Influence of Intercalated Li on Electronic Structures and Optical Properties of V_2O_5

采用第一性原理局域密度近似法计算了V2O5的电子态密度和能带结构以及Li嵌入后对其电子结构和光学性质的影响。计算结果表明,V2O5是间接带隙半导体,Li的嵌入并没有改变其电子的跃迁方式。但Li的嵌入使得V2O5导带能量下移,禁带宽度减小,导带中原有的劈裂被分裂的能级填满;同时致使价带出现展宽。电子态密度计算结果表明Li的嵌入对临近的O和V的电子结构有较大的影响。Li2s电子的注入提高了V2O5的费米能级并导致其进入导带。由于价带中的电子只能跃迁到费米能级以上的导带空能级,这致使体系实际的光学带隙增大。同时随着Li注入量的进一步增加,价带的展宽更为明显,费米能级亦呈升高的趋势,使得光学带隙随着Li注入量的增加而增大。The density of states and band structures of α-V2O5 and Li-intercalated V2O5 (LixV2O5, x= 0.5 and 1.0) have been studied using a first-principles calculation based on density function theory with the local density approximation. The results indicate that V2O5 is an indirect-gap semiconductor; the intercalation of Li will not change its way of electron transition. While, the intercalation of Li lowers the energy of conduction band, and then narrows the band gap. At the same time, due to the intercalation of Li, the split-off in the conduction band of V2O5 disappears because of the split of conduction band. The Fermi level of LixV2O5 increases dramatically due to the electron transfer from Li 2s to the V2O5 host, which is probably the main reason why the optical band-gap augments with the Li intercalation.国家重点基础研究发展规划(001CB610505);; 国家自然科学基金(60376015,60336020);; 福建省青年人才创新基金(2005J005)资助项目~

TT病毒与肝炎关系的临床流行病学研究

目的　对闽南地区各种肝炎患者、健康体检者、义务献血员和肝癌患者共480例从临床流行病学角度探讨TT病毒(TTV)的致病性及其与各种肝炎的关系。方法　采用巢式PCR检测血清TTVDNA、ELISA检测血清抗HAVIgM、HBsAg、抗HBcIgM、抗HCVIgG、抗HEVIgG,用EPIINFO60软件进行统计分析。结果　480名研究对象中TTVDNA的总检出率为23.96%。各种肝炎患者的TTV总阳性率为2394%,肝癌患者的TTV阳性率为2069%,而健康者的TTV阳性率为2484%,义务献血员的阳性率为3000%,均未见明显差别。从临床类型看,急性肝炎、慢性肝炎和重症肝炎的TTV阳性率都在25%左右;从病原类型看,非甲～戊型肝炎的TTV阳性率为2619%,并未见与相应健康者的2523%阳性率的差别;除HCV由于感染率太低而无法分析外,HAV、HBV、HEV阳性肝炎患者间TTV的阳性率分别为2000%、2314%、2179%,未见TTV与这些已知肝炎病毒的明显相关。对一个时期内的全部135例住院肝炎患者及153名健康者进行肝炎病原分析,HAV、HBV、HEV在肝炎患者中的阳性率都要明显高于健康人(P=00142),而TTV在肝炎患者中的阳性率与健康人没有明显差别(P=06021);对病毒的单独致病性进行分析,HAV、HBV、HEV在非重叠感染的肝炎患者中的阳性率都要明显高于健康人(P=00037),而TTV在非甲～戊型肝炎患者中的

Elemene reversed the multidurg resistance of A549 /DDP lung cancer cells via mitochondrial apoptosis pathway

