bluuebunny/crossref_metadata_2025 huggingface dataset:
Poor Growth of Rainbow Trout Fed New Zealand Mud Snails Potamopyrgus antipodarum
Authors: Vinson Mark R. , Baker Michelle A.
Published: April 2008

The New Zealand mud snail (NZMS) Potamopyrgus antipodarum is rapidly invading North American freshwaters, leading to speculation that native fisheries, especially those involving trout, will be negatively impacted. To assess whether trout would consume NZMSs and could assimilate nutrients from them, we conducted a laboratory 15N tracer study, a laboratory feeding study, and bioenergetics modeling with rainbow trout Oncorhynchus mykiss; we also evaluated 5 years of diet and condition data describing rainbow trout and brown trout Salmo trutta collected from a river colonized by NZMSs. The 15N tracer study showed that rainbow trout consumed and to a lesser extent assimilated NZMSs. Rainbow trout fed 15N-labeled NZMSs had muscle isotopic signatures that were 80% higher than those of fish fed unlabeled NZMSs and 30% lower than those of fish fed 15N-labeled amphipods. The feeding study showed that rainbow trout fed an exclusive and unlimited amount of NZMSs lost 0.14–0.48% of their initial body weight per day. Collection of rainbow trout feces showed that 8.5% of the NZMS shells were empty, and these snails were assumed to have been digested; 53.8% of NZMSs passed through the digestive system alive. Bioenergetics modeling showed that starved rainbow trout would have lost between 0.52% and 0.54% of their initial body weight per day, depending on their initial weight. Based on observed fish weight changes during three trial periods, mean modeled digestibility of NZMSs for rainbow trout fed an unlimited supply of the snails (proportion of maximum consumption = 1.0) was 63, 65, and 27%. Field survey data supported our laboratory experiments: we observed a sharp annual increase in the number of brown and rainbow trout consuming NZMSs between 2001 and 2005 in the Green River, Utah, downstream from Flaming Gorge Dam; moreover, the condition of brown and rainbow trout with NZMSs in their guts was significantly lower than that of fish without NZMSs in their stomachs. Our results confirm that North American trout fisheries face potential negative impacts from NZMS invasion.
Escaping the Surface: The Effect of Capture Depth on Submergence Success of Surface-Released Pacific Rockfish
Authors: Hannah Robert W. , Parker Steven J. , Matteson Keith M.
Published: April 2008

We evaluated the effect of capture depth and fish size on the ability of several Pacific rockfishes Sebastes spp. to resubmerge after hook-and-line capture and surface release. We observed fish as they were released into a bottomless floating enclosure, and we recorded submergence success within a 5-min time limit. Submergence success was greater than 80% for all rockfish captured in depths less than 30 m. Yellowtail rockfish S. flavidus (N = 51) were 100% successful at submerging in less than 49 s at all depths sampled (10–51 m). At capture depths of 40–51 m, submergence success was 89% for quillback rockfish S. maliger (N = 9), 65% for black rockfish S. melanops (N = 46), and 30% for canary rockfish S. pinniger (N = 40). At depths of 30–51 m, submergence success was 32% for blue rockfish S. mystinus (N = 31). The external signs of barotrauma (e.g., exopthalmia, eversion of the esophagus) increased with depth of capture and were least prevalent in yellowtail rockfish and quillback rockfish. The presence of severe esophageal eversion (beyond the buccal cavity) was strongly negatively associated with submergence success for several species (P < 0.01). At 40–51-m capture depths, the frequency of severe esophageal eversion by species was correlated with the frequency of submergence failure (P < 0.05). Logistic regression showed a negative relationship between depth of capture and submergence success for black rockfish (P < 0.001), blue rockfish (P < 0.001), and canary rockfish (P < 0.05). Larger body length negatively influenced submergence success only in blue rockfish (P < 0.05).
Modeling Variation in Mass‐Length Relations and Condition Indices of Lake Trout and Chinook Salmon in Lake Huron: A Hierarchical Bayesian Approach
Authors: He Ji X. , Bence James R. , Johnson James E. , Clapp David F. , Ebener Mark P.
Published: April 2008

Commonly used approaches to studying mass‐length relations and condition indices often do not adequately address covariance between mass‐length parameters, usually ignore heterogeneity in individual variance for body mass at a given length, and assume that length distributions of fish samples are similar across regions and years. We used body mass at selected lengths as condition indices based on statistical modeling and a hierarchical Bayesian approach to inferences, and our approach allowed us to avoid using restrictive assumptions. We estimated spatial and annual variation in mass‐length relations, where the process errors in parameters are drawn from a multivariate distribution. We also estimated region‐, year‐, and size‐group‐specific variance for individual variation in mass at given lengths. We applied our approach to study mass‐length relations of lake troutSalvelinus namaycush(1977‐2005) and Chinook salmonOncorhynchus tshawytscha(1983‐2004) in U.S. waters of Lake Huron. We found that small lake trout were able to maintain their condition in response to declines in prey availability, whereas Chinook salmon of the same size could not. Similarly, large Chinook salmon exhibited a greater and more rapid decline in body condition than did lake trout of the same size. We also found that spatial differences in recent temporal trends in condition of large fish altered the ranks of the three lake trout management regions. Ignoring spatial heterogeneity led to a biased overall average mass‐length relation for lake trout. The large temporal variation in mass‐length parameters suggested that it was better not to assume isometric growth for a specific year, even though the overall average exponent for Chinook salmon was nearly 3.0. In our study, conventional application of Fulton's condition factor to a relatively narrow size range was able to capture qualitative long‐term trends but missed some important short‐term changes because of the additional variation of length‐related bias and the limitation of sample sizes.
Effect of nitrate on the reduction of Reactive Red 2 by mesophilic anaerobic sludge
Authors: Dos Santos A. B. , Braúna C. H. C. , Mota S. , Cervantes F. J.
Published: April 2008

