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In the presence of 1,10-phenanthroline (phen), lanthanide chlorides LnCl3 reacted with cyclopentadienylsodium to give the novel complexes [Na.3phen]+[Ln(C5H5)3Cl]-.phen (Ln = La, Pr or Nd). In the praseodymium case, crystal structure analysis showed that

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本文对真鲷心跳期胚胎对5种常用渗透性抗冻剂(DMSO、甘油、甲醇、丙二醇、乙二醇)和3种非渗透性抗冻剂(PVP、PEG-8000、蔗糖)的耐受性进行了研究。渗透性抗冻剂分6个浓度梯度(5%;10%;15%;20%;25%;30%)和3个时间组(10min;30min;1h)。非渗透性抗冻剂中,PVP、PEG-8000分3个浓度梯度(5%、10%、15%)和2个时间组(10min、30min),蔗糖为4个浓度梯度(5%、10%、15%、20%)和2个时间组(10min、30min)。实验结果表明,在渗透性抗冻剂组中,浓度为5%的处理组的孵化率(>90%)与对照组差异均不显著,随着抗冻剂浓度增大及处理时间的延长,真鲷心跳期胚胎的孵化率显著下降(P<0.05),在最高浓度的最长处理时间中胚胎孵化率均降到了0。总体上,真鲷心跳期胚胎对五种渗透性抗冻剂的耐受性从小到大依次为:甲醇 < 甘油 < 乙二醇 < DMSO < 丙二醇。对影响胚胎孵化率的三个因素(抗冻剂、浓度、时间)进行的因素效应分析结果表明,三种因素对孵化率的影响显著(P<0.05),并且浓度效应 > 时间效应 > 抗冻剂效应。在非渗透性抗冻剂组中,蔗糖组胚胎孵化率未呈显著变化;PVP组随着浓度及时间的增大,孵化率显著下降(P<0.05);PEG-8000组随着浓度增大孵化率显著下降(P<0.05),但在两个时间组间差异不显著。相同处理情况下PEG-8000对真鲷心跳期胚胎的毒性要小于PVP。因素效应分析比较结果表明仅时间效应不显著,且抗冻剂效应 > 浓度效应 > 时间效应。 对所用各种抗冻剂进行了渗透压测量,实验中使用的渗透性抗冻剂(5%-30%)的渗透压值在959-7980mOsm/kg之间,均高于使用海水的渗透压值(919mOsm/kg);使用的非渗透性抗冻剂的渗透压值在316-1040mOsm/kg之间,除20%蔗糖渗透压值(1040mOsm/kg)高于海水外,其他非渗透性抗冻剂的渗透压值均要低于海水。对孵化率与相应的溶液渗透压值进行相关回归分析结果表明,渗透性抗冻剂的渗透压与孵化率呈显著的负相关(P<0.05),而非渗透性抗冻剂的渗透压与孵化率相关不显著。渗透性抗冻剂组的回归分析结果表明,二次方程的曲线拟合度最高,得到的回归方程分别为:Y10min = -2×10-8X2 10min - 6×10-5 X 10min + 1.5635 (R2 = 0.713),Y30min= 5×10-8X2 30min-0.0007 X 30min + 2.097(R2 = 0.681),Y1h = 7×10-8X2 1h-0.0008 X 1h+ 2.0397(R2= 0.725)。 在真鲷胚胎对抗冻剂耐受性实验的基础上,挑选五种抗冻剂--10%DMSO、5%甘油、10%甲醇、20%丙二醇、10%乙二醇,浸泡真鲷心跳期胚胎30min后,分别以超速(130℃/min)、快速(20℃/min)、慢速(3℃/min)的速度降温并使用低温显微镜进行观察,依次记录Toif(油球结冰)、Teif(胚胎外部结冰)、Tiif(胚胎内部结冰)等结冰点,Toif值在-9~-23℃之间;Teif值在-21~-35℃之间;Tiif值在-21~-52℃之间。结冰顺序为先油球结冰,然后胚胎外部结冰随之内部马上瞬间变黑形成内部冰晶。随着降温速度的提高,各结冰温度值显著下降。各抗冻剂之间的Teif及Tiif值不同,Toif值之间没有显著差异。对两种玻璃化冷冻方法进行模拟观察,发现胚胎冰晶形成的顺序与非玻璃化过程不同--先内部结冰然后逐渐蔓延至外部形成外部冰晶,而且模拟玻璃化的内部结冰温度Tiif值(-52.56℃)显著(P<0.05)低于使用低浓度的同种抗冻剂超速降温组的Tiif值(-40.11℃)。在快速及慢速降温组中,20%丙二醇组的Tiif要显著的低于其他组(P<0.05);在超速降温中,甲醇组的Tiif值要显著的低于其他组(P<0.05)。在Tiif小于30℃的实验组中获得形态完整胚胎的比例平均仅有30.77%;在Tiif大于30℃的实验组中获得形态完整胚胎的平均比例高达70.37%,模拟玻璃化组达到100%。各抗冻剂之间,复温后胚胎形态完整率10%甲醇组最高(77.78%);其次依次为10%乙二醇(66.67%)、20%丙二醇(55.56%)和10%DMSO(55.56%);5%甘油组最低(11.11%);推测甲醇的对胚胎的渗透效果要好于其他组。综上推测:使用丙二醇、甲醇作为抗冻剂以及玻璃化冷冻保存方法对真鲷心跳期胚胎超低温保存也许较为合适。 我们对低温保存的真鲷精子核DNA损伤进行了研究以期为下一步胚胎遗传物质稳定性研究提供参考依据。研究方法为单细胞凝胶电泳(SCGE),针对研究对象,在实验过程中对传统的碱性单细胞凝胶电泳在铺胶方法、电泳条件等进行了改进。对精子细胞进行预处理,在碱性电泳液中使核DNA双链解链变性后电泳,EB染色lOmin后,在荧光显微镜下观察,每次随机观察50个左右的核DNA。结果表明,对荧光显微镜下观察到的精子核按彗尾长度及荧光强度划分等级,出现损伤的精子核DNA的损伤程度主要为轻度损伤和中度损伤,很少见有完全损伤的真鲷精子核。经5%、10%、18%、20%、25%、30%DMSO冷冻保存后的精子彗星率分别为33.47% ± 8.95%; 35.91% ± 19.44%; 48.95% ± 8.90%; 43.33% ± 11.19%; 55.80% ± 38.94%。鲜精彗星率为31.43 % ± 2.68%。对比真鲷冷冻精液与新鲜精液的精子DNA的损伤状况,表明仅用30% DMSO冷冻精子DNA损伤状况与鲜精差异显著(P<0.05)。 综上所述,渗透性抗冻剂对胚胎的毒性与其渗透压值呈显著的负相关关系。丙二醇对真鲷心跳期胚胎毒性最小,甲醇较其他抗冻剂能更好的渗透入胚胎;玻璃化方法能显著降低Tiif值并能更好的保持超低温保存后胚胎的形态完整性,因此,使用丙二醇、甲醇作为抗冻剂以及玻璃化冷冻保存方法对真鲷心跳期胚胎超低温保存也许较为合适。常规使用的用于超低温保存真鲷精子的DMSO(浓度<15%)不会对精子核物质稳定性造成明显影响。由于胚胎较精子结构要复杂许多,对于真鲷胚胎损伤机理的研究还有大量工作可以开展。

