Size distribution of heavy mineral grains in some modern Nile Delta coastal sands, Egypt

This study includes determination and discussion of the texture and heavy mineral compositions of some modem Nile Delta coastal sands (river, coastal dune, beach-face, and nearshore marine) in order to delineate the process and factors that regulate the size distribution of heavy mineral grains comprising these coastal sands. Textural analysis of unseparated bulk samples indicate that the examined four types of sands differ in their mean grain sizes and degree of sorting. However, analysis of size distribution curves of 10 heavy mineral species or group of species in the four environments having the same general shape and nearly similar in that general order of arrangement. However, these curves vary both in median sizes and sorting. The size distribution of a heavy mineral in the Nile Delta coastal sands appear to depend on: (1) range of grain size fractions in each sample, (2) relative availability of heavy mineral in each size grade of the sample, (3) specific gravity of minerals comprising these sands, and (4) some other unknown factor or factors. Results of size measurement of heavy minerals indicated that increasing specific gravity is accompanied by increasing fineness of the heavy minerals. This study may be useful in search for marine placers and understanding the processes of grain-sorting on the sea beaches.

Flux line lattice structure and behavior in antiphase boundary free vicinal YBa2Cu3O7-delta thin films

Field angle dependent critical current, magneto-optical microscopy and high resolution electron microscopy studies have been performed on YBa2Cu3O7-delta thin films grown on miscut substrates. High resolution electron microscopy images show that the films studied exhibited clean epitaxial growth with a low density of antiphase boundaries and stacking faults. Any antiphase boundaries (APBs) formed near the film substrate interface rapidly healed rather than extending through the thickness of the film. Unlike vicinal films grown on annealed substrates, which contain a high density of antiphase boundaries, magneto-optical imaging showed no filamentary flux penetration in the films studied. The flux penetration is, however, asymmetric. This is associated with intrinsic pinning of flux strings by the tilted a-b planes and the dependence of the pinning force on the angle between the local field and the a-b planes. Field angle dependent critical current measurements exhibited the striking vortex channeling effect previously reported in vicinal films. By combining the results of three complementary characterization techniques it is shown that extended APB free films exhibit markedly different critical current behavior compared to APB rich films. This is attributed to the role of APB sites as strong pinning centers for Josephson string vortices between the a-b planes. (C) 2003 American Institute of Physics.

中国9种嗜子宫线虫系统发育的初步研究

为了探讨鱼类寄生嗜子宫线虫的系统发育关系,测定了8种嗜子宫线虫的ITS rDNA(核糖体转录内间隔区核 糖核酸)序列和9种嗜子宫线虫的18S rDNA(小亚基核糖体核糖核酸)部分序列,并构建了18S rDNA序列的系统发 育树。在比较和分析ITS rDNA和18S rDNA两种分子标记对嗜子宫科线虫系统发育适用性的基础上,分析了嗜子 宫线虫的系统发育关系。结果表明:中国嗜子宫线虫是单系起源;黄颡鱼似嗜子宫线虫、赣州似嗜子宫线虫和棍头 嗜子宫线虫亲缘关系非常接近,可能是较晚形成的种;似嗜子宫线虫属可能应该被

Magnetocaloric effect and magnetic properties of Tb0.9 Sn0.1 MnO3

The magnetocaloric effect in magnetic materials is of great interest nowadays. In this article we present an investigation about the magnetic properties near the magnetic transition in a polycrystalline sample of a manganite Tb0.9 Sn0.1 MnO3. Particularly, we are interested in describing the nature of the magnetic interactions and the magnetocaloric effect in this compound. The temperature dependence of the magnetization was measured to determine the characteristics of the magnetic transition and the magnetic entropy change was calculated from magnetization curves at different temperatures. The magnetic solid is paramagnetic at high temperatures. We observe a dominant antiferromagnetic interaction below Tn =38 K for low applied magnetic fields; the presence of Sn doping in this compound decreases the Ńel temperature of the pure TbMnO3 system. A drastic increase in the magnetization as a function of temperature near the magnetic transition suggests a strong magnetocaloric effect. We found a large magnetic entropy change Δ SM (T) of about -4 J/kg K at H=3 T. We believe that the magnetic entropy change is associated with the magnetic transition and we interpret it as due to the coupling between the magnetic field and the spin ordering. This relatively large value and broad temperature interval (about 35 K) of the magnetocaloric effect make the present compound a promising candidate for magnetic refrigerators at low temperatures. © 2007 American Institute of Physics.

