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A detonation is a combustion wave that propagates at supersonic speed (2∼3 km/s) in a combustible mixture. There are many fundamental studies of detonation waves and detonation engine systems. The detonation cycle has a higher thermal efficiency than a conventional constant-pressure combustion cycle. Therefore, it is expected that a high-efficiency propulsion system can be realized using detonation waves.A rotating detonation engine (RDE) uses continuous detonation propagating at a bottom in an annular combustor. As detonation waves propagate at a supersonic speed only in the bottom region of the RDEs, the combustor can be shortened. However, the combustor needs cooling system due to high heat flux to the combustor wall. In this experimental study, we performed combustion tests of RDE system using gaseous ethylene and oxygen as the propellant. This RDE system performance will also be demonstrated in space environment by the sounding rocket. We measured the combustor pressure, temperatures, heat flus, mass flow rate and thrust. The RDE system used in this study is shown in Figure 1. We performed the long-duration rotating detonation engine combustion tests for at sea level condition. The stable trust histories were obtained.

Hikikomori has been recognized as a significant social issue in Japan. It is a Japanese term that refers to young people (aged 18-39 years) who have been in an asocial state of social withdrawal and social isolation for over six months. The Cabinet Office of Japan suggests that the number of hikikomori youth has reached approximately 700,000 and is still growing. In addition, recent surveys suggest that hikikomori has a prolonged influence, such that more than 610,000 middle-aged people (aged 40-65 years) have remained in a hikikomori state which began at a younger age. The major challenge of this issue facing experts is that Hikikomori individuals usually repulse external support or interventions, either consciously or unconsciously. Hence, psychological therapies reliant on external interventions have inevitable limitations in curing hikikomori. Our methodology of C-BED (Community-Based Enterprise Development), on the other hand, has proven effective in overcoming this challenge, based on the results of our pilot study supported by Japanese NGO and TOYOTA Foundation. C-BED is a peer-to-peer learning process in which hikikomori share their thoughts with peers in similar situations through online dialogues. In developing the original program, we adopted the Dialectic Behavior Therapy (DBT) to the C-BED and produced 10 online modules for participants to interact by using online SNS group chat. The results of the online workshops (online C-BED) for five Hikikomori youth suggested that their psychological anxiety has been decreased and their willingness to participate socially has been strengthened after attending a 3-course module. In addition, C-BED has incomparable advantages in approaching hikikomori in remote areas at a meager cost, and in bringing positive changes to those who are struggling with psychological problems, no matter their cultural or economic backgrounds. &nbsp

Simultaneously achieving homogeneous dispersion and appropriate interfacial adhesion is the foremost concern for designing high-performance carbon nanotube (CNT)/Al matrix composites. Herein, a strategy for surface modification was developed to fabricate uniform CNT/Al composites with enhanced interfacial strength. Small quantities of Al2O3 nanoparticles were locally adhered to the surface of functionalized CNTs by electrostatic self-assembly, thereby promoting the adsorption of high concentrations of CNTs onto Al powders and hindering the agglomeration of CNTs. After densification, the CNTs retained their structural integrity and exhibited both individual distribution and unidirectional alignment in the matrix. As revealed by high-resolution transmission electron microscopy, the Al2O3 nanoparticles promoted a large elastic buckling of the nanotube inner wall and formed a curved, stable contact with the CNTs, producing strong anchors at the CNT-Al interface. Consequently, the CNT-Al2O3/Al composites exhibited enhanced mechanical properties compared with the CNT/Al composites, while maintaining superior electrical conductivity. This work demonstrates the great potential of surface decoration in producing advanced CNT/metal composites in electrical applications.

