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161.
162.
Discovery of deep-level foreland thrust-fold structures in Taihang Mt. and its implication for early tectonic evolution of North China 总被引:5,自引:0,他引:5
Delineation and correlation of Dragon Spring Shear Zone with its deep-level structures at foreland have been studied by field work. This paper reports our new findings of thrust-fold structures within Taihang Neoarchean basement, which include flat thrusts,large-scale recumbent folds, subhorizontal foliation patterns, etc. It reveals that early tectonic evolution of North China clearly involves the horizontal contraction on a large scale, comparable to those of foreland of classical collisional orogenic belts. The vertical variation of structural patterns with foreland fold-thrust belt from shallow to deep levels has been documented for Taihang Mt. by structural correlation,which is associated with tectonic transposition and imbrication of basement complex with supracrustal sequences in the Neoarchean. 相似文献
163.
Restoration of photoreceptor ultrastructure and function in retinal degeneration slow mice by gene therapy 总被引:17,自引:0,他引:17
Ali RR Sarra GM Stephens C Alwis MD Bainbridge JW Munro PM Fauser S Reichel MB Kinnon C Hunt DM Bhattacharya SS Thrasher AJ 《Nature genetics》2000,25(3):306-310
The gene Prph2 encodes a photoreceptor-specific membrane glycoprotein, peripherin-2 (also known as peripherin/rds), which is inserted into the rims of photoreceptor outer segment discs in a complex with rom-1 (ref. 2). The complex is necessary for the stabilization of the discs, which are renewed constantly throughout life, and which contain the visual pigments necessary for photon capture. Mutations in Prph2 have been shown to result in a variety of photoreceptor dystrophies, including autosomal dominant retinitis pigmentosa and macular dystrophy. A common feature of these diseases is the loss of photoreceptor function, also seen in the retinal degeneration slow (rds or Prph2 Rd2/Rd2) mouse, which is homozygous for a null mutation in Prph2. It is characterized by a complete failure to develop photoreceptor discs and outer segments, downregulation of rhodopsin and apoptotic loss of photoreceptor cells. The electroretinograms (ERGs) of Prph2Rd2/Rd2 mice have greatly diminished a-wave and b-wave amplitudes, which decline to virtually undetectable concentrations by two months. Subretinal injection of recombinant adeno-associated virus (AAV) encoding a Prph2 transgene results in stable generation of outer segment structures and formation of new stacks of discs containing both perpherin-2 and rhodopsin, which in many cases are morphologically similar to normal outer segments. Moreover, the re-establishment of the structural integrity of the photoreceptor layer also results in electrophysiological correction. These studies demonstrate for the first time that a complex ultrastructural cell defect can be corrected both morphologically and functionally by in vivo gene transfer. 相似文献
164.
Mutations in SPINK5, encoding a serine protease inhibitor, cause Netherton syndrome 总被引:23,自引:0,他引:23
Chavanas S Bodemer C Rochat A Hamel-Teillac D Ali M Irvine AD Bonafé JL Wilkinson J Taïeb A Barrandon Y Harper JI de Prost Y Hovnanian A 《Nature genetics》2000,25(2):141-142
We describe here eleven different mutations in SPINK5, encoding the serine protease inhibitor LEKTI, in 13 families with Netherton syndrome (NS, MIM256500). Most of these mutations predict premature termination codons. These results disclose a critical role of SPINK5 in epidermal barrier function and immunity, and suggest a new pathway for high serum IgE levels and atopic manifestations. 相似文献
165.
In this paper we examine the role of top management in relation to the diversified operations of a company and the meaning of “strategic planning” for these entities. We briefly examine two general approaches to generation of growth: conglomeration (portfolio management) and synergistic growth. We argue that the second is preferable. We then challenge the universally popluar notion that growth is the appropriate objective for a business entity. We propose the concept of “development” as a better alternative. We offer the case of Armco's Latin American Division (known as ALAD) as an illustration of the kind of thinking that emerges when development is taken as the corporate objective. We present a five-phase strategy that combines the notions of synergistic growth and corporate development in a systemic framework. 相似文献
166.