中国鲤科鱼类染色体组型的研究——Ⅸ.鳊亚科9种鱼和鲴亚科1种鱼的染色体组型

<正> 我们曾报道过分布于湖北省的鳊、鲴亚科鱼类的核型。本文继续报道采自四川和广东省的鳊、鲴亚科另10种鱼的核型考察结果。材料和方法四川半(歺又鱼)由于采集困难,仅分析了一尾雄鱼。其余9种鱼均分析了3—5尾,包括雌雄两种性别(表1)。染色体标本的制备采用体外短期培养肾细胞制片法(采自四川的鱼),或肾细胞直接制片法(采自广东的鱼)。根据我们实验室以前的工作,两种方法的核型分析结果基本上一致。每种鱼计数60—170个细胞确定其2n数。染色体分组按Levan氏的标准,核型分析方法和臂数计算均同以前的报道。核型图

Demonstration of multi-casting in a 1 × 9 LCOS wavelength selective switch

A multi-functional 1 × 9 wavelength selective switch based on liquid crystal on silicon (LCOS) spatial light modulator technology and anamorphic optics was tested at a channel spacing of 100 and 200 GHz, including dynamic data measurements on both single beam deflection and multi-casting to two ports. The multi-casting holograms were optimized using a modified Gerchberg-Saxton routine to design the core hologram, followed by a simulated annealing routine to reduce crosstalk at non-switched ports. The effect of clamping the magnitude of phase changes between neighboring pixels during optimization was investigated, with experimental results for multi-casting to two ports resulting in a signal insertion loss of-7.6 dB normalized to single port deflection, a uniformity of ±0.6%, and a worst case crosstalk of-19.4 dB, which can all be improved further by using a better anti-reflection coating on the LCOS SLM coverplate and other measures. © 2013 IEEE.

Molecular cloning and characterization of common carp (Cyprinus carpio L.) TCR gamma and CD3 gamma/delta chains

Partial cDNA sequences of TCR gamma and CD3 gamma/delta were isolated from the thymus of common carp (Cyprinus carpio L.) by the method of suppression subtractive hybridization (SSH). Subsequently the full length cDNAs of carp TCR gamma and CD3 gamma/delta were obtained by means of 3' RACE and 5' RACE, respectively. The full length of carp TCR gamma chain is 1368 bp and encodes 326 amino acids including a signal peptide region of 19 amino acids and a transmembrane region of 23 amino acids at the C-terminal region from aa 291 to 313. The V region of carp TCR gamma contains 109 amino acids, the core motif FGXG in J segment was also found in carp TCR gamma. The C region of carp TCR gamma contains the characteristic CX6PX6WX45C motif. The CP region of carp TCR C gamma contains 37 amino acids. The full length of carp CD3 gamma/delta is 790 bp and encodes 175 amino acids including a signal peptide region of 17 amino acids and a transmembrane region of 23 amino acids from aa 93 to 115. Similar to other known CD3 gamma/delta s, four cysteine residues in the extracellular domain and an immunoreceptor tyrosine-based activation motif ITAM (YxxL/Ix6-8YxxL/I) in the intracellular domain are also included in carp CD3 gamma/delta. Differing from other known CD3 gamma/delta s, carp CD3 gamma/delta tacks the CXXCXE motif in the extracellular domain. RTPCR analysis demonstrated that the expression of TCR gamma gene was mainly in the thymus and gill of 6-month carp, but in 18-month carp, TCR gamma gene was detected in all the examined tissues. The expression of CD3 gamma/delta gene was detected in all examined tissues of 6 and 18-month carp; among them, the highest expression level was in the thymus of 6-month carp. In situ hybridization showed that CD3 gamma/delta-expressing cells were widely distributed in the head kidney, spleen and kidney of carp, whereas in the thymus, they were densely distributed in the lymphoid outer zone and scattered in the epithelioid inner zone. (c) 2007 Published by Etsevier Ltd.