bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility and validity of International Classification of Diseases based case mix indices
Authors: Yang Che-Ming , Reinke William
Published: October 2006

Background

Severity of illness is an omnipresent confounder in health services research. Resource consumption can be applied as a proxy of severity. The most commonly cited hospital resource consumption measure is the case mix index (CMI) and the best-known illustration of the CMI is the Diagnosis Related Group (DRG) CMI used by Medicare in the U.S. For countries that do not have DRG type CMIs, the adjustment for severity has been troublesome for either reimbursement or research purposes. The research objective of this study is to ascertain the construct validity of CMIs derived from International Classification of Diseases (ICD) in comparison with DRG CMI.

Methods

The study population included 551 acute care hospitals in Taiwan and 2,462,006 inpatient reimbursement claims. The 18thversion of GROUPER, the Medicare DRG classification software, was applied to Taiwan's 1998 National Health Insurance (NHI) inpatient claim data to derive the Medicare DRG CMI. The same weighting principles were then applied to determine the ICD principal diagnoses and procedures based costliness and length of stay (LOS) CMIs. Further analyses were conducted based on stratifications according to teaching status, accreditation levels, and ownership categories.

Results

The best ICD-based substitute for the DRG costliness CMI (DRGCMI) is the ICD principal diagnosis costliness CMI (ICDCMI-DC) in general and in most categories with Spearman's correlation coefficients ranging from 0.938-0.462. The highest correlation appeared in the non-profit sector. ICD procedure costliness CMI (ICDCMI-PC) outperformed ICDCMI-DC only at the medical center level, which consists of tertiary care hospitals and is more procedure intensive.

Conclusion

The results of our study indicate that an ICD-based CMI can quite fairly approximate the DRGCMI, especially ICDCMI-DC. Therefore, substituting ICDs for DRGs in computing the CMI ought to be feasible and valid in countries that have not implemented DRGs.
In the absence of cancer registry data, is it sensible to assess incidence using hospital separation records?
Authors: Brackley Moyra E , Penning Margaret J , Lesperance Mary L
Published: October 2006

Background

Within the health literature, a major goal is to understand distribution of service utilisation by social location. Given equivalent access, differential incidence leads to an expectation of differential service utilisation. Cancer incidence is differentially distributed with respect to socioeconomic status. However, not all jurisdictions have incidence registries, and not all registries allow linkage with utilisation records. The British Columbia Linked Health Data resource allows such linkage. Consequently, we examine whether, in the absence of registry data, first hospitalisation can act as a proxy measure for incidence, and therefore as a measure of need for service.

Methods

Data are drawn from the British Columbia Linked Health Data resource, and represent 100% of Vancouver Island Health Authority cancer registry and hospital records, 1990–1999. Hospital separations (discharges) with principal diagnosis ICD-9 codes 140–208 are included, as are registry records with ICDO-2 codes C00-C97. Non-melanoma skin cancer (173/C44) is excluded. Lung, colorectal, female breast, and prostate cancers are examined separately. We compare registry and hospital annual counts and age-sex distributions, and whether the same individuals are represented in both datasets. Sensitivity, specificity and predictive values are calculated, as is the kappa statistic for agreement. The registry is designated the gold standard.

Results

For all cancers combined, first hospitalisation counts consistently overestimate registry incidence counts. From 1995–1999, there is no significant difference between registry and hospital counts for lung and colorectal cancer (p = 0.42 and p = 0.56, respectively). Age-sex distribution does not differ for colorectal cancer. Ten-year period sensitivity ranges from 73.0% for prostate cancer to 84.2% for colorectal cancer; ten-year positive predictive values range from 89.5% for female breast cancer to 79.35% for prostate cancer. Kappa values are consistently high.

Conclusion

Claims and registry databases overlap with an appreciable proportion of the same individuals. First hospital separation may be considered a proxy for incidence with reference to colorectal cancer since 1995. However, to examine equity across cancer health services utilisation, it is optimal to have access to both hospital and registry files.
fMRI-compatible rehabilitation hand device
Authors: Khanicheh Azadeh , Muto Andrew , Triantafyllou Christina , Weinberg Brian , Astrakas Loukas , Tzika Aria , Mavroidis Constantinos
Published: October 2006

Background

Functional magnetic resonance imaging (fMRI) has been widely used in studying human brain functions and neurorehabilitation. In order to develop complex and well-controlled fMRI paradigms, interfaces that can precisely control and measure output force and kinematics of the movements in human subjects are needed. Optimized state-of-the-art fMRI methods, combined with magnetic resonance (MR) compatible robotic devices for rehabilitation, can assist therapists to quantify, monitor, and improve physical rehabilitation. To achieve this goal, robotic or mechatronic devices with actuators and sensors need to be introduced into an MR environment. The common standard mechanical parts can not be used in MR environment and MR compatibility has been a tough hurdle for device developers.

