电磁刺激对成骨样细胞UMR-106 DNA合成的作用

为了从细胞水平研究低频电磁场影响成骨样细胞增殖的有效物理参数 ,并为其作用机制的解释提供依据 ,论文就几种类型电磁场对成骨样细胞 UMR- 10 6DNA合成的作用进行了一系列实验 ,通过 3 H-脱氧胸苷掺入检测 DNA合成的改变 ,发现特定频率、场强 (或磁感应强度 )组合的电磁场 (脉宽 0 .2 m s,10 V/cm,12 5 Hz附近的脉冲电场 ;1V/cm,10 Hz附近的交变电场 ;0 .5 m T,5 Hz附近的交变磁场 )能促进细胞 DNA合成水平显著提高 ,表明刺激骨细胞生长的电磁场无需复杂的波形。场强对 DNA合成有重要作用 ,只有在合适的场强范围内 ,一定频率的电磁场对细胞才有刺激作用。交变磁场所诱导的电场很微弱 ,表明磁场不只是通过诱导电场发挥作用的 ,研究磁场对细胞的作用应考虑包括磁场直接作用等全部可能的机制。     

6B1细胞的低频弱电磁场效应研究

以小鼠６Ｂ１骨髓瘤细胞为效应靶细胞,采用细胞化学（ＭＴＴ）,免疫酶标（ＥＬＩＳＡ）等方法,研究了低频弱电磁场对６Ｂ１细胞代谢的影响。结果表明：（１）１ｍＶ／ｃｍ的低频电场（１０～１００Ｈｚ）对６Ｂ１细胞的增殖无明显作用,而１ｍＶ／ｃｍ,５０Ｈｚ电场对６Ｂ１细胞乙肝表面抗体的分泌有显著促进,提示在此条件下电场对６Ｂ１细胞膜的外侧存在某种特异性作用;（２）０．８Ｔ、３０Ｈｚ的弱磁场对６Ｂ１细胞的增殖有     

极低频电磁场对小鼠脑组织脂质过氧化及白细胞的影响

在小鼠上观测了50Hz、4mT电磁场间断暴露后脑组织超氧化物歧化酶（SOD）活力和丙二醛（MDA）含量以及血液白细胞总数和分类的变化。结果表明：SOD活力在暴露10天和20天时下降显著;MDA含量在暴露1天和10天时明显下降,但在20天时显著升高。血液白细胞数在暴露1天和20天时均显著减少,但在10天时显著增多;嗜中性粒细胞百分率在暴露1天和20天时显著上升,与此同时淋巴百分率显著下降。提示在本实验条件下,50Hz电磁场可加剧脑组织的脂质过氧化,改变血液白细胞组分的计数;这些变化与磁场暴露的持续时间有关,类似于一种应激效应。     

S_2Cl_2分子电子结构外电场特性理论研究

采用B3LYP/aug-cc-pVTZ方法研究了不同外电场对S2Cl2分子基态结构参数键长、键角、二面角、偶极矩及分子振动光谱的影响规律.结果表明外电场电场强度增大,相应SS键长逐渐变长,SCl键长逐渐变短,分子极性增强.外电场对分子不同振动模式的振动频率数值、强度影响存在差异.因而可利用外电场影响分子的特定振动模式以获得特定的振动光谱.     

Luminescence Property of Phosphor Gd 3Ga 5O 12 :Ag

采取在不同的温度下烧结不同的时间方法制备了一种新型的兰色发学材料,用Ｘ光衍射对材料的结构进行了分析．并利用电子束蒸发的方法制备该材料的薄膜电臻发光器件．对该器件进行了光致发光,电致发光,亮度电压等发光性质进行了测试．得出器件亮度大约为２尼特     

Roles of E. coli DNA polymerases IV and V in lesion-targeted and untargeted SOS mutagenesis

