Optical Property Analyses of Plant Cells for Adaptive Optics Microscopy

In astronomy, adaptive optics (AO) can be used to cancel aberrations caused by atmospheric turbulence and to perform diffraction-limited observation of astronomical objects from the ground. AO can also be applied to microscopy, to cancel aberrations caused by cellular structures and to perform high-resolution live imaging. As a step toward the application of AO to microscopy, here we analyzed the optical properties of plant cells. We used leaves of the moss Physcomitrella patens, which have a single layer of cells and are thus suitable for optical analysis. Observation of the cells with bright field and phase contrast microscopy, and image degradation analysis using fluorescent beads demonstrated that chloroplasts provide the main source of optical degradations. Unexpectedly, the cell wall, which was thought to be a major obstacle, has only a minor effect. Such information provides the basis for the application of AO to microscopy for the observation of plant cells.     

Double-passed arrayed waveguide grating for 500-GHz pulse burst generation

500-GHz repetition rate pulse bursts on multiple wavelength shifted channels are generated via femtosecond readout of an arrayed waveguide grating (AWG). These bursts are combined onto a single channel by double-passing the AWG, resulting in a substantially increased number of output pulses.     

Phosphorylation of alphaB-crystallin in mitotic cells and identification of enzymatic activities responsible for phosphorylation

The immunofluorescence localization of alphaB-crystallin in U373 MG human glioma cells with an antibody specific for alphaB-crystallin that had been phosphorylated at Ser-45 revealed an intense staining of cells in the mitotic phase of the cell cycle. Phosphorylated forms of alphaB-crystallin in mitotic cells were detected in all cell lines examined and in tissue sections of mouse embryos. Increases in the levels of alphaB-crystallin that had been phosphorylated at Ser-45 and Ser-19, but not at Ser-59, were detected biochemically by isoelectric focusing or SDS-polyacrylamide gel electrophoresis and a subsequent Western blot analysis of extracts of cells collected at the mitotic phase. When we estimated the phosphorylation activity specific for alphaB-crystallin in extracts of mitotic U373 MG cells, using the amino-terminal 72-amino acid peptide derived from unphosphorylated alphaB2-crystallin as the substrate, we found that the activities responsible for the phosphorylation of Ser-45 and Ser-19 were markedly enhanced but that the activity responsible for the phosphorylation of Ser-59 was suppressed. The protein kinases responsible for the phosphorylation of Ser-45 and Ser-59 in the amino-terminal 72-amino acid peptide were partially purified from extracts of cells that had been stimulated by exposure to H2O2 in the presence of calyculin A. The activities responsible for the phosphorylation of Ser-45 and Ser-59 were eluted separately from a column of Superdex 200 at fractions corresponding to about 40 and 60 kDa, respectively, while the kinase for Ser-19 was unstable. p44/42 mitogen-activated protein (MAP) kinase and MAP kinase-activated protein (MAPKAP) kinase-2 were concentrated in the Ser-45 kinase fraction and Ser-59 kinase fraction, respectively. Recombinant human p44 MAP kinase and MAPKAP kinase-2 purified from rabbit muscle selectively phosphorylated Ser-45 and -59, respectively. The Ser-45 kinase fraction and Ser-59 kinase fraction phosphorylated myelin basic protein and hsp27, respectively. These results suggest that the phosphorylations of Ser-45 and Ser-59 in alphaB-crystallin are catalyzed by p44/42 MAP kinase and MAPKAP kinase-2, respectively, in cells and that the phosphorylation of Ser-45 by p44/42 MAP kinase is enhanced while the phosphorylation of Ser-59 by MAPKAP kinase-2 is suppressed during cell division.     

