3,409 research outputs found
Li+ enhances GABAergic inputs to granule cells in the rat hippocampal dentate gyrus
No full textDefects in GABAergic interneurons are thought to be involved in the pathophysiology of bipolar disorder, and Li+ has been used as a primary therapeutic agent in the treatment. We used the patch clamp technique to investigate whether Li+ affects on spontaneous GABAergic synaptic inputs to granule cells (GCs) in hippocampal dentate gyrus. Extracellularly applied Li+ (25 mM) markedly increased the frequency and amplitude of spontaneous inhibitory postsynaptic currents (slPSCs), ail effect completely blocked by picrotoxin or bicuculline. Li+ increased slPSCs frequency in die presence of tetrodotoxin (TTX), but to a lesser extent than its absence. Li+ caused no change in the cumulative amplitude distribution of miniature IPSCs, indicating that a presynaptic mechanism is involved. When TTX was added in the presence of Li+, large-amplitude slPSCs (>30 pA) were abolished specifically with no effect on small-amplitude slPSCs (<20 pA). Intracellular Li+ (6 mM) applied via the patch pipette depolarized the resting membrane potential in fast-spiking interneurons, resulting in ail increase in spontaneous action potential (AP) firing. This change, however, was not observed in GCs. These results suggest that Li+-induced spontaneous AP firing in GABAergic interneurons contributes to the increase in GABAergic synaptic inputs to GCs. (C) 2004 Elsevier Ltd. All rights reserved
knockout mice prior to tumor development
No full textTo ascertain whether p53 deficiency in vivo leads to the deregulation of DNA methylation machinery prior to tumor development, we investigated the expression profile of DNA methyltransferases in the thymus and the liver of p53(+/+), p53(+/-), and p53(-/-) mice at 7 weeks of age before tumor development. The expression of DNA methyltransferases was examined in the thymus at 7 weeks of age, since the malignant T-cell lymphoma develops most frequently in p53(-/-) mice around 20 weeks of age. Both mRNA and protein levels of Dnmt1 and Dnmt3b were increased in the thymus and the liver of p53-deficient mice. The expression of Dnmt3a was also increased in the liver but not in the thymus of p53-deficient mice. Dnmt3L expression was reduced in the thymus of p53(+/-) and p53(-/-) mice. The total 5-methylcytosine (5-MeC) in the genomic DNA of p53(+/+), p53(+/-), and p53(-/-) mice was quantitated by dot-blot using antibody against 5-MeC. Global methylation was increased in the thymus and the liver of p53-deficient mice. To correlate the deregulated expression of DNA methyltransferases with the disturbance of the epigenetic integrity, we examined the DNA methylation of the imprinting control region (ICR) at the insulin-like growth factor II (Igf2/H19 loci in the thymus and the liver of p53(+/+), p53(+/-), and p53(-/-) mice. The region containing two CCCTC binding factor (CTCF) binding sites in the 5'-ICR tended to be hypomethylated in the thymus of p53(-/-) mice, but not in the liver. The expression profile of Igf2 and H 19 indicated that the thymus-specific changes of Igf2 and H 19 expression were coherent to the hypomethylation of the ICR in the thymus. Our results suggest that p53 is required for the maintenance of DNA methylation patterns in vivo. (C) 2004 Wiley-Liss, Inc.N
2020 Policy Consultation for the Kurdistan Regional Government I: Improving the Banking and Payment, Taxation System, Tourism Industry, and Industrial Investment
No full textThe “Policy Consultation for the Kurdistan Regional Government I” was carried out as the first round project under the agreement among the Kurdistan Regional Government (KRG), Korea National Oil Corporation and KDI School of Public Policy and Management. The four key consultation agendas were identified as top policy priorities by the KRG: (1) banking and payment, (2) taxation system, (3) tourism development, and (4) industrial investment. Our findings and recommendations for each policy area are summarized in this report.Preface
Executive Summary
Abbreviations
Chapter 1. Modernization of the Banking Services and Payment System
Highlights
1. Introduction
2. Current Situation and Challenges of the KRG
3. Banking and Payment System in South Korea
4. Experiences of Other Countries
5. Recommendations for Modernizing Banking and Payment System in KR
6. Conclusion and Future Consultation Areas
References
Appendix
Chapter 2. Establishment of a Comprehensive and Modern Tax Administration
Highlights
1. Introduction and Current Challenges of Tax Administration in KRG
2. Improving Tax Collection Methods
3. Building Database and Cashier Systems for Tax Offices
4. Connecting the Taxation Offices to the Relevant Government Offices through a Network
5. Organizing Year-end Accounting Budgets for Companies to Prevent Tax Evasion
6. Developing Data and Statistics for the Taxation Department
