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A unique charge/discharge mechanism of amorphous TiS4 is reported. Amorphous transition metal polysulfide electrodes exhibit anomalous charge/discharge performance and should have a unique charge/discharge mechanism: neither the typical intercalation/deintercalation mechanism nor the conversion-type one, but a mixture of the two. Analyzing the mechanism of such electrodes has been a challenge because fewer tools are available to examine the "amorphous" structure. It is revealed that the electrode undergoes two distinct structural changes: (i) the deformation and formation of S-S disulfide bonds and (ii) changes in the coordination number of titanium. These structural changes proceed continuously and concertedly for Li insertion/extraction. The results of this study provide a novel and unique model of amorphous electrode materials with significantly larger capacities.
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We report on a tunable intense femtosecond mid-infrared (mid-IR) light source carrying orbital angular momentum (OAM). Our setup is based on an optical parametric amplification system with an 800 nm pump shaped with a spiral phase plate. We confirm the anisotropic OAM transfer from the pump to the idler through stimulated difference frequency generation by measuring the diffraction patterns of a triangular aperture illuminated by the signal, pump, and idler beams. The tunability of the setup is demonstrated by performing measurements at 3.0 and 3.6 µm idler wavelengths. This result provides a robust method of controlling OAM in strong field physics and designing secondary sources carrying OAM in the extreme ultraviolet spectral range through high-order harmonics generation.
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Nanometric rods of hydroxyapatite (HA) were aligned in selective crystallographic directions by the alternation of adsorbing molecules. The side and end faces of HA nanorods elongated in the c direction were covered with oleic acid (OA) and tetraoctylammonium (TOA) ions, respectively. Alignment in the c direction of the OA-modified nanorods was produced through epitaxial attachment of the bare end faces in toluene because the side faces were hydrophobized with the negatively charged modifier. Another alignment-in the a direction of the TOA-modified HA nanorods-was obtained through the epitaxial attachment of the bare side faces in ethanol due to stabilization of the end faces with the positively charged modifier. Controlled alignments of the nanorods in the a and c directions were achieved through oriented attachment with the selective coverage of the c and a faces with the specific modifiers.
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Monocrystalline architectures with well-defined shapes were achieved by bottom-up routes through epitaxial attachment of Mn3O4 nanocrystals. The crystallographically continuous 1D chains elongated in the a axis and 2D panels having large a or c faces were obtained by removal of the organic mediator from surfactant-mediated 1D and 2D arrays of Mn3O4 nanocrystals, respectively. Our basal approach indicates that the epitaxial attachment through the surfactant-mediated arrays is utilized for fabrication of a wide variety of micrometric architectures from nanometric crystalline units.
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Micrometric linear chains (1D arrays), monolayers (2D arrays), and superstructures (3D arrays) of anisotropic Mn3O4 nanocuboids were selectively produced by oriented self-assembly through evaporation of a dispersion. The 1D arrays were basically formed on a substrate via oriented self-assembly of the rectangular crystals in the ⟨100⟩ direction. The 2D and 3D microarrays were obtained by adjusting the particle concentration of the dispersion. The [001] direction of tetragonal crystal was controlled to be parallel and perpendicular to the substrate by changing the polarity of the medium.
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Nano-submicron particles of sub-stoichiometric titanium oxide (TiOx) were synthesized by irradiation of TiO(2) particles dispersed in liquid with a Nd:YAG pulsed UV laser, and their physicochemical and electrochemical properties were examined. After laser irradiation for 1 h, spherical oxide particles of up to ca. 300 nm in diameter were formed regardless of the liquid used, however the reduction of TiO(2) largely depended on the liquid: acetonitrile most strongly promoted the reduction of TiO(2) by UV laser irradiation. The mean valence of titanium in TiOx synthesized in acetonitrile was ca. 3.5, which is comparable to that of the most-reduced Magnéli phase, Ti(4)O(7). While the electrical conductivity of as-washed TiOx was significantly low, annealing at 900 degrees C in hydrogen dramatically improved conductivity. The oxidation resistance of TiOx was examined by cyclic voltammetry to a high potential (1.5 V) using a MEA under PEMFC operating conditions. TiOx showed a much lower anodic corrosion current at >1.0 V than XC-72R carbon, which suggests that TiOx may exhibit superior oxidation resistance as a catalyst support material at high potentials.
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Nanometer-scale switching of the crystallographic orientation enables production of novel superlattices for exploration of new functions. Elaborate multilayered architectures of Mn3O4 nanocuboids were constructed by a convective self-assembly process. The nanometric cuboids were accumulated into orientation-switched superlattices on micrometric scales by controlling the a and c directions of the tetragonal crystal periodically. The orthogonal stacking of the tetragonal nanoblocks was achieved through the layer-by-layer manipulation process of two types of 2D arrays with different orientations.
