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Transport of material across liquid interfaces is ubiquitous for living cells and is also a crucial step in drug delivery and in many industrial processes. The fluids that are present on either side of the interfaces will usually have different viscosities. We present a physical model for the dynamics of microswimmers near a soft and penetrable interface that we solve using computer simulations of Navier–Stokes flows. The literature contains studies of similar isoviscous fluid systems, where the two fluids have the same viscosity. Here, we extend this to the more general case where they have different viscosities. In particular, we investigate the dynamics of swimmers approaching a fluid–fluid interface between phase-separated fluids with distinct viscosities. We find that the incoming angle, viscosity ratio, and swimming type (i.e., pusher, puller, or neutral) strongly influence the collision, resulting in four distinct dynamical modes: bouncing, sliding, penetrating, and hovering. The former three modes are also observed for isoviscous systems, while the hovering, in which strong pullers swim parallel to the interface at a non-zero distance, requires mismatched viscosities. Furthermore, swimmers exhibit a preference for lower viscosity fluids, known as viscotaxis. This implies that, for a wide distribution of contact angles, more swimmers will transition into the low-viscosity environment than vice versa. Consequently, a swimmer starting in a low-viscosity fluid is more likely to bounce back at the interface, while a swimmer in a high-viscosity fluid is more likely to penetrate the interface and enter the lower viscosity fluid.

The international issue to be addressed towards realizing a low-carbon society is to reduce the amount of carbon-based underground reserves such as coal, petroleum, and coke, and strongly encouraged to use carbon neutral biomass-derived resources. Woodceramics is a hybrid porous carbon material composed of wood-based biomass and phenolic resin, characterized by high far-infrared emissivity and large specific surface area. Woodceramics has been studied as heating elements and humidity and gas sensors, etc. If this is applied to the inner walls of aging and grain drying furnaces for vegetables and fruits, both ripening and drying are greatly promoted and fossil fuels used in boilers can be significantly reduced. In fact, it can produce black garlic with far infrared rays using a woodceramics brick efficiently. Furthermore, as a substitute for phenolic resin, if plant-based liquefied materials from cashew nut shell oil can be prepared and can be used for manufacturing woodceramics, then all carbon neutral circulating woodceramics made from wood-based biomass is possible to manufacture. On the other hand, woodplastics is a composite material that can be made of wooden materials and plastics, and able to expect the effective use of wood-based biomass and waste plastics.

Dynamic heterogeneity is expected to be a key concept for understanding the origin of slow dynamics near the glass transition. In previous studies, quantitative evaluations of dynamic heterogeneity have been attempted using two different routes, i.e., the speckle patterns in scattering experiments or the four-body correlation functions of microscopic configuration data obtained from molecular dynamics simulations or real-space observations using confocal microscopy. However, the physical relationship between these dynamic heterogeneities obtained using different methods has not been clarified. This study proposes a connection between dynamic heterogeneities characterized based on speckle patterns and those obtained from four-body correlations. The validity of the relationship is also clarified., Comment: 6 pages, 5 figures

Few simulations exist for microswimmers near deformable interfaces. Here, we present numerical simulations of the hydrodynamic flows associated with a single microswimmer embedded in a binary fluid mixture. The two fluids demix, separated by a penetrable and deformable interface that we assume to be initially prepared in its planar ground-state. We find that the microswimmer can either penetrate the interface, move parallel to it or bounce back off it. We analyze how the trajectory depends on the swimmer type (pusher/puller) and the angle of incidence with respect to the interface. Our simulations are performed in a system with periodic boundary conditions, corresponding to an infinite array of fluid interfaces. A puller reaches a steady state in which it either swims parallel to the interface or selects a perpendicular orientation, repeatedly penetrating through the interface. In contrast, a pusher follows a bouncing trajectory between two interfaces. We discuss several examples in biology in which swimmers penetrate soft interfaces. Our work can be seen as a highly simplified model of such processes.

