Transplant arteriosclerosis: an enigmatic disease due to a misnomer

Solid organ transplantation across the allogeneic barrier, pioneered by Thomas Starzl, has by now become a common medical procedure. Unfortunately, the number of donor organs lost due to transplant arteriosclerosis (chronic rejection), remains significant and unchanged for decades. We argue that designation of transplant arteriosclerosis as chronic rejection, and its classification as a delayed long-lasting reaction of recipient immune effectors against donor alloantigens have given us a wrong impression that we have identified the necessary cause/pathogenesis of the tissue pathology. However, whatever treatment options we have in the anti-rejection toolbox, despite their success in treating classical rejection, do not work for the transplant arteriosclerosis. Yet, the scientific community has continued to conceptualize and approach the pathology within the alloimmunity model. Due to unproductive research from the alloimmunity and rejection perspective, the number of transplanted hearts lost due to this pathology today is almost the same as it was fifty years ago. We believe that this phenomenon falls under the rubric of linguistic relativity, and that language we chose to name the disease has restricted our cognitive ability to solve the problem. While the initial perception of the transplant arteriosclerosis as chronic rejection was logical and scientific, the subsequent experience revealed that such perception and approach have been fruitless, and likely are incorrect. Considering our tragic failure to prevent and treat the delayed arterial pathology of donor organs using all available knowledge on alloimmunity and rejection, we must finally disassociate the former from the latter. The only way to start this uncomfortable process is to change the words we are using; particularly, the words we chose to name the disease. We have to step out of the alloimmunity rejection box.Comment: 19 pages, 2 figure

Magnetic properties of ferrofluid emulsions: The effect of droplet elongation

The paper is concerned with a theoretical explanation of the experimentally observed effect of non-monotonic field dependence of the effective magnetic permeability of ferrofluid emulsion. In a weak magnetic field, the growth of the induced droplet magnetic moment is faster than the linear one due to the droplet elongation accompanied by the reduction of the demagnetizing field. Thus, the emulsion magnetic permeability increases in weak magnetic fields. Further strengthening of the external magnetic field cannot lead to a significant decrease of the demagnetizing field, as the droplets are already highly elongated. On the other hand, the magnetic susceptibility of the ferrofluid reduces with the field strength. Hence, the effective magnetic permeability of the ferrofluid emulsion starts decreasing. The developed theoretical model describes well the experimental observations

Magnetic Permeability of Inverse Ferrofluid Emulsion: An Influence of Interdroplet Interaction

A theoretical model has been developed to describe the weak-field growth of the magnetic susceptibility of inverse ferrofluid emulsion provided the interdroplet interaction is taken into account. The presented mean-field approach predicts a nonlinear dependence of the initial magnetic susceptibility on the droplet concentration and provides a good agreement with experimental data. © 2018, Institute of Physics, University of Latvia.The work is supported by the Ministry of Education and Science of the Russian Federation (contract no. 02.A03.21.0006, project no. 3.1438.2017/4.6)

Adsorption-desorption kinetics in nanoscopically confined oligomer films under shear

The method of molecular dynamics computer simulations is employed to study oligomer melts confined in ultra-thin films and subjected to shear. The focus is on the self-diffusion of oligomers near attractive surfaces and on their desorption, together with the effects of increasing energy of adsorption and shear. It is found that the mobility of the oligomers near an attractive surface is strongly decreased. Moreover, although shearing the system forces the chains to stretch parallel to the surfaces and thus increase the energy of adsorption per chain, flow also promotes desorption. The study of chain desorption kinetics reveals the molecular processes responsible for the enhancement of desorption under shear. They involve sequences of conformations starting with a desorbed tail and proceeding in a very fast, correlated, segment-by-segment manner to the desorption of the oligomers from the surfaces.

Phase behavior and structure formation of hairy-rod supramolecules

Phase behavior and microstructure formation of rod and coil molecules, which can associate to form hairy-rod polymeric supramolecules, are addressed theoretically. Association induces considerable compatibility enhancement between the rod and coil molecules and various microscopically ordered structures can appear in the compatibility region. The equilibria between microphase-separated states, the coil-rich isotropic liquid and the rod-rich nematic are discussed in detail. In the regime where hairy-rod supramolecules with a high grafting density appear as a result of the association, three phase diagram types are possible depending on the value of the association energy. In the low grafting density regime only the lamellar microstructure is proven to be stable