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BACKGROUND Periprocedural myocardial injury (PMI) is not an uncommon complication and is related to adverse cardiac events after percutaneous coronary intervention (PCI). We investigated the predictors of PMI in patients with stable angina pectoris (SAP) on intravascular imaging. METHODS AND RESULTS We enrolled 193 SAP patients who underwent pre-PCI intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Clinical characteristics, lesion morphology, and long-term follow-up data were compared between patients with and without PMI, defined as post-PCI elevation of high-sensitivity cardiac troponin-T. PMI were observed in 79 patients (40.9%). Estimated glomerular filtration rate (odds ratio [OR], 0.973; 95% confidence interval [CI]: 0.950-0.996; P=0.020), ≥2 stents (OR, 3.100; 95% CI: 1.334-7.205; P=0.009), final myocardial blush grade 0-2 (OR, 4.077; 95% CI: 1.295-12.839; P=0.016), and IVUS-identified echo-attenuated plaque (EA; OR, 3.623; 95% CI: 1.700-7.721; P

Background Rapidly progressive interstitial pneumonias (RPIPs) associated with clinically amyopathic dermatomyositis (CADM) are highly resistant to therapy and have a poor prognosis. Multimodal therapies, including direct hemoperfusion using a polymyxin B-immobilized fiber column (PMX-DHP), have a protective effect on RPIPs. We evaluated the effects of PMX-DHP on CADM-associated RPIPs. Methods We retrospectively enrolled 14 patients with CADM-associated RPIPs and acute respiratory failure treated with PMX-DHP, corticosteroids, and immunosuppressive agents. Clinical manifestations were compared between survivors and non-survivors at 90 days after PMX-DHP. Results The survival rate at 90 days after PMX-DHP was 35.7% (5/14). Before PMX-DHP, the survivor group exhibited a significantly higher PaO2/FiO2 (P/F) ratio and serum surfactant protein-D (SP-D) levels and significantly lower lactate dehydrogenase (LDH) and ferritin levels than the non-survivor group. Platelet counts were significantly decreased after PMX-DHP therapy in both groups, but remained higher in the survivor group than the non-survivor group over the course of treatment. Anti-melanoma differentiation-associated gene 5 (MDA-5) antibody positive patients demonstrated a poor 90-day survival rate, lower platelet counts and P/F ratio, and higher LDH levels than anti-MDA-5 antibody negative patients. Conclusions CADM-associated RPIPs with anti-MDA-5 antibody is associated with a very poor prognosis. A higher P/F ratio and SP-D level, lower LDH and ferritin levels, higher platelet counts, and anti-MDA-5 antibody negativity are important prognostic markers in patients with CADM-associated RPIPs treated with PMX-DHP.

We introduce novel irregular polar codes, which extend the regular polar coding by flexible polarization pruning. We experimentally demonstrate that the proposed polar codes outperform state-of-the-art LDPC codes, while the computational complexity in encoding and decoding can be significantly reduced by at least 30% over the regular polar codes with a marginal performance improvement.

Capecitabine is an oral fluoropyrimidine which can prolong QT interval. However, there have been no reports that capecitabine induced ventricular fibrillation (VF) due to secondary QT prolongation in patients with no structural heart disease. A 39-year-old woman developed VF during the chemotherapy of capecitabine for colon cancer. At the administration, corrected QT interval (QTc) was prolonged to 559ms despite no evidence of organic heart disease. Discontinuation of capecitabline normalized the QTc (414ms). During the follow-up of eight years, neither the QTc prolongation nor the recurrent VF has been detected. We report the rare case of capecitabine-related VF without any organic heart disease. Learning objective: Capecitabine is an oral fluoropyrimidine carbamate commonly used to treat colorectal and breast cancer. Capecitabine has been reported to be associated with VF due to vasospasm. However, capecitabine is also associated with QT elongation. This is the first report to describe VF due to capecitabine-related secondary long QT syndrome in a patient with no cardiac heart disease. Physicians must carefully follow up patients during capecitabine chemotherapy with serial electrocardiograms.>

Recent research in multidimensional modulation has shown great promise in long reach applications. In this work, we will investigate the origins of this gain, the different approaches to multidimensional constellation design, and different performance metrics for coded modulation. We will also discuss the reason that such coded modulation schemes seem to have limited application at shorter distances, and the potential for other coded modulation schemes in future transmission systems.

