Collective Josephson vortex dynamics in a finite number of intrinsic Josephson junctions

We report the experimental confirmation of the collective transverse plasma modes excited by the Josephson vortex lattice in stacks of intrinsic Josephson junctions in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ single crystals. The excitation was confirmed by analyzing the temperature ($T$) and magnetic field ($H$) dependencies of the multiple sub-branches in the Josephson-vortex-flow region of the current-voltage characteristics of the system. In the near-static Josephson vortex state for a low tunneling bias current, pronounced magnetoresistance oscillations were observed, which represented a triangular-lattice vortex configuration along the c axis. In the dynamic vortex state in a sufficiently high magnetic field and for a high bias current, splitting of a single Josephson vortex-flow branch into multiple sub-branches was observed. Detailed examination of the sub-branches for varying $H$ field reveals that sub-branches represent the different modes of the Josephson-vortex lattice along the c axis, with varied configuration from a triangular to a rectangular lattices. These multiple sub-branches merge to a single curve at a characteristic temperature, above which no dynamical structural transitions of the Josephson vortex lattice is expected

Heating-compensated constant-temperature tunneling measurements on stacks of Bi2_2Sr2_2CaCu2_2O8+x_{8+x} intrinsic junctions

In highly anisotropic layered cuprates such as Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ tunneling measurements on a stack of intrinsic junctions in a high-bias range are often susceptible to self-heating. In this study we monitored the temperature variation of a stack ("sample stack") of intrinsic junctions by measuring the resistance change of a nearby stack ("thermometer stack") of intrinsic junctions, which was strongly thermal-coupled to the sample stack through a common Au electrode. We then adopted a proportional-integral-derivative scheme incorporated with a substrate-holder heater to compensate the temperature variation. This in-situ temperature monitoring and controlling technique allows one to get rid of spurious tunneling effects arising from the self-heating in a high bias range.Comment: 3 pages, 3 figure

Effect of laser-dimpled titanium surfaces on attachment of epithelial-like cells and fibroblasts.

PurposeThe objective of this study was to conduct an in vitro comparative evaluation of polished and laserdimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti.Materials and methodsForty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had 5-µm dimples at 10-µm intervals, and SM30 (n=16) had 5-µm dimples at 25-µm intervals in a 2 × 4 mm(2) area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences.ResultsThe adhesion strength of epithelial cells was higher on Ti surfaces with 5-µm laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins.ConclusionThese findings demonstrate that laser dimpling may contribute to improving the periimplant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment

Association of factor XIII Val34Leu polymorphism and coronary artery disease: A meta-analysis

Background: Factor XIII plays an important role in the stabilization of the linkage between fibrins and in the pathophysiology of coronary artery disease (CAD). The association between factor XIII Val34Leu polymorphism and CAD risk remains controversial. Methods: We conducted a meta-analysis of 36 studies involving 26,940 cases and 34,694 controls. Subgroup analyses were performed with division of data into disease (myocardial infarction [MI], CAD without MI), age, and sex. Results: Factor XIII Val34Leu polymorphism was significantly associated with ove all CAD risk (odds ratio [OR] = 1.09, 95% confidence interval [CI] = 1.03–1.06, p = 0.004) and MI risk (OR = 1.15, 95% CI 1.07–1.25, p = 0.0003), but not with CAD without MI risk (OR = 1.00, 95% CI 0.87–1.15, p = 0.96). In the subgroup analysis by age and sex, there was no association between Val34Leu polymorphism and CAD. Conclusions: This meta-analysis found that factor XIII Val34Leu polymorphism was associated with CAD risk, especially MI, but not with CAD without MI. In addition, age and sex did not affect the relationship between factor XIII Val34Leu polymorphism and CAD risk.