Effect of Al2O3 and Y2O3 on the corrosion behavior of ZrO2-benzotriazole nanostructured coatings applied on AA2024 via a sol-gel method 下载免费PDF全文
zirconia-based nanostructured coatings were deposited on AA2024 to improve the corrosion resistance properties. Three different nanostructured coatings, namely, zirconia-benzotriazole, zirconia-alumina-benzotriazole, and zirconia-yttria-benzotriazole, were applied on AA2024 via a sol-gel method using the dip-coating technique. Next, the coatings were annealed at 150℃ after each dipping period. The phases and morphologies of the coatings were investigated using grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). The corrosion properties were evaluated using electrochemical methods, including polarization and electrochemical impedance techniques in 3.5wt% NaCl solution. The obtained results confirm the formation of homogeneous and crack free zirconia-benzotriazole-based nanostructured coatings. The average roughness values for zirconia-benzotriazole, zirconia-alumina-benzotriazole, and zirconia-yttria-benzotriazole nanostructured coatings were 30, 8, and 6 nm, respectively. The presence of alumina as a stabilizer on zirconia coating was found to have a beneficial impact on the stability of the corrosion resistance for different immersion times. In fact, the addition of alumina resulted in the dominance of the healing behavior in competition with the corrosion process of zirconia-benzotriazole nanostructured coating. 相似文献
167.
Quantification of digoxin by enzyme immunoassay: synthesis of a maleimide derivative of digoxigenin succinate for enzyme coupling 总被引:1,自引:0,他引:1
Summary We synthesized the m-maleimidobenzoyl derivative of digoxigenin-3-0-succinate (through a p-phenylenediamine bridge) as a hapten derivative directed towards coupling to sulfhydryl groups of -galactosidase. Prepared enzyme conjugate had about 97% of the enzyme labeled with the hapten derivative while retaining full enzyme activity. The enzyme immunoassay for digoxin we prepared showed a maximum sensitivity of 30 pg per assay (c.v.=3%) with minimal cross-reaction with digotoxin (3.8%). Our method for hapten conjugation to -galactosidase is highly efficient and is simple and easily replicated. 相似文献
168.
利用临界点理论和广义Nehari流形方法,考虑一类周期离散非线性Schrdinger系统,得到了该类系统无穷多个几何不同解的存在性,并用该方法得到了单个周期离散Schrdinger方程解的多重性. 相似文献
169.
壬二酸的性质、合成和应用 总被引:3,自引:0,他引:3
本综述了壬二酸的性质,用途及合成方法。介绍了国内外采用臭氧氧化法合成壬二酸的研究进展。对臭氧氧化法合成壬二酸的反应机理,合成工艺做了较为系统的总结并对臭氧氧化法在精细化工中的应用做了展望:臭氧氧化法作为一种清洁工艺在油脂深加工和精细化工产品的开发方面大有可为。 相似文献
170.
Mokhtar Rejili Dalel Telahigue Belgacem Lachihe Abdessalem Mrabet Ali Ferchichi 《自然科学进展(英文版)》2008,18(9):1095-1106
The perennial Medicago sativa cv. Gabès is widely grown on saline soils in Tunisian oases. Morphological and physiological analyses of two populations (Mareth and Gannouch) were conducted in order to study the effect of salinity and gamma radiation (350 Gy) interaction on two populations of this species. It has been shown that the two irradiated populations of Medicago sativa are fairly tolerant to salt at growth phase compared to the non-irradiated. Exposure to gamma irradiation (350 Gy), alone or in combination with salt stress, increased significantly (p<0.001) shoot number, stem height and chlorophyll b pigment especially for the Gannouch population, while no change occurred for the Mareth population. The presence of salt to 9g/l affected significantly the root biomass and induced a reduction of shoot development of both control and irradiated alfalfa populations. For all treatments, plants of two populations remained able to produce and to allocate dry matter to the different organs. The survey of Na+ / K+ ratio showed that the growth of the aerial organs of two non-irradiated populations was at least determined by a selectivity in favour of the K+ ions (r2 = 0.97 and r2 = 0.59 for Mareth and Gannouch irradiated populations, respectively). However, the rather weak correlation detected for the irradiated populations, particularly for the irradiated Gannouch, seems to be the consequence of the effect of irradiation that improved potassium availability, essential element for growth and development. Results also showed that the two irradiated populations, especially the Mareth, accumulated Na+ ions in its photosynthetic organs. This accumulation was associated with an improvement of foliar water content at a level of salinity arrounding 5g/l. Such a mechanism reflects probably an inclusive behaviour of the plants and a good aptitude to use the dominant ions (Na+) for the osmotic adjustment. However, the non-irradiated populations are unable to adjust their internal osmotic potential. Consequently, irradiated plants have probably adapted to the osmotic stress by either closing their stomata or increasing the osmotic pressure of the leaf cells. 相似文献