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To confirm the previous reports demonstrating the difference in the octanol extraction fractions between the currently available two N-isopropyl-4-iodoamphetamine (123I) products (IMP(A) and IMP(B)), we newly developed the standard input function for IMP(B) in 19 healthy volunteers and compared it with the established standard input function, which has been originally generated with IMP(A). The octanol extraction fractions of IMP(B) were stable from 5 minutes to 16 minutes post injection and significantly higher than those of IMP(A). The mCBFs calculated with IMP(B) by using the established standard input function for IMP(A) tended to be higher than those with the combination of IMP(A) and the established standard input function though the difference was not significant. When measured with IMP(B) combined with the correspondent standard input function, mCBFs were identical to those calculated with IMP(A) with the established standard input function, suggesting that the appropriate standard input function should be used according to the product used.
Assuntos
Radioisótopos do Iodo/normas , Iofetamina/normas , Compostos Radiofarmacêuticos/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
We evaluated the relationship between regional cerebral blood flow (rCBF) and clinical symptoms in patients with schizophrenia. Single photon emission computed tomography with N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) was used to study 29 patients with schizophrenia. Clinical symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). We examined the correlation between rCBF and each BPRS item score using Statistical Parametric Mapping software. Corrected P-values < 0.05 were considered as statistically significant. The suspiciousness score on the BPRS was positively correlated with rCBF in the left inferior temporal gyrus. There was no significant correlation between rCBF and any other items of the BPRS. There was no significant correlation between rCBF and chlorpromazine-equivalent dosage. This analysis permits the quantitative assessment of the severity of persecutory delusions in relation to left temporal perfusion in patients with schizophrenia.
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Escalas de Graduação Psiquiátrica Breve , Lateralidade Funcional/fisiologia , Transtornos da Personalidade/diagnóstico , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatologia , Psicologia do Esquizofrênico , Lobo Temporal/irrigação sanguínea , Lobo Temporal/fisiopatologia , Adolescente , Adulto , Circulação Cerebrovascular/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos da Personalidade/etiologia , Esquizofrenia/complicações , Índice de Gravidade de Doença , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Tetragonal Mn3O4 nanocuboids were aligned in selective crystallographic directions by molecularly mediated manipulation. Alignment in the a direction was produced by a face-by-a face assembly of hydrophobic nanocuboids covered with oleic acid. Another 1D array in the c direction was obtained through c face-to-c face assembly with the replacement of the organic modifiers.
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Anatase TiO2 nanocrystals were crystallographically connected through UV-induced epitaxial attachments in 1D and 2D arrays with photocatalytic decomposition of the organic mediator.
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Orientation-controlled 2D and 3D microarrays of Mn3O4 nanocuboids that were mediated by a conductive polymer were fabricated by evaporation-induced self-assembly of the oxide nanoblocks and subsequent polymerization of pyrrole in the interparticle spaces. Free-standing mesoporous polypyrroles (PPy) having chain- and square-grid-like nanovoid arrays were obtained as replicas of the composite assemblies by dissolving the oxide nanoblocks. The PPy-mediated manganese oxide arrays exhibited stable electrochemical performance as an ultrathin anode of a lithium-ion secondary battery.
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The asymmetric amide anion (CF3SO2-N(-)-COCF3) has excellent abilities to lower both the melting points and viscosities of room temperature ionic liquids (RTILs) combining with small aliphatic ammonium cations that have not yet been reported to form RTILs.
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Íons/química , Solventes/química , Amidas/química , Química Orgânica/métodos , Poluição Ambiental/prevenção & controle , Compostos de Amônio Quaternário/química , Sais/química , TemperaturaRESUMO
PURPOSE: Traumatic brain injury (TBI) causes brain dysfunction in many patients. However, some patients have severe brain dysfunction but display no abnormalities on magnetic resonance imaging (MRI). There have been some reports of hypometabolism even in such patients. The purpose of this study was to investigate the relationship between metabolic abnormality and loss of neuronal integrity in TBI patients with some symptoms but without MRI abnormalities. METHODS: The study population comprised ten patients with TBI and ten normal volunteers. All of the patients were examined at least 1 year after the injury. ( 15)O-labelled gas PET and [(11)C]flumazenil (FMZ) positron emission tomography (PET) were carried out. The cerebral metabolic rate of oxygen (CMRO(2)) and binding potential (BP) images of FMZ were calculated. Axial T2WI, T2*WI and FLAIR images were obtained. Coronal images were added in some cases. RESULTS: All of the patients had normal MRI findings, and all showed areas with abnormally low CMRO(2). Low uptake on BP images was observed in six patients (60%). No lesions that showed low uptake on BP images were without low CMRO(2). On the other hand, there were 14 lesions with low CMRO(2) but without BP abnormalities. CONCLUSION: These results indicate that there are metabolic abnormalities in TBI patients with some symptoms after brain injury but without abnormalities on MRI. Some of the hypometabolic lesions showed low BP, indicating a loss of neuronal integrity. Thus, FMZ PET may have potential to distinguish hypometabolism caused by neuronal loss from that caused by other factors.
