bluuebunny/crossref_metadata_2025 huggingface dataset:
Major muscle systems in the larval caenogastropod, Ilyanassa obsoleta, display different patterns of development
Authors: Evans Carol C.E. , Dickinson Amanda J.G. , Croll Roger P.
Published: April 2009

This study describes the anatomical and developmental aspects of muscular development from the early embryo to competent larval stage in the gastropod Ilyanassa obsoleta. Staining of F‐actin revealed differential spatial and temporal patterns of several muscles. In particular, two major muscles, the larval retractor and pedal retractor muscles originate independently and display distinct developmental patterns similar to observations in other gastropod species. Additionally, together with the larval retractor muscle, the accessory larval muscle developed in the embryo at the trochophore stage. Therefore, both these muscles develop prior to ontogenetic torsion. The pedal retractor muscle marked the most abundant growth in the mid veliger stage. Also during the middle stage, the metapodial retractor muscle and opercular retractor muscle grew concurrently with development of the foot. We show evidence that juvenile muscles, such as the buccal mass muscle and siphon muscle develop initially during the late veliger stage. Collectively, these findings substantiate that larval myogenesis involves a complex sequence of events that appear evolutionary conserved within the gastropods, and set the stage for future studies using this model species to address issues concerning the evolution and eventual fates of larval musculature in molluscs. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.
Palmar bowing of the flexor retinaculum on wrist MRI correlates with subjective reports of pain in carpal tunnel syndrome
Authors: Tsujii Masaya , Hirata Hithoshi , Morita Akimasa , Uchida Atsumasa
Published: April 2009

Purpose

To investigate the utility of palmar bowing of the flexor retinaculum (PBFR) on magnetic resonance imaging (MRI) as an adjunct to presurgical evaluation of carpal tunnel syndrome (CTS).

Materials and Methods

The CTS group comprised 48 women with CTS diagnosed from clinical history, physical examination, and electrophysiological findings. Another 21 healthy women with no symptoms of CTS served as controls. The CTS group was divided into four subgroups based on symptom duration. CTS patients were preoperatively assessed for symptom severity using a Likert scale. In both groups, palmar bowing of the flexor retinaculum (PBFR) was measured on MRI. Furthermore, relationships with disease duration, subjective symptom severity, and electrophysiological findings were assessed in the CTS group.

Results

Although PBFR increased significantly in all CTS groups when compared to the control group, PBFR in patients who complained of severe pain tended to exceed that in patients with mild to moderate pain. Statistical analysis showed a positive correlation between PBFR and pain severity. In contrast, PBFR did not reflect median nerve function.

Conclusion

PBFR as seen on MRI seems to correlate significantly with patients' subjective reports of pain severity. J. Magn. Reson. Imaging 2009;29:1102–1105. © 2009 Wiley‐Liss, Inc.
In vivo quantification of femoral‐popliteal compression during isometric thigh contraction: Assessment using MR angiography
Authors: Brown Ryan , Nguyen Thanh D. , Spincemaille Pascal , Prince Martin R. , Wang Yi
Published: April 2009

Purpose

To quantify femoral‐popliteal vessel deformation during thigh contraction.

Materials and Methods

Eleven subjects underwent a magnetic resonance (MR) examination of the femoral‐popliteal vasculature on a 1.5 T system. A custom 3D balanced steady‐state free precession (SSFP) sequence was implemented to image a 15–20‐cm segment of the vasculature during relaxation and voluntary isometric thigh contraction. The arterial and venous lumina were outlined using a semiautomated method. For the artery, this outline was fit to an ellipse whose aspect ratio was used to describe arterial deformation, while venous deformation was characterized by its cross‐sectional area.

Results

Focal compression of the femoral‐popliteal artery during contraction was observed 94–143 mm superior to the condyle that corresponds to the distal adductor canal (AC) immediately superior to the adductor hiatus. This was illustrated by a significant reduction (P ≤ 0.05) in aspect ratio from 0.88 ± 0.06 during relaxation to 0.77 ± 0.09 during contraction. A negligible change in arterial aspect ratio was observed inferior to the AC and in the proximal AC. Similarly, venous area was dramatically reduced in the distal AC region during contraction.

