Virulent Salmonella enterica infections can be exacerbated by concomitant infection of the host with a live attenuated S. enterica vaccine via Toll-like receptor 4-dependent interleukin-10 production with the involvement of both TRIF and MyD88.

During systemic disease in mice, Salmonella enterica grows intracellularly within discrete foci of infection in the spleen and liver. In concomitant infections, foci containing different S. enterica strains are spatially separated. We have investigated whether functional interactions between bacterial populations within the same host can occur despite the known spatial separation of the foci and independence of growth of salmonellae residing in different foci. In this study we have demonstrated that bacterial numbers of virulent S. enterica serovar Typhimurium C5 strain in mouse tissues can be increased by the presence of the attenuated aroA S. Typhimurium SL3261 vaccine strain in the same tissue. Disease exacerbation does not require simultaneous coinjection of the attenuated bacteria. SL3261 can be administered up to 48 hr after or 24 hr before the administration of C5 and still determine higher tissue numbers of the virulent bacteria. This indicates that intravenous administration of a S. enterica vaccine strain could potentially exacerbate an established infection with wild-type bacteria. These data also suggest that the severity of an infection with a virulent S. enterica strain can be increased by the prior administration of a live attenuated vaccine strain if infection occurs within 48 hr of vaccination. Exacerbation of the growth of C5 requires Toll-like receptor 4-dependent interleukin-10 production with the involvement of both Toll/interleukin-1 receptor-domain-containing adaptor inducing interferon-beta and myeloid differentiation factor 88.

A Salmonella Typhimurium-Typhi genomic chimera: a model to study Vi polysaccharide capsule function in vivo.

The Vi capsular polysaccharide is a virulence-associated factor expressed by Salmonella enterica serotype Typhi but absent from virtually all other Salmonella serotypes. In order to study this determinant in vivo, we characterised a Vi-positive S. Typhimurium (C5.507 Vi(+)), harbouring the Salmonella pathogenicity island (SPI)-7, which encodes the Vi locus. S. Typhimurium C5.507 Vi(+) colonised and persisted in mice at similar levels compared to the parent strain, S. Typhimurium C5. However, the innate immune response to infection with C5.507 Vi(+) and SGB1, an isogenic derivative not expressing Vi, differed markedly. Infection with C5.507 Vi(+) resulted in a significant reduction in cellular trafficking of innate immune cells, including PMN and NK cells, compared to SGB1 Vi(-) infected animals. C5.507 Vi(+) infection stimulated reduced numbers of TNF-α, MIP-2 and perforin producing cells compared to SGB1 Vi(-). The modulating effect associated with Vi was not observed in MyD88(-/-) and was reduced in TLR4(-/-) mice. The presence of the Vi capsule also correlated with induction of the anti-inflammatory cytokine IL-10 in vivo, a factor that impacted on chemotaxis and the activation of immune cells in vitro.

Observaciones prácticas del uso en Nicaragua del herbicida MSMA

El "MSMA" es un herbicida selectivo y de contacto. Su baja toxicidad y su propiedad de inactivarse al contacto con el suelo, son características que permiten usarlo con poco peligro para el hombre y los animales. Su tolerancia por las plantas del algodonero, hacen que este herbicida sea de mucha utilidad para el control de malezas en dicho cultivo, proporcionando beneficios económicos hasta de C20.00 por manzana. En el cultivo de bananos, su uso ha proporcionado beneficios económicos hasta de C10.00 por manzana por aplicación, a la vez que un control de malezas mas efectivo que el método tradicional de limpiar con machetes. El buen control del zacate Chompipe que se ha obtenido usando este herbicida en plantaciones de Caña de Azúcar, ha proporcionado beneficios economicos, para el control de malezas conocido como Zacaton, el beneficio económico que se obtuvo fue hasta de C70.00 por manzanas. También es muy eficaz para el control de malezas en terrazas y canales de desagüe, consiguiéndose en estos casos un beneficio económico de C5.00 por cada 1000 varas de longitud aplicadas con el herbicida.

