331 resultados para 5-MUC 3


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以自然土壤、沉积物样品为研究对象,研究了1,3,5-三氯苯在样品上的等温吸附过程。结果表明,线性模型和Freundlich模型能较好地拟合所有样品的等温线,而双区位反应模型(DRDM)适用范围有限。研究表明,三氯苯的吸附容量大小主要取决于样品中有机碳的含量,并且与不可提取态有机质和粘土矿物含量有一定的关系。以自然土壤、沉积物样品为研究对象,研究了1,3,5-三氯苯在样品上的等温吸附过程。结果表明,线性模型和Freundlich模型能较好地拟合所有样品的等温线,而双区位反应模型(DRDM)适用范围有限。研究表明,三氯苯的吸附容量大小主要取决于样品中有机碳的含量,并且与不可提取态有机质和粘土矿物含量有一定的关系。

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To test preschoolers’ development of cognitive flexibility--an ability to solve a problem in one way and to then switch solution strategies, and the mechanism involved in the development, 3-5-year-olds are asked to perform switching tasks in which the experimenter manipulates the way the stimuli are presented: consecutive or simultaneous; the way the switching happens: between dimensions or within a dimension; the conceptual domains involved: shape, color, number and direction; the specific labels used. The main results of this work are presented below: (1) 3-5-year-olds’ cognitive flexibility develops with age, yet its development is not of the same speed in extra-dimensional switch tasks and inter-dimensional reversal tasks. 3-year-olds manifest some cognitive flexibility, but their performance is significantly worse than that of 4- and 5-year-olds. For the 3-year-olds, in reversal tasks, although 80% of the children passed the post-switch phrase in color task; less then 60% children passed the post-switch phrase in shape, number and direction tasks. In extra-dimensional tasks, 3-year-olds performance is worse than that in the reversal tasks. Less than 50% of the children passed the tasks. Children’s cognitive flexibility develops fast from 3-year-olds to 4-year-olds. Both 4-year-olds and 5-year-olds demonstrate high flexibility without significant difference between them. (2) Children’s flexibility in the conceptual domains of shape, color, number and direction follows different developing patterns. In inter-dimensional reversal tasks, 3-year-olds’ performance is not the same in the 4 conceptual domains, but the difference among the domains is insignificant in 4-and-5-year-olds. In extra-dimensional switching tasks, children’s performance on the 4 domain tasks is significantly different from one another in 3-, 4-, and 5-year-olds. (3) The way the stimuli are presented affects children’s development of cognitive flexibility. In inter-dimensional reversal tasks, 3-year-olds’ performance in consecutive presentation is significantly better than that in simultaneous presentation. 4- and 5-year-olds’ performance in the 2 presentations is not significantly different from each other. In extra-dimensional switch tasks, 3-, 4-, and 5-year-olds’ performance in the consecutive presentation is not significantly better than that in the simultaneous presentation (4) 3-, 4-, and 5-year-olds’ self-issued labeling aids their performance on the switching tasks. Children’ performance in the labeling condition is significantly better than that of no labeling. (5) 3-5-year-olds’ cognitive flexibility is highly correlated with their working memory and inhibition. Children’ development of cognitive flexibility is a process that involves activation of working memory and inhibition, in which the complexity of the task also plays a role.

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三块掺杂率均为5%的Yb^3+激光晶体Yb:LSO、Yb:GSO和Yb:GYSO在完全相同的实验条件下由同一块熔融石英棱镜实现了可调谐激光的输出,调谐范围分别为70nm、66nm和74nm.在输出镜透过率为6%时,LSO晶体的光-光转换效率为38.3%;GSO晶体在三者中容易获得更长波长的高功率输出;GYSO晶体由于具有较为平滑的调谐曲线而更容易获得锁模激光.

