Synthesis of Network Biobased Aliphatic Polyesters Exhibiting Better Tensile Properties than the Linear Polymers by ADMET Polymerization in the Presence of Glycerol Tris(undec-10-enoate).

Development of biobased aliphatic polyesters with better mechanical (tensile) properties in film has attracted considerable attention. This report presents the synthesis of soluble network biobased aliphatic polyesters by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enyl)isosorbide diester [M1, dianhydro-D-glucityl bis(undec-10-enoate)] in the presence of a tri-arm crosslinker [CL, glycerol tris(undec-10-enoate)] using a ruthenium-carbene catalyst, and subsequent olefin hydrogenation using RhCl(PPh3)3. The resultant polymers, after hydrogenation (expressed as HCP1) and prepared in the presence of 1.0 mol% CL, showed better tensile properties than the linear polymer (HP1) with similar molecular weight [tensile strength (elongation at break): 20.8 MPa (282%) in HP1 vs. 35.4 MPa (572%) in HCP1]. It turned out that the polymer films prepared by the addition of CL during the polymerization (expressed as a 2-step approach) showed better tensile properties. The resultant polymer film also shows better tensile properties than the conventional polyolefins such as linear high density polyethylene, polypropylene, and low density polyethylene.

Synthesis of High Molecular Weight Biobased Aliphatic Polyesters Exhibiting Tensile Properties Beyond Polyethylene.

Synthesis of high molecular weight polyesters prepared by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enoate) with isosorbide (M1), isomannide (M2), and 1,3-propanediol (M3) and the subsequent hydrogenation have been achieved by using a molybdenum-alkylidene catalyst. The resultant polymers (P1) prepared by the ADMET polymerization of M1 (in toluene at 25 °C) possessed high Mn values (Mn = 44400-49400 g/mol), and no significant differences in the Mn values and the PDI (Mw/Mn) values were observed in the samples after the hydrogenation. Both the tensile strength and the elongation at break in the hydrogenated polymers from M1 (HP1) increased upon increasing the molar mass, and the sample with an Mn value of 48200 exhibited better tensile properties (tensile strength of 39.7 MPa, elongation at break of 436%) than conventional polyethylene, polypropylene, as well as polyester containing C18 alkyl chains. The tensile properties were affected by the diol segment employed, whereas HP2 showed a similar property to HP1.

Effect of disclosing the relation between effort and unit reliability on system reliability: An economic experiment.

The purpose is to experimentally examine the effect of disclosing the risk probability of each unit in a production system on human behavior and the resulting system reliability. We used an economic experiment based on the theoretical model of Hausken (2002) to evaluate the effect of disclosing the relation between effort and unit reliability. We conducted first the non-disclosed-risk experiment and then the disclosed-risk experiment within subjects in both series and parallel systems. Our experimental results show that disclosing the relation between effort and unit reliability has two positive effects. First, subjects succeeded in improving the system reliability while cutting back on efforts to reduce the risk of their units when the risk probability was disclosed. In each system, the disclosed-risk condition achieves significantly higher system reliability on average than does the non-disclosed-risk condition, although the average level of effort is significantly lower under the disclosed-risk condition than under the non-disclosed-risk condition. Second, disclosing the risk probability simplified the subjects' decision-making process and reduced its cost because subjects made their decisions on the amount of effort to exert based only on the risk probability information without considering other factors, such as the number of accidents.

Development of a fluorescent protein-antibody Förster resonance energy transfer probe for the detection and imaging of osteocalcin.

Fluorescence-based biosensor probes, especially those based on Förster resonance energy transfer (FRET) between fluorescent protein (FP) variants, are widely used to monitor various biological phenomena, often detecting ligand-induced association of the receptor domains. While antibodies are fertile sources of specific receptors for various biomolecules, their potential has not been fully exploited. In this study, we used a fluorescent probe comprising FP-fused antibody variable region fragments to detect a bone metabolism biomarker, osteocalcin (BGP), by using fluorescence spectrometry/microscopy. Because the association between the two proteins increases in the presence of antigen BGP or its C-terminal peptide, the increased antigen in a sample can be monitored as a FRET efficiency increase, based on the open sandwich fluoroimmunoassay principle. The results clearly indicated that the FP-antibody FRET probe could be used as a diagnostic reagent to measure levels of BGP in the clinically relevant concentration range and to image BGP produced from live osteoblast cells.

Open flower fluoroimmunoassay: a general method to make fluorescent protein-based immunosensor probes.

Fluorescence-based probes, especially those that utilize Förster resonance energy transfer (FRET) between fluorescent protein (FP) variants, are widely used to monitor various biological phenomena, most often detecting its ligand-induced conformational change through the receptor domain. While antibody provides a fertile resource of a specific receptor for various biomolecules, its potential has not been fully exploited. An exception is a pair of donor FP-fused VH and acceptor FP-fused VL fragments, which has been proven useful when their association increases in the presence of antigen (open sandwich fluoroimmunoassay, OS-FIA). However, probes for larger proteins such as serum albumin (SA) were difficult to produce, since the interaction between VH and VL of these antibodies is barely affected by the bound antigen. Here, we propose a novel strategy, called open flower fluoroimmunoassay (OF-FIA), using a probe composed of a donor-fused VH and an acceptor-fused VL linked by a disulfide bond between VH and VL (CyPet/YPet-dsFv). The probe gave high FRET efficiency due to the dimerization propensity of the FP pair, while the efficiency got lower as SA concentration increased, probably due to dimer disruption. The constructed probe could detect clinically relevant range of SA, showing its potential as a diagnostic reagent.

Estimating health risk from exposure to 1,4-dioxane in Japan.

Exposure to 1,4-dioxane from the atmosphere around high-emission plants and from consumer products used in daily life that contain the substance may have adverse health effects; however, its emission into the atmosphere is not regulated. In this study, the health risk posed by 1,4-dioxane is assessed to investigate whether measures should be undertaken to reduce exposure to 1,4-dioxane. The notion of the margin of exposure (MOE), given by the ratio of no observed adverse effect level (NOAEL) to actual or projected exposure level, is used to assess risk. In exposure assessment, two types of exposure channel are considered: (a) the use of consumer products that contain 1,4-dioxane and (b) the inhalation of air around high-emission plants. To estimate exposure via channel (a), we measured the concentration of 1,4-dioxane in consumer products and estimated the interindividual variability of exposure by Monte Carlo simulation that reflects the measured data. To estimate exposure via channel (b), we employed a local-level atmospheric dispersion model to estimate the concentration of 1,4-dioxane immediately around high-emission plants. For hazard assessment, we derived the inhalatory and oral NOAELs for liver adenomas and carcinomas and the uncertainty factor. The results suggest that measures are not needed to reduce exposure to 1,4-dioxane from consumer products. As for inhalation exposure around high-emission plants, some residents may be exposed to health risks if certain conservative analytical conditions are assumed. Even in this case, we conclude that it is not necessary for Plant A to stop the use of 1,4-dioxane immediately and that medium- to long-term emission reduction measures should be sufficient.