In the past Makoto Takahashi has collaborated on articles with Susumu Sakata and Jyong-Chyul Cyong. One of their most recent publications is Research paperOrigin of light hydrocarbons from volcanic rocks in the “Green Tuff” region of northeast Japan: Biogenic versus magmatic. Which was published in journal Chemical Geology.

More information about Makoto Takahashi research including statistics on their citations can be found on their Copernicus Academic profile page.

Makoto Takahashi's Articles: (32)

Research paperOrigin of light hydrocarbons from volcanic rocks in the “Green Tuff” region of northeast Japan: Biogenic versus magmatic

AbstractGeochemical analyses were carried out to assess the origin of light hydrocarbons in natural gases derived from volcanic rocks in the “Green Tuff” region of northeast Japan, whose high He isotope ratios have suggested a possible magma gas component. Biogenic steroid hydrocarbons were detected unambiguously in the oils associated with the natural gases, and they showed similar molecular distributions from C27 to C29 as those of the oils accumulated in the adjacent sedimentary rocks. Correlation of C1(C2 + C3)vs. δ13CCH4 for the light hydrocarbons indicated that they are thermocatalytic products from sedimentary organic matter. On the assumption that the magmatic CH43He ratio is 106, no more than 0.1% of the total methane can be attributed to a magmatic origin. The remaining methane is likely to have migrated from the adjacent sedimentary layers.

Identification of guanosine 3′:5′-monophosphate in the fruit of Zizyphus jujuba

AbstractEvidence is presented here confirming the identification of guanosine 3′: 5′-monophosphate (c GMP) in the tissue of higher plants. The c GMP activity detected in fruits of Zizyphus jujuba was separated from the c AMP activity also present. The separated sample was extensively purified by Bio-Rad AG 1 × 4 and aluminium oxide CC, and by TLC. The purified sample showed the same physicochemical properties as authentic c GMP by TLC using different solvents and by UV spectroscopy, and was decomposable by cyclic nucleotide-specific phosphodiesterase. The identification was further supported by HPLC. The amount of c GMP present increases 90-fold during fruit ripening.

The composition and conductivity of electrodeposited BiTe alloy films

AbstractMeasurements of electric conductivity and composition were performed on BiTe alloy films electrodeposited from an aqueous solution containing 1.50 mM TeO2 and various concentrations of Bi(NO3)3. X-ray diffraction measurements showed that Bi2Te3 intermetallic compound was produced by the electrodeposition. Auger electron spectroscopy measurements showed that the Bi/Te ratio of the films increased with the increasing Bi(NO3)3 concentration in electrolyte solutions. The relation between the Bi(NO3)3 concentration in electrolyte solutions and conductivity was volcano-like, and films deposited in 1.50 mM Bi(NO3)3 showed maximum conductivity.

ArticleSpinocerebellar Ataxia Type 31 Is Associated with “Inserted” Penta-Nucleotide Repeats Containing (TGGAA)n

Spinocerebellar ataxia type 31 (SCA31) is an adult-onset autosomal-dominant neurodegenerative disorder showing progressive cerebellar ataxia mainly affecting Purkinje cells. The SCA31 critical region was tracked down to a 900 kb interval in chromosome 16q22.1, where the disease shows a strong founder effect. By performing comprehensive Southern blot analysis and BAC- and fosmid-based sequencing, we isolated two genetic changes segregating with SCA31. One was a single-nucleotide change in an intron of the thymidine kinase 2 gene (TK2). However, this did not appear to affect splicing or expression patterns. The other was an insertion, from 2.5–3.8 kb long, consisting of complex penta-nucleotide repeats including a long (TGGAA)n stretch. In controls, shorter (1.5–2.0 kb) insertions lacking (TGGAA)n were found only rarely. The SCA31 repeat insertion's length inversely correlated with patient age of onset, and an expansion was documented in a single family showing anticipation. The repeat insertion was located in introns of TK2 and BEAN (brain expressed, associated with Nedd4) expressed in the brain and formed RNA foci in the nuclei of patients' Purkinje cells. An electrophoretic mobility-shift assay showed that essential splicing factors, serine/arginine-rich splicing factors SFRS1 and SFRS9, bind to (UGGAA)n in vitro. Because (TGGAA)n is a characteristic sequence of paracentromeric heterochromatin, we speculate that the insertion might have originated from heterochromatin. SCA31 is important because it exemplifies human diseases associated with “inserted” microsatellite repeats that can expand through transmission. Our finding suggests that the ectopic microsatellite repeat, when transcribed, might cause a disease involving the essential splicing factors.

