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Biochar-amended soil (BAS) is increasingly considered an effective cover material for various geotechnical and geo-environmental applications, owing to its potential to minimize infiltration, support vegetation and sequester carbon dioxide. However, the detailed hydraulic characterization of unsaturated tropical soil amended with biochar remains largely underexplored. This study investigated the hydraulic properties of residual silty sand (SM) amended with varying biochar contents (3.5, 5, 10, and 20% by weight) derived from corncob feedstock. This research focuses on crucial unsaturated soil parameters, including soil-water retention curves (SWRCs), saturated permeability (ksat) and permeability (k) functions. The addition of biochar increased volumetric water content by 8–10% for suction ranges between 0 and 100 kPa compared to bare soil, due to the intraparticle voids and porosity of biochar. However, this effect was less pronounced with biochar percentages below 3.5%, especially for suctions below 5 kPa. The SWRCs of the BAS had bimodal shape with their fitting parameters nonlinearly increasing with biochar percentage. Biochar addition lead to notable reductions (about 20 times) in both saturated and unsaturated permeabilities, enhancement in suction stress and reduction in volume change upon drying. The implications of these observed behaviours were also discussed in terms of water holding capacity of biochar cover and environmental benefit in terms of CO2sequestration.

This Geotechnical Testing JournalSpecial Issue on Experimental Investigations from Very Small Strains to Beyond Failure presents selected papers originally submitted to the Eighth International Symposium on Deformation Characteristics of Geomaterials held in Porto, Portugal, from September 3–6, 2023 (IS-Porto 2023). This Symposium aimed at exploring and sharing ideas about the complex stress–strain response of geomaterials, including laboratory methods from very small to large strains; anisotropy and localization; time-dependent response of soils; characteristics of treated, unsaturated, and natural geomaterials; applications in field methods; evaluation of field performance in geotechnical structures; and physical and numerical modeling in geomechanics. The Symposium was a three-day event organized by the Faculty of Engineering of the University of Porto, under the auspices of the Technical Committee TC101 Laboratory Stress Strain Strength Testing of Geomaterials of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). This symposium was endorsed by the Portuguese Geotechnical Society (SPG), the Faculty of Engineering of the University of Porto (FEUP), under the activities of the Research Unit Institute of R&D in Structures and Construction (CONSTRUCT) of the Portuguese Foundation for Science and Technology (FCT). Building on the tradition of previous Symposia from Sapporo in 1994 to IS-Glasgow 2019, IS-Porto 2023 brought together more than 240 researchers and practitioners from 37 countries to share their experiences and explore new directions in testing, and in constitutive and numerical modelling of geomaterials. This Special Issue of ASTM International’s Geotechnical Testing Journalassembles eleven papers that illustrate some most recent, innovative, and significant advancements in laboratory equipment and experimental methodologies and procedures for the experimental investigations of soils from very small strains to beyond failure. Although most soil research laboratories are now equipped with the latest technology, in terms of transducers or testing apparatus, the inherent complex nature of soils makes studying them an ongoing challenge. This issue reflects the variety of topics that are still being considered, from difficult terrestrial soils, such as high plasticity stiff sedimentary clays (Sorensen et al. 2023), pumice soils (Hashimoto et al. 2023), gravelly (Nikoonejad and Mohsen Haeri 2023) and residual soils (Cheng and Leong 2023), and mine tailings (Narainsamy et al. 2023), to sampling and testing soils from Mars (Chaparro-López et al. 2023). Characterizing liquefiable soils, particularly partially saturated or gassy soils, and its post-liquefaction behavior continues to remain a subject of investigation, particularly in seismic regions, and is discussed in four papers, with emphasis on the applicability of partial saturation for liquefaction mitigation (Ahmad et al. 2023; Kaminski and Grabe 2023; Mele et al. 2023; Molina-Gómez et al. 2023). Greener methods of soil improvement are also explored, for example, biocementation under chemical damage (Ribeiro et al. 2023). The guest editors of this special issue would like to gratefully acknowledge the dedication and effort of all the authors and peer-reviewers of these papers, and the collaboration of the ASTM Editorial Team in the production of this special issue.

Use of the vertical drain method (hereinafter called “VD”) in peat ground is spreading to reduce residual settlement and increase strength by accelerating consolidation. In recent years, high embankments of nearly 10 m have been constructed on peat ground by using a combination of VDs, or plastic-board drains (PBDs) in particular, and various ground stabilization techniques. However, the conventional design methods include a number of unclear points. This paper focuses on the significant stress-dependency of coefficient of consolidation in peat, and describes a rational design approach to evaluating the long-term settlement and stability of foundation ground of VD-improved peat ground by modifying conventional design methods. The effect of VDs was evaluated from field observations on the settlement of test embankments constructed in Hokkaido, Japan, and simulations using the finite-element method were performed to interpret the behavior of the ground. A systematic series of parametric analyses demonstrated that, in peat ground with a high natural water content, the permeability decreases drastically as the load increases, and hence the residual settlement increases significantly and the stability is greatly reduced. Therefore, drain pitch needs to be considerably small under such conditions. Despite its common use in the conventional design of vertical drains, the accuracy of Barron’s solution is naturally limited in peat ground with high natural water contents since it assumes a constant value for the coefficient of consolidation.

