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Cracowski JM, Sharma B, Brown DK, Christensen K, Lund BR, Smith DW. Perfluorocyclopentenyl (PFCP) Aryl Ether Polymers via Polycondensation of Octafluorocyclopentene with Bisphenols. Macromolecules 2011. [DOI: 10.1021/ma2024599] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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James MH, Charnley JL, Flynn JR, Smith DW, Dayas CV. Propensity to 'relapse' following exposure to cocaine cues is associated with the recruitment of specific thalamic and epithalamic nuclei. Neuroscience 2011; 199:235-42. [PMID: 21985936 DOI: 10.1016/j.neuroscience.2011.09.047] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 09/21/2011] [Accepted: 09/21/2011] [Indexed: 12/22/2022]
Abstract
The thalamus is considered an important interface between the ventral striatopallidum and the dorsal striatum, and may therefore contribute to compulsive drug-seeking behaviour. Recent evidence suggests that the paraventricular thalamus (PVT), a dorsal midline thalamic nucleus, and the mediodorsal thalamus (MD) are involved in drug self-administration and respond to drug-associated cues. At present, however, the role of these thalamic regions in mediating cue-induced reinstatement of cocaine-seeking is unclear. Similarly, the habenula complex, part of the epithalamus, has been implicated in nicotine self-administration and cue-induced reinstatement of heroin seeking, but the role of this region in cocaine reinstatement behaviour has received little attention. Rats (n=20) were trained to self-administer cocaine in the presence of discriminative stimuli associated with drug availability (S⁺) or drug non-availability (S⁻). Once a stable level of responding was reached, lever pressing was extinguished. Animals were then tested for reinstatement and sacrificed immediately following the presentation of either the S⁻ or S⁺ discriminative stimuli, and Fos-protein expression was assessed in thalamic and epithalamic regions. Interestingly, significant variation was observed in reinstatement behaviour, allowing a comparison between high-reinstating (HR), low-reinstating (LR) and control animals. Compared with LR animals, HR animals exhibited increased Fos-protein expression in the PVT, intermediodorsal thalamus and the medial and lateral divisions of the habenula. Our data provide evidence that activation of thalamic and epithalamic nuclei is associated with propensity to reinstate to cocaine-seeking elicited by drug-related cues. We also build upon existing data highlighting the importance of the PVT in reinstatement behaviour.
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Olvera N, Smith DW, Lee C, Liu J, Lee J, Kim JH, Kellam SF. Comparing high and low acculturated mothers and physical activity in Hispanic children. J Phys Act Health 2011; 8 Suppl 2:S206-S213. [PMID: 21918234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
BACKGROUND Parents represent a key ecological component in influencing their child's physical activity. The aim of this exploratory study was to assess the relationship between maternal acculturation and physical activity in Hispanic children. METHODS 102 Hispanic mothers (mean age 36.2 yrs; +SD 7.3 yrs) and their children (mean age 10.0 yrs, +SD 0.8 yrs) participated. Most of the mothers (74%) were foreign-born, with 62% classified as low acculturated and 38% high acculturated. Demographic, acculturation, and anthropometric measures were completed by mothers and children. Physical activity was measured using accelerometers. Relationships between maternal acculturation and demographic variables and children's physical activity were examined using chi-square, Analysis of Variance, and simple regression. RESULTS Children had higher physical activity levels than their mothers (t(49) = -7.87, P < .0001). Significant correlations between maternal and child's physical activity levels were observed in moderate (r2 = 0.13, P = .001), vigorous (r2 = 0.08, P = .05), and moderate-to-vigorous physical activity (r2 = 0.17, P = .002). Low acculturated mothers were more likely to have active children compared with high acculturated mothers. Maternal BMI and other demographic characteristics were not significantly associated with child's physical activity. CONCLUSIONS Findings from this study revealed an association among maternal acculturation, role modeling, and child's physical activity.
