96 results on '"Ohara, S."'
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2. Attention to painful cutaneous laser stimuli evokes directed functional connectivity between activity recorded directly from human pain-related cortical structures
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Liu, C.-C., Ohara, S., Franaszczuk, P.J., and Lenz, F.A.
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PAIN management , *CEREBRAL cortex , *FRONTAL lobe , *EVOKED potentials (Electrophysiology) , *ATTENTION , *EPILEPSY , *BIOLOGICAL neural networks , *STATISTICAL hypothesis testing - Abstract
Abstract: Our previous studies show that attention to painful cutaneous laser stimuli is associated with functional connectivity between human primary somatosensory cortex (SI), parasylvian cortex (PS), and medial frontal cortex (MF), which may constitute a pain network. However, the direction of functional connections within this network is unknown. We now test the hypothesis that activity recorded from the SI has a driver role, and a causal influence, with respect to activity recorded from PS and MF during attention to a laser. Local field potentials (LFP) were recorded from subdural grid electrodes implanted for the treatment of epilepsy. We estimated causal influences by using the Granger causality (GRC), which was computed while subjects performed either an attention task (counting laser stimuli) or a distraction task (reading for comprehension). Before the laser stimuli, directed attention to the painful stimulus (counting) consistently increased the number of GRC pairs both within the SI cortex and from SI upon PS (SI>PS). After the laser stimulus, attention to a painful stimulus increased the number of GRC pairs from SI>PS, and SI>MF, and within the SI area. LFP at some electrode sites (critical sites) exerted GRC influences upon signals at multiple widespread electrodes, both in other cortical areas and within the area where the critical site was located. Critical sites may bind these areas together into a pain network, and disruption of that network by stimulation at critical sites might be used to treat pain. Electrical activity recorded from the somatosensory cortex drives activity recorded elsewhere in the pain network and may bind the network together; disruption of that network by stimulation at critical sites might be used to treat pain. [Copyright &y& Elsevier]
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- 2011
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3. Painful stimuli evoke potentials recorded from the medial temporal lobe in humans
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Liu, C.C., Ohara, S., Franaszczuk, P., Zagzoog, N., Gallagher, M., and Lenz, F.A.
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PAIN perception , *EVOKED potentials (Electrophysiology) , *BRAIN physiology , *TEMPORAL lobe , *CONDITIONED response , *FEAR , *HUMAN behavior - Abstract
Abstract: The role of human medial temporal structures in fear conditioning has led to the suggestion that neurons in these structures might respond to painful stimuli. We have now tested the hypothesis that recordings from these structures will demonstrate potentials related to the selective activation of cutaneous nociceptors by a painful laser stimulus (laser evoked potential, LEP) (Kenton B, Coger R, Crue B, Pinsky J, Friedman Y, Carmon A (1980) Neurosci Lett 17:301–306). Recordings were carried out through electrodes implanted bilaterally in these structures for the investigation of intractable epilepsy. Reproducible LEPs were commonly recorded both bilaterally and unilaterally, while LEPs were recorded at contacts on the left (9/14, P=0.257) as commonly as on the right (5/14), independent of the hand stimulated. Along electrodes traversing the amygdala the majority of LEPs were recorded from dorsal contacts near the central nucleus of the amygdala and the nucleus basalis. Stimulus evoked changes in theta activity were observed at contacts on the right at which isolated early negative LEPs (N2*) responses could be recorded. Contacts at which LEPs could be recorded were as commonly located in medial temporal structures with evidence of seizure activity as on those without. These results demonstrate the presence of pain-related inputs to the medial temporal lobe where they may be involved in associative learning to produce anxiety and disability related to painful stimuli. [Copyright &y& Elsevier]
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- 2010
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4. EFFICIENT EXTRACTION OF POLYPHENOLICS FROM THE BARK OF TROPICAL TREE SPECIES.
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Makino, R., Ohara, S., and Hashida, K.
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POLYPHENOLS , *SUGAR analysis , *MANGIUM , *EARLEAF acacia , *JAPANESE larch , *TREES - Abstract
The objective of this study was to discover a method for extracting polyphenolics containing as few sugar components as possible. In this work, water extraction was carried out for the bark of several tropical tree species under various temperature conditions to compare the extractability of polyphenolics and sugar components. The yield and total polyphenolics content of the extracts increased with increase in extraction temperature. Total polyphenolics at 100 °C from Acacia mangium, Acacia auriculiformis, Rhizophora apiculata and Larix leptolepis were 14.2, 12.9, 8.0 and 5.3% respectively. Total sugar contents from A. mangium and L. leptolepis, which were determined using a slightly modified phenol-sulphuric acid method, were almost constant at 20-80 °C, but increased substantially at 100 °C. The same trend was observed with total reducing sugar contents from these two species. Our results suggest that water extraction at 80 °C from the barks of A. mangium and L. leptolepis is a good method for the extraction of polyphenolics with very few sugar components. [ABSTRACT FROM AUTHOR]
- Published
- 2009
5. Neural activities of tactile cross-modal working memory in humans: an event-related potential study
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Ohara, S., Wang, L., Ku, Y., Lenz, F.A., Hsiao, S.S., Hong, B., and Zhou, Y.-D.
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MEMORY , *NEUROPHYSIOLOGY , *TOUCH -- Psychological aspects , *CONDITIONED response - Abstract
Abstract: In the present study, we examined the neural mechanisms underlying cross-modal working memory by analyzing scalp-recorded event-related potentials (ERPs) from normal human subjects performing tactile–tactile unimodal or tactile–auditory cross-modal delay tasks that consisted of stimulus-1 (S-1, tactile), interval (delay), and stimulus-2 (S-2, tactile or auditory). We hypothesized that there would be sequentially discrete task-correlated changes in ERPs representing neural processes of tactile working memory, and in addition, significant differences would be observed in ERPs between the unimodal task and the cross-modal task. In comparison to the ERP components in the unimodal task, two late positive ERP components (LPC-1 and LPC-2) evoked by the tactile S-1 in the delay of the cross-modal task were enhanced by expectation of the associated auditory S-2 presented at the end of the delay. Such enhancement might represent neural activities involved in cross-modal association between the tactile stimulus and the auditory stimulus. Later in the delay, a late negative component (LNC) was observed. The amplitude of LNC depended on information retained during the delay, and when the same information was retained, this amplitude was not influenced by modality or location of S-2 (auditory S-2 through headphones, or tactile S-2 on the left index finger). LNC might represent the neural activity involved in working memory. The above results suggest that the sequential ERP changes in the present study represent temporally distinguishable neural processes, such as the cross-modal association and cross-modal working memory. [Copyright &y& Elsevier]
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- 2008
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6. Analysis of synchrony demonstrates that the presence of “pain networks” prior to a noxious stimulus can enable the perception of pain in response to that stimulus.
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Ohara, S., Crone, N. E., Weiss, N., Kim, J. H., and Lenz, F. A.
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PAIN perception , *SENSORY perception , *ELECTRODES , *CEREBRAL cortex , *EPILEPSY - Abstract
Our previous study has shown that directed attention to a painful stimulus is associated with increased synchrony between electrocorticographic (ECoG) oscillations in pain-related cortical structures. We now test the hypothesis that the synchrony or functional connectivity of this pain network differs between events during which pain is or is not perceived (pain or non-pain events) in response to a noxious cutaneous laser stimulus. ECoG recordings were made through subdural electrodes implanted in a patient for the treatment of epilepsy. The patient was instructed that the stimulus could be painful or non-painful on any given presentation. Synchrony between ECoG signals at different sites was measured during the pre-stimulus interval, and the difference in the number of sites with significant pre-stimulus synchrony was compared between pain and non-pain events. Pre-stimulus synchrony was more common during pain versus non-pain events among electrodes overall, and in the subset of electrodes at which laser-evoked potentials (LEPs) were recorded. This difference between pain and non-pain events was also significant for the subset of electrodes over medial cortex, including anterior cingulate cortex (ACC), but not for subsets of electrodes over the superior and inferior convexity, including primary somatosensory (S1) and parasylvian cortex (PS), respectively. These results suggest that dynamic changes in the functional connectivity between ACC and other cortical regions enable the perception of pain in response to noxious stimuli. [ABSTRACT FROM AUTHOR]
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- 2008
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7. Nanoparticles synthesis using supercritical fluid technology – towards biomedical applications
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Byrappa, K., Ohara, S., and Adschiri, T.
