bluuebunny/crossref_metadata_2025 huggingface dataset:
3D coronary motion tracking in swine models with MR tracking catheters
Authors: Schmidt Ehud J. , Yoneyama Ryuichi , Dumoulin Charles L. , Darrow Robert D. , Klein Eric , Kiruluta Andrew J.M. , Hayase Motoya
Published: December 2008

Purpose

To develop MR‐tracked catheters to delineate the three‐dimensional motion of coronary arteries at high spatial and temporal resolution.

Materials and Methods

Catheters with three tracking microcoils were placed into nine swine. During breath‐holds, electrocardiographic (ECG)‐synchronized 3D motion was measured at varying vessel depths. 3D motion was measured in American Heart Association left anterior descending (LAD) segments 6–7, left circumflex (LCX) segments 11–15, and right coronary artery (RCA) segments 2–3, at 60–115 beats/min heart rates. Similar‐length cardiac cycles were averaged. Intercoil cross‐correlation identified early systolic phase (ES) and determined segment motion delay.

Results

Translational and rotational motion, as a function of cardiac phase, is shown, with directionality and amplitude varying along the vessel length. Rotation (peak‐to‐peak solid‐angle RCA ≈0.10, LAD ≈0.06, LCX ≈0.18 radian) occurs primarily during fast translational motion and increases distally. LCX displacement increases with heart rate by 18%. Phantom simulations of motion effects on high‐resolution images, using RCA results, show artifacts due to translation and rotation.

Conclusion

Magnetic resonance imaging (MRI) tracking catheters quantify motion at 20 fps and 1 mm3 resolution at multiple vessel depths, exceeding that available with other techniques. Imaging artifacts due to rotation are demonstrated. Motion‐tracking catheters may provide physiological information during interventions and improve imaging spatial resolution. J. Magn. Reson. Imaging 2009;29:86–98. © 2008 Wiley‐Liss, Inc.
Three‐dimensional dynamic time‐resolved contrast‐enhanced MRA using parallel imaging and a variable rate k‐space sampling strategy in intracranial arteriovenous malformations
Authors: Petkova Mina , Gauvrit Jean‐Yves , Trystram Denis , Nataf François , Godon‐Hardy Sylvie , Munier Thierry , Oppenheim Catherine , Meder Jean‐François
Published: December 2008

Purpose

To evaluate the effectiveness of three‐dimensional (3D) dynamic time‐resolved contrast‐enhanced MRA (TR‐CE‐MRA) using a combination of a parallel imaging technique (ASSET: array spatial sensitivity encoding technique) and a time‐resolved method (TRICKS: time‐resolved imaging of contrast kinetics) and to compare it with 3D dynamic TR‐CE‐MRA using ASSET alone in the assessment of intracranial arteriovenous malformations (AVMs).

Materials and Methods

Twenty consecutive patients with angiographically confirmed AVMs were investigated using both 3D dynamic TR‐CE‐MRA techniques. Examinations were compared with respect to image quality, spatial resolution, number and type of feeders and drainers, nidus size, presence of early venous filling and temporal resolution. Digital subtraction angiography was used as standard of reference.

Results

The higher temporal and spatial resolution of 3D dynamic TR‐CE‐MRA TRICKS ASSET allowed a better assessment of intracranial vascular malformations, namely better depiction of feeders, drainers and better detection of early venous drainage. There was no significant difference between them in terms of nidus size.

Conclusion

3D dynamic TR‐CE‐MRA combining parallel imaging and a time‐resolved method with subsecond and submillimeter resolution could become the first‐line investigation technique in both diagnosis and follow‐up of intracranial AVMs. J. Magn. Reson. Imaging 2009;29:7–12. © 2008 Wiley‐Liss, Inc.
Restricted canonical correlation analysis in functional MRI—validation and a novel thresholding technique
Authors: Ragnehed Mattias , Engström Maria , Knutsson Hans , Söderfeldt Birgita , Lundberg Peter
Published: December 2008

Purpose

To validate the performance of an analysis method for fMRI data based on restricted canonical correlation analysis (rCCA) and adaptive filtering, and to increase the usability of the method by introducing a new technique for significance estimation of rCCA maps.

Materials and Methods

Activation data from a language task and also a resting state fMRI data were collected from eight volunteers. Data was analyzed using both the rCCA method and the General Linear Model (GLM). A modified Receiver Operating Characteristic (ROC) method was used to evaluate the performance of the different analysis methods. The area under a fraction of the ROC curve was used as a measure of performance. On resting state data the fraction of voxels above certain significance thresholds were used to evaluate the significance estimation method.

Results

The rCCA method scored significantly higher on the area under the ROC curve than the GLM. The fraction of activated voxels determined by thresholding according to the introduced significance estimation technique showed good agreement with the thresholds selected.

Conclusion

The rCCA method is an effective analysis tool for fMRI data and its usability is increased with the introduced significance estimation method. J. Magn. Reson. Imaging 2009;29:146–154. © 2008 Wiley‐Liss, Inc.
Retrospective 3D registration of trabecular bone MR images for longitudinal studies
Authors: Magland Jeremy F. , Jones Catherine E. , Leonard Mary B. , Wehrli Felix W.
Published: December 2008

Purpose

To evaluate an automatic 3D registration algorithm for serial high‐resolution images of trabecular bone (TB) in studies designed to evaluate the response of the trabecular architecture to intervention or disease progression.

