bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxicity screening, assessment, and reduction in an industrial wastewater treatment plant
Authors: Ince Nilsun H. , Erdoğdu Gülnaz
Published: September 2006

The toxicity reduction capacity of a central wastewater treatment plant (CWTP) receiving 21 000 metric ton/d of industrial wastewater was thoroughly investigated using a whole‐effluent approach with a Microtox™ Toxicity Analyzer System. It was found that the highly toxic wastewater introduced into the CWTP was almost completely detoxified during secondary treatment with a recycled activated‐sludge system. The removal mechanism was shown to be a combination of adsorption, volatilization, and biodegradation, the first two being more clear than the other. Fractionation of toxic streams within the treatment plant provided valuable information about the general characteristics of the toxicity‐causing agents in the wastewater, namely that they were primarily composed of filterable and dissolved solids, volatile organics, and nitrogenous compounds. A toxicity reduction evaluation survey within the plant revealed that the observed Microtox™ toxicity could be readily removed by treatment with powdered activated carbon (PAC) and mechanical aeration at properly selected operating conditions. The correlation between toxicity removal and the applied PAC dose was found to be exponential and asymptotic to the ultimate effective toxicant concentration of the effluent. Reductions in chemical oxygen demand and dissolved organic carbon during PAC treatment were also related to the applied PAC dose and the initial concentrations of the parameter. Removal of volatile components of toxicity by aeration was correlated with detention time by a power function.
The effect of environmental factors on bacterial populations and community dynamics in high rate oxidation ponds
Authors: Bahlaoui Moulay A. , Baleux Bernard
Published: September 2006

The effect of environmental factors on different bacterial populations and cultivable heterotrophic bacteria community dynamics in an experimental high‐rate oxidation pond (HROP) was studied. After 24 months of weekly and bimonthly sampling, the relationships between bacteriological and environmental variables at the outflow of the HROP were modeled. Path analysis applied to the in‐situ data provided evidence of very different behavioral models according to bacteriological variables and the scale of sampling. The fecal coliform and fecal streptococci distributions showed seasonal cycles, with low summer and high winter abundances. Solar radiation, water temperature, pH and chlorophyll a concentration were the main environmental variables affecting the temporal dynamics of these bacterial populations, the effects of which were different on each bacterial group. No cyclic behavior was found for Aeromonas spp. whose abundances were irregular and closely related to water temperature and chemical oxygen demand. The temporal dynamic of the cultivable heterotrophic bacteria community was found to be independent of the majority of the model's predictive variables, indicating its maturation as an endogenous community in the high‐rate pond ecosystem. These results suggest that fecal‐indicator bacteria are controlled by different processes occurring in the high‐rate pond than are the Aeromonas spp. and aerobic heterotrophic bacteria.
The use of mathematical modeling and pilot plant testing to develop a new biological phosphorus and nitrogen removal process
Authors: Nolasco Daniel A. , Daigger Glen T. , Stafford Dalton R. , Kaupp Douglas M. , Stephenson Joe P.
Published: September 2006

A mechanistic mathematical model for carbon oxidation, nitrogen removal, and enhanced biological phosphorus removal was used to develop the Step Bio‐P process, a new biological phosphorus and nitrogen removal process with a step‐feed configuration. A 9 000‐L pilot plant with diurnally varying influent process loading rates was operated to verify the model results and to optimize the Step Bio‐P process for application at the Lethbridge, Alberta, Canada, wastewater treatment plant. The pilot plant was operated for 10 months. An automatic on‐line data acquisition system with multiple sampling and metering points for dissolved oxygen, mixed liquor suspended solids, ammonia–nitrogen, nitrate–nitrogen, ortho‐phosphate, and flow rates was used. A sampling program to obtain off‐line data was carried out to verify the information from the on‐line system and monitor additional parameters. The on‐line and off‐line data were used to recalibrate the model, which was used as an experimental design and process optimization tool. The pilot plant results matched and verified the initial mathematical model results. Total phosphorus concentrations were reduced from 14 mg P/L in the biological process influent to less than 1 mg P/L in the secondary effluent. Complete nitrification and 85% nitrogen removal were consistently achieved, and sludge with excellent settling characteristics (sludge volume index values of approximately 80 mL/g) was produced. The step‐feed configuration allows an increased bioreactor suspended solids inventory to be maintained while, at the same time, reducing the solids loading rate to the secondary clarifiers. The result is maximum use of existing facilities. The Step Bio‐P process is particularly suited for retrofitting conventional activated‐sludge plants with limited secondary clarifier capacity to achieve biological nutrient removal (BNR). The combined mathematical modeling and pilot testing program demonstrated that the primary factors affecting the performance of the Step Bio‐P process are flow‐split percentages, mean cell residence time, dissolved oxygen set points, and short chain volatile fatty acid addition. Process performance is relatively insensitive to anoxic recycle and return activated‐sludge flow rates. The growth of excessive quantities of glycogen accumulating organisms occurred when an industrial wastewater with high sugar concentrations was treated. Their growth adversely affected the biological phosphorus removal efficiency of the process. Strategies for controlling growth of these organisms were evaluated and tested.
Evaluation of IAWQ Activated Sludge Model No. 2 using steady‐state data from four full‐scale wastewater treatment plants
Authors: Çinar Özer , Daigger Glen T. , Graef Stephen P.
Published: September 2006