目的:探讨榄香烯乳(ElEMEnE,ElE)逆转人肺腺癌耐顺铂(CISPlATIn,ddP)细胞A549/ddP的耐药性及作用机制。方法:采用MTT法检测榄香烯乳单用的细胞毒作用及与ddP合用时耐药逆转作用。荧光探针JC-1结合激光共聚焦显微镜检测线粒体膜电位的变化。dCfH-dA荧光探针结合流式细胞仪检测细胞内活性氧(rEACTIVE OXygEn SPECIES,rOS)水平。用谷胱甘肽试剂盒结合分光光度法检测计算gSH/(gSSg+gSH)比值。蛋白质印迹法检测胞质中CyTO C、PrO-CASPASE-3、CASPASE-3和bCl-2家族蛋白表达情况。结果:不同浓度榄香烯乳抑制A549/ddP细胞株生长,呈时间-剂量依赖性效应,联合顺铂能提高A549/ddP细胞株对顺铂的敏感性而逆转耐药。不同浓度榄香烯乳联合顺铂使A549/ddP细胞株线粒体膜电位下降,rOS浓度增加,gSH/(gSSg+gSH)比值降低,上调胞质中CyTO C、CASPASE-3、bAd蛋白表达,下调PrO-CASPASE-3、bCl-2蛋白表达。结论:榄香烯乳逆转A549/ddP细胞株耐药性可能与其损伤线粒体膜,活化胞内氧化还原体系,诱导线粒体凋亡路径有关。Objective: To explore the mechanism that elemene( ELE) reversed the multidurg resistance( MDR)of A549 /DDP lung adenocarcinoma cell.Methods: MTT assay was used to determine the growth inhibition of human lung adenocarcinoma A549 /DDP cells in vitro.Mitochondrial membrane potential( MMP) was monitored by JC- 1fluorescence probe with laser confocal scanning microscopy,the intercellular reactive oxygen species( ROS) level was measured by 2',7'- dichlorfluorescein- diacetate( DCFH- DA) staining and flow cytometry and the ratio of GSH /( GSSG +GSH) was calculated according to detection results of GSH kit.The expression of Cytochrome C,Caspase-3 and the Bcl- 2 family proteins and in the case of cyclosporine A and DEVD- CHO,the expression of Caspase- 3expression were measured by Western blot.Results: MTT results showed that different concentrations ELE could inhibit the proliferation of A549 /DDP cells in a time- and dose- dependent manner.Intriguingly,ELE plus cisplatin enhanced the sensitivity of A549 /DDP cells to cisplatin and reversed A549 /DDP cells dury resistance.Different concentrations ELE decreased mitochondrial membrane potential,increased intracellular ROS concentration and decreased GSH /( GSSG + GSH) ratio of A549 /DDP cells in a time- and dose- dependent manner.Furthermore,the combination with both ELE and cisplatin also enhanced the protein expression of Cytoplasmic C,Caspase- 3 and Bad,and reduced the protein levels of Bcl- 2 and Pro- caspase- 3 in the cisplatin- resistant A549 /DDP cancer cells.Conclusion: ELE reversed the MDR of A549 /DDP cell line may demage mitochondrial membrane,active intracellular redox system and induce the mitochondrial apopotosis pathway.福建省自然科学基金面上项目(编号:2010D014

Preparation of the extracellular matrix of fish ordinary muscle for scanning electron microscopy

Aldehydes are the most common prefixation reagents to prepare specimens for scanning electron microscopy. In this study, scanning electron microscopic observations were made on the morphology of the extracellular matrix of carp ordinary muscle prepared using various prefixation reagents and fixation times. The structure of collagen fibers and its networks in extracellular matrix were more clear ly observed on day 5 than on day 2, when prefixation solution A (4% paraformaldehyde, 0.1 M sodium phosphate buffer, pH 7.2) was used, although honeycomb structure were not preserved during both periods. Prefixation of the extracellular matrix with solution B (2.5% glutaraldehyde, 0.1 M sodium phosphate buffer, pH 7.2) on days 2 and 5 preserved honeycomb structure with rough network, and some cellular debris remained. Prefixation of the extracellular matrix with solution C (2% paraformaldehyde, 2.5% glutaraldehyde, 0.1 M sodium phosphate buffer, pH 7.2) on day 5 preserved fine honeycomb structure with fine network without any cellular debris.These results suggested that prefixation for 5 days with solution C (2% paraformaldehyde, 2.5% glutaraldehyde, 0.1 M sodium phosphate buffer, pH 7.2) is the most suitable method of preparing extracellular matrix of fish ordinary muscle for scanning electron microscopy

Effects of Site-selective Ga-N Codoping on p-type Doping Efficiency of Wurtzite ZnO

