An FeV(O) complex has been synthesized from equimolar solutions of (Et4N)2[FeIII(Cl)(biuret-amide)] and mCPBA in CH3CN at room temperature. The FeV(O) complex has been characterized by UV–vis, EPR, Mössbauer, and HRMS and shown to be capable of oxidizing a series of alkanes having C–H bond dissociation energies ranging from 99.3 kcal mol−1 (cyclohexane) to 84.5 kcal mol−1 (cumene). Linearity in the Bell–Evans–Polayni graph and the finding of a large kinetic isotope effect suggest that hydrogen abstraction is engaged the rate-determining step.

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This study determined the utility of a panel of serum fibrosis markers along with routine laboratory tests in estimating the likelihood of histological cirrhosis in a cohort of prior nonresponders with chronic hepatitis C. The relationship between serum markers and quantitative hepatic collagen content was also determined. Liver biopsy samples from 513 subjects enrolled in the HALT-C trial were assigned Ishak fibrosis scores. The collagen content of 386 sirius-red stained, nonfragmented biopsy samples was quantified using computerized morphometry. Serum tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), amino-terminal peptide of type III procollagen (PIIINP), hyaluronic acid (HA), and YKL-40 levels were determined using commercially available assays.Sixty-two percent of patients had noncirrhotic fibrosis (Ishak stage 2-4) whereas 38% had cirrhosis (

The effect of nonionic polyoxyethylene (POE) surfactants on the solubilization rate of individual polycyclic aromatic hydrocarbons (PAHs) from a weathered, coal tar-contaminated soil obtained from a manufactured gas plant (MGP) site was studied. The release of PAHs upon surfactant washing were measured with time. Time-varying adsorption of PAHs to Tenax resin was also studied. Because of its large sorption coefficients for organic solutes, Tenax maintained near-zero concentrations of aqueous PAHs, thereby maximizing transfer of PAHs at the soil-water interface. The release of PAHs from the MGP soil exhibited a nonequilibrium behavior, typical of such soils. Surfactants significantly enhanced the rate of PAH solubilization, the amount solubilized being dependent upon the structure of the surfactant. It is postulated that the enhancement of PAH release by surfactants occurs by two mechanisms: (1) micellar solubilization by increased concentration gradient at the soil/tar-water interface and (2) sorption and penetration of surfactant molecules, causing intrasorbent swelling of the soil-tar matrix and increased matrix diffusivity of PAHs. A modified radial diffusion model was used to evaluate the relative importance of these mechanisms in surfactant washing of contaminated soils. It was concluded that surfactants enhanced PAH release from the test soil mainly by increasing matrix diffusivities, while increase in solubility by partitioning of PAHs into the micellar pseudophase played a secondary role.

A ribonucleotide reductase (RNR) from Flavobacterium johnsoniae ( Fj) differs fundamentally from known (subclass a-c) class I RNRs, warranting its assignment to a new subclass, Id. Its β subunit shares with Ib counterparts the requirements for manganese(II) and superoxide (O) for activation, but it does not require the O-supplying flavoprotein (NrdI) needed in Ib systems, instead scavenging the oxidant from solution. Although Fj β has tyrosine at the appropriate sequence position (Tyr 104), this residue is not oxidized to a radical upon activation, as occurs in the Ia/b proteins. Rather, Fj β directly deploys an oxidized dimanganese cofactor for radical initiation. In treatment with one-electron reductants, the cofactor can undergo cooperative three-electron reduction to the II/II state, in contrast to the quantitative univalent reduction to inactive "met" (III/III) forms seen with I(a-c) βs. This tendency makes Fj β unusually robust, as the II/II form can readily be reactivated. The structure of the protein rationalizes its distinctive traits. A distortion in a core helix of the ferritin-like architecture renders the active site unusually open, introduces a cavity near the cofactor, and positions a subclass-d-specific Lys residue to shepherd O to the Mn cluster. Relative to the positions of the radical tyrosines in the Ia/b proteins, the unreactive Tyr 104 of Fj β is held away from the cofactor by a hydrogen bond with a subclass-d-specific Thr residue. Structural comparisons, considered with its uniquely simple mode of activation, suggest that the Id protein might most closely resemble the primordial RNR-β.