bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathophysiological correlates of two unique renal tubule lesions in rats with intestinal resection
Authors: Worcester Elaine , Evan Andrew , Bledsoe Sharon , Lyon Mark , Chuang Mark , Orvieto Marcello , Gerber Glenn , Coe Fredric
Published: October 2006

Rats with small bowel resection fed a high-oxalate diet develop extensive deposition of calcium oxalate (CaOx) and calcium phosphate crystals in the kidney after 4 mo. To explore the earliest sites of renal crystal deposition, rats received either small bowel resection or transection and were then fed either standard chow or a high-oxalate diet; perfusion-fixed renal tissue from five rats in each group was examined by light microscopy at 2, 4, 8, and 12 wk. Rats fed the high-oxalate diet developed birefringent microcrystals at the brush border of proximal tubule cells, with or without cell damage; the lesion was most common in rats with both resection and a high-oxalate diet (10/19 with the lesion) and was significantly correlated with urine oxalate excretion ( P < 0.001). Rats with bowel resection fed normal chow had mild hyperoxaluria but high urine CaOx supersaturation; four of these rats developed birefringent crystal deposition with tubule plugging in inner medullary collecting ducts (IMCD). Two rats fed a high-oxalate diet also developed this lesion, which was correlated with CaOx supersaturation, but not oxalate excretion. Tissue was examined under oil immersion, and tiny birefringent crystals were noted on the apical surface of IMCD cells only in animals with IMCD crystal plugging. In one animal, IMCD crystals were both birefringent and nonbirefringent, suggesting a mix of CaOx and calcium phosphate. Overall, these animals demonstrate two distinct sites and mechanisms of renal crystal deposition and may help elucidate renal lesions seen in humans with enteric hyperoxaluria and stones.
Soluble Guanylyl Cyclase Activation With HMR1766 Attenuates Platelet Activation in Diabetic Rats
Authors: Schäfer Andreas , Flierl Ulrike , Kobsar Anna , Eigenthaler Martin , Ertl Georg , Bauersachs Johann
Published: October 2006

Objective—

Platelet activation significantly contributes to cardiovascular morbidity and mortality in diabetes. An association between impaired NO-mediated platelet inhibition and platelet activation has recently been demonstrated in experimental diabetes. Guanylyl cyclase activation enhances the reduced signaling via the NO/cGMP pathway. We investigated whether chronic guanylyl cyclase activation would beneficially modulate platelet activation in experimental diabetes mellitus.

Methods and Results—

Diabetes was induced by streptozotocin-injection in male Wistar rats. After 2 weeks, treatment with either placebo or the guanylyl cyclase activator HMR1766 (10 mg/kg twice daily by gavage) was initiated. Two weeks later, in vivo platelet activation and in vitro platelet reactivity were assessed. Chronic treatment with HMR1766 enhanced NO/cGMP-mediated signaling in platelets from diabetic rats determined by in vivo phosphorylation of platelet vasodilator-stimulated phosphoprotein (VASP) at Ser
157
and Ser
239
. In parallel, platelet-binding of fibrinogen, surface-expression of P-selectin, appearance of platelet-derived microparticles, and platelet-aggregates with other blood cells were significantly reduced by chronic treatment with HMR1766.

Conclusion—

Chronic activation of soluble guanylyl cyclase in diabetic rats improved markers of platelet activation and is a rationale approach for prevention of adverse cardiovascular events in diabetes.
Supersaturation in the Wyoming CCN Instrument
Authors: Snider Jefferson R. , Petters Markus D. , Wechsler Perry , Liu Peter S. K.
Published: October 2006

Two thermal diffusion cloud condensation nuclei (CCN) instruments were intercompared using a nearly monodisperse test aerosol composed of sodium chloride and ammonium sulfate. The main objective of this work is the determination of the maximum steady-state supersaturation within a thermal diffusion chamber. This required analysis of the uncertainties associated with the calibration of the instrument’s plate temperature and light scattering measurement systems.

The fraction of test particles activating to form cloud droplets, the activated fraction, was evaluated over a range of dry particle diameters at four supersaturations. Values of both the particle size, corresponding to an activated fraction equal to 0.5, and the width of a fitted activation function were derived. The former was used to evaluate the maximum steady-state chamber supersaturation. These studies reveal three significant findings. First, the derived chamber supersaturation is ∼40% smaller than values based on temperature measured at the top and bottom of the diffusion chamber. Second, using deliquesced test particles, mobility selected at a prescribed relative humidity, it is shown that the 40% discrepancy is not the result of a test particle shape effect. Third, the width of the activation function is substantially larger than the width of the test particle size spectra.