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Singh A, Naskar AK, Barden J, Drews MJ, Smith DW. Terpolymers from lactide and bisphenol a derivatives: Scale-up, properties, and blends. J Appl Polym Sci 2011. [DOI: 10.1002/app.33789] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Buenzli PR, Pivonka P, Smith DW. Spatio-temporal structure of cell distribution in cortical bone multicellular units: a mathematical model. Bone 2011; 48:918-26. [PMID: 21172465 DOI: 10.1016/j.bone.2010.12.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 12/06/2010] [Accepted: 12/12/2010] [Indexed: 10/18/2022]
Abstract
Bone remodelling maintains the functionality of skeletal tissue by locally coordinating bone-resorbing cells (osteoclasts) and bone-forming cells (osteoblasts) in the form of Bone Multicellular Units (BMUs). Understanding the emergence of such structured units out of the complex network of biochemical interactions between bone cells is essential to extend our fundamental knowledge of normal bone physiology and its disorders. To this end, we propose a spatio-temporal continuum model that integrates some of the most important interaction pathways currently known to exist between cells of the osteoblastic and osteoclastic lineage. This mathematical model allows us to test the significance and completeness of these pathways based on their ability to reproduce the spatio-temporal dynamics of individual BMUs. We show that under suitable conditions, the experimentally observed structured cell distribution of cortical BMUs is retrieved. The proposed model admits travelling-wave-like solutions for the cell densities with tightly organised profiles, corresponding to the progression of a single remodelling BMU. The shapes of these spatial profiles within the travelling structure can be linked to the intrinsic parameters of the model such as differentiation and apoptosis rates for bone cells. In addition to the cell distribution, the spatial distribution of regulatory factors can also be calculated. This provides new insights on how different regulatory factors exert their action on bone cells leading to cellular spatial and temporal segregation, and functional coordination.
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Perahia D, Traiphol R, Smith DW. Semifluorinated Polymeric Liquid Crystals as A Mechanistic Tool to Study The Effects of Interfacial Energies on The Orientation of Liquid Crystals. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-709-cc8.3.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTObtaining spontaneous orientation and fast collective response of ultra thin liquid crystalline (LC) layers to external stimuli without memory effects, is one of the major challenges in achieving the next generation of LC devices. The relationship between interfacial energies, structure and dynamics of support layers and their effects on surface orientation of liquid crystals has been investigated. A model polymeric system, containing a mesognic group, α- methylstilbene as anchoring group, bridged by an energy controlling moiety, fluorocyclobutyl, has been used to obtain substrates with controlled surface energy and structure. Neutron reflectivity was used to study the surface structure of the polymer. The orientation of a well characterized liquid crystal, 8CB that exhibits both nematic and Smectic phases, was studied by optical microscopy and small angle X-ray scattering. Correlation between the surface structure of the polymeric layer and the orientation of the Smectic phase indicated direct correlation between the surface orientation and the concentration of fluorine at the interface.
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Carcione D, Giele CM, Goggin LS, Kwan KSH, Smith DW, Dowse GK, Mak DB, Effler P. Secondary attack rate of pandemic influenza A(H1N1)2009 in Western Australian households, 29 May–7 August 2009. Euro Surveill 2011. [DOI: 10.2807/ese.16.03.19765-en] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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Carcione D, Giele CM, Goggin LS, Kwan KS, Smith DW, Dowse GK, Mak DB, Effler P. Secondary attack rate of pandemic influenza A(H1N1) 2009 in Western Australian households, 29 May-7 August 2009. Euro Surveill 2011; 16:19765. [PMID: 21262182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
Understanding household transmission of the pandemic influenza A(H1N1)2009 virus, including risk factors for transmission, is important for refining public health strategies to reduce the burden of the disease. During the influenza season of 2009 we investigated transmission of the emerging virus in 595 households in which the index case was the first symptomatic case of influenza A(H1N1)2009. Secondary cases were defined as household contacts with influenza-like illness (ILI) or laboratory-confirmed influenza A(H1N1)2009, occurring at least one day after but within seven days following symptom onset in the index case. ILI developed in 231 of the 1,589 household contacts, a secondary attack rate of 14.5% (95% confidence interval (CI): 12.9–16.4). At least one secondary case occurred in 166 of the 595 households (a household transmission rate of 27.9%; 95% CI: 24.5–31.6).Of these, 127 (76.5%) households reported one secondary case and 39 (23.5%) households reported two or more secondary cases. Secondary attack rates were highest in children younger than five years (p=0.001), and young children were also more efficient transmitters (p=0.01). Individual risk was not associated with household size. Prophylactic antiviral therapy was associated with reduced transmission (p=0.03). The secondary attack rate of ILI in households with a confirmed pandemic influenza A(H1N1)2009 index case was comparable to that described previously for seasonal influenza.