Aluminium 6061 alloy matrix composite materials reinforced with carbon nanotubes (CNTs) and silicon carbide nanoparticles (nSiCs) were prepared by high-energy ball milling and hot pressing. In addition to inducing fine particle strengthening, nSiCs were also used as a solid mixing agent to improve the dispersion of the CNTs in the Al matrix powder. The dependence of the densification and mechanical strength of the composites reinforced with the dual nanoparticles on the milling time is discussed. The crystallite sizes of Al in the composites were also investigated. Moreover, the relative defect ratios of the CNTs in the composites were calculated from the intensities of the D and G peaks of the Raman spectra. With this new approach to composite fabrication, a hardness and tensile strength of 334 HV and 293 MPa, respectively, were achieved. The high-energy ball milling time significantly affected the microstructure and mechanical properties of the composites; however, the dual nanoparticle reinforcement can potentially be used in a variety of industrial component materials with precisely controlled material properties.

In this study, we evaluated the thermal stability and fragility of Fe 76 Si 9 B 10 P 5 supercooled liquid by using micrometer-scale particles prepared via a container-less solidification process. After construction of time-temperature-transformation (TTT) diagram of crystallization by means of isothermal DSC under various temperatures, we could successfully measure the viscosity of the particles in the supercooled liquid region by employing the single particle compressive test (SPCT). It is revealed that the temperature dependency of viscosity cannot be well fitted by the Vogel–Fulcher–Tammann (VFT) formula but can be fitted by an Arrhenius plot. The Angell plot indicates that the apparent fragility is higher than that of SiO 2 and the fabricated particles have hetero-amorphous structures composed of high-density nanoscale clusters dispersed uniformly in a glassy matrix phase.

Quantitative characterization of interfacial shear strength (IFSS), in multi-walled carbon nanotube (MWCNT)-reinforced Al matrix composites, has been carried out using an in-situ pull-out technique. The end of an MWCNT protruding out of the tensile fracture surface of the composite was bonded to the tip of an atomic force microscopy (AFM) cantilever using an electron-beam-induced deposition method. The MWCNT was pulled out from the Al matrix using a nanomanipulator system installed inside a scanning electron microscope (SEM). The effective embedded length of the MWCNT incorporated in the Al matrix was evaluated by observing the pulled out MWCNT under high-resolution transmission electron microscopy (HRTEM). Valid results were obtained for six MWCNTs with straight, visibly damage-free embedded parts nearly perpendicular to the fracture surface. The IFSS between the MWCNT and the Al matrix was 24.8 ± 3.2 MPa. The ultimate tensile strength (UTS) of the MWCNT/Al composites is in good agreement with that estimated by the shear lag model using these IFSS values, resulting in the realization of 60% load transfer efficiency at the directly contacted MWCNT-Al interface in the MWCNT/Al composites. No MWCNT failure was observed during the pullout in this study.

The Codex Alimentarius Commission has recently adopted maximum levels for inorganic arsenic (As; in 2014) and total cadmium (Cd; in 2006) in polished rice grains to maintain food safety and to decrease the risk to human health. As rice is a staple crop in Japan and monsoon Asian countries, reducing concentrations of As and Cd in rice is an urgent matter. In flooded conditions, Cd concentration in soil solution decreases whereas As concentration increases. Therefore, we aimed to evaluate the efficiency of iron-bearing materials to decrease As concentration in soil solution and rice (Oryza sativa L.) grain under submerged cultivation, while also considering Cd concentration. In experiments conducted in paddy fields in six regions, As concentrations in the soil solution during the cultivation period decreased in the following order: control (REF) > steel converter furnace slag (SCS) > non-crystalline iron hydroxide (FH) > zero-valent iron (ZVI). The concentrations of As in brown rice were in the same...

The interface and interfacial reactions in Al-matrix composites reinforced with multi-walled carbon nanotubes (MWCNTs) were thoroughly investigated by high-resolution transmission electron microscopy combined with a precisely controlled heat treatment in the solid state. It was shown that MWCNT (002) formed a coherent interface with the low-index Al planes of Al (111), Al (220), and Al (002), realizing a stable interface. Aluminum carbides (Al4C3) were preferentially formed at the active prism plane edges sited at the open ends and acid treatment-induced surface nanodefects of MWCNTs. The Al4C3 maintained the shape of the pristine MWCNT and showed a typical orientation relationship with the Al matrix, that is, Al (111)//Al4C3 (001). It was suggested that the diffusion of Al atoms through Al4C3 dominated the growth of Al4C3; the Al4C3 originated at the open MWCNT tips may quickly grow in the direction of the MWCNT, while the nanodefect-originated Al4C3 may grow simultaneously in the and directions of the MWCNT. The activation energy of Al4C3 formation, the appearance of twinning in single-crystal Al4C3, and the possible influence of the Al4C3 formation on the enhancement of load transfer at the MWCNT/Al interface were also studied.

