Mechanistic evidence for the remote π-aryl participation in acidcatalyzed ring opening of homobenzoquinone epoxides

The acid-induced reaction of bis(p-chlorophenyl)homobenzoquinone epoxide gave the dual ipso/ortho intramolecular SE2-Ar products associated with the π-aryl participated oxirane ring opening, whereas bis(p-tolyl)- and diphenyl-substituted homologues provided only the ortho products

Identification and Modulation of the Key Amino Acid Residue Responsible for the pH Sensitivity of Neoculin, a Taste-Modifying Protein

Neoculin occurring in the tropical fruit of Curculigo latifolia is currently the only protein that possesses both a sweet taste and a taste-modifying activity of converting sourness into sweetness. Structurally, this protein is a heterodimer consisting of a neoculin acidic subunit (NAS) and a neoculin basic subunit (NBS). Recently, we found that a neoculin variant in which all five histidine residues are replaced with alanine elicits intense sweetness at both neutral and acidic pH but has no taste-modifying activity. To identify the critical histidine residue(s) responsible for this activity, we produced a series of His-to-Ala neoculin variants and evaluated their sweetness levels using cell-based calcium imaging and a human sensory test. Our results suggest that NBS His11 functions as a primary pH sensor for neoculin to elicit taste modification. Neoculin variants with substitutions other than His-to-Ala were further analyzed to clarify the role of the NBS position 11 in the taste-modifying activity. We found that the aromatic character of the amino acid side chain is necessary to elicit the pH-dependent sweetness. Interestingly, since the His-to-Tyr variant is a novel taste-modifying protein with alternative pH sensitivity, the position 11 in NBS can be critical to modulate the pH-dependent activity of neoculin. These findings are important for understanding the pH-sensitive functional changes in proteinaceous ligands in general and the interaction of taste receptor–taste substance in particular

Evaluation of ITER TF Coil Joint Performance

To evaluate the ITER TF joint performance, the joint test sample, which consists of two short TF conductors and has full size joint, shall be tested using NIFS test facility under the condition of current of 68 kA and external field of 2 T. For high accuracy, the issue of voltage difference between cable and jacket had been anticipated in the evaluation of joint resistance. If a voltage difference exist between them, it is difficult to measure real joint resistance using voltage taps on the jacket. Therefore, the author first calculated the position where voltage of cable and jacket become equipotential and then decided the voltage tap position where the influence of voltage drop could be avoided. Thus, a high accuracy measurement of joint resistance could be achieved and the joint resistance was accurately evaluated as around 1 n Ω , which is well below the ITER requirement of 3 n Ω

Levels and Concentration Ratios of Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in Serum and Breast Milk in Japanese Mothers

Blood and/or breast milk have been used to assess human exposure to various environmental contaminants. Few studies have been available to compare the concentrations in one matrix with those in another. The goals of this study were to determine the current levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in Japanese women, with analysis of the effects of lifestyle and dietary habits on these levels, and to develop a quantitative structure–activity relationship (QSAR) with which to predict the ratio of serum concentration to breast milk concentration. We measured PBDEs and PCBs in 89 paired samples of serum and breast milk collected in four regions of Japan in 2005. The geometric means of the total concentrations of PBDE (13 congeners) in milk and serum were 1.56 and 2.89 ng/g lipid, respectively, whereas those of total PCBs (15 congeners) were 63.9 and 37.5 ng/g lipid, respectively. The major determinant of total PBDE concentration in serum and milk was the geographic area within Japan, whereas nursing duration was the major determinant of PCB concentration. BDE-209 was the most predominant PBDE congener in serum but not in milk. The excretion of BDE 209 in milk was lower than that of BDE 47 and BDE 153. QSAR analysis revealed that two parameters, calculated octanol/water partition and number of hydrogen-bond acceptors, were significant descriptors. During the first weeks of lactation, the predicted partitioning of PBDE and PCB congeners from serum to milk agreed with the observed values. However, the prediction became weaker after 10 weeks of nursing

Characterization of the Modes of Binding between Human Sweet Taste Receptor and Low-Molecular-Weight Sweet Compounds