This report describes the damage and ground movements observed in the residential area of Satozuka 1-Jo, Sapporo, Japan during the 2018 Eastern Iburi Earthquake as triggered by the liquefaction of pumice sand with which a valley had been filled. The geographical setting and the on-ground and aerial reconnaissance and soil characterization results are reported, leading to a possible scenario of the state of the pumice fill from its formation to the earthquake. This report focuses on the liquefaction disaster in Satozuka 1-Jo and summarizes it as follows: (a) The Satozuka residential area is located at the end of a plateau consisting of pyroclastic flow deposits, pumice sand called Spfl, deriving from the Lake Shikotsu caldera (30 to 40 thousand years ago), and some valleys that formed by erosion. (b) To develop level residential land, the pumice sand ridges were cut and the valleys were filled in with the pumice sand in the 1970s. The gradual loss of drainage capability might have led to a rise in the long-term groundwater level. (c) Liquefaction of the pumice sand fill was triggered and the fluidized fill flowed downwards along the sloped topography. Where the slope angle became steeper, asphalt pavements seem to have been pushed upwards and broken through by the liquefied soil, and the liquefied soil flowed out to the ground. (d) Physical and mechanical tests were conducted on the pumice sand fill, and its characteristics were reported with particular emphasis on its volumetric behaviour upon compaction, wetting, and pre- and post-liquefaction compression. Undrained cyclic triaxial tests showed the low liquefaction resistance of the pumice fill despite its high fines content (around 40%, non-plastic). (e) The laboratory test results and field evidence suggest that the potential key factor of the liquefaction at this site was the loosely compacted pumice sand fill, which easily forms a loose soil structure with macropores even when compacted on the wet side of optimum.

Roads on peat grounds are subject to stringent requirements in terms of controlling the residual settlement during their service period in order to minimize the post-construction maintenance work. This paper addresses the applicability of the Finite Element Method (FEM) by incorporating a time-dependent model for peats to an evaluation of the residual settlement. The applicability of isotach viscoplasticity, used to describe the peats’ behavior under variable-rate compression, was confirmed in laboratory tests. Long-term consolidation test results and a model simulation revealed the particular importance of two mechanisms in the residual settlement in peat grounds, namely, the stress-dependency of the coefficient of consolidation, cv, and the viscosity-induced secondary consolidation. A model peat ground, capturing these mechanisms, was implemented for the FEM and applied to a case history of a high-standard road construction in Hokkaido, Japan. The viscoplastic parameters determined from standard oedometer tests successfully reproduced the observed long-term settlement in a peat-dominated section of the expressway. The analysis was extended to address the settlement in the peat ground with the installation of prefabricated vertical drains (PVDs). The results indicate that the delayed primary consolidation due to the stress-induced cvreduction can be significantly alleviated, while the settlement arising from the secondary consolidation over a longer term is little affected by the PVDs. These insights point to the importance of untangling the two mechanisms of long-term settlement for the sake of making accurate predictions of the residual settlement in different time scales.

A soil investigation was conducted in peatlands in Japan, using two types of tube sampling methods, and the quality of the samples was evaluated. Unlike clays, peats easily lose water by compressive actions involved in sampler intrusion and core extrusion, leading to a significant loss of pore water. It was shown that this effect could be minimized by careful thin-wall sampling with a stationary piston, whereas open-drive sampling without a piston led to the significant compression of the sample core. The consequence of this disturbance on the in-situ behavior was interpreted through an examination of the mechanical properties of peat samples subjected to the “strain paths” expected during sampling in laboratory tests. By observing the deformation characteristics through a series of constant-rate-of-strain consolidation, unconfined compression, triaxial compression, and bender element tests, it was demonstrated that, contrary to soft clays, fibrous peats with high initial permeability potentially lead to the underestimation of the settlement during construction and the overestimation of strength due to inappropriate sampling. These results can be explained by the dominance of densification by disturbance over soil structure degradation. It was also noted that the sample quality varied considerably within the sampling tube.

There are many techniques for reducing the number of operations in directly solving a system of sparse linear equations. One such method is nested dissection (ND). In numerical analysis, the ND algorithm heuristically divides and conquers a system of linear equations, based on graph partitioning. In this article, we present a new algorithm for the first level of such graph partitioning, which splits a graph into two roughly equalised subgraphs. The algorithm runs in almost linear time. We evaluate and discuss the solving costs by applying the proposed algorithm to various matrices.

Towards the development of a mechanical model that can be part of multi-physical analysis of frozen soils, a program of systematic frozen-unfrozen parallel triaxial tests at different temperatures and strain rates was conducted. The mechanical behavior of the reconstituted high-plasticity clay samples was investigated and interpreted through a state concept based on Ladanyi and Morel’s (1990) postulate on the unique relationship between the inter-particle “effective” stress and the strain path. The Critical State Lines (CSLs) for clay specimens frozen undrained were mapped by referring to the shear behavior of unfrozen specimens sharing the same strain history. With other conditions set identical, the shear strength linearly increased with a decrease in the temperature for the range from −10°C to −2°C, and log-linearly increased with an increase in the strain rate for the range from 0.001%/min to 0.1%/min. Direct comparison of the strain-rate effects between frozen and unfrozen specimens with identical strain paths and states in the soil skeleton clearly indicates that the viscoplasticity derives from that of pore ice. A conceptual interpretative framework invoking temperature- and strain rate-dependent state bounding surfaces and CSLs was proposed to describe the behavior of frozen soils under steady and non-steady temperature and strain rate. The above observations of the behavioral features of frozen and unfrozen soils, with further experimental work, are expected to lead to the construction of a unified framework for describing the behavior under both states and the transition between them.

