Characteristics and tribological properties in water of Si-DLC coatings

Si-containing diamond-like carbon (Si-DLC) coatings with a Si content ranging between 0 (DLC) and 10 at.% were deposited by thermal electron excited plasma CVD method, and their characteristics and the tribological properties in water environment were investigated. The results showed that doped Si had little effect on the hardness and Young's modulus of the coatings. Increasing Si content reduced the friction and the wear of the mated ball, although the wear of the coatings increased. The wear of the counter ball occurred mainly in the early stage of rubbing. The Raman and XPS analysis revealed that the tribochemical reaction of Si-DLC coating occurred in water, and SiO_x(OH)_y gel was formed on the mated ball surface. It is considered that the tribochemical reaction is also responsible for the tribological properties of the Si-DLC coating and the counter ball, and the reaction may be accelerated by increasing the Si content. Failure-resistant capability is strongly governed by the characteristics of the coating, and can be improved by doping Si. There is an optimum Si content for increasing the failure-resistant capability and it was 6.6 at.% in this work.     

Measuring the effect of police surveillance on the prevention of traffic accidents

An approach for estimating the effect of preventive measures taken against traffic accidents is presented. A simple stochastic model as to the process of accident occurrence is provided and the relationship among vulnerable behavior, collisions, and police surveillance is formalized. Here vulnerable behavior is defined as the state prior to the collision in the process of accident occurrence, and police surveillance is selected as one of the preventive measures against the accident.

The procedures by which the model can be applied in practice are shown for the case of intersection accidents, and the effects of some intersection surveillance forms on accident prevention are calculated. The results suggest that police surveillance which affects vulnerable behavior reduces accidents and that each collision category differently has the most effective surveillance form.

It is concluded that vulnerable behavior, which increases the likelihood of accident occurrence, provides a more sensitive safety measure than accidents.     

Distinction of Leu and Ile Using a Ruthenium(II) complex by MALDI-LIFT-TOF/TOF-MS analysis

The novel N-terminal labeling method using a ruthenium(II) complex derivative characteristically indicated a(n) and d(n) (N-terminal) fragment ions in high sensitivity by MS/MS analysis (MALDI-LIFT or ESI-CID). Although these fragment ions depended on a fragmentation process by MS/MS analytical methods to some degree, each case indicated similar side-chain cleavage patterns. The labeling method allows accurate distinction of amino acid residues by MS/MS analysis even if the residues are structural isomers such as leucine and isoleucine. The method was applied to long-chain peptides and provided easy and rapid N-terminal sequencing.     

Quantitative detection system for maize sample containing combined-trait genetically modified maize

Various countries have established regulations that stipulate the labeling of agricultural commodities, feed, and food products that contain or are made from genetically modified (GM) material or that contain adventitious GM material in amounts that exceed certain threshold levels. While regulations in some countries refer to GM material on a weight per weight (w/w) percentage, the currently applied detection methods do not directly measure the w/w percentage of the GM material. Depending on the particular method and the sample matrix it is applied to, the conversion of analytical results to a w/w percentage is challenging or not possible. The first rapid PCR system for GM maize detection on a single kernel basis has been developed. The equipment for the grinding of individual kernels and a silica membrane-based 96-well DNA extraction kit were both significantly revised and optimized for this particular purpose, respectively. We developed a multiplex real-time PCR method for the rapid quantification of GM DNA sequences in the obtained DNA solutions. In addition, a multiplex qualitative PCR detection method allows for the simultaneous detection of different GM maize traits in each kernel and thereby for identification of individual kernels that contain a combination of two or more GM traits. Especially for grain samples that potentially contain combined-trait GM maize kernels, the proposed methods can deliver informative results in a rapid, precise, and reliable manner.     

Approaches for establishing predicted-no-effect concentrations for population-level ecological risk assessment in the context of chemical substances management

The establishment of rational frameworks for population-level ecological risk assessment (PLERA) in the context of chemical substances management is an important issue. We illustrate two feasible approaches for establishing predicted-no-effect concentrations (PNECs)for PLERA through a case study of 4-nonylphenol (4-NP) using life-cycle toxicity data for medaka (Oryzias latipes). We first quantified the potential impacts of 4-NP on medaka in terms of reduction of population growth rate (i). An age-classified population matrix model (daily time-step) was developed and used to combine life-cycle survivorship and fecundity data obtained from individual-level responses of medaka expDsed to 4-NP into population-level responses defined by the parameter lambda. Thereafter, from the resulting lambdas, two approaches for establishing population-level PNEC values were proposed and examined. We then derived the PNEC values for population-level impacts, based on (a) the threshold concentration, defined as the chemical concentration at which lambda = 1 as a value with a 95% confidence interval, and (b) the no-observed-effect concentration (NOEC) and the maximum-acceptable-toxic concentration (MATC). The results suggest that PNEC values of 4-NP ranging between 0.82 and 2.10 microg/L affect medaka population growth. Although these approaches have their limitations, current knowledge indicates that they are reasonable and practical for evaluating population-level impacts of chemicals, thereby serving as a case study for establishing PNEC values for PLERA in the context of chemical substances management and decision-making.     

Detection and identification of Wolbachia endosymbionts from laboratory stocks of stored-product insect pests and their parasitoids

Endosymbiotic bacteria belonging to the genus Wolbachia are maternally inherited and can cause various effects on the reproductive system of their invertebrate hosts. Owing to their critical effects on insect reproduction, Wolbachia are potential tools for future insect pest control strategies. Here, we explored Wolbachia infections among stock collections at the National Food Research Institute of Japan, where stored-product insect pests and their parasitoids are maintained. Diagnostic polymerase chain reactions (PCRs) and sequencing of a fragment of the Wolbachia surface protein (wsp) gene revealed that, among 59 strains (38 species) belonging to the Coleoptera, Psocoptera, Lepidoptera and Hymenoptera, 18 strains (13 species) were infected with Wolbachia. Among them, 14 strains of Wolbachia were identified based on wsp gene sequences. Database searches showed that at least 6 Wolbachia strains were shared by multiple host species. Co-infections with two distinct Wolbachia strains were found in the drugstore beetle Stegobium paniceum and Angoumois grain moth Sitotroga cerealella. Detection and characterization of Wolbachia strains from these pests and their parasitoids provide us with basic information for future pest control strategies using these endosymbiotic bacteria.     

Novel method for producing amorphous rice flours by milling without adding water

The present study investigated a novel milling method for producing amorphous rice starch without adding water. A new type of milling machine was developed (termed the shear and heat milling machine (SHMM)), which is capable of applying mechanical shear and heat during the milling process. The SHMM consisted of a pair of rice mortars attached to a servomotor and a ring heater. The heater was installed on the upper mortar; the temperature of the upper mortar was monitored and controlled by a thermal controller. Wide‐angle X‐ray diffraction (WAXD) analysis was used to determine the crystallinities of starch in rice flour samples produced using the SHMM at different milling temperatures. The WAXD data for milled rice flour that had been heated exhibited no diffraction peaks. This experimental result demonstrates that the developed SHMM produces amorphous rice starch easily by milling with heating without the addition of water. The milling conditions such as the shear and heat applied can be used to control the crystallinity of starch in rice.