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目的 :探讨 p5 3基因在乳腺癌发生早期的作用。 方法 :用免疫组化方法检测 36例乳腺单纯性增生、31例不典型增生、14例原位癌和 16例浸润癌中 p5 3蛋白的表达 ,用PCR SSCP检测了上述组织中 p5 3基因第 5外显子突变。 结果 :p5 3蛋白在单纯性增生、不典型增生、导管内癌、浸润癌中的表达率分别为 0、2 2 6 % (7/ 31)、42 8% (6 / 14)、5 0 % (8/ 16 ) ,PCR SSCP在各组中均未检测到该基因第 5外显子突变。结论 :乳腺癌发生早期阶段有 p5 3基因的参与 ,但与第 5外显子突变无明显关系

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研究了地木耳(Nostoc commune)、葛仙米(N.sphaeroides)和发菜(N.flagelliform e)3种念珠藻多糖对自由基的清除作用。结果表明,3种念珠藻多糖对超氧阴离子自由基和羟自由基具有很强的清除作用,且呈量效关系,地木耳清除超氧自由基作用最强,最高清除率达72.3%,葛仙米和发菜分别为46.7%、35.5%;发菜清除羟自由基效果最强,最高清除率达74.3%,葛仙米和地木耳清除率分别为49.0%、46.7%;3种念珠藻多糖对DPPH自由基的清除作用不显著。

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用~(35)S-Met在照光下与豌豆完整叶绿体保温,显示新合成的标记的RubisCO大亚基与结合蛋白形成一复合物,经ATP处理后解离为结合蛋白亚基,同时释放出的标记的RubisCO大亚基参与了RubisCO的装配。豌豆叶片提取液经热处理,硫酸铵分部,DEAE-Sepharose fast flow和Sephacryl S-300柱层析在ND-PAGE,SDS-PAGE上显示为一条带,估计纯度达90%以上,得率比以前报道的高12倍。纯化的结合蛋白表面巯基数经测定为12±1个,总巯基数为36±1个。远紫外CD

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The YCo5.0-xMnxGa7.0 compounds crystallize with the ScFe6Ga6-type structure. The lattice of YCo5.0-xMnxGa7.0 expands with the increase of the Mn content for 0.05 <= x <= 2.5, but the lattice of YCo2.0Mn3.0Ga7.0 shrinks compared with YCo2.5Mn2.5Ga7.0. The shrinkage of the lattice is attributed to the magnetostriction of YCo2.0Mn3.0Ga7.0. The substitution of Mn for Co forms magnetic clusters in the antiferromagnetic matrix. The magnetic frustration results in the spin-glass-like behavior for 0.8 <= x <= 1.5 and the difference between zero-field-cooling (ZFC) and field-cooling (FC) magnetizations for x = 2.0, 2.5, and 3.0. A stable long-range magnetic ordering appears among the Mn-centered magnetic clusters with the ordering temperature 110 K for x = 2.0. The hump in the thermomagnetization of YCo3.0Mn2.0Ga7.0 can be attributed to the competitive effects between the thermal fluctuation and the enhanced magnetic interaction. Both the hump and the bifurcation between the ZFC and the FC magnetizations of YCo3.0Mn2.0Ga7.0 occur at lower temperatures as the applied field increases. On the two-step magnetization curve of YCo3.0Mn2.0Ga7.0, the inflection point at 4000 Oe is due to the coercive field, and the magnetic moments in the clusters are tilted to the applied field above 4000 Oe. The magnetic ordering temperature is further increased to 210 K for x = 2.5 and to 282 K for x = 3.0. The spontaneous magnetization of YCo2.0Mn3.0Ga7.0 is 0.575 mu B/f.u. at 5 K with a canted magnetic structure.