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Encefalopatias Metabólicas/diagnóstico por imagem , Encefalopatias Metabólicas/patologia , Lesões Encefálicas/diagnóstico por imagem , Lesões Encefálicas/patologia , Imageamento por Ressonância Magnética/métodos , Neurônios/diagnóstico por imagem , Neurônios/patologia , Adulto , Idoso , Reações Falso-Positivas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cintilografia , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
PURPOSE: Long-chain fatty acid (LCFA) is the main energy source for normal myocardium at rest, but in ischemic myocardium, the main energy substrate shifts from LCFA to glucose. 123I-BMIPP is a radiolabeled LCFA analog. In chronic stable angina without previous infarction, we suppose that reduced 123I-BMIPP uptake is related to the substrate shift in myocardium with decreased myocardial flow reserve (MFR). The purpose of this study was to relate 123I-BMIPP uptake to rest myocardial blood flow (MBF), hyperemic MBF, and MFR assessed with 15O-water positron emission tomography (PET). METHODS: We enrolled 21 patients with chronic stable angina without previous infarction, all of whom underwent 123I-BMIPP single-photon emission computed tomography (SPECT) and 15O-water PET. The left ventricle was divided into 13 segments. In each segment, rest MBF and hyperemic MBF were measured by PET. 123I-BMIPP uptake was evaluated as follows: score 0=normal, 1=slightly decreased uptake, 2=moderately decreased uptake, 3=severely decreased uptake, and 4=complete defect. 123I-BMIPP uptake was compared with rest MBF, hyperemic MBF, and MFR. RESULTS: The numbers of segments with 123I-BMIPP scores 0, 1, 2, 3, and 4 were 178, 40, 25, 24, and 0, respectively. The rest MBFs for scores 0, 1, 2, and 3 were 0.93+/-0.25, 0.86+/-0.21, 0.97+/-0.30, and 0.99+/-0.37 ml/min/g, respectively. The hyperemic MBFs for scores 0, 1, 2, and 3 were 2.76+/-1.29, 1.84+/-0.74, 1.37+/-0.39, and 1.08+/-0.40 ml/min/g, respectively. The MFRs for scores 0, 1, 2, and 3 were 3.01+/-1.38, 2.20+/-0.95, 1.44+/-0.22, and 1.10+/-0.26, respectively. As 123I-BMIPP uptake declined, hyperemic MBF and MFR decreased. CONCLUSION: In chronic stable angina without previous infarction, reduced 123I-BMIPP uptake implies decreased MFR.
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Angina Instável/diagnóstico por imagem , Angina Instável/metabolismo , Doença da Artéria Coronariana/diagnóstico por imagem , Ácidos Graxos/metabolismo , Iodobenzenos/farmacocinética , Adulto , Idoso , Angina Instável/etiologia , Doença da Artéria Coronariana/complicações , Doença da Artéria Coronariana/metabolismo , Circulação Coronária , Ácidos Graxos/farmacocinética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radioisótopos de Oxigênio/farmacocinética , Cintilografia , Compostos Radiofarmacêuticos/farmacocinética , Medição de Risco/métodos , Fatores de RiscoRESUMO
PURPOSE: Myocardial glucose utilization (MGU) is altered in various heart diseases. The aim of this study was to quantitatively assess regional myocardial glucose utilization in patients with left ventricular (LV) dysfunction by dynamic( 18)F-fluorodeoxyglucose positron emission tomography (FDG PET). METHODS: A total of 18 subjects were studied, including ten with LV dysfunction (seven with idiopathic dilated cardiomyopathy and three with aortic regurgitation; NYHA II in 8 and III in 2) and eight healthy normal volunteers. Patients with diabetes mellitus were excluded. A dynamic PET study was performed for 40 min following the injection of 370 MBq of FDG after 50-g glucose loading. On the basis of a three-compartment model, MGU, K1, k2, and k3 were computed on a pixel by pixel basis to generate LV myocardial parametric maps. FDG standardized uptake value (SUV) was also calculated using static images obtained 40 min after FDG injection. These metabolic values were compared with myocardial flow distribution (%Flow), LVEF, LV volumes, and LV wall thickening (WT) determined by gated myocardial single-photon emission computed tomography using QGS software in eight myocardial segments. RESULTS: MGU correlated positively with LV volumes and negatively with LVEF. K(1) was significantly higher in the segments of the patients than in those of the normal volunteers (0.082+/-0.055 vs 0.041+/-0.017 ml min(-1) g(-1), p<0.05), although there was no difference in MGU between the groups. On the other hand, SUV, k2, and k3 did not differ significantly between the groups. Among the patients, the K1 values were significantly higher in the areas with impaired WT (%WT<17%) (0.109+/-0.063 vs 0.069+/-0.062 ml min(-1) g(-1), p<0.05) and in the areas with flow reduction (%Flow<71%) (0.112+/-0.076 vs 0.071+/-0.046 ml min(-1) g(-1), p<0.05). CONCLUSION: These results indicate that glucose utilization was preserved in the patients with LV dysfunction, mainly due to an increase in glucose transport, particularly in the regions with severely impaired LV function. Thus, the quantitative assessment of myocardial glucose utilization by FDG dynamic PET may provide useful information for assessing the regional myocardial metabolic status in patients with LV dysfunction.