We propose two nonlinearity-tolerant high dimensional modulation format for 3.5 bits/symbol, which can also be an alternative for PS-QPSK (3 bits/symbol) or DP-QPSK (4 bits/symbol).

Instead of using FDTD simulations for all the inverse design steps, we proposed to use neural network-based fitting to estimate the output of the FDTD simulations, and improve the design. We observed clear acceleration in the improvement of metric.

We introduce lattice precoding (LP) as an improved version of Tomlinson-Harashima precoding (THP) for direct intensity modulation & direct detection (IM/DD) communications over plastic optical fiber (POF). We show that LP offers a significant gain greater than 5 dB over conventional methods for short-range IM/DD SI-POF systems.

Integrated indium phosphide distributed Bragg reflector lasers with on-chip optical feedback were realized and demonstrate a side-mode-suppression-ratio of 45 dB, sub-megahertz laser linewidth and an order of magnitude peak relative intensity noise reduction.

We propose a parallel cycle slip recovery method employing soft-decision slip-state estimation at pilots. Through mutual information analysis, we show that the proposed method achieves 0.6 dB gain in the presence of frequent cycle slips and strong phase noise.

We propose time domain hybrid modulation to cover 4–8 bits/symbol range, based on 5, 6, and 7 bits/symbol 4D-2A8PSK. Simulation results indicate that they have up to 1.6 dB higher span loss budget than the hybrid modulation based on conventional modulation formats in nonlinear channels.

A 1 Tb/s net bitrate transceiver using a low complexity dual-carrier architecture with free running lasers and DP-64QAM, enabled by pilot-aided DSP and low-rate LDPC, is shown to achieve transmission over 400 km with 100 km amplifier spacing.

We applied a numerical device optimization scheme, where tens of parameters can be optimized simultaneously with multiple target performance criteria that are given. The key items of the design scheme are the selection of the best optimization algorithm, metric, and consideration for fabrication errors. This method was then applied to design an MMI beam combiner with rectangular effective refractive steps with up to 75 parameters, and we obtained a simulated insertion loss of 0.8 dB for a 1.4 mm-long 2×1 wavelength combiner, and a simulated insertion loss of 4.2 dB for a 1.9 mm-long 4×1 wavelength combiner, both with 20 nm wavelength spacing. This methodology could also be applied to other types of optical devices.

The benefit from renal artery stent implantation to treat atherosclerotic renal artery stenosis (ARAS) is not well understood in hemodialysis patients. We sought to evaluate the effects of renal artery stenting on hypertension of hemodialysis patients. Renal artery stent implantation was successfully performed on eight hypertensive hemodialysis patients with ARAS (mean ± SD, 66 ± 10 years; men 6, women 2). Blood pressure was measured by automated oscillometric recordings just before hemodialysis. Mean values of the blood pressure, measured 12 times a month, were used for blood pressure analysis. Values of systolic blood pressure decreased at 6 months after renal artery stent implantation (162.6 ± 29.7 to 121.1 ± 23.3 mm Hg, p = 0.0015). Values of diastolic blood pressure also decreased from 77.6 ± 13.6 to 65.6 ± 7.2 mm Hg (p = 0.02). Renal artery stent implantation for ARAS had a beneficial effect on hypertension in hemodialysis patients.

Palladium nanoparticles dispersed in ammonium salts of hyperbranched polystyrenes are adhesively immobilized on the surface of cotton or filter papers by simply heating with dicarboxylic acids or halide anions. The resulting Pd@cotton and Pd@filter paper behave as reusable catalysts; in particular, Pd@filter paper is useful as catalyst for application to sequential cross-coupling and hydrogenation reactions to produce several different products with just one piece of the paper catalyst.

