to modulate PPIs. Targeting PPIs presents several challenges mainly due to the large and flat binding surface that lack the typical binding pockets of traditional drug targets. Despite these hurdles, substantial progress has been made in the last decade resulting in the identification of PPI modulators where some of them even found clinical use. This study focuses on MUC1-CIN85 PPI which is involved in the migration and invasion of cancer cells. Particularly, we investigated the presence of druggable binding sites on the CIN85 surface which provided new insights for the structure-based design of novel MUC1-CIN85 PPI inhibitors as anti-metastatic agents.