Materials and Methods

An efficient algorithm for registering high‐resolution 3D images of TB is presented. The procedure identifies the six parameters of rigid displacement between two scans performed at different timepoints. By assuming a relatively small through‐plane rotation, considerable time is saved by combining the results of a collection of regional 2D registrations throughout the TB region of interest (ROI). The algorithm was applied to 26 pairs of MR images acquired 6 months apart. Reproducibility of local TB structural parameters (plate, rod, and junction density) computed in manually selected regions were compared between baseline and registered follow‐up images.

Results

All 26 registrations were completed successfully in less than 30 seconds per image pair. The resampled follow‐up images agreed with baseline to around one pixel throughout the volume at 137 × 137 × 410 μm3 image resolution. Structural parameters in each region correlated well from baseline to follow‐up with intraclass correlation coefficients ranging between 85%–97% for TB plate density. Interregional variations in the parameters were large as compared with intraregion reproducibility.

Conclusion

The proposed algorithm was successful in automatically registering baseline and follow‐up TB images in a translational study, and may be useful in regional analyses in longitudinal MR studies of TB architecture. J. Magn. Reson. Imaging 2009;29:118–126. © 2008 Wiley‐Liss, Inc.
Optimum fuzzy filters for phase‐contrast magnetic resonance imaging segmentation
Authors: Sundareswaran Kartik S. , Frakes David H. , Fogel Mark A. , Soerensen Dennis D. , Oshinski John N. , Yoganathan Ajit P.
Published: December 2008

Purpose

To develop and validate a multidimensional segmentation and filtering methodology for accurate blood flow velocity field reconstruction from phase‐contrast magnetic resonance imaging (PC MRI).

Materials and Methods

The proposed technique consists of two steps: (1) the boundary of the vessel is automatically segmented using the active contour approach; and (2) the noise embedded within the segmented vector field is selectively removed using a novel fuzzy adaptive vector median filtering (FAVMF) technique. This two‐step segmentation process was tested and validated on 111 synthetically generated PC MRI slices and on 10 patients with congenital heart disease.

Results

The active contour technique was effective for segmenting blood vessels having a sensitivity and specificity of 93.1% and 92.1% using manual segmentation as a reference standard. FAVMF was the superior technique in filtering out noise vectors, when compared with other commonly used filters in PC MRI (P < 0.05). The peak wall shear rate calculated from the PC MRI data (248 ± 39 sec−1), was significantly decreased to (146 ± 26 sec−1) after the filtering process.

Conclusion

The proposed two‐step segmentation and filtering methodology is more accurate compared to a single‐step segmentation process for post‐processing of PC MRI data. J. Magn. Reson. Imaging 2009;29:155–165. © 2008 Wiley‐Liss, Inc.
Cerebral blood flow estimation in vivo using local tissue reference functions
Authors: Kosior Jayme Cameron , Smith Michael R. , Kosior Robert Karl , Frayne Richard
Published: December 2008

Purpose

To evaluate the use of bolus signals obtained from tissue as reference functions (or local reference functions [LRFs]) rather than arterial input functions (AIFs) when deriving cross‐calibrated cerebral blood flow (CBFCC) estimates via deconvolution.

Materials and Methods

AIF and white matter (WM) LRF CBFCC maps (cross‐calibrated so that normal WM was 23.7 mL/minute/100 g) derived using singular value decomposition (SVD) were examined in 28 ischemic stroke patients. Median CBFCC estimates from normal gray matter (GM) and ischemic tissue were obtained.

Results

AIF and LRF median CBFCC estimates resembled one another for all 28 patients (average paired CBFCC difference 0.4 ± 1.7 mL/minute/100 g and –0.4 ± 1.4 mL/minute/100 g in GM and ischemic tissue, respectively). Wilcoxon signed‐rank comparisons of patient median CBFCC measurements revealed no statistically significant differences between using AIFs and LRFs (P > 0.05).

Conclusion

If CBF is quantified using a patient‐specific cross‐calibration factor, then LRF CBF estimates are at least as accurate as those from AIFs. Therefore, until AIF quantification is achievable in vivo, perfusion protocols tailored for LRFs would simplify the methodology and provide more reliable perfusion information. J. Magn. Reson. Imaging 2009;29:183–188. © 2008 Wiley‐Liss, Inc.
Combination of Mn2+‐enhanced and diffusion tensor MR imaging gives complementary information about injury and regeneration in the adult rat optic nerve
Authors: Thuen Marte , Olsen Øystein , Berry Martin , Pedersen Tina Bugge , Kristoffersen Anders , Haraldseth Olav , Sandvig Axel , Brekken Christian
Published: December 2008

Purpose

To evaluate manganese (Mn2+)‐enhanced MRI (MEMRI) and diffusion tensor imaging (DTI) as tools for detection of axonal injury and regeneration after intravitreal peripheral nerve graft (PNG) implantation in the rat optic nerve (ON).

Materials and Methods

In adult Fischer rats, retinal ganglion cell (RGC) survival was evaluated in Flurogold (FG) back‐filled retinal whole mounts after ON crush (ONC), intravitreal PNG, and intravitreal MnCl2 injection (150 nmol) at 0 and 20 days post lesion (dpl). MEMRI and echo‐planar DTI (DTI‐EPI) was obtained of noninjured ON one day after intravitreal MnCl2 injection, and at 1 and 21 dpl after ONC, intravitreal PNG, and intravitreal MnCl2 injections given at 0 and 20 dpl. GAP‐43 immunohistochemistry was performed after the last MRI.