The mechanosensitivity of cells, which determines how they are able to respond to mechanical signals received from their environment, is crucial for the functioning of all biological systems. In experiments, cells placed on cyclically stretched substrates have been shown to reorient in a direction that depends not only on the type of cell, but also on the mechanical properties of the substrate, and the amplitude and rate of stretching. However, the underlying biochemical and mechanical mechanisms responsible for this realignment are still not completely understood. In this study, we introduce a computational model for fast crawling on cyclically stretched substrates that accounts for the sub-cellular processes responsible for the cell shape and motility, as well as the coupling to the substrate through the focal adhesion sites. In particular, we focus on the role of the focal adhesion dynamics, and show that the reorientation under cyclic stretching is strongly dependent on the frequency, as has been observed experimentally. Furthermore, we show that an asymmetry during the loading and unloading phases of the stretching, whether coming from the response of the cell itself, or from the stretching protocol, can be used to selectively align the cells in either the parallel or perpendicular directions., Comment: 19 pages, 7 figures

Three-dimensional simulations with fully resolved hydrodynamics are performed to study the dynamics of a single squirmer under gravity, in order to clarify its motion in the vicinity of a flat plate. Different dynamics emerge for different gravity strengths. In a moderate gravity regime, neutral squirmers and pullers eventually stop moving and reorient in a direction perpendicular to the plate; pushers, instead, exhibit continuous motion in a tilted direction. In the strong gravity regime, all types of squirmers sediment and reorient perpendicularly to the plate. In this study, the chirality is introduced to model realistic micro-swimmers, and its crucial effects on the swimmer dynamics are presented., 8 pages, 6 figures

The attachment of solid particles to the surface of immersed gas bubbles plays a fundamental role in surface science, and hence plays key roles in various engineering fields ranging from industrial separation processes to the fabrication of functional materials. However, detailed investigation from a microscopic view on how a single particle attaches to a bubble surface and how the particle properties affect the attachment behavior has been so far scarcely addressed. Here, we observed the attachment of a single particle to a bubble surface using a high-speed camera and systematically investigated the effects of the wettability and shape of particles. We found that hydrophobic particles abruptly "jumped into" the bubble while sliding down the bubble surface to eventually satisfy their static contact angles, the behavior of which induced a much stronger attachment to the bubble surface. Interestingly, the determinant factor for the attachment efficiency of spherical particles was not the wettability of the spherical particles but the location of the initial collision with the bubble surface. In contrast, the attachment efficiency of anisotropically-shaped particles was found to increase with the hydrophobicity caused by a larger contact area to the bubble surface. Last but not least, a simple formulation is suggested to recover the contact angle based on the jump-in behavior.

The smoothed profile method is extended to study the rheological behaviour of colloidal dispersions under shear flow by using the Lees–Edwards boundary conditions. We start with a reformulation of the smoothed profile method, a direct numerical simulation method for colloidal dispersions, so that it can be used with the Lees–Edwards boundary condition, under steady or oscillatory-shear flow. By this reformulation, all the resultant physical quantities, including local and total shear stresses, become available through direct calculation. Three simple rheological simulations are then performed for (1) a spherical particle, (2) a rigid bead chain and (3) a collision of two spherical particles under shear flow. Quantitative validity of these simulations is examined by comparing the viscosity with that obtained from theory and Stokesian dynamics calculations. Finally, we consider the shear-thinning behaviour of concentrated colloidal dispersions.

Hydrodynamics of rod-like particles, found extensively in the chemical and process industry, is investigated here, using direct numerical simulations. A recently developed formulation of the smoothed profile method for rigid bodies is first validated for rod-like particles (rods) and then used to characterize the concentration effects on the static and dynamic properties of rods in the Stokes regime. Normalized drag and lift coefficients of a single rod of aspect ratio 3 and 4, followed the well known sin2θ and sin θ cos θ curves against the incident angle (θ), respectively. We found significant inhomogeneity in the microstructure of the settling rods. These inhomogeneties, cause the formation of clusters, even at low volume fractions. These clusters move as a large lump, inducing pronounced hydrodynamic interactions, which have significant effects on the settling system. The average settling velocity normalized by the terminal velocity of an isolated rod, shows a non-monotonic behavior; increasing at low concentration because of the cluster formation in which rod packets settle faster than an isolated rod, and decreasing at high concentration because of many particle interactions. Furthermore, velocity fluctuations are larger than those of spherical particles because of the cluster formation. Histogram of particles’ orientation angle shows that the majority of the particles are vertically aligned.

