Schizophrenia is a debilitating psychiatric disorder, with a prevalence of approximately 1 % worldwide. The symptoms of schizophrenia include hallucinations and delusion (positive symptoms), apathy and withdrawal (negative symptoms), and cognitive impairments, which lead to disabilities in social and occupational functioning, and self-care. Although genetic elements have been extensively studied, the precise molecular mechanism of schizophrenia remains elusive. Recently, a role of reduced protein quality (protein aggregation) due to oxidative stress (carbonyl stress) and endoplasmic reticulum stress was proposed in the pathogenesis and pathology of schizophrenia. Here we explain the a current status of the research of schizophrenia while focusing on protein quality.
Metallomics is an omics study for the purpose of ubiquitously understanding the function and role of trace elements in biological activity. In this report, we introduce two topics of analytical techniques related to metallomics studies. ICP-MS have been widely used for the analysis of trace elements, but spectral interference problems sometimes prevent sensitive and accurate analysis. Although various methods had been invented to overcome the problems, the authors developed a simultaneous analytical method for the quantification of trace elements in blood by using sector-field ICP-MS which is more reliable in avoiding polyatomic interferences. We analyzed 25 elements in the human serum of patients with heart or kidney disease and healthy persons using the developed method, and examined the relationship between trace elements and those diseases by using multivariate data analysis. The results showed serum Se and Mn correlated strongly and those concentrations in heart disease patients were significantly lower than those in healthy persons. In particular, the selenium concentration showed a strong relationship with a cardiac function, such as a left ventricular ejection fraction. On the other hand, serum Cr, Ni, and Mo concentrations were significantly higher in dialysis patients. As described above, our study suggests that the kinetics of the trace elements may be causally related to disease conditions. Secondly, ICP-MS can obtain the positional distribution of trace elements in an analytical sample by combining with a laser ablation technique. Hence, we have also tried to develop a LA-ICP-MS imaging technique for biological samples. The trace-element distributions of a human hair strand and a mouse tissue section could be successfully obtained by one or two-dimensional LA-ICP-MS imaging. Furthermore, a multiplex bio-imaging was also obtained by staining with metal-tagged antibodies. Recent developments in ICP-MS and laser ablation techniques are also described along with the above two topics.
This paper describes a horizontal miniature developing chamber suitable for ultrathin layer chromatography (UTLC) and TLC-MS. The miniature developing chamber was designed by a CAD system and cut out from a PTFE block with a milling machine. The basic performance of the laboratory-made chambers was evaluated through TLC separations of lipids extracted from cyanobacteria on a commercially available silica gel 60-coated glass plate. The present miniature TLC chamber showed good performance comparable to a commercially available normal-size twin-trough vertical TLC chamber. In the present paper, ultra-thin layer plate was also prepared by decorating ZnO nanowires on a glass slide, and was applied to UTLC separation of synthetic pigments. The ZnO nanowire-array plate showed unique retention characteristics which allowed us to separate nile red and neutral red in the miniature TLC chamber.
XPS is capable of chemical-state analysis and is very useful for structural analysis. Since the information depth by XPS is as thin as about 10 nm, argon-ion sputtering should be used for the analysis of a deep region of samples. However, argon-ion sputtering may suffer damage such as a change in the chemical state depending on the type of sample. It was reported that zirconium oxide was not damaged by argon-ion sputtering, but there has been no report on a zirconium-based chemical conversion coatings. Therefore, in order to utilize XPS for microstructural analysis of zirconium-based chemical conversion coatings, which are widely used as corrosion-resistant coatings on paint bases, etc., possible damage of zirconium-based chemical conversion coatings by argon-ion sputtering was examined. As a result, it was confirmed that the zirconium-based chemical conversion coating was not damaged by argon-ion sputtering.
The stability of long-term storage was evaluated for 37 metal standard solutions and 12 non-metal ion standard solutions. A resin bottle or a glass bottle was used, depending on the kind of the standard solution. In addition, a case where the resin bottle was sealed in an aluminum-laminated plastic bag was also examined. The storage conditions were room-temperature storage and refrigerated storage. In the stability test, the solution mass in the bottle and the mass fraction of the target element or ions in the solution were monitored. Since the solution mass showed a decreasing tendency due to a evaporation of the solvent, the influence of the evaporation on the mass fraction of the target element or ions was evaluated based on the decrease rate of the solution mass. In addition, the stability of the target element or ions was evaluated by calculating the mass of the target element or ions in the standard solution as the product of the solution mass and the mass fraction of the target element or ions, and by estimating the dependence of the mass on the storage period. In consideration of these two evaluation results, the uncertainty of the long-term stability of the standard solution was evaluated.
