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In the absence of replication of wells, empirical criteria for enzyme-linked immunospot (ELISpot) positivity use fixed differences or ratios between spot forming units (SFU) counts between test and control. We propose an alternative approach which first identifies the optimally variance-stabilizing transformation of the SFU counts, based on the Bland-Altman plot of the test and control wells. The second step is to derive a positivity threshold from the difference in between-plate distribution functions of the transformed test and control SFU counts. This method is illustrated using 1309 assay results from a cohort study of influenza in Vietnam in which some, but not all, of the peptide pools have clear tendencies for SFU counts to be higher in test than control wells., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Molecular characterization of the drug resistance of Mycobacterium tuberculosis strains with different origins can generate information that is useful for developing molecular methods. These methods are widely applicable for rapid detection of drug resistance. A total of 166 rifampin (RIF)- and/or isoniazid (INH)-resistant strains of M. tuberculosis have been isolated from different parts of Vietnam; they were screened for mutations associated with resistance to these drugs by sequence analysis investigating genetic mutations associated with RIF and INH resistance. Seventeen different mutations were identified in 74 RIF-resistant strains, 56 of which (approximately 76%) had mutations in the so-called 81-bp "hot-spot" region of the rpoB gene. The most common point mutations were in codons 531 (37.8%), 526 (23%), and 516 (9.46%) of the rpoB gene. Mutations were not found in three strains (4.05%). In the case of INH resistance, five different mutations in the katG genes of 82 resistant strains were detected, among which the nucleotide substitution at codon 315 (76.83%) is the most common mutation. This study provided the first molecular characterization of INH and RIF resistance of M. tuberculosis strains from Vietnam, and detection of the katG and rpoB mutations of the INH and RIF-resistant strains should be useful for rapid detection of the INH- and RIF-resistant strains by molecular tests.

This article reports the effects of nanometer surface roughness on the magnetic properties of CoFeHfO thin films, as deposited on Si (100) substrates. The surface roughness was controlled via the working pressure during the sputtering time. When the working pressure increases from 0.5 to 3 mT, the surface roughness (R) of CoFeHfO thin films, formed by islands with the average high R, increases from 0.25 nm to 4.66 nm, respectively. At surface roughness (R) = 4.66 nm, coercivity (H(c)) reaches the highest value of 0.42 Oe and magnetic anisotropy (H(k)) drops to the lowest value of 33 Oe. This suggests that the quality of the soft magnetic properties of thin film decrease due to the increase in surface roughness. However, at very low working pressure, thin films become a homogeneous structure which also exhibits poor soft magnetic properties. The optimum value, with H(c) of 0.10 Oe and H(k) of 50 Oe, were obtained at 1.5 mT of working pressure. The model of the roughness effect on the magnetic properties is introduced and discussed.

We report the first observation of a charm-strange meson D(+)(sJ)(2632) at a mass of 2632.5+/-1.7 MeV/c(2) in data from SELEX, the charm hadro-production experiment E781 at Fermilab. This state is seen in two decay modes, D(+)(s)eta and D0K+. In the D(+)(s)eta decay mode we observe a peak with 101 events over a combinatoric background of 54.9 events at a mass of 2635.4+/-3.3 MeV/c(2). There is a corresponding peak of 21 events over a background of 6.9 at 2631.5+/-2.0 MeV/c(2) in the decay mode D0K+. The decay width of this state is <17 MeV/c(2) at 90% confidence level. The relative branching ratio Gamma(D0K+)/Gamma(D(+)(s)eta) is 0.14+/-0.06. The mechanism that keeps this state narrow is unclear. Its decay pattern is also unusual, being dominated by the D(+)(s)eta decay mode.

We observe a signal for the doubly charmed baryon Xi(+)(cc) in the charged decay mode Xi(+)(cc)-->Lambda(+)(c)K-pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1+/-0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is 3519+/-1 MeV/c(2). The Gaussian mass width of this state is 3 MeV/c(2), consistent with resolution; its lifetime is less than 33 fs at 90% confidence.

We report new precision measurements of the lifetimes of the Lambda(+)(c) and D0 from SELEX, the charm hadroproduction experiment at Fermilab. Based upon 1630 Lambda(+)(c) and 10 210 D0 decays we observe lifetimes of tau[Lambda(+)(c)] = 198.1+/-7.0+/-5.6 fs and tau[D0] = 407.9+/-6.0+/-4.3 fs.

We report the first observation of the Cabibbo-suppressed charm baryon decay Ξ&#95;{c}^{+}→pK^{-}π^{+}. We observe 150±22±5 events for the signal. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 GeV/c Σ^{-} beam. The branching fractions of the decay relative to the Cabibbo-favored Ξ&#95;{c}^{+}→Σ^{+}K^{-}π^{+} and Ξ&#95;{c}^{+}→Ξ^{-}π^{+}π^{+} are measured to be B(Ξ&#95;{c}^{+}→pK^{-}π^{+})/B(Ξ&#95;{c}^{+}→Σ^{+}K^{-}π^{+})=0.22±0.06±0.03 and B(Ξ&#95;{c}^{+}→pK^{-}π^{+})/B(Ξ&#95;{c}^{+}→Ξ^{-}π^{+}π^{+})=0.20±0.04±0.02, respectively.