The capillary-induced bending of flexible fibres, a process also known as elasto-capillary deformation, is central to a variety of industrial and non-industrial applications, among which stand out textile flotation, stabilization of emulsions, micro-folding of elastic structures, and clogging of feather fibres by oil droplets. A consistent formulation for the direct numerical simulation of a flexible fibre interacting with a fluidic interface is presently suggested. The fibre is geometrically decomposed into a chain of spherical beads, which undergo stretching, bending, and twisting. interactions. The capillary force, acting at the three-phase contact line, is calculated using a ternary diffuse-interface model. In a first stage, the fibre deformation model and the ternary diffuse-interface model are validated against theoretical solutions. In a second stage, the two- and three-dimensional elasto-capillary bending of a fibre by an immersed droplet are numerically investigated. Partial wrapping and complete encapsulation could be simulated. The results show that the fibre curvature increases linearly with the square of the elasto-capillary length, for both low and large structural deformation.

The migration of cells is relevant for processes such as morphogenesis, wound healing, and invasion of cancer cells. In order to move, single cells deform cyclically. However, it is not understood how these shape oscillations influence collective properties. Here we demonstrate, using numerical simulations, that the interplay of directed motion, shape oscillations, and excluded volume enables cells to locally "synchronize" their motion and thus enhance collective migration. Our model captures elongation and contraction of crawling ameboid cells controlled by an internal clock with a fixed period, mimicking the internal cycle of biological cells. We show that shape oscillations are crucial for local rearrangements that induce ordering of neighboring cells according to their internal clocks even in the absence of signaling and regularization. Our findings reveal a novel, purely physical mechanism through which the internal dynamics of cells influences their collective behavior, which is distinct from well known mechanisms like chemotaxis, cell division, and cell-cell adhesion.

A triptycene-based shape-persistent belt-shaped macrocycle, metallonanobelt, was synthesized by the self-assembly of 2,3,6,7-tetraaminotriptycene L and square planar Pd2+. The pentamer was selectively formed by the complexation of L with Pd2+ in the presence of the pillar[6]arene derivative P6 having triethylene glycol pendant as a template, whereas a mixture of a trimer, tetramer, and pentamer was obtained in the absence of the template. The pentamer was successfully isolated based on the solubility difference between the metallonanobelt and the template. It was also revealed that the isolated pentamer was remarkably stable in solutions such as acetonitrile or methanol thanks to the relatively inert planar chelate metal complex, [Pd(o-phenylenediamine)2] unit. Thus, we can handle the metallonanobelt almost as a static organic nanobelt that is synthesized covalently.

We simulate a fluid droplet with suspended particles rising in another fluid with a diffuse interface model in which phase boundaries are replaced with smooth spreading interfaces. We find that at low Reynolds number the droplet terminal velocity decreases exponentially with particle concentration.

The field induced anisotropic interactions between like-charged colloidal particles is studied using direct numerical simulations, where the polarization of the electric double layer is explicitly computed under external AC electric fields. These interactions are found to depend on the magnitude E0 and frequency ω of the applied field, as well as the zeta potential, the Debye length, and the relative orientation of the particles. We also determined the range of E0 and ω over which a dipolar attraction is induced between a pair of like-charged colloids. Finally, we performed simulations for systems of six and twelve colloidal particles to study the stability of pear-chain-like configurations.

