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AbstractHeat-resistant in-vessel components, i.e., a heat sink, a front-end optics housing, and a diagnostic window have been designed in terms of heat-handling capability and thermal stress and mechanical stress by using a finite element method code. The heat sink, which is exposed to a plasma heat flux of up to 0.3 MW/m2, consists of carbon tiles, a carbon sheet, and a stainless steel heat sink with a water-cooling channel. Analysis shows that at a water flow rate of 0.9 kg/s with a water pressure of 0.5 MPa, an increase in the carbon tile temperature is mitigated below the limit related with detrimental red-hot (900°C). The front-end optics housing temperature and the diagnostic window of sapphire glass temperature are within the allowable temperature. The thermal stress and mechanical stress are less than the allowable value, respectively.

The M component and TNM stage groupings for malignant pleural mesothelioma (MPM) have been empirical. The International Association for the Study of Lung Cancer developed a multinational database to propose evidence-based revisions for the eighth edition of the TNM classification of MPM.

The current T component for malignant pleural mesothelioma (MPM) has been predominantly informed by surgical data sets and consensus. The International Association for the Study of Lung Cancer undertook revision of the seventh edition of the staging system for MPM with the goal of developing recommendations for the eighth edition.

For nearly 40 years, there was no generally accepted staging system for malignant pleural mesothelioma. In 1994, members of the International Mesothelioma Interest Group, in collaboration with the International Association for the Study of Lung Cancer, proposed a TNM staging system based on analyses of outcomes in retrospective surgical series and small clinical trials. Subsequently accepted by the American Joint Commission on Cancer and the Union for International Cancer Control for the sixth editions of their staging manuals, this system has since been the international staging standard. However, it has significant limitations, particularly with respect to clinical staging and to the categories for lymph node staging. Here we provide an overview of the development of the International Association for the Study of Lung Cancer malignant pleural mesothelioma staging database, which was designed to address these limitations through the development of a large international data set. Analyses of this database, described in papers linked to this overview, are being used to inform revisions in the eighth editions of the American Joint Commission on Cancer and Union for International Cancer Control staging systems.

AbstractThe research plan of the JT-60SA, a superconducting tokamak device currently under construction, requests a powerful pellet injection system for its particle fueling and edge-localized-mode (ELM) pacing experiments. These investigations, foreseen to answer basic questions with respect to the operation of ITER and a future fusion power plant like DEMO, need pellets with flexible parameters delivered precisely and reliably for control purposes. Here, we present a conceptual design of this system based on classical pellet technology. Analysis showed pellets will show the best performance for fueling and most likely also for ELM pacing when injected from the torus inboard side, despite the limited maximum pellet speed caused by this approach. This is due to constructional constraints rising from the fact the JT-60SA vacuum vessel is already under construction, enforcing inboard injection via a multibend guiding-tube system and limiting the maximum pellet speed to about 470 m/s. To match this boundary condition and fulfill the need for precise control, a centrifuge accelerator has been chosen. Based on the stop cylinder principle and equipped with a double accelerator arm, it can host up to six steady-state ice extruders working simultaneously for pellet production. This way, all system requirements expressed in the research plan can be well covered, providing even some headroom for better flexibility during the planned investigations. Details of our design and the reasoning for the layout chosen are provided in this paper.

Mps One Binder Kinase Activator (MOB)1A/1B are core components of the Hippo pathway. These proteins, which coactivate LArge Tumour Suppressor homologue kinases, are also tumour suppressors. To investigate MOB1A/B’s roles in normal physiology and lung cancer, we generated doxycycline (Dox)-inducible, bronchioalveolar epithelium-specific, null mutations of MOB1A/Bin mice (SPC-rtTA/(tetO)7-Cre/Mob1aflox/flox/Mob1b−/−; termed luMob1DKOmice). Most mutants (70%) receiving Dox in utero(luMob1DKO (E6.5-18.5)mice) died of hypoxia within 1 h post-birth. Their alveolar epithelial cells showed increased proliferation, impaired YAP1/TAZ-dependent differentiation and decreased surfactant protein production, all features characteristic of human respiratory distress syndrome. Intriguingly, mutant mice that received Dox postnatally (luMob1DKO(P21–41) mice) did not develop spontaneous lung adenocarcinomas, and urethane treatment-induced lung tumour formation was decreased (rather than increased). Lungs of luMob1DKO(P21–41) mice exhibited increased detachment of bronchiolar epithelial cells and decreased numbers of the bronchioalveolar stem cells thought to initiate lung adenocarcinomas. YAP1/TAZ-NKX2.1-dependent expression of collagen XVII, a key hemidesmosome component, was also reduced. Thus, a MOB1-YAP1/TAZ-NKX2.1 axis is essential for normal lung homeostasis and expression of the collagen XVII protein necessary for alveolar stem cell maintenance in the lung niche.

