bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiecho reconstruction for simultaneous water‐fat decomposition and T2* estimation
Authors: Yu Huanzhou , McKenzie Charles A. , Shimakawa Ann , Vu Anthony T. , Brau Anja C.S. , Beatty Philip J. , Pineda Angel R. , Brittain Jean H. , Reeder Scott B.
Published: September 2007

Purpose

To describe and demonstrate the feasibility of a novel multiecho reconstruction technique that achieves simultaneous water‐fat decomposition and T2* estimation. The method removes interference of water‐fat separation with iron‐induced T2* effects and therefore has potential for the simultaneous characterization of hepatic steatosis (fatty infiltration) and iron overload.

Materials and Methods

The algorithm called “T2*‐IDEAL” is based on the IDEAL water‐fat decomposition method. A novel “complex field map” construct is used to estimate both R2* (1/T2*) and local B0 field inhomogeneities using an iterative least‐squares estimation method. Water and fat are then decomposed from source images that are corrected for both T2* and B0 field inhomogeneity.

Results

It was found that a six‐echo multiecho acquisition using the shortest possible echo times achieves an excellent balance of short scan and reliable R2* measurement. Phantom experiments demonstrate the feasibility with high accuracy in R2* measurement. Promising preliminary in vivo results are also shown.

Conclusion

The T2*‐IDEAL technique has potential applications in imaging of diffuse liver disease for evaluation of both hepatic steatosis and iron overload in a single breath‐hold. J. Magn. Reson. Imaging 2007;26:1153–1161. © 2007 Wiley‐Liss, Inc.
Range of ventricular dimensions and function by steady‐state free precession cine MRI in repaired tetralogy of Fallot: Right ventricular outflow tract patch vs. conduit repair
Authors: Samyn Margaret M. , Powell Andrew J. , Garg Ruchira , Sena Laureen , Geva Tal
Published: September 2007

Purpose

To characterize the range of biventricular size and function evaluated by steady‐state free precession (SSFP) cine magnetic resonance (MR) in a large cohort of patients with repaired tetralogy of Fallot (TOF), and to compare these measurements in those with a right ventricular outflow tract (RVOT) patch vs. a right ventricle‐to‐pulmonary artery (RV‐PA) conduit.

Materials and Methods

Analysis of ventricular size and function in 300 consecutive examinations in patients with repaired TOF evaluated by SSFP cine MR.

Results

Of the 300 examinations performed in 256 patients, 69% had undergone repair with a RVOT patch and 31% with a RV‐PA conduit. Compared to patients with RV‐PA conduit, those with a RVOT patch had significantly more pulmonary regurgitation (PR) (38 ± 17 vs. 23 ± 16%, P < 0.0001), larger indexed RV end‐diastolic volume (154 ± 53 vs. 133 ± 51 mL/m2, P = 0.002), similar indexed end‐systolic volume (80 ± 39 vs. 74 ± 46 mL/m2, P = 0.31), higher ejection fraction (EF) (50 ± 9 vs. 47 ± 12%, P = 0.037), and lower mass‐to‐volume ratio (0.29 ± 0.08 vs. 0.36 ± 0.13, P < 0.0001). Pulmonary regurgitation fraction correlated positively with RV end‐diastolic volume index in the RVOT patch group (r = 0.51, P < 0.0001) but not in the RV‐PA conduit.

Conclusion

This study provides the range and distribution of biventricular size and function, and PR measured by MRI in a large contemporary cohort of patients with repaired TOF, and demonstrates important variations in RV mechanics between patients repaired with a RVOT patch and those with an RV‐PA conduit. J. Magn. Reson. Imaging 2007;26:934–940. © 2007 Wiley‐Liss, Inc.
Intercenter agreement of brain atrophy measurement in multiple sclerosis patients using manually‐edited SIENA and SIENAX
Authors: Jasperse Bas , Valsasina Paola , Neacsu Veronica , Knol Dirk L. , De Stefano Nicola , Enzinger Christian , Smith Stephen M. , Ropele Stefan , Korteweg Tijmen , Giorgio Antonio , Anderson Valerie , Polman Chris H. , Filippi Massimo , Miller David H. , Rovaris Marco , Barkhof Frederik , Vrenken Hugo
Published: September 2007

Purpose

To investigate intercenter agreement of brain volume (change) measurement in multiple sclerosis (MS) using structural image evaluation using normalization of atrophy (SIENA) and the cross‐sectional version of SIENA (SIENAX) with additional manual editing to correct for inadequate brain extraction.

Materials and Methods

Baseline and follow‐up T1‐weighted MR images of 20 MS patients were dispatched to five centers. Each center performed fully‐automated and manually‐edited analyses for SIENAX, yielding normalized brain volume (NBV), and SIENA, yielding percentage brain volume change (PBVC). Intercenter agreement was assessed with the concordance correlation coefficient (CCC).

Results

Intercenter agreement was perfect for fully automated NBV and PBVC (both CCC = 1.0), and remained substantial upon manual editing (CCC = 0.94 for NBV, CCC = 0.95 for PBVC). Mean NBV values for each center decreased significantly after manual editing (overall mean NBV = 1605.3 cm3 vs. 1651.1 cm3 without manual editing; t = –4.58, P < 0.001). Total variance in PBVC decreased significantly by a factor of 1.8 after manual editing (σ2 = 2.82 before, and σ2 = 1.54 after manual editing, P < 0.05).