Several new tools, including the Activated Sludge Model No.2 (ASM No. 2) developed by the International Association on Water Quality, are becoming available to analyze the nutrient removal capability of existing wastewater treatment plants (WWTPs). The ASM No. 2 is a potentially inexpensive and effective tool, but its use needs to be evaluated. To solve the differential equations in the model, the computer program Activated Sludge Simulation Program (ASIM 3.0) was used. The model was calibrated using data from the Mauldin Road WWTP, which is a nutrient removal plant. Only 6 of 71 stoichiometric and kinetic parameter values were changed from suggested default values. The stoichiometric and kinetic parameters determined for the Mauldin Road WWTP were then used to develop models for the Lower Reedy, Gilder Creek, and Durbin Creek WWTPs. The calibrated model was subsequently confirmed using separate data sets for each WWTP. The model was successfully calibrated and confirmed at the Lower Reedy WWTP. This plant uses high‐speed mechanical surface aerators, and it achieves significant phosphorus removal. It was modeled by specifically considering the flow pattern likely to be created by these aerators. Several options to improve the phosphorus removal capability of the Lower Reedy WWTP were evaluated. The simulation results suggested that phosphorus removal performance could be improved by repositioning the mechanical surface aerators to produce a defined anaerobic zone and by providing dissolved oxygen control. The performance of the Durbin Creek and Gilder Creek WWTPs, which use oxidation ditch processes, could not be fully simulated using the model. Potential reasons for this failure are discussed.
Degradation of organic compounds in a municipal landfill leachate treated in a suspended‐carrier biofilm process
Authors: Welander U. , Henrysson T.
Published: September 2006

Leachate from a Swedish municipal landfill was analyzed for organic compounds before and after biological treatment in a pilot plant. The treatment consisted of two stages: one aerobic (nitrification) and one anoxic (denitrification), both working as suspended‐carrier biofilm processes. The chemical oxygen demand reduction in the aerobic stage was 15 to 30% during the study. Ultrafiltration and gel filtration chromatography studies showed that mainly organic compounds with a low molecular weight were degraded during treatment; however, a fraction of these low‐molecular‐weight compounds was still left after treatment. Furthermore, reversed‐phase chromatography analyses indicated that a large part of the hydrophilic fractions of the organic compounds were unaffected by the treatment. Gas chromatography–mass spectrometry analyses showed that the leachate contained low concentrations of plasticizers and polycyclic aromatic hydrocarbons. Toxicity tests indicated that much, but not all, of the toxicity depended on the high ammonium ion concentration in the untreated leachate.
An estimate of activated‐sludge floc permeability: a novel hydrodynamic approach
Authors: Wu R.M. , Feng W.H. , Tsai I.H. , Lee D.J.
Published: September 2006

This work estimates the interior permeability of waste activated sludge flocs by observing the motion of individual flocs moving vertically toward an impermeable flat plate. Through a comparison of experimental data with theoretical predictions in the literature, floc permeabilities of original sludge and freeze–thaw‐conditioned sludges are found to be 0.7 × 10−7 to 5 × 10−7 m2 and 0.9 × 10−9 to 6 × 10−9 m2, respectively. Moreover, incorporating inertial effect delays the influence of the flat plate, thereby causing the creeping‐flow‐based correlation to fail.
A rotating membrane contactor: experimental studies
Authors: Johnson Drew W. , Semmens Michael J. , Gulliver John S.
Published: September 2006

In this study, unconfined hollow‐fiber membrane modules are designed to be attached to a rotating arm that pulls the fibers through water. This use of unconfined membranes is well suited to environmental applications where waters often contain high solids concentrations that can rapidly clog or foul tightly packed conventional tubular membrane module designs. Pressurized oxygen was supplied to the fibers, and the mass‐transfer rates and energy requirements of a rotating membrane contactor were measured over a practical range of design and operating conditions. Mass‐transfer performance of the unconfined membranes was correlated with the Reynolds number to the 0.52 power. Over the range of values tested, performance was independent of the length, number, and spacing of hollow‐fiber membranes; the vertical arm diameter; and the radial position of the vertical arm from the center shaft. The clean water mass‐transfer efficiency (kg O2/kW · h) of the contactor was found to be superior to commercially available pure‐oxygen dissolution systems and other membrane contactor designs.
Winter temperature gradients in circular clarifiers
Authors: Wells Scott A. , LaLiberte David M.
Published: September 2006

To understand the effect of temperature‐induced density currents on circular clarifiers, a field study was performed on three uncovered circular tanks in Oregon during periods of low flow and high surface cooling. Temperatures were measured as a function of radial position and tank depth. Meteorological parameters were also measured to compute the surface heat flux from the water surface. Water temperatures in the tank were often 20 to 30 °C warmer than the equilibrium temperature. These studies showed that density currents and unstable temperature gradients were common. Surface temperatures were often approximately 1 °C cooler than bottom temperatures. The momentum and suspended solids of the inflow caused a density current that moved along the clarifier bottom and then rose near the middle of the tank. In the winter, this density current rose as a result of the decrease of initial momentum of the inflow, the buoyancy of the inflow after suspended solids had settled, and the geometry of the tank. Also, vertical velocities induced by surface cooling were two orders of magnitude greater than the overflow rate, suggesting that particles could be kept in suspension by convective currents.
A simple method for determination of volatile acid concentration with corrections for ionic strength
Authors: Bisogni James J. , Witzmann Stephen W. , Stedinger Jery R.
Published: September 2006