Results

ONC reduced RGC density in retina by 94% at 21 dpl compared to noninjured ON without MnCl2 injections. Both intravitreal PNG and intravitreal MnCl2 injections improved RGC survival in retina, which was reduced by 90% (ONC+MnCl2), 82% (ONC+PNG), and 74% (ONC+PNG+MnCl2) compared to noninjured ON. DTI‐derived parameters (fractional anisotropy [FA], mean diffusivity, axial diffusivity λ∥, and radial diffusivity λ⟂) were unaffected by the presence of Mn2+ in the ON. At 1 dpl, CNRMEMRI and λ∥ were reduced at the injury site, while at 21 dpl they were increased at the injury site compared to values measured at 1 dpl. GAP‐43 immunoreactive axons were present in the ON distal to the ONC injury site.

Conclusion

MEMRI and DTI enabled detection of functional and structural degradation after rat ON injury, and there was correlation between the MRI‐derived and immunohistochemical measures of axon regeneration. J. Magn. Reson. Imaging 2009;29:39–51. © 2008 Wiley‐Liss, Inc.
Novel technique used to detect swallowing in volume‐selective turbo spin‐echo (TSE) for carotid artery wall imaging
Authors: Chan Cheuk F. , Gatehouse Peter D. , Hughes Ray , Roughton Michael , Pennell Dudley J. , Firmin David N.
Published: December 2008

Purpose

To improve three‐dimensional (3D) volume‐selective turbo spin‐echo (TSE) carotid wall imaging by the addition of a novel body surface swallowing detection device.

Material and Methods

A 3D volume‐selective TSE sequence was used to image the carotid artery. A novel carbon‐fiber motion device, positioned over the laryngeal prominence, was used to detect swallowing movement. An electrical output generated by coil movement was used to detect motion, and an algorithm was programmed to reject data acquired during swallowing and for a short period afterwards. Images were acquired with and without the algorithm and scored on a scale of 0–5 by four independent blinded observers according to the clarity of the vessel wall, e.g., 0 = poor image quality and 5 = excellent quality images with little or no artifact.

Results

The scans with the rejection algorithm on were scored higher than the scans without the algorithm. The comparison of scores with the algorithm on vs. the algorithm off were as follows: mean ± standard deviation (SD) = 3.76 ± 0.25, 95% confidence interval (CI) = 3.27–4.25 vs. 2.64 ± 0.25, 95% CI = 2.15–3.13; with good interobserver correlation (Kendall's W score 0.77).

Conclusion

Image quality can be improved by the algorithm during acquisition. This can be achieved by a novel, anatomically positioned superficial device. This may help in prolonged 3D scans where a single movement can corrupt the entire acquisition. J. Magn. Reson. Imaging 2009;29:211–216. © 2008 Wiley‐Liss, Inc.
Safety of ferucarbotran in MR imaging of the liver: A pre‐ and postexamination questionnaire‐based multicenter investigation
Authors: Onishi Hiromitsu , Murakami Takamichi , Kim Tonsok , Hori Masatoshi , Hirohashi Shinji , Matsuki Mitsuru , Narumi Yoshifumi , Imai Yasuharu , Sakurai Kousuke , Nakamura Hironobu
Published: December 2008

Purpose

To prospectively investigate, by means of a pre‐and postexamination questionnaire, the types and frequency of adverse reactions to ferucarbotran (Resovist), a superparamagnetic iron oxide (SPIO) contrast agent.

Materials and Methods

This study was approved by the ethics committee of each of the institutions involved, and all patients gave written informed consent. One questionnaire asking about baseline symptoms before the injection of ferucarbotran, and one about adverse events over a period of seven days after injection were given to 315 patients who underwent ferucarbotran‐enhanced magnetic resonance imaging (MRI) of the liver at several institutions. The data for baseline symptoms were used for reference to exclude false‐positive adverse reactions and were also compared with the adverse event data to determine with McNemar's chi‐squared test the incidence of each symptom.

Results

Before MR examination, 249 clinical symptoms were reported by 102 of 315 patients (32.4%). After the injection of ferucarbotran, 169 adverse events were observed in 78 patients (24.8%). Eventually, 70 adverse events occurring in 45 patients (14.3%) were judged to be adverse reactions to ferucarbotran, defined as possibly or definitely ferucarbotran‐related events. All reactions were of mild intensity.

Conclusion

Ferucarbotran can be considered safe for clinical use in liver MRI. J. Magn. Reson. Imaging 2009;29:106–111. © 2008 Wiley‐Liss, Inc.
Contrast agent dose effects in cerebral dynamic susceptibility contrast magnetic resonance perfusion imaging
Authors: Alger Jeffry R. , Schaewe Timothy J. , Lai Tom C. , Frew Andrew J. , Vespa Paul M. , Etchepare Maria , Liebeskind David S. , Saver Jeffrey L. , Kidwell S. Chelsea
Published: December 2008

Purpose

To study the contrast agent dose sensitivity of hemodynamic parameters derived from brain dynamic susceptibility contrast MRI (DSC‐MRI).

Materials and Methods

Sequential DSC‐MRI (1.5T gradient‐echo echo‐planar imaging using an echo time of 61–64 msec) was performed using contrast agent doses of 0.1 and 0.2 mmol/kg delivered at a fixed rate of 5.0 mL/second in 12 normal subjects and 12 stroke patients.