Donor‐independent platelet concentrates for transfusion can be produced in vitro from induced pluripotent stem cells (iPSCs). However, culture at 37°C induces ectodomain shedding on platelets of glycoprotein Ibα (GPIbα), the von Willebrand factor receptor critical for adhesive function and platelet lifetime in vivo, through temperature‐dependent activation of a disintegrin and metalloproteinase 17 (ADAM17). The shedding can be suppressed by using inhibitors of panmetalloproteinases and possibly of the upstream regulator p38 mitogen‐activated protein kinase (p38 MAPK), but residues of these inhibitors in the final platelet products may be accompanied by harmful risks that prevent clinical application. Here, we optimized the culture conditions for generating human iPSC‐derived GPIbα+platelets, focusing on culture temperature and additives, by comparing a new and safe selective ADAM17 inhibitor, KP‐457, with previous inhibitors. Because cultivation at 24°C (at which conventional platelet concentrates are stored) markedly diminished the yield of platelets with high expression of platelet receptors, 37°C was requisite for normal platelet production from iPSCs. KP‐457 blocked GPIbα shedding from iPSC platelets at a lower half‐maximal inhibitory concentration than panmetalloproteinase inhibitor GM‐6001, whereas p38 MAPK inhibitors did not. iPSC platelets generated in the presence of KP‐457 exhibited improved GPIbα‐dependent aggregation not inferior to human fresh platelets. A thrombus formation model using immunodeficient mice after platelet transfusion revealed that iPSC platelets generated with KP‐457 exerted better hemostatic function in vivo. Our findings suggest that KP‐457, unlike GM‐6001 or p38 MAPK inhibitors, effectively enhances the production of functional human iPSC‐derived platelets at 37°C, which is an important step toward their clinical application. StemCellsTranslationalMedicine2017;6:720–730

Tissue factor pathway inhibitor-2 (TFPI-2) is a major inhibitor of extracellular matrix degradation. Decreases in TFPI-2 contribute to malignant tumor cell production, and TFPI-2 is a presumed tumor suppressor. TFPI-2 gene transcription is regulated by two epigenetic mechanisms: DNA methylation of the promoter and K4 methylation of histone 3 (H3). Lysine-specific demethylase 1 (LSD1) and LSD2 demethylate H3K4me2/1. LSD1 has been implicated in TFPI-2 regulation through both epigenetic mechanisms, but the involvement of LSD2 remains unknown. We prepared a monoclonal anti-LSD2 antibody that clearly distinguishes LSD2 from LSD1. Knockdown of LSD1 or LSD2 by siRNAs increased TFPI-2 protein and mRNA. Simultaneous knockdown of both LSD1 and LSD2 showed additive effects. Bisulfite sequencing revealed that CpG sites in the TFPI-2 promoter region were unmethylated. These results indicate that LSD2 also contributes to TFPI-2 regulation through histone modification, and that further studies of the involvement of LSD2 in tumor malignancy are warranted.

Recent developments in laboratory techniques adopting highly precise local instrumentation have made possible the determination of all five independent elastic parameters necessary for describing the small-strain stiffness in cross-anisotropic soils. However, the techniques and the derivation procedures are not necessarily straightforward, and different processes sometimes lead to apparently inconsistent sets of parameters, revealing their complex and sensitive nature. This paper firstly reports a new fully-instrumented triaxial system that was optimised to test Japanese standard-sized (∅70–75mm) clay samples. The testing techniques and procedures to obtain the five cross-anisotropic elastic parameters, defined in this paper for recoverable strain smaller than 0.001%, are reviewed. Some updates, including notes on how to deal with creep in soft clays and the optimisation of drained probe rates, are described. A simplified procedure is proposed for completing the parameter determination, without actually measuring the radial displacement, by inverting the relationship between the undrained Young׳s modulus and the drained elastic parameters in saturated soils. The validity of this approach is demonstrated by comparing the parameters of sedimentary clays obtained with and without radial measurements. By eliminating the need for complex radial instrumentation, this approach will make the quantification of stiffness anisotropy more accessible in less-equipped laboratories.

Inflammation plays a crucial role in the pathophysiological characteristics of chronic kidney disease; however, the inflammatory mechanisms underlying the chronic kidney disease process remain unclear. Recent evidence indicates that sterile inflammation triggered by tissue injury is mediated through a multiprotein complex called the inflammasome. Therefore, we investigated the role of the inflammasome in the development of chronic kidney disease using a murine unilateral ureteral obstruction (UUO) model. Inflammasome-related molecules were up-regulated in the kidney after UUO. Apoptosis-associated speck-like protein containing a caspase recruitment domain deficiency significantly reduced inflammatory responses, such as inflammatory cell infiltration and cytokine expression, and improved subsequent renal injury and fibrosis. Furthermore, apoptosis-associated speck-like protein containing a caspase recruitment domain was specifically up-regulated in collecting duct (CD) epithelial cells of the UUO-treated kidney. In vitroexperiments showed that extracellular adenosine triphosphate (ATP) induced inflammasome activation in CD epithelial cells through P2X7-potassium efflux and reactive oxygen species–dependent pathways. These results demonstrate the molecular basis for the inflammatory response in the process of chronic kidney disease and suggest the CD inflammasome as a potential therapeutic target for preventing chronic kidney disease progression.

The donor-dependent supply of platelets is frequently insufficient to meet transfusion needs. To address this issue, we developed a clinically applicable strategy for the derivation of functional platelets from human pluripotent stem cells (PSCs). This approach involves the establishment of stable immortalized megakaryocyte progenitor cell lines (imMKCLs) from PSC-derived hematopoietic progenitors through the overexpression of BMI1 and BCL-XL to respectively suppress senescence and apoptosis and the constrained overexpression of c-MYC to promote proliferation. The resulting imMKCLs can be expanded in culture over extended periods (4–5 months), even after cryopreservation. Halting the overexpression of c-MYC, BMI1, and BCL-XL in growing imMKCLs led to the production of CD42b+platelets with functionality comparable to that of native platelets on the basis of a range of assays in vitro and in vivo. The combination of robust expansion capacity and efficient platelet production means that appropriately selected imMKCL clones represent a potentially inexhaustible source of hPSC-derived platelets for clinical application.

