Antigen Retrieval for Light and Electron Microscopy

Heat-induced antigen retrieval (HIAR) method reported by Shi et al. in 1991 has greatly contributed not only to immunohistochemistry but also to studying gene expressions using archived formalin-fixed and paraffin-embedded (FFPE) specimens. Heating cleaves crosslinks (methylene bridges) in formaldehyde-fixed proteins and extends polypeptides to expose epitopes hidden in the inner portion of antigens or covered by adjacent macromolecules. In this chapter, the following topics are described to reconsider the concept of immunohistochemistry flexibly and to apply HIAR for further immunological studies using a variety of specimens: (1) antigen-antibody interactions in tissues; (2) mechanisms of chemical fixation with formaldehyde, glutaraldehyde, and osmium tetroxide; (3) unmasking of epitopes using HIAR for specimens fixed with chemical fixatives, including highly masked epitopes; (4) a standardized fixative for immunoelectron microscopy-based HIAR; (5) HIAR for conventionally processed electron microscopy specimens embedded in epoxy resins; and (6) effects of antibody diluents on immunohistochemistry

Synthesis of poly(conjugated ester)s by ring-opening polymerization of cyclic hemiacetal ester bearing acryl skeleton

Available online 20 August 2019Ring-opening polymerization (ROP) of 2,6-dimethyl-5-methylene-1,3-dioxan-4-one (DMDO), a cyclic hemiacetal ester containing an acrylate skeleton, was investigated. Although the ROPs catalyzed by tin(II) 2-ethylhexanoate [Sn(Oct)(2)] and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) did not yield polymeric products, diphenyl phosphate (DPP) functioned a catalyst for the ROP through acyl scission accompanying with the elimination of acetaldehyde at 50 degrees C and 80 degrees C. The resulting polymer was a poly(conjugated ester) that had similar structure to the polymer of alpha-methylene-beta-butyrolactone (M beta BL), an alpha-exomethylene lactone with four-membered ring. Copolymerizations of epsilon-caprolactone and delta-valerolactone were also performed to yield the corresponding polyesters. The chemoselective main chain scission of the copolymers at the conjugated ester units were achieved by conjugate substitution reaction with benzyl mercaptan. Although the ROP of DMDO left a problem in the control of molecular weight, DMDO exhibited a potential as an easier accessible monomer alternative to M beta BL for the preparation of bio- and chemo-degradable polyesters.ArticleEUROPEAN POLYMER JOURNAL.120:109185(2019)journal articl

Plane Formation by Synchronous Mobile Robots without Chirality

We consider a distributed system consisting of autonomous mobile computing entities called robots moving in the three-dimensional space (3D-space). The robots are anonymous, oblivious, fully-synchronous and have neither any access to the global coordinate system nor any explicit communication medium. Each robot cooperates with other robots by observing the positions of other robots in its local coordinate system. One of the most fundamental agreement problems in 3D-space is the plane formation problem that requires the robots to land on a common plane, that is not predefined. This problem is not always solvable because of the impossibility of symmetry breaking. While existing results assume that the robots agree on the handedness of their local coordinate systems, we remove the assumption and consider the robots without chirality. The robots without chirality can never break the symmetry consisting of rotation symmetry and reflection symmetry. Such symmetry in 3D-space is fully described by 17 symmetry types each of which forms a group. We extend the notion of symmetricity [Suzuki and Yamashita, SIAM J. Compt. 1999] [Yamauchi et al., PODC 2016] to cover these 17 symmetry groups. Then we give a characterization of initial configurations from which the fully-synchronous robots without chirality can form a plane in terms of symmetricity