Preparation and characterization of end-alkoxysilylated polystyrene and the grafting behaviors onto inorganic pigments. II. Utilization of 4-triethoxysilyl-α-methylstyrene

Novel polystyrene was prepared with triethoxysilyl (TES) groups at the end of the chain, and the grafting behaviors of the resulting polymer onto silica, alumina, and titania were studied. TES groups were introduced by the reaction between living polystyryl anion and 4-triethoxysilyl-α-methylstyrene (1) in THF at 195 K. The end-functional polymer was characterized by GPC, ¹H-NMR, and TLC. It was confirmed that the polymer had several units of 1 at the chain end and a fairly narrow molecular weight distribution. TES groups in the present polymer were found to be hydrolyzed with both acids and bases such as mono-n-butylphosphate (MBP) and tetrabutylammonium hydroxide (TBAH), respectively. The polymer was effectively grafted onto silica and alumina in toluene in the presence of MBP and TBAH, respectively. The amount of graft, estimated by thermogravimetry, changed with the selection of substrates and catalysts; about 2 mg/m² at the highest. The change in the amount of graft can be explained by the amount of effective acidic- or basic-hydroxyl groups on the substrate surfaces. However, titania received the largest amount of graft in the absence of catalyst. This may be because the strong acidic sites on the surface of titania act as a hydrolytic catalyst. The present polymer is expected to find wide application as a macromolecular dispersant for various types of inorganic pigments. © 1996 John Wiley & Sons, Inc.     

Starch Properties of a Waxy Mutant Line of Hull‐less Barley (Hordeum vulgare L.)

Endosperm starch isolated from an amylose‐free waxy mutant hull‐less barley line, Shikoku Hadaka 97, had an amylose content of 0.3% and higher swelling power than ordinary waxy barley cultivars/lines with amylose contents of 2.2—6.5%. A highly significant correlation was observed between amylose content and swelling power among waxy barley starches. No clear differences were detected in the chain‐length distribution profiles or thermal properties between the amylose‐free starch and ordinary waxy starch. The chain‐length distribution profile of waxy barley starch was slightly different from that of normal barley starch. Gelatinization temperatures and gelatinization enthalpy of waxy barley starch were higher than those of normal barley starch. Significant correlations were observed between amylose content and thermal properties of starch samples analyzed. Waxy barley starch stained with a concentrated iodine‐potassium iodide solution showed a ghost‐like appearance.     

0.8 MeV单能中子照射洋葱萌发种子后在根尖细胞中诱发微核的相对生物效能

通过由加速器产生的0.8 MeV单能中子和60Coγ射线照射洋葱萌发种子,观察在根尖细胞中微核诱发率,从而更好地了解中子相对生物效能(RBE)。洋葱萌发种子照射单位剂量0.8 MeV单能中子和60Coγ射线后,根尖细胞中的微核诱发率分别为111±6.7(10-2Gy-1)和3.59±0.19(10-2Gy-1)。因此,以60Coγ射线为参考辐射时,0.8 MeV单能中子在洋葱根尖细胞诱发微核的相对生物效能(RBE)值为31.0±2.5。与252Cf裂变中子的RBE比较,0.8 MeV单能中子照射在洋葱根尖细胞中诱发微核的RBE值要高。     

Systemic Delivery of Protein Nanocages Bearing CTT Peptides for Enhanced Imaging of MMP-2 Expression in Metastatic Tumor Models

Matrix metalloproteinase 2 (MMP-2) in metastatic cancer tissue, which is associated with a poor prognosis, is a potential target for tumor imaging in vivo. Here, we describe a metastatic cancer cell-targeted protein nanocage. An MMP-2-binding peptide, termed CTT peptide (CTTHWGFTLC), was conjugated to the surface of a naturally occurring heat shock protein nanocage by genetic modification. The engineered protein nanocages showed a binding affinity for MMP-2 and selective uptake in cancer cells that highly expressed MMP-2 in vitro. In near-infrared fluorescence imaging, the nanocages showed specific and significant accumulation in tumor tissue after intravenous injection in vivo. These protein nanocages conjugated with CTT peptide could be potentially applied to a noninvasive near-infrared fluorescence detection method for imaging gelatinase activity in metastatic tumors in vivo.     

The preparation of a novel Si–CNF composite as an effective anodic material for lithium–ion batteries

The suggested pyrolytic carbon (PC) coated Si-carbon nanofiber (CNF) composites can be a solution to provide higher discharge capacity and cycle-ability facilitating the 1st cycle coulombic efficiency of cheap metallic Si particles as an appropriate anodic material for Li-ion battery. The CNFs on the surface of Si particle can provide flexible space to relieve volumetric expansion during charge. Well-controlled PC coating on the surface of Si particle can improve the coherence of CNFs on the Si particle, thereby to enhance the role of CNF as all the more effective electrode material. The additional PC coating on the Si–CNF composite can accomplish the lower surface area and afford the improvement of the 1st cycle coulombic efficiency. Ingenious combinations of PC coating and CNF compositeness successfully made the novel type Si–CNF composite to achieve a remarkable discharge capacity (1115 mA h g⁻¹), an excellent cycle-ability (77% retention rate after 20th cycle), and a good 1st cycle coulombic efficiency (79%) for the effective application as an anode material.     