Results

1) Arterial signal showed the expected doubling in relaxation response (ΔR2*) to dose doubling. 2) The brain signal showed a less than doubled ΔR2* response to dose doubling. 3) The 0.2 mmol/kg dose studies subtly underestimated cerebral blood volume (CBV) and cerebral blood flow (CBF) relative to the 0.1 mmol/kg studies. 4) In the range of low CBV and CBF, the 0.2 mmol/kg studies overestimated the CBV and CBF compared with the 0.1 mmol/kg studies. 5) The 0.1 mmol/kg studies reported larger ischemic volumes in stroke.

Conclusion

Subtle but statistically significant dose sensitivities were found. Therefore, it is advisable to carefully control the contrast agent dose when DSC‐MRI is used in clinical trials. The study also suggests that a 0.1 mmol/kg dose is adequate for hemodynamic measurements. J. Magn. Reson. Imaging 2009;29:52–64. © 2008 Wiley‐Liss, Inc.
Phosphorus‐31 magnetic resonance spectroscopy of skeletal muscle in maternally inherited diabetes and deafness A3243G mitochondrial mutation carriers
Authors: van Elderen Saskia G.C. , Doornbos Joost , van Essen Einar H.R. , Lemkes Herman H.P.J. , Maassen J. Antonie , Smit Jan W.A. , de Roos Albert
Published: December 2008

Purpose

To investigate high‐energy phosphate metabolism in striated skeletal muscle of patients with Maternally Inherited Diabetes and Deafness (MIDD) syndrome.

Materials and Methods

In 11 patients with the MIDD mutation (six with diabetes mellitus [DM] and five non‐DM) and eight healthy subjects, phosphocreatine (PCr) and inorganic phosphate (Pi) in the vastus medialis muscle was measured immediately after exercise using 31P‐magnetic resonance spectroscopy (MRS). The half‐time of recovery (t1/2) of monoexponentially fitted (PCr+Pi)/PCr was calculated from spectra obtained every 4 seconds after cessation of exercise. A multiple linear regression model was used for statistical analysis.

Results

Patients with the MIDD mutation showed a significantly prolonged t1/2 (PCr+Pi)/PCr after exercise as compared to controls (13.6±3.0 vs. 8.7±1.3 sec, P = 0.01). No association between the presence of DM and t1/2 (PCr + Pi)/PCr was found (P = 0.382).

Conclusion

MIDD patients showed impaired mitochondrial oxidative phosphorylation in skeletal muscle shortly after exercise, irrespective of the presence of DM. J. Magn. Reson. Imaging 2009;29:127–131. © 2008 Wiley‐Liss, Inc.
Higher‐order contrast functions improve performance of independent component analysis of fMRI data
Authors: Schmithorst Vincent J.
Published: December 2008

Purpose

To evaluate the performance of different contrast functions used in Independent Component Analysis (ICA) of functional magnetic resonance imaging (fMRI) data at low signal‐to‐noise ratio (SNR), present in fMRI paradigms such as resting‐state acquisitions.

Materials and Methods

Metrics were defined to estimate both the accuracy and robustness of contrast functions under varying source distributions. Simulations were performed to compare the performance of lower‐order (such as ln cosh) to higher‐order (such as kurtosis) contrast functions using Laplacian source distributions corrupted with Gaussian noise. The ln cosh and kurtosis contrast functions were also compared using resting‐state fMRI data from 10 normal adult volunteers.

Results

Higher‐order contrast functions provided superior performance compared to lower‐order contrast functions in the evaluation of metrics and via the simulations in the presence of a significant amount of noise. The performance of kurtosis was not statistically significantly different from that of a theoretically optimized contrast function. The choice of contrast function was found to result in substantial (R < 0.9) differences in 40% of the components found from the resting‐state fMRI data.

Conclusion

The use of higher‐order contrast functions, such as kurtosis, may provide superior performance in ICA analysis of fMRI data with low SNR. J. Magn. Reson. Imaging 2009;29:242–249. © 2008 Wiley‐Liss, Inc.
Improved bolus arrival time and arterial input function estimation for tracer kinetic analysis in DCE‐MRI
Authors: Singh Anup , Rathore Ram K. Singh , Haris Mohammad , Verma Sanjay K. , Husain Nuzhat , Gupta Rakesh K.
Published: December 2008

Purpose

To develop a methodology for improved estimation of bolus arrival time (BAT) and arterial input function (AIF) which are prerequisites for tracer kinetic analysis of dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) data and to verify the applicability of the same in the case of intracranial lesions (brain tumor and tuberculoma).

Materials and Methods

A continuous piecewise linear (PL) model (with BAT as one of the free parameters) is proposed for concentration time curve C(t) in T1‐weighted DCE‐MRI. The resulting improved procedure suggested for automatic extraction of AIF is compared with earlier methods. The accuracy of BAT and other estimated parameters is tested over simulated as well as experimental data.

Results

The proposed PL model provides a good approximation of C(t) trends of interest and fit parameters show their significance in a better understanding and classification of different tissues. BAT was correctly estimated. The automatic and robust estimation of AIF obtained using the proposed methodology also corrects for partial volume effects. The accuracy of tracer kinetic analysis is improved and the proposed methodology also reduces the time complexity of the computations.