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在离心机模拟不同水吸力条件下,研究了聚丙烯酸钠(sodium polyacrylate记作SP)5种使用浓度(占干土质量0,0.01%,0.08%,0.2%与1%)对3种土壤(砂土、壤土、黏土)持水能力的影响;采用大田试验研究了地表撒施2 g/m2SP对冬小麦与下季玉米产量及WUE影响。结果表明:3种土壤在0.01 MPa至1.5 MPa水吸力下的持水能力随着SP用量的增加而增加,砂土的作用效果较壤土、黏土更显著;3种土壤适宜浓度为0.08%~0.2%,最佳用量为0.2%,此用量条件下砂土、壤土、黏土的最大毛管持水量分别较对照增加了138.61%,7.22%,62.70%;不灌水条件下,SP处理较不施用SP冬小麦增产4%,WUE增加5.7%,灌浆期灌水28.5 mm条件下SP处理较不施用SP增产1%,WUE降低1%;SP处理的玉米产量较对照降低0.5%,WUE提高3%,效果明显低于对冬小麦效果。

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AAO模板具有高度有序的纳米孔阵列,其孔径可以在5一200nm范围内调节,利用AAO模板进行纳米组装已成为纳米结构材料组装的重要技术之一。目前,采用该技术已经制备出了金属、半导体、碳、导电高分子以及其它材料构成的纳米管、纳米线、纳米纤维、电缆等纳米结构单元和有序纳米阵列材料,同时,研究了它们的光、电、磁和催化等特性及其在光学材料、铿电池的电极材料、垂直磁性记录材料和光催化剂等方面的潜在应用。然而,有关稀土发光材料的AAO模板合成及其性质还鲜见报道。本论文采用二次阳极氧化技术制备出了具有高度有序纳米阵列孔的AAO模板。采用溶胶一凝胶法和水热法对稀土发光材料M2O3:RE3+(M=Y,Gd; RE=Eu,Tb)体系进行了AAO组装,得到了纳米线、纳米管及其纳米线阵列。对AAO模板和组装样品的形貌、结构和光谱性质进行了表征,得到了一些令人感兴趣的研究结果,其主要的结果和结论总结如下:(1)采用二次阳极氧化法制备出了孔径约为5Onm、35nm和2Onm等系列高度有序纳米阵列孔的基体铝支持的AAO模板和独立支撑的AAO模板。(2)XRD测试结果表明:退火后的基体铝片,其331晶面优先结晶生长,这有利于高度有序纳米阵列孔AAO模板的制备。使用这些退火后的铝片,通过二次阳极氧化法制备的高度有序纳米阵列孔AAO膜为非晶态,并且在退火后转变为γ-Al2O3。(3)未退火的基体铝支持的AAO模板,在350一600nm范围内发出较强的蓝光,其峰值波长位于435nm。该蓝光发射带经过程序控温慢慢退火后完全消失,这说明它产生于缺陷发光中心。(4)采用溶胶一凝胶法,利用AAO模板首次合成出了(YO.96RE0.05)O3(RE=Eu,Tb)纳米线及其阵列,并通过SEM、EDX、TEM、SAED、XRD和PL分析测试加以确认。x-射线衍射(XRD)和选区电子衍射(SAED)的结果证明,这些纳米线主要是由立方相的RE2O3(RE=Y或Gd)多晶材料组成的。光谱测试结果表明,同体相材料相比,Eu3+的,D0一7F2跃迁发射峰和Tb3+的5D4一7FJ(J=6,5,4,3)跃迁发射峰出现了宽化,这种现象可能是纳米颗粒的表面界面效应所引起的非均匀宽化造成的。(5)首次观察到利用溶胶一凝胶法组装的一部分M2O3:RE3+(M=Y,Gd;RE=Eu,Tb)样品,沿着AAO模板阵列孔壁的边沿所形成的网状结构,并初步地探讨了其形成的机理。(6)对于M2O3:RE3+(M=Y,Gd;RE=Eu,Tb)体系,仅仅依靠毛细作用是难以充分地将溶胶前驱液组装进从O模板的阵列孔中。(7)首次利用水热合成法,在中性条件介质下,将(Y,Gd)2O3:Eu3+样品充分地组装进了AAO模板的纳米孔道中,这说明水热产生的高压可以作为AAO模板组 装样品的驱动力。(8)以M2O3: RE3+(M=Y,Gd;RE=Eu,Tb)溶胶或氢氧化物沉淀作为前驱物,分别在酸性和碱性条件下,进行了从0模板水热合成组装。实验结果表明,AAO模板被部分地损坏。但在碱性条件下的高压釜中,却得到了单晶纳米管、纳米片和纳米棒。

