bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atrazine does not affect algal biomass or snail populations in microcosm communities at environmentally relevant concentrations
Authors: Baxter Leilan R , Moore Dana L , Sibley Paul K , Solomon Keith R , Hanson Mark L 
Published: April 2011

Abstract
The herbicide atrazine is a photosynthetic inhibitor used around the world in agricultural applications. Contamination of surface waters adjacent to treated areas can directly reduce growth of nontarget aquatic autotrophs, but the severity of impacts is highly dependent on species sensitivity and exposure concentration. Secondary effects resulting from macrophyte or phytoplankton decline may include an expansion of the more tolerant periphyton community. Recently, this shift in the autotrophic community has been proposed as a mechanism for increased rates of parasite infections in amphibians via augmented populations of aquatic snails which act as intermediate hosts to larval trematodes. To further clarify this relationship, an outdoor microcosm study was conducted to examine the effects of atrazine on primary production and snail populations over a range of environmentally relevant concentrations. In July 2009, 15 experimental ponds were treated to achieve initial concentrations of 0, 1, 10, 30, and 100 µg/L atrazine. Over a period of 73 d, measures were taken of macrophyte, phytoplankton, and periphyton biomass, growth, and fecundity of caged snails (Physella spp. and Stagnicola elodes) and free-living snails (Physella spp.). Except for declines in macrophyte biomass at the highest treatment level, no consistent relationships were found between atrazine concentration and any measured parameter. Comparison of these results with previous findings highlights the variability of responses to atrazine exposure between similarly constructed freshwater communities, even at concentrations up to 20 times higher than sustained environmental levels. Environ. Toxicol. Chem. 2011; 30:1689–1696. © 2011 SETAC
Selected pesticides adsorption and desorption in substrates from artificial wetland and forest buffer
Authors: Passeport Elodie , Benoit Pierre , Bergheaud Valérie , Coquet Yves , Tournebize Julien 
Published: April 2011

Abstract
Buffer zones such as artificial wetlands and forest buffers may help decrease non–point-source pesticide pollution from agricultural catchments. The present study focuses on understanding the role of the substrates mainly found in such buffer zones for pesticide adsorption and desorption. Radiolabeled [14C]isoproturon, [14C]metazachlor, and [14C]epoxiconazole were used to measure adsorption and desorption isotherms on wetland sediments and plants and forest soil and litter from two sites in France. Wetland sediments and forest soil exhibited the most important potential for pesticide adsorption. Wetland plants and forest litter also showed high adsorption coefficients and were associated with highly hysteretic desorption, particularly for the moderately mobile isoproturon and metazachlor. Adsorption of the highly hydrophobic epoxiconazole was strong and associated with weak desorption from all substrates. Calculated sorption coefficients were larger than those classically measured on soils. Isoproturon, metazachlor, and epoxiconazole KOC sorption coefficients ranged from 84 to 372, 131 to 255, and 1,356 to 3,939 L/kg, respectively. Therefore, specifically collecting buffer zone substrate sorption data is needed for modeling purposes. Results showed that forests and wetlands present potential for pesticide retention. This may be enhanced by planting vegetation and leaving dead vegetal material in buffer zone design. Environ. Toxicol. Chem. 2011; 30:1669–1676. © 2011 SETAC
A note on the performance of regime switching hedge strategy
Authors: Lien Donald 
Published: April 2011

AbstractWe characterize conditions under which the regime switching (RS) hedge strategy will perform better than the ordinary least squares (OLS) hedge strategy. The result can be extended to the case where the GARCH effects prevail. Specifically, these conditions would allow the RS‐GARCH hedge strategy to dominate both OLS and GARCH hedge strategies. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark
Head direction cells in the postsubiculum do not show replay of prior waking sequences during sleep
Authors: Brandon Mark P. , Bogaard Andrew R. , Andrews Chris M. , Hasselmo Michael E. 
Published: April 2011

