Preventing perinatal depression in low-income home visiting clients: A randomized controlled trial.

Objective: To assess the efficacy of a 6-week cognitive-behavioral intervention in preventing the onset of perinatal depression and reducing depressive symptoms among low-income women in home visitation programs. Method: Sixty-one women who were pregnant or who had a child less than 6 months of age and who were assessed as at risk for perinatal depression were randomized to a 6-week, group-based cognitive-behavioral intervention or usual home visiting services. Study participants were predominately African American, unmarried, and unemployed. Intervention sessions were led by a licensed clinical social worker or clinical psychologist. Home visitors provided 1-on-1 reinforcement of key intervention messages between group sessions. Depressive symptoms were measured with the Beck Depression Inventory–II (Beck, Steer, & Brown, 1996), and major depressive episodes were measured with the Maternal Mood Screener (MMS; Le & Mu?oz, 1998). Outcomes were assessed at baseline and at 1 week and 3 months postintervention. Results: Repeated measures analysis of variance indicated that there was a significant Time × Condition interaction, F(2, 112) = 4.1, p = .02. At 3 months postintervention, 9 of 27 (33%) women receiving usual care reported levels of depressive symptoms that met clinical cutoff for depression on the MMS compared with 3 of 32 (9%) women in the intervention condition, χ2(1, N = 59) = 5.18, p     

A coupled model tree (MT) genetic algorithm (GA) scheme for biofouling assessment in pipelines

A computerized learning algorithm was developed for assessing the extent of biofouling formations on the inner surfaces of water supply pipelines. Four identical pipeline experimental systems with four different types of inlet waters were set up as part of a large cooperative project between academia and industry in Israel on biofouling modeling, prediction, and prevention in pipeline systems. Samples were taken periodically for hydraulic, chemical, and biological analyses. Biofilm sampling was done using Robbins devices, carrying stainless steel coupons. An MT-GA, a hybrid model combining model trees (MTs) and genetic algorithms (GAs) in which the sampled input data are selected by the proposed methodology, was developed. The method outcome is a set of empirical linear rules which form a model tree, iteratively optimized by a GA and verified using the dataset resulting from the empirical field studies. Good correlations were achieved between modeled and observed cell coverage area within the biofilm. Sensitivity analysis was conducted by testing the model’s response to changes in: (1) the biofilm measure used as output (target) variable; (2) variability of GA parameters; and (3) input attributes. The proposed methodology provides a new tool for biofouling assessment in pipelines.     

Framework for using quantitative PCR as a nonculture based method to estimate virus infectivity

Measuring the efficiency of virus disinfection with quantitative PCR (qPCR) has been criticized as inadequate due to the production of false-positive signals. Such a claim, however, presupposes an understanding of the theoretical qPCR response. Many studies have assumed that the loss in qPCR signal upon disinfection should equal the loss in infectivity, without accounting for the fact that qPCR typically assays only a fraction of the viral genome. This study aimed to develop a theoretical framework to relate viral infectivity with genome damage measured by qPCR. The framework quantified damage to the entire genome based on the qPCR amplification of smaller sections, assuming single-hit inactivation and a Poissonian distribution of damage. The framework was tested and modified using UV(254) inactivation studies with bacteriophage MS2 (culturing and qPCR of approximately half the genome). Genome regions showed heterogeneous sensitivities to UV(254) treatment, thus deviating from the assumption of Poissonian damage. We offered two modifications to account for these deviations and confirmed that the qPCR-based framework accurately estimated virus infectivity. This framework offers the potential to monitor the infectivity of viruses that remain nonculturable (norovirus). While developed for UV(254)-inactivated virus, the framework should apply to any disinfection technique that causes inactivation via single genomic lesions.     

Association with natural organic matter enhances the sunlight-mediated inactivation of MS2 coliphage by singlet oxygen

MS2 coliphage, a surrogate for human enteric viruses, is inactivated by singlet oxygen (1O2) produced via sunlight-mediated excitation of natural organic matter (NOM) in surface waters. The 1O2 concentration within a NOM macromolecule or supramolecular assembly ([1O2]internal) is orders of magnitude higher than in the bulk solution ([1O2]bulk). In close proximity of NOM, MS2 is thus exposed to an elevated 1O2 concentration ([1O2]NOM), and inactivation is likely to be enhanced as compared to the bulk solution. In experiments using a solar simulator, we determined [1O2]bulk, [1O2]internal, as well as the association of MS2 with four NOMs (Fluka humic acid, FHA; Suwannee river humic acid, SRHA; Aldrich humic acid, AHA; Pony lake fulvic acid, PLFA), and studied their effect on the MS2 inactivation rate constant, k(obs), over a range of 1-25 mg NOM/L. The k(obs) values were modeled as the sum of the inactivation rate constants in close proximity to the NOM and in the bulk solution, assuming Langmuir-type adsorption of NOM onto MS2. FHA and SRHA exhibited 13-22 fold greater adsorption equilibrium constants than AHA and PLFA. Inactivation in the bulk solution contributed between 2% (20 mg/L FHA) and 39% (5 mg/L AHA) toward the overall k(obs). Thus, even for the less adsorbing NOM, inactivation was dominated by [1O2]NOM rather than [1O2]bulk. Changes in solution chemistry to promote closer interactions between MS2 and NOM also enhanced k(obs). Addition of Mg2+ to neutralize the negative surface charge of MS2 and NOM increased k(obs) up to 4.1-fold. Similarly, lowering the solution pH closer to the isoelectric point of MS2 (pl = 3.9) enhanced k(ob), 51-fold in 5 mg/L AHA.     