Methods

This paper presents the design, fabrication and preliminary testing of a novel, one degree of freedom, MR compatible, computer controlled, variable resistance hand device that may be used in brain MR imaging during hand grip rehabilitation. We named the device MR_CHIROD (
M
agnetic
R
esonance
C
ompatible Smart
H
and
I
nterfaced
R
ehabilitation
D
evice). A novel feature of the device is the use of Electro-Rheological Fluids (ERFs) to achieve tunable and controllable resistive force generation. ERFs are fluids that experience dramatic changes in rheological properties, such as viscosity or yield stress, in the presence of an electric field. The device consists of four major subsystems: a) an ERF based resistive element; b) a gearbox; c) two handles and d) two sensors, one optical encoder and one force sensor, to measure the patient induced motion and force. The smart hand device is designed to resist up to 50% of the maximum level of gripping force of a human hand and be controlled in real time.

Results

Laboratory tests of the device indicate that it was able to meet its design objective to resist up to approximately 50% of the maximum handgrip force. The detailed compatibility tests demonstrated that there is neither an effect from the MR environment on the ERF properties and performance of the sensors, nor significant degradation on MR images by the introduction of the MR_CHIROD in the MR scanner.

Conclusion

The MR compatible hand device was built to aid in the study of brain function during generation of controllable and tunable force during handgrip exercising. The device was shown to be MR compatible. To the best of our knowledge, this is the first system that utilizes ERF in MR environment.
S100B binding to RAGE in microglia stimulates COX-2 expression
Authors: Bianchi Roberta , Adami Cecilia , Giambanco Ileana , Donato Rosario
Published: October 2006

Besides exerting regulatory roles within astrocytes, the Ca2+-modulated protein of the EF-hand type S100B is released into the brain extracellular space, thereby affecting astrocytes, neurons, and microglia. However, extracellular effects of S100B vary, depending on the concentration attained and the protein being trophic to neurons up to nanomolar concentrations and causing neuronal apoptosis at micromolar concentrations. Effects of S100B on neurons are transduced by receptor for advanced glycation end produts (RAGE). At high concentrations, S100B also up-regulates inducible NO synthase in and stimulates NO release by microglia by synergizing with bacterial endotoxin and IFN-γ, thereby participating in microglia activation. We show here that S100B up-regulates cyclo-oxygenase-2 expression in microglia in a RAGE-dependent manner in the absence of cofactors through independent stimulation of a Cdc42-Rac1-JNK pathway and a Ras-Rac1-NF-κB pathway. Thus, S100B can be viewed as an astrocytic endokine, which might participate in the inflammatory response in the course of brain insults, once liberated into the brain extracellular space.
Insulin-Like Growth Factor-I Is an Important Antiapoptotic Factor for Rat Leydig Cells during Postnatal Development
Authors: Colón Eugenia , Zaman Farasat , Axelson Magnus , Larsson Olle , Carlsson-Skwirut Christine , Svechnikov Konstantin V. , Söder Olle
Published: October 2006

The present investigation examines the influence of IGF-I and the role of IGF-I receptor (IGF-IR) in the apoptosis/survival of Leydig cells. Immunohistochemical analysis of the rat testis at different ages revealed that the level of the phosphorylated IGF-IR increases from birth to d 20 of postnatal life, remaining high in the adult testis. Western blotting revealed that this level is higher in Leydig cells isolated from 40-d-old than from 10- or 60-d-old rats. Application of the terminal deoxyribonucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling assay revealed that IGF-I decreases the level of apoptosis in Leydig cells at all stages of development, and the selective inhibitor of IGF-IR, picropodophyllin, blocks this antiapoptotic effect. The mechanism underlying the antiapoptotic action of IGF-I involves the phosphatidylinositol 3-kinase/Akt pathway, and in immature Leydig cells, this growth factor enhances the expression of Bcl-2 and cellular inhibitor of apoptosis proteins 2, while preventing activation of caspase-3 by cleavage. Furthermore, IGF-II and high concentrations of insulin also evoke phosphorylation of IGF-IR and, like IGF-I, enhance the expression of the steroidogenic acute regulatory protein by Leydig cells. Inhibition of IGF-IR by picropodophyllin decreases the survival of Leydig cells, both in the presence and absence of IGF-I, demonstrating that signaling via the IGF-IR plays an important role in Leydig cell survival.
Three-dimensional model for gas tungsten arc welding with filler metal
Authors: Fan H G , Kovacevic R
Published: October 2006

This paper presents a three-dimensional model to describe the transient heat and fluid flow in gas tungsten arc welding (GTAW) with a filler metal. Using the volume of fluid (VOF) method, the melt depth and the surface profile of the weld are predicted. The GTAW experiments show that the predictions of the weld pool shape based on the model are in good agreement with the measured values.
Implications of the End-of-Life Vehicles Directive on the vehicle recovery sector
Authors: Edwards C , Coates G , Leaney P G , Rahimifard S
Published: October 2006

To cope with the environmental effects of 9 million tonnes of vehicles that reach the end of their useful lives each year in Europe, the EC have created the End-of-Life Vehicles (ELVs) Directive. Two of the most radical measures included in the Directive are to provide free takeback to last owners and to achieve targeted levels for the recycling and recovery of material by set dates. This paper aims to provide a basis for future research by evaluating the potential direction of the recovery industry. This is achieved firstly by assessing the origins of the directive and previous research surrounding the subject. The paper then describes the current recovery infrastructure and practices in the UK, highlighting all the stakeholders involved in the recovery industry. This paper also highlights the issues related to the provision of takeback and the attainment of targets through two stages, namely the implementation and management of takeback, and the use of new technology to achieve the recovery targets. The paper concludes by identifying key aims for future research to support the objectives of the implemented legislation and the financial stability of all stakeholders.
A Branch-and-Cut Algorithm Without Binary Variables for Nonconvex Piecewise Linear Optimization
Authors: Keha Ahmet B. , de Farias Ismael R. , Nemhauser George L.
Published: October 2006