One of the most distinctive features of human sweet taste perception is its broad tuning to chemically diverse compounds ranging from low-molecular-weight sweeteners to sweet-tasting proteins. Many reports suggest that the human sweet taste receptor (hT1R2–hT1R3), a heteromeric complex composed of T1R2 and T1R3 subunits belonging to the class C G protein–coupled receptor family, has multiple binding sites for these sweeteners. However, it remains unclear how the same receptor recognizes such diverse structures. Here we aim to characterize the modes of binding between hT1R2–hT1R3 and low-molecular-weight sweet compounds by functional analysis of a series of site-directed mutants and by molecular modeling–based docking simulation at the binding pocket formed on the large extracellular amino-terminal domain (ATD) of hT1R2. We successfully determined the amino acid residues responsible for binding to sweeteners in the cleft of hT1R2 ATD. Our results suggest that individual ligands have sets of specific residues for binding in correspondence with the chemical structures and other residues responsible for interacting with multiple ligands

Exploring the relationship between productive vocabulary knowledge and second language oral ability

The current study investigated the extent to which L2 learners’ productive vocabulary knowledge could predict multiple dimensions of spontaneous speech production. A total of 39 EFL participants with varying L2 proficiency levels first completed a productive vocabulary knowledge task (Lex30). Their spontaneous speech, elicited via a series of picture description task, was then assessed for comprehensibility (i.e., ease of understanding), accentedness (i.e., linguistic nativelikeness), and fluency (i.e., speech rate). The findings showed that the productive vocabulary scores significantly correlated with L2 fluency, but not with comprehensibility or accentedness. Such results might indicate that more proficient L2 learners, as indicated by their productive vocabulary scores, might be able to speak spontaneously without too many pauses and repetitions, and at a faster tempo. Finally, future research directions will be discussed with a focus on the relationships between vocabulary knowledge and speaking

Tactics to mitigate the negative impact of introducing advanced technology on employees: Evidence from large listed companies in Japan

This study examines how the introduction of advanced technology such as artificial intelligence adversely affects employees and the tactics to mitigate these negative effects. We surveyed 5438 employees working for large companies listed on the Tokyo Stock Exchange in nine industries in Japan. The questionnaire considered the five drivers of employee attitudes (skill acquisition, fair wages, work/life balance, relationship with supervisor, and diversity of human resources) as well as the introduction of advanced technology in workplaces. Using structural equation modeling, we revealed that the introduction of advanced technology increases turnover intention. While the effect is not observed for sales and marketing, it is evident among back-office and software development personnel. Further, this effect is more pronounced among younger workers and those who change jobs more frequently. Managers should consider not only the positive effect of cutting-edge technology, but also its adverse impact on employees

Microstructure and water distribution in catalysts for polymer electrolyte fuel cells, elucidated by contrast variation small-angle neutron scattering

By using small-angle neutron scattering (SANS) reinforced by scanning electron microscopy, the fine structure of catalysts for polymer electrolyte fuel cells has been investigated. The experimental data resulting from contrast variation with mixed light and heavy water (H2O/D2O) are well described by a core-shell model with fluctuations in concentration between water and Nafion. In particular, SANS obtained with the mixed water ratio 30/70, which corresponds to a matching point between mixed water and Nafion, shows a broad scattering maximum, which is attributed to a 5 nm-thick Nafion shell on the surface of the larger carbon particles. After swelling by water, the ionomer layer absorbs water at the 17 wt% level. By changing the H2O/D2O ratio, it was further confirmed that the catalyst with the ionomer exhibits water repellence, whereas the bare catalyst without the ionomer is wetted by water. Because it is very difficult to extract more information, for instance regarding the Pt-Nafion interactions, by means of small-angle scattering, reflectometry and grazing-incidence scattering experiments with neutrons should be attempted on a model catalyst prepared on a flat substrate

Effect of Advertising on Employee Turnover Intention:

Since internal marketing (IM) treats employees as customers, the focus has naturally been on internal measures. However, consumer-oriented advertising provides an opportunity for employees to recognize the social impact of their work and change their mindset. Such activities can be seen in business, but knowledge based on academic research is scarce. Therefore, this study examined the effects on job satisfaction and turnover intention by targeting ten factors, including advertising and nine factors covered in existing IM literature (capability acquisition, wages, work-life balance, relationship with superiors, diversity of human resources, office facilities, cafeteria, advanced technology, and purpose). An online survey of 5,000 full-time employees across ten industries (automotives, electronics, medical equipment, food, real estate, information technology, finance, retail, service, and government) was conducted in Japan. Advertisement had no effect on satisfaction, but had a significant positive effect on turnover intention. Furthermore, we found that the smaller the size of the company and the younger the employees, the more likely the employees are to change jobs. This result indicates the need to take care not to increase the desire to change jobs when promoting internal communication through advertisements