bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequencing batch reactor (SBR) as optimal method for production of granular activated sludge (GAS) – fluid dynamic investigations
Authors: Zima B.E. , Díez L. , Kowalczyk W. , Delgado A.
Published: April 2007

Fluid dynamic investigations of multiphase flow (fluid, air, granules) in a sequencing batch reactor (SBR) are presented. SBR can be considered as an attractive technology for cultivation of granular activated sludge (GAS). Granulation is a complicated process and its mechanism is not fully understood yet. Many factors influence the formation and structure of aerobic granular sludge in a bioreactor. Extracellular polymer substances (EPS) and superficial gas velocity (SGV) play a crucial role for granules formation. Additionally, it is supposed that EPS production is stimulated by mechanical forces. It is also assumed that hydrodynamic effects have a major influence on the formation, shape and size of GAS in SBR under aerobic condition. However, the influence of stress on granulation is poorly investigated. Thus, in the present paper, fluid dynamic investigations of multiphase flow in a SBR, particularly effect of normal and shear strain, are reported. In order to analyse multiphase flow in the SBR, optical in-situ techniques with particle image velocimetry (PIV) and particle tracking velocimetry (PTV) are implemented. Obtained results show a characteristic flow pattern in a SBR. It is pointed out that additional effects like particle-wall collisions, inter particle collisions, erosion can also affect significantly granules formation.
Influence of temperature on microbial colonisation of clayey schist as a support media of a submerged filter for groundwater denitrification
Authors: De la Rúa A. , Rodelas B. , González-López J. , Gómez M.A.
Published: April 2007

The effect of temperature on biofilm formation and denitrification activity was evaluated. Assays were made in a lab-scale submerged filter for the denitrification of polluted groundwater, with and without a previous inoculation. The inoculation was carried out with a selected strain of Pseudomonas mandelii. Different temperatures were tested: 5, 10, 20 and 30 °C. Biofilm observations were made, and monitoring of the denitrification capacity of the system was maintained during the experiment. Our results showed that both colonisation of the support material of the filter and biofilm maturity have a dependency with temperature, with an optimum temperature of 20 °C if the system was previously inoculated with the Pseudomonas mandelii strain. For a correct achievement of the denitrification process, a previous inoculation of the system is essential. Although the development of a biofilm from the natural microbiota present in the groundwater is possible, it is not capable to adequately denitrify polluted groundwater. In terms of the correct achievement of the denitrification process, temperature affects the operation of the system at cold environments, although the use of Pseudomonas mandelii strain A103 allows denitrification at 10–30 °C with very good results (above 90% removal), affecting only to the time needed for the stabilisation of the system.
Modelling the competition of planktonic and sessile aerobic heterotrophs for complementary nutrients in biofilm reactor
Authors: Lu T. , Saikaly P.E. , Oerther D.B.
Published: April 2007

A comprehensive, simplified microbial biofilm model was developed to evaluate the impact of bioreactor operating parameters on changes in microbial population abundance. Biofilm simulations were conducted using three special cases: fully penetrated, internal mass transfer resistance and external mass transfer resistance. The results of model simulations showed that for certain operating conditions, competition for growth limiting nutrients generated oscillations in the abundance of planktonic and sessile microbial populations. These oscillations resulted in the violation of the competitive exclusion principle where the number of microbial populations was greater than the number of growth limiting nutrients. However, the operating conditions which impacted microbial community diversity were different for the three special cases. Comparing the results of model simulations for dispersed-growth, biofilms and bioflocs showed that oscillations and microbial community diversity were a function of competition as well as other key features of the ecosystem. The significance of the current study is that it is the first to examine competition as a mechanism for controlling microbial community diversity in biofilm reactors.
Modelling biofilm-modified hydrodynamics in 3D
Authors: Graf von der Schulenburg D.A. , Gladden L.F. , Johns M.L.
Published: April 2007

A simulation–based study to predict the impact of biofilm growth on displacement distributions for flow of water through a supporting packed bed is presented. The lattice Boltzmann method and a directed random walk algorithm are used, and are applied to the system with and without biofilm being present. The aim of this simulation study is to model the anomalous transport dynamics induced by biofilm, as reported in the literature, and thus to study the impact of observation time, Δ, on the shape of the displacement distributions (propagators). We believe that this is the first demonstration of a propagator simulation for flow through a complex porous structure modulated by biofilm growth. The propagator distributions undergo a transition from a pre-asymptotic to a Gaussian-shaped distribution with increasing Δ. The propagators were simulated for a wide range of Δ going up to 500 seconds. This transition occurs with and without biofilm, but is very significantly delayed when biofilm is present due to the consequential development of essentially stagnant regions. The transition can be classified into three stages: a diffusion-dominated stage, a “twin-peak” stage and an advection-dominated stage.
Experimental and simulation analysis of community structure of nitrifying bacteria in a membrane-aerated biofilm
Authors: Matsumoto S. , Terada A. , Aoi Y. , Tsuneda S. , Alpkvist E. , Picioreanu C. , van Loosdrecht M.C.M.
Published: April 2007