Protonic conduction model in glasses – A quadratic relation between conductivity and proton concentration

AbstractProton conductivity in glasses has been known to be proportional to the square of the concentration of mobile protons of the glasses, but the mechanisms of this quadratic relation are not elucidated yet. A model for the quadratic relation between conductivity and proton concentration in glasses is presented from a view point regarding the proton conduction as a quasi-chemical reaction.

Separation of copolymers using high-performance liquid chromatography with polymeric stationary phase and liquefied carbon dioxide as adsorption promoting solvent

AbstractChromatographic separation of copolymers depending on the chemical composition was studied by a solvent gradient method using liquefied carbon dioxide (CO2) as an adsorption promoting solvent. As the high polar stationary phase, non-bonded silica gel, crosslinked acrylamide (AA) gel and crosslinked acrylonitrile (AN) gel were utilized. All columns showed the typical normal phase type of adsorption. Polymeric stationary phases showed the higher sample recovery for styrene–methyl methacrylate (St–MMAs) copolymers, indicating suitability for quantitative analyses. The separations of butyl methacrylate (BMA)–methyl methacrylate, and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (FBMA)–methy methacrylate copolymers were also carried out, and the latter copolymers were separated based on the CO2-philicity with acrylonitrile column.

Occurrence of actinlike microfilaments in the outer root sheath cells of the hair follicle: a possible role of a cytoskeleton

Broad bundles of actinlike microfilaments are found in the basal cells of the outer root sheath of the hair follicle. The filaments react specifically with heavy meromyosin to form a fuzzy structure, and disappear from the cells after the actin depolymerization treatment. An array of the filament bundles alters along with the cell shape changes of the basal cells. In the flattened cells of the hair follicle bulb, the bundles appear to run parallel to the long axis of the cells, and are present in the basal cytoplasm. In the cuboidal cells of the suprabulbar and the more superficial portion of the follicle, the bundles are perpendicular to the basal plasma membrane, and are disposed mainly in the basal cytoplasm. The microfilaments are associated with the basal plasma membrane directly or via insertion into the plaque of the membrane, where filamentous or amorphous materials link the membrane and the basal lamina. In vitro treatment of cytochalasin B for up to 8 hr causes no visible change in the distribution pattern of the bundles nor abnormal changes in the cell shape. Thus, the actinlike microfilament bundles appear to provide a cytoskeletal system reponsible for the maintenance of the cell shape change, since they are disposed in the direction and area in which a maintenance force for the cell shape change may be required, and other cytoskeletal systems of the cells such as microtubules and tonofilament—desmosome complexes are poorly developed, and no hemidesmosomes are present in the cells.

Preparation and characterization of high-quality stoichiometric LiNbO3 thick films prepared by the sol–gel method

AbstractStoichiometric lithium niobate (SLN) thick films were deposited on z-cut LiNbO3 using the sol–gel method from a precursor solution containing various polyvinyl alcohol (PVA) concentrations and their characteristics were investigated. The film thickness increases linearly and the roughness decreases with the increase in PVA concentration. The refractive indexes of the films prepared with PVA were n0=2.28±0.02 and ne=2.19±0.02 at a wavelength of 632.8 nm. The transmission loss was 0.61±0.05 dB/cm

Original ArticlesIsolated Trigeminal Nerve Metastases from Breast Cancer: An Unusual Cause of Trigeminal Mononeuropathy

AbstractBackgroundMononeuropathy of a cranial nerve caused by brain metastases rarely occurs in patients with a malignant neoplasm. Even after the development of computed tomography (CT) and magnetic resonance imaging (MRI), few cases of brain metastases resulting in trigeminal mononeuropathy have been reported. We report a case of trigeminal mononeuropathy caused by a brain metastases that was detected on CT and MRI preoperatively, and was successfully treated by microsurgery and radiation.Case DescriptionA 49-year-old woman with a history of breast cancer complained of right facial pain. CT and MRI revealed a brain tumor in the right Meckel’s cave and cerebellopontine angle. She underwent surgery, and the diagnosis was metastatic breast cancer. No recurrence was detected on MRI performed 2 years after the resection and radiation of the tumor.ConclusionsMost of the reported cases of brain metastases causing a mononeuropathy occurred before the availability of CT; the mononeuropathy was diagnosed by neurologic or postmortem examination. Even after the development of CT and MRI, few cases of brain metastases resulting in trigeminal mononeuropathy have been reported. If such patients do not manifest symptoms of brain metastases other than the mononeuropathy, it is difficult to make the correct diagnosis without CT and MRI. Physicians must be aware of mononeuropathy as an uncommon presenting symptom of brain metastases.

News impact curve for stochastic volatility models

Highlights•We propose two news impact curves for stochastic volatility models.•We use a rejection sampling method to compute the conditional density of the (log) volatility.•We show a scatter plot of the return and the volatility using the Markov chain Monte Carlo scheme.

