Synthesis and characterization of several cesium zirconates and a study of their relevance to fission product chemistry

Investigations of the reaction of CsI with excess ZrO(,2) in various containers at 400-850(DEGREES)C have successfully demonstrated the formation of ZrI(,4) and Cs(,2)ZrO(,3) in low yields (\u3c35%) based upon the analytical evidence from X-ray fluorescence and atomic absorption techniques;To further investigate the chemistry, macroscopic amounts of the cesium zirconates have been synthesized from reactions of Cs-Zr-O(,2) in silver crucibles or of Cs-CsO(,2)-ZrO(,2) and CsO(,2)-Zr in welded silver tubing at 600-750(DEGREES)C for one to two weeks. These reactions have produced four new compounds: Cs(,2)ZrO(,3) and Cs(,4)ZrO(,4) each in 95-100% yield, and two evidently ZrO(,2)-richer cesium zirconates of unknown composition and structure in 40-50% yield;The crystal structures of the first two phases have been solved by single crystal methods. The Cs(,2)ZrO(,3) is structurally related to K(,2)ZrO(,3) or Cs(,2)PrO(,3) and crystallizes in the orthorhombic space group Cmcm with a = 11.256(6), b = 7.738(5) and c = 5.967(7) (ANGSTROM), Z = 4 (R = 5.2%). Its structure consists of infinite chains along the c-axis formed by square pyramidal Zr(O)O(,4/2) units sharing opposite basal edges and represents the second zirconate reported with five-coordinate zirconium. The compound Cs(,4)ZrO(,4) crystallizes in the monoclinic space group P2(,1)/c with a = 7.163(1), b = 19.919(2), c = 7.158(1) (ANGSTROM) and (beta) = 103.05(8)(DEGREES), Z = 4 (R = 3.2%). The structure contains isolated and slightly distorted tetrahedral ZrO(,4) units. The third zirconate crystallizes in a triclinic cell with a = 10.254(1), b = 10.416(2), c = 10.104(1) (ANGSTROM), (alpha) = 106.45(1)(DEGREES), (beta) = 98.51(1)(DEGREES), and (gamma) = 100.17(1)(DEGREES). Volume relationships suggest a composition near 3Cs(,2)O(.)7ZrO(,2). The fourth zirconate evidently crystallizes with a monoclinic cell, a = 9.926(5), b = 15.359(8), c = 20.642(8) (ANGSTROM), (beta) = 103.28(3)(DEGREES);The thermal stabilities of Cs(,2)ZrO(,3) and Cs(,4)ZrO(,4) have been investigated both in vacuo and in sealed silver containers. The compounds Cs(,2)ZrO(,3) and Cs(,4)ZrO(,4) decompose into Cs(,2)O and ZrO(,2) or Cs(,2)ZrO(,3) at near 915(DEGREES)C and 260-280(DEGREES)C under high vacuum, whereas in sealed silver containers they are stable to above 900(DEGREES)C and to 730 (+OR-) 20(DEGREES)C, respectively. The relevance of the formation and properties;of these zirconates to the distribution of fission products is also discussed; *DOE Report IS-T-1253. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy

Direct Observation of Long-Term Durability of Superconductivity in YBa2_2Cu3_3O7_7-Ag2_2O Composites

We report direct observation of long-term durability of superconductivity of several YBa$_2$Cu$_3$O$_7$-Ag$_2$O composites that were first prepared and studied almost 14 years ago [J. J. Lin {\it et al}., Jpn. J. Appl. Phys. {\bf 29}, 497 (1990)]. Remeasurements performed recently on both resistances and magnetizations indicate a sharp critical transition temperature at 91 K. We also find that such long-term environmental stability of high-temperature superconductivity can only be achieved in YBa$_2$Cu$_3$O$_7$ with Ag$_2$O addition, but not with pure Ag addition.Comment: to be published in Jpn. J. Appl. Phy

Inequalities Detecting Quantum Entanglement for 2⊗d2\otimes d Systems

We present a set of inequalities for detecting quantum entanglement of $2\otimes d$ quantum states. For $2\otimes 2$ and $2\otimes 3$ systems, the inequalities give rise to sufficient and necessary separability conditions for both pure and mixed states. For the case of $d>3$, these inequalities are necessary conditions for separability, which detect all entangled states that are not positive under partial transposition and even some entangled states with positive partial transposition. These inequalities are given by mean values of local observables and present an experimental way of detecting the quantum entanglement of $2\otimes d$ quantum states and even multi-qubit pure states.Comment: 6 page