Plausible explanations for the 40% bias are considered. Contributors are the unintentional overestimation of the temperature difference imposed across the CCN chamber and the implicit assumption that water at the top and bottom of the CCN chamber has a vapor pressure equal to that over pure water.
Retrieving Storm Electric Fields from Aircraft Field Mill Data. Part I: Theory
Authors: Koshak W. J.
Published: October 2006

It is shown that the problem of retrieving storm electric fields from an aircraft instrumented with several electric field mill sensors can be expressed in terms of a standard Lagrange multiplier optimization problem. The method naturally removes aircraft charge from the retrieval process without having to use a high-voltage stinger and linearly combined mill data values. It allows a variety of user-supplied physical constraints (the so-called side constraints in the theory of Lagrange multipliers) and also helps improve absolute calibration. Additionally, this paper introduces an alternate way of performing the absolute calibration of an aircraft that has some benefits over conventional analyses. It is accomplished by using the time derivatives of mill and pitch data for a pitch down maneuver performed at high (>1 km) altitude. In Part II of this study, the above methods are tested and then applied to complete a full calibration of a Citation aircraft.
Shattering and Particle Interarrival Times Measured by Optical Array Probes in Ice Clouds
Authors: Field P. R. , Heymsfield A. J. , Bansemer A.
Published: October 2006

Optical array probes are one of the most important tools for determining the microphysical structure of clouds. It has been known for some time that the shattering of ice crystals on the housing of these probes can lead to incorrect measurements of particle size distributions and subsequently derived microphysical properties if the resulting spurious particles are not rejected. In this paper it is shown that the interarrival times of particles measured by these probes can be bimodal—the “cloud” probes are more affected than the “precipitation” probes. The long interarrival time mode represents real cloud structure while the short interarrival time mode results from fragments of shattered ice particles. It is demonstrated for the flights considered here that if the fragmented particles are filtered using an interarrival time threshold of 2 × 10−4 s in three of the four cases and 1 × 10−5 s in the other, then the measured total concentration can be affected by up to a factor of 4 in situations where large particles are present as determined by the mass-weighted mean size exceeding 1 mm, or the exponential slope parameter falling below 30 cm−1. When the size distribution is narrow (mass weighted mean size <1 mm), ice water contents can be overestimated by 20%–30% for the cases presented here.
Caveolin-1 regulates expression of junction-associated proteins in brain microvascular endothelial cells
Authors: Song Li , Ge Shujun , Pachter Joel S.
Published: October 2006

Recent evidence from this laboratory indicated that reduced expression of caveolin-1 accompanied the diminished expression of tight junction (TJ)–associated proteins occludin and zonula occludens-1 (ZO-1) following stimulation of brain microvascular endothelial cells (BMECs) with the chemokine CCL2 (formerly called MCP-1). Because attenuated caveolin-1 levels have also been correlated with heightened permeability of other endothelia, the objective of this study was to test the hypothesis that reduced caveolin-1 expression is causally linked to the action of CCL2 on BMEC junctional protein expression and barrier integrity. This was achieved using adenovirus to nondestructively deliver caveolin-1 siRNA (Ad-siCav-1) to BMEC monolayers, which model the blood-brain barrier (BBB). Treatment with siRNA reduced the caveolin-1 protein level as well as occludin and ZO-1. Additionally, occludin exhibited dissociation from the cytoskeletal framework. These changes were attended by comparable alterations in adherens junction (AJ)–associated proteins, VE-cadherin and β-catenin, increased BMEC paracellular permeability, and facilitated the ability of CCL2 to stimulate monocytic transendothelial migration. Furthermore, treating BMECs with cavtratin, a synthetic cell-permeable peptide encoding the caveolin-1 scaffolding domain, antagonized effects of both Ad-siCav-1 and CCL2. These results collectively highlight caveolin-1 loss as a critical step in CCL2-induced modulation of BMEC junctional protein expression and integrity, and possibly serve a crucial role in regulating inflammation at the BBB.
Effects of 3-beta-diol, an androgen metabolite with intrinsic estrogen-like effects, in modulating the aquaporin-9 expression in the rat efferent ductules
Authors: Picciarelli-Lima Patrícia , Oliveira André G , Reis Adelina M , Kalapothakis Evanguedes , Mahecha Germán AB , Hess Rex A , Oliveira Cleida A
Published: October 2006

Background

Fluid homeostasis is critical for normal function of the male reproductive tract and aquaporins (AQP) play an important role in maintenance of this water and ion balance. Several AQPs have been identified in the male, but their regulation is not fully comprehended. Hormonal regulation of AQPs appears to be dependent on the steroid in the reproductive tract region. AQP9 displays unique hormonal regulation in the efferent ductules and epididymis, as it is regulated by both estrogen and dihydrotestosterone (DHT) in the efferent ductules, but only by DHT in the initial segment epididymis. Recent data have shown that a metabolite of DHT, 5-alpha-androstane-3-beta-17-beta-diol (3-beta-diol), once considered inactive, is also present in high concentrations in the male and indeed has biological activity. 3-beta-diol does not bind to the androgen receptor, but rather to estrogen receptors ER-alpha and ER-beta, with higher affinity for ER-beta. The existence of this estrogenic DHT metabolite has raised the possibility that estradiol may not be the only estrogen to play a major role in the male reproductive system. Considering that both ER-alpha and ER-beta are highly expressed in efferent ductules, we hypothesized that the DHT regulation of AQP9 could be due to the 3-beta-diol metabolite.

Methods

To test this hypothesis, adult male rats were submitted to surgical castration followed by estradiol, DHT or 3-beta-diol replacement. Changes in AQP9 expression in the efferent ductules were investigated by using immunohistochemistry and Western blotting assay.

Results

Data show that, after castration, AQP9 expression was significantly reduced in the efferent ductules. 3-beta-diol injections restored AQP9 expression, similar to DHT and estradiol. The results were confirmed by Western blotting assay.

