ObjectiveNoninvasive imaging by positron emission tomography (PET) of macrophages in inflamed joints of patients with rheumatoid arthritis (RA) may allow early detection of disease activity. We undertook this study to investigate whether rheumatoid synovitis can be visualized by PET using the tracer 11C‐(R)‐PK11195, which binds to peripheral benzodiazepine receptors (PBRs) on macrophages.MethodsKnee joints of 11 RA patients with active arthritis of at least 1 knee joint were imaged with 11C‐(R)‐PK11195 PET. Tissue uptake of 11C‐(R)‐PK11195 was quantified. PET was followed by arthroscopy of the most inflamed knee joint of each RA patient. Synovial tissue samples were subjected to immunohistochemical staining.Results11C‐(R)‐PK11195 uptake on the PET scans was significantly higher in severely inflamed joints than in joints with moderate or mild signs of inflammation. In addition, tracer uptake in contralateral uninflamed knee joints of RA patients was significantly higher than in uninflamed joints of control patients without inflammatory joint disease, suggesting the presence of subclinical disease activity. PET tracer uptake in joints correlated significantly with PBR staining in the sublining of synovial tissue. PBR staining correlated significantly with CD68 staining of macrophages.Conclusion11C‐(R)‐PK11195 PET imaging allows noninvasive in vivo imaging of macrophages in rheumatoid synovitis and possibly even in subclinical synovitis. Noninvasive visualization of macrophages may be useful both for detecting early synovitis and for monitoring synovitis activity during treatment.
ABSTRACT:The radical graft polymerization of vinyl monomers from inorganic ultrafine particles, such as silica, titanium oxide, and ferrite, by use of azo groups introduced onto their surface was investigated. The introduction of azo groups onto the ultrafine particles was achieved by the reaction of glycidyl groups, which were introduced by the reaction of hydroxyl groups on the surface with 3-glycidoxypropyltrimethoxysilane, with 4,4'-azobis(4-cyanopentanoic acid). The amounts of azo groups introduced onto silica, titanium oxide, and ferrite were determined to be 0.07, 0.05, and 0.03 mmol g ·· 1 , respectively. The polymerization of vinyl monomers, such as methyl methacrylate (MMA), styrene, and N-vinylcarbazole (NVC), was found to be initiated by radicals formed by the decomposition of the azo groups. During the polymerization, the polymer was effectively grafted onto these surfaces through propagation from the surfaces; the percentage of grafting of polyMMA onto silica, titanium oxide, and ferrite reached to 45
SUVmax, a metabolic semiquantitative parameter, shows a significant correlation with the molecular subtype of breast cancer, and is useful for predicting the luminal A or HER2-positive subtype.
A stress-operated memory device consisting of an ellipsoidal magnetic particle array and an electrostrictive grid is proposed. In the device, the magnetic state of the particle can be controlled only by the magnetostriction effect. Each particle is located at the intersection of the grid and has an in-plane uniaxial anisotropy. A pair of electric contacts is connected to the end of each wire. In the writing process, the driving voltages are simultaneously applied to two pairs of the selected contacts. This allows to apply a local electric field whose direction and amplitude can be regulated by varying the voltage intensity and polarity. The exerting stress on the magnetic particle results in the linear magnetostriction and hence an additional anisotropy energy in the particle. The in-plane total energy minimum, corresponding to the magnetization direction, follows the local electric field. Consequently the magnetization of the single magnetic particle located at the intersection can therefore be selectively switched.
Poly(ethylene glycol) (PEG) having different molecular weight was successfully grafted onto carbon black surface by direct condensation of terminal hydroxyl groups of PEG with carboxyl groups on the surface using N,N'dicyclohexylcarbodiimide as a condensing agent. The electric resistance of a composite prepared from PEG and PEGgrafted carbon black drastically increased to 10 3-10 4 times of initial resistance in humidity and vapor of methanol, and ethanol, which are good solvent of PEG, and returned immediately to initial resistance when it was transferred in dry air. But the change of electric resistance of the composite was hardly observed in hexane and toluene vapor, which are poor solvent of PEG. The logarithm of electric resistance is linearly proportional to relative humidity. The sensitivity of electric resistance decreased with increasing molecular weight of PEG. In addition, the electric resistance of the composite from PEG-grafted carbon black lost the responsibility against solvent vapor above melting point of PEG. By crosslinking of the composite from PEG-grafted carbon black with triisocyanate, the responsibility against solvent vapor disappeared completely. These results indicated that the crystalline structure of PEG plays an important role on the responsibility of electric resistance of PEG-grafted carbon blacks against humidity and alcohol vapor.