AbstractDuring slow‐wave sleep (SWS) and rapid eye movement (REM) sleep, hippocampal place cells in the rat show replay of sequences previously observed during waking. We tested the hypothesis from computational modeling that the temporal structure of REM sleep replay could arise from an interplay of place cells with head direction cells in the postsubiculum. Physiological single‐unit recording was performed simultaneously from five or more head direction or place by head direction cells in the postsubiculum during running on a circular track allowing sampling of a full range of head directions, and during sleep periods before and after running on the circular track. Data analysis compared the spiking activity during individual REM periods with waking as in previous analysis procedures for REM sleep. We also used a new procedure comparing groups of similar runs during waking with REM sleep periods. There was no consistent evidence for a statistically significant correlation of the temporal structure of spiking during REM sleep with spiking during waking running periods. Thus, the spiking activity of head direction cells during REM sleep does not show replay of head direction cell activity occurring during a previous waking period of running on the task. In addition, we compared the spiking of postsubiculum neurons during hippocampal sharp wave ripple events. We show that head direction cells are not activated during sharp wave ripples, whereas neurons responsive to place in the postsubiculum show reliable spiking at ripple events. © 2011 Wiley Periodicals, Inc.
Folate‐conjugated amphiphilic star‐shaped block copolymers as targeted nanocarriers
Authors: Zhu Jundong , Zhou Zhichao , Yang Cuihong , Kong Deling , Wan Ying , Wang Zheng 
Published: April 2011

AbstractFolate (FA)‐conjugated star‐shaped copolymer was prepared as a targeted carrier for anticancer drug delivery by ring‐opening polymerization of L‐lactide using pentaerythritol (PTL) as an initiator, followed by conjugation with methoxy poly(ethylene glycol) (MPEG) and FA‐poly(ethylene glycol) (FA‐PEG). The resulting amphiphilic star‐shaped copolymer was shaped into drug‐loaded micelles, and the achieved micelles had an average size of around 146 nm in diameter. It was found that the sustained release time of model drug (indomethacin, IMC) from some selected micelles could reach around 40 h. In comparison with linear poly(L‐lactic acid)‐block‐methoxy poly(ethylene glycol) copolymer (PLA‐MPEG), the stability of the star‐shaped pentaerythritol‐co‐poly(L‐lactic acid)‐block‐[methoxy poly(ethylene glycol) and FA‐poly(ethylene glycol)] (PTL‐PLA‐MPEG/PEG‐FA) micelle was significantly improved because of the lower critical micelle concentration (CMC). The specificity of PTL‐PLA‐MPEG/PEG‐FA targeting cancer cells was demonstrated by intracellular uptake of PTL‐PLA‐MPEG/PEG‐FA and PTL‐PLA‐MPEG using HeLa human cervical cancer cells. After 2 h in vitro incubation, a significant intracellular uptake for PTL‐PLA‐MPEG/PEG‐FA over PTL‐PLA‐MPEG was observed by using inverted fluorescence microscope and flow cytometry. These results suggested that PTL‐PLA‐MPEG/PEG‐FA polymeric micelle could be a potentially useful carrier for delivering selected drugs to FA‐receptor positive cancer cells. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Biological performance of a novel biodegradable polyamidoamine hydrogel as guide for peripheral nerve regeneration
Authors: Magnaghi Valerio , Conte Vincenzo , Procacci Patrizia , Pivato Giorgio , Cortese Paolo , Cavalli Erika , Pajardi Giorgio , Ranucci Elisabetta , Fenili Fabio , Manfredi Amedea , Ferruti Paolo 
Published: April 2011

AbstractPolyamidoamines (PAAs) are a well‐known family of synthetic biocompatible and biodegradable polymers, which can be prepared as soft hydrogels characterized by low interfacial tension and tunable elasticity. For the first time we report here on the in vivo performance of a PAA hydrogel implant as scaffold for tissue engineering. In particular, an amphoteric agmatine‐deriving PAA hydrogel shaped as small tubing was obtained by radical polymerization of a soluble functional oligomeric precursor and used as conduit for nerve regeneration in a rat sciatic nerve cut model. The animals were analyzed at 30, 90, and 180 days post‐surgery. PAA tubing proved to facilitate nerve regeneration. Good surgical outcomes were achieved with no signs of inflammation or neuroma. Moreover, nerve regeneration was morphologically sound and the quality of functional recovery satisfactory. In conclusion, PAA hydrogel scaffolds may represent a novel and promising material for peripheral nerve regeneration. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Cancellous bone formation response to simulated resistance training during disuse is blunted by concurrent alendronate treatment
Authors: Swift Joshua M , Swift Sibyl N , Nilsson Mats I , Hogan Harry A , Bouse Scott D , Bloomfield Susan A 
Published: April 2011