This research aimed to evaluate the effect of nitrate on anaerobic azo dye reduction by using mesophilic bioreactors, in the absence (reactor R2) and in the presence (reactor R1) of redox mediators. The azo dye Reactive Red 2 (RR2) and the redox mediator anthraquinone-2,6-disulphonate (AQDS) were selected as model compounds. The results showed that the bioreactors were efficient on RR2 reduction, in which ethanol showed to be a good electron donor to sustain dye reduction under anaerobic conditions. The redox mediator AQDS increased the rates of reductive decolourisation, but its effect was not so remarkable compared to the previous experiments conducted. Contrary to the raised hypothesis that the nitrate addition could decrease decolourisation rates and catalytic properties of the redox mediators, no effect of nitrate was observed in the bioreactors, suggesting that the presence of nitrate in textile wastewaters will not decrease the capacity of anaerobic reactors supplemented or not with redox mediators to decolourize azo dyes.
Partial stream digestion of residual municipal solid waste
Authors: De Baere L.
Published: April 2008

Anaerobic digestion of residual municipal solid waste (MSW) has become more important than the digestion of source separated biowaste. More than 52% of the capacity available in Europe was designed for digestion of residual municipal waste by the end of 2006, while this was only 13% in 1998. Partial digestion of residual waste organics, by which only a part of the organics is digested, has been implemented to reduce the need for dewatering and subsequent wastewater treatment. The digestate coming from part of the organics is immediately mixed with the non-digested organic fraction. This organic fraction is drier and still contains a lot of energy which can be used to dry the digestate during the aerobic composting of the mixture of digested and undigested organics. Such a MBT-plant has been operating for over a year whereby 2/3 of the organics (including sludge cake) are digested (25,000 t/year) and mixed after digestion with the remaining 1/3 of the organics. Biogas production averages 125.7 Nm2 per ton fed and contained 56.2% of methane. The mixture of digestate and non-digested organics is aerated in tunnels during 4 to 6 weeks. The stabilized endproduct is landfilled, meeting the stringent German standards for inert landfills. By using a dry fermentation able to produce a digestate at 35% solids, there is no need for dewatering the digestate so that no wastewater is produced.
Effect of protein on biohydrogen production from starch of food waste
Authors: Ding H. B. , Liu X. Y. , Stabnikova O. , Wang J.-Y.
Published: April 2008

This study demonstrated the influence of protein on biohydrogen production from carbohydrates, especially starch, by using different combinations of two model food wastes, rice as starch-rich and soybean residue as protein-rich food waste. It was found the maximum specific hydrogen production potential, 0.99 mol H2/mol initial starch as glucose, and the maximum specific hydrogen production rate, 530 ml H2/h g-VS, occurred at a starch/protein ratio of 1.7. The protein content in the initial food waste not only provided buffering capacity to neutralize the volatile fatty acids as concurrent products but also enhanced the hydrogen production by providing readily available organic nitrogen such as soluble proteins and amino acids to microorganisms.
The control of denitrification time in full scale by the automatic detection of the low nitrate bend in the redox curve
Authors: Cecil David
Published: April 2008

A practical problem with using redox potential to control nitrogen removal in activated sludge is detecting the bend in the redox curve that occurs when the nitrate concentration is reduced to low levels. In this paper, a method for detecting the bend is proposed. The method is based on fitting a third-order polynomial to the whole redox curve during a denitrification period. The bend is then the point of inflection on this curve. This is the potential when the second derivative of the polynomial is zero. The practical application of the method is demonstrated in full scale. The method successfully detected the bend in about 90% of aeration denitrification cycles. However, this method gave no significant improvement in nitrogen removal and less than 4% reduction in electricity consumption when compared with control based on a fixed redox set point. Therefore, it is recommended that a fixed set point be used, as this is a much simpler and more robust method.
Monitoring copper release in drinking water distribution systems
Authors: d'Antonio L. , Fabbricino M. , Panico A.
Published: April 2008

A new procedure, recently proposed for on-line monitoring of copper released from metal pipes in household plumbing system for drinking water distribution during the development of corrosion processes, is tested experimentally. Experiments were carried out in laboratory controlled conditions, using synthetic water and varying the water alkalinity. The possibility of using the corrosion potential as a surrogate measure of copper concentration in stagnating water is shown, verifying, in the meantime, the effect of alkalinity on the development of passivation phenomena, which tend to protect the pipe from corrosion processes. Experimental data are discussed, highlighting the potentiality of the procedure, and recognizing its limitations.
Standard signal processing using enriched sensor information for WWTP monitoring and control
Authors: Irizar I. , Alferes J. , Larrea L. , Ayesa E.
Published: April 2008

