Color Magnetism in Non-Abelian Vortex Matter

We propose color magnetism as a generalization of the ordinary Heisenberg (anti-)ferro magnets on a triangular lattice. Vortex matter consisting of an Abrikosov lattice of non-Abelian vortices with color magnetic fluxes shows a color ferro or anti-ferro magnetism, depending on the interaction among the vortex sites. A prime example is a non-Abelian vortex lattice in rotating dense quark matter, showing a color ferromagnetism. We show that the low-energy effective theory for the vortex lattice system in the color ferromagnetic phase is described by a 3+1 dimensional $CP^{N-1}$ nonlinear sigma model with spatially anisotropic couplings. We identify gapless excitations independent from Tkachenko modes as color magnons, that is, Nambu-Goldstone modes propagating in the vortex lattice with an anisotropic linear dispersion relation $\omega_p^2 = c_{xy}^2(p_x^2+p_y^2) + c_z^2 p_z^2$. We calculate the transition temperature between the ordered and disordered phases, and apply it to dense quark matter. We also identify the order parameter spaces for color anti-ferromagnets.Comment: 7 pages, no figures, published versio

Challenges in machine perfusion preservation for liver grafts from donation after circulatory death

Donation after circulatory death (DCD) is a promising solution to the critical shortage of donor graft tissue. Maintaining organ viability after donation until transplantation is essential for optimal graft function and survival. To date, static cold storage is the most widely used form of preservation in clinical practice. However, ischemic damage present in DCD grafts jeopardizes organ viability during cold storage, and whether static cold storage is the most effective method to prevent deterioration of organ quality in the increasing numbers of organs from DCD is unknown. Here we describe the historical background of DCD liver grafts and a new preservation method for experimental and clinical transplantation. To prevent ischemia-reperfusion injury in DCD liver grafts, a hypothermic machine perfusion (HMP) technique has recently been developed and may be superior to static cold preservation. We present evidence supporting the need for improving liver perfusion performance and discuss how doing so will benefit liver transplantation recipients

Controllable Immunosuppression in Pigs as a Basis for Preclinical Studies on Human Cell Therapy

Along with a growing interest in regenerative medicine, pigs are becoming a popular model for preclinical studies on human cell therapy. Due to pharmaceutical species difference and inability to self-medicate, specific modification and care are necessary in immunosuppressive regimen for pigs. Here, we summarize recent literature on immunosuppression in pigs for experimental transplantation. Based on literature and our own experiences, a practical protocol has been proposed in this report. In early studies of allogeneic organ transplantation, recipient pigs were administered cyclosporine or tacrolimus, and mycophenolate mofetil at slightly higher dose than that in human cases, because of relatively poor effectiveness of the drugs in pigs. Steroids may be effective but sometimes can cause debilitating side effects. Cell transplantation studies follow the basic protocol, but it remains to be clarified whether the smaller graft mass, even if it is xenogeneic, requires the same scale of immunosuppression as organ transplantation. To obtain reliable results, the use of gastrostomy tube and blood trough level monitoring are highly recommended. Nonpharmaceutical immunosuppression such as thymic intervention and the use of severe combined immunodeficient pigs have also been discussed

A Novel Strategy for Xeno-Regenerative Therapy

The shortage of organs for transplantation is of critical importance worldwide. Xenotransplantation or xeno-embryonic organ transplantation can stably supply organs and is considered to be an established alternative treatment. Regenerative medicine is another option, and recent advances in stem cell research have enabled the reproduction of miniature organs, called organoids, derived in vitro from human induced pluripotent stem cells. However, the in vitro production of large and complex organs that can efficiently function in vivo is not yet accomplished. We proposed a novel strategy for xenotransplantation in which a chimeric kidney is constructed by injecting human nephron progenitor cells into a porcine embryonic kidney, thereby eliminating pig nephron progenitor cells and allowing transplantation into a human and long-term survival. In this chapter, we discussed advantages and pitfalls of xenotransplantation and xeno-embryonic kidney transplantation. Recent attempts of human organoids and blastocyst complementation were reviewed. Finally, we proposed our novel xeno-regenerative therapeutic strategy

Phosphorus Particle Composite Plating with Ni-P Alloy Matrix

Ni-P alloy films containing phosphorus particles (called Ni-P alloy composite films) were fabricated by electrodeposition and were subsequently subjected to heat-treatment. Their compositions and microstructures were characterized, and their friction properties were evaluated using a ball-on-plate method. Composite electroplating in the nickel sulfate and chloride bath containing phosphorus acid and micrometer-sized phosphorus particles resulted in the Ni-P alloy coating with enhanced deposit phosphorus content. The phosphorus content of the films increased with increasing phosphorus particle concentration in the composite plating baths, reaching a maximum value of 29.0 atom %. The phosphorus particles were homogeneously distributed in this Ni- 29.0 atom % P alloy composite film. Heat-treatment converted the phases of the alloy composite films from an amorphous phase to stable crystalline phases, which are the same as those in the Ni- P binary alloy phase diagram. The friction coefficients of the Ni- P alloy films increased with increasing cycle number, whereas those of the Ni- P alloy composite films remained relatively constant. The alloy composite films had lower friction coefficients than the Ni- P alloy films both before and after heat-treatment. These results indicate that phosphorus particles are beneficial for maintaining a lower and stable friction coefficient during the ball-on-plate reciprocating friction test.ArticleJOURNAL OF THE ELECTROCHEMICAL SOCIETY 156: D283-D286(2009)journal articl

Pigs as Models of Preclinical Studies and In Vivo Bioreactors for Generation of Human Organs

Pigs are valuable and essential large animal models for human medical applications, including for stem cell therapy. Moreover, substantial effort has been made to directly engraft genetically engineered pig organs in the human body and to use pigs as in vivo bioreactors for the growth and development of human cells, tissue, or organs. However, engraftment of human cells in pigs has not yet been achieved. Although severe combined immunodeficient pigs have been developed, which can accept human biological materials, these pigs do not have practical value at present owing to difficulty in their care. To overcome these current limitations, we have proposed the generation of operational immunodeficient pig models by simply removing the thymus and spleen, enabling the long-term accommodation of human tissue. In this review, we summarize research progress on xenotransplantation animal models that accept human cells, tissues, or organs

Rat small intestinal transplantation: a comparison of the cuff and hand-suture methods.

The rat model is ideal for investigating various reactions to small intestinal transplantation (SIT). The conventional surgical model (hand-suture method), however, requires microsurgical techniques and remains difficult for beginners to perform at a high success rate. We have employed the SIT model using the cuff method, by which the vessels are anastomosed without sutures. All of the fellows who used the hand-suture models needed over 8 +/- 5.8 months until they achieved a 70% success rate. In contrast, the fellows employing the cuff method mastered SIT models after 6 weeks' practice. The cuff technique is a simplified and quickly mastered alternative to the hand-suture method that may be desirable for researchers who wish to apply the method to SIT experiments and whose primary purpose is not microsurgery.</p