The dynamical behaviour of a charged colloid in an electrolyte solution is studied using direct numerical simulations via the smoothed profile method. We calculated the complex polarisability of a single colloidal particle under an AC electric field, where the polarisation is affected by the zeta potential of the colloid, the diffusion constant of the ions, the thickness of the electric double layer, and the frequency of the AC field. Two dynamically distinct regimes were observed depending on the applied frequency, specifically, on whether it is faster or slower than the ionic diffusion rate over the colloidal size. The present results showed very good agreements with the Maxwell–Wagner–O’Konski (MWO) theory and standard electrokinetic theories for all frequency regimes provided the zeta potential is low. For highly charged particles with high zeta potential, the standard electrokinetic models agree well with the present results for all frequency regimes. In the intermediate regimes, differences are obse...

Froth flotation is a separation process which plays a major role in the mining industry. It is essentially employed to recover a vast array of different valuable commodities such as rare earth minerals essential to the manufacture of high-tech products. Owing to its simplicity, the process is also widely used for the de-inking of recycled paper fibres and for the removal of pollutants from waste water. The flotation process essentially relies on the attachment of solid particles on the surface of gas bubbles immersed in water. The present study seeks to investigate the effect of the particle shape on the attachment mechanism. Using an in-house optical micro-bubble sensor the approach, the sliding and the adhesion of micron milled glass fibres on the surface of a stationary air bubble immersed in stagnant water is thoroughly investigated. The translational and rotational velocities were measured for fibres of various aspect ratios. The results are compared with a theoretical model and with experimental data obtained with spherical glass beads. It is found that the fibre orientation during the sliding motion largely depends on the collision area. Upon collision near the upstream pole of the gas bubble the major axis of the fibre aligns with the local bubble surface (tangential fibre alignment). If collision occurs at least 30° further downstream only head of the fibre is in contact with the gas–liquid interface (radial fibre alignment).

Contact inhibition is a cell property that limits the migration and proliferation of cells in crowded environments. Here we investigate the growth dynamics of a cell colony composed of migrating and proliferating cells on a substrate using a minimal model that incorporates the mechanisms of contact inhibition of locomotion and proliferation. We find two distinct regimes. At early times, when contact inhibition is weak, the colony grows exponentially in time, fully characterised by the proliferation rate. At long times, the colony boundary moves at a constant speed, determined only by the migration speed of a single cell and independent of the proliferation rate. Further, the model demonstrates how cell-cell alignment speeds up colony growth. Our model illuminates how simple local mechanical interactions give rise to contact inhibition, and from this, how cell colony growth is self-organised and controlled on a local level.

The collective dynamics of externally driven N_{p}-colloidal systems (1≤N_{p}≤4) in a confined viscous fluid have been investigated using three-dimensional direct numerical simulations with fully resolved hydrodynamics. The dynamical modes of collective particle motion are studied by changing the particle Reynolds number as determined by the strength of the external driving force and the confining wall distance. For a system with N_{p}=3, we found that at a critical Reynolds number a dynamical mode transition occurs from the doublet-singlet mode to the triplet mode, which has not been reported experimentally. The dynamical mode transition was analyzed in detail from the following two viewpoints: (1) spectrum analysis of the time evolution of a tagged particle velocity and (2) the relative acceleration of the doublet cluster with respect to the singlet particle. For a system with N_{p}=4, we found similar dynamical mode transitions from the doublet-singlet-singlet mode to the triplet-singlet mode and further to the quartet mode.

A consistent formulation is presented for the direct numerical simulation of an arbitrarily shaped colloidal particle at a deformable fluidic interface. The rigid colloidal particle is decomposed into a collection of solid spherical beads and the three-phase boundaries are replaced with smoothly spreading interfaces. The major merit of the present formulation lies in the ease with which the geometrical decomposition of the colloidal particle is implemented, yet allows the dynamic simulation of intricate three-dimensional colloidal shapes in a binary fluid. The dynamics of a rodlike, a platelike, and a ringlike particle are presently tested. It is found that platelike particles attach more rapidly to a fluidic interface and are subsequently harder to dislodge when subject to an external force. Using the Bond number, i.e., the ratio of the gravitational force to the reference capillary force, a spherical particle with equal affinity for the two fluids breaks away from a fluidic interface at the critical value Bo=0.75. This value is in line with our numerical experiments. It is here shown that a plate and a ring of equivalent masses detach at greater critical Bond numbers approximately equal to Bo=1.3. Results of this study will find applications in the stabilization of emulsions by colloids and in the recovery of colloidal particles by rising bubbles.