Chromophoric dissolved organic matter (CDOM) leached from leaf litter is a major source of humus in mineral soil of forest ecosystems. While their functions and refractoriness depend on the physicochemical structure, there is little information on the quality of CDOM, especially for that leached in the very early stages of litter decomposition when a large amount of dissolved organic matter (DOM) is leached. This study aimed to better understand the variations/changes in the composition of CDOM leached from senescent leaf litter from two tree species during the early stage of decomposition. Leaf litter from a conifer tree (Japanese cedar, Cryptomeria japonicaD. Don) and a deciduous broad‐leaved tree (Konara oak, Quercus serrataThunb.) were incubated in columns using simulated rainfall events periodically for a total of 300 d at 20°C. The quality of CDOM was investigated based on the fluorescence properties by using a combination of excitation–emission matrix fluorescence (EEM) and parallel factor analysis (PARAFAC). In addition, the phenolic composition of DOM was investigated at a molecular level by thermally assisted hydrolysis and methylation–gas chromatography–mass spectrometry (THM‐GC‐MS) in the presence of tetramethylammonium hydroxide (TMAH). The EEM was statistically decomposed into eight fluorescence components (two tannin/peptide‐like peaks, one protein‐like peak, and five humic‐like peaks). A significant contribution of tannin/peptide‐like peaks was observed at the beginning of incubation, but these peaks decreased quickly and humic‐like peaks increased within 1 mo of incubation. The composition of humic‐like peaks was different between tree species and changed over the incubation period. Since tannin‐derived phenolic compounds were detected in the DOM collected after 254 d of incubation on THM‐GC‐MS, it was suggested that tannins partially changed its structure, forming various humic‐like peaks during the early decomposition.

The mechanism by which thrombotic vessel occlusion occurs independently of plaque development or endothelial cell (EC) disruption remains unclear, largely because of an inability to visualize the formation of thrombus, especially at the single-platelet level in real time. Here we demonstrate that rapidly developing thrombi composed of discoid platelets can be induced in the mesenteric capillaries, arterioles, and large-sized arteries of living mice, enabling characterization of the kinetics of thrombosis initiation and the multicellular interrelationships during thrombus development. Platelet aggregation without EC disruption was triggered by reactive oxygen species (ROS) photochemically induced by moderate power laser irradiation. The inflammatory cytokines TNF-α and IL-1 could be key components of the EC response, acting through regulation of VWF mobilization to the cell surface. Thrombus formation was then initiated by the binding of platelet GPIbα to endothelial VWF in our model, and this effect was inhibited by the ROS scavenger N-acetylcysteine. Actin linker talin-dependent activation of alphaIIb-beta3 integrin or Rac1 in platelets was required for late-phase thrombus stability. Our novel imaging technology illustrates the molecular mechanism underlying inflammation-based thrombus formation by discoid platelets on undisrupted ECs and suggests control of ROS could be a useful therapeutic target for the prevention of thrombotic diseases.

The mechanism by which thrombotic vessel occlusion occurs independently of plaque development or endothelial cell (EC) disruption remains unclear, largely because of an inability to visualize the formation of thrombus, especially at the single-platelet level in real time. Here we demonstrate that rapidly developing thrombi composed of discoid platelets can be induced in the mesenteric capillaries, arterioles, and large-sized arteries of living mice, enabling characterization of the kinetics of thrombosis initiation and the multicellular interrelationships during thrombus development. Platelet aggregation without EC disruption was triggered by reactive oxygen species (ROS) photochemically induced by moderate power laser irradiation. The inflammatory cytokines TNF-α and IL-1 could be key components of the EC response, acting through regulation of VWF mobilization to the cell surface. Thrombus formation was then initiated by the binding of platelet GPIbα to endothelial VWF in our model, and this effect was inhibited by the ROS scavenger N-acetylcysteine. Actin linker talin-dependent activation of alphaIIb-beta3 integrin or Rac1 in platelets was required for late-phase thrombus stability. Our novel imaging technology illustrates the molecular mechanism underlying inflammation-based thrombus formation by discoid platelets on undisrupted ECs and suggests control of ROS could be a useful therapeutic target for the prevention of thrombotic diseases.

The dynamic and non-dynamic interactions between a gravity-type quay wall and a backfill ground were investigated by centrifuge model testing, considering cases in which a rigidly cement-stabilised ground existed at varying distances from the quay wall. In conducting the centrifuge tests, the performance of the instrumentation applied to measure the pressure from granular soils was critically assessed. At non-dynamic states, the backfill confined between the quay wall and the rigidly stabilised soil block exerted smaller earth pressure at deeper locations, at both apparently active and transient states. The calculation, based on perfect plasticity and considering friction arching, was useful in explaining these results. A similar feature was also observed during the steady-state oscillations, in the case of dry sand backfill, and was associated with the system’s increased seismic stability. In underwater cases, the pore water fluctuations in the backfill dominated the total earth pressure behaviour, with the active pressure being smaller again from a confined fill than from a fully extending one. Despite the reduced active pressure, placing the stabilised soil in the proximity of the quay wall increased the wall’s permanent seaward movement, unless the two bodies were in direct contact. This ostensible association of smaller active pressure with greater instability in the underwater cases cannot be explained by the conventional, simplified conception of the active earth pressure as a unilateral cause of instability. The evaluation of such unconventional backfill conditions seems to require rigorous consideration of the simultaneous soil–water-structure interactions.