Abstract
The purpose of this study was to assess the effectiveness of simulated resistance training (SRT) exercise combined with alendronate (ALEN) in mitigating or preventing disuse-associated losses in cancellous bone microarchitecture and formation. Sixty male Sprague-Dawley rats (6 months old) were randomly assigned to either cage control (CC), hind limb unloading (HU), HU plus either ALEN (HU + ALEN), SRT (HU + SRT), or a combination of ALEN and SRT (HU + SRT/ALEN) for 28 days. HU + SRT and HU + SRT/ALEN rats were anesthetized and subjected to muscle contractions once every 3 days during HU (four sets of five repetitions, 1000 ms isometric + 1000 ms eccentric). Additionally, HU + ALEN and HU + SRT/ALEN rats received 10 µg/kg of body weight of ALEN three times per week. HU reduced cancellous bone-formation rate (BFR) by 80%, with no effect of ALEN treatment (−85% versus CC). SRT during HU significantly increased cancellous BFR by 123% versus CC, whereas HU + SRT/ALEN inhibited the anabolic effect of SRT (−70% versus HU + SRT). SRT increased bone volume and trabecular thickness by 19% and 9%, respectively, compared with CC. Additionally, osteoid surface (OS/BS) was significantly greater in HU + SRT rats versus CC (+32%). Adding ALEN to SRT during HU reduced Oc.S/BS (−75%), Ob.S/BS (−72%), OS/BS (−61%), and serum TRACP5b (−36%) versus CC. SRT and ALEN each independently suppressed a nearly twofold increase in adipocyte number evidenced with HU and inhibited increases in osteocyte apoptosis. These results demonstrate the anabolic effect of a low volume of high-intensity muscle contractions during disuse and suggest that both bone resorption and bone formation are suppressed when SRT is combined with bisphosphonate treatment. © 2011 American Society for Bone and Mineral Research
Altered bone composition in children with vertebral fracture
Authors: Tamminen Inari S , Mäyränpää Mervi K , Turunen Mikael J , Isaksson Hanna , Mäkitie Outi , Jurvelin Jukka S , Kröger Heikki 
Published: April 2011

Abstract
Primary osteoporosis in children often leads to vertebral fractures, but it remains unknown whether these fractures associate with changes in bone composition. This study aimed to determine the differences in bone composition in fracture-prone children with and without vertebral fractures, as assessed by Fourier transform infrared spectroscopic imaging (FTIRI) and bone histomorphometry. Iliac crest bone biopsies (n = 24) were obtained from children who were suspected of primary osteoporosis based on evidence from the fracture history and/or low bone mineral density (BMD) by dual-energy X-ray absorptiometry. Vertebral morphology was determined by radiography. Bone biopsies were analyzed using histomorphometry and FTIRI. Phosphate-to-amide I, carbonate-to-phosphate, carbonate-to-amide I, and cross-link ratio (collagen maturity) were calculated. Children with (n = 14) and without (n = 10) vertebral fracture were compared. Low cancellous bone volume (BV/TV) was detected by histomorphometry in 36% of the children with vertebral fracture, and bone turnover rate was abnormal in 64% of them. Children with vertebral fractures had lower carbonate-to-phosphate ratios (p &lt; .05) and higher collagen maturity (p &lt; .05) than children without vertebral fracture. The children with low BV/TV in biopsy showed lower carbonate-to-amide I ratios (p &lt; .05) than the children with normal bone volume. This study showed changes in bone composition among fracture-prone children who had sustained a vertebral fracture. The observed changes in bone composition in these children may contribute to their greater propensity to sustain vertebral fractures. © 2011 American Society for Bone and Mineral Research
Current financial reporting issues
Authors: Ciesielski Jack T. , Weirich Thomas R. 
Published: April 2011

AbstractThe main theme of the latest Securities and Exchange Commission (SEC) and Public Company Accounting Oversights Board (PCAOB) Developments Conference was restoring public trust and investor confidence in the capital markets. Various speakers also noted the need for more transparency and improved disclosures by companies. Although there was not much discussion of strictly auditing issues, the conference provided a number of “heads‐up” warnings for both auditors and preparers. What signals are the SEC and PCAOB sending right now? What's on regulators' minds? The authors report in detail about all of it. © 2011 Wiley Periodicals, Inc.
Local staging of rectal cancer: A review of imaging
Authors: Beets‐Tan Regina G.H. , Beets Geerard L. 
Published: April 2011