Conclusion

Rapid 3D SSFP MR angiography of the femoral‐popliteal vasculature during thigh contraction demonstrated focal compression of the artery in the distal AC region. This may help explain the high stent failure rate and the high likelihood of atherosclerotic disease in the AC. J. Magn. Reson. Imaging 2009;29:1116–1124. © 2009 Wiley‐Liss, Inc.
Changes in hepatic venous morphology with cirrhosis on MRI
Authors: Zhang Yang , Zhang Xiao Ming , Prowda Joan C. , Zhang Hong Lei , Sant'Anna Henry Carolina , Shih George , Emond Jean C. , Prince Martin R.
Published: April 2009

Purpose

To identify changes in vascular morphology on magnetic resonance imaging (MRI) in patients with cirrhosis and to compare these findings to liver donors.

Materials and Methods

Patients undergoing liver transplantation with biopsy‐proven cirrhosis (n = 74) and liver donor candidates (n = 85) underwent dynamic gadolinium‐enhanced 3D MR at 1.5T. Vessel diameters were measured independently by three radiologists and features of cirrhosis were identified and correlated with cirrhosis.

Results

Hepatic veins were smaller in patients with cirrhosis (4.9, 4.5, and 5.0 mm for right, middle, and left vs. 9.9, 7.6, and 8.9 mm in donors, P ≪ 0.001) and were negatively correlated with cirrhosis (P < 0.001). Right hepatic vein (RHV) <5 mm diagnosed cirrhosis with 59% sensitivity and 99% specificity; the sensitivity and specificity were 88% and 85% for RHV <7 mm. Main portal vein was minimally larger in cirrhosis, 14 versus 12 mm (P < 0.001) in donors. Right portal veins were smaller in cirrhotic patients, 6.5 and 6.2 mm compared to 8.4 and 7.6 mm (P ≪ 0.001), respectively, in donors.

Conclusion

Vascular features of cirrhosis include small hepatic veins, minimally enlarged main portal vein, and small intrahepatic portal veins; these features may facilitate identification of cirrhosis. J. Magn. Reson. Imaging 2009;29:1085–1092. © 2009 Wiley‐Liss, Inc.
MRI and histological analysis of beta‐amyloid plaques in both human Alzheimer's disease and APP/PS1 transgenic mice
Authors: Meadowcroft Mark D. , Connor James R. , Smith Michael B. , Yang Qing X.
Published: April 2009

Purpose

To investigate the relationship between MR image contrast associated with beta‐amyloid (Aβ) plaques and their histology and compare the histopathological basis of image contrast and the relaxation mechanism associated with Aβ plaques in human Alzheimer's disease (AD) and transgenic APP/PS1 mouse tissues.

Materials and Methods

With the aid of the previously developed histological coil, T‐weighted images and R parametric maps were directly compared with histology stains acquired from the same set of Alzheimer's and APP/PS1 tissue slices.

Results

The electron microscopy and histology images revealed significant differences in plaque morphology and associated iron concentration between AD and transgenic APP/PS1 mice tissue samples. For AD tissues, T contrast of Aβ‐plaques was directly associated with the gradation of iron concentration. Plaques with significantly less iron load in the APP/PS1 animal tissues are equally conspicuous as the human plaques in the MR images.

Conclusion

These data suggest a duality in the relaxation mechanism where both high focal iron concentration and highly compact fibrillar beta‐amyloid masses cause rapid proton transverse magnetization decay. For human tissues, the former mechanism is likely the dominant source of R relaxation; for APP/PS1 animals, the latter is likely the major cause of increased transverse proton relaxation rate in Aβ plaques. The data presented are essential for understanding the histopathological underpinning of MRI measurement associated with Aβ plaques in humans and animals. J. Magn. Reson. Imaging 2009;29:997–1007. © 2009 Wiley‐Liss, Inc.
Early marker for Alzheimer's disease: Hippocampus T1rho (T1ρ) estimation
Authors: Haris Mohammad , McArdle Erin , Fenty Matthew , Singh Anup , Davatzikos Christos , Trojanowski John Q. , Melhem Elias R. , Clark Christopher M. , Borthakur Arijitt
Published: April 2009

Purpose

To evaluate the T1rho (T1ρ) MRI relaxation time in hippocampus in the brain of Alzheimer's disease (AD), mild cognitive impairment (MCI), and control, and to determine whether the T1ρ shows any significant difference between these cohorts.