Conclusion

This is the first evidence that 3-beta-diol has biological activity in the male reproductive tract and that this androgen metabolite has estrogen-like activity in the efferent ductules, whose major function is the reabsorption of luminal fluid.
Intensive care unit-acquired Stenotrophomonas maltophilia: incidence, risk factors, and outcome
Authors: Nseir Saad , Di Pompeo Christophe , Brisson Hélène , Dewavrin Florent , Tissier Stéphanie , Diarra Maimouna , Boulo Marie , Durocher Alain
Published: October 2006

Introduction

The aim of this study was to determine incidence, risk factors, and impact on outcome of intensive care unit (ICU)-acquired Stenotrophomonas maltophilia.

Methods

This prospective observational case-control study, which was a part of a cohort study, was conducted in a 30-bed ICU during a three year period. All immunocompetent patients hospitalised >48 hours were eligible. Patients with non-fermenting Gram-negative bacilli (NF-GNB) at ICU admission were excluded. Patients without ICU-acquired S. maltophilia who developed an ICU-acquired NF-GNB other than S. maltophilia were also excluded. Screening (tracheal aspirate and skin, anal, and nasal swabs) for NF-GNB was performed in all patients at ICU admission and weekly. Univariate and multivariate analyses were performed to determine risk factors for ICU-acquired S. maltophilia and for ICU mortality.

Results

Thirty-eight (2%) patients developed an S. maltophilia ICU-acquired colonisation and/or infection and were all successfully matched with 76 controls. Chronic obstructive pulmonary disease (COPD) and duration of antibiotic treatment (odds ratio [OR] [95% confidence interval (CI)] = 9.4 [3 to 29], p < 0.001, and 1.4 [1 to 2.3], p = 0.001, respectively) were independently associated with ICU-acquired S. maltophilia. Mortality rate (60% versus 40%, OR [95% CI] = 1.3 [1 to 1.7, p = 0.037]), duration of mechanical ventilation (23 ± 16 versus 7 ± 11 days, p < 0.001), and duration of ICU stay (29 ± 21 versus 15 ± 17 days, p < 0.001) were significantly higher in cases than in controls. In addition, ICU-acquired infection related to S. maltophilia was independently associated with ICU mortality (OR [95% CI] = 2.8 [1 to 7.7], p = 0.044).

Conclusion

COPD and duration of antibiotic treatment are independent risk factors for ICU-acquired S. maltophilia. ICU-acquired S. maltophilia is associated with increased morbidity and mortality rates. ICU-acquired infection related to S. maltophilia is an independent risk factor for ICU mortality.
TLR7/8 agonists impair monocyte-derived dendritic cell differentiation and maturation
Authors: Assier Eric , Marin-Esteban Viviana , Haziot Alain , Maggi Enrico , Charron Dominique , Mooney Nuala
Published: October 2006

Pathogen recognition by TLR activates the innate immune response and is typically followed by the development of an adaptive immune response initiated by antigen presentation. Dendritic cells (DC) are the most efficient APC and express diverse TLRs, including TLR7 and -8, which have been recently identified as targets for ssRNA recognition during viral infection. We have studied the effect of TLR7/8 agonists on DC differentiation and maturation from human monocytes. The synthetic agonist Resiquimod (R-848) or the physiological agonist ssRNA impaired monocyte differentiation to DC phenotypically and functionally. Induced expression of the nonclassical MHC molecules of the CD1 family in DC was inhibited at the protein and mRNA levels, and antigen acquisition was inhibited. Proinflammatory cytokine (including IL-6, IL-8, TNF-α, IL-1β) and IL-10 production were induced during DC differentiation. Cross-talk between TLR4 and TLR7/8 was revealed as immature DC, which had been differentiated in the presence of R-848 were insensitive to LPS-mediated maturation and cytokine production but still induced allostimulation. These data lead us to suggest that ongoing viral activation of TLR7/8 could alter the adaptive immune response by modifying DC differentiation and by down-regulating DC responsiveness to a subsequent bacterial TLR4-mediated signal.
Do Erythropoietin Receptors on Cancer Cells Explain Unexpected Clinical Findings?
Authors: Henke Michael , Mattern Dominik , Pepe Margaret , Bézay Christina , Weissenberger Christian , Werner Martin , Pajonk Frank
Published: October 2006

Purpose

Recent reports suggest that cancer control may worsen if erythropoietin is administered. We investigated whether erythropoietin receptor expression on cancer cells may correlate with this unexpected finding.

Patients and Methods

Cancer tissue from patients with advanced carcinoma of the head and neck (T3, T4, or nodal involvement) and scheduled for radiotherapy was assayed retrospectively for erythropoietin receptor expression by immunohistochemistry. Patients were anemic and randomized to receive epoetin beta (300 U/kg) or placebo under double-blind conditions, given three times weekly starting 10 to 14 days before and continuing throughout radiotherapy. We administered 60 Gy following complete resection or 64 Gy subsequent to microscopically incomplete resection; 70 Gy were given following macroscopically incomplete resection or for definitive radiotherapy alone. We determined if the effect of epoetin beta on locoregional progression-free survival was correlated with the expression of erythropoietin receptors on cancer cells using a Cox proportional hazards regression model.

