Attenuation correction of SPECT imaging by dual energy method--quantification of 111In-labeled monoclonal anti-tumor antibody localization

Application of radiolabeled monoclonal anti-tumor antibodies for diagnosis and therapy has made remarkable progress in the past few years. Quantification of radiopharmaceutical localization is required adequate attenuation correction in SPECT imaging. Attenuation correction by transmission CT (TCT) data is one of the best method at present time. However, if a patient is moved between TCT and SPECT, this method is no more applicable. We developed a new attenuation correction algorithm by dual energy method, using 99mTc and 111In because of similarity of these linear attenuation coefficients. The new algorithm uses data of TCT with an external source of 99mTc, and requires another data from SPECT of 111In labeled monoclonal anti-tumor antibody, which are simultaneously obtained. TCT results in an attenuation map, which then serves as input into the final intrinsic correction algorithm to uncorrected SPECT data. In chest phantom experiment, the attenuation corrected SPECT images revealed nearly same distribution of actual radioactivity of 111In as compared to that of uncorrected one.     

Synthesis and alpha-glucosidase-inhibiting activity of a new alpha-glucosidase inhibitor, 4-O-alpha-D-glucopyranosylmoranoline and its N-substituted derivatives

Various N-substituted derivatives of 4-O-alpha-D-glucopyranosylmoranoline have been synthesized, and their inhibitory activities against rabbit sucrase and maltase have been measured, as well as their effects on postprandial hyperglycemia in the sucrose-loaded rat, 4-O-alpha-D-Glucopyranosylmoranoline was also shown to have potent hypoglycemic activity in starch-loaded dogs.     

Light polarization in iodine-doped polyvinyl alcohol films

¹²⁹I Mössbauer measurements have been performed on unidirectionally stretched iodinedoped polyvinyl alcohol(PVA) films which are widely used as optical polarizers. In the films iodine is observed to be in the form of I^?, I ₃ ^? , and I ₅ ^? and the stretch of the films increases the abundance of the polyiodides, I ₃ ^? and I ₅ ^? . In the stretched PVA films, it has become clear that the linear polyiodides lie parallel to the stretching direction.     

Chemical structure of iodine-doped polyisoprene

A nonconjugated conducting polymer (1,4-rans-polyisoprene) at different iodine doping levels has been studied with the 27.7-keV Mössbauer resonance of¹²⁹I. At the light doping level, almost all iodines are covalently bonding to the carbon atoms, breaking the double bonds of the main chain. At the medium doping level, other iodine species are found, which are idendified as anion species, l^?, l ₃ ^? and l ₃ ^? .At the heavy doping level, polyiodide anions, l ₃ ^? and l ₅ ^? , increase as compared to the covalently bonding iodine atoms and addtionally molecular iodine l₂ exists.     

Stereochemical analysis of isopentenyl diphosphate isomerase type II from Staphylococcus aureus using chemically synthesized (S)- and (R)-[2-2H]isopentenyl diphosphates

[chemical reaction: see text]. To study the catalysis of isopentenyl diphosphate (IPP) isomerase type II from Staphylococcus aureus, which is a flavoprotein catalyzing the interconversion of IPP and dimethylallyl diphosphate, we have chemically synthesized (S)- and (R)-[2-2H]IPP and carried out stereochemical analysis of the reaction. Our results show that the C-2 deprotonation of IPP by this enzyme is pro-R stereospecific, suggesting a similar stereochemical course as the type I enzyme.     

Studies on the biosynthesis of terrecyclic acid A II confirmation of the cyclization mechanism and hydrogen shifts using [2-2H3]acetate and [213C2H3]acetate

Feeding experiments with [2-³H₃]acetate and [2-¹³C²H₃]acetate in $\text{Aspergillus terreus}$ Thom No. 14 indicated that the hydrogen at C-2 in terrecyclic acid A is incorporated without migration from the precursor acetic acid; the results favour our group's earlier speculation for the cyclization to the tricyclic skeleton in the biosynthetic scheme.     

Experimental study for adsorption and photocatalytic reaction of ethyl methylphosphonate molecule as organophosphorus compound adsorbed at surface of titanium dioxide under UV irradiation in ambient condition

The adsorption and photocatalytic degradation of Ethyl methylphosphonate (EMPA) on powdery TiO₂ film has experimentally investigated using attenuated total reflection-infrared Fourier transform spectroscopy (ATR-FTIR) in ambient condition. Characteristic IR frequency as P-O-C vibration mode as EtO was observed by EMPA adsorbed at the surface of TiO₂. By TiO₂ photocatalysis, the adsorbed EMPA was decomposed to methyl phosphonic acid and phosphoric acid. The increment of IR intensity of which is assigned to Ti–O-P-O-Ti of EMPA was accompanied with increasing the IR peak intensity assigned to MPA. About that, we suggest that the appearance of the Ti–O-P-O-Ti of EMPA by the TiO₂ photocatalysis is regarded as acceleration of the hydrolysis of EMPA by the surface OH groups of TiO₂. The plausible adsorption structure and the photocatalytic reaction mechanism of EMPA at the surface of TiO₂ photocatalyst were elucidated.

     

High-Density Excitons in a Diluted Magnetic Semiconductor: Cd 1 − x Mn x Te

Time-resolved magneto photoluminescence in a diluted magnetic semiconductor Cd 0.9 Mn 0.1 Te has been carried out with varying exciton density from 10 14 to 10 19 cm m 3 . The reduction of the Zeeman shift and that of the magnetic polaron energy was found under strong photoexcitation. The spectral feature is interpreted in terms of the heating of the manganese spin subsystem. Polarization dependence of the spin heating is observed for the first time, revealing the contribution of the spin flip between excitons and magnetic ions to the heating process.