Test-retest reliability of Purdue Pegboard performance in thermoneutral and cold ambient conditions

In the cold, Purdue Pegboard (PP) performance declines. The purpose of this study was to determine if this cold-induced impairment is consistent across days (i.e. test-retest reliability) in 5°C. In thermoneutral air (25°C), 14 men were familiarised to the dominant hand (PPa) and bimanual (PPb) PP tasks. They then experienced two 90-min cold exposures (Day 1, Day 2) while wearing ～1 clo. Bare hands were maintained throughout. Performance on both tasks showed high reliability from day to day (intraclass correlations >0.700) in both thermoneutral and cold conditions. However for both tasks, room temperature performance did not predict performance in the cold (intraclass correlations <0.450). When screening applicants for manual labour in the cold, one must consider that room temperature dexterity does not correlate with dexterity in the cold. It is recommended that a 60-min period of cold exposure be employed to assess manual dexterity in these workers. STATEMENT OF RELEVANCE: This study shows that PP performance in room temperature does not predict performance in the cold but performance in the cold is consistent from day to day. When screening applicants for manual labour in the cold, it is recommended that dexterity tests be conducted in the same ambient conditions.     

Pyroelectric properties and X-ray photoelectron spectroscopic study of R.F. magnetron-sputtering-derived PZT thin films deposited on various interlayers

PZT thin films and interlayers were fabricated by the radio frequency (r.f.) Magnetron-sputtering from the Pb_1.1Zr_0.53Ti_0.47O₃, PbO and TiO₂ target. As a result of the XPS depth profile analysis, we can confirm that the substrate temperature affects the oxidation condition of each element of interlayers and the PZT film. Compared to the PZT/Pt structure, the dielectric and pyroelectric properties of PZT thin films inserted by interlayers were measured to a relatively high value. In particular, the PZT/PbO structure had the highest pyroelectric properties (P = 189.4 μC/cm²K; F _D = 12.7×10⁻⁶ Pa^−1/2; F _V = 0.018 m²/C).     

Expression and Characterization of Monomeric Recombinant Isocitrate Dehydrogenases from Corynebacterium glutamicum and Azotobacter vinelandii for NADPH Regeneration

The enzymatic transformation of various chemicals, especially using NADPH-dependent hydroxylase, into more soluble and/or high value-added products has steadily garnered increasing attention. However, the industrial application of these NADPH-dependent hydroxylases has been limited due to the high cost of the cofactor NADPH. As an alternative, enzymatic NADPH-regeneration systems have been developed and are frequently used in various fields. Here, we expressed and compared two recombinant isocitrate dehydrogenases (IDHs) from Corynebacterium glutamicum and Azotobacter vinelandii in Escherichia coli. Both enzymes were hyper-expressed in the soluble fraction of E. coli and were single-step purified to apparent homogeneity with yields of more than 850 mg/L. These enzymes also functioned well when paired with NADPH consumption systems. Specifically, NADPH was regenerated from NADP⁺ when an NADPH-consuming cytochrome P450 BM3 from Bacillus megaterium was incorporated. Therefore, both enzymes could be used as alternatives to the commonly used regeneration system for NADPH. These enzymes also have promising potential as genetic fusion partners with NADPH-dependent enzymes due to the monomeric nature of their quaternary structure, thereby resulting in self-sufficient biocatalysts via NADPH regeneration in a single polypeptide with NADPH-dependent activity.     