Malignant mesothelioma is an aggressive tumor arising from the mesothelial cells of serous membranes and is associated with tumor angiogenesis, which is a prerequisite for tumor progression. Vascular endothelial growth factors (VEGFs) including VEGF-A have a crucial role in tumor angiogenesis. However, bevacizumab, a monoclonal antibody to VEGF-A, has recently been reported not to improve the progression-free survival of patients with malignant mesothelioma. Cell culture supernatant contains extracellular components such as serum, which can mask the existence of unknown cell-derived factors in the supernatant and make it difficult to detect the factors by subsequent protein analysis. We tried using serum-free culture for human mesothelioma cell lines, NCI-H28, NCI-H2452 and NCI-H2052, and only NCI-H2052 cells adapted to serum-free culture. We found that serum-free culture supernatant derived from NCI-H2052 cells induces the formation of capillary-like tube structures (tube formation) in three-dimensional culture, in which endothelial cells sandwiched between two layers of collagen or embedded in collagen are incubated with various angiogenic inducers. However, neither neutralization of VEGF-A nor RNA interference of VEGF receptor 2 (VEGFR2) suppressed the supernatant-induced tube formation. Using mass spectrometry, we identified a total of 399 proteins in the supernatant, among which interleukin-8 (IL-8), growth-regulated α-protein, midkine, IL-18, IL-6, hepatoma-derived growth factor, clusterin and granulin (GRN), also known as progranulin (PGRN), were included as a candidate protein inducing angiogenesis. Neutralizing assays and RNA interference showed that PGRN, but not the above seven candidate proteins, caused the supernatant-induced tube formation. We also found that NCI-H28 and NCI-H2452 cells express PGRN. Furthermore, we demonstrate that not only PGRN but also GRN-like protein have an important role in the supernatant-induced tube formation. Thus, mesothelioma-derived GRNs induce VEGF-independent angiogenesis.

A micro-tomographic System developed at BL47XU in SPring-8 (SP-μCT 47XU) was used to obtain three-dimensional structures of synthetic and natural substances for a test study. Al2O3-YAG cutectic composites, synthetic quartzites (SiO2) and Antarctic micro-meteorites (AMMs) were successfully imaged with the spatial resolution of 1 μm three-dimensionally. Three-dimensional elemental distribution was also obtained using X-ray adsorption edge of Fe in the measurement of an AMM.

Global ship-based programs, with highly accurate, full water column physical and biogeochemical observations repeated decadally since the 1970s, provide a crucial resource for documenting ocean change. The ocean, a central component of Earth's climate system, is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the abyssal ocean beneath 2,000 m, dominated by Southern Ocean warming. The ocean also has taken up about 27% of anthropogenic carbon, resulting in acidification of the upper ocean. Increased stratification has resulted in a decline in oxygen and increase in nutrients in the Northern Hemisphere thermocline and an expansion of tropical oxygen minimum zones. Southern Hemisphere thermocline oxygen increased in the 2000s owing to stronger wind forcing and ventilation. The most recent decade of global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization. Ship-based measurements also show that vertical diffusivity increases from a minimum in the thermocline to a maximum within the bottom 1,500 m, shifting our physical paradigm of the ocean's overturning circulation.

The OPERA experiment was designed to study νμ→ντoscillations in appearance mode using the CERN to Gran Sasso high energy neutrino beam. From 2008 to 2012, 19505 CNGS neutrino interactions were recorded in the OPERA detector. At the present status of the analysis, 4 ντcandidate events have been observed, establishing the oscillation mechanism in the atmospheric sector with a significance of 4.2 σ. The oscillation analysis will be presented in detail and the candidate events will be described. The final measurement of the atmospheric muon charge ratio in the TeV region will be also reported.

Microthrombosis and reactive inflammation contribute to neuronal injury after subarachnoid hemorrhage (SAH). ADAMTS‐13 cleaves von Willebrand factor multimers, and inhibits thrombus formation and, seemingly, inflammatory reactions.