We give a branch-and-cut algorithm for solving linear programs (LPs) with continuous separable piecewise-linear cost functions (PLFs). Models for PLFs use continuous variables in special-ordered sets of type 2 (SOS2). Traditionally, SOS2 constraints are enforced by introducing auxiliary binary variables and other linear constraints on them. Alternatively, we can enforce SOS2 constraints by branching on them, thus dispensing with auxiliary binary variables. We explore this approach further by studying the inequality description of the convex hull of the feasible set of LPs with PLFs in the space of the continuous variables, and using the new cuts in a branch-and-cut scheme without auxiliary binary variables. We give two families of valid inequalities. The first family is obtained by lifting the convexity constraints. The second family consists of lifted cover inequalities. Finally, we report computational results that demonstrate the effectiveness of our cuts, and that branch-and-cut without auxiliary binary variables is significantly more practical than the traditional mixed-integer programming approach.
Capacitated Multi-Item Lot-Sizing Problems with Time Windows
Authors: Brahimi Nadjib , Dauzère-Pérès Stéphane , Najid Najib M.
Published: October 2006

This research concerns a new family of capacitated multi-item lot-sizing problems, namely, lot-sizing problems with time windows. Two classes of the problem are analyzed and solved using different Lagrangian heuristics. Capacity constraints and a subset of time window constraints are relaxed resulting in particular single-item time window problems that are solved in polynomial time. Other relaxations leading to the classical Wagner-Whitin problem are also tested. Several smoothing heuristics are implemented and tested, and their results are compared. The gaps between lower and upper bounds for most problems are very small (less than 1%). Moreover, the proposed algorithms are robust and do not seem to be too affected when different parameters of the problem are varied.
Surgical management of previously untreated glomus jugulare tumors
Authors: Douglas J. Green , Brackmann Derald E. , De La Cruz Antonio , Nguyen Chi D. , Arriaga Moises A. , Telischi Fred F.
Published: October 2006

The treatment of glomus jugulare tumors is controversial. Changes in the surgical treatment of glomus jugulare tumors at The House Ear Clinic have allowed complete resection in 85% of patients with minimal morbidity and no surgical mortalities. Our experience with 52 previously untreated patients with glomus jugulare tumors is reviewed.

Two primary surgical techniques were used. The mastoid/neck approach was used in 9 patients with small tumors limited to the jugular bulb. The infratemporal fossa approach was used in the remaining 43 tumors. Lower cranial nerve preservation was possible in the majority of patients with normal preoperative function. Modifications in the management of the facial nerve during the infratemporal fossa approach have resulted in good recovery of facial function (House grade I/VI or II/VI) in 95% of patients. Most patients (85%) were able to fully resume all preoperative activities. Our results suggest that surgical management is the treatment of choice in younger patients with glomus jugulare tumors.
Particle repositioning maneuver for benign paroxysmal positional vertigo
Authors: Welling D. Bradley , Barnes Douglas E.
Published: October 2006

The recent demonstration of free‐floating particles in the endolymph of the posterior semicircular canal in patients with benign paroxysmal positional vertigo (BPPV)1 has renewed interest in the physiology and treatment of this entity. The particle repositioning maneuver (PRM) relocates the free‐floating particles from the posterior semicircular canal back into the utricle, relieving the patient of bothersome, often long‐standing vertigo.

This report represents a prospective study of 27 consecutive patients seen with a diagnosis of BPPV. Eighty‐four percent of the patients treated with the particle repositioning maneuver who had no other associated pathology were cured or significantly improved with this new technique. Two patients who failed conservative management went on to surgical intervention with the posterior semicircular canal occlusion.

The authors find the particle repositioning maneuver effective for many patients with benign positional vertigo and recommend it as the first‐line treatment modality for BPPV.
Interleukin‐8 expression in otitis media
Authors: Maxwell Kenneth S. , Leonard Gerald , Carpenter Robert , Kreutzer Donald L. , Fitzgerald John E. , Burleson Joseph A.
Published: October 2006