Important indicators for monitoring and control of wastewater treatment plants (WWTP) often have to be obtained from the processing of on-line signal trajectories. Therefore, the quality of sensor instantaneous measurements can be improved significantly if they are complemented with valuable information about the geometric features of their trajectories. The present paper describes the design and implementation of a Standard Signal Processing Architecture (SSPA) from which enriched sensor information is generated automatically. The SSPA has been made up of three complementary modules: the pre-processing module, the storage module and the post-processing module. Moreover, the SSPA has been parameterised so as to allow its adaptation to the specifications of every signal. By performing basic calculations on pre-processed signal trajectories, the storage module produces enriched vectors which collect information of the first and second time derivatives, average and variance values, peak values, linear regression parameters, curvature, etc. Then, the enriched information vectors can be exploited to implement customised monitoring and control tools. In this respect, the effectiveness of the SSPA has been demonstrated in three different practical cases: (1) OUR and KLa identification algorithms; (2) processing of measurements for real-time controllers; and, (3) detection of bend-points in on-line signals of SBR processes.
Wastewater modification processes assessment in a stabilization reservoir
Authors: Mannina G. , Mancini G. , Torregrossa M. , Viviani G.
Published: April 2008

A semi-empirical mechanistic model able to simulate the dynamics of a stabilization reservoir was developed incorporating both settling of particulate components and chemical/biological processes. Several factors affecting the reservoir effluent quality were taken into account: hydraulics and hydrology, solar radiation, atmospheric reaeration, algae, zooplankton, organic matter, pathogen bacteria, and sediment-water interaction. The model quantifies the specific influence of each factor on effluent quality, evaluating the correlation between the different considered factors. State variables included in the model were: algae, dissolved oxygen, organic matter, zooplankton and indicator bacteria.

The model was transferred into a computational code in order to provide a useful and versatile tool for water resource planning management issues. The model was verified by comparing simulated results with full-scale data collected from a small reservoir (Sicily, IT) filled with partially treated wastewater. The reservoir has a volume of 11,000 m3, a maximum depth of 6.3 m and a mean depth of about 5 m. The monitoring period lasted four months during which the reservoir operated in different hydraulics conditions: as a standard batch reactor and as a continuous flow reactor. The model was able to reproduce the behaviour of the principal simulated parameters thus representing a potential tool for the management and performance optimization of these peculiar storage/treatment systems.
Reactive tracers reveal hydraulic and control instabilities in full-scale activated sludge plant
Authors: Braun D. , Gujer W.
Published: April 2008

The hydraulic characteristics of aeration tanks in WWTPs have a major impact on the degradation of pollutants, as well as on the control of the aeration. In particular in long reactors, which are not separated by baffles, hydraulic shortcuts or large scale recirculation can lead to a loss of performance. This work demonstrates that reactive tracers such as ammonium and oxygen can be used to investigate the hydraulics of aeration tanks in detail. With the use of electrochemical sensors it is possible to investigate effects in a broad range of time scales.

In the present case study a slow oscillation of the aeration control loop was investigated. Large scale recirculation in the aeration tank and fast fluctuations of the ammonium concentrations close to the oxygen sensor were identified as the cause of these oscillations. Both, the recirculation as well as the fluctuation of the ammonium have a substantial influence on the performance of the aeration tank and the aeration control loop.
Exposure and risk assessment of Salmonella in recycled residuals
Authors: Gerba Charles P. , Castro-del Campo Nohelia , Brooks John P. , Pepper Ian L.
Published: April 2008

The potential health effects of Salmonella found in wastewater residuals is dependent on the exposure of individuals to the organism. This paper provides a risk assessment for human infection from Salmonella due to direct contact with Class B biosolids, and from contact with Class A biosolids following regrowth of Salmonella. In addition, a risk assessment is provided for infection via airborne transport of bioaerosols from Class B biosolids and biosolids in which regrowth had occurred, to off-site communities. Results of the risk characterization imply that the risk of human infection from direct contact with Class B land applied residuals and subsequent ingestion is low. In contrast, the risk from direct contact with Class A residuals following regrowth is greater. Risks from airborne transport of Salmonella via bioaerosols away from a Class B land application site are also low. However, once again the risk from aerosols resulting from biosolids in which regrowth had occurred was greater. Based on these analyses, we conclude that it is highly unlikely that Salmonella infections will occur from land applied Class A or B residuals. However, risks become significant if Class A biosolids are stored anaerobically i.e. saturated, prior to land application.
Technical and economical evaluation of water recycling in the carwash industry with membrane processes
Authors: Boussu K. , Van Baelen G. , Colen W. , Eelen D. , Vanassche S. , Vandecasteele C. , Van der Bruggen B.
Published: April 2008