The Yb-based heavy-fermion compound Yb2Ni12P7with a hexagonal Zr2Fe12P7-type crystal structure was investigated by using the 31P nuclear magnetic resonance (NMR) technique. The complicated NMR line changes its shape gradually with decreasing temperature, implying the presence of some Knight shift components. The temperature dependences of the Knight shift and the nuclear spin-lattice relaxation rate 1/T1suggest the delocalization of 4felectrons.

Retentions of Hydrogen (H) and deuterium (D) in the side surfaces (gaps between tiles) of the carbon tiles used as first wall in JT-60U were measured by the thermal desorption spectroscopy. In the gaps, the H and D retention were dominated in carbon deposited layer. The gap retention was less than that of the eroded plasma facing surface, where the retention was saturated, and linearly increased with exposure time. Overall retention rate in the gaps of the first wall tiles was determined to be 4.0 × 1019H+D/s, and was comparable or larger than those in the re-deposited layers on the plasma facing surfaces and in the shadowed areas in the divertor region.

AbstractT retention and its depth profile in the graphite tiles used for first wall of JT-60U have been measured by a tritium imaging plate technique and a full combustion method. T was found only limited depth beneath the plasma facing surface and little in both the surface region shallow than 1 μm and in bulk more than 1mm in depth. Although most of T produced by DD reactions are thermalized and neutralized in plasma and impinge on the plasma facing surface and penetrate into the inner surface, they are isotopically replaced by subsequently incoming D. Only some of high energy T escaping from plasma are directly implanted beneath the surface and retained escaping from the isotopic replacement until attainment of a saturation concentration.

AbstractAreal mass densities of carbon dust collected in the baffle and divertor regions of JT-60U were investigated. On the plasma-facing surface, large areal density of 610 mg/m2is found at the upper tile of the inner divertor, which is much larger than other areas due to the soft deposition. On the other hand, as for the plasma-shadowed area, largest areal density of 5,100 mg/m2was found underneath the dome structure. The total dust weights at the plasma-facing surface and the shadowed areas were estimated to be 1.3 g and 22.2 g, respectively, assuming the toroidal symmetry. Count-based size distributions were also investigated. The average dust size of the main population is less than 20 μm for both the plasma-facing surface and the shadowed area.

One of the vertical magnetic recordings medium materials of the hard disk drive (HDD) is a Pt-Fe thin film. The development of ultra-high density magnetic recording medium in next generation is expected the magnetic disks such as HDD with capacity enlargement of the data. In order to study effectiveness of the proposed sputtering method, we evaluated micro structure, magnetic and the mechanical properties of a Pt-Fe thin film by some sputtering process conditions. From research results, effect sputtering conditions on micro-structure and mechanical properties of Pt-Fe nano film are verified.

Metal oxide semiconductor field effect transistors (MOSFETs) using SiC on insulator (SiC-OI) substrate with the structure of 3C-SiC (100)/SiO2/Si have been fabricated. SiC-OI substrates with SiC thicknesses of 100 nm and 600 nm are employed as starting materials and aluminum ions are implanted for p-regions or channel regions with a multi-implantation technique. Afterward, to form the source and drain regions, phosphorus ions are implanted. The gate oxide layer is grown in dry thermal oxidation, followed by post-oxidation annealing. Nickel is used as a contact material for the source and drain region, and aluminum is used for the gate material. From Id-Vd characteristics, 600 nm SiC-OI MOSFET is superior to 100 nm SiC-OI MOSFET. It is might that the crystalline quality of surface SiC layers affects the performance of MOSFET. SiC-OI MOSFET is operated successfully for the first time.

Abstract—Three‐dimensional structures and elemental abundances of four impact tracks in silica aerogel keystones of Stardust samples from comet 81P/Wild 2 (bulbous track 67 and carrot‐type tracks 46, 47, and 68) were examined non‐destructively by synchrotron radiation‐based microtomography and X‐ray fluorescence analysis. Track features, such as lengths, volumes and width as a function of track depth, were obtained quantitatively by tomography. A bulbous portion was present near the track entrance even in carrot‐type tracks. Each impact of a cometary dust particle results in the particle disaggregated into small pieces that were widely distributed on the track walls as well as at its terminal. Fe, S, Ca, Ni, and eight minor elements are concentrated in the bulbous portion of track 68 as well as in terminal grains. It was confirmed that bulbous portions and thin tracks were formed by disaggregation of very fine fragile materials and relatively coarse crystalline particles, respectively. The almost constant ratio of whole Fe mass to track volume indicates that the track volume is almost proportional to the impact kinetic energy. The size of the original impactor was estimated from the absolute Fe mass by assuming its Fe content (CI) and bulk density. Relations between the track sizes normalized by the impactor size and impact conditions are roughly consistent with those of previous hypervelocity impact experiments.

