Immune responses to Ro60 and its peptides in mice. I. The nature of the immunogen and endogenous autoantigen determine the specificities of the induced autoantibodies

Two fatty acid hydroperoxide lyases (HPO lyase I and II) were purified to apparent homogeneity from etiolated hypocotyls of sunflower (Helianthus annuus L.) by a combination of ion-exchange, hydrophobic interaction, and gel filtration chromatography. The two HPO lyases were separated during the hydrophobic interaction chromatography step, with HPO lyase I more hydrophilic than HPO lyase II. The estimated M(r) of both native HPO lyases was determined by gel filtration to be 200,000 and SDS-PAGE in the presence of 100 mM dithiothreitol showed that the enzyme was composed of a single 53 kDa peptide, suggesting that the enzyme exists as a tetramer in vivo. HPO lyase was also abundant in the cotyledons and green leaves. HPO lyases I and II from hypocotyl metabolized 13-hydroperoxylinoleic acid and 13-hydroperoxylinolenic acid to the same extent, but the green leaf enzyme was more than ten-fold more active with 13-hydroperoxylinolenic acid than 13-hydroperoxylinoleic acid. A difference spectrum between CO-bound and CO-unbound dithionite-reduced HPO lyase I showed an absorbance maximum at 452 nm, indicating that it was a cytochrome P450-type enzyme. The activities of HPO lyase I and II were significantly inhibited by nordihydroguaiaretic acid, sulfhydryl reagents, and piperonylbutoxide, which is a cytochrome P450 inhibitor.     

防恐操作平台:美国对水坝人为破坏的防护策略

美国在遭受“911”恐怖事件袭击后,正发起“反恐全民准备运动”。为避免水坝保安措施的不足及人为的疏失,美国政府开始推动“水坝安全之破坏风险评估”。2002年12月美国总统签署了“水坝安全和保安法案”,正式立法防范水坝人为破坏,确保水坝和公众安全。     

Cracking behavior of evaporated amorphous silicon films

The residual stress in amorphous silicon films deposited by evaporation is investigated with different substrate temperatures. The stress measured from all the films studied in this paper is tensile. The level of stress decreases from 580 MPa to 120 MPa with increasing substrate temperature from 60 °C to 350 °C. When the film becomes thicker, strain increases and cracks are formed for stress relaxation. 10 µm thick amorphous Si films are deposited at 350 °C without cracks. This cracking behavior is theoretically studied and confirmed by experiment.     

A model for nucleation and growth of single wall carbon nanotubes via the HiPcO process: a catalyst concentration study

Using the High Pressure carbon monoxide (HiPco) reactor we conducted an experiment on the effects of changing the catalyst concentration. With each catalyst concentration tested the resulting raw HiPco material was characterized for average SWNT lengths, SWNT diameters, residual iron particle size, and large fullerene content. We were able to determine trends in each of these characteristics as the catalyst concentration was changed. As the catalyst concentration was decreased SWNT lengths increased, SWNT diameters increased, the residual iron particle size increased, and the large fullerene content decreased. From these trends we have developed a Competitive Growth model for nucleation and growth of SWNTs via the HiPco process.     

Potassium fertilization in relation to plant water potential of wheat

The water potential of wheat plants increased during the mid-day noon, probably as an adaptation; the rise was greater with less frequent irrigation and was increased by KCl application.     

劳伦斯·哈普林景观实践中的生态智慧及当代启示

从劳伦斯·哈普林（Lawrence HALPRIN）人生经历和实践历程出发,阐述了其生态智慧的来源,并通过对其设计作品过程的解读,梳理、总结出其景观实践中体现出的生态智慧。从结合自然的生态方法与以人为本的生态哲学两方面详述了哈普林在景观实践中体现出的超前的场地意识、科学的调套分析和将自然引八城市的理念;并介绍了生态谱记概念、面向过程和集体创作的RSVP方法．最后讨论了哈普林生态智慧对当代的启示体现在对场地的敏锐观察、科学方法与创新思维自勺统一以及多学科协作的群体智慧。     

Effect of Thermal Annealing on Carbon in In-situ Phosphorous-Doped Si1-xCx films

The effect of thermal heat treatment on carbon in in-situ phosphorous-doped silicon-carbon is studied as a function of annealing temperature and type. Films of 0 to 2% carbon were deposited using cyclic chemical vapor deposition at reduced pressures. Secondary ion-mass spectroscopy and high-resolution X-ray diffraction were employed to extract the total and substitutional carbon concentration in samples with phosphorous levels of mid-10²⁰ cm^-3. It was found that millisecond laser annealing drastically improves substitutionality while high thermal budget treatments (furnace, rapid-thermal, or spike annealing) resulted in an almost complete loss of substitutional carbon, independent of preceding or subsequent laser heat treatments.