Increased strength of Al matrix composites (AMCs) with a high electrical conductivity are in demand to replace copper conductors. In this study, a high-performance Al4C3/Al composite was synthesized in situ via the high-energy densification of uniform graphene oxide (GO)/Al powder combination; GO was completely transformed to monocrystalline Al4C3 nanorod structures, robustly bridging across the Al grain boundary. The formation mechanism of interfacial Al4C3 was illustrated by high-resolution transmission electron microscope observations. The Al4C3 nanorods were homogeneously dispersed and possessed an intimate and faceted interface with the matrix, resulting in the enhanced tensile strength of Al. Moreover, the Al4C3/Al composite retained the required electrical conductivity similar to that of pure Al, in addition to the stable interface at elevated temperatures and long-term service reliability in moist environment. The findings of this study will be significant in providing the basis of designing novel heat-resistant AMCs in electrical applications.

Poor oxidation resistance is a longstanding disadvantage of Mo-based materials for ultrahigh-temperature applications. In this study, we developed a facile strategy for depositing an in-situ ceramic layer on the surface of Mo-based composites via laser powder bed fusion (L-PBF) using Mo-based alloy powders covered with uniform Al2O3 nanoparticles and bridged by functionalized carbon nanotubes. The surface layer consisted of an α-Al2O3 matrix with a dispersed TiC phase and had a controllable thickness. The formation mechanism of this layer was investigated systematically through single-track observations and finite-element simulation. Moreover, the increased nanohardness can be attributed to the uniformly dispersed, intimately contacted ceramic nanoparticles in the matrix. The results indicated the multifunctionality of L-PBF-processed metallic parts, introducing the possibility of fabricating advanced ultrahigh-temperature materials.

A novel Mo-based composite with simultaneously improved mechanical and oxidation properties was fabricated by laser powder bed fusion (L-PBF), using uniform Al2O3-nanoparticle-decorated MoTiAl powders bridged by functionalized carbon nanotubes. A tight ceramic coating ∼2.57 μm in thickness consisting of an α-Al2O3 matrix with dispersed TiC particles was formed on the surface of the Al2O3-CNT/MoTiAl composite, which has been proved to effectively increase resistance to oxidation at 1173 K. Meanwhile, the nanoparticles were homogenously dispersed and tightly contacted with the matrix, giving rise to an enhanced Vickers hardness. This work shed light on designing and producing high-performance Mo-based composites for application to ultrahigh-temperature materials.

Background Rice is a major source of dietary intake of arsenic (As) for the populations that consume rice as a staple food. Therefore, it is necessary to reduce the As concentration in rice to avoid the potential risk to human health. In this study, the genetic diversity in As accumulation and As speciation in rice grains was investigated using a world rice core collection (WRC) comprising 69 accessions grown over a 3-year period. Moreover, quantitative trait locus (QTL) analysis was conducted to identify QTLs controlling the dimethylarsinic acid (DMA) content of rice grains. Results There was a 3-fold difference in the grain As concentration of WRC. Concentrations of total-As, inorganic As, and DMA were significantly affected by genotype, year, and genotype-year interaction effects. Among the WRC accessions, Local Basmati and Tima (indica type) were identified as cultivars with the lowest stable total-As and inorganic As concentrations. Using an F2 population derived from Padi Perak (a high-DMA accession) and Koshihikari (a low-DMA cultivar), we identified two QTLs on chromosome 6 (qDMAs6.1 and qDMAs6.2) and one QTL on chromosome 8 (qDMAs8) that were responsible for variations in the grain DMA concentration. Approximately 73% of total phenotypic variance in DMA was explained by the three QTLs. Conclusions Based on the results provided, one strategy for developing rice cultivars with a low level of toxic As would be to change the proportion of organic As on the basis of a low level of total As content. Electronic supplementary material The online version of this article (doi:10.1186/1939-8433-6-3) contains supplementary material, which is available to authorized users.