Results

We studied 154 of 157 randomly assigned patients; 104 samples were positive, and 50 were negative for receptor expression. Locoregional progression-free survival was substantially poorer if epoetin beta was administered to patients positive for receptor expression compared with placebo (adjusted relative risk, 2.07; 95% CI, 1.27 to 3.36; P < .01). In contrast, epoetin beta did not impair outcome in receptor-negative patients (adjusted relative risk, 0.94; 95% CI, 0.47 to 1.90; P = .86). The difference in treatment associated relative risks (2.07 v 0.94) was borderline statistically significant (P = .08).

Conclusion

Erythropoietin might adversely affect prognosis of head and neck cancer patients if cancer cells express erythropoietin receptors.
Laryngeal injury from prolonged endotracheal intubation
Authors: Weymuller Ernest A.
Published: October 2006

This project was undertaken to develop models of acute and chronic laryngeal intubation as a format for testing a newly designed endotracheal tube. The tube has a specially created laryngeal cuff designed to reduce pressure exerted against the laryngeal soft tissues. The laryngeal foam cuff was shown to prevent the injurious sequence of mucosal ischemia, ulceration, and cartilage damage.

A laryngeal foam cuff has the potential to significantly reduce laryngeal injury from prolonged endotracheal intubation. A prospective randomized clinical trial has been initiated and will be reported subsequently.
Fluctuating and/or progressive sensorineural hearing loss in children
Authors: Brookhouser Patrick E. , Worthington Don W. , Kelly William J.
Published: October 2006

Sensorineural hearing loss (SNHL) which is sudden in onset, fluctuating, and/or progressive complicates medical management, hearing aid selection, and individualized educational planning for a hearing‐impaired child. In spite of multidisciplinary evaluation and intervention, a gradual decrease in auditory acuity may continue unabated in a significant number of cases. Intercurrent middle ear disease and inconsistent audiologic technique can account for threshold variation in some cases. The study population consisted of 229 children (132 boys; 97 girls) aged 1 to 19.9 years at first audiogram which revealed at least a mild degree of sensorineural hearing loss in one or both ears (35 unilateral), and who demonstrated threshold variation of 10 dB or more in at least one ear at one or more of the standard audiometric test frequencies (250, 500, 1000, 2000, 4000, and 8000 Hz) and were without concurrent middle ear disease (mean length of follow‐up, 4.9 years; mean number of audiograms, 10.3). Of 365 ears demonstrating threshold variation of 10 dB or more, 22 (6%) had purely progressive losses without intercurrent upward fluctuation, 208 (57%) had fluctuating thresholds with gradually progressive losses, and 135 (37%) had intermittent threshold fluctuation without permanent deterioration. The probability of contralateral threshold fluctuation if one ear fluctuated was 0.91, while the probability of contralateral progressive SNHL if one ear progressed was 0.67. Demographic data, presumptive etiology, degree of initial SNHL, audiometric configuration, and symmetry of threshold variation were considered as potential predictors of the likelihood of threshold fluctuation and/or progression.
Dose response of human tumor cells to rhodamine 123 and laser phototherapy
Authors: Saxton Romaine E. , Haghighat Sherry , Castro Dan J. , Plant David , Lufkin Robert , Soudant Jacque
Published: October 2006

Previous studies have shown that Rhodamine 123 (Rh123) is an efficient tumor targeting agent for argon laser photodynamic therapy in vitro. Effectiveness of this approach for cancer treatment in vivo will depend on Rh123 tumor uptake kinetics and laser energy delivery via fiberoptics to the tumor site. In the present study, tumor and normal cells were exposed in vitro to 1 μg/mL Rh123 until 10%, 50%, and 100% of maximum uptake was achieved. Laser treatment response was monitored by trypan blue exclusion for tumor cell viability and by MTT tetrazolium assays to measure mitochondrial dehydrogenase activity. TE671 fibrosarcoma cells were highly sensitive to argon laser phototherapy (514 nm, 5 W, 1 minute, Tmax = 8°C), with mitochondrial inhibition seen after Rh123 uptake of 12, 50, and 100 ng/million cells. P3 squamous cell carcinoma cells were inhibited 20% and 75% by the laser after Rh123 uptake of 13 or 30 ng/million cells, respectively. M26 melanoma cells were not sensitive to the laser after 15 ng/million cells Rh123 uptake but were inhibited 45% and 75% after Rh123 uptake of 80 and 160 ng/million cells. Micro2 fibroblast mitochondrial activity was reduced less than 25% by the laser after Rh123 uptake of 50 ng/million cells. Cell viability after maximum Rh123 uptake and laser treatment was decreased to 30%, 15%, and 2% for M26 melanoma, P3 squamous cell carcinoma, and TE671 fibrosarcoma cells, but remained over 80% for Micro2 fibroblasts. The results suggest that Rh123 laser treatment response depends on tumor type and drug uptake level, with normal cells being much less sensitive to phototherapy.
Evaluation of cervical lymph node metastases in squamous cell carcinoma of the head and neck
Authors: Don Debra M. , Calcaterra Thomas C. , Anzai Yoshimi , Lufkin Robert B. , Fu Yao‐Shi
Published: October 2006

