bluuebunny/crossref_metadata_2025 huggingface dataset:
p130CASIs Required for Netrin Signaling and Commissural Axon Guidance
Authors: Liu Guofa , Li Weiquan , Gao Xue , Li Xiaoling , Jürgensen Claudia , Park Hwan-Tae , Shin Nah-Young , Yu Jian , He Ming-Liang , Hanks Steven K. , Wu Jane Y. , Guan Kun-Liang , Rao Yi
Published: January 2007

Netrins are an important family of axon guidance cues. Here, we report that netrin-1 induces tyrosine phosphorylation of p130CAS(Crk-associated substrate). Our biochemical studies indicate that p130CASis downstream of the Src family kinases and upstream of the small GTPase Rac1 and Cdc42. Inhibition of p130CASsignaling blocks both the neurite outgrowth-promoting activity and the axon attraction activity of netrin-1. p130CASRNA interference inhibits the attraction of commissural axons in the spinal cord by netrin-1 and causes defects in commissural axon projection in the embryo. These results demonstrate that p130CASis a key component in the netrin signal transduction pathway and plays an important role in guiding commissural axonsin vivo.
Long-Term Potentiation in the Visual Cortex Requires Both Nitric Oxide Receptor Guanylyl Cyclases
Authors: Haghikia Arash , Mergia Evanthia , Friebe Andreas , Eysel Ulf T. , Koesling Doris , Mittmann Thomas
Published: January 2007

The role of nitric oxide (NO)/cGMP signaling in long-term potentiation (LTP) has been a lingering matter of debate. Within the cascade, the NO receptor guanylyl cyclase (GC), the cGMP-forming enzyme that is stimulated by NO, plays a key role. Two isoforms of GC (α2-GC, α1-GC) exist. To evaluate their contribution to synaptic plasticity, we analyzed knock-out mice lacking either one of the GC isoforms. We found that LTP induced in the visual cortex is NO dependent in the wild-type mice, absent in either of the GC isoform-deficient mice, and restored with application of a cGMP analog in both strains. The requirement of both NO receptor GCs for LTP indicates the existence of two distinct NO/cGMP-mediated pathways, which have to work in concert for expression of LTP.
Learning-Induced Enduring Changes in Functional Connectivity among Prefrontal Cortical Neurons
Authors: Baeg Eun H. , Kim Yun B. , Kim Jieun , Ghim Jeong-Wook , Kim Jeansok J. , Jung Min W.
Published: January 2007

Current thinking about how memories are stored in the brain has been profoundly influenced by Donald O. Hebb's cell assembly hypothesis, which posits that (1) learning produces a stable alteration in patterns of connectivity among repeatedly coactivated neurons, and (2) memory retrieval involves reactivation of those altered patterns of connectivity. However, learning-induced changes in connectivity that persist over long periods of time have not been clearly demonstrated. In the present study, two spatial navigation tasks and a long-term ensemble recording technique are used to describe long-lasting modifications in functional connectivity (FC) (defined as changes in synchronous firing) of prefrontal cortical neurons in behaving rats. Animals were initially trained to alternate visiting two spatial locations on a figure-8-shaped maze to obtain a reward (alternating task 1). Afterward, while continuing on task 1, animals were additionally trained to visit only one spatial location on the same maze to obtain a reward (unilateral task 2). Multiple single units were recorded while rats were undergoing acquisition, retention, and performance of both tasks. Our data indicate that correlated firing of prefrontal cortical neurons changed significantly in early phases of training when learning rate was maximal but became progressively smaller in later phases when learning reached asymptote. After animals became proficient, FC remained constant, although neuronal activities varied across two different tasks. The present finding of negatively accelerated changes in FC confirms associative learning theories and provides crucial neurophysiological evidence for Hebb's hypothesis.
Yucatecans in Dallas, Texas: Breaching the Border, Bridging the Distance
Authors: DeRoche Constance P.
Published: January 2007

Yucatecans in Dallas, Texas: Breaching the Border, Bridging the Distance
. Rachel H. Adler. Boston: Pearson Allyn and Bacon, 2004, viii. 151 pp. 0–205–34089–7 http://www.ablongman.com
Representing Ancestor Worship as "Non-Religious": Hosoki Kazuko's Divination in the Post-Aum Era
Authors: Dorman Benjamin
Published: January 2007

Hosoki Kazuko, a popular fortune-teller, is one of the most prominent figures in the Japanese media, including television, books, and magazines. She is a prodigious author whose enormous sales of divination books (uranari hon) are the basis of her success. In some of these books, Hosoki discusses ancestor worship and associated rituals in connection with her form of divination, rokusei senjutsu (six-star astrology). Despite the widespread belief that such rituals have some connection to religion, Hosoki explicitly states that ancestor worship is "non-religious." I argue that Hosoki's representations draw on shared meanings about ancestor worship in combination with other Confucianbased notions in order to present her form of divination as common sense that should come naturally to all Japanese. Hosoki's statements can be viewed in the context of historical factors behind the idea many Japanese hold that they lack religious belief (mushûkyô) in addition to the deteriorating image of religion in general in the post-Aum era.
A Prototype Design of a Wireless Capsule Endoscope
Authors: Chan Y. , Meng M. Q.-H. , Wang X. , Wu J. C.-Y.
Published: January 2007