Acute Myeloid Leukemia (AML) with MLL gene rearrangements demonstrate unique gene expression profiles driven by MLL-fusion proteins. Here, we identify the circadian clock transcription factor SHARP1 as a novel oncogenic target in MLL-AF6 AML, which has the worst prognosis among all subtypes of MLL-rearranged AMLs. SHARP1 is expressed solely in MLL-AF6 AML, and its expression is regulated directly by MLL-AF6/DOT1L. Suppression of SHARP1 induces robust apoptosis of human MLL-AF6 AML cells. Genetic deletion in mice delays the development of leukemia and attenuated leukemia-initiating potential, while sparing normal hematopoiesis. Mechanistically, SHARP1 binds to transcriptionally active chromatin across the genome and activates genes critical for cell survival as well as key oncogenic targets of MLL-AF6. Our findings demonstrate the unique oncogenic role for SHARP1 in MLL-AF6 AML., Gene fusions involving MLL and different partner genes define unique subgroups of acute myelogenous leukemia, but the mechanisms underlying specific subgroups are not fully clear. Here the authors elucidate the mechanisms of MLL-AF6 induced transformation, providing a distinct pathway that involves SHARP1 as a critical target.

We aim to prepare monodispersed and homogenous spherical particles of pure Fe76Si9B10P5 metallic glass with a low content of nucleation sites, and to evaluate the intrinsic glass-forming ability of Fe76Si9B10P5 alloys by containerless solidification. Monodispersed Fe76Si9B10P5 particles were successfully prepared by our originally developed pulsated orifice ejection method under He and Ar gas atmosphere. All obtained particles, with diameters ranging from 313 to 664 μm, were identified as single glassy or amorphous phases by X-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The critical cooling rate to form the fully glassy or amorphous phase was estimated in less than 550 K/s by a Newtonian cooling model. The results show that the Fe76Si9B10P5 alloy has sufficient glass-forming ability under restrained nucleation conditions.

Graphene is an ultra-thin, remarkably flexible and highly stiff 2D material that can profoundly change the microstructure of composite as filler phase, giving rise to mechanical properties greatly different from traditional composites. However, there are very few examples that demonstrate the exceptional properties in graphene based ceramic composite because of the tradeoff between small thickness of graphene platelet and dispersion uniformity in processing. Here, a fully dense Al 2 O 3 composite with uniformly dispersed few-layer graphene (FLG) is prepared by heteroaggregation technique and spark plasma sintering. It is found that in comparison to monolithic Al 2 O 3 , drastically reduced Young’s modulus (298 GPa), completely retained fracture strength (417 MPa) and enhanced fracture toughness (5.3 MPa m 1/2 ) are simultaneously realized in this composite, leading to an unprecedented increase of strain tolerance by ∼40% at merely 2.18 vol.% of filler loading. It is believed that the unique highly wrinkled structure of FLG at triple junctions of ceramic matrix causes the inefficient load transfer before crack initiation and thus low stiffness in composite. Whereas after crack initiation, by the “stretched filler bridging” of FLG platelet behind crack tip, the toughness of composite is enhanced so that the high fracture strength can be retained.

Wnt signaling controls early embryonic hematopoiesis and dysregulated β-catenin is implicated in leukemia. However, the role of Wnts and their source in adult hematopoiesis is still unclear, and is clinically important as upstream Wnt inhibitors enter clinical trials. We blocked Wnt secretion in hematopoietic lineages by targeting Porcn, a membrane-bound O-acyltransferase that is indispensable for the activity and secretion of all vertebrate Wnts. Surprisingly, deletion of Porcn in Rosa-CreER(T2)/Porcn(Del), MX1-Cre/Porcn(Del), and Vav-Cre/Porcn(Del) mice had no effects on proliferation, differentiation, or self-renewal of adult hematopoietic stem cells. Targeting Wnt secretion in the bone marrow niche by treatment with a PORCN inhibitor, C59, similarly had no effect on hematopoiesis. These results exclude a role for hematopoietic PORCN-dependent Wnts in adult hematopoiesis. Clinical use of upstream Wnt inhibitors is not likely to be limited by effects on hematopoiesis.