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本文内容包括Tb~(3+)、Pr~(3+)、Ce~(3+)的光氧化。研究了各种因素对氧化率或四价离子生成量的影响。在Tb~(3+)光氧化的基础上,建立了混合钇族稀土中Tb的光化学分析法及混合稀土中Tb的化学氧化分析方法。Tb~(3+)、Pr~(3+)的光氧化是开创性的工作,Tb的分析方法具有一定的应用价值。1 Ce~(3+)d HZO_3-HClO_4体系中的光氧化 用低压汞灯(254nm)、高压汞灯(366nm)和氩离子激光器(351/364nm, 458 nm, 477nm, 502 nm, 514, nm)光辐照Ce~(3+)-HZO_3-HClO_4溶液,Ce~(3+)发生光氧化反应,生成Ce(ZO_3)_4沉淀 。在低压汞灯254 nm波段可获得较高的氧化率,具它波段下的氧化率低,以低压汞灯为光源辐照。研究了温度、光强、酸度、Ce~(3+)初始浓度及辐照时间对氧化率的影响。降低酸度,选择较高的温度和较大的光强,有利于Ce~(3+)的光氧化。2 Tb~(3+)在KIO_4-KOH体系中的光氧化 用高压汞灯(366nm)光辐照Tb~(3+)-KIO_4-KOH溶液,首次实现了Tb~(3+)的光氧化。研究了碱度、络合剂浓度,Tb~(3+)初始浓度、辐照面积,光强和辐照时间等因素对Tb~(4+)生成的影响。测定了Tb(IV)/Rb(III)的氧化还原电势。适宜的KOH浓度应大于0.3M,KIO_4的浓度要比Tb~(3+)初始浓度大几个数量级。当KOH=0.6M, KIO_4=0.22M, 温度为13 ℃时。E_(Tb(IV)/Tb(III))=0.68优,生成的Tb~(4+)可溶性络离子为红棕色,最大吸收峰在420nm附近,比较稳定。3 用光氧化法分析钇族混合稀土中的Tb 根据Tb~(3+)在KIO_4-KOH体系中的光氧化反应,建立了钇族混合稀土中Tb的分光光度分析方法。在高压汞灯366nm的光辐照不无色的Tb~(3+)转变为红棕色的Tb~(4+),其谱带的吸收峰值在420nm,其它三价钇族稀土无此反应,故无千扰,在Tb的分析浓度范围为1*10~(-5)M - 1*10~(-3)M时,符合Beer定律,Tb在钇族混合稀土中含量的分析最低限为0.2%。此方法可用于萃取钇族稀土过程中Tb的分析,方法简便快速。4 用化学氧化法分析混合稀土中的Tb 根据Tb~(3+)在KIO_4-KOH-K_2S_2O_8体系中的氧化反应,建立了混和稀土中Tb的分光光度分析方法。Tb~(3+)-KzO_4-KOH-K_2S_2O_8溶液加热,Tb~(3+)被氧化的Tb~(4+),其颜色由无色转变为红棕色,最大吸收峰在420nm。Ce~(3+)加入KIO_4-KOH溶液后,立即被完全氧化为Ce~(4+), Ce~(4+)在420nm也有吸收,其干扰可以在本底中排除,其它三价稀土离子在此体系中不能发生氧化反应,故无干扰。在Tb的分析浓度范围为5*10~(-5)-5*10~(-4)M时,符合Beer定律,Tb在混合稀土中含量分析的最低限为1%。此方法可用于萃取稀土过程中Tb的分析和监控,方法简便快速。5 Pr~(3+)在KZO_4-KOH体系中的光氧化用高压汞灯光辐照Pr~(3+)-KZO_4-KOH溶液,首次实现了Pr~(3+)的光氧化。生成的Pr~(4+)为棕褐色,最大吸收峰在400nm附近,稳定性较差,在水溶液中发生自还原反应。按Pr~(4+)在400nm的吸收峰值,研究了辐照时间,Pr~(3+)初始浓度,KOH浓度、KZO_4浓度及Ce~(4+)共存时对Pr~9(4+)生成的影响。相应增加KOH及KZO_4用量,有利于Pr~(4+)的生成,Ce~(4+)对Pr~(3+)的光氧化无所谓的“带同氧化作用”。

