Performance Evaluation of a Full-Scale Deep U-Tube Utilizing Ozonated Oxygen as the Process Gas for Treating Drinking Water

A deep U-tube for treating drinking water is composed of a coaxial inner tube serving as an efficient concurrent down-flow ozone dissolver and an outer column carrying out reactions between ozone and organic substances dissolved in the water after sedimentation treatment. In the present study, we developed a novel simulation model of the U-tube reactor, assuming that the U-tube is composed of a plug flow section (inner tube) followed by a tanks-in-series section (outer bubble column) and taking into account the reactions involved, and the effects of the hydrostatic pressurization on the flow and absorption equilibrium for the ozone and inactive gases in developing the mass balance models. We constructed an algorithm to evaluate the U-tube reactor performance based on the mass balance models. The hydrodynamics and mass transfer characteristics in the inner tube were measured and their correlations were incorporated in the simulation model. Available literature data and correlations on the rates of reactions between ozone and organic substances, the gas-liquid equilibrium for the active and inactive gases and the fluid mixing properties are also incorporated in the simulation model. The simulation results well explained the available data on the ozone absorption efficiency and the removal efficiency of odorous material (2-MIB) in a pilot plant and a real U-tube reactor. It is found that the ozone absorption is practically a single function of the gas/liquid ratio, while the decomposition efficiency of 2-MIB is a single function of the ozone dose for the water quantity to be treated

Swelling of acetylated wood in organic liquids

To investigate the affinity of acetylated wood for organic liquids, Yezo spruce wood specimens were acetylated with acetic anhydride, and their swelling in various liquids were compared to those of untreated specimens. The acetylated wood was rapidly and remarkably swollen in aprotic organic liquids such as benzene and toluene in which the untreated wood was swollen only slightly and/or very slowly. On the other hand, the swelling of wood in water, ethylene glycol and alcohols remained unchanged or decreased by the acetylation. Consequently the maximum volume of wood swollen in organic liquids was always larger than that in water. The effect of acetylation on the maximum swollen volume of wood was greater in liquids having smaller solubility parameters. The easier penetration of aprotic organic liquids into the acetylated wood was considered to be due to the scission of hydrogen bonds among the amorphous wood constituents by the substitution of hydroxyl groups with hydrophobic acetyl groups.Comment: to be published in J Wood Science (Japanese wood research society

Mutagenicity of tamoxifen DNA adducts in human endometrial cells and in silico prediction of p53 mutation hotspots

Tamoxifen elevates the risk of endometrial tumours in women and α-(N2-deoxyguanosinyl)-tamoxifen adducts are reportedly present in endometrial tissue of patients undergoing therapy. Given the widespread use of tamoxifen there is considerable interest in elucidating the mechanisms underlying treatment-associated cancer. Using a combined experimental and multivariate statistical approach we have examined the mutagenicity and potential consequences of adduct formation by reactive intermediates in target uterine cells. pSP189 plasmid containing the supF gene was incubated with α-acetoxytamoxifen or 4-hydroxytamoxifen quinone methide (4-OHtamQM) to generate dG-N2-tamoxifen and dG-N2-4-hydroxytamoxifen, respectively. Plasmids were replicated in Ishikawa cells then screened in Escherichia coli. Treatment with both α-acetoxytamoxifen and 4-OHtamQM caused a dose-related increase in adduct levels, resulting in a damage-dependent increase in mutation frequency for α-acetoxytamoxifen; 4-OHtamQM had no apparent effect. Only α-acetoxytamoxifen generated statistically different supF mutation spectra relative to the spontaneous pattern, with most mutations being GC→TA transversions. Application of the LwPy53 algorithm to the α-acetoxytamoxifen spectrum predicted strong GC→TA hotspots at codons 244 and 273. These signature alterations do not correlate with current reports of the mutations observed in endometrial carcinomas from treated women, suggesting that dG-N2-tam adduct formation in the p53 gene is not a prerequisite for endometrial cancer initiation in women

K-ras mutation in the endometrium of tamoxifen-treated breast cancer patients, with a comparison of tamoxifen and toremifene

The putative presence of a mutation in codon 12 of the K-ras gene was investigated in the endometrium of tamoxifen (TAM) and toremifene (TOR)-treated breast cancer patients. DNA was extracted from fresh cytologic samples of the endometrium in 86 TAM and 21 TOR-treated breast cancer patients. Mutations were detected by enriched PCR and an enzyme-linked mini-sequence assay (ELMA). K-ras mutation was found in 35 TAM-treated endometrial samples, and in only one TOR-treated endometrium (P<0.003). In 24 premenopausal patients, K-ras mutation was found in seven (43.8%) of 16 patients with less than 47 months of TAM treatment, while none was found in eight patients with more than 48 months of TAM treatment (P<0.03). In 62 postmenopausal-amenorrheic patients, K-ras mutation was found in three (15.8%) of 19 patients with less than 23 months of TAM treatment, while it was found in 16 (61.5%) of 26 patients with 24–47 months of TAM treatment and nine (52.9%) of 17 patients with more than 48 months of TAM treatment (P=0.002). The presence of K-ras mutation is significantly influenced by the duration of TAM treatment and menstrual status of the patients. TOR may have a lower potential genotoxicity than TAM

