Vol.9,

The Shanghai FEL User Facility (SFEL) for interdisciplinary studies is based on a rf linear accelerator. The prime goal of SFEL is to provide a broadly tunable laser beam from near-IR to far-IR with tens of MW at peak power. A linear accelerator will operate in three modes: ~ 3 MeV mode, 20 ~ 30 MeV mode and 40 ~ 50 MeV mode. In 20 ~ 30 MeV mode, the accelerator consists of a ns grid gun driven at 476 MHz, a 476 MHz subharmonie buncher, a 2856 MHz T-W type of buncher with high field gradients, and a SLAC type linac.

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A rotating range modulator was designed and manufactured, which is applied to extend Bragg peak of heavy ion beam. Bragg curves of 75MeV/u ¹⁶O and 75MeV/u ¹²C ion beams through this range modulator were measured respectively and two evident spread-out Bragg peaks corresponding to the modulated beams above are shown. In addition, inactivation effect of the modulated 75MeV/u ¹⁶O ion beam at nine different penetration depths on melanoma cells (B₁₆) was measured. Results indicate that lethal effects at the spread-out Bragg peak region are larger than at the plateau of the particle beam entrance.

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The behavior of materials heated by X rays to high energy density state is a very interesting and active research field for application in inertial fusion, astrophysics and so on. Some new experiments on X-ray-ablated C₈H₈ samples were designed and performed on Xingguang one beam frequency-tripled Nd:glass laser facility. The ablation velocity and the mass absorption coefficient of C₈H₈ foam, and the self-cmission spectrum of C₈H₈ foil were experimentally obtained. The experiments and results are briefly described.

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The synthesis and biodistribution were discribed for ^99mTc labelled fatty acid, p-[(N,N'-di-carboxymethyl) aminomethyl carboxyamino]-phenylpentadecanoic acid (CACPPA). ^99mTc-CACPPA was prepared by the reduction of Na^99mTcO₄ with stannous chloride in aqueous solution at pH 8.5〜9.5, the labelling yield and chemical purity were over 90% determined by TLC and HPLC. Biodistribution of ^99mTc-CACPPA in mice demonstrated that the highest myocardial uptake of ^99mTc-CACPPA was 18.17±2.67% ID/g. When blood disappearance of ^99mTc-CACPPA was analysed with a biexponential model, an initial half time of 1.11 min and a late half time of 20.08 min were obtained. ^99mTc-CACPPA exhibited high binding to HSA in vitro, and partition coefficients were 10.98 and 11.45 at pH7.00 and pH7.40, respectively.

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Radioimmunoassay (RIA) for pepsinogens Ⅰ and II (PG Ⅰ and Ⅱ) in serum is developed by using the purified PG Ⅰ and Ⅱ from human gastric mucosa. The assay range was 8~256μg/L for PG Ⅰ and 2~64μg/L for PG Ⅱ, the sensitivity was 1.3 and 0.6µg/L, respec-tively. The reproducibilities of PG Ⅰ-RIA (106.9%) and PG Ⅱ-RIA (106.7%) are quite well. The within-and between-assay coefficient of variation (CV) of each RIA was 5.1% and 6.3% for PG Ⅰ, 7.2% and 8.9% for PG Ⅱ. The serum PG Ⅰ level in healthy volunteer was 60.41±14.98µg/L (mean±SD), significantly higher than the serum PG Ⅱ level which was 20.70±9.64µg/L. There-fore, the PG Ⅰ-RIA and PG Ⅱ-RIA are useful tools in studying the relation between serum pepsinogen levels and various peptic disorders.

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Serum heat-stable alkaline phosphatase (HSAP) level in 649 cases of normal pregnancy and 164 cases of high-risk pregnancy is measured by radioimmunoassay (RIA). The results indicate that the HSAP level in normal pregnancy increased proportionally with gestation weeks (τ=0.9843). In 33 cases of pregnancy indnced hypertension and 21 cases of intrauterine fetal growth retardation, the HSAP level is significantly low. In 7 cases of neonatal asphyxia and 26 cases of fetal distress, the HSAP level in the mother's serum is also low. In 53 cases of intrahepatic cholestasis of pregnancy, the HSAP level is similar to those of normal pregnancy. This study illustrates that HSAP RIA can play an important role in the evaluation of placental function and fetal prognosis for cases of high-risk pregnancy.