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FLUIDS , *NANOPARTICLES , *PHARMACEUTICAL technology , *DRUG delivery systems - Abstract
Abstract: Supercritical fluid (SCF) technology has become an important tool of materials processing in the last two decades. Supercritical CO2 and H2O are extensively being used in the preparation of a great variety of nanomaterials. The greatest requirement in the application of nanomaterials is its size and morphology control, which determine the application potential of the nanoparticles, as their properties vary significantly with size. Although significance of SCF technology has been described earlier by various authors, the importance of this technology for the fabrication of inorganic and hybrid nanomaterials in biomedical applications has not been discussed thoroughly. This review presents the nanomaterial preparation systematically using SCF technology with reference to the processing of biomedical materials. The basic principles of each one of the processes have been described in detail giving their merits and perspectives. The actual experimental data and results have been discussed in detail with respect to the selected nanomaterials for biomedical applications. The SCF synthesis of nanoparticles like phosphors, magnetic materials, carbon nanotubes, etc. have been discussed as they have potential applications in bio-imaging, hyperthermia, cancer therapy, neutron capture therapy, targeted drug delivery systems and so on. The more recent approach towards the in situ surface modification, dispersibility, single nanocrystal formation, and morphology control of the nanoparticles has been discussed in detail. [Copyright &y& Elsevier]
- Published
- 2008
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8. Spontaneous low threshold spike bursting in awake humans is different in different lateral thalamic nuclei.
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Ohara, S., Taghva, A., Kim, J. H., and Lenz, F. A.
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MOTOR ability , *PSYCHOLOGY of movement , *THALAMUS , *GLOBUS pallidus , *CALCIUM , *PATIENTS - Abstract
Spontaneous action potential bursts associated with low threshold calcium spikes (LTS) occur in multiple human lateral thalamic nuclei, each with different physiologic characteristics. We now test the hypothesis that different patterns of spontaneous LTS bursting occur in these nuclei during awake surgery in patients with essential tremor and the arm at rest. This protocol was chosen to minimize the effect of the patient’s disease upon thalamic activity which is a potential confound in a surgical study of this type. Neuronal activity was studied in the human thalamic nuclei receiving somatic sensory input (Vc, ventral caudal), input from the deep cerebellar nuclei (Vim, ventral intermediate), or input from the pallidum (Vo, ventral oral). In each nucleus the burst rates were significantly greater than zero. Burst rates were higher in Vc than in Vim, while firing rates were lower. These findings suggest that neurons in Vc are hyperpolarized and have more frequent inhibitory events. Pre-burst inter-spike intervals (ISIs) were significantly longer in Vc, but were significantly shorter when corrected for the average ISIs between bursts (burst rate/inverse of the primary event rate). These results suggest that inhibitory events in Vc are of lower magnitude relative to a hyperpolarized resting membrane potential. Studies in many species demonstrate that input from the pallidum to the thalamus is inhibitory, suggesting that input to Vo is predominantly inhibitory. However, neurons in Vo have neither slower firing rates nor more frequent LTS bursts. Previous studies have found that spontaneous LTS is similar between classes of neurons within Vc, as defined by their response to thermal and painful stimuli. The differences in spontaneous LTS between human nuclei but not between functional classes within a nucleus may be a basic organizing principle of thalamic inhibitory circuitry. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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9. Hydrothermal synthesis and in situ surface modification of boehmite nanoparticles in supercritical water
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Mousavand, T., Ohara, S., Umetsu, M., Zhang, J., Takami, S., Naka, T., and Adschiri, T.
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NANOPARTICLES , *CRYSTAL grain boundaries , *CRYSTAL growth , *PARTICLES - Abstract
Abstract: In situ surface modification of boehmite (AlOOH) nanoparticles during hydrothermal synthesis in supercritical water was examined by adding CH3(CH2)4CHO and CH3(CH2)5NH2 as modifier reagents to the reactants. Changes in surface properties of the nanoparticles by surface modification was observed by FTIR, dispersion in solvents and TEM analyses, which demonstrated that reagents chemically binded onto the surface of the AlOOH nanoparticles. The results of SEM and TEM pictures show that the surface modification affects crystal growth and reduces the particle size and changes the morphology of the particles. [Copyright &y& Elsevier]
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- 2007
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10. The prevalence of Helicobacter pylori infection and the status of gastric acid secretion in patients with gastroesophageal junction adenocarcinoma in Japan.
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Koike, T., Ohara, S., Inomata, Y., Abe, Y., Iijima, K., and Shimosegawa, T.
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HELICOBACTER pylori infections , *ESOPHAGUS diseases , *GASTROESOPHAGEAL reflux , *BARRETT'S esophagus , *ADENOCARCINOMA - Abstract
We have previously reported that H. pylori infection prevents reflux esophagitis (RE) and Barrett’s esophagus (BE) by decreasing gastric acid secretion. Gastroesophageal (GE) junction adenocarcinoma, including Barrett’s adenocarcinoma, has been thought to be a complication of gastroesophageal reflux disease. However, the relationship between H. pylori infection, gastric acid secretion and GE junction adenocarcinoma had not yet been investigated in Japan. We demonstrated that the status of gastric acid secretion was higher in patients with GE junction adenocarcinoma than in patients with early gastric cancer (EGC), and that the level was the same in patients with RE and those with BE. We also found that the prevalence of H. pylori infection in patients with GE junction adenocarcinoma was significantly lower than that in patients with EGC, although not as low as that in patients with RE and BE, suggesting that preservation of gastric acid secretion may be important for the development of GE junction adenocarcinoma in Japanese people, regardless of the presence of H. pylori infection. [ABSTRACT FROM AUTHOR]
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- 2007
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11. Analysis of synchrony demonstrates ‘pain networks’ defined by rapidly switching, task-specific, functional connectivity between pain-related cortical structures
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Ohara, S., Crone, N.E., Weiss, N., and Lenz, F.A.
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PAIN , *HIGHER nervous activity , *NOCICEPTORS , *NERVOUS system - Abstract
Abstract: Imaging studies indicate that experimental pain is processed in multiple cortical areas which are often characterized as a network. However, the functional connectivity within the network and the other properties of the network is poorly understood. Substantial evidence demonstrates that synchronous oscillations between two cortical areas may indicate functional connectivity between those areas. We test the hypothesis that cortical areas with pain-related activity are functionally connected during attention to a painful stimulus. We stimulated with a painful, cutaneous, laser stimulus and recorded the response directly from the cortical surface (electrocorticography – ECoG) over primary somatosensory (SI), parasylvian (PS), and medial frontal (MF) cortex through subdural electrodes implanted for treatment of epilepsy. The results demonstrate synchrony of ECoGs between cortical structures receiving input from nociceptors, as indicated by the occurrence of laser-evoked potentials (LEPs) and/or event-related desynchronization (ERD). Prior to the stimulus, directed attention to the painful stimulus consistently increased the degree of synchrony between SI and PS regions, as the subject anticipated the stimulus. After the laser stimulus, directed attention to the painful stimulus consistently increased the degree of synchrony between SI and MF cortex, as the subject responded by counting the stimulus. Therefore, attention to painful stimuli always enhanced synchrony between cortical pain-related structures. The pattern of this synchrony changed as the patient switched tasks from anticipation of the stimulus to counting the stimulus. These results are the first compelling evidence of pain networks characterized by rapidly switching, task-specific functional connectivity. [Copyright &y& Elsevier]
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- 2006
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12. Sequential neural processes of tactile–visual crossmodal working memory
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Ohara, S., Lenz, F., and Zhou, Y.-D.