Although computed tomography and magnetic resonance imaging have contributed to the ability to identify metastatic disease in head and neck Cancer, inadequacies in evaluating lymphadenopathy still exist. This study was undertaken to estimate the accuracy of radiological criteria used to detect cervical lymph node metastases. The morphological characteristics of 957 lymph nodes from 36 neck dissections from patients with squamous cell Cancer were examined microscopically. A large number of malignant nodes were found to have diameters of less than 10 mm. Extranodal spread also occurred in a substantial percentage of smaller nodes. Because the present radiological criteria for assessing cervical lymph node Status are based largely on size, findings indicate major limitations in the capabilities of detecting metastatic disease. New modalities to improve the Staging of head and neck Cancer are discussed.
Prevention of pharyngocutaneous fistulas by means of laser‐weld techniques
Authors: Shohet Jack A. , Reinisch Lou , Ossoff Robert H.
Published: October 2006

Although much has been written on methods of dealing with pharyngocutaneous fistulas once they have formed, there are few reports of methods of preventing fistula formation from occurring. We examined the use of laser‐weld techniques with the neodymium:yttrium aluminum garnet (Nd:YAG) and diode lasers to seal pharyngotomy closures. Laser‐weld techniques have been used successfully in many other tissues, but reports documenting use in the upper aerodigestive tract are minimal. Indocyanine‐green dye‐enhanced collagen and fibrinogen were studied as laser solder materials for the diode laser. Twenty‐nine experimental animals were studied. Neither the Nd:YAG nor the diode laser was successful in preventing fistula formation. Tensiometric studies documented significant strength of the laser welds ex vivo, but this finding was not clinically significant.
The meaning of self‐perception of health in the UK armed forces
Authors: Rona Roberto J. , Hooper Richard , French Claire , Jones Margaret , Wessely Simon
Published: October 2006

Objectives. We assessed the characteristics of self‐perception of health (SPH) in relation to psychological distress and physical symptoms, and willingness of servicemen to see their Medical Officer (MO) by their SPH rating.

Design. We randomly selected 4,500 servicemen to receive either a full or an abridged screening questionnaire.

Measures. The full questionnaire included 6 items from the short‐form 36 and the question on SPH, the General Health Questionnaire‐12, the post‐traumatic stress disorder checklist and 15 symptoms. The abridged questionnaire included a subset of items from the full questionnaire. All ‘screen‐positive’ and a random ‘screen‐negative’ sample were invited to see an MO.

Results. 67.1% out of 4,500 servicemen completed the questionnaires. SPH was strongly associated with a summary short form‐36 (SF‐36) measure. There was a strong association between SPH and all assessment scales regardless of length of the questionnaires (p <.001). Even among those with very good or excellent SPH, high scores denoting psychological distress were prevalent (8.1%). Good SPH provided the largest variations in symptoms and scores. Servicemen with a poor /fair SPH were no more likely to accept a visit to the MO than the rest.

Conclusions. SPH is an excellent question for surveillance because it is highly associated with psychological health but, at an individual level, it may convey different meanings depending on the person's individual interpretation of the term health. Symptomatic social avoidance may be high among servicemen who have a poor /fair SPH and methods, such as buddy support, may be helpful in decreasing isolation among those who may need professional support.
Falling-Head Permeability Tests in an Unconfined Sand Aquifer
Authors: Chapuis RP , Dallaire V , Gagnon F , Marcotte D , Chouteau M
Published: October 2006

This paper examines the reliability of hydraulic conductivity estimates, k, obtained using equations of Hvorslev (1951) or Bouwer and Rice (1976) for falling-head tests in monitoring wells (MWs) having short screens at the bottom of an unconfined sand aquifer. Two issues are examined. First, the equations come from the theory of steady-state flow whereas a variable-head test means transient flow with a changing water table position. This first problem was investigated using a finite element analysis, taking into account the sand capillary retention curve and its saturated-unsaturated permeability. The main result was that the equations can still be used for variable-head tests. The effects of specific storage (elastic deformation of the solid matrix in saturated conditions) and delayed gravity drainage (frequently schematized by a specific yield) can be neglected for these tests. The second issue is how partial clogging or fine particle washing against the screen can influence the k value. This practical problem was investigated by using a surge block to develop MWs and then performing successive permeability tests to assess the effects of development. Before development, the tests provided k values in the range 1 to 12×10-2 cm/s, the average being equal to 2/3 of the large-scale k value obtained using a pumping test under steady-state condition. After development, the tests provided k values that were increased by 50% on average, and thus their mean value became almost equal to the pumping test k value.
Thermoelastic Transformation Behavior of Nitinol
Authors: Perry KE , Labossiere PE , Steffler E
Published: October 2006

The transformation behavior of Nitinol under uniaxial tension and four-point bending was investigated. A novel sample geometry produced from drawn tubing was used to observe the differences caused by localized phase transformation effects between the two types of loading and between samples with different process and load histories. Phase shifted moir interferometry was used to provide full-field measurement of strain during the experiments. Optical resolution and grating coherence were sufficient to simultaneously resolve the strain fields within both the parent and transformed phases of the material. Evidence of both localized and uniformly distributed phase transformation is observed for the samples tested in tension while the bending results clearly indicate an asymmetric neutral axis and a complex reverse bending response for samples containing a strong R-phase component and tested at temperatures below critical transformation temperatures.
Impact of Adjuvants on Droplet Spreading and Droplet Deposit Area After Spray Application
Authors: Baur P
Published: October 2006