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The interfacial wave patterns and their transition charaeteristics in gas-liquid two-phase flow through rectangular and circular horizontal conduits are investigated. The interfacial waves were traced and recorded by using conductance probes. With the experimental observation and the analysis, some kinds of different interfacial waves were distinguished and defined, and then the interfacial wave patterns were given, which were compared with previous results. The interfacial wave transition mechanism between eaeh interfacial wave pattern was discussed and a set of transition equations were presented to predict the interfacial wave pattern transitions. The predictive results are in good agreement with the experimental data.

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The testes of the B6C3F1 hybrid strain mice were irradiated with 0.05 Gy of ¹⁶O⁸⁺ ion/⁶⁰Co γ-ray as the pre-exposure dose, and were then irradiated with 2 Gy of ¹⁶O⁸⁺ ion/⁶⁰Co γ-ray as challenging irradiation dose at 4h after pre-exposure. The results show that irradiation of mouse testes with 2 Gy of ¹⁶O⁸⁺ ion or ⁶⁰Co γ-ray significantly diminished mouse body mass, testis mass and serum testosterone. However, pre-exposure with a low-dose (0.05 Gy) significantly reduces this kind of effect. The relative biological effectiveness of ¹⁶O⁸⁺ ion was calculated with respect to ⁶⁰Co γ-ray for the induction of reduction in body mass, testis mass and serum testosterone to be 1.71, 1.81 and 1.42, respectively.

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The apoptosis in human acute lymphoblastic leukemia cell line Molt-4 cell and macrophage cell line Ana-1 cell are studied after internal irradiation with enriched uranium ²³⁵U. The cumulative absorption dose of ²³⁵U in cultural cells through different periods are estimated. The fluorescence microscopic observations indicate that Molt-4 and Ana-1 immune cells internally irradiated by ²³⁵U displayed significant chromatin fragmentation and marked pyknosis in immune cells nuclei, as well as DNA chain fragmentation and apoptotic bodies formation. It should be noted that DNA chain fragmentation induced by ²³⁵U may be inhibited statistically by IL-2 (interleukin-2) or IL-6 treatment.

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Accumulation contents and concentration factors (CF) for ⁵⁴Mn, ⁶⁰Co, ⁵⁸Co, ¹²⁴Sb occurring simultaneously in aquatic organisms were determined. The results show that CF correlates to nuclides, the species of organisms, the culture time and the specific activity (SA) of nuclides in water, and their relationship can be expressed by regression equations. Among shrimp, snail, ophiocephalus argus and carassius auratus, the shrimp has the highest CF particularly for ⁵⁴Mn, the CF reaches 291.5, the ophiocephalus argus has the lowest. The distribution of nuclides in fish has the magnitude order: gill>viscera>epidermis>bone>flesh.

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³²P-labelled KH₂PO₄ with or without unlabelled ryegrass and ³²P-labelled ryegrass with unlabelled KH₂PO₄ were respectively applied to red soil, and ryegrass was grown in the fertilized soil and harvested one month after sowing and then the radioactivities and total P content in ryegrass were measured. Results show that addition of organic matter to red soil can significantly stimulate the uptake of P by ryegrass seedlings from inorganic P applied to red soil; absorption of P from inorganic source is much greater than that from organic source; at the same application level of P, larger proportion of P derived from labelled inorganic phosphate was distributed in shoots than that from the labelled ryegrass.

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By using ¹⁵N tracer method, transformation of organic N, which was newly added to red soil treated with different cultural practices, was studied under the laboratory incubation condition. The experimental results showed that the transformation of N from newly added organic matter and soil native pool during incubation was influenced by cultural practice treatment before incubation. Fallow was favorable to the mineralization of newly added organic N and soil N compared with the planting wheat treatment. Planting wheat greatly increased the loss of soil N. Application of fertilizers stimulated the mineralization of newly added organic N and application of organic matter reduced the mineralization, but stimulated microbial transformation of newly added organic N.

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An investigation on the dynamics of transformation of P from ³²P-labelled ryegrass in red soils was conducted in laboratory. The results showed that the rapid increase in flush ³²P related with biomass P was accompanied with the decrease in extractable ³²P on the first 3d of incubation in both sandy and clayey soils, and afterwards, it displayed great fluctuation in sandy soil, but had little fluctuation in clayey soil during 3〜20d of incubation. At the later stage of incubation, the increase in extractable ³²P was accompanied with decrease in flush ³²P. The opposite changes in content of extractable ³²P and flush ³²P suggested transformation of ryegrass P was closely related to its utilization and its release from microorganisms in red soils. It can be concluded that addition of organic matter accelerated the release of soil native P according to the changes in the extractable soil P during incubation.

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