Estimating stochastic volatility models using daily returns and realized volatility simultaneously

AbstractRealized volatility, which is the sum of squared intraday returns over a certain interval such as a day, has recently attracted the attention of financial economists and econometricians as an accurate measure of the true volatility. In the real market, however, the presence of non-trading hours and market microstructure noise in transaction prices may cause bias in the realized volatility. On the other hand, daily returns are less subject to noise and therefore may provide additional information on the true volatility. From this point of view, modeling realized volatility and daily returns simultaneously based on the well-known stochastic volatility model is proposed. Empirical studies using intraday data of Tokyo stock price index show that this model can estimate realized volatility biases and parameters simultaneously. The Bayesian approach is taken and an efficient sampling algorithm is proposed to implement the Markov chain Monte Carlo method for our simultaneous model. The result of the model comparison between the simultaneous models using both naive and scaled realized volatilities indicates that the effect of non-trading hours is more essential than that of microstructure noise and that asymmetry is crucial in stochastic volatility models. The proposed Bayesian approach provides an estimate of the entire conditional predictive distribution of returns under consideration of the uncertainty in the estimation of both biases and parameters. Hence common risk measures, such as value-at-risk and expected shortfall, can be easily estimated.

Volatility and quantile forecasts by realized stochastic volatility models with generalized hyperbolic distribution

AbstractThe predictive performance of the realized stochastic volatility model of Takahashi et al. (2009), which incorporates the asymmetric stochastic volatility model with the realized volatility, is investigated. Considering the well-known characteristics of financial returns, namely heavy tails and skewness, the model is extended by employing a wider class distribution, the generalized hyperbolic skew Student’s t-distribution, for financial returns. Using the Bayesian estimation scheme via a Markov chain Monte Carlo method, the model enables us to estimate the parameters in the return distribution and in the model jointly. It also makes it possible to forecast the volatility and return quantiles by sampling from their posterior distributions jointly. The model is applied to quantile forecasts of financial returns such as value-at-risk and expected shortfall, as well as to volatility forecasts, and the forecasts are evaluated using a range of tests and performance measures. The empirical results using the US and Japanese stock indices, the Dow Jones Industrial Average and Nikkei 225, show that the extended model improves the volatility and quantile forecasts, especially in some volatile periods.

An approach for homogeneous carbon nanotube dispersion in Al matrix composites

Highlights•A novel approach was developed on the hot topic of carbon nanotube dispersion in composites.•Homogeneous carbon nanotube dispersion with a large aspect ratio and small damage was obtained.•Strength enhancement by carbon nanotube addition was examined by load transfer mechanism in Al matrix composites.•Al4C3 nano-rods were detected and helpful for load transfer in carbon nanotube/Al composites.

Antioxidant activity of sugarcane molasses against 2,2′-azobis(2-amidinopropane) dihydrochloride-induced peroxyl radicals

Highlights•Sugarcane molasses constituents effectively scavenge AAPH-induced peroxyl radicals.•Antioxidative fractions were evaluated via chemical, cellular, and DNA approaches.•The range of ORAC value is 4399–6266 μmol TE/g, and EC50 for CAA is 3.7–5.9 μg/ml.•Two fractions protect against oxidative DNA damage as potent as gallic acid.•Phenolic constituents were identified in the sugarcane molasses fractions.

Original ArticleA mutation spectrum that includes GNAS, KRAS and TP53 may be shared by mucinous neoplasms of the appendix

AbstractAppendiceal mucinous tumors (AMTs) are classified as low-grade appendiceal mucinous neoplasms (LAMNs) or mucinous adenocarcinomas (MACs), although their carcinogenesis is not well understood. As somatic activating mutations of GNAS are considered to be characteristic of LAMNs while TP53 mutations have been shown to be specific to MACs, MACs are unlikely to result from transformation of LAMNs. However, emerging evidence also shows the presence of GNAS mutations in MACs. We examined 16 AMTs (11 LAMNs and 5 MACs) for genetic alterations of GNAS, KRAS, BRAF, TP53, CTNNB1, and TERT promoter in order to elucidate the possibility of a shared genetic background in the two tumor types. Extensive histological examination revealed the presence of a low-grade component in all cases of MAC. GNAS mutations were detected in two LAMNs and in one MAC, although the GNAS mutation in this MAC was a nonsense mutation (Q227X) expected not to be activating mutation. TP53 mutations were detected in three LAMNs; they were frequently detected in MACs. KRAS mutations were detected in three LAMNs and three MACs, and CTNNB1 mutations were detected in two LAMNs. KRAS mutation and activating mutation of GNAS occurred exclusively in AMTs. BRAF and TERT mutations were not detected. Overexpression of p53 was observed in only two MACs, and p53 immunostaining clearly discriminated the high-grade lesion from a low-grade component in one. These findings suggest that p53 overexpression plays an important role in the carcinogenesis of AMTs and that, in addition to mutations of GNAS, KRAS and TP53 alterations might be shared by AMTs, thus providing evidence for the possible progression of LAMNs to MAC.