8-channel×2.5 Gbit/s hybrid integrated multiwavelengthphotoreceiver module with arrayed-waveguide grating demultiplexer

A compact 8-channel hybrid integrated multiwavelength photoreceiver module has been fabricated. The module, which consists of an arrayed-waveguide grating demultiplexer with a 100 GHz spacing, a photodiode array using a planar lightwave circuit platform, and preamplifier integrated circuits, successfully operated at 2.5 Gbit/s with good receiver sensitivity better than -17.5 dBm at a bit error rate of 10^-9 for all channels     

Partial properties of four glycosidases in normal human lens and variations in their enzyme activities during aging and with the advance of lens coloration

This paper reports the active glycosidases in normal human lenses and their partial properties. In addition, variations in their enzyme activities during aging and with the advance of lens coloration were also examined. Five glycosidases, alpha-glucosidase, beta-D-glucuronidase, N-acetyl-beta-D-glucosaminidase, beta-D-cellobiosidase, and alpha-L-fucosidase, were detected as active glycosidases in the normal human lens. However, the activity of beta-D-cellobiosidase was considerably low as compared to the other four glycosidases. Thus, this enzyme was omitted from this study. The four glycosidases, alpha-D-glucosidase, beta-D-glucuronidase, N-acetyl-beta-D-glucosaminidase, and alpha-L-fucosidase, showed that their enzyme activities fell abruptly between the ages of 40 and 50. Furthermore, the Km values of their enzymes exhibited some variability during aging. Namely, the Km values of their enzymes indicated the lowest value between the 40 age group and 50 age group, suggesting that the substrate affinity became the strongest at these age groups. Then, variations in enzyme activity with the advance of lens coloration were examined. In each cases, the specific activity of detectable glycosidases in color lenses, white to brown, decreased. In particular, the specific activity of enzymes in the brown lens was very low, indicating that glycosidases in the brown lens may scarcely display their enzyme activities.     

Feature extraction of AR as a performance index for load frequency controls of interconnected power systems

Recently, the evaluation of control performances of interconnected power systems has become an important issue with respect to individual load frequency controls. Several performance measures are in practical use such as Area Control Error (ACE), Mutual Aid Criterion (MAC), and Control Performance Standard (CPS). Area Requirement (AR) is an alternative expression for ACE, where AR=?ACE. However, the characteristics of these indices have not been sufficiently studied as far as the authors know. In particular, this is the case for their dynamic behavior against random load disturbances. This paper investigates the performance index, AR, through analysis of two‐area systems. Major dynamic elements of interconnected systems affecting the frequency are taken into account to investigate responses of the system against load disturbances. The analysis shows that, when new systems are interconnected, the smaller system tends to require more effort of control against load disturbances to keep the same value of the performance indices. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(1): 20–28, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20233     

Some unusual responses of astrocytes to ghost tangles in a long duration case of juvenile Alzheimer''s disease: an electron microscopic study

Clavulanic acid (CA) was produced by Streptomyces clavuligerus in medium containing glycerol and soy meal or soy meal extract. With regard to growth and CA productivity, the microorganism showed significant differences if solid soy meal as such or its extract were applied as the major nitrogen source. If the extract is used, growth and CA production take place simultaneously and in the stationary phase the CA concentration is stagnant or reduces. If soy meal is used, growth is threefold faster and CA is only generated in the stationary phase. In the case of using the soy meal extract, the decrease of the CA concentration is mainly due to decomposition or re-metabolisation of CA in the presence of the microorganism. This conclusion is supported by in vivo and in vitro data on CA decomposition.     

Thickness dependence of structural and ferroelectric properties of sol-gel Pb(Zr0.56Ti0.44)0.90(Mg1/3Nb2/3)0.10O3 films

Sol-gel Pb(Zr_0.56Ti_0.44)_0.90(Mg_1/3Nb_2/3)_0.10O₃ (PZT-PMN) films were prepared onto the Ti/Pt/Ti bottom electrode by multilayer spin coating. The film thickness ranged from 0.22 to 0.88 μm. The Pt top electrodes were deposited on the PZT-PMN films by DC sputtering. The structural and ferroelectric properties of PZT-PMN films were investigated as a function of film thickness by X-ray diffraction (XRD), scanning electron microscopy (SEM), cross-sectional transmission electron microscopy (XTEM), and by measuring the relative permittivity. The film retains the tetragonal perovskite structure with the [111] and [100] preferred orientations perpendicular to the film surface independent of film thickness. The [100] texture increases with increasing film thickness although the [111] texture is always predominant. The film consists of columnar grains. The average grain size is nearly independent of film thickness. The surface layer containing fine grains about 30 nm in diameter is induced on the top of the film. As the film thickness exceeds 0.44 μm, the number of the fine grains decreases remarkably. The crystalline interface layer about 10 nm thick is formed between the film and the bottom electrode. This interface layer is composed of Pt, Pb, Zr, Ti and O, while it is rich in Ti and deficient in Pb and O as compared with the inside of the film. The measured relative permittivity of the film increases with increasing film thickness, following the low permittivity interface model. On the basis of this model, the relative permittivity is estimated to be 3200 for the intrinsic PZT-PMN film, 750 for the surface layer and 50 for the interface layer.     

