CO2 hydrogenation over micro‐ and mesoporous oxides supported Ru catalysts

We prepared relatively uniform supported Ru catalysts by ion‐exchange and CVD methods, using an NaY zeolite and a mesoporous FSM‐16 as substrates, and carried out CO₂ hydrogenation. They showed high activity for CO₂ hydrogenation. A Ru‐ion‐exchanged catalyst showed high activity for methanol production. Co addition promoted methanol formation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hydrogen adsorption and hydrogen evolution reaction on a polycrystalline Pt electrode studied by surface-enhanced infrared absorption spectroscopy

Hydrogen evolution reaction (HER) on a polycrystalline Pt electrode has been investigated in Ar-purged acids by surface-enhanced infrared absorption spectroscopy and electrochemical kinetic analysis (Tafel plot). A vibrational mode characteristic to H atom adsorbed at atop sites (terminal H) was observed at 2080-2095 cm⁻¹. This band appears at 0.1 V (RHE) and grows at more negative potentials in parallel to the increase in hydrogen evolution current. Good signal-to-noise ratio of the spectra enabled us to establish the quantitative relation between the band intensity (equivalently, coverage) of terminal H and the kinetics of HER, from which we conclude that terminal H atom is the reaction intermediate in HER and the recombination of two terminal H atoms is the rate-determining step. The quantitative analysis of the infrared data also revealed that the adsorption of terminal H follows the Frumkin isotherm with repulsive interaction.     

Thermal modulation of intracellular drug distribution using thermoresponsive polymeric micelles

Intracellular distribution of free doxorubicin (DOX) or DOX-loaded in polymeric micelles with thermoresponsive outer shells of poly(N-isopropylacrylamide) or its copolymers in cultured human breast cancer cells (MCF-7) were investigated by fluorescence and confocal laser scanning microscopy. Free DOX accumulated rapidly and selectively in cell nuclei, independent of temperature changes. In contrast to free drugs, the intracellular distribution of DOX-loaded in the thermoresponsive polymeric micelles was significantly affected by temperature changes across lower critical solution temperature (LCST) of the micelles. Above the micelle LCST, DOX delivered by the micelles was localized uniformly inside of MCF-7 cells. By contrast, the amount of DOX delivered to MCF-7 cells drastically decreased below the micelle LCST due to minimal interaction of the micelles with cell membrane surfaces. These results clearly showed that the mechanism of the intracellular drug localization was different between free drugs and DOX-loaded in the micelles. The thermoresponsive micelles aggressively interacted with the cells and carried DOX into the cells via triggered phase transition of the outer shells. In addition, much lower accumulation of free DOX was observed in the resistant cells compared to its parent sensitive MCF-7 due to the resistant mechanism. Of interest, DOX accumulation in the resistant cells was almost in the same level as with MCF-7 (sensitive) cells for the micelle system above the LCST.     

Structural Study on PbO–SiO2 Glasses by X-Ray and Neutron Diffraction and 29Si MAS NMR Measurements

Structure of x PbO–(100− x )SiO₂ ( x =25–89) glasses has been investigated by means of the X-ray and neutron diffraction and ²⁹Si MAS NMR measurements. In the radial distribution functions of all the glasses, the Pb–O correlation was observed at 0.23 nm, indicating that the PbO₃ trigonal pyramids units do exist in the whole glass forming composition range. Furthermore the existence of the first Pb–Pb correlation at ∼0.385 nm in the whole composition range suggests that the basic structural unit is considered to be a Pb₂O₄ unit, which consists of the edge-shared PbO₃ trigonal pyramids. These results strongly imply that the Pb₂O₄ units participate in the glass network constructed by SiO₄ tetrahedra even at low PbO content. Differing from other lead-containing glass systems, these structural characteristics of Pb ions in the PbO–SiO₂ glass system are responsible for the extremely wide glass-forming region.     

Enzymatic hydrolysis of lysine diisocyanate based polyurethanes and segmented polyurethane ureas by various proteases

This work studies the enzymatic degradation of polyurethanes (PUs) and segmented polyurethane ureas (SPUUs) derived from lysine diisocyanate (LDI) by various proteases. Thiol proteases, such as papain, bromelain, and ficin, showed high activity on PUs. Protease K and chymotrypsin also hydrolyzed the PUs. For almost all SPUUs, papain showed high activity. For example, LDI/poly(caprolactone) diol (M_w = 1250)/ethylene diamine (2/1/1) was hydrolyzed to 43% under the same conditions. The water-soluble degradation products of a polyurethane, LDI/BD (1/1), and two model compounds treated with papain were studied with NMR and GPC analysis. From the results, it was evident that the pendant methyl ester group in LDI was rapidly hydrolyzed, followed by slow hydrolysis of urethane bonds in the backbone chain.     