Asbestos is well-known for its tumorigenic activity, but its effect on anti-tumor immunity remains unclear. Therefore, we prepared a sub-line of YT-A1 human NK cells exposed to chrysotile B (CB) asbestos (YT-CB5) as an in vitromodel to analyze the effect of asbestos exposure on NK cells, and examined cytotoxicity and expressions of its related molecules. The cytotoxicity of YT-CB5 against K562 cells decreased compared with the original line of YT-A1 (YT-Org). YT-CB5 exhibited significant decreases in expressions of cell surface NKG2D, 2B4 and intracellular granzyme A. YT-CB5 also exhibited a decrease in the 2B4-dependent cytotoxicity. In addition, the degranulations stimulated via cell surface NKG2D and 2B4 also decreased in YT-CB5. Therefore, peripheral blood NK cells in patients with malignant mesothelioma (MM) were examined and compared with healthy volunteers. NK cells in patients with MM also showed decreases in cytotoxicity against K562. Although the expressions of NKG2D and 2B4 did not decrease in NK cells of MM patients, the expression of cell surface NKp46 decreased. To confirm the effect of asbestos exposure on peripheral blood NK cells, PBMCs were cultured under exposure to CB. NK cells in PBMCs exposed to CB in vitroshowed a significant decrease in the expression of NKp46, whereas NK cells in PBMCs exposed to glass wool did not show such a decrease. These results indicate that exposure to asbestos has the potential to impair the cytotoxicity of NK cells and alter the expression of NK cell-activating receptors including NKG2D, 2B4 and NKp46 and intracellular perforin/granzymes.

The measurements of the difference between the thermodynamic temperature Tand the temperature T90based on the International Temperature Scale of 1990 (ITS-90), (T-T90), by using an acoustic gas thermometer (AGT) working on neon gas is reported in this paper. The AGT introduced a one-liter quasi-spherical resonator made of oxygen-free-copper. The thermodynamic temperature was determined relatively from the speed of sound measurements at a desired temperature regarding to those at the triple point of water. At the present stage, the aimed temperature range was the gallium melting point. Based on the obtained measured speed of sound, the thermodynamic temperature Tand the values of (T-T90) were determined, and the associated uncertainties were estimated. The (T-T90) obtained in the present work was found to agree within the estimated uncertainty with the currently reported values that exist in temperature range overlapping with the present work.

Colour patterns of animals' bodies are usually produced by the spatial distribution of pigments with different colours. However, some animals use the spatial variation of colour-producing microstructures. We have studied one distinctive example of such structurally produced colour patterns, the wing of the Madagascan sunset moth, to clarify the physical rules that underlie the colour variation. It is known that the iridescent wing scale of the sunset moth has the alternate air–cuticle multilayer structure that causes optical interference. The microscopic and optical investigations of various parts of the wing have confirmed that the thickness of the cuticle layers within the scale largely varies to produce the colour pattern. However, it varies in very different ways between the dorsal and ventral sides of the hind wing; the thickness gradually varies on the dorsal side from scale to scale, while the abrupt changes are found on the ventral side to form distinctive borders between differently coloured areas. It is also revealed that an unusual coloration mechanism is involved in the green part of the ventral hind wing: the colour is caused by higher order optical interference of the highly non-ideal multilayer structure. The physical mechanism of the colour pattern formation is briefly discussed with the several mathematical models proposed so far.

There was no experimental evidence for the existence of a hadron with a quark configuration other than three quarks or a quark-antiquark pair although QCD does not forbid the existence of other combinations such as or . Since the LEPS at SPring-8 collaboration reported the first evidence for ?+which has a quark configuration of , extensive experimental efforts have been made to confirm the existence of ?+and other pentaquark baryons. In my paper, I will report on the experimental evidence and counter evidence for pentaquark baryons, especially on ?+. I will also present recent results from the LEPS deuterium data and conclude the paper with future prospects.