Cuantificación de carbono almacenado en árboles de sombra en tres lotes en un sistema de café, en el Centro Experimental ICIDRI – Masatepe de UPOLI

Se realizó un estudio en Instituto de Capacitación e Investigación en Desarrollo Rural Integral (ICIDRI), como parte de una serie de estudios desarrollados por el mismo, que se ubica en el municipio de Masatepe en el departamento de Masaya, tuvo como ob jetivo evaluar carbono almacenado en el componente arbóreo, para lo que se eligieron tres lotes de un sistema de café bajo sombra; El Genízaro (LGR), El Guanacaste (LGT) y El Cinco piso (LCP). Se realizó un censo forestal al 100 % para individuos con diáme tro mayor a 10 cm, encontrándose 24 familias botánicas, 51 especies y 704 individuos; de estos 348 se encontraron LGR, 226 en LCP y 130 en el LGT, las familias sobresalientes fueron las Fabaceaes, Rutaceaes; Sapotaceaes, Anacardiaceaes y Mimosaceae, las es pecies más representativas fueron: Cordia alliodora 19%, Simarouba glauca 17%, Persea americana 13%, y Mangifera indica y Cedrela o dorata con 12% por individual, acumulando el 73% del total. Al realizar un diagnóstico para conocer la calidad de árboles uti lizados como sombra, se definieron 6 categorías llamadas calidad de árboles; individuos sanos (C1), regulares (C2), con podas muy altas (≥50%) (C3), secos y casi secos (C4), con parasitas (C5) y con otro tipo de afectaciones (C6), se encontró que de los tr es lotes evaluados, El Guanacaste, fue el más sano presentando 42% en categoría (C1) y 22% en (C2). El carbono almacenado por lote fue de 108. 0 t C en el LGR, 54.5 t C para el LCP y 26.7 t C para el LGT, esta diferencias en carbono almacenado por lote se debieron a que estos presentan diferencia en área y así mismo en número de individuos y evaluando el carbono registrado por lote se encontró que e stos valores corresponden a 58.4 t C ha. - 1, almacenado en el componente arbór eo del sistema café bajo sombra

Evaluation of a new fishing pot trap (Lege) in River Rima, north western Nigeria

Based on the findings and diagnostic survey, a new fishing trap, christened Lege trap was designed and fabricated, and the performance evaluated. The 8-valve Lege trap was assessed concurrently with Malian and Ndurutu traps by the fishermen in the study area. The experiment was conducted in a randomized complete block design with one factor each replicated three times. Data collected on fish diversity number, biomass and size were subjected to descriptive statistics and analysis of variance. The results showed that 22 fish species belonging to thirteen families were caught. The prototype (Lege) trap recorded higher species diversity index (0.90) than the Malian (0.50) and Ndurutu (0.50) traps. The Lege trap also accounted for the largest number (55%) and biomass (63%) of fish caught which was significantly (P<0.05) higher than those of the Malian and Nduutu traps were. The mean length (15.03~c5.70cm), weight (60.43~c48.61g) and girth (4.77~c1.65cm) of fishes caught in the Lege trap were also significantly (P0.05) higher than those caught in the other two traps. These results demonstrated better performance of the new trap than the two conventional traps, even though the sizes of some of the fish species caught in all the traps were below those allowed by the Sokoto State Fisheries Edict where the study was conducted. Therefore, since it is desirable to develop conservation-oriented trap at a least cost, it is necessary to research further on the number of valves and mesh size of the new trap

Selective hydroxylation of small alkanes by the particulate methane monooxygenase

The particulate methane monooxygenase (pMMO) catalyzes the oxidation of methane to methanol under ambient temperatures and pressures. Other small alkanes and alkenes are also substrates of this enzyme. We measured and compared the initial rate constants of oxidation of small alkanes (C1 to C5) catalyzed by pMMO. Both primary and secondary alcohols were formed from oxidation of n-butane and n-pentane. The alcohols produced from alkane oxidation can be further oxidized, probably by pMMO, to aldehydes and ketones. The apparent regioselectivity for n-butane and n-pentane is 100% 2-alcohols because the formation of primary alcohols is slower than further oxidation of these alcohols. The hydroxylation at the secondary carbons is highly stereoselective: (R)-alcohols are preferentially formed. The enantiomeric excess increases slightly with decreasing reaction temperature. The steric course of hydroxylation on primary carbons was also studied by using isotopically substituted ethane: (S)- or (R)-CH_3-CHDT, and (S)- or (R)-CD_3- CHDT and the reactions were found to proceed with 100% retention of configuration. A primary isotopic effect of k_H/k_D=5.0 was observed in these experiments.

