Vol.14,

The weak pre-edge features in the Mn K-edge X-ray absorption near-edge structure (XANES) spectrum of manganese monoxide (MnO) were investigated by comparing experimental data with dipolar and quadrupolar cross-section calculations in the framework of multiple-scattering theory. We assign the first pre-edge feature to a direct quadrupolar transition from 1s core state to 3d molecular orbitals of the central atom, e.g., the lowest in energy, due to the more effective attraction of the core hole. The second peak in this region arises unambiguously from the hybridization between p-orbitals of the central atom with higher-shell metal octahedral orbitals.

431

In this paper, analysis of the beam orbit stability and conceptual study of the dynamic orbit feedback in the SSRF storage ring are presented. It is shown that beam orbit position movement at the photon source points is smaller than the orbit stability requirements in horizontal plane, but exceeds the orbit stability requirements in vertical plane. A dynamic global orbit feedback system, which consists of 38 high-bandwidth air-coil correctors and 40 high-precise BPMs, is proposed to suppress the vertical beam orbit position movement. Numerical simulations show that this dynamic orbit feedback system can stabilize the vertical beam orbit position movement in the frequency range up to 100 Hz.

510

Germination capacity of alfalfa seeds under low energy N⁺ implantation manifests oscillations going down with dose strength. From analyzing alfalfa genome DNA under low energy N⁺ implantation by RAPD (Random Amplified Polymorphous DNA), it is recommended that 30 polymorphic DNA fragments be amplified with 8 primers in total 100 primers, and fluorescence intensity of the identical DNA fragments amplified by RAPD is different between CK and treatments. Number of different polymorphic DNA fragments between treatment and CK via N⁺ implantation manifests going up with dose strength.

501

Al precipitates as well as cavities (or open-volume defects) are known for their ability to getter impurities within Si. In order to compare their relative gettering strength we produced both Al precipitates and cavities at different depths within one Si wafer. This was done by H⁺ and Al⁺ implantation with different energies and subsequent annealing process, resulting in Al-Si alloy and cavities at depth of 300 nm and 800 nm, respectively. Cu was then implanted with an energy of 70 keV to a fluence of 1×10¹⁴/cm². The Cu implanted samples were annealed at temperature from 700℃ to 1200℃. It was found that Cu impurities were gettered primarily by the precipitated Al layer rather than by cavities at the temperature of 700~1000℃, while gettering of Cu occured in both regions at the temperature of 1200℃. The secondary ion mass spectrometry and transmission electron microscopy analyses were used to reveal the interaction between Cu impurities and defects at different trap sites.

472

The extraction of uranium (VI) from nitric acid solution with N-octanoyl-2-methylpiperidine (OMPPD) in eight diluents and the dependence of distribution ratio on temperature and concentrations of both aqueous nitric acid and OMPPD were investigated. The interaction among OMPPD, the extracted species and diluent has been discussed. The experiments show that the extraction ability of OMPPD decreases gradually for eight diluents in the following order: benzene, toluene, n-octane, sulfonated kerosene, cyclohexane, carbon tetrachloride, 1,2-dichloroethene and chloroform. It cannot be interpreted only on the basis of polarity of diluents.

281

The comet assay (single cell gel electrophoresis assay) was used to evaluate the radiotoxicity of Auger electron emitters in the human osteosarcoma cell line (HOS-8603). After internal exposure to ⁶⁷Ga-EDTMP, the sarcoma cell has been injured severely. The comet length was longer along with the increase of dose, the appearance of comet tail was different from that with respect to the ⁶⁰Co γ-ray irradiation. DNA damage of cell was mainly due to the radiation effect of Auger electrons. The ⁶⁷Ga may be a therapeutic radionuclide with good prospect for tumor treatment and palliation of bone pain induced by metastasis.

495

355

Nuclear factor NF-κB is believed to play an important role in regulating the production of matrix metalloproteinases (MMPs), which induce atherosclerosis, restenosis and plaque rupture. We incubated rabbit vascular smooth muscle cells(RVSMCs)with 5 μmol/L lovastatin in the presence of IL-1-α and PDGF_BB (20 μg/L, respectively) to study whether lovastatin inhibited NF-κB binding activity induced by IL-1 and PDGF. The NF-κB activity was detected by electrophoretic mobility shift assay (EMSA); MMP-1 and MMP-3 were measured by western blotting; and MMP-9 was detected by zymography. The result showed that lovastatin strongly reduced NF-κB activity upregulated by IL-1 combined with PDGF, and lovastatin also dose-dependently inhibited the expression of MMP-1, -3 and -9 induced by IL-1 and PDGF. It suggested that the beneficial effects of statins may extend to mechanisms beyond cholesterol reduction.

272

The Alpha Magnetic Spectrometer experiment is realized in two phases. A precursor flight (STS-91) with a reduced experimental configuration (AMS01) has successfully flown on space shuttle Discovery in June 1998. The final version (AMS02) will be installed on the International Space Station (ISS) as an independent module in early 2006 for an operational period of three years. The main scientific objectives of AMS02 include the searches for the antimatter and dark matter in cosmic rays. In this work we will discuss the experimental details as well as the improved physics capabilities of AMS02 on ISS.

332

439

Owing to the high oxygen-respiration in the brain of mammals, oxidative damage to prion protein has been suggested to be an additional factor. A large body of intriguing features of scrapie and prion diseases have provided multiple lines of indirect chemistry evidence, suggesting that the infectious agents may be putative forms of sequence-specific prion radicals (SSPR) and /or their immediate precursors in the transmissible spongiform encephalopathies (TSE). Here a molecular mechanism corresponding to the self-replication of scrapie protein mediated by prion free-radical processes, consonant with "protein-only" hypotheses is proposed. This new theory may not only aid our understanding of the occurrence of prions, but also provides new insight into the possible chemistry principles underlying the neurodegenerative disorders. It is anticipated that future studies based on this suggestion and chemistry principles of genetic diseases may allow us to determine an effective approach to stop mad cow disease and its human version, new variant of Creutzfeldt-Jakob disease (v CJD).

302

Extremely rapid evaporation could occur when high-temperature particles contact with low-temperature liquid. This kind of phenomenon is associated with the engineering safety and the problems in high-transient multi-phase fluid and heat transfer. The aim of our study was to design and build an observable experiment facility. The first series of experiments were performed by pouring one or six high-temperature particles into a low saturated temperature liquid pool. The particle's falling-down speed was recorded by a high-speed camera, thus we can find the special resistant feature of the moving high-temperature particles, which is induced by the high-speed evaporation surrounding the particles. The study has experimentally verified the theory of evaporation drag model.

618

Radial distribution of vapor local parameters, including local void fraction, interfacial velocity, bubble size, bubble frequency and interfacial area concentration, are investigated through the measurement in an upward boiling tube using dual-sensor optical probe. In addition, a new local parameter— "local bubble number concentration" is developed on the basis of bubble frequency. The analysis shows that this parameter can reflect bubble number density in space, and has clear physical meaning.

301