A relatively simple but accurate method to determine volatile acid concentration in aqueous solutions is presented. This new method extends a less accurate procedure previously proposed to account for ionic strength and combines several volatile acid concentrations into a composite value. Both procedures use all available titration data, instead of the customary single titration endpoint. The simplified procedure is implemented using common spreadsheets as a tool for data analysis. Analysis of titration data for solutions of known concentration and anaerobic digester supernatant spiked with acetic acid verified the new procedure's wide applicability.
Uprating and rescuing small wastewater treatment facilities by adding tertiary treatment reed beds
Authors: Green M.B. , O'Connell P.J. , Griffin P.
Published: September 2006

A water utility developed use of gravel‐filled constructed reed beds operating in a subsurface flow mode to polish secondary effluent to meet demanding standards for 5‐day biochemical oxygen demand (BOD5) and total suspended solids. Results collected by the regulatory environmental agency (EA) for 43 sites completed before the end of 1993 are given. The average BOD5 concentration was 1.9 mg/L. The benefit of effluent polishing is further demonstrated by influent and effluent data from two sites that have operated since June 1990 and September 1991, respectively. Environmental agency effluent quality data are also given for 39 sites at which reed beds either treat stormwater and secondary effluent together or have been installed as remedial treatment for works struggling to meet secondary treatment standards. The average BOD5 concentration for these sites was 3.0 mg/L. Remedial, or treatment plant rescue, application is illustrated by four contrasting case studies where constructed reed beds brought facilities back into compliance.
Recalcitrant organic compounds (chemical oxygen demand sources) in biologically treated pulp and paper mill effluents: their fate and environmental impact in receiving waters
Authors: Archibald Fred , Roy‐Arcand Line , Méthot Myriam , Valeanu Loredana
Published: September 2006

Most North American pulp and paper mills now biologically treat (biotreat) their liquid effluent. However, treated water still contains effluent‐derived recalcitrant organic material (EROM), measured as chemical oxygen demand (COD), for which emission limits exist in Europe and are being considered in the U.S. Production of microbially resistant, dissolved natural organic material (NOM) typically found in Canadian stream and lake waters occurs slowly under gentle conditions, while mill EROM is generated from lignocellulosics by faster and harsher processes. Similarity of the environmental effects of NOM and pulp and paper mill EROM are examined. Changes occurring over 4 months in biologically treated effluent from two modern Canadian mills and lake NOM when sealed in gas‐ and light‐permeable bags and placed in a pristine Quebec lake are reported. Addition of microbial co‐metabolites significantly improved the dark mineralization of organochlorines surviving mill biological treatment. Mill EROM was light sensitive, nonacutely toxic in the Microtox assay, and similar to NOM in the surrounding lake in most bulk properties. There was no evidence to suggest that placing specific limits on mill EROM (COD) emissions would be environmentally beneficial.
Evaluation of sampling frequency for the water quality monitoring network of coastal Galicia (northwest Spain)
Authors: Antelo J.M. , Arce F. , Carballeira J.L.
Published: September 2006

To contribute to the efficiency of the water quality monitoring network of the hydrographical area of coastal Galicia (Northwest Spain), a sampling frequency that would ensure reliable verification of compliance with European Union standards, and a preliminary trend estimation of water quality are calculated. The criterion applied was that for each of four quality determinants (flow rate, chemical oxygen demand, conductivity, and percent dissolved oxygen), the sampling frequency should ensure a 95% confidence interval for the annual mean whose upper limit would lie below the corresponding legal threshold. During the study, all water tested complied with the more stringent standards for drinking water. The confidence interval and trend for flow rate were also calculated.
Ozonization of 2,4‐dinitrotoluene and 4‐nitroaniline as well as improved dissolved organic carbon removal by sequential ozonization–biodegradation
Authors: Saupe Adrian , Wiesmann Udo
Published: September 2006

The effects of varying pH on substrate removal, nitrate formation, and dissolved organic carbon (DOC) removal during the ozonization of aqueous solutions of 2,4‐dinitrotoluene (DNT) and 4‐nitroaniline (NA) were investigated in semibatch systems under partially mass‐transfer–limited conditions. If ozonization was performed outside the region of strong mass‐transfer limitation, a strong pH influence was observed for the treatment of DNT. At pH 2, the rate of DNT removal was small and DNT was poorly degraded. Both nitro groups were split off and immediately oxidized to nitrate at pH 2 and pH 7. An increase in the pH, to a minimum value of 7, during the oxidation of DNT and NA caused radical reactions and, thus, a higher degree of simultaneous DOC removal. Furthermore, nitrogen‐containing organic metabolites were produced from DNT because of these radical reactions when the ozonization was carried out at pH 11. Sequential semibatch ozonization (pH 7) and biodegradation resulted in complete removal of the nitroaromatics and a minimum overall DOC removal of 75% with minimum specific‐ozone doses of 4 g/g and 3 g/g for DNT and NA, respectively. Compared to this, no ozone savings were achieved with a continuous‐flow chemical–biological treatment system. This effect was caused by the unfavorable reaction conditions in the totally mixed ozonization reactor.
Enrichment and operation strategies for polychlorophenol degrading microbial cultures in an aerobic fluidized‐bed reactor
Authors: Melin Esa S. , Puhakka Jaakko A. , Ferguson John F.
Published: September 2006