In-situ static compaction by grouting is routinely used as a countermeasure against liquefaction in loose sandy ground. The surrounding ground's stress changes induced by grout injection are considered to be an important cause for the stabilisation effects, along with some densification of the ground in the bulb's vicinity. The present study investigates characteristics of the stress changes by simulating compaction grouting processes in a geotechnical centrifuge. Detailed descriptions are given of apparatus and experimental techniques specifically developed for conducting miniature injection tests. The observed increases in the horizontal stresses, evaluated in terms of the earth pressure coefficient, K, reflected the influence of grout pile spacing, and were found to be consistent with field measurements except near the surface. The centrifuge tests also allowed the changes in the dominant stress direction within the horizontal planes at the stabilised domain's centre to be evaluated, with the results indicating the dependency of the stress changes upon depth and interactions between neighboring grout piles. The significance of the stress changes in increasing the liquefaction resistance is demonstrated by mapping liquefaction curves against initial stress states through a series of cyclic hollow cylinder simple shear tests.

The report gives a brief overview of the history and development of Soils and Foundations from its founding in 1960 to the golden jubilee year 2010. The statistics concerning the journal's distribution and the academic contents of the published papers are presented, updated from those first published by Takemura et al. (1999). Major events are chronicled and their impacts the assessed on the readers, contributors and the course of the journal's later development. Such events include online publishing and adopting the impact factor, among others. The long-term trends in the research topics, employed approaches (experimental, analytical, etc.), authors' identity, etc. are discussed based on the statistics considering all the papers published in the past. The report also offers a complementary perspective to the journal's contributions to the geotechnical society by reviewing the award-winning papers.

To clarify the fragmentation mechanism of a molten metallic fuel jet in a sodium pool under highejection-velocityconditions that correspond to the medium- and high-burnup conditions in the metallic fuel core of liquid-metal-cooled fast breeder reactors, a series of experiments with molten copper as a metallic fuel simulant and a sodium pool was carried out. Under low-ejection-velocity conditions in the range of an ambient Weber number (Wea) < 200, the fragmentation of the molten copper jet depends on the initial superheating of the jet. The size of copper fragments decreases with increasing initial superheating. Under high-ejection-velocity conditions in the range of Wea≥ 200, the size of the fragments is confirmed to be almost independent of the initial superheating of the jet. Furthermore, the size of the fragments agrees well with that evaluated using the Rayleigh-Taylor instability model, in which the fragment size is assumed to be equal to half the fastest growing wavelength. This result is qualitatively consistent with the characteristics that the molten jet column with large inertia force owing to the high ejection velocity, which transports enthalpy downwards, can penetrate the decelerated leading edge and can directly come into contact with sodium successively.

The progression of hypothetical core disruptive accidents in metallic fuel fast breeder reactors is strongly affected by the fragmentation of molten metallic fuels due to the molten fuel-coolant interaction (FCI). As a basic study of FCI, the present paper focuses on the fragmentation of a single molten copper droplet with mass from 1 to 5 g, whichpenetrated a sodium pool at instantaneous contact interface temperatures (Ti) from 995 to 1,342°C. Intensive fragmentation of a single molten copper droplet was clearly observed even if Tivalues are below the melTsing point (1,083°C) of copper besides the higher Tirange. The intensive fragmentation shows that the mass median diameters (Dm) of copper droplets with a fivefold difference in mass or the same mass have little difference, i.e., they are nearly the same. Under the lower Ticondition, the Dmdata of droplet fragments of both the same and different masses scatter widely. It is found that the present Dm/D0data of mass median diameter normalized by the diameter before touching sodium (D0) give a distribution with larger values than those of molten copper jets with large mass from 20 to 300 g under the lower Ticondition, which were previously reported by the authors, because of the limited amount of heat of droplets. The present Dm=D0 data under the higher Ticondition are found to show an effecTive fragmentation compared with those of molten copper jets with a large mass of 4 kg.

This protocol describes a method for attaching single isolated cardiac myocytes to carbon fibers for mechanical manipulation and measurement. This method relies on cell-adhesive carbon fibers that attach easily to the cell membrane without causing damage, and is thus applicable to intact myocytes. To connect the carbon fiber to micromanipulators, a fiber holder with glass capillaries must first be fabricated. After connection of the fibers to the micromanipulators, firm attachment is easily established by gently pressing the fiber tip onto the cell membrane. Unlike other methods, this technique does not require vast technical expertise, and therefore greatly facilitates experiments. This method enables detection of the effect of drugs, genetic defects or the expression of exogenous proteins on both active and passive properties of cardiac myocytes. In combination with other experimental procedures, this technique can also be applied to the study of mechano-transduction. This protocol can be completed in 3.5 h.

Abstract: Green fluorescent protein (GFP) is widely used as a biologically inert expression marker for studying the effects of transgene expression in heart tissue, but its influence on the contractile function of cardiomyocytes has not yet been fully evaluated. We measured the contractile function of isolated rat ventricular myocytes before and after infection with a recombinant adenovirus expressing GFP (Adv-GFP). Myocytes infected with a non-transgene-containing adenovirus (Adv-Null) or uninfected myocytes (UI) served as controls. Using a carbon-fiber-based force-length measurement system for single cardiomyocytes, we evaluated the contractile function over a wide range of loading conditions including the shortening fraction (%FS) and maximal shortening velocity (Vmax) under the unloaded condition, and isometric force. At 24 hours after infection, nearly 80% of the Adv-GFP-infected myocytes expressed GFP. We found that the %FS and Vmax did not differ among the three groups, however, the isometric force showed a mild, but significant, decrease only in Adv-GFP myocytes (Adv-GFP: 29.1 ± 4.0 mN/mm2; Adv-Null: 42.8 ± 6.2 mN/mm2; UI: 47.1 ± 4.8 mN/mm2; p = 0.03). An evaluation of the contractile function of isolated cardiomyocytes under high load conditions revealed impaired isometric contractility by GFP expression. Adv-GFP expression may not be an ideal control for specific gene expression experiments in myocardial tissue.

