单个人类端粒重复序列d(TTAGGG)对长链端粒DNA-d[AGGG(TTAGGG)_6]结构影响的研究（英文）

本文使用超速离心沉降速度法、聚丙烯酰胺凝胶电泳和圆二色光谱和紫外吸收检测熔融实验研究了长序列端粒DNA-d[AGGG(TTAGGG)_6](G_6-DNA)的结构以及单个重复序列DNA-d(TTAGGG)(G_(01)-DNA)对G_6-DNA结构的影响.结果表明G_6-DNA可以在水溶液中形成二聚体,并且G_(01)-DNA可以通过与G_6-DNA结合形成额外的G-四链体结构,从而改变单体与二聚体的平衡.然而,G_(01)-DNA对序列为d[AGGG(TTAGGG)_3](G_3-DNA)的结构没有影响.该研究为长序列单链端粒DNA的结构多样性提供了新的见解.     

层子模型中的(1/2)+重子的电磁性质和△(1236)的光生电生现象

本文利用层子模型的计算方法和文献[2]中的重子波函数,对1/2⁺重子的电磁性质和△(1236)的光生电生现象进行了讨论。文中利用重子的Bethe-Salpeter(以下简写B-S)方程取标量耦合和梯形近似,得到重子波函数中的两个不变函数成正比的结果,在此基础上把G_M^p(q²),μ_p和μ_A作为输入,可以较好地解释μ_p G_E^p     

SU(23)大统一模型

本文构造了一个SU(23)大统一模型,并以中间统一标度M_A为输入计算了大统一标度M_G的一些可能的值.在本模型中,重子数B在规范场和Higgs部分均守恒,因此并无质子衰变发生.我们还对能量在M_A处的规范玻色子按规范群SU(3)_c×SU(3)_L×U(1)_Y进行了分类.     

部分U(6) SU(3)的约化标量因子的代数表达式

利用不可约张量基方法和相互作用玻色子模型的解析波函数,计算得到了U(6) SU(3)简单的约化标量因子.通过应用递推关系,得到了U(6) SU(3)的[N_π×[N_p][N₁N₂]的部分约化标量因子的代数表达式.     

Hydrogen Bonding Character Between the Glycine and BF4-

在B3LYP/6-31+G^*水平上研究BF₄^-与甘氨酸间氢键作用特征,并在B3LYP/6-311++G^**水平上计算单点能. 对二聚物几何结构、能量、氢键成键特征进行分析. 分子中的原子拓扑分析表明氢键成键原子间存在(3,-1)关键点,电子密度和Laplacian量落在氢键范围内. 进一步对氢键形成导致H原子净电荷、偶极矩、能量及体积的改变进行系统分析.     

大统一对手征前子模型的限制

本文由WNW条件^[1]出发,分析了大统一对禁闭弱作用手征前子模型的限制.我们发现超色群不能是SU(N)群及SO(M)群,而半单群SU(N)×SO(M)及SU(N)×SU(M)作为超色群是可行的.通过重整化群计算,得到在合理的能标10^{14GeV≤Λ_u≤1019GeV及300GeV≤Λ_MC≤1TeV下,可能的候选者是:G_MC=SU(3)×SO(5)及G_U≥SU(11);G_MC=SU(3)×SU(2)及G_U≥SU(12).}     

反射式飞行时间质谱仪结合纳升电喷雾电离源研究金属簇合物

An experiment facility has been set up for the study of metal cluster compounds in our laboratory, which consists of a nano-electrospray ionization source, an ion transmission and focus system, and a reflectron time-of-flight mass spectrometer. Taking advantage of the nano-electrospray ionization source, polyvalent ions are usually produced in the “ionization” process and the obtained mass resolution of the equipment is over 8000. The molecular ion peaks of metal cluster compounds [Au₂₀(PPhpy₂)₁₀Cl₂](SbF₆)₄, where PPhpy₂=bis(2-pyridyl)phenylphosphine, and [Au₆Ag₂(C)L₆](BF₄)₄, where L=2-(diphenylphosphino)-5-methylpyridine, are distinguished in the respective mass spectrum, accompanied by some fragment ion peaks. In addition, the mass-to-charge ratios of the parent ions are determi-nated. Preliminary results suggest that the device is a powerful tool for the study of metal cluster compounds. It turns out that the information obtained by the instrumentation serves as an essential supplement to single crystal X-ray diffraction for structure characterization of metal cluster compounds.     