The effects of adjuvants on spreading of small droplets after spray application and of larger drops with volumes in the microliter range was studied. The characterization of spreading as affected by adjuvants is done often with lab tests on artificial surfaces. In these tests much larger drops in the microliter range are used and plant factors such as the presence of hairs or crystalline waxes and spray related factors such as rapid evaporation, a different drop size magnitude, a drop size distribution in reality, and effects of adjuvants on drop size are not considered. For a set of test compounds from different chemical classes we evaluated stepwise the approximation to real systems with plant surfaces representing the major surface features. With larger drops of 10 and 20 μl we obtained a surprisingly good correlation of spreading on Parafilm® M and the mature leaves of Chlorophytum, tomato, rape, and corn. With good wetters better spreading was observed on leaves than on Parafilm M. The correlation of spread diameters with real spray (flat fan nozzle, 300 l/ha) on an easily wettable plant and drops on Parafilm M was very good as well though with the best spreaders the gravimetric momentum on spreading and longer times for evaporation overestimated spreading of the larger droplets on Parafilm M. If the mean spread diameters of real spray was plotted vs. the logtransformed spread diameter on Parafilm M a linear correlation was obtained (r2=0.92).
Realistic Approach for Enhancing Reliability of Pavement Surface Friction Testing
Authors: Li S , Noureldin S , Zhu K
Published: October 2006

This paper presents the state-of-the-practice by the Indiana Department of Transportation (INDOT) in enhancing the reliability of pavement friction testing with the ASTM Standard E 274-97 [1] locked wheel tester. In order to detect the potential changes in system performance, INDOT conducts weekly and monthly system verification on a special friction test track. A multiparameter method has been used in assessing the performance of the locked wheel tester. This method cross examines the sample mean, the standard deviation, and the coefficient of variations of the friction measurements saved in a dynamic friction database that is upgraded after each verification testing. It was found that the system performance of the locked wheel tester varies with the type of test tire and pavement surface characteristics. The smooth tire produces greater friction variations than the ribbed tire. As pavement surface becomes rougher, friction variations decrease. A realistic approach has been established for verifying system performance.
Faults and matrix deformations in chalk: contribution of porosity and sonic wave velocity measurements
Authors: Schroeder Christian , Gaviglio Patrick , Bergerat Françoise , Vandycke Sara , Coulon Michel
Published: October 2006

Measurements of sonic wave velocity and of porosity have been carried out on the Campanian so-called “craie blanche” (white chalk) of the Mons Basin. They have been made on cores collected perpendicular to normal fault planes, at different distances, between 0 (fault plane) and 30 cm. The applications of the continuity index, deduced from the sonic velocity, to these measurements allow us to estimate the amount of microcracking. A new evaluation of the used coefficients, after the physical characteristics of the intact material, has been necessary. The systematic comparison of the values of both velocity and porosity highlight the matrix transformations (decreasing of porosity by calcitic cementation) in a narrow band of about 10 cm on both sides of the fault planes. Depending on the stratigraphic level, the porosity of the intact chalk ranges between 40 and 44% and the sonic wave velocity between 2300 and 2600 m/s. Close to the fault planes, the porosity is about 30 to 35% and the sonic wave velocity about 2700 to 2900 m/s. Along the fault planes, the rock material has an anisotropic behaviour, due to both vertical tectonic microcracking and calcitic barriers resulting from cementation.
Effectiveness of Natural Treatment in a Wastewater Irrigation District of the Mexico City Region: A Synoptic Field Survey
Authors: Downs Timothy J. , Cifuentes Enrique , Ruth Edward , “Mel” Suffet Irwin
Published: October 2006

Untreated wastewater from Mexico City has been used for decades to irrigate the Mezquital Valley, Hidalgo, Mexico. A synoptic survey of the natural treatment systems was carried out using the criteria of 24 trace metals, 67 target base/neutral/acid (BNA) semivolatile organic compounds, nontarget BNA semivolatile organics, nitrate, 23 chlorinated pesticides, and a 20 congener polychlorinated biphenyl (PCB) suite. Data suggest the irrigation region is acting as a huge open‐system slow sand filter, the main reservoir as a large waste stabilization lagoon, and the canals as extremely long, narrow stabilization channels. The BNA levels in surface water (SW) after reservoir retention were much lower than before it, while levels in groundwater (GW) were significantly lower than SW. All GW nitrate levels exceeded drinking water standards and were greater than those in SW. Metal levels in GW were below drinking water standards, and SW levels exceeded them for only a few metals. Low to moderate levels of organochlorine pesticides and PCBs were found.
Feasibility Study of Complete Nitrogen Removal from Domestic Wastewater by Consequent Nitrification–Denitrification Using Immobilized Nitrifiers in Gel Beads
Authors: Libman Vyacheslav , Eliosov Boris , Argaman Yerachmiel
Published: October 2006