Thermo-hydrodynamic lubrication of a polymeric liquid composed of short chains between parallel plates is analysed by a multi-scale simulation, i.e. the synchronised molecular dynamics simulation v...

Direct numerical simulations are performed to investigate the microstructure of sedimenting particles, using a smoothed profile method. We used pair distribution function to find out particle prefe...

Previously, we have proposed to analyse the hydrodynamic interactions in a suspension of swimmers with respect to an effective hydrodynamic diffusion coefficient, which only considers the fluctuating motion caused by the stirring of the fluid. In this work, we study the diffusion of colloidal particles immersed in a bath of swimmers. To accurately resolve the many-body hydrodynamic interactions responsible for this diffusion, we use a direct numerical simulation scheme based on the smooth profile method. We consider a squirmer model for the self-propelled swimmers, as it accurately reproduces the flow field generated by real microorganisms, such as bacteria or spermatozoa. We show that the diffusion coefficients of the colloids are comparable with the effective diffusion coefficients of the swimmers, provided that the concentration of swimmers is high enough. At low concentrations, the difference in the way colloids and swimmers react to the flow leads to a reduction in the diffusion coefficient of the co...

We performed direct numerical simulations, using a smoothed profile method to investigate the inertial effects on the static and dynamic properties of a sedimenting suspension over a wide range of volume fractions from 0.01 to 0.4. We found that at Reynolds number Re ≤ 0.5, static and dynamic properties show the typical non-Brownian, Stokes regime characteristics, due to insignificant inertial effects. The microstructure analysis at the high Re revealed that at Re = 1 inertial forces have significant effects and these create a deficiency of particles around a given particle, which is more pronounced in the direction of gravity than in the perpendicular direction. This deficiency decreased the velocity fluctuations and particle diffusion in the vertical direction, whereas both of these properties remain unchanged in the perpendicular direction. Moreover, at Re = 10, strong inertial forces generated a significant deficit of particles in both directions, which decreased velocity fluctuations and particle diffusion in both directions. We also observed that the range of volume fraction affected by inertial forces is increased with the increase of Re. At high volume fraction ϕ ≳ 0.15, intrinsic many-body interactions dominate the phenomena and govern the transport properties thereafter.

We have proposed a new interpretation of fruit softening. This was accomplished by generating a hypothesis that probabilities of decay of fruit structure obey the Weibull probabilistic model that has been used in the field of reliability engineering. The elasticity of individual kiwifruit after harvest was continually and nondestructively measured until decomposition by using a laser Doppler vibrometer. The obtained decreasing pattern of elasticity of individual fruit was complex, diverse, and inhomogeneous. Nonetheless, it was satisfactorily explained by a tandem combination of 2 Weibull models involving 4 types of parameters: “shape” related to probability; “scale,” to velocity of decay; “location,” to time lag; and “mixing ratio,” to contribution of the 2 models. Averages of location, shape, and mixing ratio parameters obtained by the measurement of 33 fruit were significantly different between the 2 models, but the scale parameter was not. The results suggested that the complex softening patterns of individual kiwifruit could be described using the tandem model of Weibull distribution, and that the softening process of kiwifruit consisted of at least 2 independent decay phases that are characterized by 2 of 5 parameters: location and mixing ratio. Commencement of the first decay phase could be caused by ethylene treatment after harvest, and the second one spontaneously triggered after a certain time lag.