超薄栅超短沟LDD nMOSFET中栅电压对栅致漏极泄漏电流影响研究

本文研究了90nm CMOS工艺下栅氧化层厚度为1.4 nm沟道长度为100 nm的轻掺杂漏(LDD)nMOSFET栅电压V_G对栅致漏极泄漏 (GIDL)电流I_d的影响,发现不同V_G下ln (I_d/(V_DG-1.2))-1/(V_DG-1.2)曲线相比大尺寸厚栅器件时发生了分裂现象. 通过比较V_G变化下ln(I_d/(V_DG-1.2))的差值,得出V_G与这种分裂现象之间的作用机理,分裂现象的产生归因于V_G的改变影响了GIDL电流横向空穴隧穿部分所致. 随着|V_G|的变小,ln(I_d/(V_DG-1.2))曲线的斜率的绝对值变小.进一步发现不同V_G对应的ln (I_d/(V_DG-1.2))曲线的斜率c及截距d与V_G呈线性关系,c,d曲线的斜率分别为3.09和-0.77. c与d定量的体现了超薄栅超短沟器件中V_G对GIDL电流的影响,基于此,提出了一个引入V_G 影响的新GIDL电流关系式.     

IBM4中的强耦合SU(3)极限

将IBM推广应用于轻核时收IBM4.本文讨论了其中的下述群链.U(36)U₆(sd)×U₆(ST) SU₃(sd)×SU₃(S)×SU₃(T) SU₃(sdS)×SU₃(T)× O₃(J)× O₃(T)的约化、典型能说与E2跃迁,并用它对sd壳的核基态进行了分类.     

Mo(CO)6在清洁的和氧化的Si(111)表面上吸附的对比

采用高分辨电子能量损失谱对比研究Mo(CO)₆在清洁的、预吸附氧的和深度氧化的Si(111)表面上的吸附行为. 吸附Mo(CO)₆的C-O伸缩振动模式向低频方向移动,说明Mo(CO)₆与清洁Si(111)和SiO₂/Si(111)表面发生了不同的相互作用,前者较弱而后者较强. 与SiO₂/Si(111)表面的强相互作用可能引起Mo(CO)₆部分解离,形成部分分解的羰基钼物种.     

Analysis of Cation-Dependent DNA (G<Subscript>3</Subscript>T<Subscript>1</Subscript>)<Subscript>4</Subscript> Shape Change Using Fluorescence Correlation Spectroscopy

In G-rich DNA, it is well known that the form changes from single-strand DNA to G-quadruplex due to cations. In this study, we analyze the diffusion coefficient and fluorescence intensity obtained by fluorescence correlation spectroscopy for short G-rich DNA of the (G₃T₁)₄ sequence labeled as 5-Carboxytetramethylrhodamine (TAMRA) with variation of the K⁺ ion concentration. At a K⁺ ion concentration of more than 200 mM, the single-strand DNA was changed to the G-quadruplex. The size of the G-quadruplex decreased to 86% than the size of the single strand DNA at K⁺ ion concentration of 0 M. The size of the G-quadruplex and the fluorescence intensity of TAMRA attached to the DNA were constant with an increase in the K⁺ ion concentration between 200 and 800 mM. This means that the size of the DNA and the fluorescence intensity of the TAMRA are not affected by the K⁺ ion concentration at the G-quadruplex structure because the binding structure of DNA and TAMRA dye leads to stability at a concentration of less than 100 mM K⁺. Based on our short G-rich DNA results, longer G-rich DNA is analyzed for the diffusion coefficient of the DNA and the fluorescence intensity variation of fluorescence dye attached to the DNA.     

Repetitive DNAs in the slug Milax nigricans: association of ribosomal (18S-28S and 5S rDNA) and (TTAGGG)n telomeric sequences in the slug M. nigricans (Mollusca: Gastropoda: Pulmonata)

Spermatocyte chromosomes of the slug Milax nigricans (Mollusca: Gastropoda: Pulmonata) were studied using silver staining (Ag-NOR) and fluorescent in situ hybridization (FISH) with four repetitive DNA probes [18S rDNA, 5S rDNA, (TTAGGG)n and (GATA)n]. Silver impregnation was inadequate to localize the chromosome sites of nucleolus organizer regions (NORs) since no silver dots occurred on the chromosomes at spermatogonial metaphase and a diffuse silver stainability could be observed on the bivalents at metaphase-I. Unlike silver staining, single-colour rDNA FISH consistently mapped major ribosomal sites (18S-28S rDNA) on two small-sized chromosomes in spermatogonial cells and on the correspondent metaphase-I bivalent in spermatocytes. While telomeric (TTAGGG)n sequence hybridized to all chromosomes, (GATA)n probe localized abundant hybridization sites, dispersed throughout the genome. Simultaneous double-colour FISH demonstrated a close chromosomal association of 18S-28S rDNA, 5S rDNA and (TTAGGG)n.     

