[show abstract][hide abstract] ABSTRACT: Hydrogen could be produced photocatalytically from natural seawater with simple pre-treatments as demonstrated with La2Ti2O7 suspension under ultraviolet light, CdS/TiO2 suspension under visible light, and Fe2O3 film under photoelectrochemical conditions. In all cases, the formation of harmful chlorine gas was not detected. The role of salts in the seawater was elucidated.
Journal of Photochemistry and Photobiology A Chemistry 08/2013; 189(1):141-144. · 2.42 Impact Factor
[show abstract][hide abstract] ABSTRACT: Nanocomposites of two-dimensional (2D) inorganic nanosheets and inorganic nanocrystals are fabricated. Freestanding atomically flat γ-AlOOH nanosheets (thickness <1 nm) are synthesized from a one-pot hydrothermal reaction. The freestanding and binder-free film composed of the γ-AlOOH nanosheets is fabricated by sedimentation. Because they have positive zeta potentials in the pH range below ca. 9.3, the γ-AlOOH nanosheets can function as positively charged 2D inorganic matrices in a broad pH range. By solution phase (pH 7.0) mixing of the γ-AlOOH nanosheets (zeta potential: 30.7 ± 0.8 mV) and inorganic nanocrystals with negative surface charge, including Au nanoparticles, Au nanorods, CdSe quantum dots, CdSe/CdS/ZnS quantum dots and CdSe nanorods, the nanocomposites are self-assembled via electrostatic interactions. Negatively charged inorganic nanostructures with a wide range of chemical compositions, shapes, sizes, surface ligands and adsorbates can be used as building blocks for γ-AlOOH nanocomposites. Adsorption densities of inorganic nanocrystals on the nanocomposites can be controlled by varying concentrations of nanocrystal solutions. Nanocomposite films containing alternating layers of γ-AlOOH and nanocrystals are obtained by a simple drop casting method.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: To investigate spatiotemporal characteristics and functional correlates of evoked oscillations (EOs) at different frequency bands in human visual cortex. METHODS: Flash visual evoked potentials (FVEPs) were recorded from 11 epilepsy patients with intracranial electrodes placed over the occipital and adjacent cortices. Spatiotemporal characteristics of spectral powers and correlation with various visual responses elicited by electrical cortical stimulations were analyzed in the same electrodes. RESULTS: High γ (60-150Hz) EOs were first recorded in the cuneus and lingual gyri around the calcarine sulcus. Low γ (30-60Hz) EOs appeared also in the mesial occipital cortex slightly later and lasted longer than high γ EGOs. In contrast, lower frequency (LF) <30Hz EOs were recorded more diffusely from occipital surfaces with delayed onset and longer duration. High γ EOs were predominantly associated with simple form visual responses, whereas low γ and LF EOs were with intermediate form and LF EOs with complex form responses. CONCLUSIONS: FVEP spectral power analysis directly recorded from human visual cortex showed distinct spatiotemporal distributions in high and low γ, or LF bands that have different functional correlates. SIGNIFICANCE: Phase-locked EOs in these frequency bands may have special neuroanatomical and functional organization during early visual processing.
Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 06/2013; · 3.12 Impact Factor
[show abstract][hide abstract] ABSTRACT: We report a novel boiling heat transfer (NBHT) in reduced graphene oxide (RGO) suspended in water (RGO colloid) near critical heat flux (CHF), which is traditionally the dangerous limitation of nucleate boiling heat transfer because of heater failure. When the heat flux reaches the maximum value (CHF) in RGO colloid pool boiling, the wall temperature increases gradually and slowly with an almost constant heat flux, contrary to the rapid wall temperature increase found during water pool boiling. The gained time by NBHT would provide the safer margin of the heat transfer and the amazing impact on the thermal system as the first report of graphene application. In addition, the CHF and boiling heat transfer performance also increase. This novel boiling phenomenon can effectively prevent heater failure because of the role played by the self-assembled three-dimensional foam-like graphene network (SFG).