The expression of the Escherichia coli DNA polymerases pol V (UmuD'2C complex) and pol IV (DinB) increases in response to DNA damage. The induction of pol V is accompanied by a substantial increase in mutations targeted at DNA template lesions in a process called SOS-induced error-prone repair. Here we show that the common DNA template lesions, TT (6-4) photoproducts, TT cis-syn photodimers and abasic sites, are efficiently bypassed within 30 seconds by pol V in the presence of activated RecA protein (RecA*), single-stranded binding protein (SSB) and pol III's processivity beta,gamma-complex. There is no detectable bypass by either pol IV or pol III on this time scale. A mutagenic 'signature' for pol V is its incorporation of guanine opposite the 3'-thymine of a TT (6-4) photoproduct, in agreement with mutational spectra. In contrast, pol III and pol IV incorporate adenine almost exclusively. When copying undamaged DNA, pol V exhibits low fidelity with error rates of around 10(-3) to 10(-4), with pol IV being 5- to 10-fold more accurate. The effects of RecA protein on pol V, and beta,gamma-complex on pol IV, cause a 15,000- and 3,000-fold increase in DNA synthesis efficiency, respectively. However, both polymerases exhibit low processivity, adding 6 to 8 nucleotides before dissociating. Lesion bypass by pol V does not require beta,gamma-complex in the presence of non-hydrolysable ATPgammaS, indicating that an intact RecA filament may be required for translesion synthesis.     

电脉冲孕育处理对Al-5%Cu-0.8%Mn合金组织及性能的影响

通过凝固组织观察、力学性能测试、断口分析等实验,研究了不同电脉冲孕育处理对Al-5%Cu-0.8%Mn合金组织和性能的影响.实验结果表明,不同电脉冲处理参数均使Al-5%Cu-0.8%Mn合金凝固组织细化,单位面积晶粒数提高2倍以上;合金力学性能较未处理试样明显改善,抗拉强度增加了21%～35%,伸长率提高1.8～2.5倍;且当脉冲电压500V、时间30s、频率3Hz时,合金的凝固组织细化效果最好,力学性能最佳.     

太行山猕猴电刺激采精试验

作者采用阴茎电极器法对太行山猕猴进行了电刺激采精试验．太行山猕猴采精刺激参数平均值为：电压２２～２８Ｖ；频率３０Ｈｚ；波宽１０ｍｓ．平均刺激８．４ｓ开始排精，平均采精量３．９５ｇ／次．比较发现，阴茎电极器法采精量明显高于直肠探子法．     

外场下SnO分子结构和特性研究

对Ｓｎ原子采用ＳＤＢ-ｃｃ-ｐＶＴＺ基组,Ｏ原子采用 ６-３１１＋＋Ｇ基组,利用密度泛函中的 Ｂ３Ｐ８６方法对 ＳｎＯ分子的基态结构进行了优化计算,并研究了外场对 ＳｎＯ基态分子的键长、总能、电荷布居分布、能级分布、电偶极矩、谐振频率和红外谱强度的影响。并利用杂化密度泛函理论（ＣＩＳ ＤＦＴ）方法研究了外电场对 ＳｎＯ分子由基态到前 ６个单重激发态跃迁规律的影响。结果表明,在所加电场范围内,随着正向电场 Ｆ的逐渐增大,基态分子的键长 Ｒｅ先减小后增大,在 Ｆ＝００４ａ．ｕ．时取得最小值 ０１７９６ｎｍ;总能先增大后减小,其在 Ｆ＝００３ａ．ｕ．时取得最大值 －２１４４８３９６ｅＶ;电偶极矩则先减小后增大,在 Ｆ＝００３ａ．ｕ．时取得最小值 ０２１２４Ｄｅｂｙｅ;ＳｎＯ基态分子的最高已占据轨道（ＨＯＭＯ）能量 ＥＨ和谐振频率逐渐增大;红外光谱强度、分子的最低未占空轨道（ＬＵＭＯ）能量ＥＬ和能隙 Ｅｇ则逐渐减小。外电场的大小与方向对跃迁电偶极矩、跃迁波长、激发能和振子强度均有很大影响。     

介质阻挡放电功率测量及各参量变化规律

通过建立介质阻挡放电试验系统,采用Q-V Lissajous图形法研究了激励电压V、激励频率.f对介质阻挡放电电学参量的影响.试验结果表明:提高V,f可有效提高介质阻挡放电的放电功率P、电荷传输量Q;当介质阻挡放电装置结构参数确定后,V,f对等效总电容C的影响不大,电介质层等效电容Cd随V,f的增大而增大,放电气隙等效电容Vg随V,f的增大而略有下降;气隙有效电场强度Eg随V的升高而增大,f对Eg的影响不大;该介质阻挡放电产生的平均电子能量较高,可用于臭氧发生器等设备.     

