Tuning the hysteresis of a metal-insulator transition via lattice compatibility.

Structural phase transitions serve as the basis for many functional applications including shape memory alloys (SMAs), switches based on metal-insulator transitions (MITs), etc. In such materials, lattice incompatibility between transformed and parent phases often results in a thermal hysteresis, which is intimately tied to degradation of reversibility of the transformation. The non-linear theory of martensite suggests that the hysteresis of a martensitic phase transformation is solely determined by the lattice constants, and the conditions proposed for geometrical compatibility have been successfully applied to minimizing the hysteresis in SMAs. Here, we apply the non-linear theory to a correlated oxide system (V1-xWxO2), and show that the hysteresis of the MIT in the system can be directly tuned by adjusting the lattice constants of the phases. The results underscore the profound influence structural compatibility has on intrinsic electronic properties, and indicate that the theory provides a universal guidance for optimizing phase transforming materials.

Japanese civilian and US military interaction in the evacuation of casualties from Camp Fuji.

Historically, if US soldiers at Camp Fuji become severely ill or suffer trauma, they are transported by the ground ambulance, as the doctor-led air ambulance in eastern Shizuoka has never been permitted to land at Camp Fuji. However, it is widely recognised that severely ill or traumatised patients require time-dependent medical management. It was therefore agreed to undertake a joint exercise between the US medical assets of Camp Fuji and the doctor helicopters in eastern Shizuoka prefecture in evacuating a simulated severely ill or traumatised US soldier. The aim of this article is to describe the background and rationale between this collaboration between the civilian Japanese air ambulance and the US medical assets in Camp Fuji.

Development and analysis of patient-derived xenograft mouse models in intravascular large B-cell lymphoma.

Intravascular large B-cell lymphoma (IVLBCL) is a distinct disease entity with the peculiar characteristic that tumor cells proliferate within vessels. Despite recent advances in understanding the disease from clinical aspects, the underlying pathogenesis remains unknown. Here we demonstrate analyses of IVLBCL biology using four xenograft mouse models established from primary IVLBCL samples. In all four models, the main characteristic of IVLBCL tumor cell proliferation within vessels was retained. Time-lapse engraftment analyses revealed that the tumor cells initially engrafted and proliferated in the sinusoids and vessels in the liver and then engrafted and proliferated in multiple organs. Intriguingly, serial passage of tumor cells from the adrenal gland of a transplanted mouse developed from primary patient bone marrow cells into a second mouse showed that the tumor cells mainly distributed into the adrenal gland in the second mouse, implying the existence of clonal selection and/or evolution at engraftment of a specific organ. Gene expression profiling analyses demonstrated that the gene set associated with cell migration was enriched for normal peripheral blood B cells, indicating that inhibition of cell migration might be involved in IVLBCL pathogenesis. In conclusion, the mouse xenograft models described here are essential tools for uncovering IVLBCL biology.

Structural study of epitaxial LiCoO2 films grown by pulsed laser deposition on single crystal SrTiO3 substrates.

Epitaxial LiCoO2 (LCO) thin films of different orientations were fabricated by pulsed laser deposition (PLD) in order to model single-crystal behavior of intercalation cathodes during electrochemical reactions. This paper demonstrates that (1) epitaxial growth of LCO on a single crystal Nb-doped SrTiO3 (Nb:STO) of different orientations occurs with a single orientation relationship; (2) surface morphology of the LCO films is established by the morphology of coalescing grains during island growth mode, whereas morphology of the grains can be visualized as different cuts from a cube with low-energy {104}R-LCO surfaces; (3) the films consist of predominately trigonal R-LiCoO2 phase, with a small fraction of the occasionally present cubic c-LixCoO2 phase; (4) cyclic voltammetry measurements have determined rectification at interface between LCO and Nb:STO causing bias on the oxidation part of cycling, thus preventing full cycling.

High-throughput determination of structural phase diagram and constituent phases using GRENDEL.