Background Lipoprotein(a) [Lp(a)] can influence the development and disruption of atherosclerotic plaques through its effect on lipid accumulation. The purpose of this study was to evaluate the relationship between serum Lp(a) levels and plaque morphology of an infarct-related lesion and non-infarct-related lesion of the coronary artery in acute myocardial infarction (AMI). Methods and results Coronary plaque morphology was evaluated in 68 patients (age 62.1±12.1 years, mean±SD; men n=58, women n=10) with AMI by intravascular ultrasound with radiofrequency data analysis before coronary intervention and by 64-slice computed tomography angiography within 2 weeks. Patients were divided into a group with an Lp(a) level of 25 mg/dl or more (n=20) and a group with an Lp(a) level of less than 25 mg/dl (n=48). Intravascular ultrasound with radiofrequency data analysis identified four types of plaque components at the infarct-related lesion: fibrous, fibrofatty, dense calcium, and necrotic core. The necrotic core component was significantly larger in the group with an Lp(a) level of 25 mg/dl or more than in the group with an Lp(a) level of less than 25 mg/dl (27.6±8.0 vs. 15.7±10.0%, P=0.0001). Coronary plaques were classified as calcified plaques, noncalcified plaques, mixed plaques, and low-attenuation plaques on 64-slice computed tomography angiography. Computed tomography indicated that the group with an Lp(a) level of 25 mg/dl or more had a greater number of total plaques, noncalcified plaques, and low-attenuation plaques in whole coronary arteries than did the group with an Lp(a) level of less than 25 mg/dl (5.3±1.8 vs. 3.7±2.2, P=0.0061; 4.0±2.0 vs. 1.2±1.3, P=0.0001; 2.2±2.1 vs. 0.5±0.7, P=0.0001, respectively). Conclusion Elevated serum Lp(a) levels are associated with the number of plaques and plaque morphology. Patients with a high Lp(a) level during AMI require more intensive treatment for plaque stabilization.

Amiodarone pulmonary toxicity (APT) is the most serious side effect of amiodarone. Although severe APT, such as ARDS, is rare, mortality of severe APT is high. Polymyxin B-immobilized fiber column direct hemoperfusion (PMX-DHP) is a medical device that reduces blood endotoxin levels in sepsis. Recent reports have shown that PMX-DHP improves oxygenation in patients with acute exacerbation of idiopathic pulmonary fibrosis and drug-induced severe interstitial pneumonia. Here, we present a case study of a patient with severe APT treated with PMX-DHP with complete recovery. The patient rapidly developed respiratory failure and required mechanical ventilation. Despite corticosteroid pulse therapy, no clinical improvement was noted. PMX-DHP was then started, and severe respiratory failure improved with reduction of serum levels of amiodarone and its metabolite monodesethylamiodarone. The patient was weaned from mechanical ventilation and has done well without recurrence. To our knowledge, this is the first reported case of PMX-DHP therapy for severe APT. We speculate that PMX-DHP could be a new treatment strategy for severe APT.

A hyperbranched polymer was used as a catalyst stabilizer for use in a direct formic acid fuel cell, DFAFC, to obtain a high performance with a low catalyst loading. The catalyst ink was prepared by the mixing of Pd nanoparticles stabilized by a hyper branched polymer (H-Pd) and carbon black, which was then calcinated at 300 oC and 500 oC in flowing nitrogen to investigate the effect of the stabilizer residual on the catalytic activity for the formic acid oxidation. It was found that the catalytic activity of the H-Pd was 6 times higher than that of Pd black with a 500 oC calcination. In this condition, a cluster of Pd nanoparticles was observed. By using this catalyst as an anode catalyst of the DFAFC, a 6 times higher power density could be obtained compared to the case using Pd black.

Background: Pulmonary emphysema is characterized by irreversible airflow obstruction, inflammation, oxidative stress imbalance and lung remodeling, resulting in reduced lung function and a lower quality of life. Galectin (Gal)-9 plays a crucial role in the modulation of innate and adaptive immunity. Objectives: To investigate whether Gal-9 reduce pulmonary inflammation and lung remodeling in experimental emphysema mouse model. Methods: Emphysema was induced in C57BL/6 mice by intratracheal administration of porcine pancreatic elastase (PPE) (2 IU) once on day 0. Gal-9 (3 µg/body) or PBS was administered subcutaneously, once daily from day -1 to day 5. Results: Gal-9 suppressed pathological changes of emphysema induced by PPE. The mean linear intercept length (Lm) of Gal-9-treated emphysema mice was lower than that of PBS-treated emphysema mice (66.1 ± 3.3 µm vs. 118.8 ± 14.8 µm, respectively, P Conclusion: Subcutaneous administration of Gal-9 decreases the severity of elastase-induced inflammation and airspace enlargement by inhibiting the chemotaxis of neutrophils and decreasing MMP-9. These results indicate that Gal-9 may be an effective therapeutic agent for the treatment of emphysema and COPD.