Materials and Methods

With informed consent, AD (n = 49), MCI (n = 48), and age‐matched control (n = 31) underwent T1ρ MRI on a Siemens 1.5T Scanner. T1ρ values were automatically calculated from the left and right hippocampus region using in‐house developed software. Bonferroni post‐hoc multiple comparisons was performed to compare the T1ρ value among the different cohorts.

Results

Significantly higher T1ρ values were observed both in AD (P = 0.000) and MCI (P = 0.037) cohorts compared to control; also, the T1ρ in AD was significantly high over (P = 0.032) MCI. Hippocampus T1ρ was 13% greater in the AD patients than control, while in MCI it was 7% greater than control. Hippocampus T1ρ in AD patients was 6% greater than MCI.

Conclusion

Higher hippocampus T1ρ values in the AD patients might be associated with the increased plaques burden. A follow‐up study would help to determine the efficacy of T1ρ values as a predictor of developing AD in the control and MCI individuals. J. Magn. Reson. Imaging 2009;29:1008–1012. © 2009 Wiley‐Liss, Inc.
MRI methods for evaluating the effects of tyrosine kinase inhibitor administration used to enhance chemotherapy efficiency in a breast tumor xenograft model
Authors: Aliu S.O. , Wilmes L.J. , Moasser M.M. , Hann B.C. , Li K.‐L. , Wang D. , Hylton N.M.
Published: April 2009

Purpose

To evaluate whether quantitative MRI parameters are sensitive to the effects of the tyrosine kinase inhibitor gefitinib and can discriminate between two different treatment protocols.

Materials and Methods

Untreated mice with BT474 breast tumor xenografts were characterized in a preliminary study. Subsequently, tumor volume, apparent diffusion coefficient (ADC), transendothelial permeability (Kps), and fractional plasma volume (fPV) were measured in three groups of mice receiving: 1) control vehicle for 10 days, or gefitinib as 2) a single daily dose for 10 days or 3) a 2‐day pulsed dose.

Results

Gefitinib treatment resulted in significant tumor growth inhibition (pulsed: 439 ± 93; daily: 404 ± 53; control: 891 ± 174 mm3, P < 0.050) and lower cell density (pulsed: 0.15 ± 0.01, daily: 0.17 ± 0.01, control: 0.24 ± 0.01, P < 0.050) after 9 days. Tumor ADC increased in treated groups but decreased in controls (P > 0.050). Tumor Kps decreased with pulsed treatment but rebounded afterwards and increased with daily treatment (P > 0.050). Tumor fPV increased in both treated groups, decreasing afterwards with pulsed treatment (P > 0.050).

Conclusion

Quantitative MRI can provide a sensitive measure of gefitinib‐induced tumor changes, potentially distinguish between treatment regimens, and may be useful for determining optimal treatment scheduling for enhancing chemotherapy delivery. J. Magn. Reson. Imaging 2009;29:1071–1079. © 2009 Wiley‐Liss, Inc.
Comparison of spiral imaging and SENSE‐EPI at 1.5 and 3.0 T using a controlled cerebrovascular challenge
Authors: Winter Jeff D. , Poublanc Julien , Crawley Adrian P. , Kassner Andrea
Published: April 2009

Purpose

To quantitatively compare spiral imaging and sensitivity‐encoded‐echo‐planar‐imaging (SENSE‐EPI) methods for blood oxygen level‐dependent (BOLD) imaging using controlled changes in the end‐tidal partial pressure of CO2 (PetCO2) to provide a global BOLD response. Specifically, we examined susceptibility‐field‐gradient effects on the BOLD sensitivity throughout the brain.

Materials and Methods

We quantified cerebrovascular reactivity (CVR) using the BOLD response to cyclic changes in PetCO2 in five healthy volunteers at 1.5 and 3.0 T using spiral imaging and SENSE‐EPI. We compared the two techniques with respect to susceptibility‐induced signal dropout and CVR t‐statistic.

Results

Compared to spiral imaging, SENSE‐EPI significantly reduced the volume of signal dropout by 32 ± 18% at 3.0 T. In regions with large susceptibility gradients, SENSE‐EPI demonstrated a trend for a greater t‐statistic than spiral imaging, particularly at 3.0 T. However, no statistically significant between‐technique differences existed.