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5-氟尿嘧啶(5-Fluorouracil, 5-FU)是一种抗代谢药物,广泛用于临床治疗结直肠癌、胃癌、乳腺癌等多种癌症,但其首过代谢显著、亲脂性较低,选择性差、毒副作用大。为克服这些缺点人们对5-FU进行了大量的修饰工作,包括小分子修饰以及与各种载体形成微球、微囊、纳米粒、共价前药等。 环糊精(Cyclodextrin,简称CD),可被结肠中的糖苷酶特异性地降解成小分子糖,而胃和小肠中由于缺乏相应的酶而使环糊精不被降解,这一特性在结肠药物的靶向输送及释放中有重要应用价值。环糊精中含有丰富的羟基,易进行化学修饰,将药物与环糊精通过共价键结合制成前药,使其在胃和小肠中不降解,而在盲结肠中被特异性的酶降解释出药物,达到结肠靶向释药的目的。研究表明,环糊精作为一种前药载体为结肠靶向释药和缓释、控释系统提供了一种有效的手段。 本工作选择5-氟尿嘧啶为模型药物、β-环糊精作为载体,通过中间体5-FU羧酸衍生物的制备及其与β-环糊精的偶联,合成了系列5-FU-β-CD前体药物,并利用紫外、红外、质谱、核磁、元素分析、热分析等手段对其进行结构表征。同时,还研究了前体药物的体外释药性质。具体内容包括: 1. 含有羧基的5-FU衍生物中间体的合成:(5-氟尿嘧啶-1-基)-乙酸(FUAC)、3-(5-氟尿嘧啶-1-基)-丙酸(FUPC)、5-(5-氟尿嘧啶-1-基)-戊酸(FUVC)的合成。 2. 中间体5-FU的羧酸衍生物与β-CD的偶联:分别通过以6-OTs-β-CD为中间体的取代法和活化酯法,合成了第一面取代和第二面取代的5-FU-β-CD大分子前体药物。在二面取代的前体药物制备中,通过改变原料的比例,合成了系列不同取代度(DS)的2-[(5-氟尿嘧啶-1-基)-乙酰基] -β-环糊精结合物。 3. 对上述前体药物进行体外释放研究:分别考察了前体药物在不同pH缓冲溶液中的水解行为及其在小鼠胃肠道人工体液中的酶解行为,并通过UV-Vis及HPLC对前体药物释放情况进行检测分析。 5-Fluorouracil(5-Fu), commonly known as a broad-spectrum antineoplastic drug, has been widely used in the treatment of various kinds of cancer including colon cancer for 40 years. However, this antitumor agent exhibits serious adverse effects, such as their marrow toxicity, gastrointestinal reaction and low selectivity in their clinical use. In order to improve its antitumor activity and reduce its toxicity, the compound was modified in various ways, including the formation of conjugated prodrugs with kinds of carrier, microsphere and nanoparticles etc. Cyclodextrins(CDs) are known to be barely capable of being hydrolyzed and only slightly absorbed in passing through the stomach and small intestine; however they are fermented into small saccharides by colonic microflora and thus absorbed as small saccharides in the large intestine. This biodegradation property of CDs may be useful as a colon-targeting carrier, and thus CD prodrugs may serve as a source of site-specific delivery of drugs to colon. It was demonstrated that prodrugs of CDs can provide a versatile means for construction of not only colon targeted delivery systems, but also delayed release systems. 5-Fluorouracil was taken as a model drug and β-CD as the carrier in this study. Series prodrugs of 5-FU was prepared through the preparation of reactive 5-FU derivatives containing carboxyl group and coupling to hydroxyl groups of CD. The structures of the conjugates were charactered by using IR, UV–vis, ESI-MS, 1H, 13C-NMR spectra, elemental analyses, and thermal analysis. In vitro hydrolysis behavior in aqueous solution and in rat gastrointestinal tract contents of the conjugates were also investigated. The main content of this dissertation includes following aspects: 1. The preparation of 5-FU derivatives containing carboxyl group: 5-Fluorouracil- acetic acid(FUAC)、3-(5-FU-1)-propionic acid (FUPC)、and 5-(5-FU-1)-valeric acid(FUVC). 2. The coupling of 5-FU derivatives to β-CD: 5-FU was selectively conjugated onto the primary or secondary hydroxyl groups of β-CD through an ester linkage, by the substitution of 6-OTs-β-CD and the activated ester method respectively. For the secondary face conjugation, the degree of substitution(DS) can be controlled by changing the mole ratio of the starting materials(FUAC and β-CD). 3. In vitro release behavior of the conjugates in aqueous solution and in rat gastro- intestinal tract contents of the conjugates were investigated, and the reaction was monitored and analyzed by using UV-Vis and HPLC methods.

