Classification of Fresh and Frozen‐thawed Fish by Near‐infrared Spectroscopy

ABSTRACT: Frozen fish usually have a much lower market price than fresh fish; therefore, adulteration could occur. This article focuses on the use of near infrared (NIR) spectroscopy to detect whether fish has been frozen‐thawed because NIR spectroscopy has demonstrated the potential for addressing some authenticity issue in foods and is known to be a nondestructive rapid technique. Horse mackerel (n = 162) were evaluated as fresh and frozen‐thawed fish sample. Dry extract spectroscopy by infrared reflection (DESIR) of fresh and frozen‐thawed fish samples was performed on the meat juices then discriminated by principal component analysis (PCA) and multiple linear regressions (MLR). In DESIR spectra, the overall absorbance level was found to decrease in frozen‐thawed samples, indicating the different chemical composition of juice, amount of dry matter, particle size, and their scattering properties. The spectral changes that take place between fresh and frozen‐thawed samples are clearly seen in the 1920‐ to 2350‐nm region. The spectra are dominated by peaks attributed to proteins, in particular, peaks at 1510, 1700, 1738, 2056, 2176, 2298, and 2346 nm. It was found that fresh and frozen‐thawed fish could be separated 100% correctly by DESIR technique.     

Mass spectrometric determination of waxy corn (Maize) starch in glutinous (waxy) rice cake by use of 13C/12C ratio

Glutinous (waxy) rice cake is a popular New Year food in Japan. Economic incentives exist for rice cake producers to adulterate the products and mislabel them. Stable carbon isotope ratios (¹³C/¹²C) in rice cake products were determined by mass spectrometry to detect such adulteration. Since the ¹³C/¹²C ratios in rice (δ¹³C value of ca - 25 ppt, parts per thousand are different from those of corn (maize) starch (ca ?9 ppt), the presence of added waxy corn (maize) starch in rice cake could be detected.     

A three-axis vibration isolation system using modified zero-power controller with parallel mechanism technique

This paper proposes a module-type three-degree-of-freedom vibration isolation system using modified zero-power control. Three vibration isolation modules are connected together using parallel mechanism to control 3-DOF motions. Each module consists of a common base, an individual middle mass and a common isolation table. The base to the middle mass is suspended by positive springs generated by active and passive system, and the middle mass and the isolation table is connected by negative spring realized by active-type modified zero-power control. The developed system could realize zero-compliance to direct disturbances as well as good ground vibration isolation. Furthermore, the isolation table is supported by a weight support mechanism for supporting heavy payloads. In the previous research, a concentrated middle mass with redundant actuators, in the vertical and horizontal directions, were used. Therefore, a vibration isolation system is proposed in this work using modular concept to overcome those drawbacks. Each module is controlled separately by decentralized control technique, and three modules can be used for three-degree-of-freedom of motion control. Therefore, no redundancy of actuator is occurred. Moreover, an improved zero-power controller is presented that can adjust negative stiffness instead of conventional zero-power controller. The results obtained from analytical and experimental studies show that the modular technique is reliable and efficient approach to vibration control, and represents a suitable alternative to the conventional active vibration isolation systems.     

Another approach toward over 100,000-fold sensitivity increase in capillary electrophoresis: electrokinetic supercharging with optimized sample injection

Electrokinetic supercharging (EKS) is a powerful and practical method for multifold in-line concentration of various analytes prior to capillary electrophoresis (CE) analysis. However, a problem of insufficient sensitivity has always existed when trace analyte quantification by EKS-CE is a target, especially when coupled with conventional detectors. Normally this requires a greatly increased amount of analyte injected without separation degradation. In this contribution, we have shown that it is possible to substantially improve analyte loading and hence CE method detectability by modifying sample introduction configuration. The volume of sample vial was increased (from typical 500 μL to 17 mL), the common wire electrode was replaced by a ring electrode, and the sample solution was stirred. With these alterations, more analyte ions are accumulated within the effective electric field during electrokinetic injection and then maintained as focused zones due to transient isotachophoresis. The versatility of the customized EKS-CE approach for sample concentration was demonstrated for a mixture of seven rare-earth metal ions with an enrichment factor of 500?000 giving detection limits at or below 1 ng/L. These detection limits are over 100?000 times better than can be achieved by normal hydrodynamic injection, 1000 times better than the sensitivity thresholds of inductively coupled plasma atomic emission spectrometry (ICP-AES), and even close to those of inductively coupled plasma mass spectrometry (ICPMS).     

Microscale phosphoproteome analysis of 10,000 cells from human cancer cell lines

We developed a miniaturized LC-MS system with a high-recovery phosphopeptide enrichment protocol that allows phosphoproteome analysis of 10(4) cells. In the enrichment protocol, the key step is to add sodium deoxycholate and sodium lauroyl sarcosinate to the buffer solution for protein extraction and digestion and to omit any subsequent desalt/desurfactant step before phosphopeptide enrichment. The phosphopeptides enriched by hydroxy acid-modified metal oxide chromatography (HAMMOC) are directly injected onto a miniaturized LC column using a nitrogen-pressure-driven cell, instead of switching valve-type injectors. The miniaturized analytical column of 25 μm diameter provided a 3.6-fold improvement in sensitivity over the conventional 100 μm diameter column. Overall, our analytical system provided approximately 80-fold improvement on average in the LC-MS response, and we identified 1011 unique phosphorylated sites based on 995 unique phosphopeptides from a single analysis of 10(4) HeLa cells (approximately 1 μg of proteins). This is the most sensitive phosphoproteomics system that has so far been reported for proteome-wide analysis of in vivo phosphorylation in mammalian cells.     

Discussion on framework of radon management strategy in various environments

Activities on radon management strategy of international organisations (International Atomic Energy Agency, International Commission on Radiation Protection, etc.) should be carefully and continuously traced to discuss how to control radon in various environments, for example, dwellings, workplace, underground, caves, mines, hot springs, disposal facilities and so on. It is more reasonable in parallel to set radon reference level by effective dose criteria of Sv y(-1) as well as by radon concentration in air of Bq m(-3). How to investigate radon concentration in each environment, and how to make decisions on needed action for radiation protection from natural radon,--these should be discussed for each environmental situation on a case-by-case basis. International discussion as well as domestic discussion is continuously needed, not only among the radon specialists and regulators, but also including stakeholders who are the main users of regulation and guidance.     

Dose evaluation from multiple detector outputs using convex optimisation

A dose evaluation using multiple radiation detectors can be improved by the convex optimisation method. It enables flexible dose evaluation corresponding to the actual radiation energy spectrum. An application to the neutron ambient dose equivalent evaluation is investigated using a mixed-gas proportional counter. The convex derives the certain neutron ambient dose with certain width corresponding to the true neutron energy spectrum. The range of the evaluated dose is comparable to the error of conventional neutron dose measurement equipments. An application to the neutron individual dose equivalent measurement is also investigated. Convexes of particular dosemeter combinations evaluate the individual dose equivalent better than the dose evaluation of a single dosemeter. The combinations of dosemeters with high orthogonality of their response characteristics tend to provide a good suitability for dose evaluation.