Until now, only few attempts have been made to assess biofilm models simulating microenvironments in a biofilm. As a first step, we compare the microenvironment observed in a membrane aerated biofilm (MAB) to that derived from a two-dimensional computational model with individual ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) embedded in a continuum EPS matrix. Gradients of oxygen were determined by means of microelectrodes. The change in nitrifying bacterial populations with the biofilm depth was quantified using fluorescence in situ hybridization (FISH) in combination with a confocal laser scanning microscopy (CLSM). Microelectrode measurements revealed that oxic and anoxic or anaerobic regions exist within the MAB. The oxygen profile predicted by the model showed good agreement with that obtained by microelectrode measurements. The oxic part of the biofilm was dominated by NSO190 probe-hybridized AOB, which formed relatively large clusters of cells directly on the membrane surface, and by the NOB belonging to genus Nitrobacter sp. On the other hand, NOB belonging to genus Nitrospira sp. were abundant at the oxic-anoxic interface. The model prediction regarding AOB and Nitrobacter sp. distribution was consistent with the experimental counterpart. Measurements of AOB cluster size distribution showed that colonies are slightly larger adjacent to the membrane than at the inner part of the biofilm. The sizes predicted by the current model are larger than those obtained in the experiment, leading to the arguments that some factors not contained in the model would affect the cluster size.
A biofilm model for engineering design
Authors: Takács I. , Bye C.M. , Chapman K. , Dold P.L. , Fairlamb P.M. , Jones R.M.
Published: April 2007

A biofilm model is presented for process engineering purposes – wastewater treatment plant design, upgrade and optimisation. The model belongs in the 1D dynamic layered biofilm model category, with modifications that allow it to be used with one parameter set for a large range of process situations. The biofilm model is integrated with a general activated sludge/anaerobic digestion model combined with a chemical equilibrium, precipitation and pH module. This allows the model to simulate the complex interactions that occur in the aerobic, anoxic and anaerobic layers of the biofilm. The model has been tested and is shown to match a variety of design guidelines, as well as experimental results from batch testing and full-scale plant operation. Both moving bed bioreactors (MBBR) and integrated fixed film activated sludge (IFAS) systems were simulated using the same model and parameter set. A new steady-state solver generates fast solutions and allows interactive design work with the complex model.
Use of fluorescent in situ hybridisation for the visualisation of Helicobacter pylori in real drinking water biofilms
Authors: Bragança S.M. , Azevedo N.F. , Simões L.C. , Keevil C.W. , Vieira M.J.
Published: April 2007

A fluorescently labelled peptide nucleic acid (PNA) probe has been applied for the in situ detection of Helicobacter pylori in drinking water biofilms. The method was originally applied to real pipe samples removed from a drinking water distribution system (DWDS) but the curvature and the heavy fouling of the pipes prevented an accurate detection of the bacterium by epifluorescence microscopy. Therefore, two semi-circular flow cells were placed in a bypass of the DWDS, and coupons with up to 72 days of exposure were regularly sampled and analysed for the presence of H. pylori. In the flat surfaces of the coupons, it was possible to sparsely detect cells exhibiting similar morphology to H. pylori that were emitting the PNA probe fluorescent signal. Coupons were also visualised under the microscope before the hybridisation procedure to serve as negative controls and ensure the validity of the method. This work corroborates the findings already published elsewhere that this bacterium might be present in DWDS biofilms. The method requires, however, highly trained personnel for an accurate detection of the pathogen and will need simplification before being routinely used in standard water analysis laboratories.
An ecology-based analysis of irreversible biofouling in membrane bioreactors
Authors: Zhang K. , Choi H. , Wu M. , Sorial G.A. , Dionysiou D. , Oerther D.B.
Published: April 2007

To provide the first step towards a microbial ecology-based understanding of irreversible membrane biofouling, four laboratory-scale membrane bioreactors (MBRs) were operated to investigate the identity of bacterial populations highly correlated with irreversible membrane biofouling. The conventional MBR was divided into two separate experimental units. Unit one consisted of four suspended-growth, activated sludge, sequencing batch bioreactors treating a synthetic paper mill wastewater. Unit two consisted of a microfiltration membrane cell. Amplified ribosomal deoxyribonucleic acid restriction analysis (ARDRA) was used to compare the predominant bacterial populations in samples of mixed liquor and irreversibly bound to the membrane surface. The results of ARDRA showed a significant difference between the planktonic and sessile bacterial communities suggesting that irreversible biofouling of microfiltration membranes may be more highly correlated to specific bacterial populations rather than the total, bulk concentration of biomass. A custom-built mini-flow cell and light microscopy were used to visualise the early formation of biofilms by two pure cultures (Escherichia coli and Acinetobacter calcoaceticus) on membrane surfaces. The results confirmed that A. calcoaceticus was able to enhance the initiation of biofilm formation on microfiltration membranes.
The rate of iron corrosion for different organic carbon sources during biofilm formation
Authors: Park S.-K. , Choi S.-C. , Kim Y.-K.
Published: April 2007