Diseases of the gastrointestinal tract, such as intestinal bleeding and ulceration, are very common. To determine the location of the disease, as well as to diagnose the problem, endoscopy is performed. A wireless capsule endoscope is a pill‐sized device that is easily swallowed by the patient. It is equipped with a camera and a wireless transmitter so that as it travels through the patient′s gastrointestinal tract, it takes pictures or video images of the tract and transmits the information out of the patient′s body. This article discusses the possible solutions and challenges of a wireless capsule endoscope in terms of the choice of wireless frequency and circuit components. A prototype is built with commercially available components to demonstrate the concept of the device.
Outcomes of Patients with Prostate Cancer Receiving Zoledronic Acid or Pamidronate for Prevention of Skeletal‐Related Events
Authors: Sherer Jeffrey T. , Adamus Andrea T.
Published: January 2007

Study Objective. To determine the relative effectiveness of two bisphosphonates—pamidronate and zoledronic acid—for preventing skeletal‐related events (SREs) in patients with prostate cancer metastatic to bone.

Design. Retrospective cohort study.

Setting. Large, tertiary care cancer center.

Patients. One hundred thirty‐seven patients with a diagnosis of prostate cancer who received either pamidronate or zoledronic acid between January 1, 1998, and December 31, 2004, were identified in the electronic medical records; 24 of these patients met all prespecified eligibility criteria, and 105 patients met relaxed eligibility criteria.

Measurements and Main Results. Using a binary logistic regression model, we explored the effect of the bisphosphonate received on development of an SRE. Whether the patient was receiving chemotherapy as of the date of first receipt of a study drug, the number of bisphosphonate doses received, time since the diagnosis of prostate cancer, and the number of previous SREs were included as covariates. The odds ratio for developing an SRE after receiving zoledronic acid was 0.80 (95% confidence interval 0.08–7.50) compared with the reference group that received pamidronate. This difference did not reach statistical significance (p=0.84). Because of the limited number of patients who met all prespecified eligibility criteria, various post hoc analyses were performed in the 105 patients with use of relaxed eligibility criteria. None provided definitive evidence of the superiority of one agent versus the other.

Conclusion. No definitive evidence of a difference in the efficacy for preventing the development of an SRE was found between pamidronate and zoledronic acid, although a smaller‐than‐expected sample size impairs the interpretability of this finding. In the absence of additional research, it seems reasonable to assume that no clinically important difference exists between the two agents.
Emerging Options for Treatment of Invasive, Multidrug‐Resistant Staphylococcus aureus Infections
Authors: Drew Richard H.
Published: January 2007

Limited established treatment options exist for the treatment of serious, invasive infections caused by multidrug‐resistant Staphylococcus aureus, most notably nosocomially acquired methicillin‐resistant S. aureus (MRSA). Although vancomycin represents the gold standard for therapy of such invasive infections, reports of increasing in vitro resistance to vancomycin, combined with reports of clinical failures (with this and other antistaphylococcal agents), underscore the need for alternative therapies. Older agents with favorable in vitro activity available in both oral and intravenous dose forms include trimethoprim‐sulfamethoxazole and clindamycin. Limited clinical data exist to support their routine use as initial therapy in the treatment of invasive disease. However, these and other options (e.g., tetracyclines) are being reexplored in the setting of increasing concern over MRSA acquired in the community setting. Newer treatment options for MRSA include linezolid, quinupristin‐dalfopristin, daptomycin, and tigecycline. With the exception of linezolid, these newer agents require intravenous administration. Combination therapy may be considered in select invasive diseases refractory to standard monotherapies. These diseases include infections such as endocarditis, meningitis, and prosthetic device infections. Additional alternatives to vancomycin are under clinical investigation. Those in later stages of development include oritavancin, dalbavancin, telavancin, and ceftobiprole.
Mechanical Ventilation: A Tutorial for Pharmacists
Authors: Cawley Michael J.
Published: January 2007

Mechanical ventilation is an integral part of the critical care environment and requires orchestration by a multidisciplinary team of clinicians to optimize therapeutic outcomes. By tradition, pharmacists have not been included on this team since this therapeutic modality is not considered relevant to their scope of practice. However, pharmacists play a critical role in the management of patients receiving mechanical ventilation by assisting in the development of institutional guidelines and protocols, by maintaining accuracy of prescribed drug dosages, by monitoring for drug‐drug and drug‐disease interactions, by assisting with alternative drug selections, and by maintaining continued quality assessment of drug administration. Pharmacists able to understand and integrate mechanical ventilation with the pharmacotherapeutic needs of patients are better qualified practitioners. The goal of this article is to help clinical pharmacists better understand the complexities of mechanical ventilation and to apply this information in optimizing delivery of pharmaceutical agents to critical care patients.
Tenecteplase for Malignant Pericardial Effusion
Authors: Johnson Kelly K. , Soundarraj Dwarakraj , Patel Parag
Published: January 2007

