Microfabrication of U-Shaped Grooves on the Surface of BaO–TiO2–GeO2 Glass by YAG Laser Irradiation and Selective Chemical Etching

A combination technique of Nd:YAG laser (wavelength: 1064 nm) irradiations and chemical etchings was applied to fabricate microsize U-shaped grooves on the surface of CuO-doped BaO–TiO₂–GeO₂ glass, and chemical etching behaviors were examined by using a confocal scanning laser microscope. Continuous-wave Nd:YAG lasers with a power of 0.7–0.8 W were irradiated onto the glass surface and scanned at a speed of 10 μm/s, inducing structural modified lines with refractive index changes. The chemical etching rates for the refractive index changed lines in a nitric acid solution (1 N HNO₃) were larger than those for the base glass (nonirradiated part). The etching profile was changed gradually from W-shaped to U-shaped grooves with increasing etching time. The sharp bending lines with an angle of 150° and the cross-linked lines were also smoothly etched. The U-shaped grooves with a surface covered by nonlinear optical Ba₂TiGe₂O₈ crystals were formed by the crystallization of etched samples. This study proposes that the patterning of microchannels with optical functional surfaces is possible on the glass surface using the present technique.     

Transport-Coefficient Dependence of Current-Induced Cooling Effect in a Two-Dimensional Electron Gas

The dependence of the current-induced cooling effect on the electron mobility??? _e is explored for a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field. We calculate the distributions of the electrochemical potentials and the temperatures under a magnetic field, fully taking account of thermoelectric and thermomagnetic phenomena. Whereas the electrochemical potential and the electric current remain qualitatively unchanged, the temperature distribution exhibits drastic mobility dependence. The lower-mobility system has cold and hot areas at opposite corners, which results from the heat current brought about by the Ettingshausen effect in the vicinity of the adiabatic boundaries. The cooling effect is intensified by an increase in??? _e. Intriguingly, the cold and hot areas change places with each other as the mobility??? _e is further increased. This is because the heating current on the adiabatic edges due to the Righi?CLeduc effect exceeds that due to the Ettingshausen effect in the opposite direction.     

Engineering of novel tamavidin 2 muteins with lowered isoelectric points and lowered non-specific binding properties

The avidin-biotin interaction is widely employed as a universal tool in numerous biotechnological applications. In avidin-biotin technology, non-specific binding to biological macromolecules is a hindrance. The major origin of this non-specific binding is the electrical charge of the surface of biotin-binding proteins. Tamavidin 2, a fungal avidin-like protein that binds biotin with an extremely high affinity, can be produced as a soluble recombinant protein in Escherichia coli. The isoelectric point of tamavidin 2 is 7.4-7.5, lower than avidin (10.0), and slightly higher than that of streptavidin (6.0-7.5). Here, we genetically engineered charge mutants of tamavidin 2 to reduce non-specific binding. By substituting an acidic residue (glutamic acid) for basic residues (arginine and lysine), we constructed three mutant proteins (muteins) and confirmed their high-level production in soluble form in E. coli, as well as that of tamavidin 2.?We then tested these proteins for non-specific binding to salmon sperm DNA, glycoproteins (integrin and fibronectin), and IgG from human sera. The muteins showed lower non-specific binding than tamavidin 2 to these macromolecules. In particular, one mutein, tamavidin-R104EK141E, which had the lowest isoelectric point (5.8-6.2) among avidin, streptavidin and tamavidin 2, displayed the lowest non-specific binding. The affinity of this mutein to biotin was high, comparable with that of tamavidin 2. These findings indicate that tamavidin-R104EK141E has the potential to serve as a robust tool in the numerous applications of biotin-binding proteins.     

In situ localization of beta-glucans in the cell wall of Schizosaccharomyces pombe

The chemical composition of the cell wall of Sz. pombe is known as beta-1,3-glucan, beta-1,6-glucan, alpha-1,3-glucan and alpha-galactomannan; however, the three-dimensional interactions of those macromolecules have not yet been clarified. Transmission electron microscopy reveals a three-layered structure: the outer layer is electron-dense, the adjacent layer is less dense, and the third layer bordering the cell membrane is dense. In intact cells of Sz. pombe, the high-resolution scanning electron microscope reveals a surface completely filled with alpha-galactomannan particles. To better understand the organization of the cell wall and to complement our previous studies, we set out to locate the three different types of beta-glucan by immuno-electron microscopy. Our results suggest that the less dense layer of the cell wall contains mainly beta-1,6-branched beta-1,3-glucan. Occasionally a line of gold particles can be seen, labelling fine filaments radiating from the cell membrane to the alpha-galactomannan layer, suggesting that some of the radial filaments contain beta-1,6-branched beta-1,3-glucan. beta-1,6-glucan is preferentially located underneath the alpha-galactomannan layer. Linear beta-1,3-glucan is exclusively located in the primary septum of dividing cells. beta-1,6-glucan only labels the secondary septum and does not co-localize with linear beta-1,3-glucan, while beta-1,6-branched beta-1,3-glucan is present in both septa. Linear beta-1,3-glucan is present from early stages of septum formation and persists until the septum is completely formed; then just before cell division the label disappears. From these results we suggest that linear beta-1,3-glucan is involved in septum formation and perhaps the separation of the two daughter cells. In addition, we frequently found beta-1,6-glucan label on the Golgi apparatus, on small vesicles and underneath the cell membrane. These results give fresh evidence for the hypothesis that beta-1,6-glucan is synthesized in the endoplasmic reticulum-Golgi system and exported to the cell membrane.     