The progression of coronary atherosclerosis has been influenced by the presence of chronic kidney disease (CKD). This study investigated the impact of CKD stages on coronary plaque components observed on optical coherence tomography (OCT). We investigated 296 native coronary lesions with stable angina pectoris treated with stent implantation. All lesions were divided into the three groups according to the values of estimated glomerular filtration rate (eGFR, mL min-1 1.73 m-2): the non-CKD group (eGFR ≥60, n = 142), CKD group (15 ≤ eGFR

Nonlinear performance of 8QAM-alternative modulation formats are compared to evaluate the BICM capacity. Simulation results show that the recently proposed 4D-2A8PSK, optimized DP-Circular-8QAM, and 64SP-12QAM all have at least 0.7 dB margins than DP-Star-8QAM.

We propose an enhancement to the fast blind CD estimation method based on auto-correlation of signal power. The use of Hartley and Cosine transform allow 30% and 70% complexity reductions, within a maximum loss of 2% in accuracy.

We introduce a new geometric shaping to optimize signal constellations maximizing generalized mutual information for both binary and nonbinary coding. With parametric projection of hyper cubes, we can perform seamless constellation shaping with near 1 dB gain.

We report designs of compact and efficient waveguide taper structures for InP output couplers based on transformation optics. Air holes patterned on the taper can achieve over 10% increase in coupling efficiency.

Low code rate DP-8PSK was studied as an alternative to DP-QPSK for long distance coherent communications. For 4,000 km transmission with multiple link configurations, low code rate DP-8PSK is shown to have 1.6–1.8 dB span loss budget over DP-QPSK for the same spectral efficiency through simulations.

The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matters. Among atmospheric particulate matters, the PAHs concentration was highest in FPM collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric particulate matters. 1/EC50 was 1-10 L g-1 PM for atmospheric particulate matters and 0.1-1 L g-1 dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg-1 16PAHs) and was the same in the order of the magnitude as that of FPM and CPM. The ratio of sediments collected from the west was more similar to that of CPM while that of the east was to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and from the results. PAHs pattern of sea sediments was fairly different from that of FPM and CPM. Comparison to previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources., This work was supported by Kurita Water and Environmental Foundation and Grant-in-Aid for Scientific Research (C)

常時微動のアレイ観測による位相速度に基づいて，福井平野周辺の第三紀基盤岩までのS波速度構造モデルの算出を試みた．はじめに，アレイ観測にSPAC法を適用して求められたRayleigh波位相速度をターゲットとする逆解析により，アレイ観測地点のS波速度構造を求めた．次いで，アレイ観測地点の最適S波速度構造をサンプルとした空間補間を行い，福井平野の約500mメッシュのS波速度構造モデルを求めた．さらに，1点3成分観測を高密度で行い，H/Vスペクトルから判読された卓越周期を補助データとし，アレイ観測点のS波速度構造と卓越周期の相関を利用したコクリギングを行い，S波速度構造の高精度化を図った．推定された地盤構造は，弾性波探査，重力異常に基づく密度構造などと調和的であり一定の信頼性を有することを確認した．

We present a statistical inference based multi-pilot aided CPE algorithm and analyze its performance via simulations. We experimentally verify LDPC coded back-to-back performance using 10 GBd DP-64QAM and DP-256QAM modulation, with transmitter and receiver linewidths of 100 kHz.

We describe the design of a trained and pilot-aided digital coherent receiver, capable of detecting a 1 Tb/s superchannel with a single optical front-end. Algorithms for receiver training are described, which calculate the equalizer coefficients, subchannel SNRs, and centroids of the transmitted constellations. Algorithms for pilot-aided operation are then described in detail, providing pilot-aided constant modulus equalization and joint carrier phase estimation over several coherent subchannels. We demonstrate detection of a superchannel with net bit rate in excess of 1 Tb/s with a single coherent receiver. An 1110 GBd DP-64QAM Nyquist superchannel is used, with 1.32 Tb/s gross bit rate.