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Despite the suitable characteristics of ropivacaine as an epidural analgesic agent, such as better preservation of motor function and less neurotoxicity, we are aware of no data on its clinical application in pain management following lumbar spine surgery. The purpose of the present study was to evaluate the preemptive analgesic effects and safety of a single epidural injection of ropivacaine during lumbar arthrodesis. METHODS: We performed a randomized, double-blinded, intention-to-treat study. Patients with planned one-level posterior lumbar interbody arthrodesis were randomly assigned to either the injection group (n = 32) or the control group (n = 34). The injection group received a 10-mL epidural injection of 0.1% ropivacaine twenty minutes before the skin incision at the planned vertebral level, and the control group received an epidural injection of 10 mL of 0.9% saline solution. A numeric rating scale (from 0 to 10) was measured at seven time points after surgery (at two, four, eight, twelve, twenty-four, and forty-eight hours and at the time of discharge), and the frequency of pushed-button patient-controlled analgesia and total fentanyl consumption were assessed at similar time points (up to two, up to four, up to eight, up to twelve, up to twenty-four, and up to forty-eight hours after surgery). Postoperative nausea and vomiting, the duration of the hospital stay, and the Likert satisfaction score at the time of discharge were evaluated. RESULTS: There were no significant differences between the two groups preoperatively. The numeric rating scale score was higher until twelve hours (p < 0.05) and the frequency of button pushes was higher at every time point except eight to twelve hours (p < 0.05) in the control group as compared with the injection group. Fentanyl consumption until eight to twelve hours (p < 0.05) and total consumption (p < 0.001) at discharge were higher in the control group. There were no differences between the two groups in terms of postoperative nausea and vomiting, the duration of hospital stay, or the mean satisfaction score, and no transient motor weakness was seen in relation to epidural injection of ropivacaine. CONCLUSIONS: A single-dose epidural injection of 0.1% ropivacaine before lumbar spine surgery is effective for reducing early postoperative pain without related complications such as transient motor weakness. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
The Journal of Bone and Joint Surgery 03/2013; 95(5):393-399. · 3.23 Impact Factor
[show abstract][hide abstract] ABSTRACT: Silicon photomultipliers (SiPMs) are outstanding photosensors for the development of compact imaging devices and hybrid imaging systems such as positron emission tomography (PET)/ magnetic resonance (MR) scanners because of their small size and MR compatibility. The wide use of this sensor for various types of scintillation detector modules is being accelerated by recent developments in tileable multichannel SiPM arrays. In this work, we present the development of a front-end readout module for multi-channel SiPMs. This readout module is easily extendable to yield a wider detection area by the use of a resistive charge division network (RCN). We applied this readout module to various PET detectors designed for use in small animal PET/MR, optical fiber PET/MR, and double layer depth of interaction (DOI) PET. The basic characteristics of these detector modules were also investigated. The results demonstrate that the PET block detectors developed using the readout module and tileable multi-channel SiPMs had reasonable performance.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 03/2013; 703:38–44. · 1.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: We propose a plasmonic structural color in the form of a thin film with a monolayer of randomly dispersed silver nanoshells. By employing spatially isotropic optical dipole antenna nanoshells to achieve efficient couplings to obliquely incident field and by utilizing local frustration and interference of randomly dispersed scatterer phases, we successfully introduce plasmonic-driven unique traits of retro-reflection as an example of a plasmonic structural color. As compared to the natural counterpart, Morpho rhetenor, a much wider reception angle, up to 70 , and a stronger retro-reflectivity of 35–45% are achieved.
[show abstract][hide abstract] ABSTRACT: To analyze the outcomes of lunate excision combined with scaphotrapeziotrapezoid arthrodesis for the treatment of advanced Kienböck disease.