Molecular dynamics simulation study on behaviors of liquid 1,2-dichloroethane under external electric fields

Molecular dynamics simulation was carried out to study the behavior of liquid 1,2-dichloroethane molecules under external electric fields including direct current field, alternating current field and positive-half-period cosin field. The maximum applied field strength was 10(8) V/m, the maximum frequency of the alternating current field and that of the positive-half-period cosine field was 10(12) Hz. The simulation revealed that the field type and field strength act on the population of the molecular configuration. In the strong direct current field, all trans forms converted completely into gauche forms. Order parameter and the correlation of the system torsion angle were also investigated. The results suggested that these two dynamical parameters depended also on the field type and the field strength. The maximum of order parameter was found to be at 0.6 in the strong direct current field.     

生物细胞在极低频电磁场中的效应

探讨极低频电磁场对洋葱根尖细胞及人肺成纤维细胞生物学特性的影响.对生长发育过程中洋葱根和体外培养的人肺成纤维细胞进行50 Hz,3 mT极低频电磁场(ELFMFS)处理,对洋葱根的外部形态及细胞有丝分裂指数、染色体形态等进行观察分析,对人肺成纤维细胞进行增殖量比较及凋亡分析.结果表明:50 Hz,3 mT ELFMFS在20 ℃时对洋葱根的生长量无明显影响,但在30 ℃下对洋葱根的生长起抑制作用且可导致根生长异常;正常培养条件下,ELFMFS照射组人肺成纤维细胞生长受到抑制,有细胞凋亡发生.ELFMFS与温度的叠加效应(50 Hz,3 mT,30 ℃)可对洋葱根的生长及根尖细胞的增殖产生重要作用,ELFMFS对人肺成纤维细胞的生长起抑制作用并可引起细胞凋亡.     

RecA acts in trans to allow replication of damaged DNA by DNA polymerase V

The DNA polymerase V (pol V) and RecA proteins are essential components of a mutagenic translesion synthesis pathway in Escherichia coli designed to cope with DNA damage. Previously, it has been assumed that RecA binds to the DNA template strand being copied. Here we show, however, that pol-V-catalysed translesion synthesis, in the presence or absence of the beta-processivity-clamp, occurs only when RecA nucleoprotein filaments assemble or RecA protomers bind on separate single-stranded (ss)DNA molecules in trans. A 3'-proximal RecA filament end on trans DNA is essential for stimulation; however, synthesis is strengthened by further pol V-RecA interactions occurring elsewhere along a trans nucleoprotein filament. We suggest that trans-stimulation of pol V by RecA bound to ssDNA reflects a distinctive regulatory mechanism of mutation that resolves the paradox of RecA filaments assembled in cis on a damaged template strand obstructing translesion DNA synthesis despite the absolute requirement of RecA for SOS mutagenesis.     

极低频磁场对两种瘤细胞代谢活力的影响

采用ＭＴＴ 比色分析法研究极低频磁场对ＳＨ－ＳＹ５Ｙ 和ＰＣ－１２ 瘤细胞代谢活力的影响．实验结果表明：在相同参数的磁场作用下,不同类型细胞代谢活力的变化不同;ＳＨ－ＳＹ５Ｙ 和ＰＣ－１２ 两种瘤细胞都对磁场振幅和频率敏感,在某些磁场参数下磁场照射能够使细胞代谢活力有明显降低或升高;振幅和频率不同的磁场,即使都对细胞代谢活力有影响,磁场作用的大小也存在差异．本研究证实极低频磁场在某些参数下可能抑制或增强瘤细胞线粒体的呼吸作用     