Based on recent studies in the authors' laboratory on the correlation of cytokines and inflammation in otitis media (OM), the authors hypothesized that in chronic otitis media with effusion (COME) interleukin‐8 (IL‐8) is responsible for 1. the accumulation of leukocytes in the middle ear cleft and 2. in situ leukocyte activation with subsequent tissue damage. Additionally, the authors hypothesized that IL‐8 expression is at least in part under the control of interleukin‐1 (IL‐1) and tumor necrosis factor (TNF). To begin to test this hypothesis, middle ear effusions (MEE) obtained from children ages 2 to 90 months (mean age, 29 months) undergoing tympanostomy tube placement for the presence of these inflammatory cytokines were analyzed. For these studies, IL‐8, interleukin‐1 β (IL‐1β), tumor necrosis factor‐α (TNF‐α), and tumor necrosis factor‐β (TNF‐β) were measured in MEE by radioimmunoassay (RIA) or enzyme‐linked immunoassay (ELISA). IL‐8, IL‐1β, TNF‐α, and TNF‐β were present in 92%, 67%, 77%, and 0% of effusions, respectively. The mean (± SEM) values for IL‐8, IL‐1β, and TNF‐α were 4805 (± 913) pg/mg, 4076 (± 1510) pg/mg, and 163 (± 90) pg/mg. Further analysis indicated that levels of IL‐8 correlated with IL‐1β (R2 = .500, P = .000) and TNF‐α (R2 = .387, P = .023). Thus the authors' studies clearly demonstrate that IL‐8 is consistently present in the MEE of children with COME and is strongly correlated with levels of IL‐1β and TNF‐α, both known inducers of IL‐8 production. These results support the authors' hypothesis that IL‐1β, TNF‐α, and IL‐8 are intimately involved in the inflammatory cascade in the middle ear and suggest regulation of these cytokines as possible sites of future therapeutic intervention in otitis media with effusion (OME).
Neonatal nasal deformities secondary to nasal continuous positive airway pressure
Authors: Loftus Bernadette C. , Ahn Jeffrey , Haddad Joseph
Published: October 2006

Nasal continuous positive airway pressure (CPAP) is being used more frequently in neonatal intensive care units to avoid endotracheal intubation and its attendant complications. Nasal deformities secondary to the nares‐occluding prongs employed to deliver the CPAP in former preterm infants have been recognized, and prevention and surgical treatment of these deformities are discussed. An awareness of the potential for these deformities is important to all pediatric otolaryngologists as nasal CPAP is gaining increasing favor as a primary treatment for respiratory disease of the newborn.
Evaluation of maxillary sinus aspiration in patients with fever of unknown origin
Authors: Lebeda Mark D. , Haller Jeffrey R. , Graham Scott M. , Hoffman Henry T.
Published: October 2006

The value of diagnostic maxillary sinus aspiration in patients with abnormal findings on sinus radiographs and fever of unknown origin is unclear. To better define indications for this procedure, the results of 51 sinus aspirations in 34 patients with fevers of unknown origin and abnormal findings on sinus radiographs were analyzed retrospectively. Results of aerobic and anaerobic cultures were evaluated in the context of clinical signs and symptoms at the time of the maxillary sinus puncture. Typical symptoms of paranasal sinus disease were found to be the best predictor of a positive culture. Of patients with sinusitis complaints, 86.4% had culture‐positive aspirations, whereas only 8.3% of patients without clinical symptoms of sinusitis had culture‐positive aspirations. This study indicates that symptoms of sinus disease play an important role in determining the benefit of sinus aspiration in this group of patients.
Heat shock proteins in acute otitis media
Authors: Egusa Kentaro , Huang Cheng‐Chun , Haddad Joseph
Published: October 2006

Heat shock proteins (hsps) are essential for the survival of cells under an environmental insult. To elucidate the relationship between these intracellular proteins and acute otitis media (AOM), the authors studied hsp production in guinea pigs with AOM induced by inoculation of Streptococcus pneumoniae into the middle ear. Animals were sacrificed 1,3, or 5 days after inoculation. Immunocytochemical study showed localization of hsp70 within the epithelium of infected ears, while the normal control epithelium showed very light staining. Western blot tests of the mucosal extraction confirmed the presence of hsp70 in otitis media. Enzyme‐linked immunosorbent assay (ELISA) showed that hsp levels were higher in the infected mucosa than in the normal control mucosa. In contrast, hsp60 was not stimulated in infected ears. This study showed that hsp70, and not hsp60, was produced in the AOM model.
Targets and dimensions of social comparison among people with spinal cord injury and other health problems
Authors: Buunk Abraham P. , Zurriaga Rosario , Gonzalez Pilar , Terol Carmen , Roig Sofia Lopez
Published: October 2006

The present research examined comparison targets and comparison dimensions among two Spanish samples of individuals facing serious illnesses and diseases. In Study 1, 90 older patients (mean age 66.36) with various age‐related diseases, particularly cardiovascular diseases and diabetes, indicated that they compared themselves most often with others with the same disease, next with others with another disease and least with people without health problems. They compared themselves more often on their mental state, symptoms and physical activities than on their social activities. Social comparison orientation (SCO) as an individual difference characteristic was associated with more frequent comparisons with particularly similar targets, and with more frequent comparisons of one's symptoms and physical activities. Neuroticism was correlated only with more comparisons of one's symptoms. Study 2 was conducted in a sample of 70 relatively young patients (mean age 43.97) with spinal cord injury (SCI). Overall, they compared themselves more often with others than the participants in Study 1, and they compared themselves to a similar extent with people with SCI as with people with another disease and with people without health problems. While they felt on average better off than people with other diseases and other people with SCI, people with SCI felt on average worse off than people without health problems. They compared themselves more often on physical activities than on any other dimension. Higher levels of stress and uncertainty were associated with more frequent comparisons with people without SCI, and with more frequent comparisons of one's mental state, one's symptoms and one's future perspectives. The discussion focuses on the theoretical relevance of the results for social comparison theory, and on the practical relevance of the findings for interventions.
Longitudinal gains in self‐regulation from regular physical exercise
Authors: Oaten Megan , Cheng Ken
Published: October 2006

Objectives. The purpose of the present study was to test whether the repeated practice of self‐regulation could improve regulatory strength over time.