Sixteen patients with Lichtman stage IIIB Kienböck disease were treated with scaphotrapeziotrapezoid arthrodesis and lunate excision and were followed for a mean of 67 months (range, 49 to 108 mo). The indications for lunate excision included pain and limited motion associated with a collapsed lunate. Clinical evaluation included range of motion, grip strength, and modified Mayo wrist score. Based on plain radiographs, the carpal height ratio, ulnar carpal distance ratio, scaphoid translation ratio, and radioscaphoid angle were measured and any presence of degenerative changes was assessed. To investigate the effects of lunate excision on the radiologic results, we compared 12 patients with stage IIIB Kienböck disease who had only scaphotrapeziotrapezoid arthrodesis as the control group.
Range of motion tended to be preserved, with a trend toward an increase in extension after surgery. Grip strength and modified Mayo score improved significantly. Fourteen patients with lunate excision demonstrated radiographic ulnar translation of the scaphoid beyond the scapholunate ridge, and radioscaphoid arthritis was observed in 4 patients. Compared to initial postoperative radiographs, the scaphoid translation ratio was significantly decreased, but neither ulnar carpal distance ratio nor radioscaphoid angle showed significant differences. In the control group, neither ulnar translation of the scaphoid nor significant changes of radiologic parameters was found between initial postoperative and final radiographs.
Scaphotrapeziotrapezoid arthrodesis with lunate excision for advanced Kienböck disease provided favorable clinical results in terms of pain relief and functional improvement. With the absence of the lunate, however, the scaphoid had a tendency to shift toward the lunate fossa. This study suggests the risk of early development of radioscaphoid arthritis as a negative effect of lunate excision.
The Journal of hand surgery 11/2012; 37(11):2226-32. · 1.33 Impact Factor
[show abstract][hide abstract] ABSTRACT: For attenuation correction (AC) in PET/MRI systems, segmentation-based methods are most often used. However, the standardized uptake value (SUV) of lesions in the bone and liver, which have higher attenuation coefficients than other organs, can be underestimated, potentially leading to misinterpretation of clinical cases. Errors in SUV estimation are also dependent on the segmentation schemes used in the segmentation-based AC. In this study, this potential bias in SUV estimation using 4 different segmentation-based AC methods was evaluated for the PET/CT data of cancer patients with bone and liver lesions. METHODS: Forty patients who had spine or liver lesions and underwent (18)F-FDG PET/CT participated (18 women and 22 men; 20 spine lesions and 20 liver lesions; mean age (±SD), 60.5 ± 11.4 y; mean body weight, 57.7 ± 10.4 kg). The patient body region was extracted from the CT image and categorized into 5 tissue groups (air, lungs, fat, water, and bone) using Hounsfield unit thresholds, which were determined from the CT histogram. Four segmentation-based AC methods (SLA [soft-tissue/lung/air], WFLA [water/fat/lung/air], SLAB [soft-tissue/lung/air/bone], and WFLAB [water/fat/lung/air/bone]) were compared with CT-based AC. The mean attenuation coefficient for each group was calculated from 40 CT images and assigned to the attenuation maps. PET sinograms were reconstructed using segmentation- and CT-based AC maps, and mean SUV in the lesions was compared. RESULTS: Mean attenuation coefficients for air, lungs, fat, water, and bone were 0.0058, 0.0349, 0.0895, 0.0987, and 0.1178 cm(-1), respectively. In the spine lesions, the SUVs were underestimated by 16.4% ± 8.5% (SLA AC) and 14.7% ± 7.5% (WFLA AC) but not to a statistically significant extent for SLAB and WFLAB AC relative to CT AC. In the liver lesions, the SUVs were underestimated by 11.1% ± 2.6%, 8.1% ± 3.0%, 6.8% ± 3.8%, and 4.1% ± 3.8% with SLA, SLAB, WFLA, and WFLAB AC, respectively. CONCLUSION: Without bone segmentation, the SUVs of spine lesions were considerably underestimated; however, the bias was acceptable with bone segmentation. In liver lesions, the segmentation-based AC methods yielded a negative bias in SUV; however, inclusion of the bone and fat segments reduced the SUV bias. The results of this study will be useful for understanding organ-dependent bias in SUV between PET/CT and PET/MRI.