Composição corporal de indivíduos com lesão medular cervical: influência do exercício físico e comparação de métodos

Objetivo: Comparar a composição corporal total e regional e a distribuição de gordura de homens com lesão medular LM cervical fisicamente ativos e não ativos, e sua relação com a concentração de proteína C reativa ultra-sensível (PCR-us). Além disso, identificar um protocolo de impedância bioelétrica (BIA) que forneça resultados de percentual de massa gorda (MG) total concordantes com os obtidos pelo método de referência, absorciometria de dupla emissão de raios-X (DXA). Métodos: Os participantes possuíam lesão medular entre C5-C7 e foram classificados em ativos (n=15) e não ativos (n=10). Consideraram-se ativos os indivíduos que praticavam exercícios físicos há pelo menos três meses, três vezes por semana ou mais, totalizando tempo mínimo de 150 minutos de atividades físicas por semana. A determinação da composição corporal total e regional (braços, pernas e tronco) foi realizada por DXA. A PCR-us foi mensurada por imunoturbidimetria. Os protocolos de BIA testados foram: a) para indivíduos com LM (KOCINA & HEYWARD, 1997); b) para grupos que incluem idosos (GRAY et al 1989); c) validado para idosos brasileiros (DEY et al, 2003). A análise estatística dos dados incluiu ANCOVA para comparar a massa corporal total, composição corporal e PCR-us entre os grupos; e correlação parcial com correção pelo tempo de lesão (TL) para identificar a associação de exercício físico com MG e da PCR-us com exercício físico e MG tronco. A comparação dos resultados de percentual de gordura obtidos por DXA e cada um dos protocolos de BIA foi realizada por ANOVA one way e Dunnet pós teste. A análise de Bland-Altman foi realizada para verificação da concordância entre os métodos testados. Conclusão: O exercício físico praticado de forma contínua e controlada é importante para manter menores valores de MG e evitar acúmulo de gordura na região do tronco. A melhor composição corporal e distribuição de gordura corporal observadas no grupo ativo possivelmente levaram à menor concentração de PCR-us sérica. Juntas, estas adaptações provavelmente contribuíram para a redução dos riscos de desenvolvimento de doenças cardiometabólicas. A semelhança na modificação da composição corporal entre idosos e indivíduos com LM sugere que protocolos de BIA propostos para idosos podem ser adequados para avaliação da composição corporal de indivíduos com lesão medular cervical.

中国株丙型肝炎病毒(HCV)感染猕猴后5^NTR-C区基因组的cDNA序列分析

从2份受丙型肝炎病毒(HCV)感染的献血员血清(CX1、CX2)、第一代感染HCV猕猴血清(CX3)、第二代感染HCV猕猴血清(CX4)中提取RNA, 用自行设计的HCV 5^非编码区和核心区C5^NTR-C区引物进行逆转录PCR, 经扩增克隆并序列分析, 结果显示: CX1 cDNA全长779bp, CX2 cDNA 778bp, CX3 cDNA 776bp, CX4 cDNA 777bp。CX1株和CX4株均在5^NTR nt-216有一C的插入, CX3和CX4区nt385-387处的3个碱基缺失; CX1株与CX2、CX3、CX4比较同源性分别为98.07%、96.15%、95.25%; CX2与CX3、CX4的同源性分别为96.28%、95.76%; CX3与CX4的同源性为97.56%。