Brief note—A criterion for unstable elastic-plastic brittle fracture based on more realistic model under plane stress

A criterion for unstable elastic-plastic brittle fracture under plane stress was previously proposed based on energy balance considerations, in which the plastic work term was used based on Dugdale model of plastic zone pattern. The realistic pattern, however, of the plastic zone is far from a Dugdale model. Therefore, in this article, a more realistic pattern is used.As a result, a more realistic criterion for unstable elastic-plastic brittle fracture has been obtained. In this new criterion, +p appears in place of the material surface energy term in the previous criterion, where p is the plastic work term corresponding to the excess plastic zone pattern extending in the direction perpendicular to the crack propagation direction beyond over the boundary of Dugdale model.

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Zusammenfassung Man hatte eine Kennzeichnung für den unstabilen elasto-plastischen Sprödbruch unter planer Beanspruchung vorgeschlagen, welche auf Energiebilanzüberlegungen beruhte, wobei das die plastische Arbeit beschreibende Glied auf dem Dugdale-Modell für plastische Verformungszonen begründet war.Der wirkliche Vorgang im plastischen Bereich ist jedoch weft vom Dugdale-Modell entferm. Deshalb wird im vorliegenden Bericht von realistischeren Vorstellungen ausgegangen.Hierbei ergibt sich eine wirklichkeitsgetreuere Kennzeichnung des unstabilen elasto-plastischen Sprödbruchs. In diesem neuen Ausdruck erscheint die Summe +p an Stelle der Materialoberflächenenergie y in dem früheren Kriterium, wobei p die plastische Verformungsarbeit für die plastischen Bereiche darstellt, welche senkrecht zur RiBfortpflanzungsrichtung, jenseits der vom Dugdale-Modell vorgesehenen Grenze liegen.

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Résumé On a précédemment proposé un critère, basé sur des considérations d'équilibre énergétique, pour la rupture fragile en conditions élasto-plastique et sous état plan de tension. Dans ce critère, on faisait appel au travail plastique, sur la base du modèle du Dugdale relatif aux configurations des zones de déformation plastique.La configuration réelle de ces zones est, toutefois, assez différente de celle du modèle de Dugdale. On a donc consideré, dans ce mémoire, une configuration plus réaliste.On a ainsi obtenu un critere, plus réaliste, de la rupture fragile élasto-plastique. Dans celui-ci,l'ènergie de surface du précédent critère a été remplacé par un terme +p, où p représente le travail de déformation plastique correspondant aux zones plastiques qui s'étendent, perpendiculairement à l'axe de propagation de la fissure, au-delà de la limite prévue par Dugdale.

     

Association analysis of the SHC1 gene locus with longevity in the Japanese population

The SHC1 gene encodes a signaling and transforming protein that has been implicated in the aging process in worms and mammals. In this study we examined 230 Japanese centenarians and 180 healthy younger controls and looked at the SHC1 locus as a candidate region that may be associated with longevity. We identified 12 single nucleotide polymorphisms (SNPs) within a 10-kb region encompassing the entire SHC1 gene from the DNA of 30 centenarians and 24 healthy younger controls. Five SNPs, including three nonsynonymous sites, lay within coding elements, six were located within introns, and one was in the 3' untranslated region. All of these SNPs were relatively rare, with a minor allele frequency of less than 5% in our subjects. A pairwise linkage disequilibrium analysis using the r2 statistic showed that two of the SNP pairs are in tight linkage disequilibrium at this locus. We investigated the possible association of SHC1 with longevity using association analyses with allelotypes and haplotypes but found that the SNPs identified in SHC1 had no impact on longevity for Japanese centenarians.