Interplay of vitrification and ice formation in a cryoprotectant aqueous solution at low temperature.

The proneness of water to crystallize is a major obstacle to understanding its putative exotic behavior in the supercooled state. It also represents a strong practical limitation to cryopreservation of biological systems. Adding some concentration of glycerol, which has a cryoprotective effect preventing, to some degree, water crystallization, has been proposed as a possible way out, provided the concentration is small enough for water to retain some of its bulk character and/or for limiting the damage caused by glycerol on living organisms.

CSPEC: The cold chopper spectrometer of the ESS, a detailed overview prior to commissioning.

CSPEC is the cold chopper spectrometer of the European Spallation Source (ESS) and will come online with the ESS beam on the target. CSPEC will be the first cold chopper spectrometer on a long pulsed spallation source, which provides great opportunities in terms of signal to noise and novel measuring schemes. We provide a detailed overview of the instrument, scientific design considerations, and engineering requirements.

Hemoglobin diffusion and the dynamics of oxygen capture by red blood cells.

Translational diffusion of macromolecules in cell is generally assumed to be anomalous due high macromolecular crowding of the milieu. Red blood cells are a special case of cells filled quasi exclusively (95% of the dry weight of the cell) with an almost spherical protein: hemoglobin. Hemoglobin diffusion has since a long time been recognized as facilitating the rate of oxygen diffusion through a solution.

Conformation of the Poly(ethylene Glycol) Chains in DiPEGylated Hemoglobin Specifically Probed by SANS: Correlation with PEG Length and in Vivo Efficiency.

Cell-free hemoglobin (Hb)-based oxygen carriers have long been proposed as blood substitutes but their clinical use remains tricky due to problems of inefficiency and/or toxicity. Conjugation of Hb with the biocompatible polymer poly(ethylene glycol) (PEG) greatly improved their performance. However, physiological data suggested a polymer molecular weight (Mw) threshold of about 10 kDa, beyond which the grafting of two PEG chains no longer improves efficiency and nontoxicity of diPEG/Hb conjugates.