This paper focuses on non-spherical rod like particles and presents a computational technique for non-spherical particles in order to study the effect of shape on transport properties of particles. We used smoothed profile method with direct numerical simulations, in order to examine the microstructure and orientation of rigid rod like particles, in Stokes regime. These rod like particles are made up of spherical particles, so that smoothed profile method can be used without any extra effort. Microstructure shows the cluster formation and large inhomogeneties, even at lower volume fractions, and these inhomogeneties decrease with volume fraction. Orientation angle shows that particles prefer horizontal orientation at lower volume fraction and align themselves vertically, with increasing volume fraction.

Temperature dependences of the optical gap of diamond-like carbon (DLC) films were investigated by using a piezoelectric photothermal (PPT) spectroscopy, that detects the nonradiative transition of photoexcited electrons. Since the PPT signal intensity is expected to be proportional to its optical absorption coefficient, the optical gap was estimated by a Tauc plot. The temperature coefficient of the optical gap energy was found to be very small compared with that of other semiconductor such as Si. This result implies that the device performance is expected to be stable by temperature change and the DLC films are excellent as the next generation solar cells materials.

A direct numerical simulation study, using smooth profile method was performed to explore the effects of aspect ratio (ratio of vertical to horizontal length) of simulation box on spherical sedimen...

The effects of several surfactants on the homoepitaxial and heteroepitaxial growth of metallic films and multilayers have been studied and compared. Our measurements clearly revealed that pre-deposition of a small amount of surfactant prior to the adatom deposition changed thin film growth mode and structure. The pre-deposited surfactant enhanced layer-by-layer (LBL) growth of the homoepitaxial and heteroepitaxial growth of metallic films. The surfactant also enhanced the epitaxial growth of metallic multilayer.

We developed a simulation scheme to predict the dynamic behavior of colloidal dispersion called “smoothed profile (SP) method”. SP method provides a coupling scheme between continuum fluid dynamics and rigid-body dynamics through smoothed profile of colloidal particles. Moreover, SP method can incorporate multi-component fluids, such systems as charged colloids in electrolyte solutions. Numerical results which assess hydrodynamic interactions of colloidal dispersions are presented to validate SP method. Application of SP method is not restricted to a Newtonian solvent, but any constitutive model can be handled. Henceforth, it can be suitable to treat colloidal dispersions in complex fluids where solvent-mediated interaction dominate dynamical behaviors of colloids.

In this study, the effects of several underlayers (Cu, Co, Ag and Fe) on the thin structure of TiO2 by RF magnetron sputtering were studied and compared. The results of X-ray diffraction (XRD) revealed that the Cu and Ag underlayer worsened the crystal quality of the TiO2 films. When the Fe underlayer was used, fabricated TiO2 film showed a mixture of rutile and anatase. The Co underlayer, on the other hand, induced TiO2 anatase polycrystalline structure. This study also compared the surfactant effect of a Ag layer on the TiO2 film structure. The results of XRD, X-ray photoelectron spectroscopy, and atomic force microscopy revealed that the Ag layer works as an effective surfactant for reducing the surface roughness and the rutile growth of TiO2 film on the Fe underlayer.

This paper proposes a new method for evaluating the eco-efficiency of a household based on Factor X, which was proposed by Yamamoto and colleagues in 1999. We had proposed methods for evaluating Factor X of a household which consists of a building and home appliances, and implemented empirical evaluations. However, there remained the following two issues to be considered. One is how to quantify the function of a household. The other is how to take account of the so-called synergy effects. It proposes the method for calculating the overall functions of one household using the purchasing price as a weighting coefficient. This method is the same as Laspeyres quantity index in economics fields. As a synergy effect, the insulating effect in the building, etc. are considered. The result showed that the annual greenhouse gas emission of a typical household drastically decreased by 52.2% from 1990 to 2009 while the aggregated function of the household slightly decreased by 0.2% during the same period so that Factor X was 2.1 with respect to global warming. It was thus shown quantitatively that Factor X of households in Japan presumably improved during the period although only limited assessments were implemented.