Advances in high-throughput materials fabrication and characterization techniques have resulted in faster rates of data collection and rapidly growing volumes of experimental data. To convert this mass of information into actionable knowledge of material process-structure-property relationships requires high-throughput data analysis techniques. This work explores the use of the Graph-based endmember extraction and labeling (GRENDEL) algorithm as a high-throughput method for analyzing structural data from combinatorial libraries, specifically, to determine phase diagrams and constituent phases from both x-ray diffraction and Raman spectral data. The GRENDEL algorithm utilizes a set of physical constraints to optimize results and provides a framework by which additional physics-based constraints can be easily incorporated. GRENDEL also permits the integration of database data as shown by the use of critically evaluated data from the Inorganic Crystal Structure Database in the x-ray diffraction data analysis. Also the Sunburst radial tree map is demonstrated as a tool to visualize material structure-property relationships found through graph based analysis.

Anomalous magnetoresistance in the spinel superconductor LiTi2O4.

LiTi2O4 is a unique compound in that it is the only known spinel oxide superconductor. The lack of high quality single crystals has thus far prevented systematic investigations of its transport properties. Here we report a careful study of transport and tunnelling spectroscopy in epitaxial LiTi2O4 thin films. An unusual magnetoresistance is observed which changes from nearly isotropic negative to prominently anisotropic positive as the temperature is decreased. We present evidence that shows that the negative magnetoresistance likely stems from the suppression of local spin fluctuations or spin-orbit scattering centres. The positive magnetoresistance suggests the presence of an orbital-related state, also supported by the fact that the superconducting energy gap decreases as a quadratic function of magnetic field. These observations indicate that the spin-orbital fluctuations play an important role in LiTi2O4 in a manner similar to high-temperature superconductors.

Atomic-scale evolution of modulated phases at the ferroelectric-antiferroelectric morphotropic phase boundary controlled by flexoelectric interaction.

Physical and structural origins of morphotropic phase boundaries (MPBs) in ferroics remain elusive despite decades of study. The leading competing theories employ either low-symmetry bridging phases or adaptive phases with nanoscale textures to describe different subsets of the macroscopic data, while the decisive atomic-scale information has so far been missing. Here we report direct atomically resolved mapping of polarization and structure order parameter fields in a Sm-doped BiFeO(3) system and their evolution as the system approaches a MPB. We further show that both the experimental phase diagram and the observed phase evolution can be explained by taking into account the flexoelectric interaction, which renders the effective domain wall energy negative, thus stabilizing modulated phases in the vicinity of the MPB. Our study highlights the importance of local order-parameter mapping at the atomic scale and establishes a hitherto unobserved physical origin of spatially modulated phases existing in the vicinity of the MPB.

In situ observation of reversible nanomagnetic switching induced by electric fields.

We report direct observation of controlled and reversible switching of magnetic domains using static (dc) electric fields applied in situ during Lorentz microscopy. The switching is realized through electromechanical coupling in thin film Fe(0.7)Ga(0.3)/BaTiO(3) bilayer structures mechanically released from the growth substrate. The domain wall motion is observed dynamically, allowing the direct association of local magnetic ordering throughout a range of applied electric fields. During application of approximately 7-11 MV/m electric fields to the piezoelectric BaTiO(3) film, local magnetic domains rearrange in the ferromagnetic Fe(0.7)Ga(0.3) layer due to the transfer of strain from the BaTiO(3) film. A simulation based on micromagnetic modeling shows a magnetostrictive anisotropy of 25 kPa induced in the Fe(0.7)Ga(0.3) due to the strain. This electric-field-dependent uniaxial anisotropy is proposed as a possible mechanism to control the coercive field during operation of an integrated magnetoelectric memory node.

Rapid identification of structural phases in combinatorial thin-film libraries using x-ray diffraction and non-negative matrix factorization.

In this work we apply a technique called non-negative matrix factorization (NMF) to the problem of analyzing hundreds of x-ray microdiffraction (microXRD) patterns from a combinatorial materials library. An in-house scanning x-ray microdiffractometer is used to obtain microXRD patterns from 273 different compositions on a single composition spread library. NMF is then used to identify the unique microXRD patterns present in the system and quantify the contribution of each of these basis patterns to each experimental diffraction pattern. As a baseline, the results of NMF are compared to the results obtained using principle component analysis. The basis patterns found using NMF are then compared to reference patterns from a database of known structural patterns in order to identify known structures. As an example system, we explore a region of the Fe-Ga-Pd ternary system. The use of NMF in this case reduces the arduous task of analyzing hundreds of microXRD patterns to the much smaller task of identifying only nine microXRD patterns.

An infrared imaging method for high-throughput combinatorial investigation of hydrogenation-dehydrogenation and new phase formation of thin films.

