上颌第一前磨牙三维模型的建立与研究

目的：建立上颌第一前磨牙三维模型,以辅助牙体解剖学数字化教学和指导临床根管治疗术。方法：对人离体上颌第一前磨牙通过ConebeamCT扫描,获得DICOM格式影像,将获得的影像定位后利用Mimicsl0．0三维重建软件采集牙釉质、牙本质及髓腔的点数据,然后将采集到的点数据导入到MagicslO．0软件进行面网格化,将网格化后的图像标本进行光滑处理后保存,再次利用MimicslO．0三维重建软件进行数据处理,最终获得清晰的牙体及根管系统三维立体图像。结果：准确的建立了包含牙釉质、牙本质、牙髓腔的三维立体模型。结论：本实验方法建立的上颌第一前磨牙的三维模型,具有极高的真实性和精确性,对辅助教学、指导临床根管治疗都具有重要意义。为牙体解剖教学和口腔临床应用提供了一种简捷而精确的建模方法。     

黄土丘陵区撂荒群落演替序列种根系对氮素施肥方式和水平的形态响应

采用盆栽试验,研究了黄土丘陵区撂荒群落演替序列种(即,黄土丘陵区摞荒群落演替主要阶段的优势种)根系对氮素施肥方式和水平的形态响应,对了解我国氮沉降增加背景下的群落生态效应及人为施肥干扰促进植被恢复具有较好的理论和实践意义。测试并分析了6个演替序列种在不同施氮方式(匀质和异质施氮)和水平(高、低和无氮对照)条件下植株个体生物量指标(地上及地下生物量和根冠比)、根系形态指标(根长、直径、表面积、比根长和比表面积)的变化及其差异显著性;并且利用根钻法和单样本T检验比较了异质施氮方式下施氮斑块与不施氮斑块根系形态指标的差异。结果表明:1)6种演替序列种地上、地下生物量和根冠比存在种间固有差别,施氮方式和水平整体上对三者无显著影响;施氮方式和植物种类对根冠比存在显著交互作用,说明个别种的根冠比对施氮方式响应明显,其中猪毛蒿根冠比在异质施氮方式下显著高于匀质施氮。2)6种演替序列种根系塑形指标包括比根长、比表面积和直径存在种间差别,并且施氮水平对比根长影响显著,高、低施氮水平下比根长都显著低于不施氮对照。3)狗尾草和铁杆蒿分别在异质高氮和异质低氮条件下施氮斑块根系生物量密度显著高于未施氮斑块;猪毛蒿在异质高氮条件下施氮斑块发生了更多的伸长生长,其根长、根表面积、比根长和比表面积在施氮斑块中的密度显著高于未施氮斑块;猪毛蒿和狗尾草在异质高氮条件下,以及白羊草在异质低氮条件下,其根系直径在施氮斑块显著小于未施氮斑块。从根系形态变化敏感性和施氮对促进植物生长来看,演替过程中演替序列种对施氮响应的敏感性总体上呈降低趋势,前期种对施氮响应更敏感,从施氮获利也更多,因而恢复前期进行人为干扰促进植被恢复效果也会更好。     

Various tolerances to arsenic trioxide between human cortical neurons and leukemic cells

Arsenic trioxide (As2O3) is very effective for treatment of acute promyelocytic leukaemia (APL) but little can pass through the blood-brain-barrier (BBB),which limits its use in the prevention and treatment of central nervous system leukaemia (CNSL). Before creating a non-invasive method to help As2O3 ’s access,the safe and effective therapeutic concentration of As2O3 in the CNS ought to be known. The changes of apoptosis biomarkers,[Ca2 ]i and PKC activity of both leukaemia cells and human cortical neurons,were monitored before and after being treated with As2O3 in vitro with laser confocal microscopy and Western blot. NSE concentration,the neuron invasive biomarker,was monitored by enzyme immunoassay (NSE-EIA). This study revealed that cortical neuron was more tolerable to As2O3 compared to NB4. 1.0 μmol / L As2O3 showed little influence on cortical neuron but effectively promoted apoptosis and induced differentiation of NB4.     

盐地碱蓬幼嫩花序的组织培养及植株再生

选用盐地碱蓬(Suaeda salsa)幼嫩花序为外植体, 建立了快速而高效的离体培养体系。在附加1.0mg.L-16-BA和0.4 mg.L-1 IAA的MS培养基上培养25天可诱导出不定芽, 诱导频率达到82.1%; 不定芽在此培养基上可快速扩增和长期继代培养。不定芽转至MS培养基中培养2~3周生根形成完整植株。     

白头翁的核型分析和有丝分裂的细胞学观察

对白头翁进行了核型分析发现,按Levan等(1964) 标准,核型公式为2n=16=10m+2sm+4st,为2A 核型按照(Stebbin)方法分为。白头翁染色体数目、核型和有丝分裂各时期的特征均为首次报道。     

