極限環境応用のための4H-SiC半導体上の低抵抗・高信頼Ni/Nbオーミック接触形成

内容の要約広島大学(Hiroshima University)博士(理学)Doctor of Sciencedoctora

Antibiotic combinations to tackle Gram-negative bacterial pathogens : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biochemistry at Massey University, Manawatu Campus, New Zealand

Antimicrobial resistance, especially in Gram-negative bacterial pathogens, is one of the most serious threats with which humans have been confronted. Coordinated efforts from industrial, academic and government sectors have been called and executed to introduce novel antibiotics into the market to meet clinical demand. Despite that, the rate of successful antibiotic development appears to be lagging behind the emergence of antibiotic resistant pathogens in the arms race between humans and super-bugs. In this dire context, alternative approaches are required to tackle Gram-negative bacterial infections. This thesis reports synergistic interaction between a secondary bile salt, sodium deoxycholate (DOC), and 5-nitrofuran pro-drugs, an old class of synthetic antibiotics, in inhibiting/killing Gram-negative enterobacteria, such as Escherichia coli, Salmonella enterica and Citrobacter gillenii. Using a genetic approach, the underlying mechanism of the synergy between the two drugs was found to involve 5-nitrofuran-mediated inhibition of TolC-associated efflux pumps that otherwise exclude DOC from bacterial cells. This synergistic combination provides a promising tool to combat infections caused by enterobacterial pathogens. The mechanism of action of individual drugs, DOC and 5-nitrofurans, was also investigated using whole-genome sequence analyses of selected resistant mutants, followed by genetic and biochemical studies. A novel nitrofuran-activating enzyme, AhpF, was identified in E. coli that reduces 5-nitrofuran prodrugs in a manner different from that of an established 5-nitrofuran activation enzyme NfsB. This discovery opens new avenues to counteract nitrofuran-resistant clinical isolates by screening for molecules that upregulate AhpF expression or catalytic activity, or designing nitrofuran analogues activated at high efficiency by the AhpF enzyme. Also, this thesis identified mutations that cause a low-level resistance to DOC in efflux-pump-deficient genetic background. These all resulted in growth-slowing phenotype, the majority of which were involved in cAMP signaling. Singe mutations conferring high-level DOC-resistance were not identified in the mutant screen, supporting the use of DOC/nitrofuran combinations

Two-colour Three-pulse Spectrally Resolved Nonlinear Spectroscopy for Studies of Dynamics in Semiconductor Si Quantum Dots

We demonstrate that a two-colour three-pulsenonlinear spectroscopy can be used to study the dynamics of excited carriers inSi quantum dot structures embedded in SiN. Decays of the transverse optical phonon population and the transverse acoustic phonon population are measured and discussed. A simple theoretical modelis also used to support interpretation of our experimental observations

Dynamic R&D choice and the impact of the firms financial strength

This article investigates how a firm's financial strength affects its dynamic decision to invest in R&D. We estimate a dynamic model of R&D choice using data for German firms in high-tech manufacturing industries. The model incorporates a measure of the firm's financial strength, derived from its credit rating, which is shown to lead to substantial di¤erences in estimates of the costs and expected long-run benefits from R&D investment. Financially strong firms have a higher probability of generating innovations from their R&D investment, and the innovations have a larger impact on productivity and profits. Averaging across all firms, the long run benefit of investing in R&D equals 6.6 percent of firm value. It ranges from 11.6 percent for firms in a strong financial position to 2.3 percent for firms in a weaker financial position

Policy Response, Social Media and Science Journalism for the Sustainability of the Public Health System Amid the COVID-19 Outbreak: The Vietnam Lessons

Vietnam, with a geographical proximity and a high volume of trade with China, was the first country to record an outbreak of the new Coronavirus disease (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus 2 or SARS-CoV-2. While the country was expected to have a high risk of transmission, as of April 4, 2020—in comparison to attempts to contain the disease around the world—responses from Vietnam are being seen as prompt and effective in protecting the interests of its citizens, with 239 confirmed cases and no fatalities. This study analyzes the situation in terms of Vietnam’s policy response, social media and science journalism. A self-made web crawl engine was used to scan and collect official media news related to COVID-19 between the beginning of January and April 4, yielding a comprehensive dataset of 14,952 news items. The findings shed light on how Vietnam—despite being under-resourced—has demonstrated political readiness to combat the emerging pandemic since the earliest days. Timely communication on any developments of the outbreak from the government and the media, combined with up-to-date research on the new virus by the Vietnamese science community, have altogether provided reliable sources of information. By emphasizing the need for immediate and genuine cooperation between government, civil society and private individuals, the case study offers valuable lessons for other nations concerning not only the concurrent fight against the COVID-19 pandemic but also the overall responses to a public health crisis

"Cultural additivity" and how the values and norms of Confucianism, Buddhism, and Taoism co-exist, interact, and influence Vietnamese society: A Bayesian analysis of long-standing folktales, using R and Stan

