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.     

Low-Temperature Synthesis of ZrC Powder by Cyclic Reaction of Mg in ZrO2–Mg–CH4

We investigated the conditions for low-temperature synthesis of ZrC fine powder from ZrO₂–Mg–CH₄. The synthesis utilizes a thermite-type reaction, with Mg as the reducing agent, and a reaction between Mg and CH₄ gas as a carbon source. The Mg/ZrO₂ molar ratio as well as the heating rate were varied. Because C can be continuously fed into the reaction group by the cyclic reaction of Mg through the formation and decomposition of Mg₂C₃ (2Mg + 3CH₄→ Mg₂C₃+ 6H₂→ 2Mg + 3C), a molar ratio of 2.2 for Mg/ZrO₂ was sufficient for the synthesis of single-phase ZrC. ZrC powders were synthesized under the following conditions: Mg/ZrO₂ molar ratio = 2.2, heating rate = 20°C/min, and temperature maintained at 750°C for 30 min. The amount of reaction heat produced in the reduction reaction of ZrO₂ by Mg depended on the Mg/ZrO₂ molar ratio, specifically, the amount of ZrO₂ contained. Moreover, the cyclic reaction of Mg-Mg₂C₃–Mg was influenced by the amount of reaction heat described above and by the heating rate. The ZrC fine powder showed little aggregation and high dispersibility.     

Synthesis and Magneto-mechanical Properties of Ce-TZP/La M-Type Hexaferrite Composite

An in situ composite composed of ceria-stabilized tetragonal zirconia polycrystals (Ce-TZP) and La{Co_0.5Fe_0.5(Fe_0.9Al_0.1)₁₁}O₁₉ was synthesized from a powder mixture of Ce-TZP, La(Fe_0.9Al_0.1)O₃, Fe₂O₃, Al₂O₃, and CoO. The dense Ce-TZP dispersed with platelike La{Co_0.5Fe_0.5(Fe_0.9Al_0.1)₁₁}O₁₉ crystals as a second phase were formed after sintering from 1250° to 1350°C. The saturation magnetization of the in situ composite Ce-TZP/La{Co_0.5Fe_0.5(Fe_0.9Al_0.1)₁₁}O₁₉ was proportional to the mass fraction of the hexaferrite second phase in Ce-TZP. The coercivity of the composite with a 20 mass% of second phase decreased from 9.14 to 2.52 kOe (from 728 to 201 kA/m) after the pulverization of the composite. The susceptibility (χ) increased by 15%–25% under uniaxial stress on the composite. The change of the susceptibility (Δχ/χ) value increased with decreasing the mass fraction of the second phase in the composite. The Δχ was found to increase linearly with applied stress and abruptly change on cracking, which is expected for the application in fracture sensing of the composite.     

Selective detection of acetylene gas extracted from isolation oil by an electrochemical sensor using a gold electrode

The selective detection of acetylene in gases extracted from isolation oils has been studied to develop an electrochemical sensor for the diagnostic monitoring of the condition of in-service electrical instruments. Effects of coexisting gases (CH₄, C₂H₆, C₂H₄, H₂ and CO) on the oxidation current of C₂H₂ were tested using gas-permeable gold-coated and platinum-black electrodes as the sensor. The gold-coated electrode showed good behaviour for the selective current detection of acetylene under potentiostatic conditions (−0.1 V/Pt-black reference electrode) in 10m H₂SO₄ electrolyte solution.     

Electroless copper plating using Fe as a reducing agent

Although the electroless plating method is known to be an effective method for obtaining fine wiring in particular, 1 mol hydrogen gas is generated during 1 mol Cu deposition, and voids are generated in the wiring when electroless Cu plating is applied to fine wiring. To avoid the hydrogen evolution, the possibility of performing electroless Cu plating was confirmed using an inexpensive Fe^II compound as a reducing agent. The bath contains CuSO₄, FeSO₄, NaCl, ethylenediamine, sodium citrate, polyethylene glycol (PEG), and 2,2′-bipyridine. Under optimal conditions, over 1.7 μm of copper deposit with a smooth surface was obtained after 3 h of plating, which did not contain iron as an impurity. The electrical resistivity of the copper film is about 3-4 μΩ cm corresponding to that of electroplated copper films.