Conclusion

Substantial intercenter agreement was found for manually‐edited SIENAX and SIENA, suggesting that measurements from multiple centers may be pooled. Manual editing reduces overestimation of NBV, and is likely to increase statistical power for PBVC. J. Magn. Reson. Imaging 2007;26:881–885. © 2007 Wiley‐Liss, Inc.
Evaluation of regional myocardial function using automated wall motion analysis of cine MR images: Contribution of parametric images, contraction times, and radial velocities
Authors: Kachenoura Nadjia , Redheuil Alban , Balvay Daniel , Ruiz‐Dominguez Cinta , Herment Alain , Mousseaux Elie , Frouin Frédérique
Published: September 2007

Purpose

To develop fast and robust procedures for a clinical evaluation of regional myocardial contractile function.

Materials and Methods

Parametric analysis of main motion was applied to steady‐state free‐precession (SSFP) cine MR images. From the time–signal intensity curve associated with each pixel, parametric maps of mean high and low amplitudes and transition times between muscle and cavity were automatically computed. Then, regional time to first contraction, Tfc, mean contraction time, Tmc and radial component of the endocardial velocity, Vm were estimated from these parametric maps and a user‐defined endocardial end‐diastolic contour. The method was applied to short‐axis slices in 22 subjects: eight controls, 13 myocardial infarctions (MIs), and one left bundle branch block (LBBB).

Results

Typical patterns of normality and pathology on parametric maps are indicated. For controls, the mean values ± standard deviations (SDs) of Tfc, Tmc, and Vm were: 70 ± 25 msec, 318 ± 43 msec, and 4.6 ± 1.8 cm second–1. An apex to base gradient of Tfc, a significant septal delay in Tfc and Tmc, and a decrease of Vm between the lateral and septal walls were observed. For MI, Tfc and Tmc increased and Vm decreased significantly in pathological segments. For LBBB, large delays were estimated in the septal wall.

Conclusion

The proposed method is promising for clinical assessment of regional wall contraction. J. Magn. Reson. Imaging 2007;26:1127–1132. © 2007 Wiley‐Liss, Inc.
Influence of inversion pulse type in assessing lung‐oxygen‐enhancement by centrically‐reordered non‐slice‐selective inversion‐recovery half‐Fourier single‐shot turbo spin‐echo (HASTE) sequence
Authors: Puderbach Michael , Ohno Yoshiharu , Kawamitsu Hideaki , Koyama Hisanobu , Takenaka Daisuke , Nogami Munenobu , Obara Makoto , Van Cauteren Marc , Kauczor Hans‐Ulrich , Sugimura Kazuro
Published: September 2007

Purpose

To demonstrate the influence of inversion pulse type and inversion time for assessment of oxygen‐enhancement on centrically‐reordered non‐slice‐selective inversion‐recovery (IR) half‐Fourier single‐shot turbo spin‐echo (HASTE) sequence.

Material and Methods

Phantoms with and without 100% oxygen and three healthy volunteers were studied with two‐dimensional (2D) centrically‐reordered non‐slice selective IR‐HASTE sequence with either composite or block inversion‐recovery pulse at increasing inversion times from 200 to 1800 msec. Signal‐to‐noise ratios (SNRs) of phantom, real signal differences, and relative enhancement ratios of lung parenchyma between oxygen‐enhanced and non‐oxygen‐enhanced MR images on composite and block pulse type were statistically compared at each TI.

Results

SNRs at TIs of 200 and 400 msec using the composite inversion pulse type were significantly lower than those with the block inversion pulse in the in vivo study (P < 0.05), although no significant differences were observed in the phantom study and in the in vivo study at inversion times greater than or equal to 600 msec. Real signal intensity (SI) differences at 400 and 600 msec of the composite inversion pulse type were significantly higher than those with the block inversion pulse type (P < 0.05). Relative enhancement ratio at 800 msec with the composite inversion pulse were significantly lower than that with the block inversion pulse (P < 0.05).

Conclusion

IR pulse type and inversion time have influence on assessment of oxygen‐enhancement by centrically‐reordered non‐slice‐selective IR‐HASTE sequence. J. Magn. Reson. Imaging 2007;26:1133–1138. © 2007 Wiley‐Liss, Inc.
STIR turbo SE MR imaging vs. coregistered FDG‐PET/CT: Quantitative and qualitative assessment of N‐stage in non‐small‐cell lung cancer patients
Authors: Ohno Yoshiharu , Koyama Hisanobu , Nogami Munenobu , Takenaka Daisuke , Yoshikawa Takeshi , Yoshimura Masahiro , Ohbayashi Chiho , Sugimura Kazuro
Published: September 2007

Purpose

To conduct a prospective comparison of the accuracy of short inversion time (TI) inversion‐recovery (STIR) turbo spin‐echo (SE) imaging and coregistered 2‐[fluorine‐18] fluoro‐2‐deoxy‐D‐glucose (FDG)–positron emission tomography (PET) with computed tomography (CT) (coregistered FDG‐PET/CT) to assess the N‐stage in non‐small‐cell lung cancer (NSCLC) patients.

Materials and Methods

A total of 115 consecutive NSCLC patients prospectively underwent CT, STIR turbo SE imaging, and FDG‐PET, as well as surgical and pathological examinations. All STIR turbo SE images were obtained with a 0.9% saline phantom, which was placed alongside the chest wall of each patient, and coregistered FDG‐PET/CTs were reconstructed using commercially available software. For quantitative assessments, the ratio of signal intensity (SI) of each lymph node to that of 0.9% saline phantom (lymph node‐saline ratio [LSR]) and maximal standardized uptake value (SUVmax) of each lymph node were calculated. Feasible threshold values were determined by using the receiver operating characteristic (ROC) curve‐based positive test, and diagnostic capabilities of N‐stage were compared by McNemar's test on a per patient basis.

Results

When feasible, threshold values were adopted, quantitative sensitivity (90.1%) and accuracy (92.2%) of STIR turbo SE imaging were significantly higher than those of quantitative and qualitative sensitivities (76.7% and 74.4%) and accuracies (83.5% and 82.6%) of coregistered FDG‐PET/CT on a per patient basis (P < 0.05).