Method. Regulatory performance was assessed at baseline, then at monthly intervals for a period of 4 months using a visual tracking task. Perceived stress, emotional distress, self‐efficacy and general regulatory behaviour were assessed by questionnaire. Following a 2‐month control phase, participants entered a 2‐month self‐regulation programme designed to increase regulatory strength: a programme of regular physical exercise.

Results. Relative to the control phase, participants who exercised showed significant improvement in self‐regulatory capacity as measured by an enhanced performance on the visual tracking task following a thought‐suppression task. During the regulatory exercise phase, participants also reported significant decreases in perceived stress, emotional distress, smoking, alcohol and caffeine consumption, and an increase in healthy eating, emotional control, maintenance of household chores, attendance to commitments, monitoring of spending and an improvement in study habits. The control phase showed no systematic changes in performance on the visual tracking task across sessions. Reports of perceived stress, emotional distress and regulatory behaviours were also stable across sessions.

Conclusions. The uptake and maintenance of an exercise programme over a 2‐month period produced significant improvements in a wide range of regulatory behaviours. Nearly every major personal and social problem has some degree of regulatory failure. The idea that the capacity for self‐regulation can be improved is therefore of vast practical importance.
Representative Elementary Volume Analysis of Sands Using X-Ray Computed Tomography
Authors: Razavi MR , Muhunthan B , Al Hattamleh O
Published: October 2006

The concept of a representative elementary volume (REV) provides an effective means of developing macroscopic measures in the description of granular materials. However, due to the difficulties associated with the measurement and characterization of granular microstructure the existence and size of an REV has remained largely conjectural. This study presents a systematic method to examine the characteristics of the REV using X-ray computed tomography images. The 3-D images of spherical glass beads, Silica sand, and Ottawa sand have been characterized using advanced image processing techniques. An interactive computer program is developed to study porosity variation within a sphere with increasing radius from the images of these materials. The porosity variation of Silica sand and Ottawa sand showed three characteristic regions: an initial fluctuation region due to microscopic variations, a constant plateau region, and a region with a monotonic increase/decrease due to heterogeneity. The homogenous medium of glass beads did not show the last region. The results show that for a random packing of spherical glass beads the REV is about two to three times of the identical average diameter. The radius for Silica sand composed mainly of elongated particles is between 5 to 11 times of d50 and for Ottawa sand composed mainly of subrounded particles is between 9 to 16 times of d50.
Empirical Research to Evaluate Ethics Committees' Burdensome and Perhaps Unproductive Policies and Practices: A Proposal
Authors: Levine Robert J.
Published: October 2006

The U.S. system for the protection of human research subjects, particularly its ethics committee or Institutional Review Board (IRB) component, is excessively burdened. Many commentators, myself included, are concerned that, as a consequence of these excessive burdens, the IRB is losing its effectiveness in safeguarding the rights and welfare of human subjects. I believe that IRBs devote too much time doing work that simply does not need to be done. Several routine practices of IRBs are highly time consuming and, in my opinion, not sufficiently productive to warrant their continuation in their present form. Empirical research can and should be done to evaluate the consequences of these practices. If they are found to be insufficiently cost-effective, they should be modified or abandoned. This would result in reducing the burdens on IRBs, freeing up reviewers' time and energy to concentrate on more important and productive pursuits. I suggest we begin by evaluating two routine practices: (1) The practice of conducting all continuing reviews of ongoing research at convened meetings of the IRB. (2) The practice of referring all adverse events to the IRB for its review.
Ethical Issues in Trauma-Related Research: A Review
Authors: Newman Elana , Risch Elizabeth , Kassam-Adams Nancy
Published: October 2006

Ethical decision-making about trauma-related studies requires a flexible approach that counters assumptions and biases about victims, assures a favorable ethical cost-benefit ratio, and promotes advancement of knowledge that can benefit survivors of traumatic stress. This paper reviews several ethical issues in the field of traumatic stress: Benefit and risks in trauma-related research, whether trauma-related research poses unique risks and if so what those might be, informed consent and mandatory reporting, and supervision of trauma-related research. For each topic, we review potential ethical issues, summarize the research conducted thus far to inform ethical practice, and recommend future practice, research questions and policies to advance the field so that research on trauma can continue to be a win-win situation for all stakeholders in the research enterprise.
Regional brittle extension in Quaternary sediments of Lanslebourg (Haute-Maurienne valley, western Alps)
Authors: Champagnac Jean-Daniel , Delacou Bastien , Tricart Pierre , Sue* Christian , Burkhard Martin , Allanic Cécile
Published: October 2006