Josephson-vortex-flow terahertz emission in layered high-TcT_c superconducting single crystals

We report on the successful terahertz emission (0.6$\sim$1 THz) that is continuous and tunable in its frequency and power, by driving Josephson vortices in resonance with the collective standing Josephson plasma modes excited in stacked Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ intrinsic Josephson junctions. Shapiro-step detection was employed to confirm the terahertz-wave emission. Our results provide a strong feasibility of developing long-sought solid-state terahertz-wave emission devices

Development of a Multi-material Stereolithography System

Researchers continue to explore possibilities for expanding additive manufacturing (AM) technologies into direct product manufacturing. One limitation is in the materials available for use in AM that can meet the needs of end-use applications. Stereolithography (SL) is an AM technology well known for its precision and high quality surface finish capabilities. SL builds parts by selectively crosslinking or solidifying photo-curable liquid resins, and the resin industry has been continuously developing new resins with improved performance characteristics. This paper introduces a unique SL machine that can fabricate parts out of multiple SL materials. The technology is based on using multiple vats positioned on a rotating vat carousel that contain different photo-curable materials. To change the material during the process, the build platform is raised out of the current vat, a new vat with a different material is rotated under the platform, and the platform is submerged into the new vat so that the new material can be used. This paper introduces a new vat exchange mechanism, cleaning process, recoating process, resin leveling mechanism and process planning technologies for the implementation of multiple material SL. An overview of the system framework is provided and the system integration and control software is described. In addition, several multiple material test parts are designed, fabricated, and described

Air-coupled Ultrasonic Tomography for Internal Damage of Full-Scale Reinforced Concrete Moment Frame Components Subjected to Seismic Loadings

Full-scale reinforced concrete (RC) components are imaged using ultrasonic tomography before, during, and after simulated earthquake loads, up to a drift level of 1%, are applied. A total of five RC moment frame components, including three columns and two slab-beam-column sub-assemblages, are subjected to three different seismic loading protocols. Two advanced structural materials, ultra-high-performance fiber-reinforced concrete (UHP-FRC) and high-performance fiber-reinforced concrete (HPFRC) are used in one of the columns and one of the slab-beam- column sub-assemblages, respectively. The components contain embedded strain gauges that are used to establish accumulated damage at certain locations. Our hybrid air-coupled ultrasonic system is used to collect a large volume of through thickness ultrasonic data across the plastic hinge zone region of the components. The ultrasonic data sets are used to back-calculate wave velocity tomograms across the cross-section at the plastic hinge regions for each component. A comparison of ultrasonic and strain gauge data shows the great potential of using ultrasonic tomography to evaluate damage progression of RC structures both at global and local levels. The results also confirm that UHP-FRC and HPFRC behave differently from conventional reinforced concrete

Role of Casein Kinase 1 in the Glucose Sensor-Mediated Signaling Pathway in Yeast

BackgroundIn yeast, glucose-dependent degradation of the Mth1 protein, a corepressor of the glucose transporter gene (HXT) repressor Rgt1, is a crucial event enabling expression of several HXT. This event occurs through a signaling pathway that involves the Rgt2 and Snf3 glucose sensors and yeast casein kinase 1 and 2 (Yck1/2). In this study, we examined whether the glucose sensors directly couple with Yck1/2 to convert glucose binding into an intracellular signal that leads to the degradation of Mth1. ResultsHigh levels of glucose induce degradation of Mth1 through the Rgt2/Snf3 glucose signaling pathway. Fluorescence microscopy analysis indicates that, under glucose-limited conditions, GFP-Mth1 is localized in the nucleus and does not shuttle between the nucleus and cytoplasm. If glucose-induced degradation is prevented due to disruption of the Rgt2/Snf3 pathway, GFP-Mth1 accumulates in the nucleus. When engineered to be localized to the cytoplasm, GFP-Mth1 is degraded regardless of the presence of glucose or the glucose sensors. In addition, removal of Grr1 from the nucleus prevents degradation of GFP-Mth1. These results suggest that glucose-induced, glucose sensor-dependent Mth1 degradation occurs in the nucleus. We also show that, like Yck2, Yck1 is localized to the plasma membrane via C-terminal palmitoylation mediated by the palmitoyl transferase Akr1. However, glucose-dependent degradation of Mth1 is not impaired in the absence of Akr1, suggesting that a direct interaction between the glucose sensors and Yck1/2 is not required for Mth1 degradation. ConclusionGlucose-induced, glucose sensor-regulated degradation of Mth1 occurs in the nucleus and does not require direct interaction of the glucose sensors with Yck1/2