A 2,3,4,6‐tetrachlorophenol‐ (TeCP‐) and pentachlorophenol‐ (PCP‐) degrading microbial culture was enriched from supernatant of municipal activated sludge using laboratory‐scale continuous‐flow fluidized‐bed reactors (FBRs). Effluent concentrations of less than 10 μg/L were obtained within 12 days for TeCP and within 24 days for PCP at influent concentrations of 22 and 3.1 mg/L of TeCP and PCP, respectively, and at a 5‐hour hydraulic retention time (HRT). Shorter HRTs at similar chlorophenol loading rates resulted in longer start‐up times. Biodegradation of PCP was always more sensitive to increases in loading rate or decreases in HRT than was TeCP degradation. With TeCP and PCP loading rates of 100 and 15 mg/L·d, respectively, effluent TeCP concentrations of less than 10 μg/L were achieved even at a 3.7‐minute HRT, while PCP removal efficiency started to decrease at HRTs of less than 38 minutes. During shock loading tests at a 14‐minute HRT, more than 99.9% TeCP degradation was obtained at a 2 200‐mg/L·d loading rate, while PCP degradation remained at 73% at a loading rate of 314 mg/L·d. In batch degradation tests in the FBR, TeCP degradation followed Michaelis–Menten kinetics at initial concentrations of less than 31 mg/L, with a minimum specific substrate rate (qmax) of 0.59 mg TeCP/mg volatile solids (VS)·d and Ks (half‐saturation constant) of 0.41 mg/L. Pentachlorophenol degradation was modeled using the modified Haldane equation with the following kinetic constants: qmax = 0.066 mg PCP/mg VS·d, Ks = 1.1 mg/L, Ki (inhibition constant) = 1.7 mg/L, and n (constant) = 3. The results showed that FBR rapidly enriches chlorophenol‐degrading cultures able to produce good‐quality effluents. After start‐up, FBRs can be operated over a wide range of loading rates for bioremediation of chlorophenol‐contaminated water.
Making a trickling filter/solids contact process work for cold weather nitrification and phosphorus removal
Authors: Parker Denny S. , Romano Lou S. , Horneck Harold S.
Published: September 2006

It is anticipated that the West Windsor Pollution Control Plant (WWPCP) (Windsor, Ontario, Canada) will be required to be upgraded from its current chemical primary treatment to full secondary treatment, with phosphorus removal maintained. A steering committee established effluent design objectives for effluent suspended solids and total 5‐day biochemical oxygen demand of 15 mg/L, total phosphorus of 0.5 mg/L, and ammonia‐nitrogen of 3 mg/L. Four processes were tested; among these, the trickling filter/solids contact (TF/SC) process had not been tested previously for consistent nitrification in colder climates where average monthly wastewater temperatures fall to 9 to 10°C. A novel TF/SC treatment scheme was identified that took advantage of the low biochemical oxygen demand of the WWPCP's chemical primary effluent and used higher density cross‐flow media than had previously been used in the TF/SC process to achieve nitrification. In initial testing, the TF/SC process nitrified successfully but failed to meet the other objectives. A detailed diagnosis showed that the best process configuration had not been tested and that the pilot design was flawed in several respects. The inclusion of a sludge reaeration tank, the substitution of a flocculator‐clarifier for a conventional scraper clarifier, and the elimination of head losses causing excessive floc breakup corrected the problem. In testing over a year‐long period, the TF/SC process consistently met the target objectives, moving it up from fourth place to a tie with the other first‐ranked process, the biological aerated filter (BAF). Capital costs were found to be lower than for the activated‐sludge process and the BAF processes.
Simulation of sludge pumping
Authors: List E. John , Hannoun Imad A. , Chiang Wen‐Li
Published: September 2006

The operation of many waste water treatment plants involves the pumping of sludge cake using positive‐displacement pumps. This paper discusses the development of a computational model, based on first principles, for simulating the pumping of sludge cake with a relatively low moisture content. It provides a design method that is developed from analysis. The partial differential equations in the model are solved by the method of characteristics. The method of analysis is applied to several sludge‐pumping conditions. The model results are compared to the field data. The comparison shows that the model is capable of predicting the transient pressures with in the pipeline.
Biodegradation kinetics of chlorophenols in immobilized‐cell reactors using a white‐rot fungus on wood chips
Authors: Yum Kyu‐Jin , Peirce J. Jeffrey
Published: September 2006

