Vol.12,

A radiochemical procedure used to separate and purify trace concentration thorium produced in heavy ion reaction with uranium targets is presented. The procedure can rapidly yield thorium fraction suitable for gamma-ray spectroscopy studies. The resultant gamma-ray spectra showed that Th was isolated from a large number of elements produced in the reaction, and there were only a few contaminating activities of isotopes of Sc, Cd, In, etc. The decontamination factors for the main reaction products are given.

201

In the batch experiment with W, Ta, Hf, Lu and Mo as radiotracers, a new rapid radiochemical isolation procedure for element tungsten has been developed by using radiochemical separation method and γ spectrum measurement technique. With Voltalef powder carried 2% (W/V) BPHA(Benzoylphenylhydroxylamine)-C₅H₁₁OH (iso-amyl-alcohol) organic solution, radioactive W was adsorbed on the Voltalef column in the 4 mol/L hydrochloric acid system. Hf, Lu and Mo fractions passed through the Voltalef column rapidly and partial Ta activities retained on the Voltalef column, respectively. Following this, W fraction was eluted completely with 1%Na₃C₆H₅O₇(sodium citrate)-5%(W/V) NH₄OH solution and no Hf, Lu, Ta and Mo activities passed through the Voltalef extraction chromatographic column. The procedure was simultaneously used to isolate W from Er target bombarded with a low energy ¹²C beams. By means of this separation system, it is one of the possible way to develop an isolation procedure of Sg, supposing the chemical property of Sg is similar to that of tungsten.

247

Conjugations of 6-Boc-hydrazinopyridine-3-carboxylic acid (Boc-HYNIC) with RC-160 [Lys5, Boc] using different coupling methods were studied. After deprotection, the resulted peptide conjugates were purified by RP-HPLC and characterized by Fab-MS. Combination with different coligands, ^99mTc labeling of HYNIC modified RC-160 conjugate was carried out with high radiolabeling yield (>95%). In vitro stability studies indicated that the final radio-compound remained stable at least up to 20 h when nicotinic acid (NA) used as second coligand (tricine/NA).

283

A method for labeling polypeptide (insulin) with technetium-99(^99mTc) was established without marked loss of biological activity. Following reduction of intrinsic disulfide bonds by mercaptoethanol and purification on a Sephadex G50 column, the polypeptide was labeled with ^99mTc by transchelation from methylene diphospho-nate (MDP). ^99mTc labeled insulin was identified by thin layer chromatograph (TLC) and the change of blood sugar of mice injected, their hypoglycemic shock symptom was also observed. Six hours after labeling, the dissociation of labeled insulin was only 3%, From then on to 24 h, there was no more dissociation. The blood sugar concentration of mice injected with the mercaptoethanol-reduced insulin was (5.0±3.2)μmol·L^-1, while those injected with the original insulin was (1.4±1.2)µmol·L^-1, the difference was significant (Q test, p<0.01). Blood sugar concentration of the mice was 0.3±0.2µmol·L^-1 for the labeled insulin, and was about the same with that for the original insulin. The labeling efficiency was 74.31% for the labeled insulin, whereas the original insulin cannot be labeled with ^99mTc. The result suggests that while disulfide bonds of polypeptide were reduced by mercaptoethanol, it became free sulfhydryl group, and its bioactivity descended. Then free sulfhydryl group was chelated with ^99mTc under mild condition, restablishing the disulfide bond, therefore, the bioactivity came back. The ^99mTc-labeled insulin was stable during 24 h.

278

The ligand of N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4'-iodophenyl) nortropane (FP-β-CIT) and mesylate precursor were synthesized by hydrolysis of cocaine, followed by dehydration, esterification, Grignard reaction, N-demethylation, iodination, N-alkylation with 3-bromopropanol and methylsulfonylation. Finally, ¹⁸F-FP-β-CIT was prepared by nucleophilic fluorination of the mesylate with K¹⁸F/K_2.2.2 (Kryptofix). The labeling yield of ¹⁸F-FP-β-CIT is 25%~30%. The total radiochemical yield of this compound, calculated from the end of bombardment (EOB) with decay correction, is 10%~12% with a synthesis time of 100~110min. The radiochemical purity of ¹⁸F-FP-β-CIT is greater than 90%, and this compound in aqueous solution is also stable for more than 4 hours at room temperature. It is stable enough for clinical study.