Conclusion

STIR turbo SE imaging is at least as valid as coregistered FDG‐PET/CT for quantitative and qualitative assessment of the N‐stage for NSCLC patients. J. Magn. Reson. Imaging 2007;26:1071–1080. © 2007 Wiley‐Liss, Inc.
A practical method for 2D multiple‐animal MRI
Authors: Ramirez Marc S. , Bankson James A.
Published: September 2007

Purpose

To investigate practical methods for achieving routine simultaneous 2D MRI of multiple animals in large‐bore experimental scanners.

Materials and Methods

Three four‐element array geometries were compared against a standard single‐coil configuration in terms of image quality, ease of use, and data efficiency using a four‐channel, 4.7 T small animal imaging system.

Results

A linear arrangement of volume resonators permits unobstructed animal preparation and use of an imaging protocol that is almost identical to the single‐coil configuration without requiring any image correction or other additional postprocessing. Resulting in vivo images were visually indistinguishable from those acquired through the single‐coil configuration.

Conclusion

The efficiency of animal studies employing 2D MRI techniques can be substantially improved by using a linear array of commercially available resonators. J. Magn. Reson. Imaging 2007;26:1162–1166. © 2007 Wiley‐Liss, Inc.
MRI of early‐ and late‐stage arterial remodeling in a low‐level cholesterol‐fed rabbit model of atherosclerosis
Authors: Ronald John A. , Walcarius Rhonda , Robinson John F. , Hegele Robert A. , Rutt Brian K. , Rogers Kem A.
Published: September 2007

Purpose

To monitor early‐ and late‐stage arterial remodeling following low‐level cholesterol (CH) feeding in rabbits using a standardized MRI protocol.

Materials and Methods

New Zealand White rabbits were fed a CH diet (0.25% w/w) (n = 15) or normal chow (n = 6) and imaged either at 0, 2, 6, 8, and 11 months (“early‐stage”) or 12, 14, 16, 18, and 20 months (“late‐stage”). T2‐weighted fast‐spin‐echo images (≈200 μm in‐plane resolution) of aortic lesions were collected using either a 1.5 or 3.0T MR scanner interfaced with a customized surface RF coil. Luminal (LA), outer vessel wall boundary (OVBA), and vessel wall areas (VWA) were assessed.

Results

Among CH‐fed animals in the early‐stage group, increased VWA associated with decreased OVBA and a more pronounced decrease in LA was first detectable at 8 months. These changes became more evident between 8 and 11 months. In the late‐stage group, lesions continued to grow in response to CH‐feeding, as VWA significantly increased at regular 2‐month intervals. Beyond 16 months, signal intensity differences (reflecting increased lesion complexity) within the vessel wall were noted.

Conclusion

This often‐overlooked rabbit model combined with customized MR technology holds tremendous promise for studying the natural progression, regression, and remodeling of atherosclerotic lesions. J. Magn. Reson. Imaging 2007;26:1010–1019. © 2007 Wiley‐Liss, Inc.
A case of choledochocele mimicking choledocholithiasis on MR cholangiography: A new differential diagnosis of pseudo‐filling defect
Authors: Izumiya Masashi , Tamada Kiichi , Tomiyama Takeshi , Hanatsuka Kazunobu , Ohashi Akira , Sugano Kentaro
Published: September 2007

We present the case of a 79‐year‐old female with acute cholangitis and cholecystitis who presented with right upper quadrant pain. Thin‐collimation MR cholangiogram showed a filling defect measuring 1 cm, which was less prominent on single‐slab images. Endoscopy showed dynamic ballooning and collapsing of the ampulla of Vater, and a cholangiogram showed characteristic bulging at the distal common bile duct, which led to the diagnosis of choledochocele. It is important to differentiate choledochocele as a cause of filling defect of the lower common bile duct on the MR cholangiogram. J. Magn. Reson. Imaging 2007;26:1097–1100. © 2007 Wiley‐Liss, Inc.
“Pseudoseptum” of the uterine cervix on MRI
Authors: El Jack Amr K. , Siegelman Evan S.
Published: September 2007

Purpose

To determine the prevalence of a longitudinal “pseudoseptum” on T2‐weighted MR images within the cervices of women who do not have a uterine anomaly.

Materials and Methods

We reviewed 317 consecutive female pelvic MR examinations performed at a single institution over a four‐month period. All examinations included T2‐weighted sequences in at least two orthogonal planes. Of the 317 studies, 57 were excluded due to prior radical hysterectomy. Axial and coronal T2‐weighted images of the remaining 260 examinations were evaluated for the presence of a longitudinal low T2 signal intensity structure within the endocervical lumen that mimicked the appearance of a septum. Interpretations were performed independently by two MR radiologists and kappa analysis of interobserver agreement was performed.

Results

In 50 (19%) of the 260 women, both readers noted the presence of a pseudoseptum on at least one imaging plane. In 162 (62%), neither reader noted a pseudoseptum. Overall, there was 81% agreement between the readers. Kappa analysis yielded a value of 0.55, indicating a moderate degree of interobserver agreement beyond chance.

Conclusion

A pseudoseptum was depicted in 20% to 30% of women's cervices on T2‐weighted imaging. We hypothesize that chance long‐axis depiction of the endocervical folds can mimic a cervical septum. The presence of a pseudoseptum on MRI should be considered a normal finding and not a feature of a developmental anomaly of the uterus or cervix. J. Magn. Reson. Imaging 2007;26:963–965. © 2007 Wiley‐Liss, Inc.
Optimization and validation of a fully‐integrated pulse sequence for modified look‐locker inversion‐recovery (MOLLI) T1 mapping of the heart
Authors: Messroghli Daniel R. , Greiser Andreas , Fröhlich Mirko , Dietz Rainer , Schulz‐Menger Jeanette
Published: September 2007

Purpose

To optimize and validate a fully‐integrated version of modified Look‐Locker inversion‐recovery (MOLLI) for clinical single‐breathhold cardiac T1 mapping.