The effects of total organic carbon and biofilm on microbial corrosion were quantified using serum bottles in a 2×2 factorial design. Both organic carbon and biofilm bacteria had a significant effect on the iron corrosion rate, irrespective of the levels of the other variable (p=0.05). There was no evidence of interaction between organic carbon and biofilm bacteria. Within the tested levels, the addition of exogenous organic carbon increased the corrosion rate by an average of 3.838 mg dm−2 day−1 (mdd), but the presence of biofilm bacteria decreased the rate by an average of 2.305 mdd. More iron was released from the coupon in response to organic carbon. Powder x-ray diffractometry indicated that the scales deposited on the corroded iron surface consisted primarily of lepidocrocite (γ-FeOOH), magnetite (Fe3O4) and hematite (α-Fe2O3). Corrosion rates by different organic carbon sources, i.e. acetate, glucose and humic substances, were compared using an annular biofilm reactor. One-way ANOVA suggested that the effect of each carbon source on corrosion was not the same, with the iron corrosion rate highest for glucose, followed by acetate, humic substances and the control. Magnetite was a major constituent of the corrosion products scraped from iron slides. Examination of community-level physiological profile patterns on the biofilms indicated that acetate was a carbon source that could promote the metabolic and functional potentials of biofilm communities.
Neuromuscular Training Versus Strength Training During First 6 Months After Anterior Cruciate Ligament Reconstruction: A Randomized Clinical Trial
Authors: Risberg May Arna , Holm Inger , Myklebust Grethe , Engebretsen Lars
Published: April 2007

Background and Purpose

The purpose of this study was to determine the effect of a 6-month neuromuscular training (NT) program versus a traditional strength training (ST) program following anterior cruciate ligament (ACL) reconstruction.

Subjects

Seventy-four subjects with ACL reconstruction participated in the study.

Methods

The study was a randomized, single-blinded, controlled trial. The NT and ST groups were tested preoperatively and at 3 and 6 months. The main outcome measure was the Cincinnati Knee Score. Secondary outcome measures were visual analog scales (VASs) for pain and function, the 36-Item Short-Form Health Survey (SF-36), hop tests, isokinetic muscle strength, proprioception, and static and dynamic balance tests.

Results

The NT group demonstrated significantly improved Cincinnati Knee Scores and VAS scores for global knee function compared with the ST group at the 6-month follow-up. There were no significant differences between the groups for the other outcome measures (ie, hop, balance, proprioception, and muscle strength tests).

Discussion and Conclusion

The results of this study suggest that exercises included in the NT program should be part of the rehabilitation program following ACL reconstruction.
Differential Diagnosis of Endometriosis in a Young Adult Woman With Nonspecific Low Back Pain
Authors: Troyer Mark R
Published: April 2007

Background and Purpose

Endometriosis is a common gynecological disorder that can cause musculoskeletal symptoms and manifest as nonspecific low back pain.

Case Description

The patient was a 25-year-old woman who reported the sudden onset of severe left-sided lumbosacral, lower quadrant, buttock, and thigh pain. The physical therapist examination revealed findings suggestive of a pelvic visceral disorder during the diagnostic process. The physical therapist referred the patient for medical consultation, and she was later diagnosed by a gynecologist with endometriosis and a left ovarian cyst.

Outcomes

The patient underwent laser laparoscopy and excision of the ovarian cyst followed by a regimen of gonadotropin-releasing hormone agonists. The intervention resulted in abolition of the lower quadrant pain and a significant reduction of the back and leg pain that enabled the patient to return to her normal activities.

Discussion

A thorough physical therapist examination that considers all of the musculoskeletal, visceral, and psychosocial components is essential to identify pelvic disorders such as endometriosis and other disease processes during the differential diagnosis of nonspecific low back pain. Medical consultation is necessary to provide proper diagnosis and intervention of endometriosis, but physical therapists also may have an important role in the identification of endometriosis and the management of the musculoskeletal aspects of the disorder.
Contingent Valuation: Comparing Participant Performance in Group-Based Approaches and Personal Interviews
Authors: Lienhoop Nele , Macmillan Douglas C.
Published: April 2007

This paper reports a Contingent Valuation application to estimate the non-market costs and benefits of hydro scheme developments in an Icelandic wilderness area. A deliberative group-based approach, called Market Stall, is compared to a control group consisting of conventional in-person interviews, in order to investigate flaws of Contingent Valuation, such as poor validity and protest responses. Perceived property rights suggested the use of willingness-to-accept in compensation for wilderness loss and willingness-to-pay for hydro scheme benefits. The study is novel as it applies participant behaviour observation to gain insights into the shortcomings of conventional data collection modes. Main drawbacks with in-person interviews were found to be low motivation, standardised information and time pressure which hindered individuals from carefully considering their preferences. Market Stall performed better in the study: welfare estimates were more easily explained by socio-economic variables, the non-response rate was lower, and respondents were more engaged. Our research findings also suggest that participant behaviour can be used to supplement conventional validity tests.
An Inquiry concerning the Acceptance of Intrinsic Value Theories of Nature
Authors: Butler W.F. , Acott T.G.
Published: April 2007