Pericardial effusions may necessitate placement of a catheter into the pericardial space for continuous drainage. If the effusion material is fibrinous or loculated, drainage may slow or cease over time, allowing reaccumulation. Limited data exist to guide the selection of a fibrinolytic agent and the most appropriate dose. We report the case of a 79‐year‐old woman with malignant pericardial effusion who responded to intrapericardial administration of tenecteplase to facilitate drainage. The patient received three doses of tenecteplase—15 mg, 7.5 mg, and 7.5 mg—over 3 days, resulting in significant drainage. No adverse effects were noted except for a transient episode of hemodynamically stable atrial fibrillation. Use of fibrinolytic agents to facilitate pericardial drainage may offset the need to repeatedly replace the catheter if flow subsides despite continued presence of fluid in the pericardial space.
Zolpidem Addiction in a Pregnant Woman with a History of Second‐Trimester Bleeding
Authors: Askew Jennifer P.
Published: January 2007

Whether zolpidem crosses the placenta in humans is unknown. A 30‐year‐old Caucasian woman with a history of zolpidem abuse underwent spontaneous vaginal delivery at 38 weeks' gestation. Total fetal exposure to zolpidem was unknown, but it was estimated to be at least 1000 mg over at least 1 month. Typical peak plasma concentrations after a single 5‐ and 10‐mg dose of zolpidem are 29–113 ng/ml (mean 59 ng/ml) and 58–272 ng/ml (mean 121 ng/ml), respectively. Cord blood was sampled for zolpidem, with a result of 41 ng/ml. Despite the presence of zolpidem in the cord blood sample, the neonate was active and alert after normal delivery. No withdrawal symptoms were noted, and the mother and neonate were discharged home after 48‐hour observation. This case report indicates that zolpidem crosses the human placenta, as was exemplified with cord blood sampling. The drug should therefore be used during pregnancy only if clearly necessary.
Myopathy Associated with Atorvastatin‐Ezetimibe Combination Therapy
Authors: Weffald Linda A. , Flach Lynn A.
Published: January 2007

The 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase inhibitors (statins) play a prominent role in the treatment of dyslipidemia. Overall, statins are well tolerated, with a low occurrence of adverse effects. More serious reactions to statins have been reported, although they are rare (e.g., rhabdomyolysis 0.3–13.5 cases/million statin prescriptions). Combination therapy to treat dyslipidemia has become common in many patients; however, it can also increase the risk of serious adverse effects. We report the case of a patient who experienced muscle pain and elevated creatine kinase levels 16 days after the addition of ezetimibe to his atorvastatin therapy for hypercholesterolemia. Twelve days after stopping the ezetimibe, his muscle pain resolved and his serum creatine kinase level returned to baseline. This case report raises questions regarding the safety of high‐dose atorvastatin and ezetimibe combination therapy and suggests that caution and careful monitoring may be warranted.
Axisymmetric numerical modeling of a unit cell in geosynthetic-reinforced, column-supported embankments
Authors: Smith M. , Filz G.
Published: January 2007

Rational design of geosynthetic-reinforced, column-supported embankments requires realistic estimates of the portion of the embankment load that acts vertically downward on the geosynthetic in the area underlain by the foundation soil located between columns. This vertical load can then be used to calculate the strain and tension that develops in the plane of the geosynthetic reinforcement. Several simplified methods are available for calculating the vertical load acting on the geosynthetic, but these methods produce dramatically different results, and there is not agreement regarding which method produces the best estimates. Axisymmetric numerical modeling provides an alternative approach for determining the vertical stresses that develop in the embankment and act on the geosynthetic reinforcement. In this research, axisymmetric numerical modeling is verified against: (1) instrumentation data from a full-scale column-supported test embankment, albeit without geosynthetic reinforcement, at the I-95/Route 1 Interchange project in Virginia, USA; (2) an analytic solution for a disk of membrane material that is pinned at its outer edge and subject to a vertical stress; (3) instrumentation data from a pilot-scale test of a geosynthetic-reinforced, column-supported embankment conducted at the University of Kassel in Germany; and (4) three-dimensional numerical analyses. The results demonstrate that drained axisymmetric numerical analyses using a mesh of linear elastic zones to represent the geosynthetic reinforcement produce results in good agreement with instrumentation data, the analytic solution, and three-dimensional analyses.
Developing Real Alternatives to Medical Models
Authors: Boyle Mary
Published: January 2007

Many challenges to medical models of emotional distress are all too easily assimilated into a medical model and thus lose part of their power. This article suggests some necessary characteristics of challenges that would be much less easy to assimilate, and illustrates these in detail through an analysis of auditory hallucinations or voice hearing.
Mental Health Screening in Schools: Essentials of Informed Consent
Authors: Jackson Grace E.
Published: January 2007

Increasing numbers of public schools are adopting the use of mental health screening programs for the purpose of identifying suicidality or psychiatric conditions in children and teens. Concerned observers maintain that these programs commonly violate the requirements of federal law, because they fail to provide properly informed consent for evaluation and special services. This article presents a critical analysis of the requirements of informed consent in education, discusses the problems of consensus, and offers basic facts that might be communicated by pertinent authorities in order to facilitate state compliance with the Individuals with Disabilities Education Act (IDEA).
Can Biological and Psychological Intervention Be Integrated Into the Treatment of Psychosis? Probably Not
Authors: Karon Bertram P.
Published: January 2007