Atrial fibrillation (AF) and congestive heart failure share several features and often coexist in the same patients; therefore, serial assessment of regional myocardial function is important for patients with AF. However, the clinical assessment of regional myocardial function in AF is unreliable and difficult because of beat-to-beat variation. Recent reports have shown that the ratio of the preceding to the prepreceding R-R interval (RR1/RR2) can be used to assess global left ventricular systolic function. Accordingly, we tested the hypothesis that regional wall motion can be estimated from a single beat based on RR1/RR2 in patients with AF. Peak systolic strain at basal, mid, and apical segments of the septal wall was measured by Doppler tissue imaging from an apical 4-chamber view for 30 seconds in 50 patients with AF (mean ejection fraction 52.1 +/- 15.3%; mean heart rate 76.4 +/- 16.0/min). There was a positive linear relationship between peak strain and RR1/RR2 and RR1, and a negative relationship with RR2, with the correlation of peak strain to RR1/RR2 was better than that in RR1 or RR2. Furthermore, peak strain at RR1/RR2 = 1 was calculated from the linear regression and compared with the average measured value of all recorded cardiac cycles in each patient. In all cases, average peak strain showed a significant positive correlation with RR1/RR2 at each segment (r = 0.99). In conclusion, regional myocardial strain at RR1/RR2 = 1 on the linear regression represents the average value of all recorded cardiac cycles in patients with AF.

To explore the effects of asbestos and silica on the human immune system, an experimental model of low-dose and long-term exposure was established using a human HTLV-1-immortalized polyclonal T cell line, MT-2 (MT-2Org). MT-2 cells were continuously exposed to asbestos at a concentration (10 µg/ml) which does not induce complete cell death during short-term exposure. After acquiring resistance to CB-induced apoptosis (designated MT-2Rst), an immunological comparison was made between the MT-2Org and MT-2Rst lines in terms of T cell receptor-Vß (TcR-Vß) expression. MT-2Rst cells showed excess expression of various TcR-Vß, although TcR-Vß-overpresenting cells were characterized as undergoing apoptosis due to first contact with CB. Patients with asbestos-related diseases (ARD), such as asbestosis and malignant mesothelioma, were compared with silicosis (SIL) patients as a disease control and with healthy donors (HD). SIL and ARD not only differed in their causative materials, silica and asbestos as mineral silicates, but also in terms of complications; autoimmune disorders in SIL and tumors in ARD. ARD patients showed a restricted overpresentation of TcR-Vß without clonal expansion, whereas SIL patients revealed significant overpresentation of TcR-Vß 7.2. These experimental and clinical analyses indicate the superantigenic and dysregulation of autoimmunity-inducing effects of asbestos and silica, respectively.

Modification for long pulse operation up to 65?s with a neutral beam heating power of 12?MW (30?s) has provided an opportunity for studies on plasma-wall interaction on a time scale of tens of seconds. During a long pulse, ELMy H-mode discharge, the net wall-pumping rate, evaluated by a particle balance analysis, gradually decreases, and subsequently, becomes zero in ~20?s after the neutral beam injection starts. This situation is interpreted as 'wall saturation'. Wall saturation is observed in repetitive long pulse discharges. Although the outgas due to the increase in the divertor plate temperature and increase in the static retention with pulses also contribute to the particle balance, the dynamic retention process dominates the particle balance and determines the wall saturation. Under the condition of wall saturation, the plasma density continuously increases due to insufficient divertor-pumping rate. This density rise results in detachment of the outer divertor plasma, followed by an X-point MARFE. Results from the calculation of a 2-dimensional plasma transport code indicate that higher divertor-pumping efficiency by a factor of 1.5 is required to avoid the detachment. Note that no negative effects on impurity behaviour such as carbon bloom, or significant dilution of the core plasma has been observed even in the case of the total input energy reaching 350?MJ.

Unidirectional solidification of Al-In, Cu-Pb and Cu-Pb-Al monotectic alloys was performed under static magnetic fields up to 10T for formation of the regularly aligned-rod structure. mThe imposition of static magnetic fields exceeding 4T suppressed movement of the In liquid droplets at the Al solidifying front and enhanced the engulfment of the In droplets into the front. As a result, the eutectic-like structure was obtained in the Al-10 and 15at%In hypermonotectic alloys. The micro X-ray tomography indicated that the continuous In rods with diameters of 10-20 µm were aligned parallel to each other. In the case of the Cu-Pb and the Cu-Pb-Al alloys, the imposition of static magnetic fields also enhanced the formation of the aligned Pb rods. The electrochemical etching by using a 10% HNO3 solution successfully removed the minor phase, and the porous aluminum and copper with deep pores were fabricated.