Transcriptional Profiling of Whisker Follicles and of the Striatum in Methamphetamine Self-Administered Rats

Methamphetamine (MA) use disorder is a chronic neuropsychiatric disease characterized by recurrent binge episodes, intervals of abstinence, and relapses to MA use. Therefore, identification of the key genes and pathways involved is important for improving the diagnosis and treatment of this disorder. In this study, high-throughput RNA sequencing was performed to find the key genes and examine the comparability of gene expression between whisker follicles and the striatum of rats following MA self-administration. A total of 253 and 87 differentially expressed genes (DEGs) were identified in whisker follicles and the striatum, respectively. Multivariate and network analyses were performed on these DEGs to find hub genes and key pathways within the constructed network. A total of 129 and 49 genes were finally selected from the DEG sets of whisker follicles and of the striatum. Statistically significant DEGs were found to belong to the classes of genes involved in nicotine addiction, cocaine addiction, and amphetamine addiction in the striatum as well as in Parkinson’s, Huntington’s, and Alzheimer’s diseases in whisker follicles. Of note, several genes and pathways including retrograde endocannabinoid signaling and the synaptic vesicle cycle pathway were common between the two tissues. Therefore, this study provides the first data on gene expression levels in whisker follicles and in the striatum in relation to MA reward and thereby may accelerate the research on the whisker follicle as an alternative source of biomarkers for the diagnosis of MA use disorder.     

Etching characteristics and modeling for oval-shaped contact

In this study, etching characteristics of oval-shaped contact were investigated. The oval-shaped contact showed different etching characteristics compared to the circular contact. The long axis cross-section of oval-shaped contact showed a more vertical profile and a less bowing compared to the short axis. To explain these phenomena, we simulated ion reflection from sloped oval-shaped hard-mask. From the simulation, we found that the ions reflected from hard-mask accumulated more toward short axis sidewall first. This ion accumulation and asymmetric charging explained the reason behind larger bowing and slopped profile phenomena of short axis.     

Scalable network electrical devices using ZnO nanowalls

We report the fabrication and electrical characteristics of scalable nanowall network devices and their gas sensor applications. For the network device fabrications, two-dimensional ZnO nanowall networks were grown on AlN/Si substrates with a patterned SiO(2) mask layer using selective-area metal-organic vapor-phase epitaxy. The ZnO nanowalls with c-axis orientation were heteroepitaxially grown on AlN/Si substrates, and were single-crystalline, as determined by x-ray diffraction and transmission electron microscopy. The electrical conductivity of the nanowall networks was measured as a function of nanowall dimensions. The conductance increased linearly with the channel width for widths larger than 1 μm, but saturated at 36 μS for widths below 1 μm. This conductance scaling behavior is explained by enhanced conduction through the regions near the edge of the patterned growth areas, where the density of the networks was higher. Gas sensor applications were investigated using the nanowall network devices, and highly sensitive gas detection was demonstrated.     

New Insight into Microstructure Engineering of Ni-Rich Layered Oxide Cathode for High Performance Lithium Ion Batteries

Ni-rich layered LiNi_xCo_yMn_1−x−yO₂ (LNCM) with Ni content over >90% is considered as a promising lithium ion battery (LIB) cathode, attributed by its low cost and high practical capacity. However, Ni-rich LNCM inevitably suffers rapid capacity fading at a high state of charge due to the mechanochemical breakdown; in particular, the microcrack formation has been regarded as one of the main culprits for Ni-rich layered cathode failure. To address these issues, Ni-rich layered cathodes with a textured microstructure are developed by phosphorous and boron doping. Attributed by the textured morphology, both phosphorous- and boron-doped cathodes suppress microcrack formation and show enhanced cycle stability compared to the undoped cathode. However, there exists a meaningful capacity retention difference between the doped cathodes. By adapting the various analysis techniques, it is shown that the boron-doped Ni-rich layered cathode displays better cycle stability not only by its ability to suppress microcracks during cycling but also by its primary particle morphology that is reluctant to oxygen evolution. The present work reveals that not only restraint of particle cracks but also suppression of oxygen release by developing the oxygen stable facets is important for further improvements in state-of-the-art Li ion battery Ni-rich layered cathode materials.     

