552 research outputs found

    Mesoscopic transport beyond linear response

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    We present an approach to steady-state mesoscopic transport based on the maximum entropy principle formulation of nonequilibrium statistical mechanics. Our approach is not limited to the linear response regime. We show that this approach yields the quantization observed in the integer quantum Hall effect at large currents, which until now has been unexplained. We also predict new behaviors of non-local resistances at large currents in the presence of dirty contacts.Comment: 14 pages plus one figure (with an insert) (post-script codes appended), RevTeX 3.0, UCF-CM-93-004 (Revised

    Comparison of ibuprofen release from minitablets and capsules containing ibuprofen: β-Cyclodextrin complex

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    NOTICE: this is the author’s version of a work that was accepted for publication in European Journal of Pharmaceutics and Biopharmaceutics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Eur J Pharm Biopharm. 2011 May;78(1):58-66. Epub 2010 Dec 30.Mixtures containing ibuprofen (IB) complexed with b-cyclodextrin (bCD) obtained by two complexation methods [suspension/solution (with water removed by air stream, spray- and freeze-drying) and kneading technique] were processed into pharmaceutical dosage forms (minitablets and capsules). Powders (IB, bCD and IBbCD) were characterized for moisture content, densities (true and bulk), angle of repose and Carr’s index, X-ray and NMR. From physical mixtures and IBbCD complexes without other excipients were prepared 2.5-mm-diameter minitablets and capsules. Minitablets were characterized for the energy of compaction, tensile strength, friability, density and IB release (at pH 1.0 and 7.2), whereby capsules were characterized for IB release. The results from the release of IB were analyzed using different parameters, namely, the similarity factor (f2), the dissolution efficiency (DE) and the amounts released at a certain time (30, 60 and 180 min) and compared statistically (a = 0.05). The release of IB from the minitablets showed no dependency on the amount of water used in the formation of the complexes. Differences were due to the compaction force used or the presence of a shell for the capsules. The differences observed were mostly due to the characteristics of the particles (dependent on the method considered on the formation of the complexes) and neither to the dosage form nor to the complex of the IB

    Studies on Homalomeneae (Araceae) of Borneo VIII: Delimitation of additional informal suprageneric taxa for Sundaic Homalomena

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    One new informal Supergroup and eight informal species' Complexes are proposed for Sundaic Homalomena (Araceae: Homalomeneae). Defining characters are enumerated and illustrated, and keys to all informal groups provided

    Advances in quadrupole and time-of-flight mass spectrometry for peptide MRM based translational research analysis

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    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The application of unit resolution tandem quadrupole and high-resolution orthogonal acceleration ToF mass spectrometers for the quantitation and translational analysis of proteolytic peptides is described. The MS platforms were contrasted in terms of sensitivity and linear response. Moreover, the selectivity of the platforms was investigated and the effect on quantitative precision studied. Chromatographic LC conditions, including gradient length and configuration, were investigated with respect to speed/throughput, while minimizing isobaric interferences, thereby providing information with regard to practical sample cohort size limitations of LC-MS for large cohort experiments. In addition to these fundamental analytical performance metrics, precision and linear dynamic ranges were also studied. An LC-MS configuration that encompasses the best combination of throughput and analytical accuracy for translational studies was chosen, despite the MS platforms giving similar quantitative performance, and instances were identified where alternative combinations were found to be beneficial. This configuration was utilized to demonstrate that proteolytically digested nondepleted samples from heart failure patients could be classified with good discriminative power using a subset of proteins previously suggested as candidate biomarkers for cardiovascular diseases

    Search for the decay K+π+ννˉK^+\to \pi^+ \nu \bar\nu in the momentum region Pπ<195 MeV/cP_\pi < 195 {\rm ~MeV/c}

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    We have searched for the decay K+π+ννˉK^+ \to \pi^+ \nu \bar\nu in the kinematic region with pion momentum below the K+π+π0K^+ \to \pi^+ \pi^0 peak. One event was observed, consistent with the background estimate of 0.73±0.180.73\pm 0.18. This implies an upper limit on B(K+π+ννˉ)<4.2×109B(K^+ \to \pi^+ \nu \bar\nu)< 4.2\times 10^{-9} (90% C.L.), consistent with the recently measured branching ratio of (1.570.82+1.75)×1010(1.57^{+1.75}_{-0.82}) \times 10^{-10}, obtained using the standard model spectrum and the kinematic region above the K+π+π0K^+ \to \pi^+ \pi^0 peak. The same data were used to search for K+π+X0K^+ \to \pi^+ X^0, where X0X^0 is a weakly interacting neutral particle or system of particles with 150<MX0<250 MeV/c2150 < M_{X^0} < 250 {\rm ~MeV/c^2}.Comment: 4 pages, 2 figure