Pre-treatment of sperm reduces success of ICSI in the pig

In pigs, although ICSI is a feasible fertilization technique, its efficiency is low. In general, injected pig sperm are insufficient to induce oocyte activation and embryonic development. Pretreatments for disrupting sperm membranes have been applied to improve the fertility of ICSI oocytes; however, we hypothesize that such pretreatment(s) may reduce the ability of the sperm to induce oocyte activation. We first evaluated the effects of sperm pretreatments (sonication (SO) to isolate the sperm heads from the tails, Triton X-100 (TX), and three cycles of repeated freezing/thawing (3×-FT) for disrupting sperm membranes) on the rate of pronucleus (PN) formation after ICSI. We found that oocytes injected with control (whole) sperm had higher rates of PN formation than those obtained after subjecting the sperm to SO, TX, and 3×-FT. The amounts of phospholipase Cζ (PLCζ), which is thought to be the oocyte-activating factor in mammalian sperm, in sperm treated by each method was significantly lower than that in whole untreated sperm. Furthermore, using immunofluorescence, it was found that in pig sperm, PLCζ was localized to both the post-acrosomal region and the tail area. Thus we demonstrated for the first time that sperm pretreatment leads to a reduction of oocyte-activating capacity. Our data also show that in addition to its expected localization to the sperm head, PLCζ is also localized in the tail of pig sperm, thus raising the possibility that injection of whole sperm may be required to attain successful activation in pigs.     

Developmental trajectories in toddlers' self-restraint predict individual differences in executive functions 14 years later: A behavioral genetic analysis.

We examined whether self-restraint in early childhood predicted individual differences in 3 executive functions (EFs; inhibiting prepotent responses, updating working memory, and shifting task sets) in late adolescence in a sample of approximately 950 twins. At ages 14, 20, 24, and 36 months, the children were shown an attractive toy and told not to touch it for 30 s. Latency to touch the toy increased with age, and latent class growth modeling distinguished 2 groups of children that differed in their latencies to touch the toy at all 4 time points. Using confirmatory factor analysis, we decomposed the 3 EFs (measured with latent variables at age 17 years) into a Common EF factor (isomorphic to response inhibition ability) and 2 factors specific to updating and shifting. Less-restrained children had significantly lower scores on the Common EF factor, equivalent scores on the Updating-Specific factor, and higher scores on the Shifting-Specific factor than did the more-restrained children. The less-restrained group also had lower IQ scores, but this effect was entirely mediated by the EF components. Twin models indicated that the associations were primarily genetic in origin for the Common EF variable but split between genetics and nonshared environment for the Shifting-Specific variable. These results suggest a biological relation between individual differences in self-restraint and EFs, one that begins early in life and persists into late adolescence. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Orientation-preserving transfer and directional light scattering from individual light-bending nanoparticles

A nanocup, or semishell, is an asymmetric plasmonic "Janus" nanoparticle with electric and magnetic plasmon modes; the latter scatters light in a direction controlled by nanoparticle orientation, making it the nanoscale analog of a parabolic antenna. Here we report a method for transferring nanocups from their growth substrate to oxide-terminated substrates that precisely preserves their three-dimensional orientation, enabling their use as nanophotonic components. This enables us to selectively excite and probe the electric and magnetic plasmon modes of individual nanocups, showing how the scattered light depends on the direction of incoming light and the orientation of this nanoparticle antenna.     

Suicidality as a function of impulsivity, callous–unemotional traits, and depressive symptoms in youth.

Suicidality represents one of the most important areas of risk for adolescents, with both internalizing (e.g., depression, anxiety) and externalizing–antisocial (e.g., substance use, conduct) disorders conferring risk for suicidal ideation and attempts (e.g., Bridge, Goldstein, & Brent, 2006). However, no study has attended to gender differences in relationships between suicidality and different facets of psychopathic tendencies in youth. Further, very little research has focused on disentangling the multiple manifestations of suicide risk in the same study, including behaviors (suicide attempts with intent to die, self-injurious behavior) and general suicide risk marked by suicidal ideation and plans. To better understand these relationships, we recruited 184 adolescents from the community and in treatment. As predicted, psychopathic traits and depressive symptoms in youth showed differential associations with components of suicidality. Specifically, impulsive traits uniquely contributed to suicide attempts and self-injurious behaviors, above the influence of depression. Indeed, once psychopathic tendencies were entered in the model, depressive symptoms only explained general suicide risk marked by ideation or plans but not behaviors. Further, callous–unemotional traits conferred protection from suicide attempts selectively in girls. These findings have important implications for developing integrative models that incorporate differential relationships between (a) depressed mood and (b) personality risk factors (i.e., impulsivity and callous–unemotional traits) for suicidality in youth. (PsycINFO Database Record (c) 2011 APA, all rights reserved)