Climate Change Implications of Bio-Based and Marine-Biodegradable Plastic: Evidence from Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), PHBH or PHBHHx, is a novel bio-based polymer that is biodegradable in both soil and marine environments. While bio-based and biodegradability are often celebrated features to mitigate environmental problems of plastics, their life cycle environmental impacts contain uncertainties that are yet to be fully understood. To develop effective introduction schemes for PHBH, this study assessed the life cycle climate change implications of PHBH. We computed the life cycle greenhouse gas emissions (GHG) and fossil resource consumption of produce bags and spoons composed of PHBH and their fossil-based alternatives based on industrial-scale data. The products were assessed against 10 end-of-life scenarios for commercial plastics. As a result, the cradle-to-gate GHG of PHBH ranged between 0.32 and 16.5 kgCO2e/kg-PHBH depending on the land-use change assumed for the biomass production. The product-based comparative analysis presented that PHBH spoons have lower cradle-to-grave GHG emissions over their fossil-based alternatives but not with produce bags because PHBH spoons have a smaller GHG per functional unit than that of its fossil counterpart. The end-of-life scenario analysis conveyed that PHBH should be introduced to a region with a plastic waste management system that avoids methane generation and facilitates energy recovery.

Thermal Mode Spectroscopy for Thermal Diffusivity of Millimeter-Size Solids.

Heat conduction possesses (thermal) modes in analogy with acoustics even without oscillation. Here, we establish thermal mode spectroscopy to measure the thermal diffusivity of small specimens. Local heating with a light pulse excites such modes that show antinodes at the heating point, and photothermal detection at another antinode spot allows measuring relaxation behavior of the desired mode selectively: The relaxation time yields thermal diffusivity. The Ritz method is proposed for arbitrary geometry specimens. This method is applicable even to a diamond crystal with ∼1 mm dimensions.

Benchmarking Performance Indices of Electrochemical CO2 Reduction to Ethylene Based on Prospective Life Cycle Assessment for Negative Emissions.

To mitigate global warming to the most ambitious targets, it is necessary to remove CO2 from the atmosphere and reduce fossil fuels use. The electrochemical conversion of CO2 to ethylene (C2H4) as a basic chemical is a promising technology that meets both requirements; however, its life cycle CO2 emissions remain inconclusive because of varying assumptions in the performance indices. This study aimed to set benchmarks for the four most sensitive indices to achieve -0.5 t-CO2/t-C2H4 by calculating net greenhouse gas (GHG) emissions through a prospective life cycle assessment of a model system including CO2 capture, CO2 enrichment, electrochemical conversion, CO2 recycling, and cryogenic separation. As a result, the electrochemical conversion process was the hotspot of life cycle emissions, and representative benchmarks were determined as follows: cell voltage, 3.5 V; C2H4 Faraday efficiency, 70%; conversion rate, 20%; and electrochemical CO2 recycling energy, 2.2 GJ/t-CO2. The gaps between the benchmarks and current top data of cell voltage and Faraday efficiency were <10%, and suppressing the performance degradation for up to one year was found to be a critical requirement. These results can direct research towards the development of a year-round stable system, rather than further improving the performance indices.

Monitoring and analysis of solvent emissions from metal cleaning processes for practical process improvement.

OBJECTIVES: Industrial cleaning processes are a major source of emissions of chlorinated organic solvents in Japan. Solvent emission mechanisms from metal cleaning processes were analysed to support process improvement aimed at emission reductions. METHODS: The amounts of solvents directly emitted from a washing machine and solvents taken out by metal parts to be cleaned were measured in laboratory experiments using an industrial washing machine. Direct emissions to a local ventilation system and to the workplace were analysed, while several process conditions were changed. The drying rate of solvents on surfaces was analysed for seven metal parts to clarify the effects of their materials and shape. RESULTS: The results for direct solvent emissions show that solvents emitted because of the movement of metal parts inside a washing machine can be mainly exhausted through a local ventilation system, while the operation of an ultrasonic device can increase solvent diffusion to the workplace. Lowering the cooling water temperature can be effective in avoiding such solvent diffusion to the workplace. The results also show that the heat capacity and shape complexity of metal parts can affect the drying rate of solvents on their surfaces. CONCLUSIONS: Analysis of the results shows the effectiveness of using a local ventilation system and cooling pipes in controlling solvent emissions for several work tasks. The minimum time required to dry all solvents on the surface of metal parts was also estimated. Analyses of the emission mechanisms in this study clarified the major factors in solvent emissions and the effectiveness of process modifications for emission reductions. The findings are applicable to practical process improvement aimed at emission reductions in cleaning sites.