Materials and Methods

A MOLLI variant allowing direct access to all pulse sequence parameters was implemented on a 1.5T MR system. Varying four critical sequence parameters, MOLLI was performed in eight gadolinium‐doped agarose gel phantoms at different simulated heart rates. T1 values were derived for each variant and compared to nominal T1 values. Based on the results, MOLLI was performed in midcavity short‐axis views of 20 healthy volunteers pre‐ and post‐Gd‐DTPA.

Results

In phantoms, a readout flip angle of 35°, minimum TI of 100 msec, TI increment of 80 msec, and use of three pausing heart cycles allowed for most accurate and least heart rate–dependent T1 measurements. Using this pulse sequence scheme in humans, T1 relaxation times in normal myocardium were comparable to data from previous studies, and showed narrow ranges both pre‐ and postcontrast without heart rate dependency.

Conclusion

We present an optimized implementation of MOLLI for fast T1 mapping with high spatial resolution, which can be integrated into routine imaging protocols. T1 accuracy is superior to the original set of pulse sequence parameters and heart rate dependency is avoided. J. Magn. Reson. Imaging 2007;26:1081–1086. © 2007 Wiley‐Liss, Inc.
Method for automatic localization of MR‐visible markers using morphological image processing and conventional pulse sequences: Feasibility for image‐guided procedures
Authors: Busse Harald , Trampel Robert , Gründer Wilfried , Moche Michael , Kahn Thomas
Published: September 2007

Purpose

To evaluate the feasibility and accuracy of an automated method to determine the 3D position of MR‐visible markers.

Materials and Methods

Inductively coupled RF coils were imaged in a whole‐body 1.5T scanner using the body coil and two conventional gradient echo sequences (FLASH and TrueFISP) and large imaging volumes up to (300 mm3). To minimize background signals, a flip angle of ≈1° was used. Morphological 2D image processing in orthogonal scan planes was used to determine the 3D positions of a configuration of three fiducial markers (FMC). The accuracies of the marker positions and of the orientation of the plane defined by the FMC were evaluated at various distances rM from the isocenter.

Results

Fiducial marker detection with conventional equipment (pulse sequences, imaging coils) was very reliable and highly reproducible over a wide range of experimental conditions. For rM ≤ 100 mm, the estimated maximum errors in 3D position and angular orientation were 1.7 mm and 0.33°, respectively. For rM ≤ 175 mm, the respective values were 2.9 mm and 0.44°.

Conclusions

Detection and localization of MR‐visible markers by morphological image processing is feasible, simple, and very accurate. In combination with safe wireless markers, the method is found to be useful for image‐guided procedures. J. Magn. Reson. Imaging 2007;26:1087–1096. © 2007 Wiley‐Liss, Inc.
High‐resolution T1 mapping of the brain at 3T with driven equilibrium single pulse observation of T1 with high‐speed incorporation of RF field inhomogeneities (DESPOT1‐HIFI)
Authors: Deoni Sean C.L.
Published: September 2007

Purpose

To investigate an alternative approach to correct for flip angle inaccuracies in the driven equilibrium single pulse observation of T1 (DESPOT1) T1 mapping method.

Materials and Methods

While DESPOT1 is a robust method for rapid whole‐brain voxelwise mapping of the longitudinal relaxation time, the approach is inherently sensitive to inaccuracies in the transmitted flip angle, defined by the B1 field, which become more severe with increased field. Here we propose an extension of the DESPOT1 technique, involving the additional acquisition of an inversion‐prepared SPGR image alongside the conventional multiangle DESPOT1 data. From these combined data both B1 and T1 may be determined with high accuracy and precision. The method is evaluated at 3T with phantom and in vivo imaging experiments, with derived T1 estimates compared with values calculated from multiple inversion time inversion recovery data.

Results

The method provides robust correction of flip angle variations, with less than 5% error compared with reference values for T1 between 300 msec and 2500 msec.

Conclusions

The described approach, dubbed DESPOT1‐HIFI, permits whole‐brain T1 mapping at 3T, with 1 mm3 isotropic voxels, in a clinically feasible time (≈10 minutes) with T1 accuracy greater than 5% and with high precision. J. Magn. Reson. Imaging 2007;26:1106–1111. © 2007 Wiley‐Liss, Inc.
MR evidence of long T2 water in pathological white matter
Authors: Laule Cornelia , Vavasour Irene M. , Mädler Burkhard , Kolind Shannon H. , Sirrs Sandra M. , Brief Elana E. , Traboulsee Anthony L. , Moore G.R. Wayne , Li David K.B. , MacKay Alex L.
Published: September 2007

Purpose

To describe what, if any, specific long T2‐related abnormalities occur in the white matter of subjects with either phenylketonuria (PKU) or multiple sclerosis (MS).

Materials and Methods

The 48‐echo T2 relaxation data (maximum TE = 1.12 sec) were acquired from 15 PKU subjects, 20 MS subjects, and 15 healthy volunteers. Regions of interest were drawn in diffuse white matter hyperintensities (DiffWM), lesions, normal‐appearing white matter (NAWM), and normal white matter. Long T2 maps (200 msec < T2 < 800 msec) were created for each subject.

Results

A new water reservoir with a markedly prolonged T2 peak was identified in DiffWM and NAWM in 12 out of 15 subjects with PKU and a long T2 signal was also seen in 23/97 lesions in 50% of subjects with MS. Additionally, a long T2 component was observed in the corticospinal tracts of 10 healthy volunteers. The characteristics of the long T2 signal were unique for each subject group. Potential sources of this signal include vacuolation and increases in extracellular water.