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SHORT-term memory , *PREFRONTAL cortex , *ELECTROENCEPHALOGRAPHY , *ANALYSIS of covariance - Abstract
Abstract: Working memory is essential to learning and performing sensory-motor behaviors that in many situations require the integration of stimuli of one modality with stimuli of another. In the present study, we focused on the neural mechanisms underlying crossmodal working memory. We hypothesized that in performance of the tactile crossmodal working memory task, there would be sequentially discrete task-correlated neural activities representing the processes of crossmodal working memory. Scalp-recorded event-related potentials were collected from 15 electrodes in humans performing each of four tasks: tactile–tactile unimodal delayed matching-to-sample task, tactile–visual crossmodal delayed matching-to-sample task, tactile unimodal control spatial task, and tactile crossmodal control spatial task. Two positive event-related potential peaks were observed during the delay of the task. One peak (late positive component-1) was at about 330 ms after the onset of the tactile stimulus, and the other (late positive component-2) was at about 600 ms. Late positive component-1 was observed in all four tasks. There was no significant difference in late positive component-1 either between the unimodal tasks, or between the crossmodal tasks, but late positive component-1 was significantly larger in the crossmodal tasks than that in the unimodal tasks, and showed a specific pattern of larger activity over parietal areas than activity over frontal areas. Late positive component-2 was not observed in the unimodal matching task but was observed in all other three tasks over parietal areas. During the late delay (1000 ms–1500 ms), significant differences in negative potentials (late negative component) were found between the tasks. The present study shows sequential changes in event-related potentials during the retention period of working memory tasks. It indicates that in performance of a crossmodal working memory task, there are sequentially discrete neural processes that may represent neural activities related to different cognitive functions, such as crossmodal transfer of information, and the working memory of the stimulus. [Copyright &y& Elsevier]
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- 2006
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13. Modulation of somatosensory event-related potential components in a tactile–visual cross-modal task
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Ohara, S., Lenz, F.A., and Zhou, Y.-D.
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SOMATOSENSORY evoked potentials , *EVOKED potentials (Electrophysiology) , *ELECTROENCEPHALOGRAPHY , *TOUCH - Abstract
Abstract: Human tactile discrimination studies have shown that visual stimuli enhance tactile performance. Other studies on event-related potentials showed that somatosensory N140 was enhanced when attention of human subjects was directed to tactile stimuli. Therefore, we hypothesized that N140 would be modulated when human subjects performed tactile cross-modal delay tasks. Scalp-event-related potentials were recorded from normal subjects performing either a tactile–tactile unimodal, or a tactile–visual cross-modal delayed matching-to-sample task. Identical tactile stimuli were used in both tasks. N140 component evoked by the tactile stimuli was enhanced in the cross-modal task. Enhancement of this component was also observed in control cross-modal tasks. The results suggest that tactile–visual cross-modal association affects tactile sensory-perceptual processes in humans. [Copyright &y& Elsevier]
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- 2006
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14. Psychophysics of CNS Pain-Related Activity: Binary and Analog Channels and Memory Encoding.
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Bagley, C. A., Ohara, S., Lawson, H. C., and Lenz, F. A.
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PROSENCEPHALON , *PAIN , *THALAMUS , *NEURONS , *NEURAL stimulation - Abstract
The forebrain neuronal system signaling pain has been poorly characterized. The pain pathway afferent to the thalamus may be a labeled line consisting of neurons in the pain-signaling pathway to the brain (spinothalamic tract, STT) that respond only to painful stimuli. It has recently been proposed that the STT contains a series of analog-labeled lines, each signaling a different aspect of the internal state of the body (interoception), for example, visceral/cold/itch sensations. In this view, pain is the unpleasant emotion produced by disequilibrium of the internal state. The authors now show that stimulation of an STT receiving zone (thalamic principal somatic sensory nucleus, ventral caudal) in awake humans produces two different exteroceptive responses. The first is a binary response signaling the presence of painful stimuli. The second is an analog response in which nonpainful and painful sensations are graded with intensity of the stimulus. Such stimulation can evoke both the sensory and emotional components of previously experienced pain. These results illustrate the diverse functions of human pain signaling pathways. [ABSTRACT FROM AUTHOR]
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- 2006
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15. Characterisation of YAG:Ce powders thermal treated at different temperatures
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Del Rosario, G., Ohara, S., Mancic, L., and Milosevic, O.
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CERIUM , *LUMINESCENCE , *AEROSOLS , *SURFACE roughness - Abstract
Submicronic, spherical, polycrystalline YAG:Ce powders with luminescence properties were synthesised through aerosol processing route from the corresponding nitrates solution. Additional heat treatment was performed in the temperature range from 1000 to 1200 °C in order to increase the crystallinity of the obtained cubic garnet phase. SEM examination and subsequent morphological analysis allowed studying the surface properties and particle size distributions. An Image Processor was used to measure particle surface roughness. Quantitative SEM/EDS analysis indicated the synthesised materials present high purity and compositional homogeneity. TEM and selected area electron diffraction (SAED) showed a high crystallinity of the samples. XRD patterns of the powders were recorded in the region of 2θ = 10°–80°. The evolution of crystallite size was performed measuring of the broadening of a particular peak using the Scherrer equation. It was found that the crystallite size and bulk particles size vary with the applied temperature. The observed changes in function of the different thermal treatments were correlated with the photoluminescence (PL) properties of these materials. [Copyright &y& Elsevier]
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- 2004
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16. Short-term effect of buformin, a biguanide, on insulin sensitivity, soluble fraction of tumor necrosis factor receptor and serum lipids in overweight patients with type 2 diabetes mellitus
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Ohara, S., Komatsu, R., and Matsuyama, T.
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OVERWEIGHT persons , *DIABETES , *THERAPEUTICS , *CARDIOVASCULAR diseases - Abstract
Aims/hypothesis: The UK Prospective Diabetes Study (UKPDS) showed that biguanide therapy in overweight patients reduced the risk for any diabetes-related endpoint and all-cause mortality. Biguanides lower the blood glucose values without stimulation of insulin release. We have investigated the short-term effect of buformin on insulin sensitivity, solved tumor necrosis factor receptors (sTNFRs), and serum lipids in overweight subjects with type 2 diabetes mellitus (DM). Method: Thirteen overweight subjects with type 2 DM were examined. The subjects who were fed 20 kcal/kg body weight were divided into two subgroups according to whether they were treated by buformin (Buformin group), or dietary therapy alone (Diet group). Six patients were in Buformin group and seven patients were in Diet group. We calculated insulin-mediated glucose uptake by the liver and peripheral tissues using euglycemic hyperinsulinemic clamp combined with an oral glucose load before and after buformin treatment or diet therapy for 2 weeks. Results: Fasting plasma glucose, total cholesterol (T-chol), LDL-cholesterol (LDL-chol), and sTNFR2 were significantly decreased, and hepatic glucose uptake significantly increased from
32±7 to42±7 % (P<0.05 ) in Buformin group but did not changed significantly in Diet group. However, the glucose infusion rate thought to express insulin sensitivity in peripheral tissue, TNF-α, sTNFR1, fasting plasma insulin, C-peptide, and NEFA levels did not change significantly in both the groups after treatment. Conclusion/interpretation: Buformin improved insulin sensitivity in the liver and decreased T-chol, LDL-chol, and sTNFR2. The mechanism of action for buformin likely involves inhibition of TNF-α. Buformin lowers insulin resistance and risk factors for cardiovascular disease including serum lipid and will therefore, be useful in management of overweight type 2 DM patients. [Copyright &y& Elsevier]- Published
- 2004
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17. Ultra-wideband amplifiers based on Bi2O3-EDFAs
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Ohara, S., Sugimoto, N., Ochiai, K., Hayashi, H., Fukasawa, Y., Hirose, T., Nagashima, T., and Reyes, M.