In recent years, hydrogen has attracted remarkable attention as an energy vector which will help to reduce the emissions of CO2. According to the international standard (ISO 14687-2), the maximum concentration of sulfur in hydrogen used for fuel-cell vehicles should be lower than 0.004 ppm. In addition, the conventional method, such as gas chromatography, is unsuitable for determining the total sulfur content in hydrogen gas. In this study, a noble analytical instrument utilizing optical emission spectrometry was developed to determine the sulfur content in hydrogen gas. The instrument is composed of a pre-concentration device made of brass, a He-atmospheric pressure microhollow cathode discharge plasma as an excitation source, and a spectrometer. The instrument weights only ～2 kg, thus, it is portable. With the presented instrument, only 1.2 L of hydrogen gas is required to investigate whether 0.004 ppm of sulfur is contained or not.
A quantitative analysis of Ni(II) by anodic stripping voltammetry (ASV) was investigated using a three electrode system with a plastic formed carbon (PFC) electrode as a working electrode. When ASV was performed with 10 μmol L?1 Ni(II) aqueous solution containing 0.01 mol L?1 NaSCN and 0.1 mol L?1 KCl while rotating the PFC electrode at 2500 rpm, the positive peak current (Ip) was obtained at around –0.25 V due to the re-oxidation of Ni electrodeposited at the surface of PFC electrode. The Ip was proportional to the Ni(II) concentration in the range between 0.5 and 10 μmol L?1, and the limit of quantitation of Ni(II) was found to 1.7 μmol L?1. When 1 μmol L?1 Bi(III) was added to the 0.1 mol L?1 KCl aqueous solution instead of NaSCN and ASV was performed in the same manner, the Ip increased ca. 2-fold. The optimum condition for ASV of Ni(II) in 0.1 mol L?1 KCl aqueous solution containing 1 μmol L?1 Bi(III) was found to be the applied potential for the electrodeposition of Ni(II) of –1.6 V, the accumulation time of 900 s, the rotation rate of 2500 rpm, and the scan rate of 200 mV s?1, respectively. The Ip obtained by three repeated measurements under the optimum condition was proportional to the Ni(II) concentration in the range between 10 and 100 nmol L?1, and the correlation coefficient of the plot of Ip and Ni(II) concentration was R2 = 0.9922. The limit of quantitation of Ni(II) was found to 26 nmol L?1, which improved 65 time by adding Bi(III) compared with the addition of NaSCN. We have also clarified the conditions under which Ni(II) can be determined 10 times more sensitively than the water quality standard for drinking water.
In this work, we describe the absolute quantitative analysis of a chlorine dioxide (ClO2) based on a batch injection coulometry. The oxidation/reduction waves between ClO2 and the chlorate ion (ClO3?) in the cyclic voltammogram could be observed by using a carbon felt electrode in an acidic medium. The electrochemical performance for the electrode oxidation of ClO2 has successfully been applied to the batch injection coulometric determinations of ClO2 in water. The typical current response vs. time curve was measured by the repetitive determination of ClO2, and the measurement of ClO2 was fully completed in a short time (～20 s). The relative standard deviation (RSD) for fifteen successive measurements was found to be 2.98 %, indicating the good reproducibility of batch injection coulometric determinations. The oxidation current was actually increased as the sample solution volume increased. This fact indicates that the current response was generated by the electrode oxidation of ClO2. The electrical charge was proportional to the concentration range from 3 to 1000 ppm with a good linearity. The experimental value of the electrical charge for the electrode oxidation of ClO2 corresponding to the theoretical value of the electrical charge for the electrode oxidation of ClO2. Thus, the electrolysis efficiency for the ClO2 is expected to be nearly 100 % because extremely rapid determination is realized. Herein, our proposed batch injection coulometry is proven to be very promising for ClO2 measurements without calibration curves for sensor in practical applications.
Chemical and physical factors were measured in bottom sediments taken in coastal waters around Japan. They include concentration of 137Cs, stable elements, particle size distribution, organic carbon, nitrogen contents and density. Intercorrelations among the factors were calculated in order to study the relationship between the concentration of 137Cs and the physical and chemical factors of bottom sediments. Significant correlations (r > 0.8) existed between the 137Cs concentration and some factors such as total organic carbon, 75 μm passing rate and specific surface area in samples taken in areas without any impact of the Fukushima Dai-ichi Nuclear Power Station accident. However, the sediment samples taken in the waters off Miyagi, Fukushima and Ibaraki Prefectures, where accident-derived 137Cs was found, did not show any good relationships between 137Cs and any other factors, suggesting that newly added Fukushima-derived 137Cs, which was unevenly distributed in seawater, deposited onto the sediment irrespective of the pre-accident relationships among the chemical and physical factors.