Conclusion

This study supports the usefulness of increasing the data acquisition window of the multiecho T2 relaxation sequence to better characterize the T2 decay from pathological brain. J. Magn. Reson. Imaging 2007;26:1117–1121. © 2007 Wiley‐Liss, Inc.
Steady‐state free precession MRA of the renal arteries: Breath‐hold and navigator‐gated techniques vs. CE‐MRA
Authors: Maki Jeffrey H. , Wilson Gregory J. , Eubank William B. , Glickerman David J. , Pipavath Sudhakar , Hoogeveen Romhild M.
Published: September 2007

Purpose

To explore the use of breath‐hold and navigator‐gated noncontrast Steady State Free Precession (SSFP) MR angiography (MRA) protocols for the evaluation of renal artery stenosis (RAS).

Materials and Methods

Twenty patients referred to rule out RAS were imaged using two breath‐hold and one navigator‐gated SSFP MRA sequences. All patients underwent contrast‐enhanced MRA (CE‐MRA). Two radiologists evaluated all sequences both qualitatively (blur, artifacts, reader confidence) and quantitatively (maximum stenosis). Using CE‐MRA as truth, a receiver operating characteristics (ROC) curve was generated and a statistical analysis of navigator‐gated SSFP (Nav SSFP) was performed.

Results

Seven patients had >50% renal artery stenosis by CE‐MRA. Nav SSFP performed significantly better than either breath‐hold SSFP technique in terms of blur, artifacts, and reader confidence. Using a 50% threshold for stenosis, sensitivity for detecting RAS was 100%, with a specificity of 85% and a negative predictive value of 100%. The average mean stenosis difference between Nav SSFP and CE‐MRA was 9 ± 9%.

Conclusion

Nav SSFP outperformed breath‐hold SSFP in measures of image quality and reader confidence. Sensitivity and negative predictive value for detecting RAS with Nav SSFP was perfect, with an acceptable specificity of 85%. This suggests further study is warranted to evaluate Nav SSFP as a noncontrast screening technique for renal artery stenosis. J. Magn. Reson. Imaging 2007;26:966–973. © 2007 Wiley‐Liss, Inc.
Balancing fertility management and economics in organic field vegetable rotations
Authors: Schmutz Ulrich , Rayns Francis , Firth Chris
Published: September 2007

BACKGROUND: Organic field‐scale vegetables are among the most profitable enterprises in organic farming systems. They are also some of the most nutrient‐demanding crops, and many organic arable systems with field‐scale vegetables are stockless. Without livestock manure inputs, nutrient supply depends on fertility‐building crops, which generate only costs and no income. Different strategies of fertility management were compared on a central England research farm. Fertility management treatments consisted of different lengths of fertility building with green waste compost additions. Outputs and inputs in terms of nutrients and economics were monitored for 31 rotations during 1996–2002.

RESULTS: N, P and K rotational nutrient balances, as well as C inputs, showed a negative relationship with rotational gross margins. Variable and allocated fixed costs of fertility building were low, between 2 and 5% of variable costs (£0.5–2 ha−1 for 1 kg N ha−1 supplied to the rotation). The intensity of vegetable cropping in these rotations was moderate (25–40% vegetable crops in the rotation) and balancing of fertility management and economics was possible at this intensity without livestock manure or other permitted fertiliser additions.

CONCLUSION: Completely stockless systems (in analogy may be called vegan) are possible in organic vegetable production without compromising on fertility or economics. However, for a higher vegetable‐cropping intensity (up to 90%) a more sophisticated mix of short‐term fertility‐building and N‐trapping crops will be needed and such rotations may require further external addition of green waste or livestock manure. Copyright © 2007 Society of Chemical Industry
Effect of the stage of growth, wilting and inoculation in field pea (Pisum sativum L.) silages, III. Changes in the herbage and silage protein profiles
Authors: Cavallarin Laura , Borreani Giorgio
Published: September 2007

BACKGROUND: The effects of stage of growth, field wilting and inoculation with lactic acid bacteria (LAB) on the protein profile of herbage and silage were studied on field peas (Pisum sativum L.) harvested at four progressive morphological stages (end of flowering, I; beginning of pod filling, II; advanced pod filling, III; beginning of ripening, IV). The herbage was field wilted to a dry matter (DM) content around 330 g kg−1, for each stage of growth. The unwilted and wilted herbages were ensiled with (I) and without (C) a LAB inoculant.

RESULTS: As a result of the advancing maturity of the crop, the main protein component was Rubisco in the early stages and seed storage proteins in the more advanced stages, due to the redistribution of organic nitrogen during seed filling. Extensive degradation of Rubisco occurred in all the silages, without any effect of inoculation or wilting. A good preservation of the proteins was observed in stage IV for both unwilted and wilted silages, without further protein preservation due to LAB inoculation.

CONCLUSION: Protein protection observed in the more mature pea silage was due to the protein type and its localization and not to the level of DM at ensiling or to the inoculation. Copyright © 2007 Society of Chemical Industry
Distribution and biochemical composition of large and small seeds of soybean (Glycine max L.)
Authors: Guleria Shaileja , Sharma Sucheta , Gill Balwinder S , Munshi Satish K
Published: September 2007

BACKGROUND: The position of soybean seeds on the stem axis brings about differences in seed filling during seed development, which contributes to different seed size and results in determining the quality of seeds for food usage. The quality differences between the large and small seeds are reported.

RESULTS: The proportion of large seeds was higher at the apical portion while small seeds predominated at the basal portion of the soybean stem axis. The contents of lipids, starch, soluble sugars and soluble proteins were higher in large seeds as compared to those in small ones. The proportion of membrane lipid components, on a 10‐kernel basis, was higher in large seeds. The proportion of palmitate and oleate was also higher in large seeds. SDS‐PAGE analysis showed that glycinin (11S) proteins of 46 and 32 kDa were at higher concentrations, while 158 and 20 kDa were at lower concentration in large seeds in comparison to small seeds. Likewise, β‐conglycinins (7S) of 75, 62 and 46 kDa were higher in large seeds compared to small ones.