Conclusion

The results at 3.0 T suggest that, compared with spiral imaging, SENSE‐EPI reduces signal loss associated with susceptibility field gradients in affected regions without affecting BOLD sensitivity. This study also demonstrates a unique application of controlled PetCO2 changes to quantitatively compare BOLD techniques, which may be useful for the design of future fMRI studies. J. Magn. Reson. Imaging 2009;29:1206–1210. © 2009 Wiley‐Liss, Inc.
Effect of flip angle on volume flow measurement with nontriggered phase‐contrast MR: In vivo evaluation in carotid and basilar arteries
Authors: Tanaka Hisashi , Fujita Norihiko , Takahashi Hiroto , Sakai Mio , Nagao Taisuke , Murase Kenya , Nakamura Hironobu
Published: April 2009

Purpose

To evaluate the effect of flip angle on volume flow rate measurements obtained with nontriggered phase‐contrast magnetic resonance imaging (MRI) in vivo.

Materials and Methods

We prospectively measured volume flow rates of the bilateral internal carotid artery and the basilar artery with cine and nontriggered phase‐contrast MRI. For nontriggered phase‐contrast imaging, flip angles of 4, 15, 60, and 90° were used for 40 volunteers and of 8, 15, and 30° for 54 volunteers. Lumen boundaries were semiautomatically determined by pulsatility‐based segmentation using cine phase‐contrast MRI. Identical lumen boundaries were used for nontriggered phase‐contrast imaging.

Results

The ratio of volume flow rate obtained with nontriggered phase‐contrast imaging to that obtained with cine phase‐contrast imaging significantly increases with an increase in the flip angle. The mean ratios lie within a relatively narrow range of ±15% with a wide range of flip angles of 8–90°. As the flip angle increases, ghost artifacts become prominent and signal‐to‐noise and contrast‐to‐noise ratios increase.

Conclusion

Flip angles between 8 and 60° are most appropriate for nontriggered phase‐contrast MR measurements in the internal carotid and the basilar artery. J. Magn. Reson. Imaging 2009;29:1218–1223. © 2009 Wiley‐Liss, Inc.
Slice offset frequency and shim adjustment for interactive steady‐state free‐precession (SSFP) imaging
Authors: Graves Martin J. , Wong Pauline , Priest Andrew N. , Black Richard T. , Lomas David J.
Published: April 2009

Purpose

To devise a method allowing real‐time optimization of center frequency (CF) and shim for an interactive steady‐state free‐precession (SSFP) sequence by reformatting a previously acquired field map in the same orientation as the interactive acquisition.

Materials and Methods

Field maps were acquired in a rectangular parallel‐piped phantom and a normal volunteer. An SSFP sequence was modified to communicate the current slice offset and rotation to an external program that reformatted the field map into the same plane, calculated the CF and shim offsets, and passed them back to the sequence. CF offsets as a function of position for the phantom were compared with the scanner prescan‐determined offset.

Results

In the phantom, the CF measurements agreed with the scanner‐determined offsets. Bland‐Altman analysis showed a bias of −14 Hz (field map – prescan) and limits of agreement of −28 to 0 Hz. In the volunteer there was a qualitative improvement in image quality when using the optimized center frequencies and shims.

Conclusion

The proposed method demonstrates how CF and shim can be optimized for any interactively positioned slice, resulting in reduced off‐resonance artifacts. J. Magn. Reson. Imaging 2009;29:1230–1233. © 2009 Wiley‐Liss, Inc.
Regional atrophy of transcallosal prefrontal connections in cognitively normal APOE ϵ4 carriers
Authors: Filippini Nicola , Zarei Mojtaba , Beckmann Christian F. , Galluzzi Samantha , Borsci Genoveffa , Testa Cristina , Bonetti Matteo , Beltramello Alberto , Ghidoni Roberta , Benussi Luisa , Binetti Giuliano , Frisoni Giovanni B.
Published: April 2009

Purpose

To investigate the possible effect of the APOE ϵ4 allele on age‐related regional volume loss within the corpus callosum (CC) in healthy ϵ4 allele carriers compared with noncarriers.