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DIGITAL communications , *BANDWIDTHS , *ELECTRONIC pulse techniques , *PHYSICAL & theoretical chemistry - Abstract
We demonstrate broadband amplification over (C + L)-band or extended L-band using fusion-spliceable Bi2O3-based erbium doped fiber (EDF). A power conversion efficiency (PCE) of 39% is achieved. In a single-stage amplifier we achieved a 3 dB bandwidth of 75 nm. In addition we showed very low four-wave mixing in an extended L-band amplifier by reducing the length of fiber required to a few meters. [Copyright &y& Elsevier]
- Published
- 2004
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18. Gastric Acid Secretion of Normal Japanese Subjects in Relation to Helicobacter pylori Infection, Aging, and Gender.
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Iijima, K., Ohara, S., Koike, T., Sekine, H., and Shimosegawa, T.
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HELICOBACTER pylori infections , *GASTRIC acid , *AGE factors in disease , *SEX factors in disease , *SECRETION - Abstract
Background: In Japan. where the incidence of gastric cancer is high. Helicobacter pylori infection could affect gastric acid secretion differently from that in Western countries. The aim of this study was to investigate the relationship between H. pylori infection, acid secretion, aging, and gender in normal Japanese subjects. Methods: The study comprised 193 Japanese subjects who had undergone routine endoscopy. Gastrin-simulated acid output was performed during the routine endoscopic examination using the endoscopic method of gastric acid secretory testing (EGT: endoscopic gastrin test), which has been reported previously. H. pylori status was determined by histology, rapid urease test, and serology. Results: Mean EGT values were 3.9 ± 1.5 mEq/10 min in H. pylori-negative men, 1.6 ± 2.5 in H. pylori-positive men, 2.2 ± 0.9 in H. pylori-negative women, and 1.5 ± 1.2 in H. pylori-positive women. Although acid secretion was lower in H. pylori-positive subjects compared with H. pylori-negative subjects in both men and women, the decrease was more marked in men with H. pylori infection. Multiple linear regression analysis showed that aging is positively associated with gastric acid secretion in the H. pylori-negative subjects, whereas a negative association was found between them in the H. pylori-positive subjects. Conclusions: In Japanese subjects, aging affects gastric acid secretion differently depending on the status of H. pylori infection. H. pylori infection showed a stronger inhibitory effect on the acid secretion in men than in women. This gender-related difference in the susceptibility acid secretion to H. pylori infection may explain the higher rates of gastric cancer in men in Japan. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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19. Amplitudes of laser evoked potential recorded from primary somatosensory, parasylvian and medial frontal cortex are graded with stimulus intensity
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Ohara, S., Crone, N.E., Weiss, N., Treede, R.-D., and Lenz, F.A.
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BRAIN diseases , *LASERS , *DEVELOPMENTAL disabilities , *PARASYMPATHETIC nervous system - Abstract
Intensity encoding of painful stimuli in many brain regions has been suggested by imaging studies which cannot measure electrical activity of the brain directly. We have now examined the effect of laser stimulus intensity (three energy levels) on laser evoked potentials (LEPs) recorded directly from the human primary somatosensory (SI), parasylvian, and medial frontal cortical surfaces through subdural electrodes implanted for surgical treatment of medically intractable epilepsy. LEP N2* (early exogenous/stimulus-related potential) and LEP P2** (later endogenous potential) amplitudes were significantly related to the laser energy levels in all regions, although differences between regions were not significant. Both LEP peaks were also significantly correlated with the pain intensity evoked by the laser stimulus, excepting N2* over the parasylvian region. Peak latencies of both LEP peaks were independent of laser energy levels.N2* and P2** amplitudes of the maxima in all regions showed significant positive linear correlations with laser energy, excepting N2* over the parasylvian region. The lack of correlation of parasylvian cortical N2* with laser energy and pain intensity may be due to the unique anatomy of this region, or the small sample, rather than the lack of activation by the laser. Differences in thresholds of the energy correlation with amplitudes were not significant between regions. These results suggest that both exogenous in endogenous potentials evoked by painful stimuli, and recorded over SI, parasylvian, and medial frontal cortex of awake humans, encode the intensity of painful stimuli and correlate with the pain evoked by painful stimuli. [Copyright &y& Elsevier]
- Published
- 2004
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20. Comparison between a new 13C-urea breath test, using a film-coated tablet, and the conventional 13C-urea breath test for the detection of Helicobacter pylori infection.
- Author
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Ohara S, Kato M, Saito M, Fukuda S, Kato C, Hamada S, Nagashima R, Obara K, Suzuki M, Honda H, Asaka M, and Toyota T
- Abstract
BACKGROUND: In Japan, urea breath-testing includes mouth rinsing with water immediately after the ingestion of (13)C-urea solution, to prevent false-positive results that are caused by oral bacteria with urease activity. Our objective was to evaluate the diagnostic performance of a urea breath test using a film-coated (13)C-urea tablet and omitting mouth rinsing. METHODS: The study was a multicenter trial comparing the solution- and tablet-based urea breath tests (UBTs). Helicobacter pylori status was determined by histology, culture, and rapid urease testing. RESULTS: Of the 255 subjects who completed the study, evaluation of the tablet-based UBT was possible in 254, and comparison of the tablet-based UBT and the solution-based UBT was possible in 250 patients. When the assessment achieved by a combination of biopsy-based methods was used as a reference standard, the sensitivity, specificity, and accuracy of the tablet-based method were determined to be 97.7%, 98.4%, and 98.0%, respectively. When the results of the solution-based UBT were used as a reference standard, the sensitivity, specificity, and accuracy of the tablet-based UBT were determined to be 96.9%, 97.6%, and 97.2%, respectively. CONCLUSIONS: The (13)C-urea tablet-based method proved to be a simple and accurate test for the diagnosis of H. Pylori infection. Mouth rinsing was not required. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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21. Attention to a painful cutaneous laser stimulus modulates electrocorticographic event-related desynchronization in humans
- Author
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Ohara, S., Crone, N.E., Weiss, N., and Lenz, F.A.
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EVOKED potentials (Electrophysiology) , *ELECTROPHYSIOLOGY , *PAIN , *LASERS , *PHYSIOLOGY - Abstract
Objective: To test the hypothesis that attention to painful cutaneous laser stimuli enhances event-related desynchronization (ERD) in cortical regions receiving nociceptive input.Methods: We used wavelet time–frequency analysis and bandpass filtering to measure ERD quantitatively in subdural electrocorticographic recordings while subjects either attended to, or were distracted from, a painful cutaneous laser stimulus.Results: ERD were observed over primary somatosensory and parasylvian (PS) cortices in all 4 subjects, and over medial frontal cortex in 1 subject. Laser-evoked potentials were also observed in all 3 regions. In all subjects, ERD was more widespread and intense, particularly over PS, during attention to laser stimuli (counting stimuli) than during distraction from the stimuli (reading for comprehension).Conclusions: These findings suggest that pain-associated ERD is modulated by attention, particularly over PS.Significance: This study suggests that thalamocortical circuits are involved in attentional modulation of pain because of the proposed role of these circuits in the mechanisms of ERD. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
22. Allodynia in patients with post-stroke central pain (CPSP) studied by statistical quantitative sensory testing within individuals
- Author
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Greenspan, J.D., Ohara, S., Sarlani, E., and Lenz, F.A.