This study empirically assesses the extent to which intrinsic value theories of nature are accepted and acknowledged outside the realm of academic environmental ethics. It focuses on twenty of the largest landowning organisations in England, including both conservation and non-conservation organisations and investigates the environmental philosophical beliefs and values held by representative individuals of these groups. An in-depth interview was held with a representative from each organisation. The interviews were analysed using qualitative data analysis software and the results compared against a backdrop of academic philosophical positions. The study found that an ecocentric position which acknowledges nature's intrinsic value was adopted by the majority of respondents, both from conservation and non-conservation organisations. However, it was also found that individuals felt the idea of nature's intrinsic value was generally not reflected in organisational policy.
Territorial Equity and Sustainable Development
Authors: Zuindeau Bertrand
Published: April 2007

The sustainable development (SD) issue is mainly focused on questions of intergenerational equity. The study of intragenerational equity is less common. In this article, I am interested in a particular kind of intragenerational equity, territorial equity. As well as exposing the various territorial inequalities, the literature on SD comprehends territorial equity through possible territorial transfers of sustainability. The reality of these transfers and how to measure them are however, very directly dependent on general conceptions of SD. The text examines analyses that may be inferred from these different ideas. It attempts to reveal the respective limits and to propose a synthesis, which incorporates operational objectives.
Water Dreams, Earthen Histories: Exploring Urban Environmental History at the Penrith Lakes Scheme and Castlereagh, Sydney
Authors: Karskens Grace
Published: April 2007

Urban environmental history comprises both human and ecological experience; the two were and are inseparable, and their interaction is dynamic. This essay explores the human and bioregional history of the Penrith Lakes Scheme at Castlereagh in outer Western Sydney as a case study in integrating the two approaches. Conceived in the late 1960s, the Scheme is a quintessential 'hybrid landscape', aiming to rehabilitate 2,000 hectares of open-cut gravel quarries by creating huge artificial lakes and landforms. But it destroyed a rich palimpsest of earlier farming and Aboriginal landscapes, both of which had also transformed the environment. By focusing on this place over time, it is possible to track the succession of Aboriginal, settler, industrial and urban histories, to explore the shifting meanings of this environment, the different ways they knew and shaped this country, and the politics and strategic uses of different types of environmental knowledge.
The Superstars
Authors: Puglisi Luigi Prestinenza
Published: April 2007

In recent years, the over‐intellectualisation of architecture has detached it ‘from its experiential, embodied and emotive ground’. Juhani Pallasmaa provides a template for architecture and landscape design that enables a stronger continuum between our outer and inner landscapes, drawing on historic and modern artistic inspirations alike. Copyright © 2007 John Wiley & Sons, Ltd.
The World's Biggest Sculptor: The Architecture of Massimiliano Fuksas
Authors: Casciani Stefano
Published: April 2007

At the start of the new millennium, Massimiliano Fuksas was one of the most significant Italian architects working outside his home country. His reputation in Italy and abroad, however, was taken to a further level by his completion of the New Milan Trade Fair. Stefano Casciani, an ex‐student of Fuksas, provides an insightful and intriguing account of his ‘old’ professor: a robust and seemingly contradictory figure who is capable of great voluminous expression and delicacy. Casciani also finds constancy in his unrelenting energy, freshness and wit. Copyright © 2007 John Wiley & Sons, Ltd.
The Middle Generation
Authors: Puglisi Luigi Prestinenza
Published: April 2007

Victoria Marshall and Brian McGrath have developed and transferred the ecological model of ‘patch dynamics’ to urban landscape design. It is an approach that stresses the resilient, flexible and adaptable nature of cities, interacting with a ‘notion of disturbance ecology rather than a benign nature’. Here they apply their design approach to Hoboken, on the New Jersey Gold Coast, which, only a hop and a skip from Manhattan, directly across the Hudson from the Financial District, remains culturally and economically diverse. Copyright © 2007 John Wiley & Sons, Ltd.
Arlotti‐Beccu‐Desideri‐Raimondo
Authors: Locci Massimo
Published: April 2007

Currently one of the most active offices in Rome, Arlotti‐Beccu‐Desideri‐Raimondo (ABDR) has seven major projects under way or at the point of completion. Massimo Locci explains why, despite being theoretically and methodologically rigorous, the practice's work cannot be readily categorised. Unique in its combination of a purist Modernist language with an aptitude for expressive informality, the office is also proactive in its adoption of bioclimatic technologies and its understanding of new communication models. Copyright © 2007 John Wiley & Sons, Ltd.
The Young Generation
Authors: Puglisi Luigi Prestinenza
Published: April 2007

In August 2005, 80 per cent of New Orleans was devastated by flood damage precipitated by Hurricane Katrina. Christiana Spens was on a college exchange in Memphis when the hurricane hit. Here she gives her impressions of the city in the wake of the storm. Copyright © 2007 John Wiley & Sons, Ltd.
The Young Experimentalists
Authors: Baldini Anna
Published: April 2007