Materials and Methods

A total of 211 subjects, ages 27 to 83 years, 51 ϵ4 carriers and 160 noncarriers underwent T1‐weighted MRI scan. All subjects had normal MRI scan and performed within normal range on a neuropsychological battery of tests. CC was segmented into seven functionally relevant regions using a previously published probabilistic map of the CC connectivity. We measured the volumes of the CC and its subregions. We used a regression model (with volumes as dependent and age as independent variables) and compared the slopes between carriers and noncarriers using an analysis of covariance model. We also carried out voxel‐based‐morphometry analysis to investigate the possible effect of the APOE ϵ4 gene on the gray matter.

Results

We found that the volume of the CC and all subregions decreased with increasing age in both groups. The slope was steeper in the APOE ϵ4 carriers compared withthe noncarriers particularly in the prefrontal region (P = 0.02). No gray matter differences were observed between the two groups.

Conclusion

APOE ϵ4 polymorphism is associated with accelerated age‐related volume loss in the prefrontal callosal tracts without gray matter loss. This result suggests the role of APOE ϵ4 in the brain aging by primarily affecting white matter structures particularly in the frontal lobe. J. Magn. Reson. Imaging 2009;29:1021–1026. © 2009 Wiley‐Liss, Inc.
Strain‐encoded cardiac MR during high‐dose dobutamine stress testing: Comparison to cine imaging and to myocardial tagging
Authors: Korosoglou Grigorios , Futterer Simon , Humpert Per M. , Riedle Nina , Lossnitzer Dirk , Hoerig Birgit , Steen Henning , Giannitsis Evangelos , Osman Nael F. , Katus Hugo A.
Published: April 2009

Purpose

To investigate regional strain response during high‐dose dobutamine stress cardiac magnetic resonance imaging (DS‐CMR) using myocardial tagging and Strain‐Encoded MR (SENC).

Materials and Methods

Stress induced ischemia was assessed by wall motion analysis, by tagged CMR and by SENC in 65 patients with suspected or known CAD who underwent DS‐CMR in a clinical 1.5 Tesla scanner. Coronary angiography deemed as the standard reference for the presence or absence of CAD (≥50% diameter stenosis) in all patients.

Results

SENC and conventional tagging detected abnormal strain response in six and five additional patients, respectively, who were missed by cine images and proved to have CAD by angiography (P < 0.05 for SENC versus cine, P = 0.06 for tagging versus cine and p = NS for SENC versus tagging). On a per‐vessel level, wall motion analysis on cine images showed high specificity (95%) but moderate sensitivity (70%) for the detection of CAD. Tagging and SENC yielded significantly higher sensitivity of 81% and 89%, respectively (P < 0.05 for tagging and P < 0.01 for SENC versus wall motion analysis, and p = NS for SENC versus tagging), while specificity was equally high (96% and 94%, respectively, P = NS for all).

Conclusion

Both the direct color‐coded visualization of strain on CMR images and the generation of additional visual markers within the myocardium with tagged CMR represent useful adjuncts for DS‐CMR, which may provide incremental value for the detection of CAD in humans. J. Magn. Reson. Imaging 2009;29:1053–1061. © 2009 Wiley‐Liss, Inc.
MRI‐based large deformation high dimensional mapping of the hippocampus in rats: Development and validation of the technique
Authors: Hogan R. Edward , Bouilleret Viviane , Liu Ying Rui , Wang Lei , Williams John P. , Jupp Bianca , Myers Damian , O'Brien Terence J.
Published: April 2009

Purpose

To report the detection of structural and functional biological changes in living animals using small animal in vivo MRI that complements traditional ex vivo histological techniques. We report the development and validation of the application of large deformation high dimensional mapping (HDM‐LD) segmentation for the hippocampus in the rat.

Materials and Methods

High resolution volumetric T2 weighted MRI images were acquired at 4.7 Tesla from six male in‐breed nonepileptic Wistar rats. Two HDM‐LD segmentations of the hippocampus (automated 1 and automated 2) were compared with the manual segmentations of two investigators who independently segmented the hippocampi (manual 1 and manual 2).

Results

The mean overlap for the hippocampi between automated 1 and automated 2 for the right hippocampi was 94.4% (SD 1.0) and for the left hippocampi was 94.3% (SD 2.5), while the mean overlap between automated 1 and manual 1 for the right hippocampi was 91.4% (SD 1.3) and for the left hippocampi was 91.9% (SD 1.4). Mean values for absolute differences for comparisons of all the segmentations were the following: automated 1 versus automated 2, 3.2% (SD 1.0); manual 1 versus manual 2 6.82% (SD 5.22); automated 1 versus manual 1 13.0% (SD 1.8).