Dispersive XAFS Study on Cu and Mo Species in Zeolites During the Catalyst Preparation

A time-resolved energy dispersive XAFS (DXAFS) technique is applied to elucidate the local structure of catalyst precursors and active species during the preparation of catalysts. The structure of ion-exchanged copper species in ZSM-5 zeolite during temperature-programmed reduction and the structure of molybdenum carbonyl species in NaY zeolite during temperature-programmed decarbonylation were investigated by the DXAFS technique. The way of the analysis of XAFS data during the dynamic processes is also discussed. The XANES spectra were analyzed to determine the ratio of different species involved in the system as a function of temperature as well as the curve-fitting analysis of the time-resolved EXAFS. The detailed analysis of the XANES and EXAFS shed light on the structural changes during the dynamic processes. In Cu-ZSM-5, a stepwise reduction process of Cu species and the subsequent growth of Cu particles during the reduction were elucidated. In Mo–NaY, the formation of Mo subcarbonyl monomer species as an intermediate of molybdenum oxycarbide dimer species was observed. This paper demonstrates that the DXAFS technique is useful to study the chemistry of catalyst preparation and can provide vital information that cannot be obtained by other techniques.     

Anti-angiogenic effect of an insertional fusion protein of human basic fibroblast growth factor and ribonuclease-1

Human pancreatic ribonuclease-1 (RNase1) does not exhibit its cytotoxicity unless it is artificially internalized into the cytosol. Furthermore, once it encounters the cytosolic RNase inhibitor (RI), the activity of RNase1 is seriously reduced. To achieve the cellular targeting of RNase1 and the blocking of RI binding simultaneously, the basic fibroblast growth factor (bFGF) sequence was inserted into RNase1 at the RI binding site using a gene fusion technique. The effect of this fusion protein, CL-RFN89, on the angiogenesis, which was accelerated by FGF-FGF receptor interaction, was investigated. It was shown by using fluorescein-labeled CL-RFN89, that the binding to human umbilical vein endothelial cells (HUVECs) was dependent on the existence of the FGF receptors. In addition, CL-RFN89 inhibited the cellular growth of HUVECs in vitro and also inhibited the tube formation, using a three-dimensional tube formation assay. Furthermore, this fusion protein was shown to prevent in vivo tumor cell-induced angiogenesis, using the mouse dorsal air sac assay. These results demonstrated that CL-RFN89 inhibits angiogenesis in vitro and in vivo and that it can be expected to be a potent antiangiogenic agent.     

Ultrahigh resolution soft x-ray emission spectrometer at BL07LSU in SPring-8

An extremely high resolution flat field type slit less soft x-ray emission spectrometer has been designed and constructed for the long undulator beamline BL07LSU in SPring-8. By optimizing the ruling parameters of two cylindrical gratings, a high energy resolution ΔE < 100 meV and/or an E∕ΔE ~ 10 000 are expected for the energy range of 350 eV - 750 eV taking into account the broadening by the spatial resolution (25 μm) of a CCD detector. A coma-free operation mode proposed by Strocov et al., is also applied to eliminate both defocus and coma aberrations. The spectrometer demonstrated experimentally that E/ΔE = 10 050 and 8046 for N 1s (402.1 eV) and Mn 2p (641.8 eV) edges, respectively.     

SMA粒子和短纤维填充的复合材料的力学特性

形状记忆合金（SMAs）由于其可塑的记忆效果,短期弹性、高阻抗容量和其他特性,因而具有感知和激励的功能。利用SMAs独一无二的特性,结合其他材料可用来制造出智能化或灵敏的合成材料。研究利用镍钛合金短纤维和颗粒制造的环氧合成材料的力学性能。由于加入了SMA,SMA／环氧合成材料具有更强的抗弯抗剪能力。特别在高温下,存储系数随着SMA显著增加。试验结果表明,SMA每增加3．5％,存储系数将有显著的增加,影响量级为环氧的6倍。当SMA相变接近120°时,存储系数增大到了最大值。SMA／ER3合成材料的损失因素随着SMA的增加而增加。基于Halpin-Tsai理论,具有SMA的薄层可以代表整个材料动力性能。相对于其他试验材料,在现有模型上得到的结论可以合理地预测这些动力响应。     

A novel method of examining carbonaceous deposits on spent catalyst surfaces

Xenon ion-bombardment used in conjunction with Auger electron spectroscopy was able to discriminate two types of carbonaceous materials accumulated on the surfaces of iron oxide and rhenium/iron-oxide catalysts spent for CO hydrogenation at 250°C and 2.1 MPa. One of the carbonaceous materials was easily eliminated from the surfaces by ion bombardment or by heat-treatment in vacuo at 150°C. On iron oxide only this “soft” carbonaceous material was present. On rhenium/iron oxide, bombardment-resistant “hard” carbonaceous material was also found. The presence of this hard carbonaceous material had little effect on the level of CO hydrogenation activity or the deactivation behavior of this catalytic system.