Validation of Platelet Counting Accuracy With the Celltac F Automated Hematology Analyzer

Rapid and accurate analysis of platelet count plays an important role in evaluating hemorrhagic status. Therefore, we evaluated platelet counting performance of a hematology analyzer, Celltac F (MEK-8222, Nihon Kohden Corporation, Tokyo, Japan), that features easy use with low reagent consumption and high throughput while occupying minimal space in the clinical laboratory. All blood samples were anticoagulated with dipotassium ethylenediaminetetraacetic acid (EDTA-2K). The samples were stored at room temperature (18^{^}C–22^{^}C) and tested within 4 hours of phlebotomy. We evaluated the counting ability of the Celltac F hematology analyzer by comparing it with the platelet counts obtained by the flow cytometry method that ISLH and ICSH recommended, and also the manual visual method by Unopette (Becton Dickinson Vacutainer Systems). The ICSH/ISLH reference method is based on the fact that platelets can be stained with monoclonal antibodies to CD41 and/or CD61. The dilution ratio was optimized after the precision, coincidence events, and debris counts were confirmed by the reference method. Good correlation of platelet count between the Celltac F and the ICSH/ISLH reference method (r = 0.99, and the manual visual method (r= 0.93) were obtained. The regressions were y = 0.90 x+9.0 and y=1.11x+8.4, respectively. We conclude that the Celltac F hematology analyzer for platelet counting was well suited to the ICSH/ISLH reference method for rapidness and reliability.     

Allelopathic Effects of Volatile Monoterpenoids Produced by <Emphasis Type="Italic">Salvia leucophylla</Emphasis>: Inhibition of Cell Proliferation and DNA Synthesis in the Root Apical Meristem of <Emphasis Type="Italic">Brassica campestris</Emphasis> Seedlings

Salvia leucophylla, a shrub observed in coastal south California, produces several volatile monoterpenoids (camphor, 1,8-cineole, -pinene, -pinene, and camphene) that potentially act as allelochemicals. The effects of these were examined using Brassica campestris as the test plant. Camphor, 1,8-cineole, and -pinene inhibited germination of B. campestris seeds at high concentrations, whereas -pinene and camphene did not. Root growth was inhibited by all five monoterpenoids in a dose-dependent manner, but hypocotyl growth was largely unaffected. The monoterpenoids did not alter the sizes of matured cells in either hypocotyls or roots, indicating that cell expansion is relatively insensitive to these compounds. They did not decrease the mitotic index in the shoot apical region, but specifically lowered mitotic index in the root apical meristem. Moreover, morphological and biochemical analyses on the incorporation of 5-bromo-2-deoxyuridine into DNA demonstrated that the monoterpenoids inhibit both cell-nuclear and organelle DNA synthesis in the root apical meristem. These results suggest that the monoterpenoids produced by S. leucophylla could interfere with the growth of other plants in its vicinity through inhibition of cell proliferation in the root apical meristem.     

Different support effect of M/ZrO2 and M/CeO2 (M = Pd and Pt) catalysts on CO adsorption: A periodic density functional study

CO adsorption over Pd₄ and Pt₄ cluster supported by c-ZrO₂(1 1 1) and CeO₂(1 1 1) catalyst systems was investigated using periodic density functional method in order to clarify the support effect on CO activation. We found that the support increases the CO activation for bridge and three-fold sites but decreases for the atop site. Moreover, it was found that the support changes the site preference for the CO adsorption. Bridge site on both the Pt₄/c-ZrO₂ and Pt₄/CeO₂ show larger CO adsorption energies than those on the other sites while the atop site is energetically preferable on isolated Pt₄ cluster. c-ZrO₂ supported Pd shows the largest CO activation with large charge transfer from the catalyst to the CO molecule. This reveals that ZrO₂ supported Pd can be a good catalyst for CO activation because of its higher probability to the three-fold site CO adsorption. We also found that positively charged M₄ clusters on the support keep their strong electron-donating properties and have enough charge density to contribute to the activation of an adsorbed CO molecule by a charge transfer.     

Motion optimization using state-dispersion-based phase space partitions

This paper addresses a phase space partitioning problem in motion planning systems. A class of kinematic and dynamic motion planning systems, including rapid semioptimal motion-planning (RASMO), uses partitions for phase spaces in cumulative optimization criteria. In these systems, a partition results in a uniquely planned motion with a quality that is determined by a selected optimization criterion. In this paper, state-dispersion-based phase space partitioning (SDPP) that generates adaptive partitions is proposed. These partitions allow the motion planning systems to plan better motions. Uniform partitions and adaptively fixed partitions of SDPP are compared under several conditions using RASMO and a double inverted pendulum model while setting the optimality criterion of RASMO to time. The results reveal that RASMO with SDPP plans smaller time motions than those obtained with RASMO using uniform partitions.     

Preserving worker privacy in crowdsourcing

This paper proposes a crowdsourcing quality control method with worker-privacy preservation. Crowdsourcing allows us to outsource tasks to a number of workers. The results of tasks obtained in crowdsourcing are often low-quality due to the difference in the degree of skill. Therefore, we need quality control methods to estimate reliable results from low-quality results. In this paper, we point out privacy problems of workers in crowdsourcing. Personal information of workers can be inferred from the results provided by each worker. To formulate and to address the privacy problems, we define a worker-private quality control problem, a variation of the quality control problem that preserves privacy of workers. We propose a worker-private latent class protocol where a requester can estimate the true results with worker privacy preserved. The key ideas are decentralization of computation and introduction of secure computation. We theoretically guarantee the security of the proposed protocol and experimentally examine the computational efficiency and accuracy.