This research investigated the ability of wood‐chip reactors seeded with a white‐rot fungus (Phanerochaete chrysosporium) to degrade hazardous substances (4‐chlorophenol [4‐CP] and 2,4‐dichlorophenol [2,4‐DCP]). Batch‐reactor tests were conducted using 4‐CP as a model compound to evaluate the effect of carbon and nitrogen deficiencies on the ability of white‐rot fungus immobilized on wood chips to degrade 4‐CP. The white‐rot fungus degraded 4‐CP (71.1 to 83.0%) under all tested conditions including the non‐glucose and non‐nitrogen conditions. However, there are differences in the degradation percentage of 4‐CP using the different growing conditions. The degradation of 4‐CP occurs to the greatest extent in the non‐glucose/with‐nitrogen condition (15.38 ppm/h·g of specific biodegradation rate). Continuous‐flow packed‐bed reactor tests are conducted using 2,4‐DCP as a model compound to evaluate the inhibition effect of 2,4‐DCP on the biodegradation enzymes in wood‐chip reactor systems, and the inhibition effects seem to be present. The inhibition kinetics of 2,4‐DCP are successfully modeled with the mass‐balance equation of plug‐flow reactors and a substrate‐inhibition equation for the reaction rate, yielding an inhibition constant,Ki of 69.8 ppm and a maximum 2,4‐DCP concentration, [S]max, of 48.9 ppm at the highest reaction rate. The importance of these results is that the substrate‐inhibition model can be used to explain the inhibition effect of 2,4‐DCP on the biodegradation enzymes in this wood‐chip reactor system. This study points to the potential of continuous‐flow reactors using wood chips as a carbon source to degrade toxic chemicals with high‐degradation efficiency.
Effect of calcium oxide dose on thermal reactions, lime speciation, and physical properties of alkaline stabilized biosolids
Authors: Smith Karen A. , Goins Lori E. , Logan Terry J.
Published: September 2006

Quicklime (CaO) was added to a single sample of dewatered biosolids at rates of 5, 15, 20, 25, 30, 40, and 50% by weight (based on wet weight of the dewatered biosolids) in the laboratory. Temperature rise and water loss were monitored to determine caloric energy expended in heating and evaporation, and these values were compared to heat generation. The limed biosolids were analyzed by x‐ray diffraction and thermal gravimetric analysis to determine the lime species present, and the pH rise when added to selected soils. Effects of lime dose on biosolids physical properties were examined by measuring selected physical characteristics of the limed products. Addition of CaO to dewatered biosolids produces heat through the exothermic conversion of CaO to hydrated lime [Ca(OH)2] with only small amounts of heat produced from the exothermic reaction of carbon dioxide (CO2) with Ca(OH)2 to form calcium carbonate (CaCO3). All heat produced was dissipated during heating of the biosolids and evaporation of water. Because of the predominance of Ca(OH)2 in the limed biosolids, care should be taken in using these materials as liming agents and soil amendments because of the very high initial soil pHs (greater than pH 12) that can persist for weeks or more. Increasing lime dose improved the density and water‐holding capacity of biosolids and improved their physical consistency.
Stripping and recovery of ammonia from centrate of anaerobically digested biosolids at elevated temperatures
Authors: Katehis Dimitrios , Diyamandoglu Vasil , Fillos John
Published: September 2006

The process of air stripping/absorption was studied at pilot scale at temperatures ranging between 23 and 75°C using ammonia in artificial and natural centrate. The process was more effective at high temperatures and became pH insensitive beyond a critical pH, which was found to drop as the operating temperature increased. Thus, at high temperatures, shorter packing height and lower pH are required to achieve the same ammonia removal. The Onda correlations predicted well the mass‐transfer properties of 25 mm (1 in.) and 32 mm (1.25 in.) nominal size packing in the ranges of 40 to 60°C and 53 to 61°C, respectively. The Norman/Sherwood–Holloway correlations predicted well the mass‐transfer properties for the former and poorly underpredieted the latter packing. The Onda correlations are recommended for preliminary design of stripping/absorption systems within the preceding temperature ranges.
Knowledge about Conception, Sexual Behavior, and Procurement of Abortion among Female Undergraduate Students in a Nigerian University
Authors: Moronkola O. A. , Amosu A. , Okonkwo C.
Published: September 2006

Of 1,200 questionnaires administered in a cross-sectional study involving University of Ibadan female students, 1000 were found useable for data analysis. Analysis found that a majority of respondents (56.4%) had little knowledge about conception and frequently engaged in sexual intercourse for many reasons, including: to have fun; to show they were mature; and to seek material reward. Also, 61.1% had procured abortion before and most of them did not procure it from government-owned hospitals/clinics, which may likely make them prone to health consequences of unsafe abortion. Part of our recommendations are the need to introduce health education (incorporating sexuality education) into the General Studies Program of the university and that home training on aspects relating to sexuality education be given to and promoted among young people.
Evaluation of a participatory ergonomic intervention aimed at improving musculoskeletal health
Authors: Rivilis Irina , Cole Donald C. , Frazer Mardon B. , Kerr Michael S. , Wells Richard P. , Ibrahim Selahadin
Published: September 2006

Background

Participatory ergonomic (PE) interventions have been increasingly utilized to deal with work‐related musculoskeletal disorders (WMSD).