We have developed an infrared imaging setup enabling in situ infrared images to be acquired, and expanded on capabilities of an infrared imaging as a high-throughput screening technique, determination of a critical thickness of a Pd capping layer which significantly blocks infrared emission from below, enhancement of sensitivity to hydrogenation and dehydrogenation by normalizing raw infrared intensity of a Mg thin film to an inert reference, rapid and systematic screening of hydrogenation and dehydrogenation properties of a Mg-Ni composition spread covered by a thickness gradient Pd capping layer, and detection of formation of a Mg2Si phase in a Mg thin film on a thermally oxidized Si substrate during annealing.

Genome-wide analysis of DNA copy number alterations and gene expression in gastric cancer.

Genomic copy number aberrations (CNAs) are believed to play a major role in the development and progression of human cancers. Although many CNAs have been reported in gastric cancer, their genome-wide transcriptional consequences are poorly understood. In this study, to reveal the impact of CNAs on genome-wide expression in gastric cancer, we analysed 30 cases of gastric cancers for their CNAs by array comparative genomic hybridization (array CGH) and 24 of these 30 cases for their expression profiles by oligonucleotide-expression microarray. We found that with the application of laser microdissection, most CNAs were detected at higher frequency than in previous studies. Notably, gain at 20q13 was detected in almost all cases (97%), suggesting that this may play an important role in the pathogenesis of gastric cancer. By comparing the array CGH data with expression profiles of the same samples, we showed that both genomic amplification and deletion strongly influence the expression of genes in altered genomic regions. Furthermore, we identified 125 candidate genes, consisting of 114 up-regulated genes located in recurrent regions (>10%) of amplification and 11 down-regulated genes located in recurrent regions of deletion. Up-regulation of several candidate genes, such as CDC6, SEC61G, ANP32E, BYSL and FDFT1, was confirmed by immunohistochemistry. Interestingly, some candidate genes were localized at genomic loci adjacent to well-known genes such as EGFR, ERBB2 and SMAD4, and concordantly deregulated by genomic alterations. Based on these results, we propose that our list of candidate genes may contain novel genes involved in the pathogenesis of advanced gastric cancer.

High-resolution analysis of DNA copy number alterations and gene expression in renal clear cell carcinoma.

We analysed chromosomal copy number aberrations (CNAs) in renal cell carcinomas by array-based comparative genomic hybridization, using a genome-wide scanning array with 2304 BAC and PAC clones covering the whole human genome at a resolution of roughly 1.3 Mb. A total of 30 samples of renal cell carcinoma were analysed, including 26 cases of clear cell carcinoma (CCC) and four cases of chromophobe renal cell carcinoma (ChCC). In CCCs, gains of chromosomes 5q33.1-qter (58%), 7q11.22-q35 (35%) and 16p12.3-p13.12 (19%), and losses of chromosomes 3p25.1-p25.3 (77%), 3p21.31-p22.3 (81%), 3p14.1-p14.2 (77%), 8p23.3 (31%), 9q21.13-qter (19%) and 14q32.32-qter (38%) were detected. On the other hand, the patterns of CNAs differed markedly between CCCs and ChCCs. Next, we examined the correlation of CNAs with expression profiles in the same tumour samples in 22/26 cases of CCC, using oligonucleotide microarray. We extracted genes that were differentially expressed between cases with and without CNAs, and found that significantly more up-regulated genes were localized on chromosomes 5 and 7, where recurrent genomic gains have been detected. Conversely, significantly more down-regulated genes were localized on chromosomes 14 and 3, where recurrent genomic losses have been detected. These results revealed that CNAs were correlated with deregulation of gene expression in CCCs. Furthermore, we compared the patterns of genomic imbalance with histopathological features, and found that loss of 14q appeared to be a specific and additional genetic abnormality in high-grade CCC. When we compared the expression profiles of low-grade CCCs with those of high-grade CCCs, differentially down-regulated genes tended to be localized on chromosomes 14 and 9. Thus, it is suggested that copy number loss at 14q in high-grade CCC may be involved in the down-regulation of genes located in this region.

Rapid structural mapping of ternary metallic alloy systems using the combinatorial approach and cluster analysis.