Hydrostatic-pressure spectroscopy serves as a versatile analytical tool for elucidating a reaction or activation volume change (ΔV), enabling us not only to obtain deeper mechanistic insights into inherent basic science but also to apply to pressure-responsive chemosensor materials. Hydrostatic pressure is one of the most attractive external stimuli, and hence its effects on solutions have quite been investigated since the early 1960s. Recently, related studies attracted much attention as the fashionable mechanochromism and mechanobiology rose; solution-state effects upon hydrostatic pressurization are focused in this report, rather than solid-state chemistry under high pressure using a diamond anvil cell. In this review, we highlight our recent studies on hydrostatic-pressure spectroscopic chemistry.
We have developed a Sr adsorption fiber for the rapid analysis of 90Sr. The prepared Sr adsorption fiber has a Sr-extraction layer that densely retains a Sr-selective extractant, an 18-crown-6 ether derivative, on the fiber surface. Hydrophobic group-containing polymer chains embedded onto the surface of the fiber allow one to form a hydrophobic phase, incorporating Sr-selective extractants. This unique surface structure provides high adsorption capacity, leading to the rapid and highly efficient adsorption of Sr2+. The adsorption capacity of the Sr adsorption fiber was 3-times higher than commercially available 18-crown-6 ether derivative-impregnated resin (Sr Resin?). The equilibrium adsorption capacity of the Sr adsorption fiber was comparable to the Sr Resin?. The retained 90Sr was finally determined by a GM counter. The total analysis time, including the Sr adsorption and measurement, was about 1 hour.
A method for both the measurement of the source thickness and for evaluating its uncertainty of the U8 type cylindrical shaped radionuclide reference sources used for peak efficiency calibration of a gamma-ray spectrometer has been established. Essential information to measure the source thickness such as the height of the base level and a width of stopper for cover of the U8 container were clarified by measuring detailed dimensions of the 20 empty containers. The measurement of the source thickness and evaluating of its uncertainty were examined using dummy sources prepared with same materials as the reference sources. The examination clarified that: i) a vernier caliper is suitable for the thickness measurement due to its precision and utility; ii) the source thickness should be obtained by subtracting the mean height of the source measured at 4 places corresponding to the quartered bottom with the height of the base level for thickness measurement; iii) the standard uncertainty of the source thickness for 5 mm to 40 mm is found to be 0.4 mm; iv) the source thickness and its standard uncertainty of the reference source so called as “50 mm height”, which is unable to measure the thickness directly, are estimated to be 50. 7 mm and 0.7 mm, respectively. The peak efficiency of a gamma-ray spectrometer with a Ge detector was calibrated using the reference sources and was evaluated the uncertainty. The relative standard uncertainty of gamma-ray peak efficiencies for analyte nuclides such as 131I, 134Cs, 137Cs and 40K corresponding to source thickness were found to be 0.63 % to 1.0 %.
XPS (X-ray Photoelectron Spectroscopy) is a surface-sensitive analytical method that is performed in an ultra-high vacuum. Therefore, the samples should be carefully fixed with metal masks, plates, and screws, avoiding contamination. However, since powder samples cannot be fixed by these methods, they are while usually fixed with double-sided tape. The double-sided tape is convenient, but it has a weak point, that carbon from the tape is detected due to limited amounts of samples. Therefore, various fixing methods for powder samples have been examined, including JIS standard methods in this paper. It was found that the Al pan pressing method was the most stable and convenient fixing method for powder samples.
The sorption of inorganic mercury(II) was investigated using a solution containing organic compound. The presence of acetic acid and sodium acetate up to 0.2 mol L?1 as the total acetate concentration scarcely affected the sorption of mercury(II) by adding 100 mg of ground iron(II) sulfide to 100 mL of the solution, and then stirring the suspended solution. The effect of 50 v/v % of methanol, 30 v/v % of ethanol, acetonitrile, and N,N-dimethylformamide, or 1.0 v/v % of ethylenediamine was also not significant. Although the presence of acetone at 30 v/v % moderated the decrease in the mercury(II) concentration, the effect was not observed at 10 v/v %. The method for the sorption of mercury(II) with iron(II) sulfide, in which the operation is much simple, was applicable to the removal of mercury(II) in a real wastewater containing acetate.