Binding of small mono- and oligomeric integrin ligands to membrane-embedded integrins monitored by surface plasmon-enhanced fluorescence spectroscopy

We recently developed a binding assay format by incorporating native transmembrane receptors into artificial phospholipid bilayers on biosensor devices for surface plasmon resonance spectroscopy. By extending the method to surface plasmon-enhanced fluorescence spectroscopy (SPFS), sensitive recording of the association of even very small ligands is enabled. Herewith, we monitored binding of synthetic mono- and oligomeric RGD-based peptides and peptidomimetics to integrins alphavbeta3 and alphavbeta5, after having confirmed correct orientation and functionality of membrane-embedded integrins. We evaluated integrin binding of RGD multimers linked together via aminohexanoic acid (Ahx) spacers and showed that the dimer revealed higher binding activity than the tetramer, followed by the RGD monomers. The peptidomimetic was also found to be highly active with a slightly higher selectivity toward alphavbeta3. The different compounds were also evaluated in in vitro cell adhesion tests for their capacity to interfere with alphavbeta3-mediated cell attachment to vitronectin. We hereby demonstrated that the different RGD monomers were similarly effective; the RGD dimer and tetramer showed comparable IC50 values, which were, however, significantly higher than those of the monomers. Best cell detachment from vitronectin was achieved by the peptidomimetic. The novel SPFS-binding assay platform proves to be a suitable, reliable, and sensitive method to monitor the binding capacity of small ligands to native transmembrane receptors, here demonstrated for integrins.     

Infrared absorption spectra of adsorbed dinitrogen on RuAl2O3K below 2000 cm−1

A new dinitrogen species is found by ir absorption at 1935 cm^?1 (Type B) when a dinitrogen species at 2020 cm^?1 (Type A) prepared from N₂ on RuAl₂O₃K is treated with H₂ above 170 °C or with NH₃ at 25 °C, or when H₂-treated catalyst is treated with N₂ at 250 °C. The Type B species is more reactive to H₂ or O₂ than the Type A species. Another ir band is found at around 1870 cm^?1 (Type C) when Type B species is evacuated at 200 °C. Both species, B and C, are likely located on the surface, while the Type A species is in an absorbed state. The Type C species is removed rapidly on introduction of H₂ or NH₃ at 25 °C, probably by displacement. The very low wavenumber, the high sensitivity to gases, and the high stability to evacuation disclose the unique character of the Type C species.     

Analysis of measured isotopic compositions of high-burnup PWR MOX and UO2 fuels in the MALIBU program

The measured isotopic compositions of fuel samples taken from high-burnup spent PWR MOX and UO₂ assemblies in the MALIBU program has been analyzed by lattice physics codes. The measured isotopes were U, Np, Pu, Am, and Cm isotopes and about 30 major fission product nuclides. The codes used in the present study were a continuous-energy Monte Carlo burnup calculation code (MVP-BURN) and a deterministic burnup calculation code (SRAC) based on the collision probability method. A two-dimensional multi-assembly geometrical model (2 × 2 model) was mainly adopted in the analysis in order to include the fuel assemblies adjoining the relevant fuel assembly, from which the samples were taken. For the MOX sample, the 2 × 2 model significantly reduces the deviations of the calculated results from the measurements compared with a single assembly model. The calculation results of MVP-BURN in the 2 × 2 model reproduce the measurements of U, Np, and Pu isotopes within 5% for the MOX sample of 67 GWd/t. The deviations of their calculated results of U, Np, and Pu isotopes from the measurements are less than 7% for the UO₂ sample of 72 GWd/t.     

Infection of the Sunagoke moss panels with fungal pathogens hampers sustainable greening in urban environments

Drought and heat tolerance of the Sunagoke moss (Racomitrium japonicum) and the low thermal conductivity of the dry moss tissue offer novel greening and insulation possibilities of roofs and walls to mitigate the heat island phenomenon in urban environments. However, damage may appear in the moss panels under humid conditions in Japan. In this study we characterized fungi associated with the damaged areas of the Sunagoke moss panels. Fungi were identified by morphology and internal transcribed spacer (ITS) sequence analysis and tested for pathogenicity on R. japonicum (Grimmiaceae) and an unrelated moss species (Physcomitrella patens; Funariaceae) under controlled conditions. Alternaria alternata, Fusarium avenaceum and Fusarium oxysporum caused severe necrosis and death, whereas Cladosporium oxysporum and Epicoccum nigrum caused milder discoloration or chlorosis in both moss species. The fungi pathogenic on moss were closely related to fungal pathogens described from cultivated vascular plants. Ammonium increased severity of fungal diseases in moss. This study demonstrated that fungi can cause economically significant diseases in cultivated moss and hamper commercial use of the moss panels unless appropriate control methods are developed. Use of a single moss clone to cover large surfaces and the air pollutants such as ammonium may increase the risk for fungal disease problems.     