The state transition mechanism - simply depending on light-on and -off in Spirulina platensis

The state transition in cyanobacteria is a long-discussed topic of how the photosynthetic machine regulates the excitation energy distribution in balance between the two photosystems. In the current work, whether the state transition is realized by "mobile phycobilisome (PBS)" or "energy spillover" has been clearly answered by monitoring the spectral responses of the intact cells of the cyanobacterium Spirulina platensis. Firstly, light-induced state transition depends completely on a movement of PBSs toward PSI or PSII while the redox-induced one on not only the "mobile PBS" but also an "energy spillover". Secondly, the "energy spillover" is triggered by dissociation of PSI trimers into the monomers which specially occurs under a case from light to dark, while the PSI monomers will re-aggregate into the trimers under a case from dark to light, i.e., the PSI oligomerization is reversibly regulated by light switch on and off. Thirdly, PSI oligomerization is regulated by the local H(+) concentration on the cytosol side of the thylakoid membranes, which in turn is regulated by light switch on and off. Fourthly, PSI oligomerization change is the only mechanism for the "energy spillover". Thus, it can be concluded that the "mobile PBS" is a common rule for light-induced state transition while the "energy spillover" is only a special case when dark condition is involved.     

Inactivation of Dicer1 has a severe cumulative impact on the formation of mature germ cells in mouse testes

Dicer1, an RNase III endonuclease, is indispensable for the maturation of miRNA and siRNA, which control gene expression through the RNAi pathway. The diverse functions of miRNA involving multiple developmental processes have been elucidated, but the role of Dicer1 in spermatogenesis is just beginning to be revealed. Mice lacking Dicer1 were reported to be embryonic lethal at E7.5. In the present study, mice with a Dicer1 conditional allele were crossed with Vasa-cre transgenic mice to delete Dicer1 as early as the prospermatogonia stage (at E15). At P40, seminiferous tubules of Dicer1 deficient mice showed several aberrant phenotypes. A large number of apoptotic germ cells were detected by the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, but several events in meiosis of spermatocytes appeared unaffected. The mutant mice were found to be sterile, likely due to the extensive decrease in number and morphological abnormalities of mature sperm in the epididymis, which, together with the numerous haploid cells in the testis, indicated a severely affected transition from round to functional elongated spermatozoa. Additionally, we found milder phenotypes when Dicer1 was inactivated in later stages of spermatogenesis in Stra8-cre and Pgk2-cre transgenic mice. In conclusion, our findings suggest that the loss of Dicer1 has a continuous and cumulative effect on the process of spermatogenesis and blocks the germ cells in the stage of round spermatids to a large extent, ultimately leading to the generation of abnormal sperm.     

1961-2010年中国春玉米潜在种植分布的年代际动态变化

基于构建的中国春玉米种植分布-气候关系模型,对1961-2010年春玉米潜在种植分布年代际变化进行了分析.结果表明:春玉米潜在可种植面积呈增加趋势;气候最适宜种植面积波动式增加,近10年达5.3×105 km2;适宜种植面积明显扩大,近50年增加约8.2×105 km2,且呈东扩趋势;潜在种植北界呈波动式北移,最大北抬达1.4个纬度.表明,气候变化有利于中国扩大春玉米种植,但一些地区可能受水分条件的限制.     

转基因水稻克螟稻2号定量检测用质粒标准分子研制及不确定度评价

转基因作物的食用安全和环境安全一直受到消费者与各国政府及相关机构人员高度重视。质粒标准分子是转基因核酸量值的载体,为实现转基因植物核酸量值准确性、可比性和有效性提供保障。描述了转基因水稻克螟稻2号质粒标准分子(pKMD2)的研制过程,包括质粒构建、特异性、均匀性、稳定性、可替代性和量值及不确定度评价等方面。量值结果表明pKMD2质粒标准分子所含两个基因片段比值为1.032,不确定度为0.032,可以替代基因组作为阳性标准品用于实验室质控、含量检测及贸易争端等领域。     

山东小麦地方品种资源铁和锌含量分析

利用等离子体发射光谱仪,对426份山东小麦地方品种资源进行了铁和锌微量元素含量的测定,摸清了山东省小麦地方品种资源铁和锌含量的分布情况。结果表明,山东小麦地方品种资源铁含量的分布范围为5.2～44.1mg/kg,锌含量的分布范围为6.2～50.4mg/kg。铁含量最高的种质是土耳其和落麦,分别为44.1mg/kg和41.8mg/kg;锌含量最高的种质是大青芒,为50.4mg/kg。利用这些铁锌含量高、子粒商品性及面制品口味好的小麦地方品种作育种亲本,对培育子粒中富含铁锌微量元素的高营养小麦新种质,具有十分重要的意义。