On the stability of a class of shoreline planform models

AbstractThe evolution of beaches in response to the incident wave conditions has long attracted the attention of researchers and engineers. A popular mathematical model describing the change in the position of a single height contour on the coastline assumes that the beach profile is stable and the plan shape evolves due to wave-driven long-shore transport. Extensions of this model include more contours and allow for beach profile alteration through cross-shore transport of sediment. Despite this advantage, models with multiple contours remain relatively underused. In this paper we examine the stability of this class of model for the cases of one to three contours. Unstable modes may exist when there is more than one contour. These include short waves whose growth rate is strongly dependent upon wavenumber. For the case of three contours an additional long wave instability is possible. A necessary, but not sufficient, condition for instability is found. It requires a reversal of transport direction amongst the contours. The existence of these instabilities provides a possible explanation for the difficulties found in implementing computational multi-line models, particularly where structures alter the natural longshore transport rates so they satisfy, locally, the condition for instability

Relationship between C-telopeptide pyridinoline cross-links (ICTP) and putative periodontal pathogens in periodontitis

Crevicular fluid pyridinoline cross-linked carboxyterminal telopeptide of type 1 collagen (ICTP) is predictive for future alveolar bone loss in experimental periodontitis in dogs. The present study sought to relate ICTP to a panel of subgingival species in subjects exhibiting various clinical presentations such as health ( n = 7), gingivitis ( n = 8) and periodontitis (n=21), 28 subgingival plaque and GCF samples were taken from mesiobuccal sites m each of 36 subjects. The presence and levels of 40 subgtngivai taxa were determined in plaque samples using whole genomic DNA probes and checkerboard DNA-DNA hybridization. GCF ICTP levels were quantified using radioimmunoassay (RIA). Clinical assessments made at the same sites included: BOP, gingival redness, plaque, pocket depth, and attachment level. Differences among ICTP levels in the 3 subject groups were sought using the Kruskal-Wallis test. Relationships between ICTP levels and clinical parameters as well as subgingival species were determined by regression analysis. The results demonstrated significant differences among disease categories for GCF ICTP levels for healthy (1.1+0.6 pg/site (mean±SEM)) gingivitis (14.8±6.6 pg/site) and penodontitts subjects (30.3 + 5.7 pg/site) ( p = 0.0017). ICTP levels related modestly to several clinical parameters. Regression analysis indicated that ICTP levels correlated strongly with mean subject levels of several periodontal pathogens including B. forsythus, P. gingivitis, P. intermedia, P. nigrescens and T. dentcola ( p < 0.01). The data indicate that there is a positive relationship between the putative bone resorptive marker ICTP and periodontal pathogens.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74809/1/j.1600-051X.1998.tb02383.x.pd

Mutational Specificity of γ-Radiation-Induced Guanine−Thymine and Thymine−Guanine Intrastrand Cross-Links in Mammalian Cells and Translesion Synthesis Past the Guanine−Thymine Lesion by Human DNA Polymerase η†

ABSTRACT: Comparative mutagenesis of γ- or X-ray-induced tandem DNA lesions G[8,5-Me]T and T[5-Me,8]G intrastrand cross-links was investigated in simian (COS-7) and human embryonic (293T) kidney cells. For G[8,5-Me]T in 293T cells, 5.8 % of progeny contained targeted base substitutions, whereas 10.0 % showed semitargeted single-base substitutions. Of the targeted mutations, the G f T mutation occurred with the highest frequency. The semitargeted mutations were detected up to two bases 5 ′ and three bases 3 ′ to the cross-link. The most prevalent semitargeted mutation was a C f T transition immediately 5 ′ to the G[8,5-Me]T cross-link. Frameshifts (4.6%) (mostly small deletions) and multiple-base substitutions (2.7%) also were detected. For the T[5-Me,8]G cross-link, a similar pattern of mutations was noted, but the mutational frequency was significantly higher than that of G[8,5-Me]T. Both targeted and semitargeted mutations occurred with a frequency of ∼16%, and both included a dominant G f T transversion. As in 293T cells, more than twice as many targeted mutations in COS cells occurred in T[5-Me,8]G (11.4%) as in G[8,5-Me]T (4.7%). Also, the level of semitargeted single-base substitutions 5 ′ to the lesion was increased and 3 ′ to the lesion decreased in T[5-Me,8]G relative to G[8,5-Me]T in COS cells. It appeared that the majority of the base substitutions at or near the cross-links resulted from incorporation of dAMP opposite the template base, in agreement with the so-called “A-rule”. To determin

Techniques of disinformation: constructing and communicating "soft facts" after terrorism

Informed by social media data collected following four terror attacks in the UK in 2017, this article delineates a series of “techniques of disinformation” used by different actors to try and influence how the events were publicly defined and understood. By studying the causes and consequences of misleading information following terror attacks, the article contributes empirically to the neglected topic of social reactions to terrorism. It also advances scholarship on the workings of disinforming communications, by focusing on a domain other than political elections, which has been the empirical focus for most studies of disinformation to date. Theoretically, the analysis is framed by drawing an analogy with Gresham Sykes and David Matza's (1957) account of the role of “techniques of neutralization” originally published in the American Sociological Review. The connection being that where they studied deviant behaviour, a similar analytic lens can usefully be applied to disinformation cast as “deviant” information

Thinking about politics

There are distinctive modes of thinking about politics, three of which are discussed here. A mode consists of a characteristic domain of relevance, filing system, and grammar of beliefs. A person relying on Mode A treats politics as an extension of interpersonal experience. A person relying on Mode B organizes political thinking around a set of salient group identifications. A person relying on Mode C views public objects in terms of their consequences for collective goods. The three modes are illustrated by applying them to concrete issues in a hypothetical manner: Vietnam, bussing, and attitudes toward presidential candidates. The concept of surrogate attitudes is developed and various implications of the theoretical argument are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45481/1/11109_2004_Article_BF00988519.pd