Conclusion

HDM‐LD can be applied to obtain accurate and reproducible three‐dimensional segmentations of the hippocampus from rat MR images. HDM‐LD will be a useful tool for investigations of hippocampal structural changes in vivo in rat models of human disease. J. Magn. Reson. Imaging 2009;29:1027–1034. © 2009 Wiley‐Liss, Inc.
Signal fluctuations induced by non‐T1‐related confounds in variable TR fMRI experiments
Authors: Hu Shuowen , Olulade Olumide , Tamer Gregory G. , Luh Wen‐Ming , Talavage Thomas M.
Published: April 2009

Purpose

To assess and model signal fluctuations induced by non‐T1‐related confounds in variable repetition time (TR) functional magnetic resonance imaging (fMRI) and to develop a compensation procedure to correct for the non‐T1‐related artifacts.

Materials and Methods

Radiofrequency disabled volume gradient sequences were effected at variable offsets between actual image acquisitions, enabling perturbation of the measurement system without perturbing longitudinal magnetization, allowing the study of non‐T1‐related confounds that may arise in variable TR experiments. Three imaging sessions utilizing a daily quality assurance (DQA) phantom were conducted to assess the signal fluctuations, which were then modeled as a second‐order system. A modified projection procedure was implemented to correct for signal fluctuations arising from non‐T1‐related confounds, and statistical analysis was performed to assess the significance of the artifacts with and without compensation.

Results

Assessment using phantom data reveals that the signal fluctuations induced by non‐T1‐related confounds was consistent in shape across the phantom and well‐modeled by a second‐order system. The phantom exhibited significant spurious detections (at P < 0.01) almost uniformly across the central slices of the phantom.

Conclusion

Second‐order system modeling and compensation of non‐T1‐related confounds achieves significant reduction of spurious detection of fMRI activity in a phantom. J. Magn. Reson. Imaging 2009;29:1234–1239. © 2009 Wiley‐Liss, Inc.
A comprehensive analysis of changes in precipitation regime in Tuscany
Authors: Fatichi Simone , Caporali Enrica
Published: April 2009

The analysis of changes in precipitation is nowadays of great interest because rainfall space‐time distribution is considered one of the most important indexes in the natural climatic cycle. This study proposes an investigation of precipitation time series recorded in the region of Tuscany (Central Italy) in the period 1916–2003. Forty indexes are defined to evaluate changes in the precipitation patterns and trend detection is performed through statistical tests to assess the significance of temporal and spatial changes in the precipitation regime. The presented analysis does not show strong evidence of nonstationarity. A few indexes in a given number of stations of the analysed territory do show a slight trend, but the significance of those trends is lost once the multiple location testing issue is considered. The complexity of the climate in central Italy, i.e. the presence of numerous feedbacks might in fact distort or remove the consequences of global warming on the precipitation regime. Copyright © 2009 Royal Meteorological Society
Interdecadal variability of summer rainfall in Northwest China and its possible causes
Authors: Zhou Lian‐Tong , Huang Rong‐Hui
Published: April 2009

The present study investigates interdecadal variability of summer rainfall in Northwest China using station observations for the period 1951–2000 and the ERA‐40 reanalysis for the period 1958–2000. It is found that Northwest China summer rainfall experienced an obvious interdecadal increase around 1978. Analyses show that summer circulation, temperature and potential vorticity anomalies over Asia vary vastly before and after 1978. During the period 1978–2000, cyclonic and anti‐cyclonic circulation anomalies dominate over Northwest and North China, respectively. These are associated with the anomalous ascending motion over Northwest China, and their anomalous descending motion over North China. The temperature over Northwest China shows an obvious decrease at 300 hPa, but increase near the surface after 1978. This enhances convective instability, which contributes to the strengthening of ascent and the increase of summer rainfall in Northwest China during 1978–2000. Copyright © 2009 Royal Meteorological Society
Ultraviolet resonance Raman spectroscopy of locked single‐stranded oligo(dA) reveals conformational implications of the locked ribose in LNA
Authors: Konorov Stanislav O. , Georg Schulze H. , Addison Christopher J. , Haynes Charles A. , Blades Michael W. , Turner Robin F. B.
Published: April 2009