24-二甲基戊二稀土化合物的合成

本文叙述了2.4-二甲基戊二烯基稀土金属有机化合物的合成并通过元素分析，红外光谱、核磁共振谱及质谱的鉴定。测定了Gd(2.4-GH_(11))_3的单晶结构，此外还合成了（2.4-GH_(11)K.TMEDA及K_2C_8H_8·3THF并也测定了它们的晶体结构。在所合成化合物的红外光谱中，没有属于C=C双键的吸收峰，表明分子中配位体以η~5形式的大π键体系与稀土金属离子结合，在Ln(2.4-GH_(11))_2Cl·TMF和Ln(2.4-GH_(11))Cl_2·GH_THF的红外光谱中，于1060波数附近出现一强而宽的吸收峰，即化合物中有四氢呋喃分子络合。化合物的室温NMR谱有四个吸收峰，2.4-二甲基戊二烯配位体可能为η~5平面∪或W构型。化合物的水解'H-NMR谱与质谱都证实水解产物为2.4－二甲基－1.3－戊二烯。它是－2.4二甲基戊二烯阴离子水解所得的唯一产物，它表明化合物中的配位体确为2.4－二甲基戊二烯阴离子。(2.4-GH_(11))_2Cl·TMDA配合物晶体结构是应用低温X－射线衍射技术用Nicolet R_3 M/E型四园衍射仪LT－1低温装置并利用重原子法测定的最小二乘法精修至收敛时的一致性因子R=0.055. Rw=0.057。晶体属单斜晶系P21/n空间群。晶胞参数a=11.322(4)A, b=9.242(3)A, c=15.956(5)A. β=106.70(3)分子中2.4－二甲基戊二烯阴离子呈平面∪构型。钾离子与四甲基乙二胺二啮体结合形成的络合阳离子和2.4-二甲基戊二烯阴离子相间排列形成无限链状结构分子。2.4－二甲基戊二烯阴离子的C－C键长明显分为中间与外端C－C键两组。外端组C－C键双性质较强键长较短。表明C3具有负电荷的共振杂化体贡献较大。分子中K－C键最短的是K-C(1.5)。而不是具有较多负电荷的C3－K键。这可能是由于几何因素造成的。K_2C_8H_8·3THF的晶体结构是采用与前者相同的方法测定的。它属三斜晶系，PT空间群，晶胞参数a=10.263(3)A, b=13.157(4)A, c=9.443A, α=87.51(2)°, β=114.93(2)°, γ=76.81(2)°. V=1111.6A, R=0.051. 晶体中负二价的环辛四烯阴离呈平面构型，具有中心对称性，两侧与两中心对称相关的钾离子连接，相邻的非等效的钾离子间通过两四氢呋喃分子的氧原子相连接，从而形成了无限链状结构的分子。环辛四烯反映了Huckel的4n+2芳香性规则。该结构的特别之处在于四氢呋喃分子的氧原子以桥键形式与两个钾离子同时连接。而这种形式的桥键在其它化合物中似还未发现。Go(2.4-GH_(11))_3的晶体结构亦是采用与前述相同的方法测定的。其晶体为三斜晶系，PT空间群，晶胞参数a=12.541A, b=12.853A, c=8.432A, α=91.44°, β=108.61°, γ=117.97°, V=112.54A~3. 结构测定表明，Gd(2.4-GH_(11))_3分子具有C_3h对称性。三个配位体阴离了的九个带负电荷的碳原子近似以三帽三角棱柱形式与钆离子配位。分子中2.4－二甲基戊二烯阴离子的C－C键长－亦分为而组。外端C－C键较中间C－C键强，键长较短，亦表明C3具有较多的负电荷。2.4－二甲基戊二烯阴离子本身近似呈平面∪构型。C2,C4偏离由C1 C3 C5三碳原子构成的平面0.067A。方向上远离中心钆离子。可能在此以离子性为主的化合物中，钆离子与不带电荷的C2 C4间的相互作用有些排斥性质。与Nd(2.4-GH_(11))_3不同的是，在Gd(2.4-GH_(11))_3分子中，Gd-(C(1,5）键最短，而不是Gd-C(3)键。这可能是由于钆离子的半径较小，化合物的空间位阻效应较大所致。

用反应窗理论研究离子与原子碰撞的态选择微分截面

基于描述低能离子与原子碰撞的分子库仑过垒模型,详细阐述了与入射离子速度相关的反应窗理论,并对影响势垒变化的平均径向速度做了修正.根据该理论,计算了C5+-He和He2+-He碰撞体系单电子俘获过程的态选择微分截面,并分别与Kamber等人和Mergel等人的实验结果进行了比较.

Injection system design for a hadron therapy synchrotron

A synchrotron is designed for tumour therapy with C6+ ions or proton. Its injector is a cyclotron, which delivers C5+ or H-2(+) ions to the synchrotron. After comparing the methods of the single-turn injection, the multi-turn injection and the stripping injection, this paper chooses the stripping injection method. In addition, the concept design of the injection system is presented, in which the synchrotron lattice is optimized.

Skeletal isomerization of 1-hexene to isohexenes over zeolite catalysts

Several zeolite catalysts such as SAPO-11, ZSM-11, ZSM-12, etc. were selected to convert I-hexene to branched hexenes in this work. Pore size of the zeolite catalyst plays an important role on the yield and the distribution of branched isohexenes. And the zeolite catalysts with the pore size of 0.6nm are optimum to produce dimethylbutenes (DMB). SAPO-11 zeolite is a suitable skeletal isomerization catalyst, especially in the production of methyl pentenes. Under the following reaction conditions: WHSV=1.0 h(-1), H-2/hexene=8, T=250 degreesC, P=0.2 MPa, the yield of skeletal isohexenes remains above 80% at the prolonged time-on stream of 80 h, accompanying low C5-, C7+ products and low carbon deposition on the catalyst.

