SUPERPLASTIC BEHAVIOUR OF LOW-ALLOY TOOL STEELS

From tensile and upsetting tests performed at various strain rates and temperatures we have established that the W9 tool steel, which is alloyed with a little Cr and W, shows superplastic behaviour at 710 cC, with a strain rate in the order of e = 10-4 s -1, and this state can be described by a sensitivity to strain rate exponent around m=O.5 (maximum m=0.52). The yield strength in this case is 60--100 MPa. On the basis of these data we can assume that the W9 steel is suitable for being processed by superplastic formation technology

Pathway optimization by re-design of untranslated regions for L-tyrosine production in Escherichia coli

None11Ysciescopu

Effects of the energy spread of secondary electrons in a dc-biased single-surface multipactor

The effects of the energy spread of secondary electrons are theoretically investigated for a dc-biased single-surface multipactor. In our previous publication [S. G. Jeon et al., Phys. Plasmas 16, 073101 (2009)], we obtained the conditions for the phase lock of an electron bunch, assuming zero velocity spread of the secondary electrons. In this work, we extended our previous theory to derive a quadratic map, by which the stability and bifurcation of the electron bunch can be systematically investigated. For the study of the energy spread of the secondary electrons, a randomized term was added to this map. The modified map then showed significant smearing-out of the bifurcated branches. The theoretical results were verified by particle-in-cell simulations, which showed good agreement in wide parameter ranges for both cases of monoenergetic and energy-spread secondary electrons.open4

Electron bunching from a dc-biased, single-surface multipactor with realistically broad energy spectrum and emission angle of secondary electrons

We studied the influences of wide energy spectrum and emission angle of secondary electrons on electron bunching from a dc-biased single surface multipactor. In our previous study of the same system, an ideally narrow energy spread of secondary electrons without emission angle was used in the analysis of the electron trajectory [M. S. Hur, J.-I. Kim, G.-J. Kim, and S.-G. Jeon, Phys. Plasmas 18, 033103 (2011) and S.-G. Jeon, J.-I. Kim, S.-T. Han, S.-S. Jung, and J. U. Kim, Phys. Plasmas 16, 073101 (2009)]. In this paper, we investigated the cases with realistic energy spectrum, which is featured by a wide energy spread and significant emission angle. To theoretically approach the matter of emission angle, we employed a concept of effective longitudinal velocity distribution. The theoretical results are verified by particle-in-cell (PIC) simulations. We also studied the electron bunching from a copper by PIC simulations, where we observed stable electron bunches with bunch width of approximately 80 mu m.open3

A paradox theory lens on proactivity, individual ambidexterity, and creativity:An empirical look

Paradox theory suggests that contradictory demands, like applying current work methods while exploring new ones, should be viewed as dualities with competing and complementary aspects. It advocates for employee ambidexterity, where employees must manage exploitation and exploration. We know little about how personal dispositions affect ambidexterity independently or when interacting with situational factors. Based on a time-lagged survey of 364 employee–supervisor pairs from 74 R&D teams, we found that proactive disposition was positively related to ambidexterity, enhancing creativity. Guided by trait activation theory, we found further that paradoxical supervision and job autonomy enhanced the relationship between proactive disposition and employee ambidexterity and the indirect effect of proactive disposition on creativity via ambidexterity. We discuss these findings' theoretical and practical implications, extending the literature on proactivity, ambidexterity, and paradox theory

Effect of amorphous Si quantum-dot size on 1.54 μm luminescence of Er

The role of the size of amorphous silicon quantum dots in the Er luminescence at 1.54 μm was investigated. As the dot size was increased, more Er ions were located near one dot due to its large surface area and more Er ions interacted with other ones. This Er-Er interaction caused a weak photoluminescence intensity, despite the increase in the effective excitation cross section. The critical dot size needed to take advantage of the positive effect on Er luminescence is considered to be about 2.0 nm, below which a small dot is very effective in the efficient luminescence of Er. © 2005 The Electrochemical Society. All rights reserved

Simultaneous Determination of Multiple microRNA Levels Utilizing Biotinylated Dideoxynucleotides and Mass Spectrometry