Deactivation kinetics of Escherichia coli cells correlated with intracellular superoxide dismutase activity in photoreaction with titanium dioxide particles

In the photoreaction of Escherichia coli IM303 (superoxide dismutase (SOD)‐deficient mutant) and MM294 (wild‐type strain) with TiO₂ particles, the viability of strain IM303 decreased linearly with photoreaction time, while the time profile of the viability of strain MM294 exhibited a curved form. Using strain MM294 with varied initial SOD activities, the TiO₂ photoreaction tests were conducted at incident light intensities of I₀ = 4,8 and 14 W m^?2, and the time profiles of bacterial viabilities were analyzed on the basis of the series‐event model. The value of n (corresponding to the step number in the series reaction kinetics described by the model) increased with an increase in initial SOD activity (A_SOD,0), giving a mean value of A_SOD,0/n = 7.1 × 10^?9 U cell^?1 under the conditions examined. SOD activities in the cells of strain MM294 with A_SOD,0 = 1.9 × 10^?8 and 4.0 × 10^?8 U cell^?1 decreased with the progress of photoreaction conducted at I₀ = 14 W m^?2. The transition of intracellular SOD activities expressed was in agreement with the observed data by considering the changes in bacterial cell populations with varied SOD activities based on the proposed model. © 2002 Society of Chemical Industry     

Flexible Modulation of Electronic Band Structures of Wide Band Gap GaN Semiconductors Using Bioinspired,Nonbiological Helical Peptides

Modulation of the electronic band profiles of wide band gap GaN semiconductors is achieved by the macromolecular dipole potentials exerted from ordered monolayers of synthetic, nonbiological aldehyde terminated helical peptides deposited on wet chemically oxidized GaN surfaces functionalized with aminosilanes. The selective coupling of either N‐ or C‐terminal to the amino‐terminated surface enables one to control the direction of the dipole moment, while the number of amino acids determines its magnitude. After confirming the formation of highly ordered peptide monolayers, the impact of macromolecular dipole potentials is quantified by electrochemical impedance spectroscopy. Moreover, the chronoamperometry measurements of ferrocene‐terminated peptides suggest that the transfer of electrons injected from ferrocene follows inelastic hopping, while the current responses of peptides with no ferrocene moieties are purely capacitive. Finally, the same functionalization steps are transferred to GaN/AlGaN/GaN high electron mobility transistor structures. Stable and quantitative modulation of the current–voltage characteristics of the 2D electron gas by the deposition of bioinspired peptides is a promising strategy for the macromolecular dipole engineering of GaN semiconductors.     

Distinct Age-Specific miRegulome Profiling of Isolated Small and Large Intestinal Epithelial Cells in Mice

The intestinal epithelium serves as a dynamic barrier to protect the host tissue from exposure to a myriad of inflammatory stimuli in the luminal environment. Intestinal epithelial cells (IECs) encompass differentiated and specialized cell types that are equipped with regulatory genes, which allow for sensing of the luminal environment. Potential inflammatory cues can instruct IECs to undergo a diverse set of phenotypic alterations. Aging is a primary risk factor for a variety of diseases; it is now well-documented that aging itself reduces the barrier function and turnover of the intestinal epithelium, resulting in pathogen translocation and immune priming with increased systemic inflammation. In this study, we aimed to provide an effective epigenetic and regulatory outlook that examines age-associated alterations in the intestines through the profiling of microRNAs (miRNAs) on isolated mouse IECs. Our microarray analysis revealed that with aging, there is dysregulation of distinct clusters of miRNAs that was present to a greater degree in small IECs (22 miRNAs) compared to large IECs (three miRNAs). Further, miRNA–mRNA interaction network and pathway analyses indicated that aging differentially regulates key pathways between small IECs (e.g., toll-like receptor-related cascades) and large IECs (e.g., cell cycle, Notch signaling and small ubiquitin-related modifier pathway). Taken together, current findings suggest novel gene regulation pathways by epithelial miRNAs in aging within the gastrointestinal tissues.     

A novel analytical approach for a vector‐controlled,adjustable‐speed synchronous machine

A novel approach for operation analysis of a vector control synchronous machine has been described. To draw the vector diagram under adjustable speed operation, the concept of normalized voltage has been introduced. It is to divide the voltage value by angular frequency of the machine, then the voltage vectors, which contain angular frequency immanently, will not change their length under adjustable speed operation, and the vector diagram will keep its size unchanged for the whole speed range. Also, reactance drop locus and its accompanying yardstick circle for determining current phase angle, in corresponding to the variation of the given armature current vector, were deduced. Then, the operation of the machine for the whole adjustable speed range can be represented in single diagram. As the accompanying matters, the methods for calculating the operating characteristics of maximum torque control and 100% power factor control were shown. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(2): 48–56, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10058