Suppression of magnetic ordering in XXZ-type antiferromagnetic monolayer NiPS3

How a certain ground state of complex physical systems emerges, especially in two-dimensional materials, is a fundamental question in condensed-matter physics. A particularly interesting case is systems belonging to the class of XY Hamiltonian where the magnetic order parameter of conventional nature is unstable in two-dimensional materials leading to a Berezinskii-Kosterlitz-Thouless transition. Here, we report how the XXZ-type antiferromagnetic order of a magnetic van der Waals material, NiPS3, behaves upon reducing the thickness and ultimately becomes unstable in the monolayer limit. Our experimental data are consistent with the findings based on renormalization group theory that at low temperatures a two-dimensional XXZ system behaves like a two-dimensional XY one, which cannot have a long-range order at finite temperatures. This work provides experimental examination of the XY magnetism in the atomically thin limit and opens new opportunities of exploiting these fundamental theorems of magnetism using magnetic van der Waals materials.Comment: 57 pages, 24 figures (including Supplementary Information

Growth of Carbon Nanotubes on Carbon Fiber by Thermal CVD Using Ni Nanoparticles as Catalysts

AbstractNickel nanoparticles and thin film on carbon fiber have been prepared through electroless deposition. Moreover, carbon nanotubes were grown on carbon fiber covered by nickel nanoparticles using thermal chemical vapor deposition. The effects of changes in the thickness of the nickel catalyst layer and the growth temperature of carbon nanotubes were studied systemically, and the results are discussed in the present work

Bioconversion of CO to formate by artificially designed carbon monoxide:formate oxidoreductase in hyperthermophilic archaea

Ferredoxin-dependent metabolic engineering of electron transfer circuits has been developed to enhance redox efficiency in the field of synthetic biology, e.g., for hydrogen production and for reduction of flavoproteins or NAD(P)+. Here, we present the bioconversion of carbon monoxide (CO) gas to formate via a synthetic CO:formate oxidoreductase (CFOR), designed as an enzyme complex for direct electron transfer between non-interacting CO dehydrogenase and formate dehydrogenase using an electron-transferring Fe-S fusion protein. The CFOR-introduced Thermococcus onnurineus mutant strains showed CO-dependent formate production in vivo and in vitro. The maximum formate production rate from purified CFOR complex and specific formate productivity from the bioreactor were 2.2????????0.2 ??mol/mg/min and 73.1????????29.0 mmol/g-cells/h, respectively. The CO-dependent CO2 reduction/formate production activity of synthetic CFOR was confirmed, indicating that direct electron transfer between two unrelated dehydrogenases was feasible via mediation of the FeS-FeS fusion protein

Migration, assignment, and scheduling of jobs in virtualized environment

Abstract Migration is an interesting issue for managing resource utilization and performance in clusters. Recent advances in server virtualization have made migration a practical method to achieve these goals. Especially, the live migration of virtualized servers made their pausing times negligible. However, migration of a virtual machine (VM) can slow down other collocated VMs in multiresource shared systems, where all the system resources are shared among collocated VMs. In parallel execution environment, such sudden slow-down phase of systems is called system noise; it may slow down overall systems while increasing the variability of system performance. When we consider the virtual machine assignment problem as resource allocation, those performance issues are hard to be properly treated. In this work, we address how to consider performance in assigning VMs. To achieve this goal, we model a migration process of a VM instance as a pair of jobs that run at the hosts of sender and receiver. We propose a method to analyze the migration time and the performance impact on multiresource shared systems for completing given VM assignment plan. This study may contribute to create more robust performance in virtualized environment

Transcription Factor Sp1 Is Involved in Expressional Regulation of Coxsackie and Adenovirus Receptor in Cancer Cells

Coxsackie and adenovirus receptor (CAR) was first known as a virus receptor. Recently, it is also known to have tumor suppressive activity such as inhibition of cell proliferation, migration, and invasion. It is important to understand how CAR expression can be regulated in cancers. Based on an existence of putative Sp1 binding site within CAR promoter, we investigated whether indeed Sp1 is involved in the regulation of CAR expression. We observed that deletion or mutation of Sp1 binding motif (−503/−498) prominently impaired the Sp1 binding affinity and activity of CAR promoter. Histone deacetylase inhibitor (TSA) treatment enhanced recruitment of Sp1 to the CAR promoter in ChIP assay. Meanwhile, Sp1 binding inhibitor suppressed the recruitment. Exogenous expression of wild-type Sp1 increased CAR expression in CAR-negative cells; meanwhile, dominant negative Sp1 decreased the CAR expression in CAR-positive cells. These results indicate that Sp1 is involved in regulation of CAR expression