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在田间完全旱作条件下采用3个密度和2种播种方式观察了3种多年生豆科牧草生长第2年对土壤水分的消耗利用情况。结果表明:苜蓿主要耗水深度在2~3 m,最深可达5 m,其中、高密度处理3 m以上土壤水分含量都在稳定田间持水量之下,已经开始形成土壤下伏干层;沙打旺耗水深度在0~2 m,最低含水量(11.61%)处于80~100 cm,在雨季可以恢复到稳定田间持水量之上;达乌里胡枝子主要耗水深度在1 m以上,最低含水量也在稳定田间持水量之上。单播沙打旺、苜蓿和达乌里胡枝子全生长期内对土壤水分的消耗分别为249.9、180.2和136.6 mm,水分利用效率分别是29.39、26.04和8.91 kg.mm-1.hm-2。混播、加大播种密度都会增加3种牧草土壤水分消耗,降低土壤储水量,提高干草产量和水分利用效率,但影响程度因牧草种类、播种方式以及不同的生长时段而异。

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通过Stille偶联反应合成了5,5″-二辛基-2,2′∶5′2″-三联[3,2-b]并二噻吩,并对该化合物的物理化学性质以及真空蒸镀薄膜的结构和形貌进行了详细表征.以这一化合物作为半导体层、采用顶电极结构制备了有机薄膜晶体管,并对薄膜生长基底温度做了优化,发现基底温度为100℃时器件性能最好,迁移率达到0.13 cm2/V.s,开关比为7×103,阈值电压为-19V.

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beta-NaYF4:Ln(3+) (Ln = Eu, Tb, Yb/Er, and Yb/Tm) hexagonal microprisms with remarkably uniform morphology and size have been synthesized via a facile hydrothermal route. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra as well as kinetic decays were used to characterize the samples. It is found that sodium citrate as a shape modifier introduced into the reaction system plays a critical role in the shape evolution of the final products. Furthermore, the shape and size of the products can be further manipulated by adjusting the molar ratio of citrate/RE3+ (RE represents the total amount of Y3+ and the doped rare earth elements such as Eu3+, Tb3+, Yb3+/Er3+, or Yb3+/Tm3+). Under the excitation of 397 nm ultraviolet light, NaYF4:xEu(3+) (x = 1.5, 5%) shows the emission lines of Eu3+ corresponding to D-5(0-3) -> F-7(J) (J = 0-4) transitions from 400 to 700 nm (whole visible spectral region) with different intensity, resulting in yellow and red down-conversion (DC) light emissions, respectively.

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Efficient synthetic procedures for the preparation of beta-trithiophenes (dithieno[2,3-b:3',2'-d]thiophene) and two macrocyclic compounds, tetra[2,3-thienylene] and hexa[2,3-thienylene] bearing trimethylsilyl (TMS) groups from 2,2'-dibromo-5,5'-bistrimethylsilanyl[3,3']bithiophenyl are reported. The UV-Vis spectra property and crystal structures of these macrocyclic oligothiophenes are described.