To clarify the effects of the principal factors that govern the thermal fragmentation of a molten metallic fuel jet in the course of fuel-coolant interaction, which is important in evaluating the sequence of core disruptive accidents (CDAs) for metallic fuel fast reactors, basic experiments were carried out using molten metallic fuel simulants (copper and silver) and a sodium pool.Fragmentation of a molten metal jet with a solid crust was caused by internal pressure produced by the boiling of sodium, which is locally entrapped inside the jet due to hydrodynamic motion between the jet and the coolant. The superheating and the latent heat of fusion of the jet are the principal factors governing this type of thermal fragmentation. On the other hand, the effect of the initial sodium temperature is regarded as negligible in the case of thermal conditions expected to result in CDAs for practical metallic fuel cores. Based on the fragmentation data for several kinds of jets (Cu, Ag, SUS, U, and U-5 wt% Zr alloy), an empirical correlation is proposed that is applicable to the calculation of a mass median diameter of fragments produced by the thermal fragmentation of the jet with a solid crust under low ambient Weber number conditions.

A new three-dimensional stress-strain model of sand is proposed by using the concept of multiple shear mechanisms which previously has been developed in a two-dimensional manner. The original model exhibited excellent capability for simulating the principal stress axis rotation. By extending this approach with a new dilatancy model, the present model makes it possible to describe a general stress state in three-dimensional space with the whole six degrees-of-freedom of stress taken into account. Modelling of sand behaviours under general drained and undrained conditions was achieved by applying a stress-dilatancy relation to all individual shear mechanisms. It was demonstrated that the model predicts well soil behaviour in rather complex three-dimensional shear loadings as well as in more fundamental two-dimensional ones.

Musashi has been identified as an RNA-binding protein thought to be involved in asymmetric divisions during Drosophilaneural development. To analyze expression patterns of mammalian Musashi homolog Musashi-1 in human normal colon crypt, 155 colon crypts separated from biopsy specimens of normal colonic mucosa were evaluated. Specimens were fixed, microdissected to isolate a few crypts, immunostained with anti-Musashi-1 antibody (14H1), and examined under confocal laser scan microscopy. The number of Musashi-1-positive cells in each crypt was 19.0 ± 7.53 (mean ± SD). Most Musashi-1 positive cells were located at the crypt base, between cell positions 1 and 10. Distribution of Musashi-1-positive cells corresponded with that of stem cells, as outlined in previous reports, implying that Musashi-1 is a key control element of asymmetrical division within the colon crypt. This is the first report outlining expression of Musashi-1 in human colon crypt cells.

The organoclay quasicrystals formed by exchange reactions of fluoromagnesian smectite (FMS) and two kinds of cationic surfactants were investigated by X-ray diffraction (XRD) of both aqueous suspensions and dried powders. ζ potential measurements were also carried out. The two cationic surfactants employed in this study, dodecyltriphenylphosphonium bromide (C12PBr) and dodecyltrimethylammonium bromide (C12NBr), have the same alkyl chain length but different head group structures. In aqueous suspensions of C12N/FMS, regular stacking with a basal spacing of 2.28 nm was observed within the range 0.4 to 1.0 of the cation exchange capacity (CEC) of the C12N/FMS ratios. The basal spacing was constant in this range. The most intense diffraction for the C12N/FMS suspension was observed at 0.6 CEC, and a further increase in the C12N/FMS ratio resulted in a decline of the diffraction intensity and a slight increase in the peak width. On the other hand, in C12P/FMS suspensions with the surfactant/FMS ratios <0.6 CEC, only weak, broad XRD peaks were observed. With higher C12P/FMS ratios (0.8 and 1.0 CEC), strong diffraction peaks appeared with a basal spacing of 3.20 nm. The difference in the observed basal spacings of C12N/FMS and C12P/FMS tactoids was ∼0.9 nm, which did not agree with the difference in the estimated height of the two surfactants (∼0.1 nm). These differences of the tactoid structures between C12N/FMS and C12P/FMS suspensions could be explained in terms of the difference in the adsorption manner of the surfactants on the silicate surface and in the size of the surfactant head groups.

trans-1,2-Cyclohexanediol, the major metabolite of the cilexetil moiety of candesartan cilexetil (CC), has been reported to have potent pro-arrhythmic effects in dogs with congestive heart failure (CHF), especially when co-administered with digoxin. To verify this and to clarify the clinical relevance and the underlying mechanisms, a series of in vivo and in vitro experiments was conducted. When CC up to 300 mg/kg was administered orally to intact dogs, no changes in the electrocardiograms (ECG) or the required cumulative doses of ouabain to induce ventricular arrhythmias were observed. In dogs with CHF, intravenous bolus administration of trans-1,2-cyclohexanediol at 4 mg/kg followed by continuous infusion at 0.1 mg·kg-1·min-1 had no effects on the ECG parameters, the type, incidence, and onset time of digoxin-induced arrhythmias or the metabolism of digoxin. In an in vitro experiment using isolated guinea pig papillary muscle, trans-1,2-cyclohexanediol (1 – 100 μmol/L) showed no effects on any parameter of the action potentials. Because no effects were observed in these experiments where the exposure levels of trans-1,2-cyclohexanediol were extremely high compared to those in humans given the maximum therapeutic dose of CC, it is unlikely that CC would induce arrhythmias in clinical use even in patients treated with cardiac glycosides.

