131 research outputs found

    Precise Measurement of Helium Isotopes in Groundwater

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    In order to estimate the origin and resident time of groundwater, the helium isotope ratio (3He/4He) should be analyzed precisely. We present here experimental details of an analytical system including a helium purification vacuum line, the purification procedure, and the adjustment of a noble gas mass spectrometer. A resolving power of about 550 at the 5% level of the peak height was attained for the complete separation of 3He ions from those of HD and H3. The reproducibility of the helium isotope ratio was about 1%, examined by repeated measurements of an air standard. The accuracy of the ratio was checked by comparing observed data with reports in the literature. The results show that it is possible to apply the present system to geohydrology

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    Trace amounts of Pt- and Ru-doped Ni/Mg(Al)O catalysts were prepared by a citrate method and tested in the oxidative reforming of C3H8 under daily start-up and shut-down (DSS) operation. The activity and the sustainability of the catalysts were compared with those of the Pt- and Ru-doped Ni/Mg(Al)O catalysts derived from hydrotalcite (HT) precursor. The DSS operation of C3H8 reforming was carried Out with O-2 gas or O-2/H2O mixed gas between 200 degrees C and 600 degrees C or 700 degrees C under air purging conditions. The catalysts underwent steaming treatment with H-2/H2O mixed gas at 900 degrees C for 10 h. This allowed us to test the effect of Ni sintering on the catalyst deactivation. Coking was significantly suppressed on both HT- and citrate-derived Ni catalysts. Although both preparations produced highly dispersed Ni particles on the catalysts, the HT-derived catalysts exhibited more finely dispersed Ni particles, resulting in higher activity values than those of the citrate-derived catalysts, The regenerative activity due to redispersion of sintered Ni particles was enhanced over the HT-derived catalysts compared with the activity over citrate-derived catalysts. Although a clear redispersion of Ni particles was not observed in the oxidative reforming, i.e., in the absence of steam, the size decrease in Ni particles was more significant over the HT-derived catalysts than over the citrate-derived catalysts. The Mg(Al)O periclase structure derived from Mg-Al HT likely plays an important role in the regenerative activity of Pt- and Ru-Ni/Mg(Al)O catalysts. Pt-doping was more effective than Ru for the catalyst sustainability in the oxidative reforming of C3H8

    Optimization of Ladle Tilting Speed for Preventing Temperature Drops in the Die Casting Process

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    In die casting, molten metal poured into a shot sleeve is pressed into a mold by a plunger at high speed. The temperature of the metal drops significantly while it is being poured from the ladle to the shot sleeve, resulting in casting defects such as misrun flow lines. Although it is important to control the temperature at all stages of the process, a method for minimizing temperature loss has not yet been clarified to date. In this study, the cause of the temperature drop in the shot sleeve was clarified, and a method of optimizing the ladle tilting speed was proposed to prevent temperature drop. First, experiments were conducted to measure the decrease in metal temperature in the sleeve during pouring. These experiments revealed that the metal cools significantly from the moment it touches the shot sleeve. Therefore, the time from the first contact between the shot sleeve and the metal to the start of pouring was set as the objective function. A genetic algorithm was then used to derive the optimal ladle tilting speed pattern to suppress the temperature drop. This analysis confirmed that the metal was poured without flowing out or running ahead and that the immediate liquid level vibration after pouring was suppressed, thus ensuring stable pouring

    Synthesis of lamellar mesostructured calcium phosphates using n-alkylamines as structure-directing agents in alcohol/water mixed solvent systems

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    Lamellar mesostructured calcium phosphates constructed by ionic bonds were prepared by using n-alkylamines (n-C n H2n+1NH2, n = 8–18) at room temperature in the mixed solvent systems of aliphatic alcohol (C n H2n+1OH, n = 1–4) and water, and the synthetic conditions were investigated in detail. The mixed solvent systems suppressed the formation of crystalline calcium phosphates like brushite (CaHPO4·2H2O) and monetite (CaHPO4) at low temperatures, successfully affording pure lamellar mesostructured calcium phosphates. Other crystalline phases such as hydroxyapatite (Ca10(PO4)6(OH)2) were not formed under the conditions with the Ca/P molar ratios in the range of 0.7–1.0 in the starting mixtures. The Ca/P molar ratio of the lamellar mesostructured calcium phosphates was ca. 1.0, calculated by ICP and 31P MAS NMR data. Interestingly, the kind of alcohols strongly influenced the solubilities of calcium phosphate species and n-alkylamines, and then lamellar mesostructured phases were obtained with some morphological variation

    Investigation of bone invasion and underlying mechanisms of oral cancer using a cell line‑derived xenograft model