We are developing a procedure for the quick identification of structural phases in thin film composition spread experiments which map large fractions of compositional phase diagrams of ternary metallic alloy systems. An in-house scanning x-ray microdiffractometer is used to obtain x-ray spectra from 273 different compositions on a single composition spread library. A cluster analysis software is then used to sort the spectra into groups in order to rapidly discover the distribution of phases on the ternary diagram. The most representative pattern of each group is then compared to a database of known structures to identify known phases. Using this method, the arduous analysis and classification of hundreds of spectra is reduced to a much shorter analysis of only a few spectra.

Development of the walking support robot with the weight bearing mechanism supporting ischia--cushion for ischia and behavior of ischia during walking.

This report describes the cushion suitable for weight bearing mechanism supporting ischia and the behavior of ischia during walking. Hitachi Ltd. developed the power-assisted walking support device and the walk training machine with weight bearing mechanisms using a hip orthosis and a saddle. Because user's weight is centered on symphysis pubica, users feel sore and it is obstacle to smooth walking. Then, we propose a new weight bearing mechanism supporting ischia. Because an interface between human and robot is important, we experimented on the cushion for ischia that is the interface between human and the weight bearing mechanism supporting ischia. In the experiment, we measured seating pressure, the trajectory of the seating pressure's center, position of ischia, and force on the weight bearing arm when a user was walking while locating his hip on the cushion for ischia. The result shows that the seating cushion is suited for the interface, but it is also necessary to support separately each ischium's up down movement and rotating movement during walking.

Comparison of the effects of gasless procedure, CO2-pneumoperitoneum, and laparotomy on splenic and hepatic natural killer activity in a rat model.

BACKGROUND: Natural killer (NK) activity plays an important role in the prevention of tumor metastasis. However, few studies compared changes in NK activities between gas(less) laparoscopy and open surgery. MATERIALS AND METHODS: Donryu rats were randomized to 4 groups ( n = 6-9, for each lime point in each group): gasless group, pneumoperitoneum group, laparotomy group, and control group. The surgical treatment groups received additional cecal resection at the end of the procedures. Spleen cells and hepatic nonparenchymal cells were harvested at 6, 24, or 96 h, to determine the splenic and hepatic NK activities against YAC-1 cells. RESULTS: Compared with the anesthesia control, laparotomy and pneumoperitoneum depressed splenic NK activity at 24 h ( p < 0.01 for laparotomy and p < 0.05, for pneumoperitoneum) and 96 h ( p < 0.05). Laparotomy also depressed hepatic NK activity at 24 h ( p < 0.05). In contrast, the gasless procedure did not show any deterioration in the splenic and hepatic NK activities. CONCLUSION: These results suggest that gasless laparoscopic surgery would be a favorable approach in terms of the preservation of NK activities.

Distribution of intrasplenically injected colon cancer cells following pneumoperitoneum in mice.

BACKGROUND: Few studies have examined tumor cell distribution following laparoscopic surgery for colorectal cancer. We examined the effect of carbon dioxide pneumoperitoneum on the distribution of intrasplenically injected colon cancer cells in mice. METHODS: Mice were intrasplenically injected with 2 x 10(4) colon 26 cells labeled with 111In-oxine and were randomized to undergo pneumoperitoneum at 10 mmHg for 30 min or to receive no treatment other than anesthesia. Radioactivity of the liver, lungs, and spleen was measured 30, 60, 90, or 150 min following tumor inoculation. RESULTS: The dynamic changes in the hepatic radioactivity were not similar between groups. However, the values were not significantly different at any time point. The radioactivity of lungs was extremely low in both groups throughout the experimental period. CONCLUSIONS: Pneumoperitoneum does not appear to cause the accumulation of intraportally spreading tumor cells in the liver, but it may affect the dynamic changes of tumor cells. Also, tumor cell localization in the lungs is negligible in both pneumoperitoneum and control groups.

Identification of novel compositions of ferromagnetic shape-memory alloys using composition spreads.

Exploration of new ferroic (ferroelectric, ferromagnetic or ferroelastic) materials continues to be a central theme in condensed matter physics and to drive advances in key areas of technology. Here, using thin-film composition spreads, we have mapped the functional phase diagram of the Ni-Mn-Ga system whose Heusler composition Ni(2)MnGa is a well known ferromagnetic shape-memory alloy. A characterization technique that allows detection of martensitic transitions by visual inspection was combined with quantitative magnetization mapping using scanning SQUID (superconducting quantum interference device) microscopy. We find that a large, previously unexplored region outside the Heusler composition contains reversible martensites that are also ferromagnetic. A clear relationship between magnetization and the martensitic transition temperature is observed, revealing a strong thermodynamical coupling between magnetism and martensitic instability across a large fraction of the phase diagram.