- Subjects
- *
ALLODYNIA , *BRAIN , *PAIN , *PATIENTS - Abstract
The disinhibition hypothesis of post-stroke central pain (CPSP) suggests that ‘the excessive response (dysesthesia/hyperalgesia/allodynia) is accompanied by a…loss of sensation’ resulting from a lesion of a ‘lateral nucleus’ of thalamus or of ‘cortico-thalamic paths’ [Brain 34 (1911) 102]. One recent elaboration of this hypothesis proposes a submodality specific relationship, such that injury to a cool-signaling lateral thalamic pathway disinhibits a nociceptive medial thalamic pathway, thereby producing both burning, cold, ongoing pain and cold allodynia. The current study quantitatively evaluated the sensory loss and sensory abnormalities to discern submodality relationships between these sensory features of CPSP. The present results were statistically tested within individuals so that sensory loss and sensory abnormality are directly related by occurrence in the same individual.The results demonstrate that individuals with CPSP and normal tactile detection thresholds experience tactile allodynia significantly more often than those with tactile hypoesthesia. Most patients (11/13) exhibited hypoesthesia for the perception of cool stimuli, but few of these (2/11) showed cold allodynia. The most dramatic case of cold allodynia occurred in a patient who had a normal detection threshold for cold. Individuals with cold hypoesthesia, strictly contralateral to the cerebro-vascular accident (CVA or stroke), were often characterized by the presence of burning, cold, ongoing pain, and by the absence, not the presence, of cold allodynia. Overall, these results in CPSP suggest that tactile allodynia occurs in disturbances of thermal/pain pathways that spare the tactile-signaling pathways, and that cold hypoesthesia is neither necessary nor sufficient for cold allodynia. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
23. Cutaneous painful laser stimuli evoke responses recorded directly from primary somatosensory cortex in awake humans.
- Author
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Ohara S, Crone N E, Weiss N, Treede R-D, and Lenz F A
- Subjects
- *
SOMATOSENSORY evoked potentials , *DEVELOPMENTAL disabilities , *BRAIN diseases , *SENSORY receptors - Abstract
Negative and positive laser evoked potential (LEP) peaks (N2*, P2**) were simultaneously recorded from the primary somatosensory (SI), parasylvian, and medial frontal (MF: anterior cingulate and supplementary motor area) cortical surfaces through subdural electrodes implanted for the surgical treatment of intractable epilepsy. Distribution of the LEP N2* and P2** peaks was estimated to be in cortical areas (SI, parasylvian, and MF) identified by anatomic criteria, by their response to innocuous vibratory stimulation of a finger (v-SEP), and to electrical stimulation of the median nerve (e-SEP). The maximum of the LEP N2* peak was located on the CS, medial (dorsal) to the finger motor area, as determined by cortical stimulation, and to the finger somatosensory area, as determined from the e-SEP and v-SEP. This finding suggests that the generator source of the LEP N2* peak in SI was different from that of e-SEP or v-SEP in Brodmann's areas 3b or 1. In parasylvian and MF, polarity reversal was often observed, indicating tangential current sources in these regions. In contrast to e-SEP and v-SEP, the LEP N2* latency over SI was not shorter than that over the parasylvian region. The amplitude of N2* was larger over SI than over MF and the latencies of the LEP peaks in those 2 regions were different. These findings provide evidence for a significant LEP generator in the postcentral gyrus, perhaps SI cortex, that is situated outside the tactile homunculus in SI and that receives its input arising from nociceptors simultaneously with parasylvian and MF cortex. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
24. Trace gas monitor based on difference frequency generation at 4 μm using mass-production laser diodes as pump and signal light sources.
- Author
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Takahashi, M., Ohara, S., Tezuka, T., Ashizawa, H., Endo, M., Yamaguchi, S., Nanri, K., and Fujioka, T.
- Subjects
- *
LASERS , *DIODES , *OPTICAL fibers , *LITHIUM niobate , *ABSORPTION spectra , *LIGHT amplifiers - Abstract
New pump and signal laser sources for difference frequency generation (DFG) at 4 μm are described. A laser diode with a 980 nm fiber Bragg grating and a 785 nm Fabry-Perot (FP) laser diode were coupled into an optical fiber and mixed in a periodically poled Mg-doped lithium niobate (PPMgLN ) crystal, resulting in efficient mid-IR DFG. The DFG power was measured to be 0.23 μW for a pump power of 5 mW and a signal power of 50 mW with a slope efficiency of 0.92 mW/W[sup 2]. A Doppler-broadened absorption spectrum of N[sub 2]O at 2485.2 cm[sup -1] (3.927 μm) was observed in a 0.1 m-long gas cell at a pressure of 133 Pa. The spectral linewidth of the DFG source was estimated to be 161 MHz (FWHM) for an averaging time of 700 ms. Real-time monitoring of N[sub 2]O in a multipass cell with an optical path length of 36 m at a concentration level of 1 ppm was demonstrated. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
- View/download PDF
25. The effects of lansoprazole on erosive reflux oesophagitis are influenced by CYP2C19 polymorphism.
- Author
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Kawamura, M., Ohara, S., Koike, T., Iijima, K., Suzuki, J., Kayaba, S., Noguchi, K., Hamada, S., Noguchi, M., and Shimosegawa, T.
- Subjects
- *
ESOPHAGUS , *GASTRIC acid - Abstract
Summary Background : The acid suppressive effect of lansoprazole is influenced by the P450 2C19 (CYP2C19) polymorphism. Aim : To investigate whether the CYP2C19 genotype is related to the healing of erosive reflux oesophagitis during treatment with lansoprazole. Methods : Eighty-eight Japanese patients with erosive reflux oesophagitis were treated with a daily oral dose of 30 mg lansoprazole for 8 weeks. The CYP2C19 genotype, Helicobacter pylori infection status and serum pepsinogen I/II ratio were assessed before treatment. At 4 and 8 weeks, the healing of erosive reflux oesophagitis was evaluated endoscopically. Results : The healing rates were 57.1%, 69.2% and 72.7% at 4 weeks and 77.4%, 95.0% and 100% at 8 weeks in homozygous extensive metabolizers, heterozygous extensive metabolizers and poor metabolizers, respectively. At 8 weeks, the healing rate of erosive reflux oesophagitis was significantly lower in homozygous extensive metabolizers than in the other two groups (P < 0.05). The H. pylori status and serum pepsinogen I/II ratio had less influence than CYP2C19 polymorphism on the healing rate of erosive reflux oesophagitis. Conclusions : The therapeutic effect of lansoprazole on erosive reflux oesophagitis is influenced by the CYP2C19 genotype status. Therefore, a test of CYP2C19 genotype may be useful for the medical treatment of reflux oesophagitis with lansoprazole. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
26. Increased gastric acid secretion after Helicobacter pylori eradication may be a factor for developing reflux oesophagitis.
- Author
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Koike, T., Ohara, S., Sekine, H., Iijima, K., Kato, K., Toyota, T., and Shimosegawa, T.
- Subjects
- *
HELICOBACTER pylori , *GASTRIC acid , *GASTROESOPHAGEAL reflux - Abstract
Background: The role of acid secretion in reflux oesophagitis which may develop after H. pylori eradication is not well known. Aim: To investigate the participation of altered gastric acid secretion and the presence of hiatal hernia in the development of reflux oesophagitis after eradication therapy for H. pylori. Subjects and Methods: A total of 105 patients with H. pylori infection, but without reflux oesophagitis at the time of eradication therapy, were followed prospectively for 7 months after the clearance of this microorganism. Gastric acid secretion was assessed by endoscopic gastrin test, and the presence of hiatal hernia by endoscopy. Results: Reflux oesophagitis developed in 11 out of 105 (10.5%) patients when examined at 7 months after the eradication therapy. The incidence was correlated significantly with the increase in gastric acid secretion after the eradication of H. pylori, and was significantly higher in the patients with hiatal hernia (20%) than in those without it (0%). Conclusions: Increased acid secretion after H. pylori eradication is an important risk factor of reflux oesophagitis, especially in patients with hiatal hernia. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
27. Self-linearizing technique for L-band HBT power amplifier: effect of source impedance on phase distortion.
- Author
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Yamada, H., Ohara, S., Iwai, T., Yamaguchi, Y., Imanishi, K., and Joshin, K.