Journal of Nuclear Medicine 10/2012; · 5.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: The titanate nanotube (TNT) and iron intercalated titanate nanotube (Fe-TNT) were synthesized in-situ single step hydrothermal method at 150 °C for 72 h. The electronic and local coordination structures of iron species intercalated in the interlayer space of ion exchangeable titanate nanotubes were investigated by X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopy (XPS). The iron intercalated into the nanotube was formed as hydrated iron complex of [FexII(OH)2x−1(OH2)]+ and the iron complex played a harmful role in the photocatalytic hydrogen production from methanol–water mixed solution and the photocatalytic decomposition of acid orange 7 (AO7) under UV light irradiation. A higher photocurrent generation, however, was also observed from the Fe-intercalated titanate nanotube film from 0.1 M NaOH solution under UV light irradiation.
International Journal of Hydrogen Energy 08/2012; 37(15):11081–11089. · 3.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: We demonstrate adiabatic nanofocusing of few-cycle light pulses using ultrasharp and ultrasmooth single-crystalline gold tapers. We show that the grating-induced launching of spectrally broad-band surface plasmon polariton wavepackets onto the shaft of such a taper generates isolated, point-like light spots with 10 fs duration and 10 nm diameter spatial extent at its very apex. This nanofocusing is so efficient that nanolocalized electric fields inducing strong optical nonlinearities at the tip end are reached with conventional high repetition rate laser oscillators. We use here the resulting second harmonic to fully characterize the time structure of the localized electric field in frequency-resolved interferometric autocorrelation measurements. Our results strongly suggest that these nanometer-sized ultrafast light spots will enable new experiments probing the dynamics of optical excitations of individual metallic, semiconducting, and magnetic nanostructures.
[show abstract][hide abstract] ABSTRACT: Supported and unsupported molybdenum and molybdenum carbides have been studied as catalysts of CO-H2 reactions at 570 K and atmospheric pressure. The initial turnover rates of these catalysts were comparable to those of the
more active group VIII elements. However, all molybdenum-based catalysts showed a hydrocarbon product distribution different
from those for typical group VIII metals. Furthermore, production of a large amount of CO2 (instead of water) and a high paraffin/olefin ratio reflected high activities of these catalysts for the water-gas shift
reaction and hydrogenation, respectively. The high water-gas shift reaction activity allowed a CO-rich synthesis gas to be
used efficiently over Mo-based catalysts. The CO-H2 reactions appear to be structure insensitive on molybdenum carbide catalysts, since the rates were independent of particle
size and crystal structure of unsupported catalysts and of metal loading of supported catalysts.
Research on Chemical Intermediates 05/2012; 26(5):427-443. · 0.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Glutamatergic synaptic terminals harbor reluctant synaptic vesicles (SVs) that contribute little to synchronous release during action potentials but are release competent when stimulated by sucrose or by direct intracellular application of calcium. It has been noted that the proximity of a release-competent SV to the calcium source is one of the primary factors that differentiate reluctant SVs from fast-releasing ones at the calyx of Held synapse. It has not been known whether reluctant SVs can be converted into fast-releasing ones. Here we show that reluctant SVs are recruited rapidly in an actin-dependent manner to become fast-releasing SVs once the pool of fast-releasing SVs is depleted by a short depolarization. Recovery of the pool of fast-releasing SVs was accompanied by a parallel reduction in the number of reluctant SVs. Quantitative analysis of the time course of depletion of fast-releasing SVs during high-frequency stimulation revealed that in the early phase of stimulation reluctant SVs are converted rapidly into fast-releasing ones, thereby counteracting short-term depression. During the late phase, however, after reluctant vesicles have been used up, another process of calmodulin-dependent recruitment of fast-releasing SVs is activated. These results document that reluctant SVs have a role in short-term plasticity and support the hypothesis of positional priming, which posits that reluctant vesicles are converted into fast-releasing ones via relocation closer to Ca(2+)-channels.