采用第一性原理和密度泛函理论的方法,计算未掺杂、N单掺杂和Ga-N共掺杂纤锌矿结构ZnO的总能、电荷密度和能带结构。总能计算表明,Ga原子的共掺杂使总能极大地降低,从而显著提高杂质N原子在ZnO中的稳定性。电荷密度分布显示,总能的降低主要是Ga-N共掺杂后Ga原子的3d态和N原子的2p态电子之间的强杂化相互作用所致。特别是在Ga原子的负电荷和N原子的正电荷沿c轴排成一线的共掺杂构型中,较大的局域极化场的变化引起价带顶向禁带中的大分裂,降低了N受主的激活能,将空穴的浓度提高了三个量级,有效地提高p型掺杂效率。ZnO has become a promising material for ultraviolet light emitting diodes and lasers, transparent high power electronic devices dut to their wide direct band gap and large exciton binding energy. Undoped ZnO exhibits intrinsic n-type conductivity, and it is, therefore, difficult to achieve p-type ZnO. Among group-V dopants, N is considered to be a shallow p-type impurity; however, there are still many difficulties for using N as dopant. Recently, much effort has been devoted to fabricate p-type ZnO with codopants. So it is important to understand the codoping effect on electronic structures of wurtzite ZnO. N dopant stability and p-type doping efficiency of wurtzite ZnO were investigated by calculating the total energies, charge densities and band structures. The differences of total energy between the undoped configuration and N mono-doped, Ga-N codoped configuration Ⅰ and Ⅱ are ΔE_ T-N =1.22 eV, ΔE_ T-Ⅰ =-2.89 eV and ΔE_ T-Ⅱ =-2.84 eV, respectively. This shows that the N dopant stability is improved by Ga codopant. This result is attributable to the strong hybridization between the Ga 3d and N 2p states according to the induced charge density differences. Furthermore, the polarization is significantly changed in the Ga-N codoped configuration Ⅱ where the negative charges of the Ga atom and the positive charges of the N atom align along the c-axis. The energy band structures are thus clearly influenced. The twofold-degenerate Γ_ 5ν level of the top of the valence band for undoped ZnO splits into Γ_ 9ν and Γ~ (1) _ 7ν levels and shifts into the band gap to further separate with the non-degenerate Γ_ 1ν level (labelled as Γ~ (2) _ 7ν ). Then the activation energy of the N acceptor is lowered due to the splitting of the top of the valence band. Finally, according to the relationship between the hole concentration and the activation energy, the hole concentration under the modulation of configuration Ⅱ is enhanced more than three orders of magnitude.国家自然科学基金(60376015, 90206030, 60336020, 10134030);; 国家“973”计划(001CB610505);; 福建省科技计划(2004H054, E0410007)资助项

负载型钒钛脱硝催化剂酸化处理与性能

以商业TiO2为载体,采用浸渍法制备了V2O5-WO3-TiO2/SO24-催化剂,考察了硫酸酸化载体TiO2的顺序及硫酸酸化量对氨气选择性催化还原NO活性的影响,采用XRD、BET、FT-IR、TG-DTA、TPD等手段对催化剂进行了表征。BET表征结果表明,随着酸化处理的用酸量增大,催化剂表面积降低;但FT-IR、TG结果表明,增大酸化处理用硫酸量提高了硫酸根与钨之间的电子交互作用。程序升温的活性测试结果表明,硫酸酸化处理对催化剂活性具有促进作用,结合NH3-TPD表征证实了具有酸化处理程序制备的催化剂可以增强表面酸性位,从而使催化剂具有高活性

Stable Geometrical and Electronic Structrues of Wurzite ZnO(0001)-Zn and(000-1)-O Polar Surfaces

采用超高真空分子束外延和扫描隧道显微(STM)技术,对纤锌矿结构znO单晶(0001)-zn和(000-1)-O极性表面进行了STM形貌扫描和扫描隧道谱(STS)测量.STM表征结果显示,(0001)-zn极性表面形成了以单层高度交替出现的直线型和锯齿型台面的大表面纳米稳定结构,还通过形成(3x3)再构表面来稳定其表面.而(000-1)-O极性表面则形成了双层高度台面的表面稳定结构.STS测量结果表明,(0001)-zn极性表面内部偶极矩方向指向表面,而(000-1)-O极性表面内部偶极矩方向指向材料内部,导致两种极性表面能带的弯曲方向不同,最终引起两者导带底EC和价带顶EV能量位置的偏移.(0001)-zn和(000-1)-O极性表面I-V和dI-dV曲线的偏移体现了两种表面的不同极性和电子结构性质.Geometrical and electronic structures of wurtzite ZnO(0001)-Zn and(000-1)-O polar surfaces have been examined carefully by using an Omicron molecular beam epitaxy(MBE)and scanning tunneling microscopy(STM)combined system operated in ultra-high vacuum(UHV).STM measurements showed that(0001)-Zn polar surface tends to form the stable alternating straight and zigzag countertops with the double-layer step.In some areas there exist the(3×3)surface reconstruction.Different from the stabilization mechanism of(0001)-Zn polar surface,(000-1)-O polar surface can be stabilized by forming the double double-layer step countertops with the large flat surface.Furthermore,current-voltage properties measured by scanning tunneling spectroscopy(STS)indicate that,the conduction band bottomECand the valence band top EVof(000-1)-O polar surface shifts to the higher energy as compared with that of(0001)-Zn polar surface.The shifting of EC and EVis apparently attributed to different dipole moments of the(0001)-Zn and(000-1)-O polar surfaces and indicates the different polarity of two polar surfaces.国家自然科学基金(91321102;11304257;61227009); 福建省自然科学基金(2011J05006;2009J05149;2014J01026); 福建省教育厅资助项目(JA09146); 黄慧贞集美大学学科建设基金资助项目(ZC2010014); 集美大学科研启动金项目(ZQ2011008;ZQ2009004