Methods

Using a longitudinal quasi‐experimental design, a PE process was launched at one depot of a large courier company, with a nearby depot serving as a control. Evaluations focused on 122 employees across the two depots who participated in both pre‐ and post‐questionnaires. An evaluation framework assessed the process of implementation, changes in risk factors, and changes in musculoskeletal health outcomes. Partial and multiple regressions explored the relationships in the evaluation framework.

Results

Changes in work organizational factors had a consistent impact upon changes in health outcomes. Greater participation in the process was associated with increased levels of job influence and communication (P = 0.0059 andP = 0.0940 respectively). Improvements in communication levels were associated with reduced pain intensity and improved work role function (WRF) (P = 0.0077 andP = 0.0248 respectively). Lower levels of pain post‐intervention were related to greater WRF (P = 0.0493).

Conclusions

A PE approach can improve risk factors related to WMSD, and meaningful worker participation in the process is an important aspect for the success of such interventions. Am. J. Ind. Med. 49:801–810, 2006. © 2006 Wiley‐Liss, Inc.
The long and short of it: physical anchoring effects
Authors: LeBoeuf Robyn A. , Shafir Eldar
Published: September 2006

Attempts to reconstruct the magnitude of recently encountered physical stimuli were influenced by the provision of physical anchors. Whether estimating length, weight, or loudness, those increasing the magnitude of a relatively small (short, light, or quiet) physical anchor produced estimates that were reliably lower than did those decreasing the magnitude of a relatively large (long, heavy, or loud) anchor. Estimates produced without an anchor were also low, suggesting that when people physically adjust upwards from a self‐selected starting point, “no anchor” may, in fact, act as a very low anchor. Physical anchors appear to influence estimates of recently encountered physical stimuli, much as numerical anchors influence estimates of more abstract numerical quantities. Implications for processes underlying anchoring, adjustment, and related tasks are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Decreasing household television time: a pilot study of a combined behavioral and environmental intervention
Authors: Gorin Amy , Raynor Hollie , Chula‐Maguire Kim , Wing Rena
Published: September 2006

Excessive TV viewing is associated with weight gain across the lifespan; thus developing strategies to decrease household viewing time may be an effective obesity prevention approach. This pilot study (n = 6 families) examined the feasibility and short‐term impact of a 2‐pronged environmental plus behavioral approach designed to reduce TV time in the entire family. The environmental manipulation involved placing TV Allowances (programmed to turn off power after family members had watched 75% of their baseline hours) on all TVs in the home. A kit with behavioral strategies for reducing TV time was also sent to the home each week and family members self‐monitored viewing time. Viewing was objectively assessed with the TV Allowances at baseline and at 8 weeks. A significant decrease in objectively measured TV viewing hours was observed, t(5) = 3.1, p = 0.03, 29.8 ± 10.3 versus 14.9 ± 6.0 h (equivalent of decreasing from 7.5 to 3.7 h per day). Fifty percent of families reduced their viewing time by ≥50%. The acceptability of the intervention was high, with 100% of families reporting they would recommend the TV Allowances to others. Further research is needed to test the long‐term efficacy of the program and its impact on weight. Copyright © 2006 John Wiley & Sons, Ltd.
Caveolin‐1 polarization in migrating endothelial cells is directed by substrate topology not chemoattractant gradient
Authors: Santilman Virginie , Baran JoAnne , Anand‐Apte Bela , Fox Paul L. , Parat Marie‐Odile
Published: September 2006

Polarization is a hallmark of migrating cells, and an asymmetric distribution of proteins is essential to the migration process. Caveolin‐1 is highly polarized in migrating endothelial cells (EC). Several studies have shown caveolin‐1 accumulation in the front of migrating EC while others report its accumulation in the EC rear. In this paper we address these conflicting results on polarized localization of caveolin‐1. We find evidence for the hypothesis that different modes of locomotion lead to differences in protein polarization. In particular, we show that caveolin‐1 is primarily localized in the rear of cells migrating on a planar substrate, but in the front of cells traversing a three‐dimensional pore. We also show that a chemoattractant, present either as a gradient or ubiquitously in the medium, does not alter caveolin‐1 localization in cells in either mode of locomotion. Thus we conclude that substrate topology, and not the presence of a chemoattractant, directs the polarization of caveolin‐1 in motile ECs. Cell Motil. Cytoskeleton 2006. © 2006 Wiley‐Liss, Inc.
Tau interacts with Golgi membranes and mediates their association with microtubules
Authors: Farah Carole Abi , Perreault Sébastien , Liazoghli Dalinda , Desjardins Mylène , Anton Angela , Lauzon Michel , Paiement Jacques , Leclerc Nicole
Published: September 2006