Experimental architecture in Italy began to take a new form in the 1990s when young architects, who were embracing new digital technologies, also began to go abroad to study and practise in greater numbers. Anna Baldini outlines a fecund strand in Italian architecture which, while no longer wholly new or youthful, retains its vitality. She highlights, in particular, the contributions of: Avatar Architettura, Gianluca Brini, Elastico spa+3, Exposure Architects, Giuliano Fausti, Luisa Fontana, Giorgio Goffi, ian+, Iotti+Pavarani Architetti, Fabrizio Leoni, ma0/emmeazero, Antonella Mari, Metrogramma, Open Building Research (OBR), RoccAtelier, studio.eu and Vulcanica Achitettura. Copyright © 2007 John Wiley & Sons, Ltd.
Young Romans: ‘Fully, Not Partially Controlled’
Authors: Mosco Valerio Paolo
Published: April 2007

RM008 is a loose grouping of eight young practices in Rome, encompassing: Centola & Associati, De Logu Associati, Giammetta & Giammetta Architettura, King Roselli Architetti, n!Studio, Nemesi Studio, t‐studio and Labics. Valerio Paolo Mosco describes the various characteristics of this disparate but savvy group of young offices that have conjoined in a bid for greater visibility and publicity. Copyright © 2007 John Wiley & Sons, Ltd.
The Young Sensualists
Authors: Scaglione Pino
Published: April 2007

Pino Scaglione perceives a new sensuality at play in Italy. He takes us on a tour that takes in the elegant and sober forms of +Arch's new headquarters for Dolce & Gabbana in Milan and the highly original new soccer stadium in Siena by Iotti + Pavarani. Heading south he highlights some remarkable new architecture in Naples, Sardinia and Sicily injected with a rare poetic sensibility. Copyright © 2007 John Wiley & Sons, Ltd.
Radical Italian Architecture Yesterday and Today
Authors: Menking William , Kazi Olympia
Published: April 2007

In Italy there is a revival of the spirit of 1960s Radicalism. Fresh from university, young architects ‘pick up a rock band name, enrol in an architectural competition or just invent their own research and project installations’. William Menking, who co‐curated the 2003 exhibition at London's Design Museum on Superstudio ‐ the supergroup of Italian radicali ‐ and Olympia Kazi bring the new generation of young protagonists under scrutiny. Copyright © 2007 John Wiley & Sons, Ltd.
The Italian Architectural Press
Authors: Croci Valentina
Published: April 2007

The proliferation of architectural media in Italy is prodigious. Valentina Croci describes the history behind the plethora of printed magazines, outlining the background and approach of the most prestigious titles. What does the future hold for such a large number of specialist publications? Are they to be eclipsed by the numerous new electronic newsletters and websites? Copyright © 2007 John Wiley & Sons, Ltd.
Yale Art Gallery
Authors: Merkel Jayne
Published: April 2007

Rarely does the first major work of an iconic architect face his last major work, in the same building type, open to the public, free of charge, and in excellent condition. Louis I Kahn's seminal, recently restored addition to the Yale University Art Gallery is just across Chapel Street from his Yale Center for British Art. Jayne Merkel describes the interiors of these mid‐20th‐century modern masterpieces and the recent Herculean efforts to return them to Kahn's intentions while making them suitable for the preservation, study and exhibition of art according to 21st‐century standards. Copyright © 2007 John Wiley & Sons, Ltd.
Dose‐related subclinical neurobehavioral effects of chronic exposure to low levels of organic solvents
Authors: Bleecker Margit L. , Bolla Karen I. , Agnew Jacqueline , Schwartz Brian S. , Ford D. Patrick
Published: April 2007

One hundred eight‐seven workers (mean age ± SD; 42 ± 8.8 years) in two paint manufacturing plants were examined to determine if sustained low‐level exposure to mixed organic solvents resulted in the painters' syndrome (a psycho‐organic syndrome). The test battery consisted of a medical and occupational questionnaire, the Present State Examination, the Zung Depression Scale, the Scandinavian Questionnaire 16, a neu‐ropsychological battery, and vibration thresholds. Solvent exposure, expressed as total hydrocarbon of combined selected solvents, was quantitated using 13–15 years of personal breathing zone samplings. Linear regression analysis controlling for several confounding variables demonstrated significant correlations between increasing exposure to mixed organic solvents and neurobehavioral performance for vibration threshold and several neuropsychological tests. Dose‐related effects of chronic solvent exposure on neurobehavioral outcomes (all subclinical) were shown, but “typical” symptoms characteristic of the painter's syndrome were not found.
Work‐related deaths in children
Authors: Suruda Anthony , Halperin William
Published: April 2007