In the carwash industry, water recycling is necessary to be in accordance with present and upcoming environmental laws. As this is not possible with traditional techniques, membrane processes (like ultrafiltration (UF) and nanofiltration (NF)) are technically and economically evaluated in this study. Concerning the technical part, there needs to be a compromise between a high permeate permeability on the one hand and a high permeate purity on the other hand. Depending on the use of the purified wastewater, ultrafiltration (to recycle wastewater in the main wash cycle) or nanofiltration (to recycle wastewater in the rinsing step) would be the optimal choice. Concerning the financial part, the implementation of membrane processes in the wastewater purification installation is economically feasible, especially when expensive tap water is used as pure water. These positive evaluations imply that membrane processes can be useful to recycle wastewater in the carwash industry, on condition that the right membrane type (with the least membrane fouling) and the right process format (e.g., hybrid process of UF and/or NF with a biological treatment) is selected.
Cranial Vault Defects: The Description of Three Cases that Illustrate a Spectrum of Anomalies
Authors: Evans Clair , Marton Tamas , Rutter Susan , Anumba Dilly O. , Whitby Elspeth H. , Cohen Marta C.
Published: April 2008

Three cases of cranial vault defects in fetuses are described. All 3 cases underwent postmortem examination, and in 2 of them postmortem magnetic resonance imaging was also performed. The phenotypical differences between the cases illustrate a spectrum of cranial vault defects, associated anomalies, and pathogenic mechanisms involved in the etiology of this rare malformation. All 3 cases were male, and the cranial vault defects corresponded to exencephaly with acrania/acalvaria caused by amniotic band syndrome, acalvaria, and acrania presenting in a chorangiopagus parasiticus twin.
Preventing Film Blocking and Optimizing Haze of Metallocene PE Blown Films Through Blending with Rigid Polymers
Authors: Chinsirikul W. , Fuongfuchat A. , Kerddonfag N. , Phiboonkulsumrit S. , Winotapun C. , Khumsang P.
Published: April 2008

Film blocking typically observed in both mPE and higher modulus mPE/PP blends could be effectively reduced or prevented through the incorporation of only 2 wt.-% of rigid PS or PMMA into the blends. Blocking forces required to separate the two adjacent layers of mPE/[PP/PS] and mPE/[PP/PMMA] films were significantly reduced from 20.9 g for the neat mPE, to 0 g and 10.8 g, respectively. Films containing rigid PS, however, possessed high haze of 32.37 % while a much lower haze of 10.88 % was obtained for films with PMMA. Based on atomic force microscopy (AFM) results, total haze increased systematically with an increase in RMS surface roughness. Nevertheless, there seemed to be a critical surface roughness that could give rise to both low film blocking and low optical haze, as found in the mPE/[PP/PMMA] films. All developed films also had suitable mechanical properties and high oxygen transmission rates, OTR (> 10 000 cm3/m2 day); these high OTR films are desirable for fresh produce packaging. Current findings also demonstrate that controlling film morphologies of these mPE blends with PS and PMMA through mixing and processing principles appears to be a promising route in determining surface roughness and internal structure that have direct influences on film blocking and clarity or haze.
Development of Bicomponent Spunbond Nonwoven Webs Consisting of Ultra-fine Splitted Fibers
Authors: Prahsarn C. , Matsubara A. , Motomura S. , Kikutani T.
Published: April 2008

Development of bicomponent spunbond nonwoven consisting of ultra-fine splitted polypropylene (PP) and polyethylene (PE) fibers was described. The morphological structures developed in bicomponent spinning of PP/PE fibers with the cross-sectional configuration of “sixteen-segment hollow pie” were investigated in relation to molecular properties as well as the resulting fiber splittability. Structure developed in each component in the melt spinning process was found to depend not only on its molecular properties but also on those of the other component. Results showed that the PP/PE pair exhibiting good splittability possesses high molecular orientation in both components.
Erosive Wear Assesment of Glass Reinforced Polyester-Flyash Composites Using Taguchi Method
Authors: Patnaik A. , Satapathy A. , Mahapatra S. S. , Dash R. R.
Published: April 2008

Experiments are conducted to study the solid particle erosion wear behavior of glass reinforced polyester composites with flyash as a filler material. This study makes use of a methodology based on Taguchi's experimental design approach to characterize the erosion response of these composites. The procedure eliminates the need for repeated experiments and thus saves time, materials and cost. It identifies not only the significant control factors but also their interactions influencing the erosion rate predominantly. From the experimental findings an optimal combination of control factors is obtained on the basis of a proposed predictive model. This model is validated by performing a confirmation experiment with an arbitrarily chosen set of factor combination. Finally, optimal factor settings for minimum wear rate under specified experimental conditions have been determined using genetic algorithm.
An Experimental Study on the Pickout of Scaled-up Gravure Cells
Authors: Chuang H.-K. , Lee C.-C. , Liu T.-J.
Published: April 2008

An experimental study was carried out to investigate the pickout of scaled-up gravure cells. The pickout of a gravure cell is defined as the fractional volume of the coating solution transferred from the cell to the moving roller. Gravure cells of different sizes and combinations were examined. Dilute poly(vinyl) alcohol solutions was used as test fluids.

It was found that the stability of the liquid bridge that connects the moving roller and the gravure cell is the most critical factor to determine the pickout. The most stable condition that yields the maximum pickout is that the moving roller just touches the gravure cell and the coating gap is zero. Either a positive or a negative coating gap will decrease the pickout.