AbstractDuring the past decades the management of patients with rectal cancer has substantially changed, with a significant reduction in local recurrence rates following the introduction of better imaging, better surgery, and more efficient neoadjuvant therapy. This review discusses the clinically relevant information radiologists should know on staging of rectal cancer patients. The crucial role of the radiologist in patient management is explained. Furthermore, the evidence for the use of magnetic resonance imaging (MRI) in staging and restaging of rectal cancer patients as well as the main features that need to be evaluated when interpreting rectal cancer MRI are given. New diagnostic challenges as a result of new treatment options are also discussed. J. Magn. Reson. Imaging 2011;33:1012–1019. © 2011 Wiley‐Liss, Inc.
Adaptive noise cancellation to suppress electrocardiography artifacts during real‐time interventional MRI
Authors: Wu Vincent , Barbash Israel M. , Ratnayaka Kanishka , Saikus Christina E. , Sonmez Merdim , Kocaturk Ozgur , Lederman Robert J. , Faranesh Anthony Z. 
Published: April 2011

AbstractPurpose:To develop a system for artifact suppression in electrocardiogram (ECG) recordings obtained during interventional real‐time magnetic resonance imaging (MRI).Materials and Methods:We characterized ECG artifacts due to radiofrequency pulses and gradient switching during MRI in terms of frequency content. A combination of analog filters and digital least mean squares adaptive filters were used to filter the ECG during in vivo experiments and the results were compared with those obtained with simple low‐pass filtering. The system performance was evaluated in terms of artifact suppression and ability to identify arrhythmias during real‐time MRI.Results:Analog filters were able to suppress artifacts from high‐frequency radiofrequency pulses and gradient switching. The remaining pulse artifacts caused by intermittent preparation sequences or spoiler gradients required adaptive filtering because their bandwidth overlapped with that of the ECG. Using analog and adaptive filtering, a mean improvement of 38 dB (n = 11, peak QRS signal to pulse artifact noise) was achieved. This filtering system was successful in removing pulse artifacts that obscured arrhythmias such as premature ventricular complexes and complete atrioventricular block.Conclusion:We have developed an online ECG monitoring system employing digital adaptive filters that enables the identification of cardiac arrhythmias during real‐time MRI‐guided interventions. J. Magn. Reson. Imaging 2011;33:1184–1193. © 2011 Wiley‐Liss, Inc.
Right ventricular outflow tract obstruction as a confounding factor in the assessment of the impact of pulmonary regurgitation on the right ventricular size and function in patients after repair of tetralogy of fallot
Authors: Śpiewak Mateusz , Biernacka Elżbieta K. , Małek Łukasz A. , Petryka Joanna , Kowalski Mirosław , Miłosz Barbara , Żabicka Magdalena , Miśko Jolanta , Rużyłło Witold 
Published: April 2011

AbstractPurpose:To compare right ventricular (RV) size and function between patients with combined pulmonary regurgitation (PR) plus RV outflow tract (RVOT) obstruction (RVOTO) and patients with isolated PR.Materials and Methods:Consecutive individuals with significant PR (PR fraction ≥20%) after tetralogy of Fallot (TOF) repair who underwent cardiovascular magnetic resonance (CMR) were included. Patients with additional hemodynamic abnormalities (residual ventricular septal defect, extracardiac shunt, and/or more than mild regurgitation at a valve other than the pulmonary valve) were excluded. Significant RVOTO was defined as peak gradient across RVOT ≥30 mmHg.Results:Significant differences between patients with combined PR+RVOTO (n = 9) and isolated PR (n = 33) were observed in RV end‐diastolic volume (138.6 ± 25.1 vs. 167.0 ± 34.6 mL/m2, P = 0.02, respectively), RV end‐systolic volume (65.0 ± 9.6 vs. 92.7 ± 26.2 mL/m2, P = 0.003), and RV ejection fraction (RVEF) (52.8 ± 3.7 vs. 45.0 ± 6.4%, P = 0.001). Both PR and peak RVOT gradient were independent predictors of RV size.Conclusion:Patients with combined PR+RVOTO had smaller RV volumes and higher RVEF when compared with patients with isolated PR. The confounding effect of RVOTO on RV size and function needs to be considered in CMR studies evaluating patients after TOF repair. J. Magn. Reson. Imaging 2011;33:1040–1046. © 2011 Wiley‐Liss, Inc.
New MR imaging methods for metallic implants in the knee: Artifact correction and clinical impact
Authors: Chen Christina A. , Chen Weitian , Goodman Stuart B. , Hargreaves Brian A. , Koch Kevin M. , Lu Wenmaio , Brau Anja C. , Draper Christine E. , Delp Scott L. , Gold Garry E. 
Published: April 2011