Conclusion

The PL model parameters along with AIF measured by the proposed procedure can be used for an improved tracer kinetic analysis of DCE‐MRI data. J. Magn. Reson. Imaging 2009;29:166–176. © 2008 Wiley‐Liss, Inc.
Soil organic carbon and nitrogen fractions and water‐stable aggregation as affected by cropping and grassland reclamation in an arid sub‐alpine soil
Authors: Li Xiao Gang , Zhang Ping Liang , Yin Ping , Li Yin Ke , Ma Qi Fu , Long Rui Jun , Li Feng Min
Published: December 2008

This paper investigates effects of cropping abandonment and perennial grass growing on soil organic C and N pools and aggregate stability, by comparing soils under native grassland, crop cultivation, perennial grass growing and cropping abandonment, in degraded cropland at a sub‐alpine site in north‐western China. The pools of total and particulate organic C (115 and 37 Mg ha−1) in the 0–30 cm soil layer of native grassland were reduced by 31 and 54% after 30 years of crop cultivation. After 4 years of conversion from cropland to perennial grass growing total and particulate organic C pools were increased by 29 and 56%, whereas 4 year cropping abandonment increased particulate organic C by 36%. Rapid increases in total and particulate N were also found in perennial grass growing and cropping abandonment soils. The native grassland soil and soils of cropping abandonment and perennial grass growing had higher carbohydrate C concentrations in the 0–10 cm layer than the cropped soil. The rapid recovery of particulate organic fraction and carbohydrates in the re‐vegetated soils were probably due to higher plant biomass inputs and lower organic matter decomposition compared with those in the cropped soil. Aggregate stability of the 0–30 cm soil layer was significantly decreased by crop cultivation but showed a good recovery after 4 year re‐vegetations. This study suggests that reduction of soil organic matter and aggregate stability under crop cultivation may be remedied by cropping abandonment or perennial grass growing. Copyright © 2008 John Wiley & Sons, Ltd.
Life history of a mule (c. 160 AD) from the Roman fort Biriciana/Weißenburg (Upper Bavaria) as revealed by serial stable isotope analysis of dental tissues
Authors: Berger T. E. , Peters J. , Grupe G.
Published: December 2008

The presence of the osseous remains of at least four mules in a garbage dump at the Roman fort of Biriciana near the town of Weißenburg, Upper Bavaria, dating to c. 160 AD, raised the question as to whether mule breeding was already performed to the north of the Alps during the Middle Roman Empire, or whether these animals still had to be imported from the Mediterranean. Serial analyses of the dental enamel and dentine of a lower fourth premolar and the surrounding alveolar bone of a mandible of a mule in terms of stable strontium isotopic ratios of the apatite, and stable carbon and oxygen isotope ratios of the structural carbonate, were carried out to test whether this individual moved long distances during its lifetime. Since isotopic ratios obtained by serial analysis can be correlated with consecutive ontogenetic stages, it can be assumed that this particular individual experienced significant changes in terms of diet and environmental parameters after its eighth year of life. These changes included a period of residence in a region of high altitude, most likely the Alps considering the location of the Roman fort where the mule was found. The isotopic data obtained do not contradict the assumption that this animal was bred and raised in northern Italy, to frequent later in its adult life the Alps and finally perish at Biriciana/Weißenburg. Copyright © 2008 John Wiley & Sons, Ltd.
Validation of death and suicide recording on the THIN UK primary care database
Authors: Hall Gillian C.
Published: December 2008

Purpose

Data from a cohort study were used to investigate death and cause of death (COD) recording on the THIN UK primary care database.

Methods

Subjects from 118 practices had a body mass index recorded, 2002–2003 (index date), no recent pregnancy or emotional event, or cancer. Coded and free text entries were searched for a COD for deaths dated ≤485 days after index date. External documents were requested when date or COD were unclear, suicide was possible, and for a random sample of 40 patients with a COD identified.

Results

Five of 1399 deaths dated within 1 year of the index date had not died (positive predictive value 99.6%) and 4 of 222 dated within 366–485 days had died during the year (sensitivity 99.7%). A database COD was identified for 887 (63.4%) with external documents received for 597 (92.8% requested). Of 40 compared with external sources, the underlying COD was on the database in 33 (82.5%), and could be identified as such in 26 (65%). The date was within 1 day of that on external documents in 504 (94.9%) with a date of death but 3 (5.7%) with only a transfer‐out of practice date. One of seven suicides was recorded as such.

Conclusion

Any database record of death or its date is reliable, but transfer‐out date is often later. Studies of COD or acute, potentially fatal conditions will miss cases unless a COD is obtained for all fatalities. Most suicides are not noted as such on the electronic record. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of various measures for assessing medication refill adherence using prescription data
Authors: Vink N. M. , Klungel O. H. , Stolk R. P. , Denig P.
Published: December 2008

Background

Several measures using prescription data have been developed for estimating medication refill adherence. Few studies have made direct comparisons, and little is known about the accuracy of these measures in patients on a multiple‐drug regimen.

Purpose

To compare different calculation methods using prescription data for assessing refill adherence.

Method

An observational cohort study among type 2 diabetes patients was conducted. Adherence to oral glucose‐lowering, antihypertensive and lipid‐lowering medication was assessed for 2004. We calculated medication possession ratios in a flexible period (MPRF), per calendar year (MPRY) and gaps between refills (GAP) at drug class and therapeutic level. Individual review of drug prescription profiles was conducted to validate identified cases of suboptimal refill adherence. Differences in Area Under the Curve (AUC) of ROC‐curves were calculated to compare the methods.