Clinical experience leads to the conclusion that schizophrenics and other psychotics can best be treated by psychoanalytic therapy without medication. So do research studies using competent therapists and control groups, such as Deikman and Whitaker (1979) and Karon and VandenBos (1981). The supposed necessity for biological treatments is based on the lack of appropriate psychotherapeutic training and the belief that medications are extremely effective. But current medications seem to interfere with full recovery. Medication can sometimes be used as a temporary adjunct, but should be withdrawn as quickly as the patients can tolerate. In the end, all we have to offer is understanding, but that is a great deal.
Upscaling Hydraulic Properties and Soil Water Flow Processes in Heterogeneous Soils: A Review
Authors: Vereecken H. , Kasteel R. , Vanderborght J. , Harter T.
Published: January 2007

This review covers, in a comprehensive manner, the approaches available in the literature to upscale soil water processes and hydraulic parameters in the vadose zone. We distinguish two categories of upscaling methods: forward approaches requiring information about the spatial distribution of hydraulic parameters at a small scale, and inverse modeling approaches requiring information about the spatial and temporal variation of state variables at various scales, including so‐called “soft data”. Geostatistical and scaling approaches are crucial to upscale soil water processes and to derive large‐scale effective fluxes and parameters from small‐scale information. Upscaling approaches include stochastic perturbation methods, the scaleway approach, the stream‐tube approach, the aggregation concept, inverse modeling approaches, and data fusion. With all upscaling methods, the estimated effective parameters depend not only on the properties of the heterogeneous flow field but also on boundary conditions. The use of the Richards equation at the field and watershed scale is based more on pragmatism than on a sound physical basis. There are practically no data sets presently available that provide sufficient information to extensively validate existing upscaling approaches. Use of numerical case studies has therefore been most common. More recently and still under development, hydrogeophysical methods combined with ground‐based remote sensing techniques promise significant contributions toward providing high‐quality data sets. Finally, most of the upscaling literature in vadose zone research has dealt with bare soils or deep vadose zones. There is a need to develop upscaling methods for real world soils, considering root water uptake mechanisms and other soil–plant–atmosphere interactions.
Groundwater Nitrate Spatial and Temporal Patterns and Correlations: Influence of Natural Controls and Nitrogen Management
Authors: Hong Nan , White Jeffrey G. , Weisz Randy , Gumpertz Marcia L. , Duffera Miressa G. , Cassel D. Keith
Published: January 2007

To use shallow groundwater NO3–N concentration as an indicator of groundwater quality requires understanding its patterns, correlations, and controls across space and time. Within a study comparing variable‐rate and uniform N management, our objectives were to determine groundwater NO3–N patterns and correlations at various spatial and temporal scales and their association with natural controls and N management. Experiments in a random, complete block design were conducted in a 2‐yr crop rotation in North Carolina that included one variable‐rate and two uniform N management treatments to wheat (Triticum aestivumL.) and corn (Zea maysL.). We measured groundwater NO3–N and depth every 2 wk at 60 well nests, sampling the 0.9‐ to 3.7‐m depth. Field‐mean NO3–N varied with time from 5.5 to 15.3 mg NO3–N L−1These variations were correlated primarily with concurrent changes in water table elevation and depth. Mean NO3–N exhibited two preferred states: high when the water table was shallow and low when the water table was deep. Temporal NO3–N fluctuations greatly exceeded treatment effects. Treatments appeared to affect NO3–N temporal covariance structure. Groundwater NO3–N spatial patterns and correlations were associated mostly with saturated hydraulic conductivity and water table fluctuations and appeared influenced by subsurface lateral flow. When treatment effects became consistently significant later in the study, they overrode natural controls, and NO3–N was spatially uncorrelated or exhibited shorter spatial correlation ranges and patterns associated predominantly with treatments.
The Shape of the Transpiration Reduction Function under Plant Water Stress
Authors: Metselaar Klaas , de Jong van Lier Quirijn
Published: January 2007

Assuming transpiration to be reduced after a critical pressure head (usually chosen as −1.5 MPa or −150 m) at the root surface has been reached, transpiration rates in this so‐called falling‐rate phase were analyzed numerically for soils described by the van Genuchten–Mualem equations (numerical soils). The analysis was based on the differential equation describing radial flow to a single root. Numerically, the system was simulated by an implicit scheme. It is shown that, at limiting hydraulic conditions, relative transpiration (ratio between actual and potential transpiration) is equal to relative matric flux potential (ratio between actual matric flux potential and matric flux potential at the onset of limiting hydraulic conditions). Given this equality, transpiration reduction functions as a function of soil water content and as a function of time are presented for five types of analytical soils: a constant diffusivity, Green and Ampt, Brooks and Corey, versatile nonlinear, and exponential soil. While in the case of constant diffusivity, relative transpiration decreases as a linear function of water content, for the remaining four cases the decrease is a concave function of soil water content. Numerical simulations also result in a concave shape, unless the difference between water content at the onset of limiting hydraulic conditions and at permanent wilting is very small, for example, at high root densities. These discrepancies may be explained by the relative importance of a transition period between the constant‐ and falling‐rate phases.
Uranium Immobilization by Hydrogen Sulfide Gaseous Treatment under Vadose Zone Conditions
Authors: Zhong Lirong , Thornton Edward C. , Deng Baolin
Published: January 2007