CONCLUSION: Segregating the seeds of apical from the basal portion of soybean plant at harvest is expected to improve the germination, growth, yield and food‐processing aspects. Copyright © 2007 Society of Chemical Industry
Backbone Dynamics of the Nafion Ionomer Studied by 19F‐13C Solid‐State NMR
Authors: Chen Qiang , Schmidt‐Rohr Klaus
Published: September 2007

The chain dynamics of a perfluorinated ionomer, Nafion®, have been studied by 19F and 19F‐13C solid‐state NMR at 295 K. The backbone of Nafion is essentially poly(tetrafluoroethylene) (PTFE), which was investigated for reference. Fast uniaxial rotations of the helical backbone were confirmed in PTFE and detected similarly in Nafion, though with a distribution of amplitudes. The rotations produce motionally averaged 19F‐13C dipolar couplings and chemical shift anisotropies (CSAs) that are linearly correlated. Additional narrowing of the CSAs indicated that the backbone axis in hydrated Nafion moves with an amplitude >15°. Motional amplitudes of various backbone and side‐branch sites were inferred from motionally averaged 19F CSA parameters measured with CSA recoupling. They increase with the distance from the branch point, e.g., to >25° in the center of the side branch. Implications for the chain and supramolecular structure of Nafion are discussed.

magnified image
Applicability of Statistical Theories of Network Formation
Authors: Dusˇek Karel
Published: September 2007

Summary: The basis of the statistical method of generation of branched and crosslinked structures as a Markov process is analyzed with special emphasis on the effect of differences in reactivities of functional groups. For irreversible reactions, it is important that the transition probabilities are calculated kinetically and that bonds once formed are not allowed to be reformed. The statistical methods are often a good approximation of real situation even if not all approximations used in the model are fulfilled. Cyclization is still a serious problem in modeling; For practical application it is recommended to rescale calculated ring‐free dependences against the experimental gel point.
Monte Carlo Simulations on Nanoparticles in Elastomers. Effects of the Particles on the Dimensions of the Polymer Chains and the Mechanical Properties of the Networks
Authors: Mark James E. , Abou‐Hussein Reda , Sen Taner Z. , Kloczkowski Andrzej
Published: September 2007

Summary: Reinforcement of elastomers is modeled using Monte Carlo simulations on rotational isomeric state chains, to characterize their spatial configurations in the vicinity of filler particles. The resulting filler‐perturbed distributions of the chain end‐to‐end distances are in agreement with experimental results gotten by neutron scattering. The use of these distributions in a standard molecular theory of rubberlike elasticity produces stress‐strain isotherms for elongation that are consistent with available experimental results.
Stress ‐ Optical Behaviour of Polymers
Authors: Ward Ian M.
Published: September 2007

Summary: The collaborative research between Stepto and colleagues at Manchester University and Ward and colleagues at Leeds University is discussed in terms of its general significance for understanding the development of molecular orientation which occurs during the stretching of polymers. Cross‐linked polyethylene and polyethylene terephthalate are chosen as the key examples, with particular reference to their stress optical behaviour. Infra‐red spectroscopy is shown to be a valuable tool to validate the methodology developed by Stepto and his colleagues for modelling the behaviour of rubber‐like networks.
Structure Development in Flexible Polyurethane Foam‐Layered Silicate Nanocomposites
Authors: Wilkinson Arthur N. , Fithriyah Nurul H. , Stanford John L. , Suckley Daniel
Published: September 2007

Summary: Polyurethane foam nanocomposites were formed via in‐situ copolymerisations, in which polyether polyol/water‐montmorillonite mixtures were reacted with toluene diisocyanate. The unmodified Na+‐ montmorillonite (MMT) was swollen in polyol/water using an ultrasound technique resulting in intercalated layers with increased basal spacings of 2.3 ± 0.1 nm. Measurements of quasi‐adiabatic temperature rise showed higher reaction rates as MMT loading increased from 0 to 10 wt.‐%. Forced‐adiabatic FTIR spectroscopy was used to determine the kinetics of both the copolymerisation and of the microphase separation between poly(ether‐urethane) soft segments and polyurea hard segments. The apparent microphase‐separation transition time decreased from 70 ± 3 to 42 ± 2 s upon addition of ≤10 wt.‐% MMT, but at reaction times >100 s there was significant retardation of the development of hydrogen bonding in the urea groups of the hard‐segment phase.
Comparative Study of Scattering and Osmotic Properties of Synthetic and Biopolymer Gels
Authors: Horkay Ferenc , Basser Peter J. , Hecht Anne‐Marie , Geissler Erik
Published: September 2007

Summary: The effect of monovalent/divalent cation exchange on the structure and osmotic properties of chemically cross‐linked polyacrylate and DNA gels swollen in near physiological salt solutions has been investigated. Both systems exhibit a reversible volume phase transition in the presence of calcium ions. The small‐angle neutron scattering spectra of these gels display qualitatively similar features. At low values of q surface scattering is observed, while in the intermediate q range the signal is characteristic of scattering from rod‐like elements. At high values of q the scattering intensity is governed by the local (short‐range) geometry of the polymer chains. The competition between monovalent and divalent cations has been studied by anomalous small‐angle X‐ray scattering (ASAXS). The ASAXS results reveal that the local concentration of the divalent counter‐ions in the vicinity of the polymer chains significantly exceeds that of the monovalent counter‐ions.
Comparison of Critical Exponents Determined by Rheology and Dynamic Light Scattering on Irreversible and Reversible Gelling Systems
Authors: Richter Sven
Published: September 2007