A two‐stage process for complete removal of nitrogen from domestic wastewater is proposed in this paper. The two stages of this process are an aerobic stage using nitrifying microorganisms immobilized in gel beads and a conventional anoxic stage. The possible application of gel‐entrapped biomass for high‐rate, complete nitrogen removal from domestic wastewater was verified through theoretical and experimental work. Two assumptions were confirmed in the present work: (a) substances present in domestic wastewater do not inhibit nitrification, and (b) heterotrophic biomass that builds up on the surface of nitrifying beads is not expected to affect ammonium oxidation or remove a significant part of the biochemical oxygen demand required for denitrification. The effect of the attached heterotrophic layer on system performance was evaluated through theoretical prediction and short‐term experiments. Calculations indicated that complete nitrogen removal could be achieved if the heterotrophic layer on 2‐mm gel beads is less than 12 m thick. The heterotrophic biofilm observed in the experiments did not homogeneously spread over the entire bead surface. It was found that attached growth of heterotrophs is affected by mixing intensity and type of carrier material.
Evaluation of the Multichambered Treatment Train, a Retrofit Water‐Quality Management Practice
Authors: Greb Steven R. , Bannerman Roger T.
Published: October 2006

This study evaluated the water‐quality benefits of a new urban best management practice design called the multichambered treatment train (MCTT). The study consisted of collecting flow‐weighted water‐quality samples at influent and effluent locations for 15 consecutive storms. Device efficiencies were based on load reductions of 68 constituents. Total rainfall amounts for the 15 storms ranged from 0.45 to 3.48 cm, yielding 1.7 to 8.9 m3 of water treated by the device. None of these storms surcharged the unit. High reduction efficiencies were found for all particulate‐associated constituents, such as total suspended solids (98%), total phosphorus (88%), and total recoverable zinc (91%). Dissolved fractions had substantial but somewhat lesser removal rates (dissolved phosphorus, 78%; dissolved zinc, 68%). Total dissolved solids, which originated from road salt storage, yielded 4 times the total suspended solids load. No appreciable shift was seen between influent and effluent particle size distributions.
Comparison of Dynamic and Steady‐State Models for Determining Water Quality Based National Pollutant Discharge Elimination System Limits for Toxics
Authors: Dilks David W. , Pendergast James F.
Published: October 2006

Current U.S. Environmental Protection Agency guidance allows water quality based effluent limits for toxic substances to be based on one of two types of water quality models: steady state and dynamic. The intention of both types of models is to limit occurrence of instream toxicity to a frequency of no greater than once in 3 years. Steady‐state models are used to predict concentrations for a single critical (i.e., almost worst‐case) combination of effluent and environmental conditions. These models assume that effluent limits that are protective for critical conditions will also be in compliance with the less than once‐in‐3‐year frequency of toxicity objective. Dynamic (or probabilistic) models explicitly consider the variability in all model inputs and define effluent limits that will be in direct compliance with the once‐in‐3‐year goal. Essentially all published comparisons of steady‐state and dynamic model results have indicated that steady‐state models are more protective than dynamic models, leading to the commonly held assumption that steady‐state models are always overprotective. This assumption was evaluated by comparing steady‐state and dynamic wasteload allocation model results with 10 different sites across the United States. At 8 of the 10 sites, steady‐state modeling resulted in more lenient effluent limits. The primary factor that determines which wasteload allocation model produces the more stringent result was found to be the variation in receiving water assimilative capacity. Steady‐state analyses are less stringent than dynamic models for cases when there is a small variability in receiving water assimilative capacity. For systems with more variable assimilative capacity, the steady‐state model may be more stringent, depending on the severity of the critical condition selected. Equations are derived that allow a direct comparison of the two methods for simple single‐discharge situations.
Influence of Phytoplankton Composition on Biomass Removal from High‐Rate Oxidation Lagoons by Means of Sedimentation and Spontaneous Flocculation
Authors: García Joan , Hernández‐Mariné Mariona , Mujeriego Rafael
Published: October 2006

The objective of this study is to analyze the influence of phytoplankton species composition on biomass removal from high‐rate oxidation ponds or lagoons (HROPs) by means of sedimentation with spontaneous flocculation. Two experimental systems each consisting of an HROP (with a surface area of 1.54 m2 and depth of 0.3 m) with a clarifier (surface area = 0.025 m2) for phytoplankton biomass removal were operated with different hydraulic retention time criteria over a period of a year. Phytoplankton biomass removal rates reached a yearly average of 70 to 80% in both HROPs. During periods with large amounts of the algal species Scenedesmus acutus, which was present as discrete, unflocculated particles, both systems operated unsatisfactorily, with effluent total suspended solids (TSS) concentrations greater than 30 mg/L. Phytoplankton biomass removal from HROPs by means of sedimentation and spontaneous flocculation is unreliable for year‐round use (at least for 6 months of the year) if TSS effluent concentration is required to be less than 30 mg/L. Additional treatment, such as pH or chemical augmentation, is needed to reduce TSS and improve the effluent quality of HROPs with clarifiers.
Laboratory Treatability Study on Hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine(RDX‐) Contaminated Soil from the Iowa Army Ammunition Plant, Burlington, Iowa
Authors: Boopathy R. , Manning J.F.
Published: October 2006

Soil in certain areas of the Iowa Army Ammunition Plant in Burlington, Iowa, was contaminated with hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX). A laboratory treatability study was conducted to examine the ability of native soil bacteria present in the contaminated site to degrade RDX. The results indicated that RDX can be removed effectively from the soil by native soil bacteria through a co‐metabolic process. Molasses, identified as an effective cosubstrate, is inexpensive, and this factor makes the treatment system cost effective. The successful operation of aerobic–anoxic soil‐slurry reactors in batch mode with RDX‐contaminated soil showed that the technology can be scaled up for field demonstration. The RDX concentration in the contaminated soil was decreased by 98% after 4 months of reactor operation. The advantage of the slurry reactor is the simplicity of its operation. The method needs only mixing and the addition of molasses as cosubstrate.
Diagnosis and Identification of Respirometer Dynamics and Sludge Kinetics in Continuous‐Flow Respirometers
Authors: Lukasse Leo , Keesman Karel , Spanjers Henri , Bloemen Michiel
Published: October 2006