The rate dependent nature of liquefied sand was investigated by laboratory shear tests. Since previous experience has revealed the many difficulties inherent in maintaining the state of liquefaction of a sandy specimen, new measures were attempted. The test results indicate that the measured shear stress consists of frictional and rate dependent components, and a viscosity coefficient was assessed from the latter component. The measured viscosity varies with the rate of strain as well as the magnitude of strain itself. A similar test on a dry specimen revealed less viscosity and implied that a major part of rate dependency comes from the behavior of pore liquid in the case of water-saturated sand. It was interesting, moreover, that sand with fines was of less viscosity. Finally, a numerical analysis was conducted on a real liquefaction-induced ground deformation and the results were consistent with the observation.

In order to verify the thermal fragmentation of a molten jet dropped into a sodium pool at instantaneous contact interface temperatures below its freezing point, a basic experiment was carried out using molten copper and sodium. Twenty grams of copper was melted in a crucible with an electrical heater and was dropped through a 6 mm nozzle into a sodium pool of 553 K, in the form of a jet column. Thermal fragmentation originating inside the molten copper jet with a solid crust was clearly observed in all runs. It is verified that a small quantity of sodium, which is locally entrapped inside the molten jet due to the organized motion between the molten jet and sodium, is vaporized by the sensible heat and the latent heat of molten copper, and the high internal pressure causes the molten jet with a solid crust to fragment. It is also found that the fragmentation caused in the molten copper-sodium interaction was severer than that in the molten uranium alloy jet-sodium interaction, which was reported by Gabor et al, under the same superheating condition and lower ambient Weber number condition of molten copper.

The characteristics of a surface plasmon resonance (SPR) sensor prepared by coating a metal film evaporated on a prism with a polymer film containing tetra-n-butyl thiuram disulfide (TBTDS) were studied. The differences in the sensitivity, selectivity, and detection limit for a Zn2+ion of the SPR sensor were reported as a function of the thickness of the polymer film, the kind of a metal film, and the kind of a polymer film. The thinner was the polymer film, the higher was the sensitivity, and the lower was the detection limit. The Ag film gave to the SPR sensor higher sensitivity than the Au film. TBTDS contained in the poly(vinyl chloride) (PVC) film slightly improved the selectivity toward the Zn2+ion. A non-conditioned poly(methyl methacrylate) (PMMA) film containing TBTDS gave a lower detection limit of 1.0 × 10-6mol/l, which is similar to that obtained by using an ion selective electrode (ISE) method, than the PVC film. The PVC film, however, gave higher concentration resolution than the PMMA film.

A surface plasmon resonance (SPR) sensor was applied to analyses of some amine compounds (n-butylamine, isobutylamine, aniline, and N,N-dimethylaniline) by using a polymer film and an acid-base reaction in it. Poly(acrylamide) (PAA) was adopted as the polymer film and was immobilized on an Au film to prepare a sensor chip. Pivalic acid was entered into the PAA film as an acid. The PAA film with a thickness of 50 nm gave the highest sensitivity to the SPR sensor. Although water was better concerning the sensitivity for the SPR sensor as the solvent, ethanol was adopted because it dissolves well all of the amine compounds used. The Au film coated with the PAA film gave higher sensitivity for analyses of n-butylamine and isobutylamine, and lower sensitivity for analyses of aniline and N,N-dimethylaniline than an Au film without the PAA film. The PAA film containing pivalic acid gave 4 - 5 orders of magnitude higher sensitivity to the SPR sensor for analyses of all the amine compounds due to the reaction between pivalic acid and these amine compounds.

Quasicrystals of synthetic fluoromagnesian smectite (FMS) in dodecyltrimethylammonium chloride (DTAC) solutions were investigated as a function of the DTAC concentration by wet type X-ray diffraction (XRD) ? potential measurements, and dispersion and coagulation (DC) tests. The FMS had an electronegative potential and it was dispersed randomly in an aqueous suspension without DTAC. When the DTAC concentration was 0.002 mol/dm3, FMS tactoids started to develop a structure in which the layer thickness was 1.85 nm. At the isoelectric point, the DTAC concentration was 0.012 mol/dm3and the FMS tactoid formed a regular stacked structure with a 2.25 nm layer thickness. As the ? potential of FMS changed from negative to positive, the DC test and XRD measurement showed that the FMS association gradually changed from coagulation to dispersion, which indicates that the formation of the bilayer of surfactants on the surface of FMS produces a repulsion between DTA+adsorbed on the silicate layer of the FMS surfaces. When the equilibrium concentration of DTAC in solution exceeded the critical micelle concentration (CMC), the ? potential of FMS became greater than the previous values. The XRD analysis of this suspension showed that there were two kinds of rational FMS stackings; one has a layer thickness of 3.20 nm, and the other has a layer thickness of 5.45 nm due to an interstratified structure composed of 3.20 and 2.25 nm layers. The interstratified structure was confirmed by the calculated XRD profiles.

A fluorine expandable mica (EM), having two-dimensional spread in its crystal form, was used as a template for carbonization of organic liquids such as quinoline and pyridine. Despite Intrinsic volatile under the ambient pressure, these organic liquids inserted into the interlayer space of mica yielded carbonaceous compound after heat treatment over 500°C in inert atmosphere. The particle size of the compound separated from the mica layer depends on that of mica as a template. Detailed TEM observation revealed unique structure, namely each particle comprised two structural parts: film and surrounding rim part. The film part was very thin, thus being transparent for SEM observation and rim part has constant width of about 20 nm. This structure is particularly interesting, because it can be carbon thin film supported by carbon micro-ring.