Summary:The sol‐gel transition of a radical chain cross‐linking copoly‐merization system [N‐vinylcaprolactam/2‐hydroxylethyl methacrylate/allyl‐methacrylate] and various thermoreversible gelling systems (mixtures made of xanthan gum and locust bean gum as well as gelatin) have been studied using in‐situ time‐resolved dynamic light scattering (DLS) and in‐situ rheology. A critical dynamical behavior was observed near the sol‐gel transition, which is characterized by the presence of a power‐law spectra in the time‐intensity correlation functiong2(t)−1 ∝ t−µand in the low‐amplitude oscillatory shear experimentG′(ω) ∝ G″(ω) ∝ ωn. A comparison of the obtained critical dynamical exponentsµandnwere made according to the theory by Doi and Onuki. This theory predicts a relation between these exponents, but up to now no detailed experimental comparison was done in the past. It was found that for all investigated systemsn > µ.
Autonomous Volume Transitions of a Polybase Triblock Copolymer Gel in a Chemically Driven pH‐Oscillator
Authors: Topham Paul D. , Howse Jonathan R. , Crook Colin J. , Gleeson Anthony J. , Bras Wim , Armes Steven P. , Jones Richard A. L. , Ryan Anthony J.
Published: September 2007

Summary:A pH‐responsive ABA triblock copolymer, comprising poly(methyl methacrylate)‐block‐poly(2‐(diethylamino)ethyl methacrylate)‐block‐poly(methyl methacrylate) [PMMA‐b‐PDEA‐b‐PMMA], has been cast into thin films with a well‐defined microstructure. Small Angle X‐ray Scattering (SAXS) and Atomic Force Microscopy (AFM) studies confirm that this copolymer forms a hydrogel consisting of PMMA spheres embedded within a polybase PDEA matrix, with the PMMA domains acting as physical cross‐links. The hydrogel has a pH‐reversible coil‐globule transition at around pH 4.5. This responsive physical property was exploited by immersing a sample of copolymer hydrogel in an aqueous solution containing a cyclic pH‐oscillating reaction, whereby the pH was continuously oscillated above and below the transition pH so as to induce autonomous volume transitions. The changes in microscopic and macroscopic length scales correlate closely during (de)swelling cycles, with affine behaviour occurring over five orders of magnitude.
Elastic Properties of Semi‐Flexible Chains and Networks
Authors: Cifra Peter , Bleha Tomáš
Published: September 2007

Summary: Elastic properties of noncharged polymers of stiffness ranging from flexible to rigid chains are determined from Monte Carlo simulations. The discrete wormlike chain (WLC) model with self‐interacting units is applied to chains of intermediate lengths. Elastic free energy and the force‐extension profiles of chains of variable stiffness are computed in an isometric ensemble. Occurrence of a plateau on the force‐extension curves at intermediate chain stiffness is noted. Qualitative differences are found between force profiles from simulations and from the standard (ideal) WLC model. The single‐chain data on influence of bending stiffness were employed in the three‐chain model of networks. Stress‐strain relations for networks show a highly nonlinear behavior with the marked strain‐stiffening effect.
Hyperbranched Aromatic Polyesters
Authors: Walczak Małgorzata , Lechowicz Jaromir B. , Galina Henryk
Published: September 2007

Summary: Having developed a theoretical model of hyperbranched polymerization involving AB2 and B2 monomers we present preliminary results of a test of its validity for the system consisting of 4,4‐bis(4‐hydroxyphenyl)pentanoic acid (AB2 monomer) and bisphenol A (B2 monomer). The monomers reacted at room temperature to yield the title hyperbranched polyesters. Diisopropylcarbodiimide (condensation water remover) along with an effective catalyst were used for that purpose. The total of AB2 monomer was introduced at once to a reactor containing B2 core monomer or it was divided into 3 or 5 equal portions and each of them introduced after the monomers previously present have reacted to a predetermined conversion. GPC measurements of the resulting molecular mass distribution gave inconclusive results because of poor reproducibility of polymer isolation/purification procedure and/or insufficient accuracy of GPC technique.
Deformation Studies on Polymer‐Clay Nanocomposite Gels
Authors: Shibayama Mitsuhiro , Miyazaki Sho , Endo Hitoshi , Karino Takeshi , Haraguchi Kazutoshi
Published: September 2007

Summary: The polymer‐clay nanocomposite gels (NC gels), developed by Haraguchi et al. (Adv. Mater., 2001), exhibit extraordinarily high mechanical properties, such as high elongations and high ultimate strengths. In order to understand the origin of these properties, contrast‐matched small‐angle neutron scattering (SANS) studies were carried out for stretched NC gels. It was found that (1) the scattering function for NC gels is simply given by a Lorentz function, a function for semidilute polymer solutions, without a characteristic cross‐link inhomogeneity term for polymer gels, and (2) the unique mechanical properties are ascribed to its network structure, i.e., long polymer chains connected by “plane” cross‐links.
2‐Dimensional Network Formation from a Graft Copolymer at the Air‐Water Interface
Authors: de Samaniego M. Simon Saenz , Miller A.F.
Published: September 2007

Summary: The UV induced cross‐linking of a well defined graft copolymer polynorbornene‐g‐poly(ethylene oxide) at the air‐water interface has been investigated. Network formation has been monitored qualitatively by observing changes in surface pressure with UV exposure time working under constant area conditions. Surface film concentration has been used as the design parameter to manipulate initial film organization, and consequently position of the functional groups. Exposure of the copolymer film to UV light at different surface concentrations in the liquid condensed region shows the closer the molecules pack together the faster the cross‐linking reaction, while no cross‐linking occurs when the molecules are far apart in the liquid expanded state.
Characterization of Composite Networks Made of Type I Collagen, Hyaluronic Acid and Decorin
Authors: Lélu Sylvie , Pluen Alain
Published: September 2007