Doping of graphene by contacting other materials has significant meaning to the graphene based devices and composites. In this work, highly conducting few-layer graphene (FLG) based composites in which the doping type and level can be manipulated by incorporating FLG with different matrixes are fabricated. Three metal oxides with different level of oxygen vacancies (α-Al 2 O 3 , 3%mol yttria stabilized zirconia (3YSZ) and 8%mol yttria stabilized zirconia (8YSZ)) are selected as matrix material. While the electrical conductivity is largely enhanced to 1.4 × 10 3 –2.1 × 10 3 Sm −1 in the composites by adding 4.42–5.1 vol.% FLG, hole-doping level in composites increases in the sequence of FLG/Al 2 O 3

A low magnetic Zr-1Mo alloy was fabricated by a powder bed fusion (PBF) process using a fiber laser. The microstructure, surface morphology, and pore distribution of the as-built Zr-1Mo alloy were observed. Its magnetic susceptibility and Vickers hardness were evaluated by magnetic susceptibility balance and a microindentation tester, respectively. The as-built Zr-1Mo alloy mainly consisted of an α′ phase with an acicular structure. From the processing maps of the surface morphology and pore distribution, open pores on the top surface due to the lack of fusion corresponded to grid-like distributed pores, and large pores corresponded to balling particles on the top surface. The Vickers hardness was influenced by the oxygen and nitrogen contents rather than the porosity. The magnetic susceptibilities of the as-built Zr-1Mo alloy still were one-third those of Ti-6Al-4V and Ti-6Al-7Nb, thus PBF can be applicable to the fabrication process for the low magnetic Zr-1Mo alloy.

Selective laser melting (SLM) technology was recently introduced to fabricate dental prostheses. However, the fatigue strength of clasps in removable partial dentures prepared by SLM still requires improvement. In this study, we attempted to improve the fatigue strength of clasps by adding support structures for overhanging parts, which can generally be manufactured at an angle to be self-supporting. The results show that the fatigue strength of the supported specimens was more than twice that of unsupported specimens. Electron back-scattered diffraction analysis revealed that the supported specimens exhibited lower kernel average misorientation values than the unsupported specimens, which suggested that the support structure reduced the residual strain during the SLM process and helped to prevent micro-cracks led by thermal distortion. In addition, the supported specimens cooled more rapidly, thereby forming a finer grain size compared to that of the unsupported specimens, which contributed to improving the fatigue strength. The results of this study suggest that the fatigue strength of overhanging parts can be improved by intentionally adding support structures.

Magnesium silicide (Mg2Si)/carbon nanotube (CNT) thermoelectric nanofibers for use as a flexible thermoelectric material were successfully synthesized through the combined processes of the sol-gel method, magnesiothermic reduction, and liquid-solid phase reaction. In the resulting product, each CNT was coated with Mg2Si which was an approximately 60-nm-thick single crystal. The synthesized Mg2Si-coated CNTs exhibited n-type thermoelectric behavior confirming that n-type thermoelectric composite nanofibers were successfully obtained.

Fe-based metallic glasses are difficult to plastically form into complex shapes in their supercooled liquid region because of their rather high viscosity and low thermal stability. In this study, we proposed a novel two-step fabrication process for micro components using viscous flow of an Fe-based metallic glass. First, we prepare mono-sized [(Fe0.5Co0.5)0.75 Si0.05B0.2]96Nb4 spherical particles with precisely controlled volumes that correspond to the desired micro component volume. It is essential that the prepared spherical particles be composed of a single glassy phase. Then, one prepared particle is die-pressed into one micro component under the supercooled liquid region. The main deformation mechanism is viscous flow and the micro hot-press apparatus was used to realize the optimal processing conditions for micro viscous flow. The processed micro gear maintained the fully glassy phase, resulting in excellent mechanical strength, up to 1125 HV on average by the Vicker hardness test. Crystallization of the material during processing has been discussed related to the process temperature and deformation rate using the model of Kaysser and Arzt.