Mobility of hexavalent uranium [U(VI)] in H2S‐treated soils was investigated using laboratory column experiments to assess the potential of applying in situ gaseous reduction for U immobilization in the vadose zone. Soil from the Hanford Formation in the U.S. Department of Energy Hanford Site, Washington, was used in this study. The impact of water chemistry and soil treatment on U(VI) immobilization and the role of gas humidity on soil treatment were investigated. The study revealed that soil uptake of U(VI) from deionized water was much higher than that from the simulated Hanford groundwater. Nevertheless, gas‐treated soil was still shown to have the potential for immobilizing U(VI) from the simulated groundwater. In addition, changes in H2S column breakthrough indicated that humidity enhanced the reduction of soil Fe. In the first 20 pore volumes, the soil treated with moisturized H2S gas can effectively immobilize >80% of the mobile U(VI). Primary mechanisms for U immobilization included U(VI) sorption to the sediments, reduction of U(VI) to insoluble U(IV), and enhanced adsorption of U(VI) to newly formed Fe oxides. Remobilization of U following reoxidation of the sediment was relatively insignificant under the experimental conditions applied, apparently owing to the enhanced adsorption of U to poorly crystallized hydrous ferric oxide products.
Vertical Spatial Sensitivity and Exploration Depth of Low‐Induction‐Number Electromagnetic‐Induction Instruments
Authors: Callegary James B. , Ferré Ty P. A. , Groom R. W.
Published: January 2007

Vertical spatial sensitivity and effective depth of exploration (de) of low‐induction‐number (LIN) instruments over a layered soil were evaluated using a complete numerical solution to Maxwell's equations. Previous studies using approximate mathematical solutions predicted a vertical spatial sensitivity for instruments operating under LIN conditions that, for a given transmitter–receiver coil separation (s), coil orientation, and transmitter frequency, should depend solely on depth below the land surface. When not operating under LIN conditions, vertical spatial sensitivity and de also depend on apparent soil electrical conductivity (σa) and therefore the induction number (β). In this new evaluation, we determined the range of σa and β values for which the LIN conditions hold and how de changes when they do not. Two‐layer soil models were simulated with both horizontal (HCP) and vertical (VCP) coplanar coil orientations. Soil layers were given electrical conductivity values ranging from 0.1 to 200 mS m−1 As expected, de decreased as σa increased. Only the least electrically conductive soil produced the de expected when operating under LIN conditions. For the VCP orientation, this was 1.6s, decreasing to 0.8s in the most electrically conductive soil. For the HCP orientation, de decreased from 0.76s to 0.51s Differences between this and previous studies are attributed to inadequate representation of skin‐depth effect and scattering at interfaces between layers. When using LIN instruments to identify depth to water tables, interfaces between soil layers, and variations in salt or moisture content, it is important to consider the dependence of de on σa
Transport characteristics of surface-modified nanoscale zero-valent iron in porous media
Authors: Kanel S.R. , Choi H.
Published: January 2007

Highly efficient, versatile, adsorbent, nanoscale zero-valent iron (NZVI) was synthesised and encapsulated by an anionic polymer to make it a mobile delivery vehicle (DV-NZVI) for in-situ groundwater and soil remediation. NZVI was found to be highly dispersed with surfactant within a size of 1–100 nm. Laboratory column experiments were conducted by employing glass beads as a porous medium to delineate the characteristics of DV-NZVI transport as a reactive material in saturated zones under a number of conditions. It was observed that there was an optimum concentration of polymer, i.e. 6 g/L, for maximum transport of DV-NZVI, at which point, as the flow rate increases, the transport of DV-NZVI increases. Similarly, at the optimum concentration we observed that as the depth of porous media increased, the breakthrough of DV-NZVI was retarded. These results confirmed that DV-NZVI has significant potential for use as a colloidal reactive barrier material in deep groundwater systems in lieu of pump and treat approaches and conventional permeable reactive barriers (PRB).
Groundwater recharge in an endoreic basin with reclaimed municipal wastewater
Authors: De Feo G. , Galasso M. , Belgiorno V.
Published: January 2007

The aim of this paper was to evaluate the groundwater pollution in an endoreic basin in southern Italy. The aquifer circulation was carried out on two different levels: a shallow groundwater, with a water table of about 10 m, and a deep groundwater in a karst aquifer, with a water table of 140–190 m. Reclaimed municipal wastewater and superficial water collected in the catchment area were both drained in a swallow hole linked with the deep groundwater. The agricultural practice conducted in the endoreic basin produced an excess of nitrate in the soil. Nitrate was subsequently washed out and displaced in the groundwater. With regard to the EU Drinking Water Directive (98/83/EC), the research activity conducted during 2003 showed the absence of pollution in the deep groundwater used for drinking water supply. The shallow groundwater, instead, was strongly influenced by agricultural and pasture activities, with detectable levels of nitrates and bacteria. In order to reduce the load of pollution entering the swallow hole and then in the deep groundwater, the realisation of a constructed wetland plant was proposed to improve the quality of reclaimed wastewater, as well as to pursue the wastewater reuse in agriculture.
The role of biofilms in water reclamation and reuse
Authors: Bishop P.L.
Published: January 2007