Introduction: High serum levels of lipoprotein (a) (Lp(a)) are associated with adverse outcomes after acute myocardial infarction (AMI). Lp(a) exerts its atherogenic and thrombogenic properties, which suggests greater lipid component of plaque and thrombi at the culprit lesion of AMI with elevated Lp(a). The risk of coronary artery disease is increased with a threshold serum Lp(a) level of 25 mg/dl. Purpose: We sought to evaluate impact of Lp(a) on myocardial viability and left ventricular function after AMI. Methods: The study included 156 patients (66±10.7 yrs, mean±sd, men 122, LAD/LCX/RCA 80/16/60) with first AMI within 24 hours from the onset who underwent emergent PCI. Serum Lp(a) was measured at admission. Serum CPK values were measured at admission and at intervals of 4 hours. Peak CPK value was determined. Within 2 weeks, Tl/BMIPP SPECT was performed to measure perfusion-metabolism mismatch score, an indicator of viable myocardium, from each total defect score of Tl/BMIPP using 17-segment model and semiquantitative visual score (0:normal, to 4:no uptake). Left ventricular ejection fraction (LVEF) was measured by two-dimensional echocardiography (2D trace) within 1 week (baseline LVEF) and at 6 months to 1 year (follow-up LVEF). Results: The study patients were divided into the group with serum Lp(a)≧25mg/dl at admission (n=42, Lp(a) 44.0±19.4mg/dl) and the group with Lp(a) Conclusions: Elevated Lp(a) was associated with less myocardial viability and less LVEF recovery after AMI.

Background: Residual risk of cardiovascular disease exists even in patients achieving low-density lipoprotein cholesterol (LDL-C) goals. A low value of serum eicosapentaenoic acid to arachidonic acid (EPA/AA) ratio is well known to be associated with cardiovascular events. However, the association between serum EPA/AA ratio and coronary plaque components has not been fully investigated. Purpose: We evaluated the relationships between serum EPA/AA ratio and coronary plaque morphology on iMap-intravascular ultrasound (IVUS) which is a 40 MHz IVUS tissue characteristic system. Methods: We investigated 80 consecutive coronary culprit lesions with stable angina pectoris (SAP) patients, who underwent pre-intervention iMap-IVUS. All patients were divided into two groups; groups with higher values of the median EPA/AA ratio and lower values of the median EPA/AA ratio. We assessed the relationship between the two groups. Results: Median values of EPA, AA and EPA/AA ratio were 67.5 (44.3-100.3) μg/ml, 174.2 (145.5-202.9) μg/ml, and 0.38 (0.23-0.60). Patients in lower EPA/AA ratio group ( In lower LDL-C group (42.1%), cut-off value of EPA/AA ratio was 0.20 (sensitivity 50%, specificity 94%, area under the curve 0.77, p=0.02). Conclusion: serum EPA/AA ratio may be related to plaque components at the culprit site in SAP patients with low LDL-C values.

Stable nitrogen and oxygen isotope ratios of nitrate (δ(15)N-NO(3) and δ(18)O-NO(3)) have recently been used to identify nitrogen sources in water environments. However, there have been no investigations designed to determine nitrate isotopes in non-point sources in urban areas for evaluating the impact of surface deposits on nitrogen in surface runoff. In this study, we collected rainwater, surface runoff and surface deposits (road dust, roof dust and soil) to evaluate the nitrogen sources in surface runoff using nitrate isotopes. There were no large differences in δ(15)N-NO(3) among rainwater (-0.3‰ to 1.5‰), surface runoff (-2.7‰ to 0.4‰), leachates from road dust (-5.8‰ to 6.2‰) and soil (-11.5‰ to 0.6‰). In contrast, the δ(18)O-NO(3) in surface runoff (28.5-47.9‰) was lower than that in rainwater (62.7-78.6‰), and higher than that in leachates from road dust (6.1-27.6‰) and soil (-1.1‰ to 6.6‰). δ(18)O-NO(3) is a useful indicator for evaluating the NO(3)-N sources in surface runoff. Using this indicator, NO(3)-N from road dust was estimated to account for more than half of the NO(3)-N in surface runoff. This is consistent with a result based on a comparison of their loads per unit surface between rainwater and surface runoff, which also showed that most of the nitrogen in surface runoff was derived from surface deposits.

