Ti-free optical waveguiding regions produced by LiNbO3 etching during the indiffusion of Ti

We report the observation, first to our knowledge, of optical waveguiding found beneath trenches etched in congruent lithium niobate using the recently reported etching during the indiffusion of Ti process. Observations of multi-mode and single-mode guiding at visible wavelengths and preliminary measurements of waveguide insertion losses are presented.     

Lower compactness estimates for scalar balance laws

In this paper, we study the compactness in L of the semigroup (St)_t≥0 of entropy weak solutions to strictly convex scalar conservation laws in one space dimension. The compactness of St for each t > 0 was established by P. D. Lax. Upper estimates for the Kolmogorov e‐entropy of the image of bounded sets in L¹ n L^∞ through S_t were given by C. De Lellis and F. Golse. Here we provide lower estimates on this e‐entropy of the same order as the one established by De Lellis and Golse, thus showing that such an e‐entropy is of size ≈ 1/ε. Moreover, we extend these estimates of compactness to the case of convex balance laws. © 2012 Wiley Periodicals, Inc.     

Multi-dimensional stability of planar Lax shocks in hyperbolic–elliptic coupled systems

We study nonlinear time-asymptotic stability of small-amplitude planar Lax shocks in a model consisting of a system of multi-dimensional conservation laws coupled with an elliptic system. Such a model can be found in context of dynamics of a gas in presence of radiation. Our main result asserts that the standard uniform Evans stability condition implies nonlinear stability. The main analysis is based on the earlier developments by Zumbrun for multi-dimensional viscous shock waves and by Lattanzio–Mascia–Nguyen–Plaza–Zumbrun for one-dimensional radiative shock profiles.     

The presence of high level soluble herpes virus entry mediator in sera of gastric cancer patients

The development of gastric cancer (GC) is closely related to chronic inflammation caused by Helicobacter pylori infection, and herpes virus entry mediator (HVEM) is a receptor expressed on the surface of leukocytes that mediates potent inflammatory responses in animal models. However, the role of HVEM in human GC has not been studied. Previously, we showed that the interaction of HVEM on human leukocytes with its ligand LIGHT induces intracellular calcium mobilization, which results in inflammatory responses including induction of proinflammatory cytokine production and anti-bacterial activities. In this study, we report that leukocytes from GC patients express lower levels of membrane HVEM (mHVEM) and have lower LIGHT-induced bactericidal activities than those from healthy controls (HC). In contrast, levels of soluble HVEM (sHVEM) in the sera of GC patients were significantly higher than in those of HC. We found that monocyte membrane-bound HVEM is released into the medium when cells are activated by proinflammatory cytokines such as TNF-α and IL-8, which are elevated in the sera of GC patients. mHVEM level dropped in parallel with the release of sHVEM, and release was completely blocked by the metalloprotease inhibitor, GM6001. We also found that the low level of mHVEM on GC patient leukocytes was correlated with low LIGHT-induced bactericidal activities against H. pylori and S. aureus and production of reactive oxygen species. Our results indicate that mHVEM on leukocytes and sHVEM in sera may contribute to the development and/or progression of GC.     

Symmetry preservation in a new noncentrosymmetric lattice comprised of acentric POM clusters residing in bowls of Cs(+)-based half SOD β-cage

In light of ever growing interests in noncentrosymmetric materials, a fascinating reticular chemistry is illustrated via the structure of a new family of solids where the acentric symmetry of the well-known [V(4+)(14)As(3+)(8)O(42)Cl](5-) POM cluster is manifested through the network construction of counter cations featuring slabs of Cs(+)-based half SOD β-cages.     

Synthesis and antibacterial activity of some heterocyclic chalcone analogues alone and in combination with antibiotics

A series of simple heterocyclic chalcone analogues have been synthesized by Claisen Schmidt condensation reactions between substituted benzaldehydes and heteroaryl methyl ketones and evaluated for their antibacterial activity. The structures of the synthesized chalcones were established by IR and 1H-NMR analysis. The biological data shows that compounds p?, f? and t? had strong activities against both susceptible and resistant Staphylococcus aureus strains, but not activity against a vancomycin and methicillin resistant Staphylococcus aureus isolated from a human sample. The structure and activity relationships confirmed that compounds f?, f? and t? are potential candidates for future drug discovery and development.     

Sample loading and retrieval by centrifugation in a closed-loop PCR microchip

We report on a novel concept of sample loading for microfluidic devices using a benchtop centrifuge and a magnetically actuated circular closed-loop PCR microchip as a model system. The PCR mixture and the ferrofluid were loaded into a specially designed microchip. The microchip was then placed in an off-the-shelf 50-mL tube and centrifuged. The strong centrifugal force drives the PCR mixture and the ferrofluid into the microchannels of the microchip, and simultaneously expels any trapped microbubbles. PCR was successfully carried out on single and parallel closed-loop PCR microchips. The addition of a few off-chip handling steps allows great simplification of the device design. This new loading concept may be useful for designing robust and low-cost lab-on-a-chip devices because benchtop centrifuges are quite common in most laboratories.

Synthesis of 2-(1-aminocyclopropyl)pyrrolidine-3,4-diol derivatives applying titanium-mediated reaction conditions

The titanium-mediated cyclopropanation reaction using Ti(OⁱPr)₃Me/EtMgBr/BF₃·OEt₂ has been applied to various 2-cyanopyrrolidines for the synthesis of functionalized 2-(1-aminocyclopropyl)pyrrolidine-3,4-diol derivatives (dideoxyiminoalditols). Under the same experimental conditions the trans-5-azidomethyl-2-cyanopyrrolidine derivative was not cyclopropanated but reduced into the corresponding 5-amino-2-cyano derivative. After polyol deprotection 2-(1-aminocyclopropyl)pyrrolidine-3,4-diols were obtained and their inhibitory activity towards 13 glycosidases has been evaluated. (2S,3S,4R,5S)-2-(1-Aminocyclopropyl)-5-methylpyrrolidine-3,4-diol (38), which has the same absolute configuration as l-fucose, is a moderate (IC₅₀=44 μM), but selective, inhibitor of α-l-fucosidase from human placenta.     

Geometric rigidity for analytic estimates of Müller–?verák

In the paper Müller–?verák (J Differ Geom 42(2):229–258, 1995) conformally immersed surfaces with finite total curvature were studied. In particular it was shown that surfaces with total curvature ${\int_{\Sigma} |A|^2 < 8 \pi}$ in dimension three were embedded and conformal to the plane with one end. Here, using techniques from Kuwert–Li (W ^2,2-conformal immersions of a closed Riemann surface into R ⁿ . arXiv:1007.3967v2 [math.DG], 2010), we will show that if the total curvature ${ \int_{\Sigma}|A|^2\leq8\pi}$ , then we are either embedded and conformal to the plane, isometric to a catenoid or isometric to Enneper’s minimal surface. In fact the technique of our proof shows that if we are conformal to the plane, then if n?≥ 3 and ${ \int_{\Sigma} | A|^{2}\leq 16 \pi }$ then Σ is embedded or Σ is the image of a generalized catenoid inverted at a point on the catenoid. In order to prove these theorems, we prove a Gauss–Bonnet theorem for surfaces with complete ends and isolated finite area singularities which extends a theorem of Jorge-Meeks (Topology 22(2):203–221, 1983). Using this theorem, we then prove an inversion formula for the Willmore energy.