Every year, the Vietnamese people reportedly burned about 50,000 tons of joss papers, which took the form of not only bank notes, but iPhones, cars, clothes, even housekeepers, in hope of pleasing the dead. The practice was mistakenly attributed to traditional Buddhist teachings but originated in fact from China, which most Vietnamese were not aware of. In other aspects of life, there were many similar examples of Vietnamese so ready and comfortable with adding new norms, values, and beliefs, even contradictory ones, to their culture. This phenomenon, dubbed "cultural additivity", prompted us to study the co-existence, interaction, and influences among core values and norms of the Three Teachings--Confucianism, Buddhism, and Taoism--as shown through Vietnamese folktales. By applying Bayesian logistic regression, we evaluated the possibility of whether the key message of a story was dominated by a religion (dependent variables), as affected by the appearance of values and anti-values pertaining to the Three Teachings in the story (independent variables).Comment: 8 figures, 35 page

Evaluation of graphical representations for the visualization of semantic data in a web interface

Das Wissen nutzbar zu machen steht an zentraler Stelle. Heute wird der Mensch mit Informationsmengen konfrontiert und steht dadurch vor dem Problem einer enormen Informationsflut. In der schnelllebigen Zeit der IT-Technik (Information und Telekommunikation) soll eine innovative Methode die Informationsrecherche zeitlich verkürzen und eine individuell optimale Lösung für den Benutzer gefunden werden. Die gebrauchstaugliche Unterstützung heißt: Eine semantisch-webbasierte Visualisierung zur Unterstützung des Findens innerhalb des Semantic Web. Der Ansatz der Visualisierung liegt darin begründet, dass Menschen hauptsächlich über die Augen wahrnehmen und schnell Zusammenhänge erkennen können. Sogar blinde Menschen nutzen dazu ein mentales System, das visuell räumliches Skizzenblatt (scratch-pad), um Bilder bzw. die Umwelt zu verarbeiten. Der Vorteil liegt darin begründet, dass es einen schnellen direkten Zugriff auf das Arbeitsgedächtnis ermöglicht. Ein Anwendungsszenario im Bereich des Mobilfunks soll als Praxisbeispiel dienen. Bei der Vielzahl der angebotenen Handys mit den homogenen Leistungen findet kaum ein Kunde die Unterscheidungen und es gibt zurzeit keine Möglichkeit unter den Handys benutzungsfreundlich zu differenzieren noch ein optimales Handy zu finden. Am Beispiel von selbst dargestellten Szenarien und einer Evaluation wird erörtert, wie anhand von angenommenen Stakeholder, ein Zusammenspiel der Semantic Web Technologien eine jeweilige Lösung von verfügbaren Informationen aufgefunden und bearbeitet werden kann. Ziel bei der Anwendung ist es, ein Prototypen zu realisieren, dass gebrauchstauglich bei der Visualisierung von großen Datenmassen, auf Grundlage einer Empfehlung von Mobilgeräten in einem Webinterface, unterstützt. Das bereits geschriebene Praxisprojekt-Referat in Form eines Konzepts mit dem Thema: „Graphische Visualisierung von semantischen Daten in einem Webinterface“ dient dabei als Grundlage für diese Bachelorarbeit (siehe Kap. 8.2). Grundlage, Innovationen und Beispiele aus der Praxis sind ausführlich dort beschrieben worden. Dabei wurden die neusten Technologien unter den Kriterien der Häufigkeit in der Praxis, Plattformunabhängigkeit und der Flexibilität betrachtet. Künstlerisch gestalterische Disziplinen, die Produkte graphisch zum Glänzen bringen möchten oder welche, die sich mit den grundlegenden Technologien für semantische Daten sich beschäftigen, bleiben bei dieser Arbeit unbehandelt. Es geht im Schwerpunkt um eine Beantwortung der folgenden Forschungsfrage: Inwieweit sind graphische Repräsentationen vorteilhafter, um Wissen zu vermitteln, in Verhältnis zu textuellen Repräsentationen

Estimating dynamic R&D demand : an analysis of costs and long-run benefits

Using firm-level data from the German manufacturing sector, we estimate a dynamic, structural model of the firm’s decision to invest in R&D and quantify the cost and longrun benefit of this investment. The model incorporates and quantifies linkages between the firm’s R&D investment, product and process innovations, and future productivity and profits. The dynamic model provides a natural measure of the long-run payoff to R&D as the difference in expected firm value generated by the R&D investment. For the median productivity firm, investment in R&D raises firm value by 3.0 percent in a group of hightech industries but only 0.2 percent in low-tech industries. Simulations of the model show that cost subsidies for R&D can significantly affect R&D investment rates and productivity changes in the high-tech industries

HIGHLY ANISOTROPIC MnBi MAGNETS

The rare-earth-free MnBi magnetic material is promising for high-temperature (150 200 oC) application of permanent magnets because of its large magnetocrystalline energy and especially the positive thermal coefficient of coercivity (dHc/dT 0). Because of the moderate value of the spontaneous magnetization Ms 74 emu/g, the anisotropy of MnBi bulk magnets should be investigated to enhance the remanence Mr. With large ratio Mr/Ms and appropriate microstructure, the squareness of MnBi magnets should have high value leading the remanent coercivity bHc close to the intrinsic coercivity iHc, thus enhancing the energy product (BH)max. The paper presents an approach to loading and compacting of MnBi powders in the 18 kOe magnetic field oriented perpendicular to the pressing direction where MnBi grains can be freely rotated and oriented parallel to the field direction. Based on the energy minimization of the assembly of magnetized grains, the compacting pressure was chosen to optimize two parameters, the mass density and the coercivity iHc of magnets. The prepared MnBi bulk magnet had 8.4 g/cm3, Mr/Ms 0.92, 0.89 and (BH)max reached 8.4 MGOe