This paper deals with excitation of respiration chamber dynamics in a continuous‐flow respirometer with the objective of extracting additional information from its dissolved oxygen (DO) sensor readings. A measurement strategy is proposed from which it is theoretically possible to identify respiration chamber dilution rate, DO sensor dynamics, sludge kinetics, and short‐term biochemical oxygen demand (BODst) concentration in the inflow to the respirometer. In extensive experiments with activated sludge fed with municipal wastewater, the method for identifying respiration chamber dilution rate and DO sensor dynamics proved successful and was illustrated to be useful. Finally, the results convincingly discourage further efforts to identify sludge kinetics and BODst from this type of experiment, despite the theoretical feasibility.
Effect of Drinking Water Sources on Reclaimed Water Quality in Water Reuse Systems
Authors: Drewes Jörg E. , Fox Peter
Published: October 2006

The objective of this study was to investigate how natural organic matter from drinking water and soluble microbial products generated in the wastewater treatment process influence the character of dissolved organic carbon (DOC) in reclaimed water used for indirect potable reuse. Arizona and California water reuse field sites with different drinking water source quality and applied wastewater treatment were investigated using a watershed guided approach. Based on hydraulically corresponding samples of drinking water and reclaimed water, a correlation between the city of Mesa, Arizona, drinking water DOC and reclaimed water DOC after soil‐aquifer treatment (SAT) was derived, indicating that up to 70% of the residual DOC after SAT originated from Mesa drinking water DOC. Based on nonpolar resin adsorption‐ (XAD‐) isolation, followed by 13carbon‐nuclear magnetic resonance spectroscopy (13C‐NMR), residual DOC in reclaimed water after SAT was dominated at all investigated sites in concentration and character by natural organic matter and showed 13C‐NMR spectra similar to the corresponding surface water isolates. The results imply that water‐quality properties of source water play a key role in wastewater properties and variability and in subsequent soil‐aquifer treatment impacts.
Nonbiodegradable Organic Compounds Found in Automotive Spraybooth Scrubber Water
Authors: Kim B.R. , Zinbo M. , Adams J.A. , Young W.C.
Published: October 2006

Emissions of volatile organic compounds (VOCs) from painting operations are the largest source of manufacturing emissions for the automotive industry and are costly to control. While investigating the biological degradation of paint solvents in spraybooth scrubber water as a cost‐effective VOC control scheme, it was discovered that a significant portion (10 to 20%) of dissolved organics in the water was not biodegradable. All detected paint solvents were degraded, however. Therefore, raw and biologically treated scrubber water samples were analyzed to identify and quantify the nonbiodegradable organics by combined chromatographic, spectroscopic, and thermogravimetric methods. Results indicate that the nonbiodegradable compounds consisted mostly of nitrogen‐containing organic polymers (more than 70%) and other organics. The nitrogen‐containing compounds are believed to have come mostly from paints and possibly from polymeric detackifiers. Other organics included silicon‐containing compounds that might have come from paint additives and maintenance chemicals used at the plant.
Modeling the Inactivation of Particle‐Associated Coliform Bacteria
Authors: Emerick Robert W. , Loge Frank J. , Ginn Tim , Darby Jeannie L.
Published: October 2006

An equation was derived for describing the measured inactivation of particle‐associated coliform bacteria in wastewater secondary effluent exposed to UV light disinfection. Parameters of importance are the inactivation rate coefficient and the total number of particles that contain coliform bacteria. Prediction of coliform bacteria dose–response is possible to within the error associated with the multiple‐tube fermentation test. The theoretically derived modeling equation can be used with other design approaches that have specific strengths (e.g., incorporation of regulatory permit limitations or hydraulic characteristics). A minimum particle size seems to govern the ability of a particle to shield coliform bacteria from UV light. Particles smaller than that size do not contain regions shielded from UV light. At sizes greater than the critical particle size, size is not significant in determining shielding of coliform bacteria. Coliform bacteria are not typically located in the most shielded regions within particles, and therefore the inactivation of coliform bacteria within a particle does not indicate the application of UV light throughout that particle.
Comparison and Validation of UV Dose Calculations for Low‐ and Medium‐Pressure Mercury Arc Lamps
Authors: Wright Harold B.
Published: October 2006

A method for calculating UV dose for microbial disinfection that includes a measure of the wavelength‐dependent factors of UV lamp output, quartz sleeve UV transmission, microbial action spectra, and wastewater UV transmission is presented. The method is validated by comparing UV dose–response curves for the disinfection of a secondary effluent achieved using collimated beams of UV light generated from low‐ and medium‐pressure mercury arc lamps. The wastewater UV transmittance is artificially altered as part of the validation process. A simplified and practical method of UV dose calculation that relies only on a measure of the UV transmission at 254 nm is proposed for the disinfection of domestic wastewaters by mediumpressure lamps. The proposed method is validated using wastewater samples obtained from 21 wastewater treatment plants located across North America.