7. Developing a Government-Owned Point-of-Sales (POS) System
8. Developing Sophisticated Systems for Sales Taxation
9. Developing Sophisticated Systems for Corporate Taxation
10. Developing Sophisticated Systems for Income Taxation
11. Conclusion and Recommendations for Establishing a Comprehensive and Modern Tax Administration for KRG
References
Chapter 3. Lessons and Implications from Korean Experience for Promoting the Tourism Industry of the Kurdistan Region
Highlights
1. Introduction
2. Legal and Institutional Arrangement in Korea
3. Tourism Marketing in Korea
4. Tourism Human Resources Development in Korea
5. Infrastructure Development for Tourism in Korea
6. Conclusion and Future Consultation Areas
References
Appendix
Chapter 4. Promoting Industrial Investment through Smart Industrial Cluster and Institutional Reform Highlights
1. Introduction
2. Planning Guideline for Regional Industry (Cluster) Development in Kurdistan Region
3. Improving the Licensing Process for Industrial Projects
4. Improving the Quality Control and Examination System of Industrial Products
References
Appendi
Detection of fatigue crack on a rotating steel shaft using air-coupled nonlinear ultrasonic modulation
No full textRotating shafts in drop lifts of manufacturing facilities are susceptible to fatigue cracks as they are under repetitive heavy loading and high speed spins. However, it is challenging to use conventional contact transducers to monitor these shafts as they are continuously spinning with a high speed. In this study, a noncontact crack detection technique for a rotating shaft is proposed using air-coupled transducers (ACTs). (1) Low frequency (LF) and high frequency (HF) sinusoidal inputs are simultaneously applied to a shaft using two ACTs, respectively. A fatigue crack can provide a mechanism for nonlinear ultrasonic modulation and create spectral sidebands at the modulation frequencies, which are the sum and difference of the two input frequencies Then LF and HF inputs are independently applied to the shaft using each ACT. These three ultrasonic responses are measured using another ACT. (2) The damage index (DI) is defined as the energy of the first sideband components, which corresponding to the frequency sum and difference between HF and LF inputs. (3) Steps 1 and 2 are repeated with various combinations of HF and LF inputs. Crack existence is detected through an outlier analysis of the DIs. The effectiveness of the proposed technique is investigated using a steel shaft with a real fatigue crack
sj-docx-1-eso-10.1177_23969873221144814 – Supplemental material for Effects of prior antiplatelet use on futile reperfusion in patients with acute ischemic stroke receiving endovascular treatment
No full textSupplemental material, sj-docx-1-eso-10.1177_23969873221144814 for Effects of prior antiplatelet use on futile reperfusion in patients with acute ischemic stroke receiving endovascular treatment by Jong-Hee Sohn, Chulho Kim, Minwoo Lee, Yerim Kim, Hee Jung Mo, Kyung-Ho Yu and Sang-Hwa Lee in European Stroke Journal</p
Bayesian probabilistic damage detection of a reinforced-concrete bridge column
No full textA Bayesian probabilistic approach for damage detection has been proposed for the continuous monitoring of civil structures (Sohn H, Law KH. Bayesian probabilistic approach for structure damage detection. Earthquake Engineering and Structural Dynamics 1997; 26: 1259-1281). This paper describes the application of the Bayesian approach to predict the location of plastic hinge deformation using the experimental data obtained from the vibration tests of a reinforced-concrete bridge column. The column was statically pushed incrementally with lateral displacements until a plastic hinge is fully formed at the bottom portion of the column. Vibration tests were performed at different damage stages. The proposed damage detection method was able to locate the damaged region using a simplified analytical model and the modal parameters estimated from the vibration tests, although (1) only the first bending and first torsional modes were estimated from the experimental test data, (2) the locations where the accelerations were measured did not coincide with the degrees of freedom of the analytical model, and (3) there existed discrepancies between the undamaged test structure and the analytical model. The Bayesian framework was able to systematically update the damage probabilities when new test data became available. Better diagnosis was obtained by employing multiple data sets than just by using each test data set separately. Copyright (C) 2000 John Wiley & Sons, Ltd.The "rst author wishes to express his sincere thanks to Professor Gerard C. Pardoen and his students at the
University of California at Irvine for providing an opportunity to observe the bridge column test. Also, the
authors are indebted to Dr Charles R. Farrar and Dr Scott W. Doebling of the Los Alamos National