Proceedings of the National Academy of Sciences 03/2012; 109(13):E765-74. · 9.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: A new method to modify the acidity of zeolite was attempted to improve the activity and stability of Zn/ZSM-5 in aromatization of 2-methyl-2-butene. Pre-coking and regeneration in the presence of O2 at 773K generated a large exothermic heat in a short time, which resulted in the thermal dealumination of framework aluminum that acted as a Brønsted acid site. The treatment had a profound effect on the acid properties of the catalyst as probed by 27Al MAS NMR, temperature-programmed desorption of ammonia, and pyridine FTIR. The results showed that the concentration of oxygen in regeneration step had critical effects on the acidity and stability of Zn/ZSM-5. Thus improvement of lifetime of Zn/ZSM-5 in aromatization of 2-methyl-2-butene was achieved without deteriorating activity and selectivity by the pre-coking and controlled regeneration by oxygen.
[show abstract][hide abstract] ABSTRACT: Conventional stroke registries contain alphanumeric text-based data on the clinical status of stroke patients, but this format captures imaging data in a very limited form. There is a need for a new type of stroke registry to capture both text- and image-based data.
We designed a next-generation stroke registry containing quantitative magnetic resonance imaging (MRI) data, 'DUIH_SRegI', developed a supporting software package, 'Image_QNA', and performed experiments to assess the feasibility and utility of the system. Image_QNA enabled the mapping of stroke-related lesions on MR onto a standard brain template and the storage of this extracted imaging data in a visual database. Interuser and intrauser variability of the lesion mapping procedure was low. We compared the results from the semi automatic lesion registration using Image_QNA with automatic lesion registration using SPM5 (Statistical Parametric Mapping version 5), a well-regarded standard neuroscience software package, in terms of lesion location, size and shape, and found Image_QNA to be superior. We assessed the clinical usefulness of an image-based registry by studying 47 consecutive patients with first-ever lacunar infarcts in the corona radiata. We used the enriched dataset comprised of both image-based and alphanumeric databases to show that diffusion MR lesions overlapped in a more posterolateral brain location for patients with high NIH Stroke Scale scores (≥4) than for patients with low scores (≤3). In April 2009, we launched the first prospective image-based acute (≤1 week) stroke registry at our institution. The registered data include high signal intensity ischemic lesions on diffusion, T(2)-weighted, or fluid attenuation inversion recovery MRIs, and low signal intensity hemorrhagic lesions on gradient-echo MRIs. An interim analysis at 6 months showed that the time requirement for the lesion registration (183 consecutive patients, 3,226 MR slices with visible stroke-related lesions) was acceptable at about 1 h of labor per patient by a trained assistant with physician oversight.
We have developed a novel image-based stroke registry, with database functions that allow the formulation and testing of intuitive, image-based hypotheses in a manner not easily achievable with conventional alphanumeric stroke registries.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to identify brain areas related to apathy or depression in patients with Alzheimer disease (AD). Eighty-one AD patients were enrolled in this prospective study. (99m)Tc-HMPAO single photon emission computed tomography was performed to evaluate regional cerebral blood flow (rCBF). According to the Neuropsychiatric Inventory subscores of apathy and depression, 9 patients were classified as clinically significant (cs) depressed and non-cs-apathetic (D+) groups and 9 were classified as cs-apathetic and non-cs-depressed (A+) groups. In addition, 18 patients were classified as age-matched and Mini-Mental State Examination-matched disease control groups (D-, A-). The significance of rCBF differences between groups and the correlation between rCBF and subscores in 81 AD patients were estimated by SPM (uncorrected P < 0.005) analysis. D+ patients had significantly lower perfusion in the right orbitofrontal and inferior frontal gyri than D- patients, whereas A+ patients had this in the right amygdala, temporal, posterior cingulate, right superior frontal, postcentral, and left superior temporal gyri than A- patients. The negatively correlated areas with depression subscores included the left inferior frontal and the right middle frontal gyri and those with apathy subscores included the right temporal and right medial frontal gyri. We suggest that this finding may indicate that apathy and depression in AD patients involve distinct functional circuits.