- Subjects
- *
PHASE shift keying , *HETEROJUNCTION bipolar transistors , *UHF power amplifiers , *MICROWAVE communication systems , *MOBILE communication systems , *ELECTRONIC linearization , *SEMICONDUCTOR devices , *POWER amplifiers , *PHASE distortion (Electronics) - Abstract
L-band power amplifiers operating with high efficiency and high linearity at a single and low supply voltage are in strong demand for mobile communication systems. This paper presents a new self-linearizing technique for power heterojunction bipolar transistors (HBTs). Utilizing the nonlinear input conductance of the device itself and setting the source impedance to the self-linearizing impedance, the phase distortion and the adjacent channel leakage power (ACP) for /spl pi//4-shift QPSK modulated signal of our InGaP/GaAs power HBTs have been greatly improved. As a result, the HBT exhibited the ACP at 50 kHz offset frequency of -49.2 dBc with a power-added efficiency (PAE) of 56% at an output power (P/sub out/) of 31 dBm under a supply voltage of 35 V. [ABSTRACT FROM AUTHOR]
- Published
- 1996
- Full Text
- View/download PDF
28. Studies of 13C-urea breath test for diagnosis of Helicobacter pylori infection in Japan.
- Author
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Ohara, S, Kato, M, Asaka, M, and Toyota, T
- Subjects
- *
GASTROINTESTINAL disease diagnosis , *HELICOBACTER disease diagnosis , *UREA metabolism , *BREATH tests , *CLINICAL trials , *COMPARATIVE studies , *GASTROINTESTINAL diseases , *HELICOBACTER diseases , *HELICOBACTER pylori , *ISOTOPES , *RESEARCH methodology , *MEDICAL cooperation , *RESEARCH , *UREASE , *EVALUATION research , *ENDOSCOPIC gastrointestinal surgery - Abstract
In recent years Helicobacter pylori infection has been implicated in the etiology of a variety of upper gastrointestinal diseases. The aim of this multi-center trial was to search for the cut-off value of the simple 13C-urea breath test (13C-UBT) for diagnosis of H. pylori infection, and to examine the sensitivity and specificity of 13C-UBT for culture, the rapid urease test (CLO test), histology, and serological tests. Two hundred and forty-eight patients participated in this study after giving their informed consent. Endoscopic biopsy specimens were taken from gastric antrum and corpus for culture (190 patients), CLO test (222 patients), and histology (98 patients). A serological test was carried out for all patients. H. pylori infection was established when culture was positive or more than two of the tests, histology, CLO test, and serological test, were positive, and non-infection status was established when the all tests more than two tests were negative. After baseline breath samples were taken, the patients (who had fasted) were given 100mg of 13C-urea in 100ml water while sitting; they washed out the mouth with water. They were then placed in the left lateral decubitus position for 5 min, and additional breath samples were taken 10, 20, 30, 45, and 60 min after urea administration, with patients in the sitting position. One hundred and sixty-five of the 248 patients were infected, 48 were not infected, and H. pylori infection status was not evaluated in 35 by endoscopic and serological tests. Breath samples at 20 min were employed to determine the cut-off value. Using the receiver operating characteristic (ROC) curve, we determined the cut-off value for a positive UBT at 2.5 delta per thousand. The sensitivities of UBT for culture, CLO test, histology, and serological test were 98.4%, 98.6%, 100.0%, and 92.5%, and the specificities were 78.8%, 82.5%, 83.3%, and 87.3%, respectively. The cut-off value of 13C-UBT for the diagnosis of H. pylori infection was 2.5 delta per thousand; this test is a simple and noninvasive method for the diagnosis of this infection and has high sensitivity and specificity. [ABSTRACT FROM AUTHOR]
- Published
- 1998
- Full Text
- View/download PDF
29. Ultrasonic splicing of polymer optical fibres.
- Author
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Mizuno, Y., Ohara, S., Hayashi, N., and Nakamura, K.
- Abstract
A new method of splicing polymer optical fibres by irradiation of megahertz ultrasonic waves is demonstrated. The lowest connection loss of 1.5 dB is obtained at 2 MHz, and a high mechanical strength of 59 N (close to the strength of the base polymer) is achieved at 1 MHz. It is shown that the loss and strength are in a trade‐off relationship, and that the duration of ultrasonic irradiation has a certain optimal value of ∼1 s. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
30. Collision synthesis of unique carbon nanomaterials inspired by the Allende meteorite
- Author
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Ohara, S., Tan, Z., Noma, J., Hanaichi, T., Sato, K., and Abe, H.
- Subjects
- *
ALLENDE meteorite , *CARBON nanotubes , *MECHANICAL alloying , *STEEL , *SURFACE chemistry , *HIGH temperatures , *MOLECULAR structure - Abstract
Abstract: A simple shock event approach inspired by the Allende meteorite to produce sophisticated carbon nanomaterials is reported. It is demonstrated that unique carbon nanostructures, including carbon nanotubes, carbon onions, and new carbon nanorings are synthesized by high-speed ball-milling of steel balls. The carbon nanorings have diameter of several tens of nanometers. It is considered that the carbon nanomaterials are formed from around the surface of steel balls under local high temperatures induced by the collision energy in ball-milling process. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
31. Pressure effect on magnetic transitions in heavy-fermion antiferromagnet Ce2RhIn8
- Author
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Ohara, S., Watanabe, R., Suzuki, T., and Sakamoto, I.
- Subjects
- *
ANTIFERROMAGNETISM , *MAGNETIC fields , *MAGNETIZATION , *PHASE diagrams - Abstract
Abstract: Detailed magnetization measurements under pressure have been performed on tetragonal heavy-fermion antiferromagnet Ce2RhIn8 single crystals. From the results of field and temperature dependences of the magnetic transitions, we construct the magnetic field–temperature phase diagrams of Ce2RhIn8 at several pressures up to 6kbar, in magnetic fields up to 55kOe between 1.8 and 3K. The antiferromagnetic long-range order of Ce2RhIn8 is suppressed by pressure. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
32. Twenty-Year Follow-Up of a Patient with Subacute Sclerosing Panencephalitis.
- Author
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Hashimoto, T., Ohara, S., Yanagisawa, N., and Ikeda, S.
- Subjects
- *
SUBACUTE sclerosing panencephalitis , *DIFFUSE cerebral sclerosis , *ENCEPHALITIS , *MEASLES complications - Abstract
Discusses a case of a patient with subacute sclerosing panecephalitis after 20 years. Case history; Treatment options; Course of clinical picture.
- Published
- 2005
- Full Text
- View/download PDF
33. Ultrasonic splicing of polymer optical fibres.
- Author
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Mizuno, Y., Ohara, S., Hayashi, N., and Nakamura, K.
- Subjects
- *
OPTICAL fiber joints , *ULTRASONIC waves , *OPTICAL fiber networks , *ULTRASONIC welding , *OPTICAL communications - Abstract
A new method of splicing polymer optical fibres by irradiation of megahertz ultrasonic waves is demonstrated. The lowest connection loss of 1.5 dB is obtained at 2 MHz, and a high mechanical strength of 59 N (close to the strength of the base polymer) is achieved at 1 MHz. It is shown that the loss and strength are in a trade-off relationship, and that the duration of ultrasonic irradiation has a certain optimal value of ~1 s. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
34. Application of sputtered SiO2 insulator to Nb/AlOx/Nb Josephson junctions.
- Author
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Hoko, H., Imamura, T., Ohara, S., and Hasuo, S.
- Subjects
- *
SILICA , *JOSEPHSON effect , *BREAKDOWN voltage , *NIOBIUM - Abstract
Describes the evaluation of the sputtered silicon dioxide as an insulator available in all niobium (Nb) Josephson circuits. Insulation characteristics of the silicon-oxygen compound; Quality of the sputtered silicon dioxide for infrared absorption and the breakdown voltage; Step coverage at the underlying Nb electrode edge.
- Published
- 1987
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35. 254 DSC2 IS A NEW IMMUNOHISTOCHEMICAL MARKER INDICATIVE OF SQUAMOUS CELL CARCINOMA COMPONENT IN URINARY BLADDER CANCER AND A VALUABLE PROGNOSTIC FACTOR
- Author
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Hayashi, T., Ohara, S., Shoji, K., Teishima, J., Anami, K., Sakamoto, N., Sentani, K., Oue, N., Yasui, W., and Matsubara, A.
- Published
- 2011
- Full Text
- View/download PDF
36. Non-fermi-liquid behavior in electronic specific heat of heavy-fermion superconductor Ce2CoIn8
- Author
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Yamashita, T., Ohara, S., Aoki, Y., Miyazaki, R., and Sakamoto, I.