We report here the first UV resonance Raman spectroscopic (UVRRS) study on locked nucleic acid (LNA) oligomers. Locking a base in nucleic acid (NA) oligomers produces a conformational change in the glycosyl bond between backbone and base. We present evidence of this change in LNAs when compared to their natural analogs using UVRRS. Wavenumber downshifts and peak amplitude increases, especially of the ∼1481 cm−1 peak that is a spectral marker for part of the glycosyl bond, correlate with the fraction of locked bases when single‐stranded oligomers incorporating up to three locked bases were examined. By varying the position of the locked base within a fixed length sequence, we conclude that one, or at most two bases, on either side of the lock is affected. We further conclude from these data, and previously published reports, that the conformation of LNA is determined by imidazole–imidazole and pyrimidine–pyrimidine repulsion and imidazole–pyrimidine attraction in contrast to dispersion attraction‐dependent aggregation in the B conformation of DNA. Copyright © 2009 John Wiley & Sons, Ltd.
Resonance Raman spectra and excited state structural dynamics of ethylene trithiocarbonate in the A‐ and B‐band absorptions
Authors: Wang Huigang , Liu Bo , Zhao Yanying , Zheng Xuming
Published: April 2009

A‐ and B‐band resonance Raman spectra were acquired for ethylene trithiocarbonate in cyclohexane solution. The results indicate that the S3 state structural dynamics is mostly along vibrational motions of the CS stretch υ11, while the S4 state one has motions mainly via the SCS symmetric stretch υ18, CS stretch υ11, and the HCH rock + SCS antisymmetric stretch υ14 reaction coordinates. The very different excited state structural dynamics were briefly discussed in terms of vibronic couplings using local symmetry point group. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of enantioselective HPLC separation of structurally diverse compounds on chiral stationary phases with different teicoplanin coverage and distinct linkage chemistry
Authors: Honetschlägerová‐Vadinská Marie , Srkalová Simona , Bosáková Zuzana , Coufal Pavel , Tesarová Eva
Published: April 2009

Enantioseparation performance of two teicoplanin‐based chiral stationary phases, Chirobiotic T and Chirobiotic T2, with different teicoplanin coverage and distinct linkage chemistry was compared. Three structurally diverse groups of analytes, amino alcohols (β‐blockers), chlorophenoxypropionic acids, and branched‐chain amino acids, in various mobile phase compositions/separation modes were examined. The amino alcohols showed better enantioresolution on Chirobiotic T2 in reverse‐phase, hydrophilic interaction chromatography, and polar‐ionic mode separation systems. The best results with these analytes were obtained in the polar‐ionic mobile phase. In contrast, the chlorophenoxypropionic acids and the branched‐chain amino acids yielded an improved enantioresolution on the chiral stationary phase with lower amount of teicoplanin in the hydrophilic interaction chromatography system. The comparison of separation of the chlorophenoxypropionic acids enantiomers in the reverse‐phase and hydrophilic interaction chromatography environments showed completely opposite results. While better enantioresolution of chlorophenoxypropionic acids was achieved on Chirobiotic T2 in mobile phases with low methanol content, high methanol concentration was needed to reach baseline enantioseparation on Chirobiotic T.
A genome‐inspired DNA ligand for the affinity capture of insulin and insulin‐like growth factor‐2
Authors: Xiao Junfeng , Carter Jennifer A. , Frederick Kimberley A. , McGown Linda B.
Published: April 2009

The insulin‐linked polymorphic region (ILPR) of the human insulin gene contains tandem repeats of similar G‐rich sequences, some of which form intramolecular G‐quadruplex structures in vitro. Previous work showed affinity binding of insulin to an intramolecular G‐quadruplex formed by ILPR variant a. Here, we report on interactions of insulin and the highly homologous insulin‐like growth factor‐2 (IGF‐2) with ILPR variants a, h, and i. Circular dichroism indicated intramolecular G‐quadruplex formation for variants a and h. Affinity MALDI MS and surface plasmon resonance were used to compare protein capture and binding strengths. Insulin and IGF‐2 exhibited high binding affinity for variants a and h but not i, indicating the involvement of intramolecular G‐quadruplexes. Interaction between insulin and variant a was unique in the appearance of two binding interactions with KD ∼︁ 10–13 M and KD ∼︁ 10–7 M, which was not observed for insulin with variant h (KD ∼︁ 10–8 M) or IGF‐2 with either variant (KDs ∼︁ 10–9 M). The results provide a basis for the design of DNA binding ligands for insulin and IGF‐2 and support a new approach to discovery of DNA affinity binding ligands based on genome‐inspired sequences rather than the traditional combinatorial selection route to aptamer discovery.
Zinc peroxide precursor for ZnO clusters
Authors: Dmytruk A. , Dmitruk I. , Kasuya A.
Published: April 2009