Results

Of the 3877 patients, 2969 (77%) patients received oral glucose‐lowering medication, 2715 (70%) antihypertensives and 1797 (46%) lipid‐lowering medication. Using cutoffs for MPR < 80% and GAP > 30 days, overall rates of suboptimal adherence for these drug classes were 32, 35 and 23% respectively. AUC for measures calculated at drug class level (range 0.85–0.90) were significantly larger than those calculated at therapeutic level (0.72–0.90). For oral glucose‐regulating medication and antihypertensives, AUCs were largest for the MPRY and GAP measures (0.87–0.88). For lipid‐lowering medication, the AUC was largest for the GAP measure (0.90).

Conclusions

Differences between adherence measures were small and favoured calculation on drug class level. For multiple drug use, both MPRY and GAP were good measures for identifying suboptimal refill adherence. Copyright © 2008 John Wiley & Sons, Ltd.
Origin of the low carrier lifetime edge zone in multicrystalline PV silicon
Authors: Nærland Tine Uberg , Arnberg Lars , Holt Arve
Published: December 2008

An investigation of impurities, crystal defects and microstructure has been performed on the edge zone, i.e. close to the crucible wall, which experiences reduced carrier lifetime in a directionally solidified multicrystalline p‐doped silicon ingot. The characterization methods applied have been QSSPC, FTIR, μW‐PCD, EBSD, CDI, PVScan, optical microscopy, FeB‐pair splitting and GDMS. The results of the minority carrier lifetime measurements have revealed strongly reduced values in the vicinity of the edge (< 1 μs). Increased values were obtained starting at 15–17 mm from the edge. Light elements analyses showed that the O, N and C concentrations, interstitially or in particles, did not increase in the edge zone, neither did the dislocation density. GDMS analyses detected traces of aluminium, iron, copper, titanium and chromium. The total iron concentration showed an increase towards the edge, though high concentrations were occasionally detected in the bulk. FeB pair analysis revealed large concentrations of Fe (∼1 × 1013 cm−3) in the vicinity of the edge with a distinctively decreasing trend moving away from the edge. The detected FeB‐concentrations are sufficient to account for the majority of the lifetime degradation close to the edge (0‐‐15 mm). In addition, Fe, in the form of FeB pairs, was extensively observed as object to internal gettering to high angle boundaries and dislocations. Fe, in the form of FeB pairs, is furthermore believed to originate from solid state diffusion from the crucible and coating. Copyright © 2008 John Wiley & Sons, Ltd.
Aromatic nitro substitution reaction between 4‐nitro‐N‐n‐butyl‐1,8‐naphthalimide and n‐heptanethiol in water–methanol binary mixtures
Authors: Triboni Eduardo Rezende , Artur Julio Cesar , Filho Pedro Berci , Cuccovia Iolanda Midea , Politi Mario José
Published: December 2008

The second‐order rate constants of thiolysis by n‐heptanethiol on 4‐nitro‐N‐n‐butyl‐1,8‐naphthalimide (4NBN) are strongly affected by the water–methanol binary mixture composition reaching its maximum at around 50% mole fraction. In parallel solvent effects on 4NBN absorption molar extinction coefficient also shows a maximum at this composition region. From the spectroscopic study of reactant and product and the known H‐bond capacity of the mixture a rationalization that involves specific solvent H‐donor interaction with the nitro group is proposed to explain the kinetic data. Present findings also show a convenient methodology to obtain strongly fluorescent imides, valuable for peptide and analogs labeling as well as for thio‐naphthalimide derivatives preparations. Copyright © 2008 John Wiley & Sons, Ltd.
A new visible light sensitive photoinitiator system for the cationic polymerization of epoxides
Authors: Crivello James V.
Published: December 2008

This communication reports the development of an efficient three‐component visible light sensitive photoinitiator system for the cationic ring‐opening photopolymerization of epoxide monomers and epoxide functional oligomers. The photoinitiator system consists of camphorquinone in combination with a benzyl alcohol to generate free radicals by the absorption of visible light. Subsequently, the radicals participate in the free radical chain induced decomposition of a diaryliodonium salt. The resulting strong Brønsted acid derived from this process catalyzes the cationic ring‐opening polymerization of a variety of epoxide substrates. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 866–875, 2009
Positron annihilation lifetime and differential scanning calorimetric study of immiscible NBR/PE blends
Authors: Gomaa E. , Aly E. Hassan , Mohsen M.
Published: December 2008

The temperature dependence of the mean size of nanoscale free‐volume holes, 〈Vh〉, in polymer blend system consisting of polar and nonpolar polymers has been investigated. The positron lifetime spectra were measured for a series of polymer blends between polyethylene (PE) and nitrile butadiene rubber (NBR) as a function of temperature from 100 to 300 K. The glass transition temperatures (Tg) for blends were determined from the ortho‐positronium (o‐Ps) lifetime τ3 and the mean size of free‐volume holes 〈Vh〉 versus temperature as a function of wt % of NBR. The Tgs estimated from the PALS data agree very well with those estimated from DSC in view of different time scales involved in the two measurements. Both DSC and PALS results for the blends showed two clear Tgs of a two‐phase system. Furthermore, from the variation of thermal expansivity of the nanoscale free‐volume holes, the thermal expansion coefficients of glass and amorphous phases were estimated. Variations of the o‐Ps formation probability I3 versus temperature for pure PE and blends with low wt % of NBR were interpreted on the basis of the spur reaction model of Ps formation with reference to the effects of localized electrons and trapping centers produced by positron irradiation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 227–238, 2009
Phase behavior and properties of polyvinyl alcohol/gelatin blends with novel pH‐dependence
Authors: Su Run , Su Juanxia , Wang Ke , Chen Daiqiang , Yang Changyue , Fu Qiang
Published: December 2008

