In this study, investigation was performed on improving the X-band (9 GHz) electron spin resonance (ESR) imaging to detect and analyze melanin radicals contained in melanoma, a skin cancer. A new detector for non-invasive measurement was developed and a foothold was established for non-invasive measurement of melanin radicals inherent in skin diseases. As a result, it was found that pheomelanin (radical) is involved in malignant melanoma, and that the image intensity increases with the increasing stage of the melanoma. The pheomelanin radical was determined based on the hyperfine coupling constant. Furthermore, it was newly found that in other skin diseases in which melanin is involved, there is a good correlation between the degree of blackness of the skin disease and the ESR intensity, except for melanoma. In the case of melanoma, this correlation deviated from this correlation because eumelanin and pheomelanin radicals contributed to produce a stronger ESR signal. The main reason for this is thought to be that melanoma contains eumelanin and pheomelanin radicals. In this study, the sensitivity of the newly developed dielectric detector was significantly increased, and it was confirmed from the spectrum obtained by a single sweep that there was a pheomelanin radical in the melanoma sample.

Recognition compounds for ions can discriminate specific ions. Some of them conduct ion sensing accompanied by electrochemical or optical signals. Such recognition compounds are considered extremely attractive for use as ionophores or phosphors for ion sensors. Since the applied amounts of ion recognition compounds for ion sensors are extremely small, high performance is a requirement. In the molecular design of ion recognition compounds for ion sensors, therefore, it is important to design a suitable molecular structure for the capture of the target ion. In this paper, we introduced the molecular design of bis-type derivatives and C₃-bowl-type derivatives for ion recognition compounds, including examples with computational studies by conformational analysis of ab initio and semi-empirical methods. Bis-type derivatives enable the capture of the target ion with only one molecule, forming a 1 : 1 complex similar to a 2 : 1 complex. C₃-bowl-type derivatives can capture the target ion within its molecule by the coordinating substituents introduced in equilateral triangles. The ion selectivities of ion recognition compounds as ionophores were described to be influenced by both their topological and electrostatic properties, as shown by DFT calculations of saddle-shaped derivatives. Moreover, a summary is provided of some factors affecting the performance of ion-selective electrodes in the application of ion recognition compounds as ionophores. Also discussed in this paper are interesting physical properties such as the discotic-type liquid-crystalline compound and the thermoresponsive polymer that can be utilized for the change of ion sensing. It is also described that the proton spin-spin relaxation time T₂ measurement was effective for the evaluation of the ion-selective electrode membranes.

We have developed a new quantitative method for polysaccharide by sandwich enzyme-linked lectin assay (ELLA). In this high specificity method, polysaccharide is reacted with lectin immobilized in a 96-well microtiter plate, and then is sandwiched by enzyme-conjugated lectin, followed by color development by the enzyme activities. Guar gam was detected at a concentration from 0.1 μg mL⁻¹ to 3 μg mL⁻¹, and exopolysaccharide (EPS) from Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 (R-1) was detected at a concentration from 0.2 μg mL⁻¹ to 1 μg mL⁻¹ by this method. We quantified EPS in the culture fluid of R-1 strain after removing proteins by this method. The values obtained in spike and recovery test were from 97 % to 99 %. The precision of analysis was that repeatability was 6.2 % and intermediate precision was 6.8 %. These results showed this method had enough analytical ability. Furthermore, due to good operability, this method is expected to be applied to the quantification of various polysaccharides.

Concentrations of polycyclic aromatic hydrocarbons (PAHs) in sediments, anoxic muds and sandy muds, in the Yoro tidal flat (Ichihara City, Chiba Prefecture, Japan) were determined by gas chromatography-mass spectrometry (GC-MS). Anoxic muds were found to be widely distributed from the surface to the deeper layers (0 – 50 cm) of the sediment and the concentration of Total-PAHs in the muds fell in the range 201 – 358 μg kg-dry⁻¹, and was 4 to 7 times higher than that in the sandy mud. Analysis of stable isotope ratios of carbon (δ¹³C) showed the anoxic muds were derived from terrestrial plants such as fallen leaves; the upper reaches of the Yoro River may supply an abundance of fallen leaves, which pile up onto the tidal flat and decomposed reductively into organic muds. It was also found that the anoxic muds contain a large amount of perylene compared to the sandy mud; the perylene concentration, 51 – 80 μg kg-dry⁻¹, in the former was about 15 to 24 times higher than that in the latter. This finding suggested that decomposition of plant fragments leads to increasing the relative concentration of perylene.

This paper describes the development of a fast HPLC assay method of L-ascorbic acid employing HILIC mode and its application to the evaluation of photostability of unpacked pharmaceuticals and soft drinks containing L-ascorbic acid. Among four different types of HILIC columns, specifically amide type, diol type, pentahydroxy (5OH) type, and cyclodextrin type, of which most were core-shell type columns, a core-shell type 5OH column was selected after the optimization of the analytical conditions. With the mobile phase of 0.05 mol L⁻¹ ammonium formate and acetonitrile (25 : 75), three ascorbic acid analogues, isoascorbic acid (erythorbic acid), L-ascorbic acid and L-ascorbic acid 2-glucoside, were completely separated within 3 min in that order. The developed HILIC-HPLC L-ascorbic acid assay method using L-ascorbic acid 2-glucoside as an internal standard substance was applied to the photostability of pharmaceuticals once opened from the final packaging, such as a PTP sheet, and soft drinks with bottle caps removed. Photoirradiation was carried out in a light cabinet with a black light lamp with abundant wavelength of 365 nm. After 20 days irradiation, L-ascorbic acid content in the formulations was determined by the developed HPLC method and residual rates were compared with those not subjected to light irradiation (control samples). Among four dosage forms, namely tablets, granules, powders, and injections, some decrease was observed in the powders. For soft drinks, after removing the caps and irradiating with UV light for 2 days, the content of L-ascorbic acid decreased considerably and its rate correlated with the concentration of L-ascorbic acid. The lower concentration of L-ascorbic acid, the higher photodegradation of L-ascorbic acid. In soft drinks, even when stored in a refrigerator for a few days, the degradation of L-ascorbic acid was observed after opening.

Conductive carbon nanotube (CNT) fibers are attracting wide attention as an important material for realizing lightweight electric motors. Because conductivity depends on CNT length, it is important to understand CNT distribution. Traditional CNT length measurements obtained from SEM images are mainly performed manually, and this results in problems relating to time and repeatability. In this study, we address these problems by incorporating an image analysis program into the CNT length measurement process. We used an open-source image analysis program consisting of three processes (background, binarization, and skeletonization), and evaluated its applicability to CNT length measurement. The results show that the length measurement of a sample containing a large number of well-dispersed CNTs is comparable to that obtained from a manual measurement, and the program reduces working time and improves repeatability.