Calculation of the nuclear vertex constant (asymptotic normalization coefficient) for the virtual decay 6Li → α + d on the basis of the three-body model and application of the result in describing the astrophysical nuclear reaction d(α, γ)6Li at ultralow energies

Within the (α, n, p) three-body model, the s-wave ⁶Li → α + d vertex constant G ₀₁ and the asymptotic normalization coefficient C ₀₁ (these two quantities are proportional to each other) for the wave function describing the ⁶Li nucleus in the α + d channel are calculated by solving Faddeev equations for various sets of nucleon-nucleon and α N potentials. The resulting values of G ₀₁ and C ₀₁ are used to calculate the astrophysical factor S(E) for the radiative-capture reaction d(α, γ)⁶Li at energies in the range E = 0–600 keV. The calculated values of G ₀₁ and C ₀₁ appear to be sensitive to the form of the pair potentials used. It is shown that, upon correctly taking into account the contributions of the E2 and E1 multipolarities, the values of S(E) in the region E < 150 keV are determined primarily by the values of C ₀₁ and of the ⁶Li binding energy in the α + d channel.     

The interaction of DNA with organotin(IV) salts and complexes

Ethanol solutions of Alk _n SnCl_4?n (Alk = Me, Et; n = 1–3) added to aqueous calf thymus DNA provoke DNA condensation (even in the presence of added cysteine) possibly through charge neutralization of DNA phosphodiesters by organotin(IV) cations. The structures of tin bonding environments in binary and ternary condensed systems organotin(IV)-DNA and ligand-organotin(IV)-DNA are determined through point-charge model treatment of the ¹¹⁹Sn Mössbauer parameter Δ, while the possible interchain interaction DNA-tin is inferred from the dynamics of ¹¹⁹Sn nuclei through vtMs.     

Analysis of G‐quadruplex conformations using Raman and polarized Raman spectroscopy

G‐quadruplexes (G4s) are four‐stranded DNA structures formed within nucleic acid sequences that are rich in guanines. G4 formation within DNA strands is believed to have significant biological relevance for the control of cell replication and gene expression. Therefore, the development and validation of experimental techniques that can easily and reliably characterize G4 structures under biologically relevant measurement conditions, like Raman spectroscopy, are desirable for G4‐targeted structure based drug design. Here we report Raman and polarized Raman studies of solutions of three oligonucleotides, thrombin binding aptamer (TBA) 5′‐GGTTGGTGTGGTTGG‐3′, human telomeric (HT) 5′‐(TTAGGG)₄‐3′, and a modified c‐Myc NHE‐III₁ sequence (MycL1) 5′‐TGAGGGTGGGTAGGGTGGGTAA‐3′, which were previously reported to form four distinct intramolecular G4 structures in the presence of Na⁺ or K⁺, as determined by NMR. Our results support the previously proposed antiparallel (TBA), antiparallel and hybrid (HT), and parallel with double‐chain reversal (DCR) loop (MycL1) structures. Large sample‐dependent variations in the intensity of bands associated with deoxyribose backbone modes in the 840–930 cm⁻¹ and 1420–1460 cm⁻¹ spectral regions were observed. Most notably, a highly polarized deoxyribose ring symmetric stretch (~930 cm⁻¹) appeared strongly in the solution spectra for HT and TBA, but was very weak or absent in the solution spectrum for MycL1 and the drop deposition (dried sample) spectra for all three oligonucleotides. It is hypothesized that the intensity of this band is likely controlled by furanose ring structure uniformity and/or solvent accessibility to certain nucleotide binding sites. Raman depolarization ratios measured for the G4s in solution were generally very similar to those previously reported for canonical B DNA, with the possible exception of base ring modes that consistently yielded slightly lower depolarization ratios for G4s compared to B DNA. The results further underscore the utility of Raman and polarized Raman spectroscopy for G4 structure elucidation under biologically relevant solution conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

KTa1-xNbxO3晶体生长固/液边界层结构的微区研究

测量了KTa_1－xNb_xO₃(KTN)晶体在常温和高温下的Raman光谱;实时测量了晶体生长过程中,固/液边界层内以及边界层两侧的晶体和熔体的高温显微Raman光谱.通过光谱分析获得了KTN晶体生长固/液边界层内的结构特征,以及晶体生长基元从熔体结构经边界层过渡到晶体结构的变化规律.研究表明,KTN熔体中的 结构基团进入到生长边界层后逐步转化为 八面体结构基团,已具有KTN单胞的一些特征.进而讨论了以 八     