The pickout for a small gravure cell is lower than a larger one because the liquid bridge is less stable. The experiment on different cell combinations reveals that if the number of gravure cells in the coating direction is increased, the average pickout per cell will drop. The pickout decreases as the capillary number increases. A universal correlation was found between the modified pickout and the capillary number. This modified pickout is the product of the pickout and a shift factor which involves all the geometric parameters in gravure cells.
Spatial scale of GIS‐derived categorical variables affects their ability to separate sites by community composition
Authors: Holt Emily A. , McCune Bruce , Neitlich Peter
Published: April 2008

Questions: How well do GIS‐derived categorical variables (e.g., vegetation, soils, geology, elevation, geography, and physiography) separate plots based on community composition? How does the ability to distinguish plots by community composition vary with spatial scale, specifically number of patch types, patch size and spatial correlation? Both these questions bear on the effective use of stratifying variables in landscape ecology.

Location: Arctic tundra; Bering Land Bridge National Preserve, northwestern Alaska, USA.

Methods: We evaluated the strength of numerous alternative stratifying variables using the multi‐response permutation procedure (MRPP). We also created groups based on lichen community composition, using cluster analyses, and evaluated the relationship between these groups and groupings within categorical variables using Mantel tests. Each test represents different measures of community separation, which were then evaluated with respect to each variable's spatial characteristics.

Results: We found each categorical variable derived from GIS separated lichen communities to some degree. Separation success ranged from strong (Alaska Subsections) to weak (Watersheds and Reindeer Ownership). Lichen community groups derived from cluster analysis demonstrated statistically significant relationships with 13 of the 17 categorical variables. Partialling out effects of spatial distance had little effect on these relationships.

Conclusions: Greater number of patch types and larger average patch sizes contribute to optimal success in separating lichen communities; geographic distance did not appear to significantly alter separation success. Group distinctiveness or strength increased with more patch types or groups. Alternatively, congruence between lichen community types derived from cluster analysis and the 17 categorical variables was inversely related to patch size and spatial correlation.
Culture and the socialization of child cardiovascular regulation at school entry in the US
Authors: Decaro Jason A. , Worthman Carol M.
Published: April 2008

The measurement of cardiovascular functioning targets an important bridge between social conditions and differential well‐being. Nevertheless, the biocultural, psychosocial processes that link human ecology to cardiovascular function in children remain inadequately characterized. Childrearing practices shaped by parents' cultural beliefs should moderate children's affective responses to daily experience, and hence their psychophysiology. The present study concerns interactions among family ecology, the normative social challenge of entry into kindergarten, and parasympathetic (vagal) cardiac regulation in US middle‐class children (N= 30). Although parents believed children must be protected from overscheduling to reduce stress and improve socio‐emotional adaptation, maternal rather than child schedules predicted parasympathetic regulation during a nonthreatening social engagement task following school entry. Children of busier married mothers, but less busy single mothers, showed the context‐appropriate pattern of parasympathetic regulation, low respiratory sinus arrhythmia (RSA). These findings are expected if: maternal and family functioning, rather than the scheduling of the child's daily life, principally drive young children's cardiovascular responsiveness to a normative challenge; and busy schedules represent high family functioning with married mothers, but not under single‐parent conditions wherein adult staffing is uniquely constrained. Family ecology is shaped by culture, and in turn shapes the development of children's cardiovascular responses. Appropriately fine‐grained analysis of daily experience can illustrate how culturally driven parenting practices may have unintended consequences for child biological outcomes that vary by family structure. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.
Dendrimer‐encapsulated Pt nanoparticles/polyaniline nanofibers for glucose detection
Authors: Xu Lihuan , Zhu Yihua , Tang Longhua , Yang Xiaoling , Li Chunzhong
Published: April 2008

A novel amperometric glucose biosensor based on self‐assembling glucose oxidase (GOx) and dendrimer‐encapsulated Pt nanoparticles (Pt‐DENs) on nanofibrous polyaniline (PANI) was described. PANI nanofibers were synthesized via an interfacial polymerization method. A sulfonated polyelectrolytes‐poly(sodium 4‐styrenesulfonate) (PSS) was used to form the negative PANI/sulfonated polyelectrolyte complex, which had good disperse in aqueous solution. GOx was immobilized on the PANI/PSS surface by alternatively assembling a cationic Pt‐DENs layer and an anionic GOx layer. The unique sandwich‐like layer structure (Pt‐DENs/GOx/Pt‐DENs/PANI/PSS) formed by self‐assembling provides a favorable microenvironment to keep the bioactivity of GOx and to prevent enzyme molecule leakage. The fabricated Pt‐DENs/GOx/Pt‐DENs/PANI/PSS electrode exhibited excellent response performance to glucose with a detection limit of 0.5 μM, wide linear range from 10 μM to 4.5 mM, short response time within 5 s, improved sensitivity of 39.63 μA/(mM cm2), and good stability (85% remains after 20 days). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
3D‐QSAR Studies on Chromone Derivatives as HIV‐1 Protease Inhibitors: Application of Molecular Field Analysis
Authors: Nunthanavanit Patcharawee , Anthony Nahoum G. , Johnston Blair F. , Mackay Simon P. , Ungwitayatorn Jiraporn
Published: April 2008

