CO2 laser-assisted preparation of transparent Eu2Ti2O7 thin films

We present a laser-assisted preparation of transparent europium-titanate Eu₂Ti₂O₇ thin films with tailored structural and optical properties. We have evaluated the effects of the irradiation time on the structural and the optical properties of the films. This approach allows the preparation of nanocrystalline crack-free films and micro patterns. The amorphous thin films were prepared by a sol-gel method. The films were annealed by a CO₂ laser beam for various time intervals. The laser irradiation induced a crystallization process that resulted in the formation of Eu₂Ti₂O₇ nanocrystals. The nanocrystals regularly grew with increasing irradiation time reaching the size from 25?nm to 45?nm. A film of a thickness 480?nm exhibited an optical transmission of 91.9% that is close to the maximal theoretical limit. The film's refractive index at 632?nm was 2.26. A micrometric pattern was prepared by a direct laser writing followed by a wet chemical etching. Feasibility of the demonstrated approach, together with the high film's quality, and europium-titanate chemical resistivity open up many opportunities for advanced applications. The approach can be used for a preparation of protective coatings and integrated photonic devices such as planar optical waveguides and couplers.     

Protein structure alignment by incremental combinatorial extension (CE) of the optimal path

A new algorithm is reported which builds an alignment between two proteinstructures. The algorithm involves a combinatorial extension (CE) of analignment path defined by aligned fragment pairs (AFPs) rather than themore conventional techniques using dynamic programming and Monte Carlooptimization. AFPs, as the name suggests, are pairs of fragments, one fromeach protein, which confer structure similarity. AFPs are based on localgeometry, rather than global features such as orientation of secondarystructures and overall topology. Combinations of AFPs that representpossible continuous alignment paths are selectively extended or discardedthereby leading to a single optimal alignment. The algorithm is fast andaccurate in finding an optimal structure alignment and hence suitable fordatabase scanning and detailed analysis of large protein families. Themethod has been tested and compared with results from Dali and VAST using arepresentative sample of similar structures. Several new structuralsimilarities not detected by these other methods are reported. Specificone-on-one alignments and searches against all structures as found in theProtein Data Bank (PDB) can be performed via the Web athttp://cl.sdsc.edu/ce.html.     

间规1,2—聚丁二烯合成的实验室研究

报道了使用Ｃｏ－Ａｌ－Ｐ－Ｈ２Ｏ催化体系实验室合成间规１，２－取丁二烯的研究结果，详细讨论了催化组分的加料顺序，老化条件及聚合工艺条件对聚合反应的影响，在此基础上得到最佳工艺条件，进行了模试放大，所得聚合物的基本性能与ＪＳＲ ＲＢ８２０相近。     

Nitric oxide synthase in neuroepithelial brain tumors

Immunohistochemical investigation of NO-synthase in brain astrocytic tumors revealed intense reaction in many tumor cells as well as direct correlation in the intensity of reaction and the degree of tumor anaplasia. Grade I astrocytomas did not show immunoreactivity in contrast to high anaplastic tumors where many cells had positive reaction with a different degree of intensity. Positive immunoreaction was shown in many giant cells. Small cell glioblastomas and oligodendrogliomas were immunonegative. There was a direct correlation between NO-synthase expression and glial fibrillar acidic protein.     

Interaction between the DRD4 VNTR polymorphism and proximal and distal environments in alcohol dependence during emerging and young adulthood.

The manifestation of alcohol dependence at different developmental stages may be associated with different genetic and environmental factors. Taking a developmental approach, we characterized interaction between the dopamine receptor 4 variable number tandem repeat (DRD4 VNTR) polymorphism and developmentally specific environmental factors (childhood adversity, college/Greek organization involvement, and delayed adult role transition) on alcohol dependence during emerging and young adulthood. Prospective data were obtained from a cohort of 234 White individuals (56% women, 44% men) who were followed up at ages 18 through 34. A longitudinal hierarchical factor model was estimated to model a traitlike persistent alcohol dependence factor throughout emerging and young adulthood and 2 residual statelike alcohol dependence factors limited to emerging adulthood and young adulthood, respectively. We accounted for those alcohol dependence factors by modeling 3 two-way interaction effects between the DRD4 VNTR polymorphism and the 3 developmentally specific environment factors. Carriers of the DRD4 long allele showed greater susceptibility to environmental effects; they showed more persistent symptoms of alcohol dependence as childhood adversity increased and more alcohol dependence symptoms limited to emerging adulthood as college/Greek organization involvement increased. Alcohol dependence among noncarriers of the long allele, however, did not differ as a function of those environments. Although replication is necessary, these findings highlight the importance of repeated phenotypic assessments across development and modeling both distal and proximal environments and their interaction with genetic susceptibility at specific developmental stages. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Adsorption of haematoporphyrins on the planar bilayer membrane

Adsorption of haematoporphyrin derivatives with different hydrophobicities of peripheral groups on a planar bilayer lipid membrane (BLM) was studied in the dark and upon illumination by the visible light. Haematoporphyrin molecules were shown to adsorb on the BLM as anions. The adsorption changed the boundary potential at the membrane/water interface, in particular, it altered the potential in the diffuse part of the double layer outside the membrane and increased an additional unscreenable potential drop inside it. Illumination decreased the value of the negative potential drop due probably to the appearance of a positive charge in the haematoporphyrin macrocycle. The adsorption of haematoporphyrins affected the BLM conductivity induced by different ionophores, which can be explained by changes in membrane structure. Haematoporphyrin derivatives with higher hydrophobicities adsorbed deeper inside the membrane, caused greater changes in its structure and displayed a stronger photodynamic effect.     

The theta rhythm of the infant EEG and the development of the mechanisms of voluntary control of attention in the 2nd half of the first year of life

The neurophysiological basis of attention control was studied in infants at the second half-year of life, i.e. in the period when the capability for voluntary control over behavior fundamentally improves. EEG was recorded in 60 infants aed 8-11 months in three experimental conditions: 1) attention to an object in the visual field (externally controlled attention, or the baseline state), 2) anticipation of a person in the peek-a-boo game (internally controlled attention), 3) attention to the reappeared person in the peek-a-boo game (control condition). The spectral analysis of the EEG data revealed a sharp increase in the EEG theta (3.6-6.0 Hz) during internally controlled attention as compared to the baseline and control conditions. The theta1 (3.6-4.8 Hz) increase was maximal in the frontal derivations. The reactivity of the frontal theta1 during internally controlled attention discriminated infants with different abilities to maintain this type of attention. The reactivity of the theta2 (5.2-6.0 Hz) was maximal in the right temporal derivation (T6) and did not depend on stability of the anticipatory attention. The findings point to different functional significance of the theta1 and theta2 rhythms in infants. It is suggested that synchronization of the frontal theta1 rhythm in infants reflects the activity of the anterior attention system which realizes the executive attention control. The ability to maintain anticipatory attention increased with age, whereas the frontal theta1 synchronization decreased and totally disappeared at the age of 11 months. At the age of 8 months there was a positive correlation between the frontal theta1 synchronization and behavioral index of stability of the internally controlled attention. On the contrary, this correlation was negative at the age of 9 and 10 months. It is suggested that the age-dependent dynamics of the relationship between the frontal theta1 reactivity and attention reflects a leap in maturation of the anterior attention system resulting in its more economic and efficient functioning.