Tau, a microtubule‐associated protein enriched in the axon, is known to stabilize and promote the formation of microtubules during axonal outgrowth. Several studies have reported that tau was associated with membranes. In the present study, we further characterized the interaction of tau with membranous elements by examining its distribution in subfractions enriched in either Golgi or endoplasmic reticulum membranes isolated from rat brain. A subfraction enriched with markers of the medial Golgi compartment, MG160 and mannosidase II, presented a high tau content indicating that tau was associated with these membranes. Electron microscope morphometry confirmed the enrichment of this subfraction with Golgi membranes. Double‐immunogold labeling experiments conducted on this subfraction showed the direct association of tau with vesicles labeled with either an antibody directed against MG160 or TGN38. The association of tau with the Golgi membranes was further confirmed by immunoisolating Golgi membranes with an anti‐tau antibody. Immunogold labeling confirmed the presence of tau on the Golgi membranes in neurons in vivo. Overexpression of human tau in primary hippocampal neurons induced the formation of large Golgi vesicles that were found in close vicinity to tau‐containing microtubules. This suggested that tau could serve as a link between Golgi membranes and microtubules. Such role for tau was demonstrated in an in vitro reconstitution assay. Finally, our results showed that some tau isoforms present in the Golgi subfraction were phosphorylated at the sites recognized by the phosphorylation‐dependent antibodies PHF‐1 and AT‐8. CellMotil. Cytoskeleton 2006. © 2006 Wiley‐Liss, Inc.
Enhanced remeshing from STL files with applications to surface grid generation
Authors: Wang Desheng , Hassan Oubay , Morgan Kenneth , Weatherill Nigel
Published: September 2006

In this paper, we present a robust and efficient technique for surface meshing based on Stereolithography (STL) surface definition. Ridges are correctly identified using checks on dihedral angle and comparisons of the ratio of triangle edge lengths. Robust edge swapping, splitting and contraction are performed with stringent element validity checks. The improved remeshing technique is applied directly to CAD models and it is also used to improve surface triangulations which are reconstructed from sectional contours extracted from medical images. All the application examples, including the circulatory system and the urinary system, demonstrate that the enhanced remeshing procedure is robust and efficient for surface grid generation. Copyright © 2006 John Wiley & Sons, Ltd.
Optimization of material distribution in functionally graded structures with stress constraints
Authors: Stump Fernando V. , Silva Emílio C. N. , Paulino Glaucio H.
Published: September 2006

This work describes a topology optimization framework to design the material distribution of functionally graded structures considering mechanical stress constraints. The problem of interest consists in minimizing the volumetric density of a material phase subjected to a global stress constraint. Due to the existence of microstructure, the micro‐level stress is considered, which is computed by means of a mechanical concentration factor using a p‐norm of the Von Mises stress criterium (applied to the micro‐level stress). Because a 0–1 (void–solid) material distribution is not being sought, the singularity phenomenon of stress constraint does not occur as long as the material at any point of the medium does not vanish and it varies smoothly between material 1 and material 2. To design a smoothly graded material distribution, a material model based on a non‐linear interpolation of the Hashin–Strikhman upper and lower bounds is considered. Consistently with the framework adopted here in, the so‐called ‘continuous approximation of material distribution’ approach is employed, which considers a continuous distribution of the design variable inside the finite element. As examples, the designs of functionally graded disks subjected to centrifugal body force are presented. The method generates smooth material distributions, which are able to satisfy the stress constraint. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of pattern precision shows that Drosophila segmentation develops substantial independence from gradients of maternal gene products
Authors: Holloway David M. , Harrison Lionel G. , Kosman David , Vanario‐Alonso Carlos E. , Spirov Alexander V.
Published: September 2006

We analyze the relation between maternal gradients and segmentation in Drosophila, by quantifying spatial precision in protein patterns. Segmentation is first seen in the striped expression patterns of the pair‐rule genes, such as even‐skipped (eve). We compare positional precision between Eve and the maternal gradients of Bicoid (Bcd) and Caudal (Cad) proteins, showing that Eve position could be initially specified by the maternal protein concentrations but that these do not have the precision to specify the mature striped pattern of Eve. By using spatial trends, we avoid possible complications in measuring single boundary precision (e.g., gap gene patterns) and can follow how precision changes in time. During nuclear cleavage cycles 13 and 14, we find that Eve becomes increasingly correlated with egg length, whereas Bcd does not. This finding suggests that the change in precision is part of a separation of segmentation from an absolute spatial measure, established by the maternal gradients, to one precise in relative (percent egg length) units. Developmental Dynamics 235:2949–2960, 2006. © 2006 Wiley‐Liss, Inc.
Phases of myogenic cell activation and possible role of dermomyotome cells in teleost muscle formation
Authors: Steinbacher P. , Haslett J.R. , Six M. , Gollmann H.P. , Sänger A.M. , Stoiber W.
Published: September 2006

Present knowledge indicates that fibre recruitment (hyperplasia) in developing teleost fish occurs in three distinct phases. However, the origin and relationship of the myogenic precursors activated during the different phases remains unclear. Here, we address this issue using molecular techniques on embryos and larvae of pearlfish, a large cyprinid species. Results provide comprehensive molecular characterisation of cell recruitment over the three phases of myogenesis, identifying muscle types as they arise. Specifically, we show that the myogenic cells arising during 2nd phase myogenesis are clearly different from the myogenic cells arising during the 3rd phase and that the dermomyotome is a major source of myogenic cells driving 2nd phase hyperplasia. These findings are discussed in relation to their implications for the generality of vertebrate developmental patterns. Developmental Dynamics 235:3132–3143, 2006. © 2006 Wiley‐Liss, Inc.
Ionic Green Solvents from Renewable Resources
Authors: Imperato Giovanni , König Burkhard , Chiappe Cinzia
Published: September 2006