Seed-dependent deposition behavior of Aß peptides studied with wireless quartz-crystal-microbalance biosensor.

Real-time monitoring of the deposition processes of Aß1-40 and Aß1-42 peptides on various seeds has been performed using a 55 MHz wireless quartz-crystal microbalance (QCM) over long-time periods (~40 h). Dissolved peptide solutions were stirred for nucleation and growth of seeds at pH = 7.4 and 4.6, which were immobilized on the sensor chips. The isolated Aß peptides were then flowed at the neutral pH, focusing on the interaction between the seeds and the monomers (or small multimers), excluding other interactions among seeds and other aggregates. The thioflavin-T fluorescence assay and atomic-force microscopy were used for evaluating structures of the seeds and deposited aggregates. The deposition rate, determined by the frequency decrease, is about 100 monomers/nm(2)/year in the case of fibril formation. The notable deposition behavior was observed in the deposition of Aß1-40 peptide on Aß1-42 seeds grown at the lower pH, which can be an important model for Alzheimer's disease.

Multichannel wireless-electrodeless quartz-crystal microbalance immunosensor.

We develop the wireless-electrodeless multichannel quartz-crystal microbalance (QCM) biosensor using quartz plates of slightly different thicknesses. Their shear vibrations are simultaneously excited and detected by a pair of antenna wires to perform the noncontacting measurement. Their fundamental resonance frequencies are between 43 and 55 MHz, and vibrations at up to 10 channels are measured in liquids. Owing to high affinity of naked quartz surfaces for proteins, we immobilized various receptor proteins on different quartz plates nonspecifically and detected various antigen-antibody reactions separately. The exponential coefficient of the frequency change, rather than the amount of the frequency decrease, is found to be useful for distinguishing between specific and nonspecific binding reactions.

Replacement-free electrodeless quartz crystal microbalance biosensor using nonspecific-adsorption of streptavidin on quartz.

This paper proposes a replacement-free and surface-modification-free quartz crystal microbalance (QCM) biosensor. With the use of significant nonspecific adsorption of streptavidin on naked quartz surfaces, target analyte is detected through biotin-tagged receptors on streptavidin. The wireless-electrodeless QCM technique is developed with a 30 microm thick AT-cut quartz plate, whose fundamental resonance frequency is 55 MHz, and the naked quartz surfaces are used for the nonspecific adsorption of streptavidin. Once it is installed in the sensor cell, it can be used semipermanently; it never needs to be replaced. The equilibrium dissociation constant of streptavidin on quartz is determined to be 1.3 x 10(-7) M. The flow rate affected the number of the adsorbed streptavidin on quartz as well as the binding velocity.

170-MHz electrodeless quartz crystal microbalance biosensor: capability and limitation of higher frequency measurement.

We develop a highly sensitive quartz crystal microbalance (QCM) biosensor with a fundamental resonance frequency of 170 MHz. A naked AT-cut quartz plate of 9.7 microm thick is set in a sensor cell. Its shear vibration is excited by the line wire, and the vibration signals are detected by the other line wire, achieving the noncontacting measurement of the resonance frequency. The mass sensitivity of the 170 MHz QCM biosensor is 15 pg/(cm2 Hz), which is better than that of a conventional 5 MHz QCM by 3 orders of magnitude. Its high sensitivity is confirmed by detecting human immunoglobulin G (hIgG) via Staphylococcus protein A immobilized nonspecifically on both surfaces of the quartz plate. The detection limit is 0.5 pM. Limitation of the high-frequency QCM measurement is then theoretically discussed with a continuum mechanics model for a plate with point masses connected by elastic springs. The result indicates that a QCM measurement will break down at frequencies one-order-of-magnitude higher than the local resonance frequency at specific binding cites.

Effects of flow rate on sensitivity and affinity in flow injection biosensor systems studied by 55-MHz wireless quartz crystal microbalance.

In this paper, we developed a 55-MHz wireless-electrodeless quartz crystal microbalance (QCM) and systematically studied the effects of flow rate on the sensitivity to the detection of proteins and on the affinity between biomolecules evaluated by the flow injection system. Brownian motion of proteins in liquid suggests a low probability of meeting, and the convection effect plays an important role in the sensitivity and the affinity in the flow cell injection system. The wireless quartz crystal was isolated in the QCM cell, and flow rates between 50 and 1000 microL/min were used for monitoring binding reactions between human immunoglobulin G and Staphylococcus aureus protein A. The sensitivity was significantly increased as the flow rate increased, while the affinity value remained unchanged. However, the affinity value was affected by the reaction time for a large-concentration analyte, indicating the need of a high-sensitivity biosensor system for accurate evaluation of affinity. The electrode effect on the QCM sensitivity was also theoretically investigated, showing that the electrode significantly deteriorates the QCM sensitivity and makes the Sauerbrey equation invalid.