Brittle tectonics of the internal zones of the Western Alps is characterized by important normal faulting and minor transcurent faulting. Two different directions of extension occur through time, but the age of transition remains unconstrained. In order to fill this gap, and to provide new neotectonic data, we studied faulted Quaternary peri-glacial deposits in the core of the W-Alpine belt (Contamines Quarry, Lanslebourg, Haute-Maurienne/Vanoise area). These glaciolacustrine and fluvio-glacial sediments are capped by a ground moraine, which is related to a small glacier advance that occurred during the latest deglaciation of the Arc Valley (Pleistocene-Holocene transition). The faults cross-cut the moraine and are younger than this latest glacier advance. They are not affected by ice-related loading and movement. These faults show normal components with moderate to high dips (50° to 80°) and small to medium vertical offsets (mm- to m- scale). Offsets are visible due to contrasted lithologies of the sediments. Conjugated dihedra with two fault orientations are recognized, namely N-S and NW-SE. These fault orientations are consistent with an E-W to ENE-WSW direction of extension, and an unknown (but possibly minor) part of transcurrence. This direction of extension is parallel to the Arc Valley, and to the downstream direction of the paleo-glacier, as well as to the shear direction of the loadcast structures created by the ice weight and flow. The different possible origins of the faults are discussed, but their orientation is likely to be tectonically driven. The directions of faulting are consistent with N-S and NW-SE regional faulting within the Cretaceous Schistes lustrés inferred by in situ analyses and remote sensing measurements. The distribution of faults in the quarry near a km-scale fault, as well as their cross-cutting relationships to the moraine and the shear figures, suggest that the faulting of the Quaternary sediments is guided by a regional (i.e. tectonic) stress field. Since the faulting is younger than the latest glacier advance (ca. 10 to 15 ky) and is consistent with the current orogen-perpendicular extension, we propose that the seismogenic extension occurred from (at least) the latest Pleistocene onward.
Removal of Hexavalent Chromium from Groundwater by Granular Activated Carbon
Authors: Han Ihnsup , Schlautman Mark A. , Batchelor Bill
Published: October 2006

Removal of hexavalent chromium, Cr(VI), from an artificial groundwater by two commercially available granular activated carbons (GACs) was investigated in batch and continuous‐flow column studies. Experimental parameters examined included solution pH, presence of dissolved oxygen (DO), and GAC pretreatment with reducing agents. As solution pH increased from 4 to 7.5, the amount of Cr(VI) removed by both GACs decreased significantly. Removal of DO from experimental systems enhanced GAC performance, but pretreatment of the GACs with reductants (ferrous iron or dithionite) did not improve Cr(VI) removal. Equilibration with 0.01 M dibasic potassium phosphate [to extract adsorbed Cr(VI)] followed by a wash with 0.02 N sulfuric acid [to remove precipitated‐sorbed Cr(III)] proved to be a viable method to regenerate carbons whose Cr(VI) removal capacities were exhausted. Performance of regenerated carbons exceeded that of virgin carbons, primarily because of the favorable adsorption of Cr(VI) at low pH values and the reduction of Cr(VI) to Cr(III) on acidic GAC surfaces. The presence of Cr(III) in acid wash solutions provides direct evidence that Cr(VI) is reduced to Cr(III) in GAC systems under relatively acidic conditions. Granular activated carbon performance during five complete cycles was consistently high, which suggests that such a system will be able to function over many operation cycles without deleterious effects.
Substrate Inhibition Kinetics of Phenol Biodegradation
Authors: Goudar Chetan T. , Ganji Shobha H. , Pujar Basayya G. , Strevett Keith A.
Published: October 2006

Phenol biodegradation was studied in batch experiments using an acclimated inoculum and initial phenol concentrations ranging from 0.1 to 1.3 g/L. Phenol depletion and associated microbial growth were monitored over time to provide information that was used to estimate the kinetics of phenol biodegradation. Phenol inhibited biodegradation at high concentrations, and a generalized substrate inhibition model based on statistical thermodynamics was used to describe the dynamics of microbial growth in phenol. For experimental data obtained in this study, the generalized substrate inhibition model reduced to a form that is analogous to the Andrews equation, and the biokinetic parameters max, maximum specific growth; Ks', saturation constant; and Ki', inhibition constant were estimated as 0.251 h 2 1 , 0.011 g/L, and 0.348 g/L, respectively, using a nonlinear least squares technique. Given the wide variability in substrate inhibition models used to describe phenol biodegradation, an attempt was made to justify selection of a particular model based on theoretical considerations. Phenol biodegradation data from nine previously published studies were used in the generalized substrate inhibition model to determine the appropriate form of the substrate inhibition model. In all nine cases, the generalized substrate inhibition model reduced to a form analogous to the Andrews equation suggesting the suitability of the Andrews equation to describe phenol biodegradation data.
Application of Feedback Control Based on Dissolved Oxygen to a Fixed‐Film Sequencing Batch Reactor for Treatment of Brewery Wastewater
Authors: Nguyen Anh‐Long , Duff Sheldon J.B. , Sheppard John D.
Published: October 2006