Increased insufflation pressure enhances the development of liver metastasis in a mouse laparoscopy model: possible mechanisms.

BACKGROUND: The effect of different insufflation pressures and durations of CO2 pneumoperitoneum on the growth of liver metastasis was investigated in a mouse model. The possible mechanisms involved in the pressure-related enhancement of liver metastasis were also examined. METHODS: Mice inoculated intraportally with colon 26 cells underwent CO2 pneumoperitoneum at different pressures (5,10, or 15 mmHg) for 30 or 60 min, or received no treatment other than tumor cell inoculation (control). The subsequent growth of liver metastases was examined. Mice injected intraportally with 111In-oxine-labeled colon 26 cells underwent pneumoperitoneum at three different pressures or served as controls. The radioactivity of the liver was determined to evaluate tumor accumulation in the liver. Mice received pneumoperitoneum at three different pressures or received trocar placement alone. Changes in plasma interleukin-6 levels were determined. RESULTS: The growth of liver metastases on day 14 was influenced by increased insufflation pressures (p < 0.05) rather than the prolonged duration of pneumoperitoneum without significant interaction. The 15-mmHg pneumoperitoneum group showed a higher (p < 0.05) accumulation of radioactivity in the liver compared with the 5-mmHg pneumoperitoneum group and controls. Pneumoperitoneum groups with 5 and 10 mmHg showed higher (p < 0.05) peak levels of IL-6 compared with controls. CONCLUSIONS: An elevated insufflation pressure plays an important role in the enhancement of liver metastases, and this pressure-related adverse effect may be partly relevant to facilitating accumulation of tumor cells in the liver.

Liver metastases are less established after gasless laparoscopy than after carbon dioxide pneumoperitoneum and laparotomy in a mouse model.

BACKGROUND: Although the liver is the most frequent site of cancer recurrence after conventional open surgery for colorectal cancer, the effect of laparoscopic procedures with or without gas insufflation on the development of liver metastases is largely unknown. METHODS: Male BALB/C mice inoculated intraportally with colon 26 cells were randomized to undergo carbon dioxide pneumoperitoneum (n = 14), abdominal wall lifting (n = 14), or full laparotomy (n = 12), or to serve as control subjects without any procedures other than tumor inoculation (n = 13). RESULTS: The growth of liver metastases 14 days after surgery was enhanced after full laparotomy (p < 0.01) and pneumoperitoneum (p = 0.02), as compared with that in the control subjects, whereas there was no difference in the growth of liver metastases between abdominal wall lifting and the control condition (p = 0.99). CONCLUSIONS: These results suggest that the defense against liver metastasis is better preserved after the gasless procedure than after laparotomy and carbon dioxide pneumoperitoneum in the reported animal model.

[Effect of peroral doxifluridine plus hepatic arterial infusion for synchronous liver metastasis of colorectal cancer--correlation with the expression of thymidine phosphorylase and dihydropyrimidine dehydrogenase in primary colorectal cancer lesions].

We investigated whether the efficacy of peroral doxifluridine and hepatic arterial 5-FU infusion on synchronous liver metastasis of colorectal cancer could be predicted based on the expression of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) in the primary colorectal lesions. Ten patients with synchronous liver metastasis of colorectal cancer were given doxifluridine (600-800 mg/body/day) orally and 5-FU (500 mg/body, once or twice a week) through the hepatic artery following resection of the primary lesions between June 1996 and July 2001. The levels of TP and DPD in the primary lesions were determined by an enzyme-linked immunosorbent assay. The level of TP, DPD, and the ratio of TP/DPD in patients with partial response (n = 4) were 89.8 +/- 30.0 U/mg protein, 23.5 +/- 25.7 U/mg protein, and 3.8 +/- 1.4, respectively, while those in patients with no response or progressive disease (n = 6) were 41.8 +/- 9.7 U/mg protein, 25.8 +/- 15.8 U/mg protein, and 2.2 +/- 1.6, showing significant difference (p < 0.01) in the level of TP between the groups. These results indicate that determining the level of TS in primary colorectal lesions may be useful for predicting the efficacy of this regimen for patients with synchronous liver metastasis of colorectal cancer.