Iron-based metallic glasses have attracted much attention for use as microscale components in many devices because they provide unique processability with nanoscale precision. Fe-based metallic glasses, however, do not have enough resistance against crystallization, and therefore their incubation time for crystallization is too short. To prevent crystallization, the processing temperature cannot be set too high within the supercooled-liquid region, and high processing speeds are required. Taking this into consideration, the viscoelastic properties were observed during the viscous-flow microprocessing of a single metallic glassy particle of [(Fe0.5Co0.5)0.75Si0.05B0.2]96Nb4 metallic glass to identify its relaxation behavior of on the micrometer scale during a compressive test at 833 K. The relaxation behavior is found to be well described by the Kohlrausch–Williams–Watt model. The dependence of the ratio of the viscosity to the modulus of rigidity on the compressive speed during deformation was also investigated by constructing the master curve describing the behavior of the elasticity and viscosity fractions versus the apparent relaxation time. At a compressive strain rate of 4.5 × 10−2 s−1, the Fe-based metallic supercooled liquid behaved as a viscoelastic fluid, although at a compressive strain rate of 4.5 × 10−3 s−1, its behavior was almost viscous. From the master curve, it can be concluded that the effect of the compressive speed on the ratio of the viscosity to the modulus of rigidity can clearly be observed, and the viscous-flow behavior of a [(Fe0.5Co0.5)0.75Si0.05B0.2]96Nb4 metallic supercooled liquid can be predicted at any processing speed.

The defect-type evolution and gradual increase in nanodefects in the outer walls of multiwalled carbon nanotubes (MWCNTs) in a chemically oxidizing environment were thoroughly investigated using a mixture of sulfuric acid (H2SO4) and nitric acid (HNO3). A fairly low temperature of 323 K was employed for the acid treatment, and this limited the reaction rate to provide a mild acidic environment for gradual chemical oxidation compared to commonly used treatment conditions. High-resolution transmission electron microscopy (HRTEM) observations clearly demonstrated the formation of groove-type defects in the outer walls of MWCNTs in the early period around 0.5–3 h, followed by a morphological change into circumference-type defects and further into unzipped graphene nanoribbons. A unique parabolic variation in the intensity ratio of D and G bands (ID/IG) was observed. This observation supports the gradual oxidation of graphitic walls with increasing acid treatment time and corresponds well with the formation and evolution of nanodefects. Herein, the appropriate acid treatment time that would result in an effective number of nanodefects via suitable carboxyl functionalization, providing preferential nanocarbide sites for interfacial improvement as well as uniform dispersibility of MWCNTs, has been discussed.

Functionally graded (FG) carbon nanotubes (CNT) and nano-silicon carbide (nSiC) reinforced aluminium (Al) matrix composites have been successfully fabricated using high-energy ball milling followed by solid-state spark plasma sintering processes. The CNTs were well-dispersed in the Al particles using the nSiC as a solid mixing agent. Two different types of multi-walled CNTs were used to add different amounts of CNTs in the same volume. The ball milled Al–CNT–nSiC and Al–CNT powder mixtures were fully densified and demonstrated good adhesion with no serious microcracks and pores within an FG multilayer composite. Each layer contained different amounts of the CNTs, and the nSiC additions showed different microstructures and hardness. It is possible to control the characteristics of the FG multilayer composite through the efficient design of an Al–CNT–nSiC gradient layer. This concept offers a feasible approach for fabricating the dual-nanoparticulate-reinforced Al matrix nanocomposites and can be applied to other scenarios such as polymer and ceramic systems.