Biofilms play a major role in many water reclamation and reuse technologies. Normally, wherever there is water, a support surface and nutrients available, a biofilm will form. In some cases, this may result in problems for the water treatment system, due to biofouling or the growth of pathogenic or other unwanted microbes, but more frequently, the biofilm serves a very useful purpose by biodegrading organic contaminants in the water or by converting unwanted inorganic materials into harmless ones. Biofilms are commonly found associated with membrane reactors and filtration systems used in water reclamation and reuse systems, and are often a critical component. They are also found in soils where they may impact water injection or removal systems, or in situ bioremediation. Knowledge of the way biofilms form, how they grow and how to control them is critical for effective design and operation of many water reclamation facilities. This paper explores the modes of formation and growth of biofilms, modern methods for exploring the structure and function of biofilms, and how to control their growth. This paper also presents details on our development of microelectrode sensor arrays for continuous soil pore water quality monitoring.
Continuous removal of hydrogen peroxide with immobilised catalase for wastewater reuse
Authors: Yoon D.S. , Won K. , Kim Y.H. , Song B.K. , Kim S.J. , Moon S.-J. , Kim B.S.
Published: January 2007

Hydrogen peroxide was continuously removed for wastewater reuse using an immobilised biocatalyst. A commercial catalase, which is an enzyme to decompose hydrogen peroxide to water and oxygen, was entrapped in chitosan beads. Hydrogen peroxide in aqueous solutions of varying pH, temperature and concentration was continuously removed through a reactor containing the catalase-entrapped chitosan beads at high efficiency for 24 h. Additional silicate coating of the chitosan beads resulted in significant improvements in the catalase performance under harsh conditions, which are often found in peroxide-based industrial processes. We expect that immobilisation of catalases can enhance their applicability for continuous degradation of hydrogen peroxide for wastewater reuse.
Water management in Windhoek, Namibia
Authors: Lahnsteiner J. , Lempert G.
Published: January 2007

For decades, the city of Windhoek in Namibia succeeded in stretching their limited potable water resources through strict water management, latterly including wastewater reclamation and direct potable reuse. An integrated approach was followed and proper policies were put in place. This was followed up with appropriate legislation, education, policing and technical and financial measures with the result that extreme water shortages were overcome even in times of severe droughts.
Calculating nitrogen-removal efficiency with a one-dimensional nitrogen budget model of a reed-wetland soil system
Authors: Yutani K. , Tanaka N.
Published: January 2007

A simple one-dimensional model that can evaluate the transport and fate of nitrogen in wetland soil-vegetation systems was developed to calculate the nitrogen-removal efficiencies of reed-bed wetlands. A common wetland plant, Phragmites australis, was the focus of this study. Seasonal variations of temperature, seasonal changes of nitrogen uptake by vegetation, the vertical distribution of root biomasses and oxygen transport into the soil by vegetation were considered in the model. Field observations were conducted to determine some model parameters and to validate the model, although most of the parameters were adopted from data published in Europe and North America. Field observations were carried out at the Minuma-Tanbo wetland (35°52′N, 139°43′E) in Japan. The calculated concentrations of NH4-N in the soils were about 10 times larger than those of the observational results. On the other hand, calculated NO3-N concentrations were about half of the observational data. However, the calculated nitrogen-removal efficiencies indicated the same trends as previous studies. It was found that the hydraulic loading rate played a key role in relation to nitrogen removal and nitrogen transformation in reed wetland systems.
Removal of As(V) and As(III) from water with a PEI-modified fungal biomass
Authors: Deng S. , Ting Y.P.
Published: January 2007

A novel biosorbent was prepared by chemically grafting polyethylenimine (PEI) on the fungal biomass of Penicillium chrysogenum through a two-step reaction. The PEI-modified biomass was found to possess zero zeta potential at pH 10.4. Owing to the protonation of amine groups on the biosorbent surface, the biosorbent is favourable for the removal of anionic arsenic species in water. The sorption capacity for As(V) at pH 3 increased by 5.7-fold after surface modification. The sorption performances including kinetics and isotherm were investigated and several models were used to describe the experimental data. The pseudo-second-order model described the kinetic data better, while the Langmuir equation was the better model to fit the isotherm data. The corresponding thermodynamic parameters for As(V) and As(III) sorption were also calculated.
An experimental study for chlorine residual and trihalomethane formation with rechlorination
Authors: Lee J. , Lee D. , Sohn J.
Published: January 2007

Maintenance of adequate chlorine residuals and control of disinfection byproducts (DBPs) throughout water distribution systems is currently an important issue. In particular, rechlorination can be a powerful tool in controlling adequate chlorine residual in a large distribution system. The patterns of chlorine decay and formation of DBPs due to rechlorination are different from those of chlorination; chlorine decay is slower and trihalomethane (THM) formation is lower with rechlorination. The present study evaluates whether existing predictive models for chlorine residual and THM formation are applicable in the case of rechlorination. A parallel first-order decay model represents the best simulation results for chlorine decay, and an empirical power function model (modified Amy model) with an introduced correction coefficient (ϕ1, ϕ2) is more suitable to THM formation.
The beneficial effects of storage on the quality of wastewater for irrigation: a case study in Sicily
Authors: Mancini G. , Barone C. , Roccaro P. , Vagliasindi F.G.A.
Published: January 2007