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Practice Links is a free e-publication for practitioners working in Irish social services, voluntary and nongovernmental sectors. Practice Links was created to enable practitioners to keep up-to-date with new publications, electronic resources and conference opportunities. Issue 56 includes listings for upcoming conferences, resources, recent policy reports as well as reviews of publications.

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We present the results of BVRIZ photometry of 56 near-Earth objects (NEOs) obtained with the 1-m Jacobus Kapteyn telescope on La Palma during 2000 and 2001. Our sample includes many NEOs with particularly deep 1 - mum pyroxene/olivine absorption bands, similar to Q-type asteroids. We also classify three NEOs with particularly blue colors. No D-type asteroids were found, placing an upper limit of similar to2% on the fraction of the NEO population originating in the outer main belt or the Trojan clouds. The ratio of dark to bright objects in our sample was found to be 0.40, significantly higher than current theoretical predictions. As well as classifying the NEOs, we have investigated color trends with size and orbit. We see a general trend for larger silicate objects to have shallower absorption bands but find no significant difference in the distribution of taxonomic classes at small and large sizes. Our data clearly show that different taxonomic classes tend to occupy different regions of (a, e) space. By comparing our data with current model predictions for NEO dynamical evolution we see that Q- R-, and V-type NEOs tend to have orbits associated with "fast track" delivery from the main belt, whereas S-type NEOs tend to have orbits associated with "slow track" delivery. This outcome would be expected if space weathering occurs on time scales of >10(6) years. (C) 2003 Elsevier Science (USA). All rights reserved.

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El rol desempeñado por la opinión pública en el desarrollo de la política criminal actual justifica el incremento de investigaciones destinadas a evaluar las actitudes de los ciudadanos hacia el castigo. No obstante, los avances en este ámbito han sido limitados debido a la utilización de rudimentarios instrumentos de medida. Por ello, el presente trabajo tiene como propósito explorar el efecto que generan en la opinión ciudadana ciertas variables referidas al hecho delictivo y al infractor, precisando su contribución relativa y la interacción existente entre ellas. Para satisfacer este objetivo se recurrió a un diseño factorial de la encuesta, creando una población de 256 casos-escenario fruto de la combinación de cuatro factores: la edad del joven, su historial delictivo, el grado de implicación en el hecho y el tipo de delito cometido. Los mismos fueron distribuidos en grupos de ocho casos ordenados aleatoriamente y fueron suministrados a 32 sujetos. Posteriormente se aplicaron análisis de regresión logística binaria. Los resultados obtenidos revelan que la naturaleza violenta de los hechos, la implicación activa de los jóvenes y el historial delictivo son predictores importantes de las condenas punitivas. Sin embargo la edad, una variable fundamental en la configuración de la justicia juvenil, no resulta significativa. De este modo, el trabajo muestra el potencial explicativo de este conjunto de factores y debate sus implicaciones teóricas y metodológicas para la investigación futura en este terreno.

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Common Agricultural Policy - Clearance of EAGGF accounts - 1988 financial year

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We have established, through time correlated plasma emission and electrode and plasma potential measurements, that the near electrode emission observed in asymmetric capacitively coupled 13.56 MHz-driven hydrogen plasmas is caused by field reversal that leads to sheath collapse. Near-electrode emission has now been observed in Ar and He. The field reversal appears to be due to collision-induced electron drag. (C) 1997 American Institute of Physics.

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How can interlocking directorates cause financial instability for universal banks? A detailed history of the Rotterdamsche Bankvereeninging in the 1920s answers this question in a case study. This large commercial bank adopted a new German-style universal banking business model from the early 1910s, sharing directors with the firms it financed as a means of controlling its interests. Then, in 1924, it required assistance from the Dutch state in order to survive a bank run brought on by public concerns over its close ties with Müller & Co., a trading conglomerate that suffered badly in the economic downturn of the early 1920s. Using a new narrative history combined with an interpretive model, this article shows how the interlocking directorates between the bank and this major client, and in particular the direction of influence of these interlocks, resulted in a conflict of interest that could not be easily overcome.