A freestanding oscillator for resonant-ultrasound microscopy.

Resonant-ultrasound microscopy with a freestanding rod oscillator has been developed for mapping a material's elastic properties in a localized surface region, for the purpose of evaluating elastic stiffness through the resonance frequency of the oscillator contacting the specimen by its tip. A stronger biasing static magnetic field makes the ferritic steel oscillator plumb without any other mechanical support except tip-sample contact. For a noncontacting acoustical coupling, the longitudinal vibration of the oscillator is excited and detected with a surrounding solenoid coil by the magnetostrictive effect. This freestanding configuration realizes only a mechanical "point" contact between the oscillator and the sample surface, which yields accurate measurement of the local elastic stiffness. As an illustrated example, the new microscopy method is applied to an SCS- 6 SiCf/Ti-6Al-4V composite to visualize its elastic-stiffness distribution.

Design-oriented regression models for H2O2 decontamination processes in sterile drug product manufacturing considering rapidity and sterility.

We developed regression models for designing rapid and effective H2O2 decontamination processes in the manufacturing of sterile drug products such as injectables. Decontamination, which is typically performed by using H2O2, is a critical changeover process used to establish a sterile environment for filling products. In the process, there is a trade-off relationship between the duration of the process and the level of sterility assurance that needs to be considered in the design. Our model defines these two items as objective functions and the parameters describing the profile of H2O2 injection and the initial humidity as design variables. Our model also considers aeration, i.e., removal of H2O2 from the environment, as a part of the entire process. This design-oriented modeling considering the entire process is the novelty of the work. Experiments were performed using an industrial isolator to develop and validate a set of regression models that describe the relationship between the design variables and the objective functions. In the application of the model, Pareto-optimal conditions could be indicated given the target H2O2 concentration in aeration, which is useful for the makers of drugs and/or isolators for designing decontamination processes.

Concentration dependence of IgG-protein A affinity studied by wireless-electrodeless QCM.

The binding affinity between human immunoglobulin G (IgG) and protein A was studied by the homebuilt wireless-electrodeless quartz crystal microbalance (QCM). Protein A was immobilized on the electrodeless AT-cut quartz plate of 0.05 mm thick and its fundamental resonance frequency near 34 MHz was measured by a noncontacting manner using a line antenna. The vibrational analysis was performed to ensure higher sensitivity of the electrodeless QCM. A flow-cell system was fabricated to continuously measure the resonance frequency during the injection sequence of the IgG solutions with concentrations of 1-20,000 ng/mL. The exponential frequency changes were recorded to determine the affinity based on the Langmuir kinetics. The equilibrium constant K(A) significantly varied between 6 x 10(6) and 6 x 10(10) M(-1), depending on the IgG concentration, which is attributed to various formations of IgG-protein A complexes.

Imaging of local stiffness of damaged polycrystalline copper: nondestructive evaluation by resonance ultrasound microscopy.

The distribution of the local stiffness of a polycrystalline copper exposed to a creep test was studied by resonance ultrasound microscopy. The local effective modulus was evaluated from the resonance frequency of the isolated langasite oscillator touching the specimen. Defects appeared predominantly on grain boundaries, and they were clearly visualized by the stiffness microscopy through the significant decrease of the effective stiffness. The stiffness within the grains becomes lower regardless of invisible defects. The stiffness distribution was quantitatively analyzed by the contact model between two anisotropic bodies and by the micromechanics modeling. The microscopic stiffness shows much higher sensitivity to the defects than the macroscopic stiffness.

Accelerated crystallization of colloidal glass by mechanical oscillation.

Crystallization of a hard-sphere colloidal glass by mechanical oscillation is investigated, and accelerated crystallization is found at a specific frequency. The crystallization frequency increases as attractive force between particles increases, indicating that interparticle interaction affects the crystallization frequency. Time scale of the mechanical oscillation is different from that of the slow relaxation, and notable relationship with the low-frequency mode is not observed. The experimental results are not explained by the previously proposed model for crystallization by oscillatory shear. Conversely, we speculate that activations of the fast relaxation and particle motion in crystal-like clusters are possible causes of the observations.

Drastic acceleration of fibrillation of insulin by transient cavitation bubble.