[show abstract][hide abstract] ABSTRACT: We assessed changes in hemodynamic and arterial stiffness parameters following reductions of dialysate calcium concentrations in patients undergoing hemodialysis.
In this prospective study, 20 patients on maintenance hemodialysis (10 females, 10 males) with dialysate calcium concentrations of 1.75 mmol/L were enrolled. At the start of the study, the dialysate calcium level was lowered to 1.50 mmol/L. Serial changes in biochemical, hemodynamic, and arterial stiffness parameters, including pulse wave velocity (PWV) and augmentation index (AIx), were assessed every 2 months for 6 months. We also examined changes in the calcification-inhibitory protein, serum fetuin-A.
During the 6-month study period, serum total calcium and ionized calcium decreased consistently (9.5 ± 1.0 to 9.0 ± 0.7, p = 0.002 vs. 1.3 ± 0.1 to 1.1 ± 0.1, p = 0.035). Although no apparent changes in blood pressure were observed, heart-femoral PWW (hf-PWV) and AIx showed significant improvement (p = 0.012, 0.043, respectively). Repeated-measures ANOVA indicated a significant effect of lowering dialysate calcium on hf-PWV (F = 4.58, p = 0.004) and AIx (F = 2.55, p = 0.049). Accompanying the change in serum calcium, serum fetuin-A levels significantly increased (95.8 ± 45.8 pmol/mL at baseline to 124.9 ± 82.2 pmol/mL at 6 months, p = 0.043).
Lowering dialysate calcium concentration significantly improved arterial stiffness parameters, which may have been associated with upregulation of serum fetuin-A.
The Korean Journal of Internal Medicine 09/2011; 26(3):320-7.
[show abstract][hide abstract] ABSTRACT: Silicon photomultiplier (SiPM; also called a Geiger-mode avalanche photodiode) is a promising semiconductor photosensor in PET and PET/MRI because it is intrinsically MRI-compatible and has internal gain and timing properties comparable to those of a photomultiplier tube. In this study, we have developed a small-animal PET system using SiPMs and lutetium gadolinium oxyorthosilicate (LGSO) crystals and performed physical evaluation and animal imaging studies to show the feasibility of this system. METHODS: The SiPM PET system consists of 8 detectors, each of which comprises 2 × 6 SiPMs and 4 × 13 LGSO crystals. Each crystal has dimensions of 1.5 × 1.5 × 7 mm. The crystal face-to-face diameter and axial field of view are 6.0 cm and 6.5 mm, respectively. Bias voltage is applied to each SiPM using a finely controlled voltage supply because the gain of the SiPM strongly depends on the supply voltage. The physical characteristics were studied by measuring energy resolution, sensitivity, and spatial resolution. Various mouse and rat images were obtained to study the feasibility of the SiPM PET system in in vivo animal studies. Reconstructed PET images using a maximum-likelihood expectation maximization algorithm were coregistered with animal CT images. Results: All individual LGSO crystals within the detectors were clearly distinguishable in flood images obtained by irradiating the detector using a (22)Na point source. The energy resolution for individual crystals was 25.8% ± 2.6% on average for 511-keV photopeaks. The spatial resolution measured with the (22)Na point source in a warm background was 1.0 mm (2 mm off-center) and 1.4 mm (16 mm off-center) when the maximum-likelihood expectation maximization algorithm was applied. A myocardial (18)F-FDG study in mice and a skeletal (18)F study in rats demonstrated the fine spatial resolution of the scanner. The feasibility of the SiPM PET system was also confirmed in the tumor images of mice using (18)F-FDG and (68)Ga-RGD and in the brain images of rats using (18)F-FDG. CONCLUSION: These results indicate that it is possible to develop a PET system using a promising semiconductor photosensor, which yielded reasonable PET performance in phantom and animal studies.
Journal of Nuclear Medicine 03/2011; 52(4):572-9. · 5.77 Impact Factor