麂属动物以及六带犰狳DNA重复序列家族的克隆、序列分析和染色体定位

1．黑麂和费氏麂卫星DNA的克隆、序列分析和染色体定位 麂属动物在很短的时间内经历了快速的物种辐射，并且种间染色体数目存在巨大差异，是研究动物核型进化和物种起源的理想模型。近二十年来的分子细胞遗传学研究已基本上证实染色体串联融合(端粒－着丝粒融合)是麂属动物核型演化的主要染色体重排方式。尽管染色体串联融合的分子机制仍不清楚，但研究提示着丝粒区域的卫星DNA可能介导染色体的非同源重组。因此，着丝粒卫星DNA的克隆、分析序列以及染色体定位研究不仅有助于阐明麂属染色体核型演化规律，还可能揭示染色体串联融合的分子机制。迄今为止，上述研究工作已经在赤麂、小麂和小麂台湾亚种开展过。但是，尚无有关黑麂、费氏麂和贡山麂卫星 DNA 克隆、序列分析以及染色体定位研究的报道。 在本研究中，我成功地克隆了黑麂的卫星DNA I、II和IV，分别命名为BMC5、BM700和BM1.1k，并且从费氏麂中克隆了卫星DNA II，命名为FM700。对这些卫星DNA克隆进行序列分析，并将这些克隆探针分别与黑麂、费氏麂、贡山麂和小麂的染色体杂交。研究结果表明： 1)黑麂的卫星DNA I(BMC5)与小麂卫星DNA I(C5)序列高度相似，并且在小麂、黑麂、费氏麂和贡山麂染色体上的大部分串联融合位点处均有分布，因此卫星DNA I可能代表着染色体发生串联融合后保存下来，来源于麂属动物祖先染色体着丝粒的一种卫星DNA。卫星DNA I在这四种麂属动物染色体上的分布也表明黑麂、费氏麂和贡山麂与赤麂的核型演化过程相似，很可能从一个2n ＝ 70的共同祖先通过一系列的串联易位进化而来。 2) 将卫星DNA II（BM700和FM700）克隆探针分别杂交到黑麂和费氏麂的染色体上，只检测到几对间隔分布的信号。这提示在核型进化过程中不同卫星DNA间可能发生了广泛的重组，从而导致卫星DNA II大量丢失。大部分重组断裂位点可能位于卫星DNA I 与卫星DNA II之间，或者在卫星DNA II 区域内。 2．六带犰狳重复序列家族的克隆、序列分析和染色体定位 六带犰狳属于犰狳科、贫齿目，是六带犰狳属中唯一的一个代表物种。系统发育研究认为贫齿目与非洲兽总目是有胎盘哺乳动物中最原始的两个类群。C显带结果揭示六带犰狳30%的基因组是由组成性异染色质构成的，并且C带分布的位置也较复杂，提示在六带犰狳基因组中存在多种重复序列元件。 为了研究六带犰狳异染色质的组成，我从六带犰狳的基因组中克隆了七种位点特异性的重复序列。根据测序结果以及它们在染色体上的分布，将这些重复序列分为五个重复序列家族。其中AMD-EcoRI 837与AMD-BglII 811的序列相似，都是由大小约116 bp的单位组成，分布在大多数染色体的着丝粒区域，同时在一些染色体臂也有分布。AMD-EcoRI 832，AMD-EcoRI 836和AMD-EcoRI 934是特定染色体的重复序列，并且都分布于着丝粒区域。另外，AMD-BglII 634，AMD-EcoRI 731两个克隆都属于长散在分布重复序列(L1)，倾向于分布在G带阳性、富含AT碱基的区域，并且这两种重复序列在染色体上的定位与C带阳性的非着丝粒的异染色质区域很相似。本研究提供了六带犰狳异染色质区域的部分基因组信息，并且这些重复序列家族也可以用于研究六带犰狳及其近缘物种的系统发育关系。