Abstract: The characteristics of tonal noise and the variations of flow structure around NACA0018 airfoil in a uniform flow are studied by means of simultaneous measurement of noise and velocity field by particle-image velocimetry to understand the generation mechanism of tonal noise. Measurements are made on the noise characteristics, the phase-averaged velocity field with respect to the noise signal, and the cross-correlation contour of velocity fluctuations and noise signal. These experimental results indicate that the tonal noise is generated from the periodic vortex structure on the pressure surface of the airfoil near the trailing edge of the airfoil. It is found that the vortex structure is highly correlated with the noise signal, which indicates the presence of noise-source distribution on the pressure surface. The vorticity distribution on the pressure surface breaks down near the trailing edge of the airfoil and forms a staggered vortex street in the wake of the airfoil.

Variation of particle absorption at the first wall has been investigated in long-pulse (~30?s) ELMy H-mode discharges on JT-60U. Quantitative analysis of particle balance indicated that particle inventory at the first wall was globally saturated with a time scale of 10-15?s after several long-pulse discharges. To understand mechanisms of the global wall saturation, distribution of a local wall saturation time on the first wall was calculated from the ion and neutral particle fluxes to the first wall evaluated using a Monte-Carlo neutral particle transport code. The local wall saturation time was estimated to be shorter than 1?s at the divertor plates and the divertor dome, ~10 s at the lower half of the baffle plates and ~100?s at the main chamber wall, respectively. This result suggested that the divertor plates, the divertor dome and the lower half of the baffle plates were saturated in a single discharge. On the other hand, the main chamber wall was not saturated in a single discharge. Based on the above result, a model of the global wall saturation was proposed, where dynamic and static inventory regions are defined depending on the wall temperature.

Compatibility of advanced tokamak plasmas with high density and high radiation loss has been investigated in both reversed shear (RS) plasmas and high βp H-mode plasmas with a weak positive shear on JT-60U. In the RS plasmas, the operating regime is extended to high density above the Greenwald density (nGW) with high confinement (HHy2 > 1) and high radiation loss fraction (frad > 0.9) by tailoring the internal transport barriers (ITBs). With a small plasma-wall gap, the radiation loss in the main plasma (inside the magnetic separatrix) reaches 80% of the heating power due to metal impurity accumulation. However, high confinement of HHy2 = 1.2 is sustained even with such a large radiation loss in the main plasma. By neon seeding, the divertor radiation loss is enhanced from 20% to 40% of the total radiation loss. In the high βp H-mode plasmas, high confinement (HHy2 = 0.96) is maintained at high density ( ) with high radiation loss fraction (frad ∼ 1) by utilizing high-field-side pellets and argon (Ar) injection. The high is attributed to the formation of strong density ITB. Strong core-edge parameter linkage for confinement improvement is observed, where the pedestal pressure and the core plasma confinement increase together. The measured radiation profile including contributions from all impurities in the main plasma is peaked, and the central radiation is ascribed to the contribution from Ar accumulated inside the ITB. Impurity transport analyses indicate that the Ar density profile, twice as peaked as the electron density profile, which is the same level as that observed in the high βp H-mode plasma, can yield an acceptable radiation profile even with a peaked density profile in a fusion reactor.

Free-radical polymerization of dibenzofulvene (DBF) was carried out under various conditions. The radical polymerization proceeded exclusively in vinyl fashion without isomerization of the growing radical or aromatic substitution by the initiator fragment. The polymerization was highly conformation-specific (stereospecific), giving a polymer with a π-stacked conformation in which the main-chain C−C bonds are nearly all trans and the side-chain fluorene moieties are stacked on top of each other. The conformation specificity (stereospecificity) of the DBF radical polymerization was almost similar to that in the anionic polymerization although the radical polymerization products appeared to have a small amount of irregular, defective conformation incorporated into the mostly π-stacked chain. The conformation specificity was affected by the initial monomer concentration and reaction temperature. This observation was explained by a proposed mechanism where two types of the growing radicals having different conformations mediate the polymerization. The poly(DBF) obtained by the radical polymerization showed lower fluorescent intensity and higher solubility possibly due to a small amount of conformational defects.