- Subjects
- *
FERMI liquid theory , *SPECIFIC heat , *FERMIONS , *SUPERCONDUCTORS , *INDIUM compounds , *TRANSITION temperature , *MAGNETIC fields , *ANTIFERROMAGNETISM - Abstract
Abstract: Ce2CoIn8 is a heavy-fermion superconductor with the transition temperature of . We have measured the low temperature specific heat under high magnetic fields on pure powder single crystals of Ce2CoIn8. Below 0.6K, the electronic specific heat divided by temperature increases with decreasing temperature at zero field, indicating a superconducting transition. At around , a broad maximum appears in and it shifts to lower temperatures with increasing field, indicating the existence of antiferromagnetic (AF) correlations. In fields, a dependence in observed above develops and finally it covers the measured temperature range of under H =80 kOe. Therefore, this non-fermi-liquid behavior is attributable to a quantum critical point associated with the antiferromagnetic correlations. The present observation indicates that the heavy-fermion superconductivity in Ce2CoIn8 is mediated by the AF correlations. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
37. 218 TRENDS IN PERCEPTION OF MALE ERECTILE DYSFUNCTION DRUGS AMONG WOMEN IN THE GENERAL POPULATION IN JAPAN
- Author
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Mila, K., Ohara, S., Inoue, Y., Hasegawa, Y., Seki, M., Kato, M., Teishima, J., Matsubara, A., and Usui, T.
- Published
- 2007
- Full Text
- View/download PDF
38. Surface ligand assisted valence change in ceria nanocrystals.
- Author
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J. Zhang, Naka, T., Ohara, S., Kaneko, K., Trevethan, T., Shluger, A., and Adschiri, T.
- Subjects
- *
CERIUM oxide crystals , *LIGANDS (Chemistry) , *X-ray spectroscopy , *ELECTRON energy loss spectroscopy , *OLEIC acid - Abstract
In this report, we used x-ray absorption, electron energy-loss, and magnetic analyses to demonstrate the effect of modification of ceria (CeO2-δ) nanocrystals with a particle size D = 3.5-14 nm by oleic acid surface ligands. We observe a shift of the electronic state of the cerium ions from tetra to trivalent state as the surface density of the ligand molecules is increased. The valence state of cerium in the nanocrystal is strongly correlated with the number of ligand molecules bound to the surface of the ceria nanocrystals. One oxygen vacancy is stabilized by 5-6 ligand molecules bound on a CeO2-δ nanocrystal. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
39. Spatial attention to thermal pain stimuli in subjects with visual spatial hemi-neglect: Extinction, mislocalization and misidentification of stimulus modality
- Author
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Liu, C.C., Veldhuijzen, D.S., Ohara, S., Winberry, J., Greenspan, J.D., and Lenz, F.A.
- Subjects
- *
BRAIN stimulation , *BRAIN function localization , *PAIN perception , *STATISTICAL hypothesis testing , *EXTINCTION (Psychology) , *CONTROL groups - Abstract
Abstract: One approach to the study of disordered spatial attention is to carry out tests of extinction, in which stimuli are detected on the left when they are presented on the left alone, but not when both sides are stimulated simultaneously in a dual simultaneous stimulation (DSS) protocol. Extinction has been documented for multiple sensory modalities, but not for thermal pain stimuli, to our knowledge. We now test the hypothesis that subjects with visual spatial neglect (hemi-neglect) will have alterations in thermal pain sensation which are related to abnormal spatial attention. The results demonstrate that thermal pain extinction of hot and cold pain stimuli occurs in a proportion of subjects with hemi-neglect. In the subjects with visual spatial hemi-neglect but without thermal pain extinction, the sensation of the thermal pain stimulus on the affected (left) side was not extinguished but was often localized to the unaffected (right) side, and the submodality of the stimulus (cold or hot) was often misidentified. Ratios indicating the magnitude of extinction, mislocalization and misidentification were significantly larger on the left side of subjects with visual spatial neglect than in healthy controls or in controls with stroke but without hemineglect. The proportion of subjects with thermal pain extinction, mislocalization, or misidentification was significantly higher in subjects with hemi-neglect than those in either control group. These results demonstrate that disordered attention exerts a powerful effect upon the perception of both the location and the quality of thermal pain stimuli. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
40. Relationship of smoking and smoking cessation with number of teeth present: JPHC Oral Health Study.
- Author
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Yanagisawa, T, Marugame, T, Ohara, S, Inoue, M, Tsugane, S, and Kawaguchi, Y
- Subjects
- *
SMOKING , *SMOKING cessation , *TOBACCO use , *DENTAL pathology , *ORAL diseases , *ORAL medicine - Abstract
Background: Smoking is associated with the number of teeth. The purpose of this study was to determine the relationship of number of teeth with smoking and smoking cessation. Methods: Subjects included 547 males aged between 55 and 75 years. Oral examinations were conducted in 2005. Smoking status information was collected from questionnaire surveys conducted in 1990, 1995, 2000, and 2005. The relationship between having more than eight missing teeth and smoking status was estimated with adjusted odds ratio. Results: Comparing with never smokers, odds ratios of having more than eight missing teeth among current and former smokers were 1.96 and 1.86, respectively. The odds ratios in those who had stopped smoking for ≤10 years was 3.02, and for those who had ceased smoking for 11–20 years was 2.66. In those who stopped smoking for 21 years or more, there was no increase in the odds ratio. Conclusion: Smoking had a positive association with the number of missing teeth and smoking cessation is beneficial for maintaining teeth. The odds of having more than eight missing teeth in those who had never smoked was equal to that of individuals who reported that they had stopped smoking for 21 years or more. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
41. Fabrication technology for lead-alloy Josephson devices for high-density integrated circuits.
- Author
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Imamura, T., Hoko, H., Tamura, H., Yoshida, A., Suzuki, H., Morohashi, S., Ohara, S., Hasuo, S., and Yamaoka, T.
- Subjects
- *
LEAD alloys , *JOSEPHSON junctions - Abstract
Evaluates the combined technology for fabricating lead-alloy Josephson devices. Description of fabrication techniques for the lead-alloy devices; Characteristics of each element in the circuits; Information on the 8-kbit memory cell arrays.
- Published
- 1986
- Full Text
- View/download PDF
42. Axonal TDP-43 aggregates in sporadic amyotrophic lateral sclerosis.
- Author
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Onozato, T., Nakahara, A., Suzuki‐Kouyama, E., Hineno, A., Yasude, T., Nakamura, T., Yahikozawa, H., Watanabe, M., Kayanuma, K., Makishita, H., Ohara, S., Hashimoto, T., Higuchi, K., Sakai, T., Asano, K., Kanno, H., Nakayama, J., and Oyanagi, K.
- Subjects
- *
DNA-binding proteins , *AMYOTROPHIC lateral sclerosis , *AXONS , *CYTOPLASMIC filaments , *SYNAPSES , *MOTOR neurons , *HYPOGLOSSAL nerve - Abstract
Aims Axonal aggregates of phosphorylated (p-) transactive response DNA-binding protein 43 kDa (TDP-43) in sporadic amyotrophic lateral sclerosis (sALS) were examined in relation to propagation of the protein in the nervous system. Methods Brains and spinal cords of Japanese patients with sALS and control subjects were examined immunohistochemically using formalin-fixed paraffin-embedded specimens with special reference to the topographical distribution, microscopic features, presynaptic aggregates, and correlation between the aggregates in axons and the clinical course. Results (i) Aggregates of p-TDP-43 were frequently present in axons of the hypoglossal and facial nerve fibres and the spinal anterior horn cells. (ii) Aggregates of p-TDP-43 in the axons showed two characteristic microscopic features - dash-like granuloreticular aggregates (GRAs) and massive aggregates (MAs). (iii) MAs were surrounded by p-neurofilaments, but p-neurofilament immunnoreactivity decreased at the inside of axons with GRAs. (iv) Patients showing MAs and GRAs had a relatively shorter clinical course than patients without the aggregates. (v) Some neurones in the red nucleus in patients were surrounded by synapses containing p- and p-independent (i)-TDP-43, and almost all neurones had lost their nuclear TDP-43 immunoreactivity; 17% of those neurones in the red nucleus also had TDP-43-immunopositive neuronal cytoplasmic inclusions, but no postsynaptic p-TDP-43 deposition was evident. Conclusions There are two types of axonal p-TDP-43 aggregates, MAs and GRAs, located predominantly in the facial and hypoglossal nuclei and anterior horn cells. These aggregates may influence the function of neurones, and presynaptic aggregates of the protein induce loss of p-i-TDP-43 in the nuclei of postsynaptic neurones. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
43. Pressure-Induced Valence Crossover and Novel Metamagnetic Behavior near the Antiferromagnetic Quantum Phase Transition of YbNi3Ga9.