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Singh A, Naskar AK, Haynes D, Drews MJ, Smith DW. Synthesis, characterization and surface properties of poly(lactic acid)-perfluoropolyether block copolymers. POLYM INT 2010. [DOI: 10.1002/pi.2982] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Blyth CC, Kelso A, McPhie KA, Ratnamohan VM, Catton M, Druce JD, Smith DW, Williams SH, Huang QS, Lopez L, Schoub BD, Venter M, Dwyer DE. The impact of the pandemic influenza A(H1N1) 2009 virus on seasonal influenza A viruses in the southern hemisphere, 2009. Euro Surveill 2010. [DOI: 10.2807/ese.15.31.19631-en] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Data collected over winter 2009 by five World Health Organisation National Influenza Centres in the southern hemisphere were used to examine the circulation of pandemic and seasonal influenza A strains during the first pandemic wave in the southern hemisphere. There is compelling evidence that the pandemic influenza A(H1N1) 2009 virus significantly displaced seasonal influenza A(H1N1) and, to a lesser extent, A(H3N2) viruses circulating in the southern hemisphere. Complete replacement of seasonal influenza A strains, however, was not observed during the first pandemic wave.
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Blyth CC, Kelso A, McPhie KA, Ratnamohan VM, Catton M, Druce JD, Smith DW, Williams SH, Huang QS, Lopez L, Schoub BD, Venter M, Dwyer DE. The impact of the pandemic influenza A(H1N1) 2009 virus on seasonal influenza A viruses in the southern hemisphere, 2009. Euro Surveill 2010; 15:19631. [PMID: 20738990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
Data collected over winter 2009 by five World Health Organisation National Influenza Centres in the southern hemisphere were used to examine the circulation of pandemic and seasonal influenza A strains during the first pandemic wave in the southern hemisphere.There is compelling evidence that the pandemic influenza A(H1N1) 2009 virus significantly displaced seasonal influenza A(H1N1) and, to a lesser extent, A(H3N2) viruses circulating in the southern hemisphere. Complete replacement of seasonal influenza A strains, however, was not observed during the first pandemic wave.
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Carcione D, Giele C, Goggin LS, Kwan KS, Smith DW, Dowse GK, Mak DB, Effler P. Association between 2009 seasonal influenza vaccine and influenza-like illness during the 2009 pandemic: preliminary results of a large household transmission study in Western Australia. Euro Surveill 2010. [DOI: 10.2807/ese.15.28.19616-en] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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Carcione D, Giele C, Goggin LS, Kwan KS, Smith DW, Dowse GK, Mak DB, Effler P. Association between 2009 seasonal influenza vaccine and influenza-like illness during the 2009 pandemic: preliminary results of a large household transmission study in Western Australia. Euro Surveill 2010; 15:19616. [PMID: 20650055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
We conducted a prospective household transmission study to examine whether receipt of 2009 trivalent influenza vaccine (TIV) was associated with increased risk of influenza-like illness (ILI) among contacts of confirmed pandemic influenza A(H1N1) 2009 patients. In the week following onset of pandemic illness in a household member, 46 (15%) of 304 TIV-vaccinated contacts, and 174 (15%) of 1,162 unvaccinated contacts developed ILI (p=0.95). Receipt of 2009 TIV had no effect on one's risk of pandemic illness.
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Dicker HJ, Smith DW. Enumeration and relative importance of acetylene-reducing (nitrogen-fixing) bacteria in a delaware salt marsh. Appl Environ Microbiol 2010; 39:1019-25. [PMID: 16345564 PMCID: PMC291468 DOI: 10.1128/aem.39.5.1019-1025.1980] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three groups of N(2)-fixing bacteria were enumerated from the top 1 cm of the surface in four vegetational areas in a Delaware salt marsh. The results over the 9-month sampling period showed that there were no discernible seasonal patterns for any of the groups enumerated (Azotobacter sp., Clostridium sp., and Desulfovibrio sp.). Azotobacter sp. was present in numbers of 10 per g of dry mud, whereas the two anaerobic fixers were present in much lower numbers (10 to 10 per g of dry mud). There were no differences in the numbers of each group among the different vegetational areas, indicating that there was a heterogeneous population of N(2) fixers present. Additional studies indicate that the activity of sulfate reducers (Desulfovibrio sp.) may account for as much as 50% of the total observed acetylene reduction activity. Oxygen was found to exert little effect on the observed acetylene reduction activity, indicating that stable aerobic and anaerobic microenvironments exist in the surface layer of marsh sediments.