A novel change of phase behavior and properties of polyvinyl alcohol (PVA)/gelatin blends as a function of pH was reported. The PVA/gelatin blends were found to be completely miscible in acidic condition (pH < 4), partially miscible in basic condition (pH > 8), and immiscible in neutral condition (pH was ca. 6). As a result, the membranes cast from acidic condition showed the highest tensile strength and the lowest alcohol vapor permeation (AVP) rate; those obtained from neutral condition showed the lowest tensile strength and highest AVP rate; the properties of membranes cast from basic condition lay in between. The interaction between PVA and gelatin was investigated via Fourier transform infrared spectrum (FTIR), differential scanning calorimetry (DSC), and Zetasizer measurement. The novel pH‐dependence of the blends was ascribed to the protonation of amino groups of gelatin in acidic condition, which resulted in a strong electrostatic attraction between NH of gelatin and OH of PVA. The partial miscibility in basic condition was due to the ionization of carboxyl groups of gelatin, which caused a stretching of gelatin via electrostatic repulsive force and a breakage of the H‐bonding among the molecular chains, leading to a limited interaction between PVA and gelatin and forming a partially miscible blend. In neutral conditions, there were almost no charges (very limited protonation and ionization) at the weak polyampholyte gelatin, and the strong H‐bonding among gelatin molecules themselves or PVA molecules themselves caused the phase separation between gelatin and PVA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 239–247, 2009
Morphology and crystallization behavior of poly(vinylidene fluoride)/poly(methyl methacrylate)/methyl salicylate, and benzophenone systems via thermally induced phase separation
Authors: Ma Wenzhong , Chen Shuangjun , Zhang Jun , Wang Xiaolin , Miao Wenhu
Published: December 2008

Poly(vinylidene fluoride) (PVDF) blend microporous membranes were prepared by PVDF/poly(methyl methacrylate) blend (with mass ratio = 70/30) via thermally induced phase separation. Benzophenone (BP) and methyl salicylate (MS) were used as diluents. The phase diagram calculations were carried out in terms of a pseudobinary system, considering the PVDF blend to be one component. The crytallization behaviors of PVDF in the dilutions were detected by differential scanning calorimetry measurement. In these two systems, the melting and crystallization temperatures leveled off in the low polymer concentration (<40 wt %), but shifted to a higher temperature when the polymer concentration >40 wt %. The calculated crystallinity of PVDF for samples with low polymer concentrations was greater than those with high polymer concentrations, because of the limited mobility of polymer chains at a high polymer concentration. The membrane structure as determined by scanning electron microscopy depended on the phase separation mechanism. The quenched samples mainly illustrated the occurrence of crystallization on the same time scale as the liquid–liquid phase separated, resulting in the obvious spherulitic structure with small pores in the spherulites. As the polymer concentration increased, the size of the spherulites and pores within the spherulite was decreased. The evaluated porosity for BP diluted system was higher than that for MS diluted system, and decreased with the increased polymer concentration. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 248–260, 2009
Crystallization improvement of poly(L‐lactide) induced by functionalized multiwalled carbon nanotubes
Authors: Li Yanli , Wang Yong , Liu Li , Han Liang , Xiang Fangming , Zhou Zuowan
Published: December 2008

In the present work, the crystalline structures and the melting behaviors of poly(L‐lactide) (PLLA) obtained after being annealed at different conditions have been investigated through differential scanning calorimetry and wide‐angle X‐ray diffraction, respectively. To improve the crystallization of PLLA, functionalized multiwalled carbon nanotubes (f‐MWCNTs) are introduced into PLLA. Our results show that by prolonging the annealing duration or enhancing the annealing temperature, the degree of crystallinity of PLLA gradually increases. Very important, the addition of f‐MWCNTs promotes the cold‐crystallization of PLLA dramatically even at relatively lower annealing temperature or in shorter annealing duration. Further results show that, whether in neat PLLA or in PLLA/f‐MWCNTs nanocomposite, only α form crystal forms during the annealing process. The glass transition temperature shifts to high temperatures because of the increase of crystallinity. F‐MWCNTs exhibit great heterogeneous nucleation effect for PLLA crystallization through enhancing the nucleation density, leading to homogeneous and tiny spherulites formation in a very short time. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 326–339, 2009
Modern valence bond description of the electronic mechanism of a [1,3] sigmatropic rearrangement linking bicyclo[3.2.0]hept‐2‐ene and bicyclo[2.2.1]hept‐2‐ene (norbornene)
Authors: Karadakov Peter B. , Cooper David L. , Uhe Andreas
Published: December 2008

Modern valence bond theory, in its spin‐coupled (SC) form, is used to examine the bond‐breaking and bond‐making processes that take place along the lowest‐energy path for a gas‐phase [1,3] sigmatropic rearrangement linking bicyclo[3.2.0]hept‐2‐ene and bicyclo[2.2.1]hept‐2‐ene (norbornene). The changes within the SC wave functions depicting the direct “suprafacial with inversion” pathway reveal in a very clear cut way the singlet diradical character of structures along the plateau in the energy profile. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Relationship between first polar body morphology before intracytoplasmic sperm injection and fertilization rate, cleavage rate, and embryo quality
Authors: Navarro Paula Andrea , de Araújo Maria Medeiros , de Araújo Carlos Medeiros , Rocha Marcelo , dos Reis Rosana , Martins Wellington
Published: December 2008

Objectives

To evaluate the influence of the morphology of the first polar body (PB) on intracytoplasmic sperm injection (ICSI) outcomes.