Summary: To ultimately assess the ability of macromolecular medicines e.g. liposomes, non viral gene delivery systems, to penetrate one of the least studied physiological barriers, the extracellular matrix (ECM), composite networks made of different ECM components i.e. type I collagen, hyaluronic acid and a proteoglycan, decorin, were prepared. These composite networks were characterized by rheology, Confocal Reflection Microscopy, Fluorescence Recovery After Photobleaching and Transmission Electron Microscopy. While being at the low end of its physiological concentration, collagen appears to be the backbone of the composite networks as it provides the elastic modulus. On the other hand, 15 kDa and 1.1 MDa hyaluronic acid, when present at physiological levels interpenetrate the collagen network. When approaching their overlap concentration, hyaluronic acid chains lead to an increase of the population of collagen fibrils. Finally, while decorin increased the population of fibrils in pure collagen networks, its role in presence of hyaluronic acid remains unclear as it does not alter the diameter of fibrils nor their population.
One‐ and Two‐Component Bottle‐Brush Polymers: Simulations Compared to Theoretical Predictions
Authors: Hsu Hsiao‐Ping , Paul Wolfgang , Binder Kurt
Published: September 2007

Scaling predictions for bottle‐brush polymers with a rigid backbone and flexible side chains under good solvent conditions are discussed and their validity is assessed by a comparison with Monte Carlo simulations of a simple lattice model. It is shown that typically only a rather weak stretching of the side chains is realized, and then the scaling predictions are not applicable. Also two‐component bottle brush polymers are considered, where two types (A,B) of side chains are grafted, assuming that monomers of different kind repel each other. In this case, variable solvent quality is allowed. Theories predict “Janus cylinder”‐type phase separation along the backbone in this case. The Monte Carlo simulations, using the pruned‐enriched Rosenbluth method (PERM) give evidence that the phase separation between an A‐rich part of the cylindrical molecule and a B‐rich part can only occur locally. The correlation length of this microphase separation can be controlled by the solvent quality. This lack of a phase transition is interpreted by an analogy with models for ferromagnets in one space dimension.

magnified image
Macromol. Theory Simul. 7/2007
Authors: Hsu Hsiao‐Ping , Paul Wolfgang , Binder Kurt
Published: September 2007

Cover: The picture on the cover shows a large crowded bottle‐brush polymer (top left) with anisotropic excluded volume scaling (top right) and a bottle brush copolymer (bottom right) exhibiting local phase separation showing 1d correlation length behavior (bottom left). Further details can be found in the article by H.‐P. Hsu*, W. Paul, and K. Binder on page 660.
An inherited disorder characterized by repeated episodes of bilateral ballism: A case report
Authors: Kakinuma Hiroaki , Hori Ariyuki , Itoh Masatsune , Nakamura Tsuneyuki , Takahashi Hiroaki
Published: September 2007

This case report describes two siblings with a dyskinetic form of cerebral palsy who had repeated episodes of fever‐induced bilateral ballistic movements. The boy and his sister experienced the first episodes during early childhood. The movements developed over several hours and required rapid intervention. Electroencephalograms during the attacks showed no paroxysms, and brain magnetic resonance imaging scans revealed no lesions. The brother died of acute renal failure at age 5 due to rhabdomyolysis after his fifth episode of prolonged bilateral ballistic movements. This is the first report of an inherited disorder characterized by repeated episodes of violent movements. © 2007 Movement Disorder Society
Compartmental loss of striatal medium spiny neurons in multiple system atrophy of parkinsonian type
Authors: Sato Kenta , Kaji Ryuji , Matsumoto Sadayuki , Nagahiro Shinji , Goto Satoshi
Published: September 2007

Topographical or compartmental involvement of the putamen and caudate nucleus has not been fully elucidated in multiple system atrophy predominantly presenting with Parkinsonism (MSA‐P). We carried out immunohistochemical studies using antibodies to calbindin (CALB) and calcineurin (CaN) as neurochemical markers for striatal medium spiny neurons. We found that in the caudal and dorsolateral putamen, the area most affected in MSA‐P, the medium spiny neurons positive for CALB were severely depleted, while CaN‐positive neurons were relatively spared in a mosaic pattern. In the dorsal caudate nucleus, an area less affected in MSA, residual CALB‐positive neurons exhibited a compartmentalized distribution that corresponded with the striosomal arrangement visualized by Met‐enkephalin immunostaining. Our findings suggest that there is a compartmental difference in the susceptibility of striatal medium spiny neurons to neurodegeneration in MSA‐P. © 2007 Movement Disorder Society
Skin vasodilator response to local heating in multiple system atrophy
Authors: Yamanaka Yoshitaka , Asahina Masato , Mathias Christopher J. , Akaogi Yuichi , Koyama Yu , Hattori Takamichi
Published: September 2007

Local heating of nonglabrous skin increases skin blood flow (SkBF) in two phases. The initial peak (P1) is mediated by a sensory‐axon reflex and the plateau phase (P2) by local production of substances such as nitric oxide. We evaluated the SkBF response to local heating in 15 multiple system atrophy (MSA) patients with autonomic failure and 12 age‐matched healthy controls. The mean ratio of SkBF at P1 to that at baseline (SkBFP1/SkBFbase ratio) in MSA was significantly lower than that in controls (P < 0.01). The mean ratio of SkBF at P2 seemed to be slightly reduced in the MSA patients, compared with controls, although there was no significant difference. The P1 phase is thought to be mediated by a sensory‐axon reflex modulated by sympathetic nerve activity. These findings are indicative of the skin sympathetic vasomotor dysfunction in MSA. © 2007 Movement Disorder Society