Apoptosis signal-regulating kinase 1 mediates denbinobin-induced apoptosis in human lung adenocarcinoma cells

In the present study, we explore the role of apoptosis signal-regulating kinase 1 (ASK1) in denbinobin-induced apoptosis in human lung adenocarcinoma (A549) cells. Denbinobin-induced cell apoptosis was attenuated by an ASK1 dominant-negative mutant (ASK1DN), two antioxidants (N-acetyl-L-cysteine (NAC) and glutathione (GSH)), a c-Jun N-terminal kinase (JNK) inhibitor (SP600125), and an activator protein-1 (AP-1) inhibitor (curcumin). Treatment of A549 cells with denbinobin caused increases in ASK1 activity and reactive oxygen species (ROS) production, and these effects were inhibited by NAC and GSH. Stimulation of A549 cells with denbinobin caused JNK activation; this effect was markedly inhibited by NAC, GSH, and ASK1DN. Denbinobin induced c-Jun phosphorylation, the formation of an AP-1-specific DNA-protein complex, and Bim expression. Bim knockdown using a bim short interfering RNA strategy also reduced denbinobin-induced A549 cell apoptosis. The denbinobin-mediated increases in c-Jun phosphorylation and Bim expression were inhibited by NAC, GSH, SP600125, ASK1DN, JNK1DN, and JNK2DN. These results suggest that denbinobin might activate ASK1 through ROS production to cause JNK/AP-1 activation, which in turn induces Bim expression, and ultimately results in A549 cell apoptosis

Autonomic Dysfunction Because of Severe Tetanus in an Unvaccinated Child

Tetanus is rare in a country with a national vaccination program. When it does occur, the associated autonomic dysfunction is a challenge for physicians. We report here a case of an unvaccinated 5-year-old boy who suffered from tetanus complicated by autonomic dysfunction, which was successfully controlled by the infusion of magnesium sulfate. This is the first case that demonstrated the therapeutic effect of magnesium sulfate in a child with tetanus. This case highlights the importance of implementing a vaccination program

Aciculatin inhibits lipopolysaccharide-mediated inducible nitric oxide synthase and cyclooxygenase-2 expression via suppressing NF-κB and JNK/p38 MAPK activation pathways

<p>Abstract</p> <p>Objectives</p> <p>Natural products have played a significant role in drug discovery and development. Inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been suggested to connect with various inflammatory diseases. In this study, we explored the anti-inflammatory potential of aciculatin (8-((2<it>R</it>,4<it>S</it>,5<it>S</it>,6<it>R</it>)-tetrahydro-4,5-dihydroxy-6-methyl-2<it>H</it>-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4<it>H</it>-chromen-4-one), one of main components of <it>Chrysopogon aciculatis</it>, by examining its effects on the expression and activity of iNOS and COX-2 in lipopolysaccharide (LPS)-activated macrophages.</p> <p>Methods</p> <p>We used nitrate and prostaglandin E₂(PGE₂) assays to examine inhibitory effect of aciculatin on nitric oxide (NO) and PGE₂levels in LPS-activated mouse RAW264.7 macrophages and further investigated the mechanisms of aciculatin suppressed LPS-mediated iNOS/COX-2 expression by western blot, RT-PCR, reporter gene assay and confocal microscope analysis.</p> <p>Results</p> <p>Aciculatin remarkably decreased the LPS (1 μg/mL)-induced mRNA and protein expression of iNOS and COX-2 as well as their downstream products, NO and PGE₂respectively, in a concentration-dependent manner (1-10 μM). Such inhibition was found, via immunoblot analyses, reporter gene assays, and confocal microscope observations that aciculatin not only acts through significant suppression of LPS-induced NF-κB activation, an effect highly correlated with its inhibitory effect on LPS-induced IκB kinase (IKK) activation, IκB degradation, NF-κB phosphorylation, nuclear translocation and binding of NF-κB to the κB motif of the iNOS and COX-2 promoters, but also suppressed phosphorylation of JNK/p38 mitogen-activated protein kinases (MAPKs).</p> <p>Conclusion</p> <p>Our results demonstrated that aciculatin exerts potent anti-inflammatory activity through its dual inhibitory effects on iNOS and COX-2 by regulating NF-κB and JNK/p38 MAPK pathways.</p