Galectin (Gal)-9 plays a crucial role in the modulation of innate and adaptive immunity.To investigate whether Gal-9 plays a role in a murine acute lung injury (ALI) model.C57BL/6 mice were pretreated with Gal-9 by subcutaneous injection 24 and 48 hours before intranasal LPS inoculation.Gal-9 suppressed pathological changes of ALI induced by LPS. Gal-9 reduced levels of proinflammatory cytokines and chemokines, such as tumor necrosis factor (TNF)-α, IL-1β, IL-6, and keratinocyte-derived cytokine; decreased neutrophils; and increased IL-10 and CD11b(+)Gr-1(+) macrophages in the bronchoalveolar lavage fluid of ALI mice. In Gal-9-deficient mice, pathological changes of ALI were exaggerated, and the number of neutrophils and the TNF-α level were increased. CD11b(+)Gr-1(+) cells were increased in the spleen of both Gal-9-treated and phosphate-buffered saline (PBS)-treated ALI mice, but only Gal-9 increased the ability of CCR2-expressing macrophages to migrate toward monocyte chemoattractant protein-1. Transfer of CD11b(+)Gr-1(+) macrophages obtained from Gal-9-treated mice ameliorated ALI. CD11b(+)Gr-1(+) macrophages obtained from Gal-9-treated but not PBS-treated mice suppressed TNF-α and keratinocyte-derived cytokine production from LPS-stimulated macrophages, and down-regulated Toll-like receptor-4 (TLR4) and TLR2 expression on thioglycollate-elicited macrophages. Fluorescence-activated cell-sorting analysis revealed that CD14 is negligible on CD11b(+)Gr-1(+) macrophages obtained from Gal-9-treated mice, although those from both groups resembled plasmacytoid dendritic cells (pDCs). Gal-9 down-regulated CD14 on pDC-like macrophages from PBS-treated mice independently of Gal-9/Tim-3 (T-cell immunoglobulin- and mucin domain-containing molecule-3) interaction, resulting in the acquisition of suppressive function, suggesting that the loss of CD14 by Gal-9 is critical for the suppression of pDC-like macrophages.Gal-9 attenuates ALI by expanding CD14(-)CD11b(+)Gr-1(+) pDC-like macrophages by preferentially suppressing macrophage functions to release proinflammatory cytokines through TLR4 and TLR2 down-regulation.

Platinum nanoparticles dispersed in the ammonium salts of hyperbranched polystyrene, Pt@HPS-NR3Cl, catalyzed the hydrogenation of ketones and aldehydes when water was used as the solvent without an...

Atherosclerotic change of aortic valve (AoV) is one of the crucial causes of serious heart disease. However, its detailed in-vivo observation has not been possible due to imaging limitations of computed tomography or transesophageal echocardiography. Non-obstructive aortic angioscopy (AAS) is a

TiC−Fe system cermets and TiC−SUS310L (TiC−SS) system cermets with fully relative density have been produced from elemental powders via self-propagating high-temperature synthesis (SHS) reaction combined with pseudo-hot isostatic pressing. X-ray diffraction (XRD) analysis showed that the SHS products consist of TiC and the binder phase of Fe or SS. Metallographic analysis revealed TiC particles of several micrometer size were homogeneously dispersed in the binder phase. Regardless of differences in the binders, both cermets have similar tendencies: their relative densities increased and their hardness and compressive strengths decreased with increases in the volume fraction of either Fe or SS. In addition, the cermets used stainless steel as the binder had twice superior corrosion resistance to those used iron and also their hardness and compressive strength showed excellent values.

When powder mixtures of iron, aluminum, titanium and boron were heated under pseudo hot isostatic pressure in vacuum to a temperature just above the melting point of aluminum, sudden and rapid temperature rise was always observed, which was due to the exothermic reactions producing FeAl and TiB 2 . Metallographic investigations revealed that the products consisted of homogeneously dispersed fine hexagonal TiB 2 particles and FeAl matrix and that the products included some pores. As the concentrations of titanium and boron in the powder mixture increased, the TiB 2 particle size and porosity increased. Both the particle size and the porosity were dramatically reduced by preheating of the powder mixture, which brought about increase in Vickers hardness of the reaction products.

In the present study, it is shown that TiC–20vol%Fe composites can be successfully fabricated by combustion synthesis from elemental powder compacts of titanium, carbon and iron. Particular concern is directed to reduction of the porosity in the product by preheating procedure of the powder compact. There exists 36% of porosity in the fabricated composites without the preheating treatment. However, the preheating treatment leads to the reduction of the volume fraction of porosity to about 10% and, furthermore, a two-step preheating treatment reduces the volume fraction of porosity down to about 5%. Vickers hardness of the TiC–Fe composites fabricated in this study was measured to be around 1300 HV regardless of the preheating condition.