Three‐dimensional quantitative structure‐activity relationship (3D‐QSAR) models were developed for chromone derivatives against HIV‐1 protease using molecular field analysis (MFA) with genetic partial least square algorithms (G/PLS). Three different alignment methods: field fit, pharmacophore‐based, and receptor‐based were used to derive three MFA models. All models produced good predictive ability with high cross‐validated r2(r2cv), conventional r2, and predictive r2(r2pred) values. The receptor‐based MFA showed the best statistical results with r2cv= 0.789, r2= 0.886, and r2pred= 0.995. The result obtained from the receptor‐based model was compared with the docking simulation of the most active compound21in this chromone series to the binding pocket of HIV‐1 protease (PDB entry 1AJX). It was shown that the MFA model related well with the binding structure of the complex and can provide guidelines to design more potent HIV‐1 protease inhibitors.
Functional characterization of hypertrophy in chondrogenesis of human mesenchymal stem cells
Authors: Mueller Michael B. , Tuan Rocky S.
Published: April 2008

Objective

Mesenchymal stem cells (MSCs) are promising candidate cells for cartilage tissue engineering. Expression of cartilage hypertrophy markers (e.g., type X collagen) by MSCs undergoing chondrogenesis raises concern for a tissue engineering application for MSCs, because hypertrophy would result in apoptosis and ossification. To analyze the biologic basis of MSC hypertrophy, we examined the response of chondrifying MSCs to culture conditions known to influence chondrocyte hypertrophy, using an array of hypertrophy‐associated markers.

Methods

Human MSC pellet cultures were predifferentiated for 2 weeks in a chondrogenic medium, and hypertrophy was induced by withdrawing transforming growth factor β (TGFβ), reducing the concentration of dexamethasone, and adding thyroid hormone (T3). Cultures were characterized by histologic, immunohistochemical, and biochemical methods, and gene expression was assessed using quantitative reverse transcription–polymerase chain reaction.

Results

The combination of TGFβ withdrawal, a reduction in the level of dexamethasone, and the addition of T3 was essential for hypertrophy induction. Cytomorphologic changes were accompanied by increased alkaline phosphatase activity, matrix mineralization, and changes in various markers of hypertrophy, including type X collagen, fibroblast growth factor receptors 1–3, parathyroid hormone–related protein receptor, retinoic acid receptor γ, matrix metalloproteinase 13, Indian hedgehog, osteocalcin, and the proapoptotic gene p53. However, hypertrophy was not induced uniformly throughout the pellet culture, and distinct regions of dedifferentiation were observed.

Conclusion

Chondrogenically differentiating MSCs behave in a manner functionally similar to that of growth plate chondrocytes, expressing a very similar hypertrophic phenotype. Under the in vitro culture conditions used here, MSC‐derived chondrocytes underwent a differentiation program analogous to that observed during endochondral embryonic skeletal development, with the potential for terminal differentiation. This culture system is applicable for the screening of hypertrophy‐inhibitory conditions and agents that may be useful to enhance MSC performance in cartilage tissue engineering.
Reciprocal cross‐talk between RANKL and interferon‐γ–inducible protein 10 is responsible for bone‐erosive experimental arthritis
Authors: Kwak Han Bok , Ha Hyunil , Kim Ha‐Neui , Lee Jong‐Ho , Kim Hun Soo , Lee Seungbok , Kim Hyun‐Man , Kim Jung Yeon , Kim Hong‐Hee , Song Yeong Wook , Lee Zang Hee
Published: April 2008

Objective

Interferon‐γ–inducible protein 10 (IP‐10; also called CXCL10), a chemokine important in the migration and proliferation of T cells, is induced in a wide variety of cell types. However, the role of IP‐10 in rheumatoid arthritis (RA) remains largely unknown. The purpose of this study was to examine the potential role of IP‐10 in bone resorption and RA through examination of a mouse model of collagen‐induced arthritis (CIA).

Methods

The effects of IP‐10 on mouse T cells during osteoclast differentiation were examined in migration assays. The bone‐erosive activity of IP‐10 was determined in vivo in a mouse model of CIA by histologic and immunostaining analyses. Cytokine levels in serum and culture medium were measured with sandwich enzyme‐linked immunosorbent assays.

Results

Serum concentrations of IP‐10 were significantly higher in mice with CIA than in control mice. RANKL greatly induced IP‐10 expression in osteoclast precursors, but not in mature osteoclasts. IP‐10 stimulated the expression of RANKL and tumor necrosis factor α (TNFα) in CD4+ T cells and induced osteoclastogenesis in cocultures of CD4+ T cells and osteoclast precursors. However, IP‐10 did not induce RANKL or TNFα in CD8+ T cells. Treatment with neutralizing antibody to IP‐10 significantly inhibited the infiltration of CD4+ T cells and F4/80+ macrophages into the synovium and attenuated bone destruction in mice with CIA. Furthermore, levels of RANKL and TNFα were inhibited by antibody to IP‐10. Bone erosion was observed in mice infected with an IP‐10 retrovirus.