The grafting of polymers onto a carbon black surface based on the trapping of polymer radicals by polycondensed aromatic rings of the surface was investigated. It was found that polymer radicals formed by the thermal decomposition of azo-polymer, peroxy-polymer and 2,2,6,6-tetramethylpiperidinyl-1-oxy-terminated polymer are successfully captured by a carbon black surface to give the corresponding polymer-grafted carbon blacks. The grafting of polymers onto carbon black was also achieved by the trapping of polymer radicals formed by the redox reaction of ceric ions with polymers having hydroxyl groups. It was concluded that surface grafting of polymers onto carbon black is effective when there are few functional groups. The electrical resistance of poly(ethylene oxide) (PEO)-grafted carbon black thus obtained is increased drastically to about 10 4-10 5 times the initial resistance at the melting point of PEO. This may be due to a widening of the gaps between the carbon black particles by melting of PEO. In addition, it was found that the electrical resistance of a crystalline poly(ethylene imine) (PEI)-grafted carbon black drastically increased to 10 3-10 4 times the initial resistance in methanol, ethanol and water vapor, but hardly any change in electrical resistance was observed in nhexane or toluene vapor. These results suggest the possibility of detecting a slight change in the crystalline structure of PEI upon absorption of solvent vapor as a large increase in the electrical resistance of the polymer-grafted carbon black.
Willows usually establish on wet substrates with fine sediments at sites that are created by large disturbances, but suitable microsites are spatially and temporally limited. Thus, we hypothesized that willow seeds are selectively dispersed to suitable microsites, such as those with a wet substrate, rather than unsuitable microsites, such as those with a dry substrate, with seedling establishment mediated by the cottony hairs attached to seeds (directed dispersal). To test our hypothesis, we compared several recruitmentrelated traits, including buoyancy, germination, and trapping at favorable microsites, in seeds of the riparian willows Salix sachalinensis and S. integra with and without cottony hairs in laboratory and field experiments. In both field and laboratory experiments, more seeds with cottony hairs were trapped in water and wet sand than in dry sand, in which no seeds of either species germinated. These results indicate that cottony hairs facilitate the recruitment of seeds to microsites favorable for seed germination and help seeds avoid unfavorable microsites. On the water surface, 17.6% of S. sachalinensis seeds and 68.0% S. integra seeds with cottony hairs floated for more than 6 days, whereas all seeds without cottony hairs sank immediately after being placed on the water surface. These results suggest that cottony hairs facilitate long-distance dispersal via flowing water and also help avoid germination under water, where willow seedlings fail to establish. Seeds of the two willow species were released from the cottony hairs and germinated immediately after the seeds were placed on wet sand, but not after placement on water or dry sand. These results suggest that the seeds are released from the cottony hairs when the hairs become wet and the seeds are striking to a suitable microsite for seedling establishment, such as wet sand. In riparian willows, the cottony hairs promote directed dispersal by moving seeds to discrete and predictable microsites where the seedling establishment is disproportionately high.
ABSTRACT:Radical graft polymerization from ultrafine silica surface was investigated. A redox system consisting of eerie ion and the silica particles carrying reducing groups, such as alcoholic hydroxyl, amino, and mercapto groups, was capable of initiating the radical polymerization of acrylamide (AAm). The introduction of alcoholic hydroxyl groups onto the surface was achieved by the treatment of the silica with 3-glycidoxypropyltrimethoxysilane in acidic condition in water. Amino or mercapto groups were introduced onto the silica by reactions of surface silanol groups w.ith 3-aminopropyltriethoxysilane or 3-mercaptopropyltrimethoxysilane, respectively. The initiating ability of the redox system changed, depending on the reducing groups on the silica surface, in the following order: alcoholic hydroxyl group< amino group< mercapto group. In the above redox polymerization, polyacrylamide was grafted onto the silica based on the propagation of the polymer from the radicals formed by the reaction of eerie ion with alcoholic hydroxyl, amino, or mercapto groups. The percentage of grafting onto the silica reached about 25%. The silica obtained from the redox graft polymerization gave a stable colloidal dispersion in water. KEY WORDSUltrafine Particle / Silica / Radical Grafting / Redox Polymerization/ Ceric Ion/ Acrylamide / Silane Coupling Agent/ Colloidal Dispersion / In the preceding paper, we reported the grafting of poly(propylene glycol) onto an ultrafine ferrite particle by the reaction of hydroxyl groups on the surface with isocyanatecapped poly(propylene glycol). 1 The percentage of grafting, however, was less than 15-%. As described in the review paper, it is required to initiate the graft polymerization from an active site (initiating group) introduced onto a particle surface to obtain polymer-grafted carbon black with a higher percentage of grafting.2 For instance, in the anionic ring-opening polymerization of {.i-propiolactone (PL) initiated by potassium carboxylate groups on carbon black, the percentage of grafting of poly-PL increased to about 100%.3We succeeded in the radical graft polymerization of water-soluble vinyl monomers onto carbon black initiated by a redox system consisting of eerie ions and alcoholic hydroxyl groups on the surface. 4 • 5 In the redox polymerization of acrylamide (AAm), poly-AAm was effectively grafted from carbon black based on the propagation of the polymer from radicals formed by the reaction of eerie ions with alcoholic hydroxyl groups.In the present paper, we report the graft polymerization of AAm from an ultrafine silica 475 N. TSUBOKAWA et al. initiated by a redox system consisting of eerie ion and reducing groups, such as alcoholic hydroxyl, amino, and mercapto groups, introduced onto the surface. Furthermore, the ~o-Ji-R-CH -XH
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