An analysis of OSHA fatality investigations for 1984–1987 found 104 work‐related deaths in children. The largest category (30%) involved industrial vehicles and equipment. followed by electrocution (17%) and falls (11%). Forty‐three deaths (41%) occurred while engaged in types of work prohibited for children by the Fair Labor Standards Act (FLSA). Three deaths involved work with conveyors, an activity currently permitted for child workers under FLSA. OSHA issued citations for safety violations in 70% of deaths. Since OSHA investigates only some work‐related deaths, the actual number of child labor fatalities during the four year period was probably higher. Using information from OSHA and from death certificate data, we estimate that there are at least 100 work‐related deaths in the United States in children under 18 each year. Hazardous child labor continues to occur even in industries regulated by OSHA and FLSA.
Parental occupational exposures and risk of childhood cancer: A review
Authors: O'Leary Lindy M. , Hicks Anthony M. , Peters John M. , London Stephanie
Published: April 2007

We reviewed the literature in order to summarize the present knowledge on the association between parental occupational exposures to chemicals and the risk of childhood malignancy. The 32 studies pertaining to this topic were evaluated by considering various study qualities such as sample size, specificity of outcome, confounding, exposure specificity, and control selection. When evaluating the findings from any epidemiologic study, the potential sources of bias have to be considered. The selection of subjects, misclassification of exposure or outcome, and confounding from extraneous factors can contribute to a biased estimate of effect. Studies done to minimize these potential biases will be more valid, and these studies should be given the most weight when parental occupational exposures are evaluated as risk factors for childhood malignancy. We conclude that the preponderance of evidence supports the hypothesis that occupational exposure of parents to chemicals increases the risk of childhood malignancy. The parental occupational exposures implicated in childhood malignancy risk are exposure to chemicals including paints, petroleum products, solvents (especially chlorinated hydrocarbons) and pesticides, and exposure to metals. The available data do not allow the identification of specific etiologic agents within these categories of compounds. Future epidemiologic and toxicologic studies should be designed to pursue these leads.
Irritative symptoms and exposure to mineral wool
Authors: Petersen Rolf , Sabroe Svend
Published: April 2007

In a cross‐sectional study undertaken in 1981 using a postal questionnaire, the prevalence of irritative symptoMS was investigated among 2,654 Danish construction workers working with mineral wool. An evaluation was undertaken in a multivariate logit analysis of the relationship between exposure level (measured by hours of exposure to mineral wool per month) and prevalence of symptoMS. The analysis controlled for the confounders of age, smoking habits, and exposure to organic solvents. With greater exposure to mineral wool, there was a statistically significant increase in the frequency of irritative symptoMS from the eyes, the skin, and the upper respiratory tract. Among construction workers working with mineral wool 160–180 hours per month, two‐thirds had these symptoMS once a week or oftener. The occurrence was 2–3 times higher compared with the construction workers not working with mineral wool. The relationship between exposure to mineral wool and skin and mucous membrane symptoMS may be explained by the irritative action of the fibers that are given off during insulation work.
Development, use, and availability of a job exposure matrix based on national occupational hazard survey data
Authors: Sieber W. Karl , Sundin David S. , Frazier Todd M. , Robinson Cynthia F.
Published: April 2007

A job exposure matrix has been developed based on potential exposure data collected during the 1972–1974 National Occupational Hazard Survey (NOHS). The survey sample was representative of all U.S. non‐agricultural businesses covered under the Occupational Safety and Health Act of 1970 and employing eight or more employees. Potential worker exposure to all chemical, physical, or biological agents was recorded during the field survey if certain minimum guidelines for exposure were met. The job exposure matrix (JEM) itself is a computerized database that assists the user in determining potential chemical or physical exposures in occupational settings. We describe the structure and possible uses of the job exposure matrix. In one example, potential occupational exposures to elemental lead were grouped by industry and occupation. In a second example, the matrix was used to determine exposure classifications in a hypothetical case‐control study. Present availability as well as future enhancements of the job exposure matrix are described.
A cross‐sectional study of hand/wrist symptoms in female grocery checkers
Authors: Morgenstern Hal , Kelsh Michael , Kraus Jess , Margolis Wendy
Published: April 2007

A questionnaire was mailed, in 1986, to 1,345 grocery checkers who belonged to one union local in south‐central California. Among the 1,058 female respondents (82% response rate), we found a 12% prevalence of hand/wrist symptoms characteristic of carpal tunnel syndrome (CTS). Symptom prevalence was positively associated with age, average work hours per week, years worked as a checker, and use of diuretics. The estimated effect of years worked as a checker was greater for younger subjects than for older subjects, in whom the association reversed, suggesting the selective loss of symptomatic workers from their jobs (a form of the healthy‐worker effect). Although no effects were found for specific job‐related activities, we estimate that CTS symptoms in at least three of every five symptomatic workers were attributable to occupational exposures.
Testicular cancer in young men and parental occupational exposure
Authors: Kardaun Jan W. P. F. , Hayes Richard B. , Pottern Linda M. , Brown Linda Morris , Hoover Robert N.
Published: April 2007