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Abstract
Rhodanese (thiosulfate:cyanide sulfurtransferase; EC 2.8.1.1) catalyzes the conversion of thiosulfate and cyanide to thiocyanate and sulfite. Conventional rhodanese assays colorimetrically measure the formation of one or the other of the products. These assays suffer from the fact that there is significant nonbiological formation of these products in addition to the enzymatically catalyzed reaction. In the present report, we describe a modified procedure for assaying rhodanese in which a separate boiled control was prepared for each assay trial. The boiled control corrected for the nonbiological contributions to product formation.
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Li X, Nour MH, Smith DW, Prepas EE. Neural networks modelling of nitrogen export: model development and application to unmonitored boreal forest watersheds. ENVIRONMENTAL TECHNOLOGY 2010; 31:495-510. [PMID: 20480825 DOI: 10.1080/09593330903527880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In remotely located boreal forest watersheds, monitoring nitrogen (N) export in stream discharge often is not feasible because of high costs and site inaccessibility. Therefore, modelling tools that can predict N export in unmonitored watersheds are urgently needed to support management decisions for these watersheds. The hydrological and biogeochemical processes that regulate N export in streams draining watersheds are complex and not fully understood, which makes artificial neural network (ANN) modelling suitable for such an application. This study developed ANN models to predict N export from watersheds relying only on easily accessible climate data and remote sensing (RS) data from the public domain. The models were able to predict the daily N export (g/km2/d) in five watersheds ranging in size from 5-130 km2 with reasonable accuracy. Similarity indices were developed between any two studied watersheds to quantify watershed similarity and guide the transferability of models from monitored watersheds to unmonitored ones. To demonstrate the applicability of the ANN models to unmonitored watersheds, the calibrated ANN models were used to predict N export in different watersheds (unmonitored watersheds in this perspective) without further calibration. The similarity index based upon a rainfall index, a peatland index and a RS normalized difference water index showed the best correlation with the transferability of the models. This study represents an important first step towards transferring ANN models developed for one watershed to unmonitored watersheds using similarity indices that rely on freely available climate and RS data.
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Olvera N, Scherer R, McLeod J, Graham M, Knox B, Hall K, Butte NF, Bush JA, Smith DW, Bloom J. BOUNCE: an exploratory healthy lifestyle summer intervention for girls. Am J Health Behav 2010; 34:144-55. [PMID: 19814594 DOI: 10.5993/ajhb.34.2.2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVES To assess the efficacy of the BOUNCE parent-daughter intervention in promoting selected physical fitness measures and activity. METHODS Thirty-seven Latino and African American parent-daughter pairs participated. The intervention entailed physical activities, nutrition classes, and self-esteem activities. Child's height, weight, waist circumference, body fat %, blood pressure, physical fitness, and activity were assessed pre- and postintervention. RESULTS A repeated-measures ANOVA yielded significant results [F(4,26) = 793.003, P < 0.001]. Post hoc analyses demonstrated significant (P < 0.05) changes in BMI, waist circumference, physical fitness, and activity. CONCLUSIONS The BOUNCE intervention was effective in promoting fitness and activity in minority girls.
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Iacono ST, Budy SM, Smith DW, Mabry JM. Preparation of composite fluoropolymers with enhanced dewetting using fluorinated silsesquioxanes as drop-in modifiers. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b924337b] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Iacono ST, Budy SM, Moody JD, Smith RC, Smith DW. Modular Approach to Chromophore Encapsulation in Fluorinated Arylene Vinylene Ether Polymers Possessing Tunable Photoluminescence. Macromolecules 2008. [DOI: 10.1021/ma801440t] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Jiang J, Callender CL, Jacob S, Noad JP, Chen S, Ballato J, Smith DW. Long-range surface plasmon polariton waveguides embedded in fluorinated polymer. APPLIED OPTICS 2008; 47:3892-3900. [PMID: 18641759 DOI: 10.1364/ao.47.003892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Low-attenuation waveguides based on the propagation of long-range surface plasmon polaritons (LRSPPs) along thin Au stripes embedded in low absorption perfluorocyclobutane (PFCB) polymer are presented. A new low in propagation loss of <2.0 dB/cm was achieved for a 4 microm wide waveguide by optimizing the cladding material and fabrication process. The coupling efficiency between the LRSPP waveguide and the optical fiber is studied theoretically and experimentally for different widths of Au stripes and various cladding thicknesses. Lower coupling loss is found when the cladding thickness is close to the mode diameter of the butt-coupled fiber. Based on the 2D distribution of SPP modes calculated by a finite-difference mode solver, a symmetric structure of multilayer claddings with different refractive indices is proposed to optimize device insertion loss.