Although the main function of reservoirs in agriculture is to allow the storage and temporal shifting of large volumes of waters, further benefits emerge from their application in wastewater reuse systems. In fact, as observed in several other studies carried out on such complex natural systems, the storage period, under proper conditions, can lead to a significant improvement of the water quality for irrigation thanks to concurrent physical, chemical and biological processes. In order to investigate the reservoir dynamics, an experimental research was carried out in a farm reservoir (volume of 11,000 m3, maximum depth of 6.3 m and mean depth of about 5 m), receiving treated wastewater and subject to scheduled highly variable input to volume ratios, in order to observe the broadest range of behaviour responses. Specifically, over a monitoring period lasted 4 months, the reservoir was operated as a standard batch reactor in the first and third phases and as a continuous flow reactor in the second one. Based on correlation analysis between the chemical, physical and biological water parameters and operational ones, a new operative index is proposed which integrates the morphological characteristics of the tank and the management ones, and shows a significant correlation with the qualitative characteristics of the stored water.
On-site sanitation: a viable alternative to modern wastewater treatment plants
Authors: Lamichhane K.M.
Published: January 2007

Rapid population growth and urbanization are exerting excessive pressure on soil and water resources. To address these problems this paper proposes a cheap and sustainable alternative sanitation system, which accelerates nutrient recycling (“closing the loop”): ecological sanitation (ecosan) is a potential alternative to conventional sanitation systems that replenishes the organic matter and nutrients of the soil that are taken off as the crop harvest. A comparison is made of the environmental and the operation and maintenance costs between a modern wastewater treatment plant and on-site sanitation. An elevated double box urine diverting toilet (“ecotoilet”) is proposed and its advantages and disadvantages over a system with a centrally controlled modern WWTP are discussed. Bagmati Area Sewerage Project in Kathmandu is taken as an example of modern WWTP and ecosan being practiced in a village in Nepal is taken as an example of ecotoilet for the comparison.
Helminth ova removal from wastewater for agriculture and aquaculture reuse
Authors: Jimenez B.
Published: January 2007

In the new version of the World Health Organization (WHO), water reuse guidelines helminth ova are considered one of the main target pollutants to be removed from wastewater reuse for agriculture and aquaculture purposes. In spite of this, along with the fact that helminth ova have been considered the main health risk to wastewater reuse for agriculture for at least 20 years, relatively little research has been done to control helminth ova in the wastewater treatment field. This paper addresses (1) characteristics of helminth ova and differences with microorganisms; (2) the most frequent helminth ova genus found in wastewater; (3) helminth ova content in developed and developing countries wastewater; (4) reasons why conventional disinfection methods cannot be applied; (5) main removal mechanisms; and (6) processes that in practice have effectively removed or inactivated helminth ova.
Assessment of the risk of infection by Cryptosporidium and Giardia in non-potable reclaimed water
Authors: Ryu H. , Alum A. , Mena K.D. , Abbaszadegan M.
Published: January 2007

Quantitative risk assessment for Cryptosporidium oocysts and Giardia cysts was performed to determine the public health significance of non-potable use of tertiary treated reclaimed water. Seven reclaimed water treatment plants in the southwestern United States participated in this study. The average public exposure to oocysts and cysts was estimated, based on concentrations, recovery efficiency, viability and three exposure scenarios. The exponential dose-response model was chosen to determine the probability of infection from ingestion of various numbers of oocysts and cysts. The risks of infection for Giardia were approximately one or two orders of magnitude higher than those for Cryptosporidium. The combined risks of infection from oocysts and cysts at sites using a combination of chlorination and UV disinfection would meet the annual acceptable risk of 1.00E-04, whereas those at the other utilities using only chlorination indicated higher probability of infection than the 1.00E-04 resulting from accidental consumption of a small amount of non-potable reclaimed water.
Fungal biodegradation of carbofuran and carbofuran phenol by the fungus Mucor ramannianus: identification of metabolites
Authors: Seo Jiyoung , Jeon Junho , Kim Sang-Don , Kang Suil , Han Jaehong , Hur Hor-Gil
Published: January 2007

The fungus Mucor ramannianus was tested to elucidate the biological fate of a class of N-methyl carbamate pesticide carbofuran and its hydrolysed form carbofuran phenol. The elution profile obtained from analysis by high-pressure liquid chromatography equipped with a reverse-phase C-18 column showed that two peaks occurred after incubation of M. ramannianus with which 1 mM carbofuran was combined as a final concentration. In culture of M. ramannianus with 1 mM carbofuran phenol, it produced two other metabolites compared to metabolites of carbofuran. LC/MS analysis suggested that two of the metabolites produced from carbofuran phenol were most likely to be 2-hydoxy-3-(3-methylpropan-2-ol)phenol or 7a-(hydroxymethyl)-2,2-dimethylhexahydro-6H-furo[2,3-b]pyran-6-one and 3-hydroxycarbofuran-7-phenol.
Colloidal silica removal in coagulation processes for wastewater reuse in a high-tech industrial park
Authors: Chuang S.H. , Chang T.C. , Ouyang C.F. , Leu J.M.
Published: January 2007