反刍动物的比较分子细胞遗传学研究

1. 反刍动物核型演化研究 反刍亚目是偶蹄目中最大的亚目，包括鼷鹿下目(鼷鹿科)和有角下目(叉角 羚羊科、长颈鹿科、麝科、牛科和鹿科)。许多物种具有巨大的经济价值（如： 牛，羊，鹿和麝，等）和重要的科学研究价值（如麂类动物）。对反刍动物进行 细胞遗传学研究，不仅可以为动物遗传育种和驯化提供重要的理论依据和合理 建议，也可以为生物演化等基础科学研究提供新的见解和理论阐释。种间染色 体涂色可以快速、准确地检测物种间全基因组水平上的同源性，已经成为比较 细胞遗传学研究的首选技术。通过构建物种间的染色体同源图谱，分析保守的 同源染色体片段在不同物种、不同类群核型中的分布和排列方式，可以推导各 类群可能的祖先核型并重建伴随物种形成所发生的基因组结构变化(包括染色 体重排的类型、速率和核型演化的趋势等)，为系统发育关系研究提供重要的细 胞遗传学证据。 本研究首次通过种间染色体涂色技术，利用小麂染色体特异探针，大规模 建立了小麂与牛科、鹿科及长颈鹿科代表物种间的染色体同源关系，阐明了其 核型演化中所发生的染色体重排，并以染色体重排为特征，构建了反刍动物各 类群的核型系统发生树。结果表明：1) 有角下目动物的共同祖先核型为2n=58， 牛科2n=60 的祖先核型和鹿科2n=70 的祖先核型都由共同祖先核型经过染色体 分离演化而来；2）与鹿科动物的核型相比，麝科动物与牛科动物的核型比较保 守，更接近共同祖先的核型，二者共有更多的核型特征；3）在有角下目的绝大 多数类群中，罗伯逊易位是导致核型多样化的主导染色体重排方式；鹿科的麂 亚科是个例外，染色体间不断地串联融合使其核型发生了迅速而极端的变化, 导致现生各种极大的核型差异；4）长颈鹿的核型演化较为复杂，除了广泛的罗 伯逊易位外，还涉及到其它类型的染色体重排，如，着丝粒位置变化、串联融 合及染色体内部倒位。现在，黄牛的基因组序列已拼接完毕，鹿、羊的基因组 测序正在进行，本论文中构建的反刍动物间的染色体同源图谱有助于将已有的基因组序列信息向其它反刍动物转移。 2. 麂属动物染色体演化研究 鹿科的麂属动物以快速的物种辐射、迅速而极端的核型演化和不断的新种 发现成为染色体重排与物种形成研究的理想模型。已有的细胞遗传学研究证明 麂属动物的祖先核型为2n=70，染色体间的串联融合是导致其核型迅速演化， 染色体数目急剧降低的主要原因。但是，关于麂属动物核型演化，还有很多问 题没有解决，如，黑麂、贡山麂、费氏麂核型演化中串联融合的类型没有确定， 导致串联融合的分子机制依然不清楚。 本研究利用比较BAC 定位技术首次构建小麂－黑麂、小麂－贡山麂、小麂 －费氏麂、小麂－毛冠鹿染色体间的比较BAC 图谱，研究结果丰富和发展了“串 联融合假说”的内容，对麂属动物的核型演化提出了新的阐释：1）在毛冠鹿、 黑麂、贡山麂和费氏麂的核型演化中所发生的串联融合均为着丝粒－端粒型融 合；2）黑麂1p+4 染色体的演化大体经历了三个步骤，主要涉及染色体易位和 臂间倒位；1p+4 的存在使雄性黑麂具有独特的X1X2Y1Y2Y3 性染色体系统， 1p+4 可以看作新的Y染色体(neo-Y),将是哺乳动物性染色体起源研究的理想模 型； 3）黑麂、贡山麂和费氏麂各自有独特而稳定的基因组结构和核型特征， 支持它们各自为独立的种。此外，实验中筛选出的70 个麂类着丝粒特异的或 C5 样的重复序列克隆将有助于研究麂类基因组中重复序列的类型、组成、结构、 演化及导致串联融合频繁发生的分子机制.

Novel NIR-absorbing conjugated polymers for efficient polymer solar cells: effect of alkyl chain length on device performance

Three low bandgap conjugated polymers, i.e., PDTPBT-C8, PDTPBT-C6 and PDTPBT-C5, which consist of alternating N-alkyl dithieno[3,2-b: 2',3'-d] pyrrole and 2,1,3-benzothiadiazole units and carry 1-octylnonyl, 1-hexylheptyl and 1-pentylhexyl as side chains, respectively, were synthesized. These polymers show strong absorption in the wavelength range of 600-900 nm with enhanced absorption coefficient as the length of alkyl chain decreases. The film morphology of the polymers and 1-(3-methoxycarbonyl) propyl-1-phenyl-[6,6]-C-61 (PCBM) blends is also dependent on the alkyl chain length. As the length decreases, the film becomes more uniform and the domian size decreases from 400-900 nm for PDTPBT-C8 to similar to 50 nm for PDTPBT-C5.