The Korean Bird Information System (KBIS) through open and public participation

<p>Abstract</p> <p>Background</p> <p>The importance of biodiversity conservation has been increasing steadily due to its benefits to human beings. Recently, producing and managing biodiversity databases have become much easier because of the information technology (IT) advancement. This made the general public's participation in biodiversity conservation much more practical than ever. For example, an openfree web service can be devised for a wider spectrum of people to collaborate with each other for sharing biodiversity information. Bird migration is one such area of the collaboration. Korean migratory birds are usually traceable in the important routes of the East Asian-Australia Flyway (EAAF), and they play a key role as an environmental change indicator of the Earth. Therefore, the preservation of migratory birds requires an information system which involves a broader range of voluntary and interactive knowledge network to process bird information production, circulation, and dissemination.</p> <p>Results</p> <p>The Korean Bird Information System (KBIS) aims to construct a cooperative partnership domestically and internationally through the acquisition, management, and sharing of Korean bird information involving both expert and non-expert groups. KBIS has six goals: data standard, system linkage, data diversity, utilization, bird knowledge network, and statistics. The key features of KBIS are to provide a simple search, gallery (photographs), and community to lead the participation of numerous non-experts, especially amateur bird watchers. The function of real-time observation data submission through the internet has been accomplished. It also provides bird banding database, statistics, and taxon network for experts. Especially, the statistics part provides the user with easy understanding of ecological trends of species based on the time and region.</p> <p>Conclusion</p> <p>KBIS is a tool for the conservation and management of bird diversity and ecosystem that encourages users to participate by providing the openfree data access and real-time data input web-interface. It will enhance bird knowledge networking activities locally, nationally, and internationally. In addition, it provides opportunities to enhance the public awareness for the preservation of bird diversity and species information in relevant localities through the database construction and networking activities. It can be found at <url>http://korbird.naris.go.kr</url>.</p

Titanium dioxide induces apoptotic cell death through reactive oxygen species-mediated Fas upregulation and Bax activation

Background: Titanium dioxide (TiO2) has been widely used in many areas, including biomedicine, cosmetics, and environmental engineering. Recently, it has become evident that some TiO2 particles have a considerable cytotoxic effect in normal human cells. However, the molecular basis for the cytotoxicity of TiO2 has yet to be defined.Methods and results: In this study, we demonstrated that combined treatment with TiO2 nanoparticles sized less than 100 nm and ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-dependent upregulation of Fas and conformational activation of Bax in normal human cells. Treatment with P25 TiO2 nanoparticles with a hydrodynamic size distribution centered around 70 nm (TiO2P25-70) together with ultraviolet A irradiation-induced caspase-dependent apoptotic cell death, accompanied by transcriptional upregulation of the death receptor, Fas, and conformational activation of Bax. In line with these results, knockdown of either Fas or Bax with specific siRNA significantly inhibited TiO2-induced apoptotic cell death. Moreover, inhibition of reactive oxygen species with an antioxidant, N-acetyl-L-cysteine, clearly suppressed upregulation of Fas, conformational activation of Bax, and subsequent apoptotic cell death in response to combination treatment using TiO2P25-70 and ultraviolet A irradiation.Conclusion: These results indicate that sub-100 nm sized TiO2 treatment under ultraviolet A irradiation induces apoptotic cell death through reactive oxygen species-mediated upregulation of the death receptor, Fas, and activation of the preapoptotic protein, Bax. Elucidating the molecular mechanisms by which nanosized particles induce activation of cell death signaling pathways would be critical for the development of prevention strategies to minimize the cytotoxicity of nanomaterials.This work was supported by the Korea Ministry of Environment and The Eco-Technopia 21 Project (091-091-081)

Estimation of Electromagnetic Field Penetration into Concrete Buildings Using a Theoretical Approach Considering External Environmental Factors

In this paper, we propose a theoretical approach to estimate the power level of electromagnetic waves radiated into a structure by a specific external source. The target structure is a multistory building on a university campus that is used primarily for academic purposes and is much larger than the target wavelength. To verify the accuracy and efficiency of the proposed theoretical approach, measurements were carried out and a commercially available simulation tool, Wireless Insite, was adopted. We then analyzed the influence of an area of vegetation as an external environmental factor that could affect the radiated electromagnetic waves because of its location in front of the target structure. For this, a precise simulation environment was designed to derive the quantitative values of the electromagnetic attenuation caused by the external environmental factor. Furthermore, those values were applied to the theoretical approach. The results of the theoretical approach accounting for the external environmental factor were similar to those of the actual measured results. The results were also similar to those of the simulation tool, Wireless Insite, but the theoretical approach provided more efficient analysis results in terms of time consumption and computer resources

The Volume of Subscapularis Muscle Remains Unaffected by Supraspinatus Tendon Tears: Three-dimensionally Reconstructed Magnetic Resonance Imaging Analysis

Background This study aimed to compare the subscapularis muscle volume between the intact groups (group I) and supraspinatus tendon tear groups (group T) based on the sex and three different age groups. Methods Subjects with a group I and subjects with group T without any other lesions were retrospectively evaluated from among patients who received a magnetic resonance imaging (MRI) scan between January 2011 and December 2013. The MRI scans were studied by a consultant radiologist. The subscapularis muscle volume was compared according to the age and sex; the age groups were categorized as patients in their 40s, 50s, and 60s. The volume of subscapularis muscle was measured by three-dimensional reconstructed images acquired through the axial section of 1.5T MRI. Results No statistically significant differences were observed between subscapularis muscle volume of the group I and group T, except for male patients in their 50s (group I: 100,650 mm3 vs. group T: 106,488 mm3) and 60s (group I: 76,347 mm3 vs. group T: 99,549 mm3) (p<0.05). Males had a larger mean volume of subscapularis muscle than females, and the subscapularis muscle volume decreased in a linear manner with increasing age. Conclusions Decrease in subscapularis muscle volume was observed with increasing age, and the impact of supraspinatus tear on subscapularis muscle volume is age and sex dependent