    SPACA3gene variants in a New Zealand cohort of infertile and fertile couples

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    SPRASA (also referred to as SLLP1) is a protein identified in the acrosome of human sperm and encoded by the gene SPACA3. SPRASA is associated with sperm-oocyte recognition and binding, and may play a role in fertility. In order to determine whether variants in the SPACA3 gene are associated with human infertility, we undertook a genetic analysis of 102 infertile and 104 fertile couples. Three gene variants were identified using PCR-based DNA sequencing; 1) an insertion of TGC within a quadruple tri-nucleotide (TGC) repeat region in the 5’ untranslated region (UTR) (g.–22TGC(4_5), 2) a guanine to adenosine transition at position 239 (c.239G> A) resulting in a non-synonymous amino acid substitution from cysteine to tyrosine (p.C80Y) at position 80 in the putative transmembrane region, and 3) a novel nucleotide variant (c.691G> C) located in the 3’UTR. A functional effect of the g.–22TGC (4_5) was confirmed by a luciferase expression assay, while the effects of the variants c.239G> A and c.691G> C were predicted using in silico analysis. Although the frequencies of these variants were not significantly different between the infertile and fertile populations, we present evidence that the variants could affect the expression levels or function of SPRASA, thereby affecting a couple's fertility. Larger populations, especially individuals/couples with unexplained infertility, need to be screened for these variants to validate a relationship with fertility

    Phylogeny of asian homalomena (Araceae) based on the its region combined with morphological and chemical data

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    A phylogenetic analysis of the genus Homalomena (Araceae: Homalomeneae) based on the nITS region is presented. Eighty-nine taxa are included; representing all Asian supergroups, several Neotropical species currently assigned to Homalomena, and selected species of Philodendron. Asian Homalomena is well supported as monophyletic and excludes Neotropical Homalomena. The Cyrtocladon supergroup is monophyletic after transferring the Insignis complex and Havilandii complex into the Punctulata supergroup. The Homalomena and Chamaecladon supergroups are well supported. A reduced phylogeny of 20 accessions representing 15 taxa was used for subsequent morphological and chemical marker optimization. A constricted spathe and four stamens per staminate flower are plesiomorphic for Homalomena. Staminodes among the pistillate zone are lost three times independently in Homalomena supergroup, Punctulata supergroup, and H. vivens. Chemical markers identified from liquid chromatography-mass spectroscopy profiling provided an independent set of markers that further support the separation of Neotropical species of Homalomena from the Asian taxon. Three chemical markers at Rt 2.55 min, 2.69 min, and 2.90 min are shared among the majority of taxa sampled for Asian Homalomena, and Neotropical species currently assigned to Homalomena show two unique peaks at Rt 3.25 min and 3.54 min. Five chemical markers support the Cyrtocladon supergroup with the exception of Homalomena vivens. A chemical marker at Rt 3.60 min is plesiomorphic for the Chamaecladon, Homalomena and Punctulata supergroups. A chemical marker at Rt 2.80 min is apomorphic for the Chamaecladon supergroup, with a separate gain in H. punctulata. This study supports removal of the Neotropical species from Homalomena, redefines the morphological boundaries of Homalomena sensu stricto (i.e. the Asian species), and supports and refines the grouping of Asian species into supergroups

    Production and Decay of D_1(2420)^0 and D_2^*(2460)^0

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    We have investigated D+πD^{+}\pi^{-} and D+πD^{*+}\pi^{-} final states and observed the two established L=1L=1 charmed mesons, the D1(2420)0D_1(2420)^0 with mass 242122+1+22421^{+1+2}_{-2-2} MeV/c2^{2} and width 2053+6+320^{+6+3}_{-5-3} MeV/c2^{2} and the D2(2460)0D_2^*(2460)^0 with mass 2465±3±32465 \pm 3 \pm 3 MeV/c2^{2} and width 2876+8+628^{+8+6}_{-7-6} MeV/c2^{2}. Properties of these final states, including their decay angular distributions and spin-parity assignments, have been studied. We identify these two mesons as the jlight=3/2j_{light}=3/2 doublet predicted by HQET. We also obtain constraints on {\footnotesize ΓS/(ΓS+ΓD)\Gamma_S/(\Gamma_S + \Gamma_D)} as a function of the cosine of the relative phase of the two amplitudes in the D1(2420)0D_1(2420)^0 decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by sending mail to: [email protected]

    Measurement of the branching fraction for Υ(1S)τ+τ\Upsilon (1S) \to \tau^+ \tau^-

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    We have studied the leptonic decay of the Υ(1S)\Upsilon (1S) resonance into tau pairs using the CLEO II detector. A clean sample of tau pair events is identified via events containing two charged particles where exactly one of the particles is an identified electron. We find B(Υ(1S)τ+τ)=(2.61 ± 0.12 +0.090.13)B(\Upsilon(1S) \to \tau^+ \tau^-) = (2.61~\pm~0.12~{+0.09\atop{-0.13}})%. The result is consistent with expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS 94/1297, CLEO 94-20 (submitted to Physics Letters B
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