International audience; The constant increase in power and heat flux densities encountered in electronic devices fuels a rising demand for lightweight heat sink materials with suitable thermal properties. In this study, discontinuous pitch-based carbon fiber reinforced aluminum matrix (Al-CF) composites with aluminum-silicon alloy (Al-Si) were fabricated through hot pressing. The small amount of Al-Si contributed to enhance the sintering process in order to achieve fully dense Al-CF composites. A thermal conductivity and CTE of 258 W/(m K) and 7.0 9 10-6 /K in the in-plane direction of the carbon fibers were obtained for a (Al 95 vol% ? Al-Si 5 vol%)-CF 50 vol% composite. Carbon fiber provides the reducing of CTE while the conservation of thermal conductivity and weight of Al. The achieved CTEs satisfy the standard requirements for a heat sink material, which furthermore possess a specific thermal conductivity of 109 W cm 3 /(m K g). This simple process allows the low-cost fabrication of Al-CF composite, which is applicable for a lightweight heat sink material.

Fully dense few-layer graphene (FG)/Al 2 O 3 nanocomposites with homogeneously dispersed FG in matrix are prepared by using a heteroaggregation method followed by spark plasma sintering. It is found that the two dimensional FG has great ability to restrain grain growth in comparison to other inclusions. In addition, the morphology of grain in composite is modified by the addition of FG during densification process compared with monolithic alumina. Thanks to the greatly decreased grain size, the composites are almost as hard as monolithic alumina at low sintering temperature (1573 K) even if graphene content is as high as 1.2 vol.%. However, at higher sintering temperature (1673 K), the hardness of composites decreases further but the change in elastic modulus is very limited. The decline of hardness and elastic modulus mainly arises from the sliding feature of FG, low modulus of reduced graphene oxide in both in-plane and out-of-plane directions.

The crystalline integrity of multi-walled carbon nanotubes (MWCNTs) plays a critical role in determining the performance of MWCNT/Al composites. In this work, the structural evolution of MWCNTs during composite consolidation was studied via high-resolution transmission electron microscopy and Raman spectroscopy. The MWCNTs were not structurally damaged during the spark plasma sintering of MWCNT/Al mixed powders. However, two kinds of fractures, i.e., clear break and sword-in-sheath failure, were generated under severe plastic deformation of Al during hot extrusion. We concluded that the MWCNT failure, seen on the fractured composites, was caused by the consolidation process rather than the tensile tests. This work provides a better understanding of the strengthening behavior of MWCNTs, and the design of high-performance MWCNT/Al composites using suitable consolidation techniques.

BackgroundHepatocellular carcinoma is the third leading cause of cancer-related deaths worldwide. In the heterogeneous group of hepatocellular carcinomas, those with characteristics of embryonic stem-cell and progenitor-cell gene expression are associated with the worst prognosis. The oncofetal gene SALL4, a marker of a subtype of hepatocellular carcinoma with progenitor-like features, is associated with a poor prognosis and is a potential target for treatment.MethodsWe screened specimens obtained from patients with primary hepatocellular carcinoma for the expression of SALL4 and carried out a clinicopathological analysis. Loss-of-function studies were then performed to evaluate the role of SALL4 in hepatocarcinogenesis and its potential as a molecular target for therapy. To assess the therapeutic effects of a peptide that targets SALL4, we used in vitro functional and in vivo xenograft assays.ResultsSALL4 is an oncofetal protein that is expressed in the human fetal liver and silenced in the adult liver, but it is reexpressed in a subgroup of patients who have hepatocellular carcinoma and an unfavorable prognosis. Gene-expression analysis showed the enrichment of progenitor-like gene signatures with overexpression of proliferative and metastatic genes in SALL4-positive hepatocellular carcinomas. Loss-offunction studies confirmed the critical role of SALL4 in cell survival and tumorigenicity. Blocking SALL4–corepressor interactions released suppression of PTEN (the phosphatase and tensin homologue protein) and inhibited tumor formation in xenograftmodels in vivo.ConclusionsSALL4 is a marker for a progenitor subclass of hepatocellular carcinoma with anaggressive phenotype. The absence of SALL4 expression in the healthy adult liver enhances the potential of SALL4 as a treatment target in hepatocellular carcinoma. (Funded by the Singapore National Medical Research Council and others.)