The adsorption of dodecyltrimethylammonium bromide (DTAB) onto natural muscovite mica and a synthetic expandable mica (EM) in aqueous solution has been investigated using both microscopic and macroscopic surface characterization techniques. The electrokinetic properties of the surfaces were monitored as a function of the concentration of DTAB using atomic force microscopy and microelectrophoresis. The adsorption isotherm of DTAB on EM was measured up to a solution concentration just below the critical micelle concentration of the surfactant. The thickness of the adsorbed layer on EM was determined using X-ray diffraction. Results indicate that the adsorbed layer consists of molecules lying quite flat on the mica surface at low concentrations and adsorbed in interleaved aggregate structures at concentrations approaching the critical micelle concentration of the surfactant in solution.

Static and dynamic load balancing strategies for a multiprocessor system for a ray tracing algorithm based on constant subdivision are presented. An object space is divided into regular cubes (subspaces), whose boundary planes are perpendicular to the coordinate axes, and these are allocated to the processors in the system. Here, load balancing among the processors is the most important problem. Firstly, in a category of static load balancing, strategies for mapping the subspaces into the processors are evaluated by simulation. Moreover, we propose a hierarchical multiprocessor system in order to realize dynamic load balancing with the static one. Its architecture can overcome the limitation of the static load balancing in a large scale multiprocessor system.

A unique interstratified expandable mica was obtained by cation exchange treatments using an expandable mica synthesized from talc. The 23Na magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectrum of the expandable mica used as a starting material showed that it had 2 kinds of Na+: one was exchangeable and the other was not exchangeable. Half of the Na+per unit cell of the expandable mica was replaced with Mg2+by cation exchange treatments. The X-ray powder diffraction (XRD) analysis of the Mg2+-exchanged expandable mica, after heating at 73°C, indicated that Na+in the interlayer sheets was exchanged with Mg2+in every second layer and that it had an interstratified structure with a 12.5-Å layer thickness and a 9.6-Å layer thickness. The structure of the Mg2+-exchanged expandable mica was changed into a unique interstratified structure by the calcination at 600°C; one component had a stacking sequence of talc and a small amount of OH−, but the other had a different stacking sequence from talc and no structural OH—.

Expandable fluorine micas were synthesized using talc and Na2SiF6at 800°C for 2 hours in air, nitrogen, argon, and under vacuum. Gaseous SiF4, generated from Na2SiF6, and the resultant amorphous sodium silicofluoride formed during the reaction between talc and Na2SiF6below 900°C are taking active part in the formation of expandable micas because the intensity of the 12.5 Å reflection of expandable micas decreases as the gas flow increases in the furnace. Expandable micas seem to be formed by the transformation from talc taking place without the entire disruption of the original atomic arrangement. This takes place with the loss of one Mg2+from an octahedral site and by the intercalation of every two Na+into the interlayer site of talc. Infrared absorption and thermal analyses show that expandable micas include a small amount of OH−in their structures.

The adsorption of dodecylammonium chloride (DAC) to the basal plane of muscovite mica was investigated together with that of fused silica by means of zeta potential, adsorption isotherms, and contact angle measurements at pH 3 where the zeta potential for the mica (-75 mV) was more negative than that for the silica (-25 mV). Marked changes in zeta potential, adsorption, and contact angle occurred at critical concentrations of 10-5and 2 × 10-4MDAC for mica and silica, respectively, implying that the difference in the inner Helmholtz potential between mica and silica is -85 mV. The negative surface charges for mica and silica were neutralized at the adsorption densities of 8.4 × 10-11and 8.6 × 10-12mol/cm2, respectively. The interaction between hydrocarbon chains in adsorption energy gave the values of -0.87 and -0.53 kT per CH2group for the mica and the silica, respectively. The contact angles for mica gave the maximum value of 55°, which was higher than the value of 25° for silica at charge-neutralized surfaces. At a concentration of 10-2MDAC, the zeta potential for mica showed the value of 100 mV which was higher than the one of 20 mV for silica, and the ionized fraction of DA+ions in the second layer gave the values of 0.08 to 0.18 for both the mica and the silica. These values agreed well with that of 0.14 for micelles. These observations supported the difference in zeta potential between mica and silica at pH 3.

A new model is proposed for describing freeze-thaw-induced plastic volume changes in saturated clays based on microscopic inhomogeneities inherent in the soil structure and the pore water transfer between them. It is shown through a simple inhomogeneous mesostructure model that the equilibrium state reached after freezing serves as an important reference state for interpreting the volumetric behaviour. The soil state evolution towards this freeze equilibrium state clarifies many features seen in the experimentally observed freeze-thaw behaviour, such as the existence of a limiting stress level above which no plastic volume change occurs. The process of freezing/thawing is modelled as a rate process approaching the freeze equilibrium line (FEL) and representing the eventual equilibrium states at a particular sub-freezing temperature, exploiting a newly defined state parameter, ψfe. The model offers a mesoscopic three-dimensional yield surface in the specific volume – effective stress – temperature space, expressed by a simple equation. Although the model’s essence is encapsulated in only two simple equations, it can simulate well the experimentally observed volume change accumulation with freeze-thaw cycles under different stress levels and densities (or over-consolidation ratios). As the model is formulated in an incremental rate form, it can be applied to general freeze-thaw problems, even those with irregular temperature and stress history – a feature not seen in existing models.

The reactions of norbornadiene in amine by the use of nickel, palladium and rhodium complexes have been studied in the presence of protic acid. A catalytic system of Ni(COD)2(1)-n-Bu3P gives a mixture of 5-exo-(o-tolyl)-2-norbornene (3) and 5-exo-(N-amino)-2-norbornene (4). Bis(triphenylphosphine)(maleic anhydride)palladium (5) gives 3-(N-amino)nortricyclene (6). Dichlorotetrakis(cyclooctene)dirhodium (10) gives a [2+4] cycloaddition product (11). All these reactions mechanisms are discussed from the point of view of an acid-promoted reaction on low-valent transition metal complexes.