MicroRNAs (miRNAs) are important regulators of gene translation and have been suggested as potent biomarkers in various disease states. In this study, we established an efficient method for simultaneous determination of multiple miRNA levels, employing the previously developed SPC-SBE (solid phase capture-single base extension) approach and MALDI-TOF mass spectrometry (MS). In this approach, we first perform reverse transcription of miRNAs extracted using stem-loop primers. Then the cDNA is co-amplified with competitors, synthetic oligonucleotides whose sequences precisely match cDNA except for one base, and the amplicons serve as templates for a multiplexed SBE reaction. Extension products are isolated using SPC and quantitatively analyzed with MALDI-TOF MS to determine multiple miRNA levels. Here we demonstrated concurrent analysis of four miRNA levels utilizing the approach. Furthermore, we showed the presented method significantly facilitated MS analysis of peak area ratio owing to SPC. The SPC process allowed effective removal of irrelevant reaction components prior to MS and promoted MS sample purification. Data obtained in this study was verified with RT-qPCR and agreement was shown on one order of magnitude scale, suggesting the SPC-SBE and MS approach has strong potential as a viable tool for high throughput miRNA analysis.1110Ysciescopu

Bioluminescence-Activated Deep-Tissue Photodynamic Therapy of Cancer

Optical energy can trigger a variety of photochemical processes useful for therapies. Owing to the shallow penetration of light in tissues, however, the clinical applications of light-activated therapies have been limited. Bioluminescence resonant energy transfer (BRET) may provide a new way of inducing photochemical activation. Here, we show that efficient bioluminescence energy-induced photodynamic therapy (PDT) of macroscopic tumors and metastases in deep tissue. For monolayer cell culture in vitro incubated with Chlorin e6, BRET energy of about 1 nJ per cell generated as strong cytotoxicity as red laser light irradiation at 2.2 mW/cm(2) for 180 s. Regional delivery of bioluminescence agents via draining lymphatic vessels killed tumor cells spread to the sentinel and secondary lymph nodes, reduced distant metastases in the lung and improved animal survival. Our results show the promising potential of novel bioluminescence-activated PDT.111813Ysciescopu

One-flow Syntheses of Diverse Heterocyclic Furan Chemicals Directly from Fructose via Tandem Transformation Platform

The sustainable green chemistry associated with lignocellulosic biomass is of current interest for producing various chemical feedstocks via multi-step transformation processes. Here we introduce a chemical platform system for the multicomponent cascade transformation of natural lignocellulosic biomass resources. We demonstrate the concept by developing an integrated continuous two-step microfluidic system as a tandem transformation platform for direct conversion of fructose to diverse furan chemicals with excellent yields up to 99% via decarbonylation, etherification, oxidation and hydrogenolysis of a 5-hydroxymethylfurfural (HMF) intermediate. A sequential two-step process is utilized to complete the dehydration of fructose in the surface acid catalyst at 150 degrees C for 6 min, which is followed by the four types of HMF conversion in a binary or ternary phase to produce furfuryl alcohol (94% yield), 5-ethoxymethylfurfural (99%), 2,5-diformylfuran (82%) and 2,5-dimethylfuran (90%) with magnetic-based heterogeneous catalysts at 70-150 degrees C for 6-60 min. This innovative tandem microfluidic platform enables precise control of the reaction temperature and time for each individual biomass conversion step in a one-flow manner with no separation and purification steps for intermediates and catalysts.112016Ysciescopu

The first CCD photometric study of the open cluster NGC 2126

We present the first CCD photometric observations of the northern open cluster NGC 2126. Data were taken on eight nights in February and December 2002 with a total time span of ~57 hours. Almost 1000 individual V-band frames were examined to find short-period variable stars. We discovered six new variable stars, of which one is a promising candidate for an eclipsing binary with a pulsating component. Two stars were classified as delta Scuti stars and one as Algol-type eclipsing binary. Two stars are slow variables with ambiguous classification. From absolute VRI photometry we have estimated the main characteristics of the cluster: m-M=11.0+/-0.5, E(V-I)=0.4+/-0.1, E(V-R)=0.08+/-0.06 (E(B-V)=0.2+/-0.15) and d=1.3+/-0.6 kpc. Cluster membership is suggested for three variable stars from their positions on the colour-magnitude diagram.Comment: 7 pages, 10 figures, accepted for publication in A&