Conclusion

Our findings suggest that IP‐10 plays a critical role in the infiltration of CD4+ T cells and F4/80+ macrophages into inflamed joints and causes bone destruction. Our results provide the first evidence that IP‐10 contributes to the recruitment of inflammatory cells and is involved in bone erosion in inflamed joints.
Autoantibody prevalence and lupus characteristics in a unique African American population
Authors: Kamen Diane L. , Barron Mia , Parker Tia M. , Shaftman Stephanie R. , Bruner Gail R. , Aberle Teresa , James Judith A. , Scofield R. Hal , Harley John B. , Gilkeson Gary S.
Published: April 2008

Objective

The Gullah population of the Sea Islands of South Carolina is a unique group of African Americans who, due to geographic and cultural factors, remained isolated with minimal genetic admixture until the 1950s. Because of the unique homogeneous nature of the Gullah, we sought to define the genetic and environmental factors contributing to systemic lupus erythematosus (SLE) in this population.

Methods

Using data from our ongoing cohort study of lupus in the Gullah population, which we established in 2003, disease characteristics and serologic profiles were summarized for 184 patients with SLE, 144 unaffected first‐degree relatives, and 144 matched unrelated, unaffected control subjects. These findings were compared with those in 2 other large cohorts of African Americans with SLE.

Results

In the Gullah cohort, we observed a high prevalence of SLE multiplex families (26.6%), malar rash (56.0%), discoid rash (34.2%), photosensitivity (60.9%), and oral/nasal ulcerations (43.5%), but a lower prevalence of hematologic and pleuropericardial disease than has been reported in other African American cohorts. Overall renal and central nervous system involvement, number of American College of Rheumatology disease criteria met, and SLE Damage Index scores were similar to those reported in other cohorts. Of interest, male and female first‐degree relatives and male and female control subjects in this cohort had similar rates of antinuclear antibody positivity, whereas lupus‐specific antibodies were more prevalent in the women than in the men.

Conclusion

These data indicate that the severity of lupus in the Gullah population is similar to that in other African American populations, whereas skin disease and familial disease prevalence are increased in the Gullah. These findings suggest that there is an increased genetic influence on overall disease in this cohort compared with that in other African American cohorts, which confirms the unique nature of this cohort.
Denosumab treatment effects on structural damage, bone mineral density, and bone turnover in rheumatoid arthritis: A twelve‐month, multicenter, randomized, double‐blind, placebo‐controlled, phase II clinical trial
Authors: Cohen Stanley B. , Dore Robin K. , Lane Nancy E. , Ory Peter A. , Peterfy Charles G. , Sharp John T. , van der Heijde Désirée , Zhou Lifen , Tsuji Wayne , Newmark Richard ,   Denosumab Rheumatoid Arthritis Study Group
Published: April 2008

Objective

RANKL is essential for osteoclast development, activation, and survival. Denosumab is a fully human monoclonal IgG2 antibody that binds RANKL, inhibiting its activity. The aim of this multicenter, randomized, double‐blind, placebo‐controlled, phase II study was to evaluate the effects of denosumab on structural damage in patients with rheumatoid arthritis (RA) receiving methotrexate treatment.

Methods

RA patients received subcutaneous placebo (n = 75), denosumab 60 mg (n = 71), or denosumab 180 mg (n = 72) injections every 6 months for 12 months. The primary end point was the change from baseline in the magnetic resonance imaging (MRI) erosion score at 6 months.

Results

At 6 months, the increase in the MRI erosion score from baseline was lower in the 60‐mg denosumab group (mean change 0.13; P = 0.118) and significantly lower in the 180‐mg denosumab group (mean change 0.06; P = 0.007) than in the placebo group (mean change 1.75). A significant difference in the modified Sharp erosion score was observed as early as 6 months in the 180‐mg denosumab group (P = 0.019) as compared with placebo, and at 12 months, both the 60‐mg (P = 0.012) and the 180‐mg (P = 0.007) denosumab groups were significantly different from the placebo group. Denosumab caused sustained suppression of markers of bone turnover. There was no evidence of an effect of denosumab on joint space narrowing or on measures of RA disease activity. Rates of adverse events were comparable between the denosumab and placebo groups.

Conclusion

Addition of twice‐yearly injections of denosumab to ongoing methotrexate treatment inhibited structural damage in patients with RA for up to 12 months, with no increase in the rates of adverse events as compared with placebo.
Safety and efficacy of up to eight years of continuous etanercept therapy in patients with juvenile rheumatoid arthritis
Authors: Lovell Daniel J. , Reiff Andreas , Ilowite Norman T. , Wallace Carol A. , Chon Yun , Lin Shao‐Lee , Baumgartner Scott W. , Giannini Edward H. ,   Pediatric Rheumatology Collaborative Study Group
Published: April 2008

Objective

To evaluate the safety and efficacy of up to 8 years of etanercept treatment in patients with polyarticular‐course juvenile rheumatoid arthritis (JRA).

Methods

Patients with JRA who previously participated in a randomized controlled trial (RCT) of etanercept were eligible to receive etanercept in a long‐term open‐label extension (OLE) trial. Safety end points included the incidences of serious adverse events (SAEs), medically important infections (MIIs), and death. Efficacy end points included the American College of Rheumatology (ACR) Pediatric 30 (Pedi 30), Pedi 50, Pedi 70, Pedi 90, and Pedi 100 criteria for improvement.