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    The cancer stroma regulates bone invasion in oral squamous cell carcinoma (OSCC). However, data on normal stroma are limited. In the present study, the effects of gingival and periodontal ligament tissue‑derived stromal cells (G‑SCs and P‑SCs, respectively) and human dermal fibroblasts (HDFs) on bone resorption and osteoclast activation were assessed using hematoxylin and eosin and tartrate‑resistant acid phosphatase staining in a cell line‑derived xenograft model. The results demonstrated that G‑SCs promoted bone invasion and osteoclast activation and inhibited osteoclast proliferation following crosstalk with the human OSCC HSC‑3 cell line, whereas P‑SCs inhibited bone resorption and promoted osteoclast proliferation in vitro but had a minimal effect on osteoclast activation both in vitro and in vivo following crosstalk with HSC‑3 cells. Furthermore, the effects of G‑SCs, P‑SCs and HDFs on protein expression levels of matrix metalloproteinase (MMP)‑9, membrane type 1 MMP (MT1‑MMP), Snail, parathyroid hormone‑related peptide (PTHrP) and receptor activator of NF‑ÎșB ligand (RANKL) in HSC‑3 cells in OSCC bone invasion regions were assessed using immunohistochemistry. The results demonstrated that G‑SCs had a more prominent effect on the expression of MMP‑9, MT1‑MMP, Snail, PTHrP, and RANKL, whereas P‑SCs only promoted RANKL and PTHrP expression and exerted a minimal effect on MMP‑9, MT1‑MMP and Snail expression. The potential genes underlying the differential effects of G‑SCs and P‑SCs on bone invasion in OSCC were evaluated using a microarray, which indicated that cyclin‑dependent kinase 1, insulin, aurora kinase A, cyclin B1 and DNA topoisomerase II alpha underlaid these differential effects. Therefore, these results demonstrated that G‑SCs promoted bone invasion in OSCC by activating osteoclasts on the bone surface, whereas P‑SCs exerted an inhibitory effect. These findings could indicate a potential regulatory mechanism for bone invasion in OSCC

    Fractional Reserve in Banking System

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    This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money not backed by any physical commodities) creation. According to a third point of view, which is expressed by conspiracy theory followers, a the fractional reserve system primary targets to control the money supply in favor of famous rich families, such as the Rothschild family. Although the fractional reserve system is criticized for many reasons, such as causing a moral hazard, cheating and being not transparent, it still functions successfully all over the world. At least the banking system still exists and seems to exist further. How crucial are the defi-ciencies in the fractional reserve system for which it is criticized? Can they be improved? Or maybe the fractional reserve system is not that up to date anymore and should be replaced by something totally different? To find answers to these questions, I studied history books, up-to-date materials and legisla-tion, especially acts published by the European Central Bank. In addition, I sent questionnaires to several banks in Finland and got examples from real bank practice, which in total helped me to form the final understanding of the role of the fractional reserve system in today’s economy

    Positron emission tomography assessments of phosphodiesterase 10A in patients with schizophrenia

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    [Background and hypothesis] Phosphodiesterase 10A (PDE10A) is a highly expressed enzyme in the basal ganglia, where cortical glutamatergic and midbrain dopaminergic inputs are integrated. Therapeutic PDE10A inhibition effects on schizophrenia have been reported previously, but the status of this molecule in the living patients with schizophrenia remains elusive. Therefore, this study aimed to investigate the central PDE10A status in patients with schizophrenia and examine its relationship with psychopathology, cognition, and corticostriatal glutamate levels. [Study design] This study included 27 patients with schizophrenia, with 5 antipsychotic-free cases, and 27 healthy controls. Positron emission tomography with [18F]MNI-659, a specific PDE10A radioligand, was employed to quantify PDE10A availability by measuring non-displaceable binding potential (BPND) of the ligand in the limbic, executive, and sensorimotor striatal functional subregions, and in the pallidum. BPND estimates were compared between patients and controls while controlling for age and gender. BPND correlations were examined with behavioral and clinical measures, along with regional glutamate levels quantified by the magnetic resonance spectroscopy. [Study results] Multivariate analysis of covariance demonstrated a significant main effect of diagnosis on BPND (p = .03). A posthoc test showed a trend-level higher sensorimotor striatal BPND in patients, although it did not survive multiple comparison corrections. BPND in controls in this subregion was significantly and negatively correlated with the Tower of London scores, a cognitive subtest. Striatal or dorsolateral prefrontal glutamate levels did not correlate significantly with BPND in either group. [Conclusions] The results suggest altered striatal PDE10A availability and associated local neural dysfunctions in patients with schizophrenia

    Flt1/VEGFR1 heterozygosity causes transient embryonic edema

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    Vascular endothelial growth factor-A is a major player in vascular development and a potent vascular permeability factor under physiological and pathological conditions by binding to a decoy receptor Flt1 and its primary receptor Flk1. In this study, we show that Flt1 heterozygous (Flt1+/−) mouse embryos grow up to adult without life-threatening abnormalities but exhibit a transient embryonic edema around the nuchal and back regions, which is reminiscent of increased nuchal translucency in human fetuses. Vascular permeability is enhanced and an intricate infolding of the plasma membrane and huge vesicle-like structures are seen in Flt1+/− capillary endothelial cells. Flk1 tyrosine phosphorylation is elevated in Flt1+/− embryos, but Flk1 heterozygosity does not suppress embryonic edema caused by Flt1 heterozygosity. When Flt1 mutants are crossed with Aspp1−/− mice which exhibit a transient embryonic edema with delayed formation and dysfunction of lymphatic vessels, only 5.7% of Flt1+/−; Aspp1−/− mice survive, compared to expected ratio (25%). Our results demonstrate that Flt1 heterozygosity causes a transient embryonic edema and can be a risk factor for embryonic lethality in combination with other mutations causing non-lethal vascular phenotype
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