Four experiments of coagulation and flocculation were conducted to investigate the characteristics of colloidal silica removal in a high-tech industrial wastewater treatment plant for reclamation and reuse of the effluent. Experimental results illustrated that poly-aluminium chloride (PACl) showed higher performances on colloidal silica removal than alum. Interestingly, the two coagulants demonstrated the same capacity on silica removal. The specific silica removal capacity was approximately 0.135 mg SiO2/mg Al2O3 when the dosage of coagulants was in the range 30–150 mg/L Al2O3. In addition, the silica was reduced significantly at the condition of pH above 8. Experimental data implied that precipitation of aluminium flocs was the major mechanism for colloid silica removal in PACl and alum coagulation, besides, charge adsorption was also important for improving removal efficiency. Moreover, the addition of polyacrylic acid (PAA) as a flocculant could slightly advance silica removal in the PACl coagulation. The combined PACl/PAA/flocs coagulation was effective for the removal of colloidal silica, soluble COD, and turbidity and also suitable as a pretreatment unit in wastewater reclamation and reuse processes.
Development of sequencing batch reactor with step feed and recycle
Authors: Lee Y.W. , Kim Y.J. , Chang N.I. , Lee J.G. , Lee B.H.
Published: January 2007

SBR process shows high nitrogen and phosphorus removal in countries where separated sewers are used. On the other hand, removal efficiency is low in countries where combined sewers are used though the same SBR is applied. This is because the organic concentration (as BOD), which is used as carbon source for denitrification, of combined sewers is much lower than that of separated sewers. Almost all sewers in Korea are combined, and their BOD is low by about 1/2 over the level needed for denitrification. In this study, a SBR process that can optimise organic usage by step feed and recycle is thus developed to increase the removal efficiency of nitrogen and phosphorus, and the results show that the removal rates of BOD, T-N and T-P are 95.4, 81.4 and 86.1%, respectively, though influent BOD is low.
Size and fractal dimension of particles in the River Nakdong
Authors: Moon B.-H. , Seo G.-T. , Jang D.-J. , Kim S.-S.
Published: January 2007

Water samples were collected at seven sites located along the River Nakdong on 30 occasions. Water quality, size and the fractal dimension (dF) of suspended particles were measured. The laser light scattering method was used to obtain the size and dF of suspended particles. The average size of particles in this river ranged from 89 μm and 169 μm, which appears to be relatively coarse compared with other rivers worldwide. The average dF of suspended particles in this study ranged from 1.8 to 1.9. Slight variations in fractal dimension values and other particle characteristics results from various measuring methods available. The correlation analysis showed that DO, TN, NO3 and chlorophyll-a had significant positive relationships with particles size, whereas flow rates and temperature had negative relationships. However, the factors which had positive relationships with particles size showed negative relationships with the dF of suspended particles. Generally, as the size of particles increased, the fractal dimension of particles decreased which indicated that the shape of the larger particles became more irregular relative to that of the smaller ones. To obtain and apply the statistical functional relationship between water quality characteristics, multiple linear regression equations of the size and fractal dimension of particles on explanatory variables such as pH, BOD, TSS, DO, T-N and T-P have been established.
Mechanistic evidence and efficiency of the Cr(VI) reduction in water by different sources of zerovalent irons
Authors: Yang J.E. , Kim J.S. , Ok Y.S. , Yoo K.R.
Published: January 2007

The objective of this research was to assess the mechanism and effectiveness of the zerovalent iron (ZVI) to remediate the Cr(VI) contaminated water. The mechanism of Cr(VI) reduction by ZVI was evaluated by characterising surface properties and chemical compositions of Fe and Cr products using SEM-EDS, XRD and XPS analyses. The effectiveness of ZVI in Cr(VI) reduction was assessed by the luminescent bacteria (Photobacterium Phosphoreum). The Cr(VI) was reduced to Cr(III), when the reactive Fe0 was oxidised to Fe(II,III), showing the presence of Fe2O3, (Fe-Cr)2O3 and FeOOH. The SEM-EDS analysis showed that ZVI with a higher reducing capacity was more subject to changes of surface and morphological properties due to ionisation of ZVI. The Cr and Fe in precipitates subsisted exclusively in the Cr(III) or Fe(III) states with the respective forms of Cr(OH)3 or Cr2O3 and FeOOH or Fe2O3. Electrons produced from ZVI oxidation reduced Cr(VI) to Cr(III), thus resultantly Cr(III) precipitated or co-precipitated with Fe(III) to form Fe(III)-Cr(III) hydroxide or Fe(III)-Cr(III) oxyhydroxide. Toxicity of water reacted with ZVI was significantly lower than that of the untreated water.
Anaerobic Treatment of High‐Saline Wastewater Using Halophilic Methanogens in Laboratory‐Scale Anaerobic Filters
Authors: Riffat R. , Krongthamchat K.
Published: January 2007

The presence of a high concentration of sodium in wastewater is considered inhibitory for anaerobic biological treatment. This research was designed to investigate the potential use of halophilic methanogens and a mixed culture of halophilic methanogens and digester sludge, in anaerobic filters, for treatment of organic pollutants in high‐saline wastewater at 35°C. Data related to startup of the filters are presented. Both halophilic and mixed‐culture anaerobic filters were able to operate at a sodium chloride concentration of 35 g/L, at organic loading rates (OLRs) of 6.2 and 5 kg chemical oxygen demand (COD)/m 3 · d, respectively. The COD removal efficiency was as high as 80%, and the systems were able to maintain a low volatile fatty acids concentration of 500 mg/L. No significant difference in COD removal was observed between the halophilic filter and the mixed‐culture filter. Increasing the salt concentration to 37 g/L at an OLR of 3 kg/m 3 · d caused system failure.