Amyloid-fibril formation of proteins can be accelerated by ultrasonic irradiation to the peptide solutions. Although this phenomenon contributes to understanding pathogenic behavior of amyloidosis, its physical mechanism has not been clarified, because several factors (cavitation, temperature increase, stirring effect, and so on) related to ultrasonic irradiation can participate in the fibrillation reaction. Here, we independently study contributions of the possible factors, using insulin, which is extremely stable and then suitable for the mechanism clarification. We find that the optimized ultrasonic irradiation can drastically accelerate the fibrillation reaction; the time for completing the reaction is shortened compared with the high-speed (1200rpm) stirring agitation by a factor of 430. The fibrillation reaction proceeds only when the subharmonic-mode intensity exceeds a threshold, indicating generation of the transient cavitation bubbles. Our results reveal that not the temperature increase but the transient cavitation bubbles work as the dominant accelerator of the fibrillation reaction.

Optimized Ultrasonic Irradiation Finds Out Ultrastable Aß1-40 Oligomers.

Oligomer species of amyloid ß (Aß) peptides are intensively investigated because of their relevance to Alzheimer's disease (AD), and a stable oligomer will be a cause of AD. In this article, we investigate the structural stability of two representative Aß1-40 oligomers, which are with and without the ß-sheet structure, denoted by ß and non-ß oligomers, respectively, using optimized ultrasonic irradiation (OUI). Recent studies reveal that OUI significantly accelerates the fibril formation in Aß1-40 monomers; it is capable of transforming any unstable oligomers into fibrils (the dead-end products) in a short time. First, we find that ß oligomers can be produced under high-speed stirring agitation; their ß-sheet structures are evaluated by the circular-dichroism spectrum measurement, by the immunoassay using the fibril-specific OC antibody, and by the seeding experiment, showing identical characteristics to those formed in previous reports. Second, we form non-ß oligomers in a high-concentration NaCl solution and confirm that they include no ß-sheet structure, and they are recognized by the oligomer-specific A11 antibody. Furthermore, we confirm the neurotoxicity of the two types of oligomers using the neural tissue derived from mouse embryonic stem cells. We apply the OUI agitation to the ß and non-ß oligomers. The non-ß oligomers are transformed into the fibrils, indicating that they are intermediate species in the fibrillation pathway. However, the ß oligomers are surprisingly unaffected by OUI, indicating their high thermodynamic stability. We conclude that the ß oligomers should be the independent dead-end products of another pathway, different from the fibrillation pathway.

Evaluating nanotechnology opportunities and risks through integration of life-cycle and risk assessment.

It has been some 15 years since the topics of sustainability and nanotechnologies first appeared together in the scientific literature and became a focus of organizations' research and policy developments. On the one hand, this focus is directed towards approaches and tools for risk assessment and management and on the other hand towards life-cycle thinking and assessment. Comparable to their application for regular chemicals, each tool is seen to serve separate objectives as it relates to evaluating nanotechnologies' safety or resource efficiency, respectively. While nanomaterials may provide resource efficient production and consumption, this must balance any potential hazards they pose across their life-cycles. This Perspective advocates for integrating these two tools at the methodological level for achieving this objective, and it explains what advantages and challenges this offers decision-makers while highlighting what research is needed to further enhance integration.

Wireless electrodeless piezomagnetic biosensor with an isolated nickel oscillator.

This study presents a fundamental concept of piezomagnetic biochemical sensor driven in a wireless-electrodeless manner. A stepped cylindrical rod of nickel is used as the oscillator, which traps the vibrational energy of axially-polarized surface-shear waves in the central part, where the diameter is slightly larger. A meander-line coil surrounding the oscillator with an air gap can cause and detect the resonant vibrations of the surface-shear waves via the piezomagnetic effect. The resonant frequency of the trapped-mode resonance is continuously measured to detect human immunoglobulin G (IgG). It decreased by 0.08% when a solution containing IgG was injected into the glass cell where the oscillator was placed alone. This oscillator is useful for fundamental studies of various biochemical reactions in a closed system in different environmental gases and different pressures.

Nucleus factory on cavitation bubble for amyloid ß fibril.

Structural evolution from monomer to fibril of amyloid ß peptide is related to pathogenic mechanism of Alzheimer disease, and its acceleration is a long-running problem in drug development. This study reveals that ultrasonic cavitation bubbles behave as catalysts for nucleation of the peptide: The nucleation reaction is highly dependent on frequency and pressure of acoustic wave, and we discover an optimum acoustical condition, at which the reaction-rate constant for nucleation is increased by three-orders-of magnitudes. A theoretical model is proposed for explaining highly frequency and pressure dependent nucleation reaction, where monomers are captured on the bubble surface during its growth and highly condensed by subsequent bubble collapse, so that they are transiently exposed to high temperatures. Thus, the dual effects of local condensation and local heating contribute to dramatically enhance the nucleation reaction. Our model consistently reproduces the frequency and pressure dependences, supporting its essential applicability.