To investigate whether parental occupation, especially during the 12 month period before birth, could be responsible for elevated rates of testicular cancer in young men, we used data from a case‐control study of 223 cases and 212 controls conducted in the Washington, DC area. For all histologic types of testicular cancer combined, no significant associations were found for specific occupations, nor for the broad occupational categories of professional, other white collar, or blue collar workers. However, for cases with seminomas, excess risks were seen for those with parents employed in the following occupations: mothers in health‐related occupations, O.R. = 4.6 (1.1–19.1), and fathers working in automobile service stations, O.R. = 4.0 (0.6–24.5), manufacturing industries, O.R. = 2.2 (1.0–4.2), and aircraft production and maintenance, O.R. = 5.3 (0.7–24.1), Although these findings for seminoma are intriguing, they do not explain the increase of testicular cancer in young men.
Occupational and environmental health in Eastern Europe: Challenges and opportunities
Authors: Frumkin Howard , Levy Barry S. , Levenstein Charles
Published: April 2007

As the nations of Eastern Europe undergo political and economic transitions, they face considerable occupational and environmental health challenges. Although occupational health services are relatively well developed, environmental health services and policies are not. There are major needs in the areas of education and training, supplies and equipment, and policy development. In addition, privatization poses a variety of new challenges and dangers to occupational and environmental health. This commentary discusses the challenges that face Eastern European nations, and describes opportunities for collaboration among scientists, policymakers, labor, management, and community groups in the United States and Eastern Europe.
Mortality of employed men and women
Authors: Goldblatt Peter , Fox John , Leon David
Published: April 2007

This paper presents mortality data for a 1% sample of men and women in England and Wales who were employed at the time of the 1971 Census of Population. It provides background information on the “healthy worker effect” by age, social class (as determined by occupation), cause of death, and length of follow‐up.

As expected, relative mortality of those employed at census rose with subsequent follow‐up. This effect was strongly age‐related, apparently as a consequence of the development (and increasing predominance) of chronic diseases with age. This suggests a unified explanation for some of the variation described in the literature.

Statistical modelling of the relationship between mortality and length of follow‐up confirmed that the healthy worker effect did not entirely disappear as follow‐up progressed in this study. We examined social background as an explanation for this persistently low mortality, but found no evidence to suggest that it was an important factor.
A longitudinal study of pulmonary function in fire fighters
Authors: Tepper Allison , Comstock George W. , Levine Marshal
Published: April 2007

Pulmonary function changes among fire fighters were evaluated by re‐examining 632 Baltimore city fire fighters six to ten years after a baseline examination. Spirometry was used to determine forced expiratory volume in 1 second (FEV1). Information about exposures was obtained by questionnaire and by combining data from fire department records regarding the number of fires fought by fire fighting units with individual work histories. Men who never wore a mask while extinguishing fires experienced a 1.7 times greater rate of FEV1 decline than mask wearers. Men with ammonia exposure experienced a rate of decline 1.7 times greater than non‐exposed men. Neither length of time spent in exposed jobs nor number of responses were associated with the rate of decline. Active fire fighters experienced a rate of decline 2.5 times greater than those who had retired or resigned. Some effects differed between men who were able to perform repeatable pulmonary function tests and those who were not.
An industry‐wide epidemiologic study of vinyl chloride workers, 1942–1982
Authors: Wong Otto , Whorton M. Donald , Foliart Donna E. , Ragland David
Published: April 2007

The cohort consisted of 10,173 men who had worked for at least one year in jobs involving exposure to vinyl chloride prior to 1 January 1973. These men were employed at 37 plants in the U.S., belonging to 17 companies. Observation of the mortality experience of the cohort was updated from 31 December 1972 to 31 December 1982 (the study now covering 1942–1982). A total of 1,536 cohort members were identified as having died. The observed mortality, by cause, was compared with the expected based on U.S. mortality rates, standardized for age, race, and calendar time. Analyses by length of exposure, latency, age at first exposure, calendar year of first exposure, and type of products were performed. The study confirmed that the vinyl chloride workers experience a significant mortality excesses in angiosarcoma (15 deaths), cancer of the liver and biliary tract (SMR = 641), and cancer of the brain and other central nervous system (SMR = 180). In addition, the study also found a significant mortality excess in emphysema/chronic obstructive pulmonary disease (COPD) (SMR = 179). On the other hand, the study did not find any excess in either respiratory cancer or lymphatic and hematopoietic cancer. This study also found an increase in biliary tract cancers, independent from liver cancer.
Solvent exposure and the risk of slips, trips, and falls among painters
Authors: Hunting Katherine L. , Matanoski Genevieve M. , Larson Marilyn , Wolford Rodney
Published: April 2007

This study evaluated risk factors for injurious and noninjurious slips, trips, and falls among painters and investigated the hypothesis that exposure to solvents influenced the risk of such accidents. The data were collected longitudinally over an 11 month period. Weekly self‐administered questionnaires detailed paint solvent exposure; work‐related slips, trips, and falls (STFs); and potentially hazardous job tasks and environmental conditions. An initial questionnaire ascertained personal data, such as age, solvent exposure history, and alcohol consumption. During the study, 2,088 person‐weeks of data were collected. Some participants provided many weeks of data, while others responded sporadically.