Investigation of thionin-DNA interaction by satellite hole spectroscopy

The interactions of the two tautomers of thionin dye with DNA have been investigated by using satellite hole burning spectroscopy. Similar features in the absorption and satellite hole spectra of thionin in the presence of calf thymus (CT) DNA and polynucleotides [d(GC)₆]₂ (GC) suggested that thionin preferentially binds to GC rather than polynucleotides [d(AT)₆]₂ (AT). Different binding effects of the two tautomers to DNA could be observed. While the imino form fully intercalates into the DNA base pairs, the amino form is only partially intercalated. In addition, a broad hole associated with an antihole appeared in the presence of DNA, particularly in GC base pairs. The coincidence of the antihole with the absorption band of the amino form showed that the amino form is the photoproduct of the imino form. An increase in intensity of the broad hole and its antihole and the loss of nonresonant hole intensity upon interaction with CT DNA could be described by rapid ground state recovery resulting from fast charge transfer between the intercalated thionin and a guanine base quenching the internal conversion.     

Deep-Red Phosphorescent Iridium(III) Complexes Containing 1-(Benzo[b] Thiophen-2-yl) Isoquinoline Ligand: Synthesis,Photophysical and Electrochemical Properties and DFT Calculations

Four new bis-cyclometalated iridium(III) complexes, [Ir(btq) ₂phen] [PF₆] (3a), [Ir(btq) ₂bpy] [PF₆] (3b), [Ir(btq) ₂dtbipy] [PF₆] (3c) and [Ir(btq) ₂pic] (3d) (btq?=?1-(benzo[b] thiophen-2-yl) isoquinoline, phen?=?1,10-phenanthroline, bpy?=?2,2′-bipyridine, dtbipy?=?4,4′-di-tert-butyl-2,2′-bipyridine, pic?=?picolinic acid) have been synthesized and fully characterized. The crystal structure of 3a has been determined by X-ray analysis. The photophysical and electrochemical properties of these new complexes 3a???3d have been studied. The photoluminescence spectra of all Ir(III) complexes exhibit deep-red emission maxima at 682, 682, 683 and 698 nm, respectively. The most representative molecular orbital energy-level diagrams and the lowest energy electronic transitions of 3a???3d have been calculated with density functional theory (DFT) and time-dependent DFT (TD???DFT). The results show that the pic ancillary ligand of complex 3d influences the absorption and emission energies with a further red-shift relative to other three complexes 3a???3c.     

Formation of a G-quadruplex structure from human mature miR-5196-5p

Some human mature microRNAs are featured of G_≥2N_xG_≥2N_yG_≥2N_zG_≥2 sequences. In this study, a human mature microRNA, miR-5196-5p, was selected as an example to probe the secondary structure of G-rich microRNA. Our results have confirmed that miR-5196-5p could form a stable G-quadruplex structure with three G-quartets and three double-chain-reversal loops by electrospray ionization mass spectrometry, nuclear magnetic resonance, circular dichroism spectroscopy, and molecular dynamics simulation. Our study showed the prevalence of G-rich microRNAs in Homo sapiens, rat, mouse, and Arabidopsis thaliana, and they have great potential to fold into intramolecular G-quadruplexes which may serve as new targets for the regulatory function of G-rich mature microRNAs.     

Co(II) Complexes of4-((3-ethoxy-2-hydroxybenzylidene)amino)-N-(thiazol-2-yl)benzenesulphonamide and 4-((pyridin-2-ylmethylene)amino)-N-(thiazol-2-tl)benzenesulfonamide: Synthesis,Fluorescence Properties and Anticancer Activity

Two new Co(II) complexes of 4-((3-ethoxy-2-hydroxybenzylidene)amino)-N-(thiazol-2-yl)benzenesulphonamide and 4-((pyridin-2-ylmethylene)amino)-N-(thiazol-2-yl)benzene sulfonamide were synthesised. The structure of the complexes was identified by elemental analysis, FT-IR, electronic, EI mass, Powder XRD spectra and magnetic moment. The TG and DTA patterns of the complexes were supported the structures. The fluorescence quenching of these complexes with alizarin dye were premeditated and the free energy change (?G_et) for electron transfer process was designed by Rehm-Weller equation. The [Co(L₁-H)₂(H₂O)₂] and [Co(L₂)₂(H₂O)₂].2H₂O were submitted for in vitro cytotoxicity studies in human breast cancer cell line (MCF 7).