Sponge Ni catalyst with high activity in CO2 methanation

Highlights•CO2 methanation was carried out with sponge Ni and NiO/CeO2.•Sponge Ni was active in CO2 methanation under a high space velocity.•The high activity was derived from the crystal defects of fcc-Ni in the sponge Ni.

Recent distribution changes affect geographic clines in genetic diversity and structure of Pinus densiflora natural populations in Japan

Highlights•Genetic diversity and structure of Pinus densiflora populations was examined.•Allelic richness was significantly lower in both northern and eastern populations.•Recent bottleneck was inferred more frequently in northern and eastern populations.•Northeastern cluster showed higher F value than the western and central clusters.•Strong genetic drift through rapid expansion in northeastern population was indicated.

Identification of the opener and closer of the pharyngoesophagus in laryngectomees

AbstractBackground: In esophageal and tracheoesophageal speakers, the neoglottis acts not only as the orifice of the digestive tract but also as the airway and the voice source. The opening and closing mechanism is thought to be essential for these functions. It is not known, however, whether there is any active muscular control of neoglottal opening and closing. Examinations have been carried out to find the physiological background of the opening and closing of the neoglottis. In this paper, we present our findings of the opening and closing mechanism of the neoglottis and discuss them with reviewing the previous studies.Subjects and methods: Subjects were volunteer esophageal speakers. Neoglottal width, EMG of the inferior pharyngeal constrictor (IPC) and that of the geniohyoid muscle (GH) were recorded simultaneously during swallowing and air intake for esophageal speech.Results: At rest, the neoglottis was closed by the mucosal protrusion in the posterior wall of the pharyngoesophagus. During swallowing, the neoglottis was widely opened. Traction of the anterior pharyngeal wall anteriorly by the GH and reciprocal suppression of the IPC activity was thought to be the mechanism of the neoglottal opening in this case. However, such simple reciprocity was not observed during air intake, although transient opening of the neoglottis was commonly observed. The GH showed increased activity at neoglottal opening as it did during swallowing. The IPC was, on the other hand, continuously activated, and no significant suppression was observed. During air intake, the muscle is assumed to play a role in maintaining the shape and tension of the posterior mucosal protrusion which acts as a voice source in subsequent phonation.Conclusions: The GH and the IPC were found to open and close the neoglottis, respectively. Their activities were not always clearly reciprocal in the various functions of the neoglottis.

Neural Responses to Electrical Stimulation of the Cochlea in Guinea Pigs

A special bridge circuit was constructed to compensate stimulus artifact to determine the effects of an alternating current (AC) in the range of 3 to 20 kHz and direct current (DC) stimulation on the activity of cochlear nerve fibers. When AC and DC stimulation of the same fiber were compared, a greater current intensity was required to change the spike rate with AC stimulation than DC stimulation. While positive DC stimulation reduced activity, negative DC stimulation increased the spike rate. AC stimuli excited fibers in a manner similar to that observed with negative DC stimulation. Thresholds increased with stimulus frequency, suggesting that the effects of AC stimulation on the discharge rate are independent of the CF (characteristic frequency) of a fiber. The effects of short-time AC and DC stimulation on cochlear fiber activity lasted only during the stimulation, and the spontaneous activity did not significantly differ before and after electrical stimulation.

Acetabular reconstruction using a Kerboull-type acetabular reinforcement device and hydroxyapatite granules: A 3- to 8-year follow-up study1

AbstractBetween 1993 and 1997, 21 consecutive revision total hip arthroplasties were performed in 20 patients using hydroxyapatite (HA) granules supported by a Kerboull-type reinforcement acetabular device. Acetabular bone loss according to the American Academy of Orthopaedic Surgeons (AAOS) system was type II for 5 hips and type III for 16 hips. Autografts were used to reconstruct the major segmental defects in 6 hips. The mean follow-up period of the series was 5 years and 4 months. No migration of the socket was seen. Slight inclination of the acetabular device was noted in 1 hip without functional deficits. The mean preoperative Merle d’Aubigné hip functional score was 9.3 versus 15.4 at the latest follow-up evaluation. Acetabular reconstruction with HA granules and a Kerboull-type acetabular device provided satisfactory 3- to 8-year clinical and radiographic results.

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