- Author
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Matsubayashi, K., Hirayama, T., Yamashita, T., Ohara, S., Kawamura, N., Mizumaki, M., Ishimatsu, N., Watanabe, S., Kitagawa, K., and Uwatoko, Y.
- Subjects
- *
ELECTRICAL resistivity , *MAGNETIC susceptibility , *X-ray spectroscopy , *VALENCE fluctuations , *ANTIFERROMAGNETIC resonance - Abstract
We report electrical resistivity, ac magnetic susceptibility, and x-ray absorption spectroscopy measurements of intermediate valence YbNi3Ga9under pressure and magnetic field. We have revealed a characteristic pressure-induced Yb valence crossover within the temperature-pressure phase diagram, and a first-order metamagnetic transition is found below Pc ∼ 9 GPa where the system undergoes a pressure-induced antiferromagnetic transition. As a possible origin of the metamagnetic behavior, a critical valence fluctuation emerging near the critical point of the first-order valence transition is discussed on the basis of the temperature-field-pressure phase diagram. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
44. Simultaneous, parallel and multiple EAS events due to Gerasimova-Zatsepin effect in LAAS experiments.
- Author
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Iyono, A., Matsumoto, H., Okei, K., Tsuji, S., Ohara, S., Ochi, N., Konishi, T., Takahashi, N., Yamamoto, I., and Nakatsuka, T.
- Subjects
- *
COSMIC ray showers , *ELECTROMAGNETIC waves , *HIGH energy astronomy observatories , *PHOTONUCLEAR reactions , *HEAVY nuclei , *PHOTONS - Abstract
To study the ultra-high energy cosmic ray composition by making use of the GZ scenario, Large Area Air Shower (LAAS) experiments had been started in 1996 by the collaboration of 7 institutes in Japan. We present here some results of LAAS observations on the GZ event search during the data period from 1996 to January 2007. A brief profile of the potential of LAAS EAS array is also presented. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
45. P2–082THE MODIFIED PNA-LNA PCR CLAMP METHOD FOR THE DETECTION OF EGFR MUTATIONS IN NON-SMALL CELL LUNG CANCER.
- Author
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Tanai, C., Ushijima, T., Ohara, S., Tanaka, Y., Noda, H., Usui, K., and Horiuchi, H.
- Subjects
- *
EPIDERMAL growth factor receptors , *POLYMERASE chain reaction , *LUNG cancer diagnosis , *GENETIC mutation , *ERLOTINIB , *ADENOCARCINOMA , *RETROSPECTIVE studies - Published
- 2013
- Full Text
- View/download PDF
46. Inhomogeneous magnetic phase in Co–Al–O spinel nanocrystals.
- Author
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Sato, K., Naka, T., Nakane, T., Rangappa, D., Takami, S., Ohara, S., and Adschiri, T.
- Subjects
- *
COBALT alloys , *INHOMOGENEOUS materials , *MAGNETIC transitions , *MAGNETIC properties , *NANOCRYSTALS , *CRYSTALLOGRAPHY , *X-ray diffraction - Abstract
Abstract: We report on the crystallographic structure and magnetism of 5-nm Co–Al–O spinel nanocrystals synthesized under supercritical hydrothermal conditions. Structural examination using powder X-ray diffraction and chemical analysis showed the composition of the sample to be Co0.47Al2.36O4 rather than the stoichiometric composition of CoAl2O4. The site occupancy of Co on the A-site forming the diamond lattice was 0.47, which is slightly larger than the site percolation limit. Magnetization measurements showed that magnetic clusters emerged below 40K. At temperatures below 40K, a Griffiths-phase-like inhomogeneous state appeared in the sample in which magnetic clusters and paramagnetic spins coexisted. The dc-paramagnetic and ac-susceptibilities exhibited an anomaly below 7K. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
47. Structural, morphological and luminescence properties of nanocrystalline up-converting Y1.89Yb0.1Er0.01O3 phosphor particles synthesized through aerosol route.
- Author
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Lojpur, V., Mancic, L., Rabanal, M.E., Dramicanin, M.D., Tan, Z., Hashishin, T., Ohara, S., and Milosevic, O.
- Subjects
- *
PHOSPHORS , *NANOCRYSTALS , *LUMINESCENCE , *CRYSTAL morphology , *CHEMICAL synthesis , *TEMPERATURE effect - Abstract
Highlights: [•] The Y1.89Yb0.1Er0.01O3 phosphor particles are synthesized via aerosol route. [•] We report influence of process parameters on the particle structure and morphology. [•] Spherical, submicronic size and nano-crystalline particle morphology are confirmed. [•] The particles show improved luminescence properties and decay time. [•] Synthesized powders exhibit the temperature dependant up-conversion emission. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
48. Aerosol route as a feasible bottom-up chemical approach for up-converting phosphor particles processing.
- Author
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Dugandžić, I., Lojpur, V., Mančić, L., Dramićanin, M.D., Rabanal, M.E., Hashishin, T., Tan, Z., Ohara, S., and Milošević, O.
- Subjects
- *
PHOSPHORS , *AEROSOLS , *RARE earth ions , *CRYSTAL structure , *CRYSTAL morphology , *EMISSION spectroscopy - Abstract
Highlights: [•] Aerosol route is applied for up-conversion Y2O3:Yb3+, Er3+ nanophosphors processing. [•] Droplet-to-particle conversion and aerosol transport properties are followed. [•] Particles structural, morphological and functional properties are analysed. [•] Particles compositional uniformity and nano-clustered inner structure are confirmed. [•] Emission spectra and improved decay times are correlated with processing parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
49. Activation of the aryl hydrocarbon receptor represses mammosphere formation in MCF-7 cells.
- Author
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Zhao S, Kanno Y, Nakayama M, Makimura M, Ohara S, and Inouye Y
- Published
- 2012
50. Relationship between the localization of fibroblast growth factor 9 in prostate cancer cells and postoperative recurrence.
- Author
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Teishima, J, Shoji, K, Hayashi, T, Miyamoto, K, Ohara, S, and Matsubara, A
- Subjects
- *
FIBROBLAST growth factors , *CELL proliferation , *PROSTATECTOMY , *IMMUNOHISTOCHEMISTRY , *CELLS - Abstract
Background:Fibroblast growth factor 9 (FGF9) enhances cell proliferation and invasiveness in several malignant diseases. The aim of the present study is to investigate the role of FGF9 in postoperative recurrence after radical prostatectomy.Methods:Cell viability and invasion of LNCaP cells were assessed using MTT assay and Matrigel invasion assay, respectively, in the presence or absence of treatment with recombinant FGF9. Tissues obtained during a radical prostatectomy in 133 male patients were immunohistochemically stained using anti-FGF9 antibody.Results:Cell viability and invasion of LNCaP was significantly enhanced by treatment with recombinant FGF9. Immunohistochemical staining detected FGF9-positive cells in 20 samples. The prevalence of FGF9-positive cells in cases with a Gleason score of 8 or higher was 34.2%, which was significantly higher than that in those with Gleason scores of 7 or lower (7.3%, P=0.0003), respectively. The 3-year biochemical relapse-free survival rate was 17.5% in cases with FGF9-positive cells, which was significantly lower than that in cases in which FGF9-positive cells were not detectable (75.5%, P<0.0001).Conclusions:These results indicate that FGF9 can stimulate proliferation and invasion in prostate cancer cells, thus FGF9 could be a candidate of a predictive factor for recurrence after radical prostatectomy. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
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