Exposure to potentially hazardous environmental conditions was significantly related to the occurrence of STFs during a week. Several measures of solvent exposure were evaluated for their effect on STFs. Low solvent exposure during a week significantly increased the occurrence of slips, trips, and falls compared to no exposure. Moderate and high weekly exposure were not associated with increased risk, however. Week‐to‐week variability in the amount of solvent exposure was a strong positive predictor of STFs. Further analysis showed that both increases and decreases in solvent exposure between the preceding 2 weeks and the week of the STF were positively related to the risk of such events. The stongest effect was observed for exposure increases over the preceding 2 weeks. Overall, the results suggest that solvent exposure variability may increase accident risk, and possible explanations are explored.
Occupational hearing loss in New York dairy farmers
Authors: Marvel Matthew E. , Pratt David S. , Marvel Laura H. , Regan Margaret , May John J.
Published: April 2007

A study of 49 randomly selected, full‐time dairy farmers was performed to assess the prevalence and nature of hearing loss in this population. An age‐ and sex‐matched group of rural, non‐farmers was also studied. Medical, occupational, and recreational histories were taken and standard audiometric testing was administered. Sixty‐five percent of farmers had hearing loss in the higher frequencies and 37% had losses in the mid‐frequency range as compared to 37% and 12% of non‐farmers respectively (p < .01). Farmers' left ears were more severely affected. The age of the subjects and the number of years spent farming were highly correlated with hearing loss. Correlation and regression analyses supported the hypothesis that the difference in the prevalence of hearing loss between the dairy farmers and the non‐farmers was due to occupational noise exposure on the farm.
From conjecture and refutation to the documentation of occupational diseases in Taiwan
Authors: Wang Jung‐Der
Published: April 2007

The documentation of occupational diseases in a developing country like Taiwan is a challenge to an occupational physician. For lack of a system including material safety data sheet (MSDS), workers are usually not aware of what chemicals they are exposed to. Since many occupational diseases have long latencies and do not show any specific symptoms and signs, recognition and identification of the occupational origin are often very difficult. Using databases which provide a relatively complete list of industrial chemicals and a set of specific signs and/or symptoms, combined with the epidemiologic approach of conjectures and refutations—i.e., considering and ruling out all possible alternative explanations—we have documented eight kinds of occupational diseases and an outbreak of botulism. We recommend that a similar approach be applied to any other country with a similar situation, and that a system involving an identification sheet (e.g., MSDS) for each chemical be advocated and implemented in such countries as one means to enable prompt recognition and prevention of occupational diseases.
A study of the effect of perchloroethylene exposure on semen quality in dry cleaning workers
Authors: Eskenazi Brenda , Wyrobek Andrew J. , Fenster Laura , Katz David F. , Sadler Marianne , Lee Jon , Hudes Mark , Rempel David M.
Published: April 2007

The purpose of this investigation was to determine the effects of perchloroethylene (PCE) exposure on human semen quality. We compared the semen quality of 34 dry cleaners with that of 48 laundry workers. We examined the relationships of 17 semen parameters to expired air levels of PCE and to an index of exposure based on job tasks in the last three months. The average sperm concentration was over 80 million for both dry cleaners and laundry workers, but approximately one‐quarter of each group was oligospermic. The overall percentage of abnormal forms was similar for the two groups; however, sperm of dry cleaners were significantly more likely to be round (t = −3.29, p = 0.002) and less likely to be narrow (t = 2.35, p = 0.02) than the sperm of laundry workers. These effects were dose‐related to expired air levels and to the exposure index after controlling for potential confounders (e.g., heat exposure). The average percent motile sperm for both groups was slightly over 60%; however, sperm of dry cleaners tended to swim with greater amplitude of lateral head displacement (ALH) than those of laundry workers (t = −1.73, p = 0.09), and level of PCE in expired air was a significant predictor of ALH in the multiple regression model (t = 2.00, p = 0.05). In addition, exposure index was a significant negative predictor of the sperm linearity parameter (t = −2.57, p = 0.01). These results suggest that occupational exposures to PCE can have subtle effects on sperm quality. Additional analyses are required to determine whether these effects are associated with changes in fertility.
A study of the effect of perchloroethylene exposure on the reproductive outcomes of wives of dry‐cleaning workers
Authors: Eskenazi Brenda , Fenster Laura , Hudes Mark , Wyrobek Andrew J. , Katz David F. , Gerson Jack , Rempel David M.
Published: April 2007

The purpose of this investigation was to compare the reproductive outcomes of wives of men exposed to perchloroethylene in the dry‐cleaning industry compared to those of wives of laundry workers. Seventeen female partners of dry cleaners and 32 partners of laundry workers were interviewed. The number of pregnancies and the standardized fertility ratios were similar between the two groups. Wives of dry cleaners did not have higher rates of spontaneous abortions. However, wives of dry cleaners were more than twice as likely to have a history of attempting to become pregnant for more than 12 months or to have sought care for an infertility problem. Cox proportional hazards models indicated that dry‐cleaners' wives had half of the per‐cycle pregnancy rate of wives of laundry workers, when controlling for other potential confounders (estimated rate ratio of 0.54, 95% C.I. = 0.23, 1.27).