Contribution of coexisting sulfate and iron reducing bacteria to methylmercury production in freshwater river sediments

We investigated microbial methylmercury (CH(3)Hg) production in sediments from the South River (SR), VA, an ecosystem contaminated with industrial mercury (Hg). Potential Hg methylation rates in samples collected at nine sites were low in late spring and significantly higher in late summer. Demethylation of (14)CH(3)Hg was dominated by (14)CH(4) production in spring, but switched to producing mostly (14)CO(2) in the summer. Fine-grained sediments originating from the erosion of river banks had the highest CH(3)Hg concentrations and were potential hot spots for both methylation and demethylation activities. Sequencing of 16S rRNA genes of cDNA recovered from sediment RNA extracts indicated that at least three groups of sulfate-reducing bacteria (SRB) and one group of iron-reducing bacteria (IRB), potential Hg methylators, were active in SR sediments. SRB were confirmed as a methylating guild by amendment experiments showing significant sulfate stimulation and molybdate inhibition of methylation in SR sediments. The addition of low levels of amorphous iron(III) oxyhydroxide significantly stimulated methylation rates, suggesting a role for IRB in CH(3)Hg synthesis. Overall, our studies suggest that coexisting SRB and IRB populations in river sediments contribute to Hg methylation, possibly by temporally and spatially separated processes.     

Green tea catechins as brain-permeable, natural iron chelators-antioxidants for the treatment of neurodegenerative disorders

Neurodegeneration in Parkinson's, Alzheimer's, or other neurodegenerative diseases appears to be multifactorial, where a complex set of toxic reactions, including oxidative stress (OS), inflammation, reduced expression of trophic factors, and accumulation of protein aggregates, lead to the demise of neurons. One of the prominent pathological features is the abnormal accumulation of iron on top of the dying neurons and in the surrounding microglia. The capacity of free iron to enhance and promote the generation of toxic reactive oxygen radicals has been discussed numerous times. The observations that iron induces aggregation of inert alpha-synuclein and beta-amyloid peptides to toxic aggregates have reinforced the critical role of iron in OS-induced pathogenesis of neurodegeneration, supporting the notion that a combination of iron chelation and antioxidant therapy may be one significant approach for neuroprotection. Tea flavonoids (catechins) have been reported to possess divalent metal chelating, antioxidant, and anti-inflammatory activities, to penetrate the brain barrier and to protect neuronal death in a wide array of cellular and animal models of neurological diseases. This review aims to shed light on the multipharmacological neuroprotective activities of green tea catechins with special emphasis on their brain-permeable, nontoxic, transitional metal (iron and copper)-chelatable/radical scavenger properties.     

Reactivity of substituted benzotrichlorides toward granular iron, Cr(II), and an iron(II) porphyrin: A correlation analysis

Cross-correlations of rate constants between a system of interest and a better-defined one have become popular as a tool in studying transformations of organic pollutants. A slope of unity (if the correlation is conducted on a log-log basis) in such plots has been invoked as evidence of a common mechanism. To explore this notion, benzotrichloride and several of its substituted analogues were reacted with Cr(H2O)6(2+), an iron(II) porphyrin (iron meso-tetra(4-carboxyphenyl)porphine chloride, Fe(II)TCP), and granular iron. The first two reductants react with organohalides by dissociative inner sphere single-electron transfer, while mechanism(s) for organohalide reduction by granular iron are still debated. Apartfrom sterically hindered compounds, good correlations were obtained in comparing any two systems, although slopes (on a log-log basis) deviated from unity. We argue that a slope of unity is neither necessary nor sufficient evidence of a common mechanism. Overall rate constants may be composite entities, consisting in part of rate or equilibrium constants for adsorption onto surfaces or for precursor formation in solution; these components may differ between systems in their susceptibility to substituent effects. Cross-correlations may prove useful in predicting reactivity in the absence of steric effects, but additional evidence is required in deducing reaction mechanisms.     

Photoinactivation of virus on iron-oxide coated sand: enhancing inactivation in sunlit waters

Adsorption onto iron oxides can enhance the removal of waterborne viruses in constructed wetlands and soils. If reversible adsorption is not coupled with inactivation, however, infective viruses may be released when changes in solution conditions cause desorption. The goals of this study were to investigate the release of infective bacteriophages MS2 and ΦX174 (two human viral indicators) after adsorption onto an iron oxide coated sand (IOCS), and to promote viral inactivation by exploiting the photoreactive properties of the IOCS. The iron oxide coating greatly enhanced viral adsorption (adsorption densities up to ∼10⁹ infective viruses/g IOCS) onto the sand, but had no affect on infectivity. Viruses that were adsorbed onto IOCS under control conditions (pH 7.5, 10 mM Tris, 1250 μS/cm) were released into solution in an infective state with increases in pH and humic acid concentrations. The exposure of IOCS-adsorbed MS2 to sunlight irradiation caused significant inactivation via a photocatalytic mechanism in both buffered solutions and in wastewater samples (4.9 log₁₀ and 3.3 log₁₀ inactivation after 24-h exposure, respectively). Unlike MS2, ΦX174 inactivation was not enhanced by photocatalysis. In summary, IOCS enhanced the separation of viruses from the water column, and additionally provided a photocatalytic mechanism to promote inactivation of one of the surrogates studied. These qualities make it an attractive option for improving viral control strategies in constructed wetlands.