Methods

The morphology of the first PB was assessed in 3177 metaphase II oocytes and classified as: intact and normal size, fragmented, or enlarged size. The rates of fertilization, cleavage, and embryo quality were evaluated on day 2.

Results

The rates of fertilization, cleavage, and formation of good quality embryos resulting from the insemination of oocytes with an enlarged first PB (20.7%, 18.7%, and 5.0%, respectively) were significantly lower than those for oocytes with an intact first PB of normal size (70.8%, 62.5%, and 19%, respectively) or a fragmented first PB (69.7%, 60.5%, and 17.1%, respectively). Rates did not differ significantly between oocytes with an intact first PB of normal size and oocytes with a fragmented first PB (P > 0.05).

Conclusions

The presence of an enlarged PB is related to poorer rates of fertilization, cleavage, and top quality embryos. However, identification of first PB fragmentation does not seem to interfere with ICSI outcomes.
Effect of β-carotene-rich tomato lycopene β-cyclase (tlcy-b) on cell growth inhibition in HT-29 colon adenocarcinoma cells
Authors: Palozza Paola , Bellovino Diana , Simone Rossella , Boninsegna Alma , Cellini Francesco , Monastra Giovanni , Gaetani Sancia
Published: December 2008

Lycopene β-cyclase (tlcy-b) tomatoes, obtained by modulating carotenogenesis via genetic engineering, contain a large amount of β-carotene, as clearly visible by their intense orange colour. In the present study we have subjectedtlcy-btomatoes to anin vitrosimulated digestion and analysed the effects of digestate on cell proliferation. To this aim we used HT-29 human colon adenocarcinoma cells, grown in monolayers, as a model. Digested tomatoes were diluted (20 ml, 50 ml and 100 ml/l) in culture medium and added to the cells for different incubation times (24 h, 48 h and 72 h). Inhibition of cell growth by tomato digestate was dose-dependent and resulted from an arrest of cell cycle progression at the G0/G1 and G2/M phase and by apoptosis induction. A down-regulation of cyclin D1, Bcl-2 and Bcl-xl expression was observed. We also found that heat treatment of samples before digestion enhanced β-carotene release and therefore cell growth inhibition. To induce with purified β-carotene solubilised in tetrahydrofuran the same cell growth inhibition obtained with the tomato digestate, a higher amount of the carotenoid was necessary, suggesting that β-carotene micellarised during digestion is utilised more efficiently by the cells, but also that other tomato molecules, reasonably made available during digestion, may be present and cooperate with β-carotene in promoting cell growth arrest.
Turbulent Rayleigh–Bénard convection in a near-critical fluid by three-dimensional direct numerical simulation
Authors: ACCARY G. , BONTOUX P. , ZAPPOLI B.
Published: December 2008

This paper presents state of the art three-dimensional numerical simulations of the Rayleigh–Bénard convection in a supercritical fluid. We consider a fluid slightly above its critical point in a cube-shaped cell heated from below with insulated sidewalls; the thermodynamic equilibrium of the fluid is described by the van der Waals equation of state. The acoustic filtering of the Navier–Stokes equations is revisited to account for the strong stratification of the fluid induced by its high compressibility under the effect of its own weight. The hydrodynamic stability of the fluid is briefly reviewed and we then focus on the convective regime and the transition to turbulence. Direct numerical simulations are carried out using a finite volume method for Rayleigh numbers varying from 106 up to 108. A spatiotemporal description of the flow is presented from the convection onset until the attainment of a statistically steady state of heat transfer. This description concerns mainly the identification of the vortical structures in the flow, the distribution of the Nusselt numbers on the horizontal isothermal walls, the structure of the temperature field and the global thermal balance of the cavity. We focus on the influence of the strong stratification of the fluid on the penetrability of the convective structures in the core of the cavity and on its global thermal balance. Finally, a comparison with the case of a perfect gas, at the same Rayleigh number, is presented.
Water entry of small hydrophobic spheres
Authors: ARISTOFF JEFFREY M. , BUSH JOHN W. M.
Published: December 2008

We present the results of a combined experimental and theoretical investigation of the normal impact of hydrophobic spheres on a water surface. Particular attention is given to characterizing the shape of the resulting air cavity in the low Bond number limit, where cavity collapse is driven principally by surface tension rather than gravity. A parameter study reveals the dependence of the cavity structure on the governing dimensionless groups. A theoretical description based on the solution to the Rayleigh–Besant problem is developed to describe the evolution of the cavity shape and yields an analytical solution for the pinch-off time in the zero Bond number limit. The sphere's depth at cavity pinch-off is also computed in the low Weber number, quasi-static limit. Theoretical predictions compare favourably with our experimental observations in the low Bond number regime, and also yield new insight into the high Bond number regime considered by previous investigators. Discrepancies are rationalized in terms of the assumed form of the velocity field and neglect of the longitudinal component of curvature, which together preclude an accurate description of the cavity for depths less than the capillary length. Finally, we present a theoretical model for the evolution of the splash curtain formed at high Weber number and couple it with the underlying cavity dynamics.