We investigate the high-temperature compressive deformation behavior of a novel, fully dense and structurally uniform, 20 vol% multiwalled carbon nanotube (MWCNT)–α-Al2O3 matrix hybrid, which has a strong room-temperature interfacial shear resistance (ISR) and a unique MWCNT-concentrated grain-boundary (GB) structure. We realized a perfect plastic deformation at 1400°C and a rather high initial strain rate of 10−4 s−1 by a low ~30 MPa flow stress, which is contrary to the strain hardening response of fine-grain monolithic Al2O3. This unique performance in CNT–ceramic system in compression is explained as follows: the concentrated network of individual MWCNTs perfectly withstands the high-temperature and shear/compressive forces, and strongly preserves the nanostructure of Al2O3 matrix by preventing the dynamic grain growth, even during a large ~44% deformation. Furthermore, the presence of large amount of radially soft/elastic, highly energy-absorbing MWCNTs in the GB and specially multiple junction areas, and a potentially weak 1400°C-ISR, could greatly facilitate the GB sliding process (despite the hybrid's strong room-temperature ISR), as evidenced by the formation of some submicrometer-scale MWCNT aggregates in GB area, the equiaxed grains and dislocation-free nanostructure of the deformed hybrid. The results presented here could be attractive for the ceramic forming industry and could be regarded as a reference for oxide systems in which, the GB areas are occupied with soft/elastic, highly energy-absorbing nanostructures.

This research describes an investigation of the interfacial phases formed between aluminum (Al) and carbon nanotubes (CNT) which properties depend on the processing temperature (below, slightly above and over the melting point of Al). Al–CNT compacts were prepared by spark plasma sintering followed by heat treatment in order to observe the interface phases. The microstructures of both the as-sintered and heat-treated materials have been observed by optical, scanning and transmission electron microscopies. The amorphous Al oxide observed at the boundaries in the as-sintered material is transformed to crystalline Al oxide after the heat treatment. In addition, some of the CNTs decomposed and reacted with the Al, resulting in the formation of Al carbide which shows different size distributions depending on the heat treatment temperature. According to the results, it is possible to control the phase formed at the Al–CNT interface by controlling the process temperature and those controlled interfaces will be playing important role to the properties in a bulk materials.

Al2O3 matrix composites reinforced with Ba-b-Al2O3 phase were synthesized through reactive sintering using Al2O3 and BaCO3 as starting powders. Dense Al2O3/Ba-b-Al2O3 composites can be obtained by spark plasma sintering from Al2O3/BaO•Al2O3 powder, which was prepared by calcining Al2O3/BaCO3 powder mixture. The Ba-b-Al2O3 reinforcing phase exhibited an elongated morphology due to preferred diffusion of Ba cations. The existence of Ba-b-Al2O3 phase as well as low sintering temperature and short holding time during reactive sintering inhibit grain growth and thus result in small grain sizes of the Al2O3 matrix.

Functionally graded materials (FGMs) are compositionally gradient materials. They can achieve the controlled distribution of the desired characteristics within the same bulk material. We describe a functionally graded (FG) metal-phosphor adapting the concept of the FGM; copper (Cu) is selected as a metal and Cu- and Cl-doped ZnS (ZnS:Cu,Cl) is selected as a phosphor and FG [Cu]-[ZnS:Cu,Cl] is fabricated by a very simple powder process. The FG [Cu]-[ZnS:Cu,Cl] reveals a dual-structured functional material composed of dense Cu and porous ZnS:Cu,Cl, which is completely combined through six graded mediating layers. The photoluminescence (PL) of FG [Cu]-[ZnS:Cu,Cl] is insensitive to temperature change. FG [Cu]-[ZnS:Cu,Cl] also exhibits diode characteristics and photo reactivity for 365 nm -UV light. Our FG metal-phosphor concept can pave the way to simplified manufacturing of low-cost and can be applied to various electronic devices.

A new method for determining the viscosity of the supercooled liquid region of metallic glasses by means of a single-particle compressive test (SPCT) is proposed. A spherical metallic glassy particle several hundred micrometers in diameter is uniaxially pressed using a precisely controlled micro-hot-pressing system. Assuming viscous flow of the material, we derived the viscosity as a function of compressive load and displacement under a constant crosshead speed. SPCT is effective in evaluating metallic glass viscosity regardless of glass forming capability.