Laboratory for providing the vibration test data. This research was partially sponsored by the National
Science Foundation under Grant No. CMS-95261-2
and layer-by-layer grain size estimation in additively manufactured metal components using femtosecond laser ultrasonics
No full textDirected energy deposition (DED) is an additive manufacturing technique wherein a focused thermal energy source and a coaxial powder delivery system are combined for the fabrication of metallic parts. Although rapid progress has been made in DED, the amount of research performed for in situ quality monitoring during fabrication is limited. Grain size monitoring during DED is particularly important because the grain size is directly related to the mechanical strength and stiffness of the final products. In this study, a layer-by-layer grain size estimation technique using femtosecond laser ultrasonics is developed for in situ monitoring during DED. The proposed technique employs fully noncontact and nondestructive testing for grain size estimation and uses the relationship between the laser-induced ultrasonic waves and the grain size. In addition to the in situ operation of the technique, spatial resolution in the micrometer range was achieved. The developed technique was validated using Ti-6Al-4V specimens fabricated by DED. The results of the quantitative grain sizes measured by the developed method were consistent with those measured through independent metallography conducted after the completion of DED.
Effects of deformation-induced BCC martensitic transformation and twinning on impact toughness and dynamic tensile response in metastable VCrFeCoNi high-entropy alloy
No full textThe metastable high- and medium entropy alloys (HEAs or MEAs) have drawn many attentions regarding deformation mechanisms and mechanical properties. Most of their studies have conducted under quasi -static or uniaxial tensile/compressive loading conditions. For cryogenic applications, however, the fracture or impact toughness should be carefully evaluated because it is one of the most important indices for the low-temperature performance. In this study, quasi-static and dynamic tensile properties of a metastable VCrFeCoNi HEA were investigated at room and cryogenic temperatures, and they were systematically correlated with the Charpy impact toughness. Under the quasi-static tensile loading, the Twinning Induced Plasticity (TWIP) mechanism occurred at room temperature, while the Transformation Induced Plasticity (TRIP) from FCC to BCC phases via an intermediate HCP phase occurred at cryogenic temperature. Under the dynamic loading, more deformation twins were formed at room temperature, and the amount of martensite reduced at cryogenic temperature. These variations of twinning and martensitic transformation were elucidated by the raised flow stress and by the adiabatic heating effect, respectively. They were confirmed by combining with ab-initio calculations, leading to the strong dependency of the energetic stability of BCC and HCP phases relative to the FCC phase. As a result, a plenty of deformation twins under the dynamic loading resulted in the high impact toughness of 112.6 J at room temperature. The martensitic transformation and consequently refined network structure played key roles in sustaining the remarkable toughness and in preventing the DBT phenomenon as the test temperature decreased. (C) 2019 Elsevier B.V. All rights reserved.11Nsciescopu
Targeted deletion of Crif1 in mouse epidermis impairs skin homeostasis and hair morphogenesis
No full textAbstractThe epidermis, which consists mainly of keratinocytes, acts as a physical barrier to infections by regulating keratinocyte proliferation and differentiation. Hair follicles undergo continuous cycling to produce new one. Therefore, optimum supply of energy from the mitochondria is essential for maintaining skin homeostasis and hair growth. CRIF1 is a mitochondrial protein that regulates mitoribosome-mediated synthesis and insertion of mitochondrial oxidative phosphorylation polypeptides into the mitochondrial membrane in mammals. Recent studies reveal that conditional knockout (cKO) of Crif1 in specific tissues of mice induced mitochondrial dysfunction. To determine whether the mitochondrial function of keratinocytes affects skin homeostasis and hair morphogenesis, we generated epidermis-specific Crif1 cKO mice. Deletion of Crif1 in epidermis resulted in impaired mitochondrial function and Crif1 cKO mice died within a week. Keratinocyte proliferation and differentiation were markedly inhibited in Crif1 cKO mice. Furthermore, hair follicle morphogenesis of Crif1 cKO mice was disrupted by down-regulation of Wnt/β-catenin signaling. These results demonstrate that mitochondrial function in keratinocytes is essential for maintaining epidermal homeostasis and hair follicle morphogenesis.</jats:p
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