Treatment of brewery wastewater was performed using an aerobic fixed‐film sequencing batch reactor using a feedback control system based on dissolved oxygen concentration in the mixed liquor. This control system was modeled after the self‐cycling fermentation technique. The system was operated at 25 and 35 °C and under growthrate limiting conditions. Total biochemical oxygen demand (TBOD) removal efficiency was 83% after 3 hours at 25 °C and 92% after 1.5 to 2 hours at 35 °C. The treated effluent produced had a TBOD between 120 and 438 mg/L, with suspended solids contributing between 63 and 71% of the TBOD. Effectiveness of the treatment process might be improved if an efficient secondary clarifier was installed or if the suspended solids were removed from the brewery wastewater before treatment.
Modeling of Biological Particle Mixing in a Fluidized‐Bed Biofilm Reactor
Authors: Abdul‐Aziz Munif A. , Asolekar Shyam R.
Published: October 2006

Performance of fluidized‐bed biofilm reactors (FBBRs) greatly depends on the amount of biomass attached to the inert core support particles and overall bed voidage. Thus, for proper design of an FBBR, it is important to know the biological particle (bioparticle) mixing and bed expansion behavior, which in turn influence bed volume and consequently the residence time of the liquid phase. This paper first investigates the superiority of some of the predominantly used fluidization correlations for biological beds to predict bed voidage and, second, it investigates the implications of bioparticle mixing in FBBRs. The fluidization correlation suggested by Foscolo et al. (1983) was found to be superior to the more widely used Richardson and Zaki (1954) correlation to predict FBBR bed voidage. Furthermore, from the three different sets of published experimental results of bed voidage applied in this study, the fluidization correlation suggested by Foscolo et al. (1983), along with the terminal settling velocity equation suggested by Mulcahy and Shieh (1987), was found to be superior to other sets of correlations used in this study to predict bed voidage in an FBBR, having the lowest mean deviation of 12.7%. A mathematical model for fluidization of a binary bioparticle mixture is also presented in this paper to model the interaction of a variety of parameters, including upflow superficial liquid velocity, core support particle size and density, and biofilm thickness. Numerical simulations using this model revealed that, for sand‐like core support particles (density ranging from 1500 to 2700 kg/m 3), a complete segregation would likely occur in the bed with larger bioparticles at the top and smaller ones at the bottom. For charcoal‐ or polymer‐like core support particles (density ranging from 1050 to 1300 kg/m 3), a homogeneous bed made up of both larger and smaller bioparticles would likely occur. Comparison of the model predictions with published experimental results suggested excellent agreement.
New Hypothesis for Secondary Clarifier Performance Under Hydraulically Limited Conditions
Authors: Narayanan B. , Hough S.G. , Ooten R.J.
Published: October 2006

A new criterion called the effluent upflow velocity (EUV) is proposed as an important parameter affecting secondary clarifier performance under hydraulically limited conditions. Defined as the upflow velocity in the effluent withdrawal zone of a secondary clarifier, the EUV is proposed as having a direct link to clarifier performance in the presence of a wide range of particle size distributions in the effluent withdrawal zone. It is hypothesized that a wide range of particle size distributions in the effluent withdrawal zone of a clarifier could result from one of two factors: poor mixed liquor flocculation characteristics or strong density currents capable of resuspending previously settled floc. Consequently, in the presence of either of these factors, the EUV would likely show the best correlation with clarifier effluent suspended solids, more so than traditional hydraulic criteria such as the surface overflow rate or weir loading rate. Results from clarifier modifications completed at the County Sanitation Districts of Orange County's Wastewater Treatment Plant No. 2 in Huntington Beach, California, are presented in support of this hypothesis.
Determination of Cadmium and Lead Species in the Water Column of the Jose Antonio Alzate Reservoir, Mexico
Authors: Barceló Quintal Icela D. , Solís Correa Hugo E. , González Cortés Carmen , Avila Pérez Pedro , García Juan A.
Published: October 2006

Contamination by dissolved cadmium and lead was studied at two different depths at four sites of the Jose Antonio Alzate Reservoir in central Mexico. Total dissolved levels were found to be between 0.3 and 0.6 μg/L for cadmium and between 2.1 and 4.8 μg/L for lead. Chemical dissolved speciation showed primarily inorganic lead species, whereas cadmium species were detected in both inorganic and organic fractions. Most of the lead and cadmium species were removable by cationic exchange. No specific distribution trend was noted for the metal species in the reservoir, although a difference between the surface and bottom samples resulted from physical and chemical factors. Sedimentation and adsorption seemed to help with the natural scavenging process of reservoir water metals.
Occurrence and Distribution of Microbiological Indicators in Groundwater and Stream Water
Authors: Francy Donna S. , Helsel Dennis R. , Nally Rebecca A.
Published: October 2006

A total of 136 stream water and 143 groundwater samples collected in five important hydrologic systems of the United States were analyzed for microbiological indicators to test monitoring concepts in a nationally consistent program. Total coliforms were found in 99%, Escherichia coli in 97%, and Clostridium perfringens in 73% of stream water samples analyzed for each bacterium. Total coliforms were found in 20%, E. coli in less than 1%, and C. perfringens in none of the groundwater samples analyzed for each bacterium. Although coliphage analyses were performed on many of the samples, contamination in the laboratory and problems discerning discrete plaques precluded quantification. Land use was found to have the most significant effect on concentrations of bacterial indicators in stream water. Presence of septic systems on the property near the sampling site and well depth were found to be related to detection of coliforms in groundwater, although these relationships were not statistically significant. A greater diversity of sites, more detailed information about some factors, and a larger dataset may provide further insight to factors that affect microbiological indicators.
Use of Halophilic Bacteria in Biological Treatment of Saline Wastewater by Fed‐Batch Operation
Authors: Kargi F. , Dinçer A. R.
Published: October 2006