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Neilson AR, Budy SM, Ballato JM, Smith DW. Synthesis and characterization of highly fluorescent phenylene vinylene containing perfluorocyclobutyl (PFCB) aromatic ether polymers. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.05.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gao W, Smith DW, Habib M. Petroleum refinery secondary effluent polishing using freezing processes--toxicity and organic contaminant removal. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2008; 80:517-523. [PMID: 18686927 DOI: 10.2175/106143008x266814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A petroleum refinery secondary effluent was treated using two freezing techniques--spray freezing and unidirectional downward freezing (UDF). The freezing processes were effective to remove toxicity and total organic carbon (TOC)- and chemical oxygen demand (COD)-causing materials in the effluent. Agitation of the liquid during UDF significantly improved the impurity separation efficiency; 85 to 96% removal of TOC and COD was achieved without any pretreatment and freezing only 70% of the feed water. The treatment efficiency of the spray freezing was at the same level as that of UDF without mixing. The spray ice with longer storage time released more contaminants with early meltwater. The initial contaminant concentration of the feed water and the freezing temperatures (-10 degrees C and -25 degrees C) had no significant influence on the treatment efficiency. A small fluctuation in effluent TOC concentration caused a dramatic change in effluent toxicity (Microtox). The effective concentration (EC20) (Microtox) was effective in detecting effluent toxicity.
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Iacono ST, Ewald D, Sankhe A, Rettenbacher A, Smith DW. Sulfonated Fluorovinylene Aromatic Ether Polymers for Proton Exchange Membranes2. HIGH PERFORM POLYM 2008. [DOI: 10.1177/0954008307081200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A new semi-fluorinated perfluorocyclobutyl (PFCB) aryl ether containing polymer was prepared in high yield via the condensation of a commercial 4,4'-((1,2,3,3,4,4-hexafluorocyclobutane-1,2-diyl)bis(oxy))bisphenol (bisphenol T) and bis(trifluorovinyloxyether)biphenyl producing transparent, flexible films. The polymer system was structurally characterized using 1H and 19F NMR and exhibited a high degree of thermal stability as determined by thermogravimetric analysis capacity. The sulfonated analogue showed the highest degree of sulfonation at 27% from ion-exchange chromatography, producing a conductivity of 0.011 S cm-1 at 100% relative humidity.
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Neilson RH, Ji J, Narayan-Sarathy S, Smith DW, Babb DA. New Phosphorus-Fluorocarbon Hybrid Polymer Systems. PHOSPHORUS SULFUR 2008. [DOI: 10.1080/10426509908546222] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Smith DW, Morgan AM, Pooler AM, Thwaites DI. Comparison between margin-growing algorithms in radiotherapy software environments. Br J Radiol 2008; 81:406-12. [PMID: 18283072 DOI: 10.1259/bjr/51255006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Margin-growing algorithms are commonly used tools that are available within virtual simulation and treatment planning software. We report on the accuracy of the margin-growing algorithms available in six commercially available radiotherapy software environments. A phantom containing two differently sized spheres and two rods (one level and one inclined) was constructed and scanned by CT with 1.25 mm, 2.5 mm, 3.75 mm and 5 mm slice thicknesses. The objects were outlined on a GE Advantage Simulator, and the outlined volumes recorded. Images and structures were transferred to MasterPlan, Xio, Pinnacle, Eclipse and Prosoma, where imported volumes were recorded. The contours on each system were grown isotropically by 10 mm, 20 mm and 30 mm, and volumes for each grown contour were recorded. Transfer of structure sets created in GE Advantage Simulator to the other software environments showed that the reported volumes of the four structures differ on each system. Results showed no correlation between volume accuracy and slice thickness. In general, margin growth of up to 30 mm for the rods and spheres is shown to be consistent between systems to within 1.33 mm for all slice thicknesses. Slice thickness did not appear to influence the accuracy of margin growth. Although this work highlights apparent differences in the reported volumes grown from the same original structure sets, the significance of this aspect of the planning process needs to weighed against reported intra- and inter-clinician variability in contour definition. It is not unreasonable, however, to expect that software packages should at least be consistent in volume information provided to the user.
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