AbstractPurpose:To evaluate two magnetic resonance imaging (MRI) techniques, slice encoding for metal artifact correction (SEMAC) and multiacquisition variable‐resonance image combination (MAVRIC), for their ability to correct for artifacts in postoperative knees with metal.Materials and Methods:A total of 25 knees were imaged in this study. Fourteen total knee replacements (TKRs) in volunteers were scanned with SEMAC, MAVRIC, and 2D fast spin‐echo (FSE) to measure artifact extent and implant rotation. The ability of the sequences to measure implant rotation and dimensions was compared in a TKR knee model. Eleven patients with a variety of metallic hardware were imaged with SEMAC and FSE to compare artifact extent and subsequent patient management was recorded.Results:SEMAC and MAVRIC significantly reduced artifact extent compared to FSE (P < 0.0001) and were similar to each other (P = 0.58), allowing accurate measurement of implant dimensions and rotation. The TKRs were properly aligned in the volunteers. Clinical imaging with SEMAC in symptomatic knees significantly reduced artifact (P < 0.05) and showed findings that were on the majority confirmed by subsequent noninvasive or invasive patient studies.Conclusion:SEMAC and MAVRIC correct for metal artifact, noninvasively providing high‐resolution images with superb bone and soft tissue contrast. J. Magn. Reson. Imaging 2011;33:1121–1127. © 2011 Wiley‐Liss, Inc.
Longitudinal 3.0T MRI analysis of changes in lymph node volume and apparent diffusion coefficient in an experimental animal model of metastatic and hyperplastic lymph nodes
Authors: Klerkx Wenche M. , Geldof Albert A. , Heintz A. Peter , van Diest Paul J. , Visser Fredy , Mali Willem P. , Veldhuis Wouter B. 
Published: April 2011

AbstractPurpose:To perform a longitudinal analysis of changes in lymph node volume and apparent diffusion coefficient (ADC) in healthy, metastatic, and hyperplastic lymph nodes.Materials and Methods:Three groups of four female Copenhagen rats were studied. Metastasis was induced by injecting cells with a high metastatic potential in their left hind footpad. Reactive nodes were induced by injecting Complete Freund Adjuvant (CFA). Imaging was performed at baseline and at 2, 5, 8, 11, and 14 days after tumor cell injection. Finally, lymph nodes were examined histopathologically.Results:The model was highly efficient in inducing lymphadenopathy: subcutaneous cell or CFA inoculation resulted in ipsilateral metastatic or reactive popliteal lymph nodes in all rats. Metastatic nodal volumes increased exponentially from 5–7 mm3 at baseline to 25 mm3 at day 14, while the control node remained 5 mm3. The hyperplastic nodes showed a rapid volume increase reaching a plateau at day 6. The ADC of metastatic nodes significantly decreased (range 13%–32%), but this decrease was also seen in reactive nodes.Conclusion:Metastatic and hyperplastic lymph nodes differed in terms of enlargement patterns and ADC changes. Enlarged reactive or malignant nodes could not be differentiated based on their ADC values. J. Magn. Reson. Imaging 2011;33:1151–1159. © 2011 Wiley‐Liss, Inc.
Local specific absorption rate in high‐pass birdcage and transverse electromagnetic body coils for multiple human body models in clinical landmark positions at 3T
Authors: Yeo Desmond T.B. , Wang Zhangwei , Loew Wolfgang , Vogel Mika W. , Hancu Ileana 
Published: April 2011

AbstractPurpose:To use electromagnetic (EM) simulations to study the effects of body type, landmark position, and radiofrequency (RF) body coil type on peak local specific absorption rate (SAR) in 3T magnetic resonance imaging (MRI).Materials and Methods:Numerically computed peak local SAR for four human body models (HBMs) in three landmark positions (head, heart, pelvic) were compared for a high‐pass birdcage and a transverse electromagnetic 3T body coil. Local SAR values were normalized to the IEC whole‐body average SAR limit of 2.0 W/kg for normal scan mode.Results:Local SAR distributions were highly variable. Consistent with previous reports, the peak local SAR values generally occurred in the neck‐shoulder area, near rungs, or between tissues of greatly differing electrical properties. The HBM type significantly influenced the peak local SAR, with stockier HBMs, extending extremities towards rungs, displaying the highest SAR. There was also a trend for higher peak SAR in the head‐centric and heart‐centric positions. The impact of the coil types studied was not statistically significant.Conclusion:The large variability in peak local SAR indicates the need to include more than one HBM or landmark position when evaluating safety of body coils. It is recommended that an HBM with arms near the rungs be included to create physically realizable high‐SAR scenarios. J. Magn. Reson. Imaging 2011;33:1209–1217. © 2011 Wiley‐Liss, Inc.