Biological treatment of saline wastewater by standard activated‐sludge cultures typically results in low chemical oxygen demand (COD) removal efficiencies as a result of plasmolysis of cells caused by high salt content (> 1%). Removal of salt from wastewater before biological treatment by reverse osmosis or ion exchange would be quite costly. However, inclusion of salt‐tolerant organisms in an activated‐sludge culture to improve treatment efficiency is a practical approach developed and presented in this article. Synthetic wastewater composed of diluted molasses, urea, phosphate, and different amounts of salt (0 to 5% sodium chloride) was treated in an aeration tank operated in fed‐batch mode. Halobacter halobium added to activated‐sludge culture was used in biological treatment, and results were compared with those obtained with the activated‐sludge culture alone. Halobacter addition produced significantly greater COD removal rates and efficiencies (% removal) at salt concentrations greater than 2% salt. At low salt concentrations, performances of both cultures were comparable. Results indicated that saline wastewater containing more than 2% salt can be treated effectively by Halobacter‐supplemented, activated‐sludge cultures, with COD removal efficiencies greater than 85% within 9 hours of fed‐batch operation.
Reduction of 2,4‐Dinitrotoluene with Graphite and Titanium Mesh Cathodes
Authors: Jolas J.L. , Pehkonen S.O. , Maloney S.W.
Published: October 2006

Electrochemical degradation of 2,4‐dinitrotoluene (DNT) in a bench‐scale reactor was studied, and a number of parameters including dissolved oxygen, current, voltage, and electrode shape and material were investigated. Quantified rates of degradation ranged from 0.003 to 0.008 min−1 for graphite and 0.003 to 0.06 min−1 for titanium. Products of degradation were identified as diaminotoluene (DAT) and azoxy dimers and, in some cases, were also quantified. An azoxy dimer was found only in experiments with dissolved oxygen, and regioselectivity favoring the first reduction at the para position was evident based on product studies. Degradation studies using a graphite rod cathode were mass‐transfer limited, while degradation studies using titanium mesh wire were not. The material of the electrode had a strong influence on degradation rates and on the way that different water quality parameters affect the rate of 2,4‐DNT degradation.
Fate of Pentachlorophenol (PCP) in an Anaerobic Digester
Authors: Chen Shyi‐Tien , Dong Joseph , Berthouex P.M. , Boyle W.C.
Published: October 2006

To investigate the potential use of an anaerobic digester for treating pentachlorophenol (PCP) wastes in wastewater treatment plants (WWTPs), the fate of PCP in a digester was examined. In this study, two laboratory‐scale anaerobic digesters were operated in parallel. One was dosed with PCP; the other was not and served as a control. Before any PCP addition, the digesters were seeded and fed with digested and raw sludges, respectively, from a local WWTP, then went through a lengthy startup period. When the digesters became stable, their overall performances were similar to the full‐scale digesters located at the WWTP. The fate study of PCP was conducted under steady‐state conditions using two methods: (a) using radioactively labeled 14C PCP and (b) studying mass conservation of added PCP. Steady state was assumed as the similarity of pH, daily digester gas production, and solids data between the PCP‐acclimated and control digesters. The 14C radioactivity, PCP, and chlorophenols were measured in the aqueous, solid, and gaseous phases. From the radioactively labeled PCP study, results showed that approximately 19.5% of 14C PCP was recovered from the aqueous phase, 78% from the solid phase, and 2.5% from gaseous phase. From the mass‐balance study, results indicated that chlorophenols present in the digester effluent contained 95% (molar basis) of 3‐monochlorophenol (16.8% in the aqueous phase), 4.5% of 3,4‐dichlorophenol (0.3%), and 0.5% of 3,5‐dichlorophenol (0.1%). No chlorophenols were detected in the gaseous phase.
Prediction of the Effect of Recirculation on the Effluent Quality of Anaerobic Filters by Empirical Models
Authors: Yu Hanqing , Wilson Francis , Tay Joo‐Hwa
Published: October 2006

The action of effluent recirculation on an anaerobic filter is complex, and there has been no consensus about its effect. In this study two models, established through linear regression analyses of experimental results from two anaerobic filters without recirculation, were modified and used to predict the effect of recirculation on effluent quality of anaerobic filters. The form of the models suggested that effluent recirculation would increase the output chemical oxygen demand (COD) concentration of the anaerobic filter treating municipal wastewater, whereas the effect of recirculation on the anaerobic filter treating soybean processing wastewater would be more complex. For a given raw COD concentration and hydraulic loading rate, it was predicted that there would be a threshold recirculation ratio (rt) for the anaerobic filter treating soybean wastewater. It was predicted that recirculation with a ratio less than rt would reduce output COD concentration and enhance performance of the anaerobic fiter, whereas recirculation with a ratio beyond rt would result in a greater output COD concentration and thus adversely influence performance. Subsequent experiments verified these predictions.