Identification of a chemical fingerprint linking the undeclared 2017 release of 106Ru to advanced nuclear fuel reprocessing

The undeclared release and subsequent detection of ruthenium-106 (106Ru) across Europe from late September to early October of 2017 prompted an international effort to ascertain the circumstances of the event. While dispersion modeling, corroborated by ground deposition measurements, has narrowed possible locations of origin, there has been a lack of direct empirical evidence to address the nature of the release. This is due to the absence of radiological and chemical signatures in the sample matrices, considering that such signatures encode the history and circumstances of the radioactive contaminant. In limiting cases such as this, we herein introduce the use of selected chemical transformations to elucidate the chemical nature of a radioactive contaminant as part of a nuclear forensic investigation. Using established ruthenium polypyridyl chemistry, we have shown that a small percentage (1.2 ± 0.4%) of the radioactive 106Ru contaminant exists in a polychlorinated Ru(III) form, partly or entirely as β-106RuCl3, while 20% is both insoluble and chemically inert, consistent with the occurrence of RuO2, the thermodynamic endpoint of the volatile RuO4. Together, these findings present a clear signature for nuclear fuel reprocessing activity, specifically the reductive trapping of the volatile and highly reactive RuO4, as the origin of the release. Considering that the previously established 103Ru:106Ru ratio indicates that the spent fuel was unusually young with respect to typical reprocessing protocol, it is likely that this exothermic trapping process proved to be a tipping point for an already turbulent mixture, leading to an abrupt and uncontrolled release

Four-loop beta function and mass anomalous dimension in Dimensional Reduction

Within the framework of QCD we compute renormalization constants for the strong coupling and the quark masses to four-loop order. We apply the DR-bar scheme and put special emphasis on the additional couplings which have to be taken into account. This concerns the epsilon-scalar--quark Yukawa coupling as well as the vertex containing four epsilon-scalars. For a supersymmetric Yang Mills theory, we find, in contrast to a previous claim, that the evanescent Yukawa coupling equals the strong coupling constant through three loops as required by supersymmetry.Comment: 15 pages, fixed typo in Eq. (18

Exact N3LO results for qq ′ → H + X

We compute the contribution to the total cross section for the inclusive production of a Standard Model Higgs boson induced by two quarks with different flavour in the initial state. Our calculation is exact in the Higgs boson mass and the partonic center-of-mass energy. We describe the reduction to master integrals, the construction of a canonical basis, and the solution of the corresponding differential equations. Our analytic result contains both Harmonic Polylogarithms and iterated integrals with additional letters in the alphabet. © 2015, The Author(s)

Semileptonic b --> u decays: lepton invariant mass spectrum

We compute O(alpha_s^2) QCD corrections to the lepton invariant mass spectrum in the decay b --> u l nu_l, relevant for the determination of the CKM matrix element |V_{ub}|. Our method can also be used to evaluate moments of the lepton energy distribution with an O(alpha_s^2) accuracy. The abelian part of our result gives the neutrino invariant mass spectrum in the muon decay and, upon integration, the O(alpha^2) correction to the muon lifetime.Comment: 5 pages, revte

Four-Loop Decoupling Relations for the Strong Coupling

We compute the matching relation for the strong coupling constant within the framework of QCD up to four-loop order. This allows a consistent five-loop running (once the $\beta$ function is available to this order) taking into account threshold effects. As a side product we obtain the effective coupling of a Higgs boson to gluons with five-loop accuracy.Comment: 11 page

Towards Higgs boson production in gluon fusion to NNLO in the MSSM

We consider the Higgs boson production in the gluon-fusion channel to next-to-next-to-leading order within the Minimal Supersymmetric Standard Model. In particular, we present analytical results for the matching coefficient of the effective theory and study its influence on the total production cross section in the limit where the masses of all MSSM particles coincide. For supersymmetric masses below 500 GeV it is possible to find parameters leading to a significant enhancement of the Standard Model cross section, the $K$-factors, however, change only marginally.Comment: 20 pages; v2: modification of discussion of numerical effect, version to appear in EPJC; v3: eq.(18) corrected, minor correction

Macrophage/fibroblast coculture induces macrophage inflammatory protein‐1a production mediated by intercellular adhesion molecule‐1 and oxygen radicals

This study examined the cell‐to‐cell interaction between fibroblasts and macrophages as a possible contributor to the chronic inflammatory state. In a coculture system, consisting of macrophages layered over confluent fibroblasts, there was a significant increase in macrophage inflammatory protein 1α (MIP‐1α) compared with control cultures. ICAM‐1 adhesion was identified as an important stimulus of MIP‐1α production by using ICAM‐1‐specific monoclonal antibodies. Furthermore, fibroblasts from ICAM‐1 knockout mice induced significantly less MIP‐1α production from peritoneal macrophages when compared to control fibroblasts. In addition, it appeared that oxygen radicals functioned as activating molecules during cellular interaction and production of MIP‐1α, as the addition of the antioxidant N‐acetylcysteine (NAC) prevented MIP‐1α secretion. Thus, the ICAM‐1 and oxygen radical‐mediated induction of MIP‐1α associated with a macrophage/fibroblast coculture system provides one possible mechanism by which immune/inflammatory cell interactions may augment chemokine production and exacerbate chronic inflammatory diseases. J. Leukoc. Biol. 64: 636–641; 1998.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141120/1/jlb0636.pd

Reconstruction of metabolic networks from high-throughput metabolite profiling data: in silico analysis of red blood cell metabolism

We investigate the ability of algorithms developed for reverse engineering of transcriptional regulatory networks to reconstruct metabolic networks from high-throughput metabolite profiling data. For this, we generate synthetic metabolic profiles for benchmarking purposes based on a well-established model for red blood cell metabolism. A variety of data sets is generated, accounting for different properties of real metabolic networks, such as experimental noise, metabolite correlations, and temporal dynamics. These data sets are made available online. We apply ARACNE, a mainstream transcriptional networks reverse engineering algorithm, to these data sets and observe performance comparable to that obtained in the transcriptional domain, for which the algorithm was originally designed.Comment: 14 pages, 3 figures. Presented at the DIMACS Workshop on Dialogue on Reverse Engineering Assessment and Methods (DREAM), Sep 200

Strong Coupling Constant with Flavour Thresholds at Four Loops in the MS-bar Scheme

We present in analytic form the matching conditions for the strong coupling constant alpha_s^(n_f)(mu) at the flavour thresholds to three loops in the modified minimal-subtraction scheme. Taking into account the recently calculated coefficient beta_3 of the Callan-Symanzik beta function of quantum chromodynamics, we thus derive a four-loop formula for alpha_s^(n_f)(mu) together with appropriate relationships between the asymptotic scale parameters Lambda^(n_f) for different numbers of flavours n_f.Comment: 10 pages (Latex), 3 figures (Postscript