Results

Of the 69 patients originally enrolled in the RCT, 58 (84%) participated in the OLE, for a total of 318 patient‐years of etanercept exposure. A total of 42 of the 58 patients (72%) entered the fourth year of continuous etanercept treatment, and 26 patients (45%) entered the eighth year. Sixteen patients (23% of those entering the RCT) reported 39 SAEs. The overall rate of SAEs (0.12 per patient‐year) did not increase with long‐term exposure to etanercept. The rate of MIIs (0.03 per patient‐year) remained low; 1 new MII was reported in patients with ≥5 years of etanercept exposure. No cases of tuberculosis, opportunistic infections, malignancies, lymphomas, lupus, demyelinating disorders, or deaths were reported. An ACR Pedi 70 response or higher was achieved by 100% of patients with 8 years of data (11 of 11) and by 61% of patients according to the last observation carried forward data (28 of 46).

Conclusion

These data suggest that the acceptable safety profile of etanercept therapy is maintained for up to 8 years in this population of JRA patients. Improvements in the signs and symptoms of JRA were also maintained for up to 8 years.
The shared epitope hypothesis in rheumatoid arthritis: Evaluation of alternative classification criteria in a large UK Caucasian cohort
Authors: Morgan Ann W. , Haroon‐Rashid Lubna , Martin Stephen G. , Gooi Hock‐Chye , Worthington Jane , Thomson Wendy , Barrett Jennifer H. , Emery Paul
Published: April 2008

Objective

Many classification systems for the HLA–DRB1 allelic association with rheumatoid arthritis (RA) have been reported, but few have been validated in additional populations. We sought to evaluate 3 different DRB1 allele classification systems in a large cohort of Caucasian RA patients and control subjects in the UK.

Methods

HLA–DRB1 typing was undertaken in 1,325 Caucasian RA patients and 462 healthy Caucasian controls who were residents of the UK. Logistic regression analyses were performed to investigate the different classification systems.

Results

We confirmed the association between the susceptibility alleles S2 and S3P, as proposed by Tezenas du Montcel, and the presence of RA in UK Caucasians. A significant hierarchy of risk was observed within the S3P allele group. There was no evidence of a significant association between DRB1*1001 and RA. Our data did not support the hypothesis that an isoleucine at position 67 conferred protection against RA, other than in contrast to the susceptibility alleles. However, the presence of an aspartic acid at amino acid 70 did appear to confer some degree of protection.

Conclusion

We were unable to fully substantiate any of the 3 recent revisions of the shared epitope hypothesis in this large cohort of Caucasian RA patients and control subjects in the UK. This reinforces the importance of evaluating disease susceptibility alleles in different Caucasian populations as well as in other ethnic groups. In particular, it will be important to clarify the precise DRB1 association in a given population before DRB1 genotyping is incorporated into clinical diagnostic or treatment algorithms.
Profound and paradoxical impact on arthritis and autoimmunity of the rat antigen‐presenting lectin‐like receptor complex
Authors: Guo Jian Ping , Bäckdahl Liselotte , Marta Monica , Mathsson Linda , Rönnelid Johan , Lorentzen Johnny C.
Published: April 2008

Objective

The antigen‐presenting lectin‐like receptor complex (APLEC) was recently identified as a genetic determinant for arthritis susceptibility. We undertook this study to define mechanisms underlying the impact of APLEC on arthritis, to determine whether sex effects occur, and to determine whether APLEC influences different types of arthritis and phenotypes other than susceptibility.

Methods

Arthritis‐susceptible DA rats were compared with sex‐matched congenic rats in which APLEC alleles were substituted with alleles from arthritis‐resistant PVG rats. Six different arthritogenic agents were injected at the base of the tail: Freund's incomplete adjuvant, pristane, squalene, killed mycobacteria, yeast β‐glucan, or rat type II collagen (CII). Arthritis was visually scored, body weight was measured, and anti‐CII IgG and cytokine messenger RNA (mRNA) levels were determined by enzyme‐linked immunosorbent assay and reverse transcription–polymerase chain reaction, respectively.

Results

In 5 models of rheumatoid arthritis (RA), congenic rats deviated profoundly from DA rats by having reduced arthritis susceptibility, delayed onset, decreased severity, and/or reduced body weight loss. Paradoxical opposite genetic effects were noted, including a more severe disease course in congenic males in pristane‐induced arthritis and decreased clinical signs in collagen‐induced arthritis despite increased autoantibody levels. Interestingly, the anti‐CII IgG isotype profile was skewed in congenic rats, and markedly reduced lymph node mRNA levels for interleukin‐17 suggested that the cytokine profile of autoreactive T helper cells was also skewed in a less pathogenic direction.

Conclusion

Rat APLEC regulates autoimmunity and multiple phenotypes in several types of arthritis. However, delineating the genetic impact may require stratification for sex or mode of arthritis induction. This pathogenetic complexity should be considered when evaluating APLEC in inflammatory and autoimmune diseases, including RA.