Phospholipid Polymers

Ishihara, Kazuhíko

doi:10.1002/0471440264.pst574

Cited by 7 publications

(6 citation statements)

References 130 publications

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“…We have also tested the impact on the cosmogenic neutrino flux. A two-component model as shown in Figure 6 for α p = 2.5 in combination with the GRB strong evolution would lead to a very large production of cosmogenic neutrinos close to the current bound (Ishihara 2012), which should be testable in the very near future. This is a generic feature common to all models with strong source evolution and a pronounced rise after the ankle in the cosmic ray spectrum; see, e.g., Kotera et al (2010).…”

Section: Parameter Space Study Of the Cosmicmentioning

confidence: 97%

Uhecr Escape Mechanisms for Protons and Neutrons From Gamma-Ray Bursts, and the Cosmic-Ray-Neutrino Connection

Baerwald

Bustamante

Winter

2013

ApJ

118

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The paradigm that gamma-ray burst (GRB) fireballs are the sources of the ultra-high energy cosmic rays (UHECRs) is being probed by neutrino observations. Very stringent bounds can be obtained from the cosmic ray (proton)-neutrino connection, assuming that the UHECRs escape as neutrons. In this study, we identify three different regimes as a function of the fireball parameters: the standard "one neutrino per cosmic ray" case, the optically thick (to neutron escape) case, and the case where leakage of protons from the boundaries of the shells (direct escape) dominates. In the optically thick regime, photomeson production is very efficient, and more neutrinos will be emitted per cosmic ray than in the standard case, whereas in the direct escape-dominated regime, more cosmic rays than neutrinos will be emitted. We demonstrate that, for efficient proton acceleration, which is required to describe the observed UHECR spectrum, the standard case only applies to a very narrow region of the fireball parameter space. We illustrate with several observed examples that conclusions on the cosmic rayneutrino connection will depend on the actual burst parameters. We show that the definition of the pion production efficiency currently used by the IceCube collaboration underestimates the neutrino production in the optically thick case. Finally, we point out that the direct escape component leads to a spectral break in the cosmic ray spectrum emitted from a single source. The resulting "twocomponent model" can be used to even more strongly pronounce the spectral features of the observed UHECR spectrum than the dip model.

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Section: Parameter Space Study Of the Cosmicmentioning

confidence: 97%

Uhecr Escape Mechanisms for Protons and Neutrons From Gamma-Ray Bursts, and the Cosmic-Ray-Neutrino Connection

Baerwald

Bustamante

Winter

2013

ApJ

118

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“…Polymerization of MPC and its derivatives are summarized in this review article [15]. MPC polymers are soluble in water, and the solubility can be easily adjusted by changing the structure and fraction of the comonomers.…”

Section: Development Of Mpc Polymer Sciencementioning

confidence: 99%

Cell membrane-inspired phospholipid polymers for developing medical devices with excellent biointerfaces

Iwasaki

Ishihara

2012

Science and Technology of Advanced Materials

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261

216

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This review article describes fundamental aspects of cell membrane-inspired phospholipid polymers and their usefulness in the development of medical devices. Since the early 1990s, polymers composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) units have been considered in the preparation of biomaterials. MPC polymers can provide an artificial cell membrane structure at the surface and serve as excellent biointerfaces between artificial and biological systems. They have also been applied in the surface modification of some medical devices including long-term implantable artificial organs. An MPC polymer biointerface can suppress unfavorable biological reactions such as protein adsorption and cell adhesion -in other words, specific biomolecules immobilized on an MPC polymer surface retain their original functions. MPC polymers are also being increasingly used for creating biointerfaces with artificial cell membrane structures.

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“…This renders them ideal groups for conferring ''non-fouling" or protective properties to molecules and surfaces. Kazuhiko Ishihara was one of the first to identify such protective properties of zwitter-ion groups with his early studies of surface-immobilized poly(2-methacryloyloxyethyl phosphorylcholine) (''polyMPC") grafted polymers [34]. In conclusion, zwitter-ion polymers may offer a suitable ''replacement" for PEG in some PEGylated drugs in the future.…”

Section: Statement Of Significancementioning

confidence: 99%

The early days of PEG and PEGylation (1970s–1990s)

Hoffman

2016

Acta Biomaterialia

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Phospholipid Polymers

Cited by 7 publications

References 130 publications

Uhecr Escape Mechanisms for Protons and Neutrons From Gamma-Ray Bursts, and the Cosmic-Ray-Neutrino Connection

Uhecr Escape Mechanisms for Protons and Neutrons From Gamma-Ray Bursts, and the Cosmic-Ray-Neutrino Connection

Cell membrane-inspired phospholipid polymers for developing medical devices with excellent biointerfaces

The early days of PEG and PEGylation (1970s–1990s)

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