Simultaneous hydrogenation and hydroacylation of vinyl groups in polybutadiene by use of a rhodium catalyst

Vinyl groups in phenyl-terminated polybutadiene (1a) containing 99% unsaturation (27% vinyl group, 73% internal olefin), and for which the average M_n is 3400, were simultaneously hydrogenated and hydroacylated with various aromatic or heteroaromatic primary alcohols in the presence of the catalytic system RhCl₃.H₂O, PPh₃ and 2-amino-4-picoline. Sterically less hindered alcohols, such as benzyl alcohol, showed greater reactivity than sterically more hindered alcohols, such as 2-naphthylmethanol and heteroaromatic primary alcohols. Vinyl groups in phenyl-terminated polybutadiene (1b) containing 99% unsaturation (45% vinyl group, 55% internal olefin) and for which the average M_n is 1300 also showed similar reactivity toward various primary alcohols under identical reaction conditions.     

Multi-agent based traffic simulation and integrated control of freeway corridors: Part 1 simulation and control model

Freeway corridors consist of urban freeways and parallel arterials for alternative use. Ramp metering in freeways and signal control in arterials are contemporary traffic control methods that have been developed and applied in order to improve the traffic conditions of freeway corridors. However, most existing studies have focused on either optimal ramp metering in freeways or progressive signal strategies between arterial intersections. For efficient control of freeway corridors, ramp metering and signal control must be considered simultaneously, as otherwise the control strategies for freeway operation may disturb arterial traffic. On the other hand, traffic congestion and arterial bottlenecks that arise with increasing traffic volume at peak hours and ineffective signal operation may cause problems with accessibility to freeway ramps and degrade the urban freeway’s ability to act as a through-traffic process. This research dynamically estimates the traffic stream between an urban freeway and its ramps according to changes in the freeway structure, traffic passing demand, and control methods due to restricted valid information. The results are then compared with those from other methods. Finally, the integrated control in the urban freeway traffic axis is optimized based on the expected traffic stream, by using design of experiment (DOE), neural network (NN), and a simulated annealing algorithm. This paper was recommended for publication in revised form by Associate Editor Kyongsu Yi Myung-Won Suh is a professor of Mechanical Engineering. During 1986–1988, he worked in Ford motor company as researcher. During 1989–1995, he worked in technical center of KIA motors. He took a BS Degree in Mechanical Engineering from Seoul National University and an MS Degree in Mechanical Engineering from KAIST, South Korea. He obtained his Doctorate at University of Michigan, USA, in 1989. His research areas include the structure and system optimization, advanced safety vehicle and reliability analysis & optimization. Chul-Ho Bae is a PhD candidate at Sungkyunkwan University in Suwon, South Korea. He accomplished fellowship work as researcher at Mississippi State University, USA, in 2003 and 2005. He worked in Institute of Advanced Machinery and Technology (IMAT) as a Research Assistant in 2004. He was a part time Lecturer in computer aided Mechanical Engineering of Ansan College of Technology, Suwon Science College, and Osan College during 2004–2005. He took a BS Degree in Mechanical Design and an MS Degree in Mechanical Engineering from the Sungkyunkwan University. His research interests include computer aided engineering, reliability engineering, and optimization.     

Cloning and Sequence Analysis of the estA gene encoding enzyme for producing (R)-β-acetylmercaptoisobutyric acid from Pseudomonas aeruginosa 1001

The estA gene encoding the enzyme that catalyzes the production of (R)-β-acetylmercaptoisobutyric acid from (R,S)-ester from Pseudomonas aeruginosa 1001, was cloned in Escherichia coli and its nucleotide sequence was determined, revealing the presumed open reading frame encoding a polypeptide of 316 amino acid residues (948 nucleotides). The overall A+T and C+G compositions were 32.59% and 67.41%, respectively. The amino acid sequence of the estA gene product showed a significant similarity with that of the triacylglycerol lipase from Psychrobacter immobilis (38% identity), triacylglycerol lipase from Moraxella sp. (36% identity), and two forms of carboxyl esterases from Acinetobacter calcoaceticus (17% and 17% identities). The deduced amino acid sequences have a pentapeptide consensus sequence, G-X-S-X-G, having an active serine residue, and another active site, dipeptides H-G, located at 70–100 amino acids upstream of the G-X-S-X-G consensus sequence.