Nature provides a vast new vista of opportunities for the preparation of new recyclable solvents. Natural compounds have been recently used to prepare the cationic or anionic moiety of room‐temperature ionic liquids. In many cases, these new solvents, based on modifications of natural products, contain chiral centres and/or specific functional groups. This paper is an overview in an area of research that is destined for rapid development and expansion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Intergroup contact and intergroup attitudes: a longitudinal study
Authors: Brown Rupert , Eller Anja , Leeds Sarah , Stace Kim
Published: September 2006

A longitudinal study (N = 109) of interschool contact and attitudes was conducted to test Allport's (1954) Contact Hypothesis and Brown and Hewstone's (2005) addendum to it on the moderating role of typicality in the contact‐attitude relationship. Three different measures of intergroup attitude were employed, including a new measure of infrahumanisation (Leyens et al., 2000). Support for the hypotheses was found on all three measures in the longitudinal analyses. Quantity of contact with a member of the outgroup was consistently associated with more favourable attitudes towards the outgroup as a whole. Importantly, contact was found to predict attitude but the reverse causal path was not significant. Also, on one measure there was an indication that the effects of contact quality were more beneficial when the contact persons were seen as typical of the outgroup than when they were not. It is concluded that, as originally hypothesised by Allport, contact with members of an outgroup can improve intergroup attitudes, but especially if those people can be seen as representative of their group. Copyright © 2006 John Wiley & Sons, Ltd.
An improved gel‐based DNA microarray method for detecting single nucleotide mismatch
Authors: Xiao Peng Feng , Cheng Lu , Wan Yuan , Sun Bei Li , Chen Zao Zao , Zhang Sheng You , Zhang Chung Ziu , Zhou Guo Hua , Lu Zu Hong
Published: September 2006

3‐D polyacrylamide gel‐based DNA microarray platforms provide a high capacity for nucleic acids immobilization and a solution‐mimicking environment for hybridization. However, several technological bottlenecks still remain in these platforms, such as difficult microarray preparation and high fluorescent background, which limit their application. In this study, two new approaches have been developed to improve the convenience in microarray preparation and to reduce the background after hybridization. To control the polymerization process, solutions containing acrylamide‐modified oligonucleotide, acrylamide, glycerol and ammonium persulfate are spotted onto a functionalized glass slide, and then the slide is transferred to a vacuum chamber with TEMED, so that TEMED is vaporized and diffused into the spots to induce polymerization. By applying an electric field across a hybridized microarray to remove the nonspecifically bound labeled targets, this approach can solve the problem of high fluorescent background of the gel‐based microarray after hybridization. Experimental results show that our immobilization method can be used to construct high quality microarrays and exhibits good reproducibility. Moreover, the polymerization is not affected by PCR medium, so that PCR products can be used for microarray construction without being treated by commercial purification cartridges. Electrophoresis can improve the signal‐to‐noise significantly and has the ability to differentiate single nucleotide variation between two homozygotes and a heterozygote. Our results demonstrated that this is a reliable novel method for high‐throughput mutation analysis and disease diagnosis.
QSNPlite, a software system for quantitative analysis of SNPs based on capillary array SSCP analysis
Authors: Tahira Tomoko , Okazaki Yuko , Miura Kenichi , Yoshinaga Aki , Masumoto Kazumi , Higasa Koichiro , Kukita Yoji , Hayashi Kenshi
Published: September 2006

We present a newly developed software called “QSNPlite” that comprehensively interprets the data of SSCP and sequencing analyses obtained from capillary array electrophoresis systems used in the quantitative characterization of SNPs. QSNPlite assists in the genotyping of individuals with SNPs and in estimating the allele frequencies of SNPs using pooled DNA. We show that this estimation is accurate (mean absolute error, 1.4%) by comparing the results of the pooled analysis using QSNPlite with the true frequencies based on the allele counting after performing individual genotypings. The QSNPlite program runs on Windows XP and can be used to determine the allele frequencies of SNPs among a large number of individuals, such as in association studies of disease‐responsible genes using the candidate gene approach.
Where is all the pressure coming from? Messages from mothers and teachers about preschool children's appearance, diet and exercise
Authors: McCabe Marita P. , Ricciardelli Lina A. , Stanford Jacqueline , Holt Kate , Keegan Salley , Miller Louise
Published: September 2006

This study used interviews and qualitative analyses to investigate the nature of the messages that preschool children receive from mothers and teachers about their bodies, general appearance, exercise and eating practices. Participants were 10 female teachers and 53 mothers. The behaviours of the 53 children (24 boys, 29 girls) were also observed to determine the nature of their eating and exercise behaviours. The results demonstrated that both mothers and teachers expressed concerns about their own bodies. Mothers also communicated messages to their daughters about losing weight and messages to their sons about increasing their muscles. Both girls and boys were concerned about their appearance, particularly their clothes and hair. Girls also demonstrated some concerns about losing weight, and boys with increasing muscles. Implications of these results are discussed in terms of designing education programs for mothers, teachers and children to prevent the development of body image concerns and disordered eating among children. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.