The influence of a Bi surfactant layer on the structural and magnetic properties of Co/Cu multilayers grown onto Cu(1 1 0) buffer layer by RF magnetron sputtering has been studied. The results of X-ray diffraction revealed the initial deposition of a 2.0 A-thick Bi layer onto the Cu buffer layer prior to the deposition of the Co/Cu multilayer yielded high-quality fcc-(1 1 0) oriented epitaxial films. The X-ray photoelectron spectra revealed that Bi was segregated at around the top of the surface. Therefore, Bi was concluded to be an effective surfactant to enhance the epitaxial growth of Co/Cu(1 1 0) multilayer. The maximum giant magnetoresistance and antiferromagnetic interlayer coupling ratios of the Co/Cu multilayers were increased by using the Bi surfactant layer.

A new direct numerical simulation scheme, called "Smoothed Profile (SP) method," is presented. The SP method, as a direct numerical simulation of particulate flow, provides a way to couple continuum fluid dynamics with rigid-body dynamics through smoothed profile of colloidal particle. Our formulation includes extensions to colloids in multicomponent solvents such as charged colloids in electrolyte solutions. This method enables us to compute the time evolutions of colloidal particles, ions, and host fluids simultaneously by solving Newton, advection-diffusion, and Navier–Stokes equations so that the electro-hydrodynamic couplings can be fully taken into account. The electrophoretic mobilities of charged spherical particles are calculated in several situations. The comparisons with approximation theories show quantitative agreements for dilute dispersions without any empirical parameters.

Background and aims Complete submergence severely reduces growth rate and productivity of terrestrial plants, but much remains to be elucidated regarding the mechanisms involved. The aim of this study was to clarify the cellular basis of growth suppression by submergence in stems. Methods The effects of submergence on the viscoelastic extensibility of the cell wall and the cellular osmotic concentration were studied in azuki bean epicotyls. Modifications by submergence to chemical properties of the cell wall; levels of osmotic solutes and their translocation from the seed to epicotyls; and apoplastic pH and levels of ATP and ethanol were also examined. These cellular events underwater were compared in etiolated and in light-grown seedlings. Key results Under submergence, the osmotic concentration of the cell sap was substantially decreased via decreased concentrations of organic compounds including sugars and amino acids. In contrast, the viscoelastic extensibility of the cell wall was kept high. Submergence also decreased ATP and increased the pH of the apoplastic solution. Alcoholic fermentation was stimulated underwater, but the resulting accumulated ethanol was not directly involved in growth suppression. Light partially relieved the inhibitory effects of submergence on growth, osmoregulation and sugar translocation. Conclusions A decrease in the levels of osmotic solutes is a main cause of underwater growth suppression in azuki bean epicotyls. This may be brought about by suppression of solute uptake via breakdown of the H(+) gradient across the plasma membrane due to a decrease in ATP. The involvement of cell wall properties in underwater growth suppression remains to be fully elucidated.

Sustainable management of materials and products requires continuous evaluation of numerous complex social, ecological, and economic factors. A number of tools and methods are emerging to support this. One of the most rigorous is life-cycle assessment (LCA). But LCAs often lack a sustainability perspective and bring about difficult trade-offs between specificity and depth, on the one hand, and comprehension and applicability, on the other. This article applies a framework for strategic sustainable development (often referred to as The Natural Step (TNS) framework) based on backcasting from basic principles for sustainability. The aim is to foster a new general approach to the management of materials and products, here termed “strategic life-cycle management.” This includes informing the overall analysis with aspects that are relevant to a basic perspective on (1)sustainability, and (2) strategy to arrive at sustainability. The resulting overview is expected to help avoid costly assessments of flows and practices that are not critical from a sustainability and/or strategic perspective and to help identify strategic gaps in knowledge or potential problems that need further assessment. Early experience indicates that the approach can complement some existing tools and concepts by informing them from a sustainability perspective—for example, current product development and LCA tools.