211

S-(-)-N-[(1-ethyl-2-pyrrolidinyl)methyl]-5-iodo-2,3-dimethoxybenzamide (proposed generic name, epidepride) is a very potent dopamine D2 antagonist. It was synthesized by five steps from 3-methoxysalicylic acid. [¹³¹I]epidepride was obtained in 97.3% radiochemical yields from the corresponding 5-(tributyltin) derivative using hydrogen peroxide as the oxidant. The aryltin precursor was prepared from non-labelled epidepride by palladium-catalyzed stannylation using bis(tri-n-butyltin) in triethylamine. [¹³¹I]epidepride was stable under 4°C, and partition coefficient was 72.3 at pH 7.40. The biodistribution study in rats exihibited high localization in the striatum of the brain with the striatum/cerebellum ratio reaching 237/1 at 320 min postinjection. All these results suggest that [¹³¹I]epidepride may be used widely as a useful dopamine D2 receptor imaging agent for SPECT.

285

The blistering and flaking behavior of many kinds of amorphous alloys under helium ion bombardment at room temperature was investigated. Helium ions with energies of 40 keV and 60keV were implanted within the fluence range (1.0~4.0)×10¹⁸ ions/cm². The surface topography of samples after irradiation was observed by using a scanning electron microscope. The diameter of blister and the thickness of exfoliated blister lids were measured. The results showed that many kinds of surface topography characteristics appeared for different fluences, energies and amorphous alloys, such as flaking, blistering, exfoliation, blister rupture, secondgeneration blistering and porous structure. The dependence of surface damage modes and the critical fluence for the onset of blistering and flaking on the sort of materials and ion energy was discussed.

259

An experimental method to study the influence of surface contamination of a thinned, backside illuminated charge-coupled device(CCD) upon its quantum efficiency in soft X-ray region is suggested. A transmission grating spectrometer(TGS), in which the transmission grating is coupled to a thinned, backside illuminated charge coupled device, is used to measure the continuum X-ray emission from the end of cylindrical target irradiated by laser. In the measured spectra, only the carbon K absorption edge at wavelength of 4.4 nm due to condensation of the vacuum oil on the CCD surface is clearly seen. The surface contamination is considered as an effective "carbon filter" and the filter absorption to correct the quantum efficiency of the CCD camera is taken into account. The effective thickness of the carbon filter is determined by comparing the jump height of the measured spectra at 4.4 nm with those of the carbon absorption coefficient curves obtained from various carbon thickness. The accuracy of this method is tested by comparing the X-ray spectrum measured by the TGS with that obtained by a soft X-ray spectrometer.

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In order to investigate the effect of inclination angle on the spatial distribution of phases, experiments on gas-liquid two-phase slug flow in an inclined pipe were carried out by using the optical probe and an EKTAPRO 1000 high speed motion analyzer. It has been demonstrated that the inclination angle and the mixture velocity are important parameters to influence the distribution of void fraction for upward slug flow in the inclined pipe. At high mixture velocity, the gas phase profile is axial symmetry in the cross-section of the pipe. This is similar to that for vertical slug flow. In contrast, most of the gas phase is located near the upper pipe wall at low mixture velocity. By measuring the axial variation of void fraction along the liquid slug, it can be concluded that there is a high void fraction wake region with length of 3~4D in the front of liquid slug. In the fully developed zone of liquid slug, the peak value of the void fraction is near the upper wall.

232

The radioisotope X-ray fluorescence method was applied to studies of the provenance of the ceramics fragments originated from the Mar-Takla site in Syria. The samples were irradiated 1000s by a ¹⁰⁹Cd radioisotope source and 13 elements (Ca, Ti, Mn, Fe, Zn, Ga, As, Rb, Sr, Y, Zr, Nb, and Pb) were determined in 35 samples. The data were subjected to two multivariate statistical methods, cluster and principal components analysis (PCA). It was shown from the combination of the statistical techniques and the determination of elemental composition of the samples that 94% of the ceramic samples analyzed can be considered to be manufactured using two sources of raw materials.

233

A practical regression method of saturation exponential in pre-dose technique is proposed. The method is mainly applied for porcelain dating. To test the method, some simulated paleodoses of the imitations of ancient porcelain were used. The measured results are in good agreement with the simulated values of the paleodoses, and the average ratios of the two values by using the two ways are 1.05 and 0.99 with standard deviations (±1σ) of 19% and 15% respectively. Such errors can be accepted in porcelain dating.

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