Superconductor-insulator transition in La2 - xSrxCuO4 at the pair quantum resistance

High-temperature superconductivity in copper oxides arises when a parent insulator compound is doped beyond some critical concentration; what exactly happens at this superconductor-insulator transition is a key open question. The cleanest approach is to tune the carrier density using the electric field effect; for example, it was learned in this way that weak electron localization transforms superconducting SrTiO(3) into a Fermi-glass insulator. But in the copper oxides this has been a long-standing technical challenge, because perfect ultrathin films and huge local fields (>10(9)?V?m(-1)) are needed. Recently, such fields have been obtained using electrolytes or ionic liquids in the electric double-layer transistor configuration. Here we report synthesis of epitaxial films of La(2-?x)Sr(x)CuO(4) that are one unit cell thick, and fabrication of double-layer transistors. Very large fields and induced changes in surface carrier density enable shifts in the critical temperature by up to 30?K. Hundreds of resistance versus temperature and carrier density curves were recorded and shown to collapse onto a single function, as predicted for a two-dimensional superconductor-insulator transition. The observed critical resistance is precisely the quantum resistance for pairs, R(Q) = h/(2e) = 6.45?kΩ, suggestive of a phase transition driven by quantum phase fluctuations, and Cooper pair (de)localization.     

交变电场频率对电凝并影响的理论及实验研究

根据碰撞理论,推导出偶极行电尘粒在突变电场中的电凝并系数,并利用Williams求声凝并的方法,将其简化。电凝并除烟实验在2,4,6Hz三种频率下进行,结果表明：三种频率下的除尘效率比较接近,但频率为6Hz时除尘效果较好。     

脉冲电场对好氧反硝化细菌生长代谢的影响

将脉冲电场技术应用于硝酸盐废水的好氧反硝化处理.通过比较不同脉冲电场强度、脉冲频率、极板间距和接种量等因素作用下好氧反硝化细菌生长代谢的变化情况,确定了脉冲电场处理的最佳工艺参数.结果表明,在电场强度为0.8V·cm^-1,频率为1000Hz,极板间距为5cm,接种量为5%的最佳试验条件下,经脉冲电场处理的好氧反硝化细菌Pseudomonas putida W207-14仅24h其在600nm波长下的细胞光密度(OD600)、化学需氧量(COD)和硝态氮(NO^-₃-N)的去除率均达到最大值,分别为1.926±0.04,(97.67±1.12)%和(90.34±0.73)%.与未处理的好氧反硝化细菌相比,在生长时间大幅缩短的同时,其硝酸盐去除速率提高了115.76%.     

Spatial measurement on the evidence of ionospheric Alfvén resonator

Using the data of ULF/ELF electric and magnetic wave field measured on board AUREOL-3 satellite, by the high resolution spectral analyses, one obtained for the first time the spatial measurement on the evidence of ionospheric alfvén resonator. The result of the measurement indicates that there are 7. 8 Hz for fundamental frequency, 14 Hz for second resonant frequency in the electric field component, and also the spectral resonance structure, but not in the magnetic vertical component for the magnetic field components.     

PuO3分子激发态的外场效应

 采用密度泛函(DFT)方法B3LYP/Gen,在Pu为相对论有效原子实势(RECP)基组、O为6-311+G*基组水平上优化得到了分子轴方向不同电偶极场（0.005～0.005a.u）作用下,PuO3的基态电子状态为C 2v(7B-2)。在优化构型下用同样的基组采用含时密度泛函(TDDFT)方法(TD-B3LYP)研究了同样外电场条件下对PuO3的激发能和振子强度的影响。计算结果表明,激发能随电场强度增加而减小,表明在外电场作用下电子容易激发,且对电场方向的依赖呈现近似对称性,满足Grozema关系。PuO3的前5个激发态电子跃迁光谱波长为900.2～2063.3 nm,属于红外、远红外光谱,这是钚原子的奇异特征。电场对振子强度的影响仍满足跃迁选择定则。