Zinc peroxide is suggested as a new precursor for formation of zinc oxide clusters. (ZnO)n, n=1–100 clusters have been produced by laser ablation of bulk powder of zinc peroxide and studied by time‐of‐flight mass spectroscopy.
Mineral distribution in highly fluorotic and in normal teeth: A synchrotron microcomputer tomographic study
Authors: Neues F. , Klocke A. , Beckmann F. , Herzen J. , Loyola‐Rodriguez J.P. , Epple M.
Published: April 2009

A healthy and a fluorotic human molar tooth were studied by high‐resolution synchrotron microcomputer tomography (SRμCT) and compared with respect to their structure and mineral distribution. The teeth were measured in their full size, i.e. without introducing segmentation or cutting artefacts. Enamel and dentin were clearly separated on the basis of their different X‐ray absorption coefficient. No significant differences in the degree of mineralization were found between the healthy and the fluorotic tooth, except for a slightly rougher enamel surface of the fluorotic tooth.
On impurities and the internal structure in precipitates occurring during the precipitation of nanocrystalline calcium phosphate
Authors: Zyman Z. , Epple M. , Rokhmistrov D. , Glushko V.
Published: April 2009

Nanocrystalline calcium phosphate was precipitated at 20 °C from calcium nitrate and ammonium phosphate solutions at a pH of 9–11. The nature of the mass loss steps in thermogravimetry of the product was revealed by in‐situ mass spectrometry of released gases upon heating. Major amounts of nitrate‐containing impurities like NH4NO3 and Ca(NO3)2 were present which could only be removed by multiple washing with water. These impurities were not crystalline, but they were clearly detectable in the infrared spectrum. In conclusion, the high specific surface area of freshly precipitated calcium phosphate may cause the adsorption of considerable amounts of foreign compounds (molecules and ions) in the percent mass range.
Protective effects of C60 fullerenes on staurosporine‐, cytosine arabinoside‐ and hydrogen peroxide‐induced cell death of normal but not of transformed T lymphocytes
Authors: Palyvoda K. , Samoylenko A. , Drobot L. , Matyshevska O. , Scharff P.
Published: April 2009

C60 fullerenes are carbon nanospheres known to exert a protective activity in several models of apoptotic cell death. Both normal rat thymocytes and human T‐cell lymphoma Jurkat cells were treated with staurosporine, cytosine arabinoside and hydrogen peroxide as agents that trigger cell death. Activation of caspase‐3 as apoptosis marker was demonstrated in cells incubated for 4 h in the presence of these agents at concentrations causing 50 % cell viability reduction. Addition of C60 fullerenes (10‐5 M) protected normal T cells but not human T lymphoma cells from apoptosis induced either by staurosporine, cytosine arabinoside or hydrogen peroxide. These data demonstrate selectivity of fullerenes C60 biological effects in cultures of normal and transformed T cells.
Influence of grain size on mechanical and corrosion properties of magnesium alloy for medical implants
Authors: Kutniy K.V. , Papirov I.I. , Tikhonovsky M.A. , Pikalov A.I. , Sivtzov S.V. , Pirozhenko L.A. , Shokurov V.S. , Shkuropatenko V.A.
Published: April 2009

The microstructure, mechanical property and corrosion behavior of magnesium alloy WE43 (MgYNdZr alloy) in the environment simulating biological fluid were investigated. Samples of ultra‐fine‐grained magnesium alloy with high mechanical properties were obtained by methods of severe plastic deformation. Programmed plastic deformation was realized by two methods: extrusion alternating with upsetting at gradually lowering the temperature and equal‐channel angular pressing.
Electrostatic control of occupancy and valence selectivity in a charged nanometer‐sized cylindrical pore
Authors: Spohr E. , Sovyak E. , Trokhymchuk A. , Busath D.D.
Published: April 2009

Simple analytical calculations of the electrostatic energy for systems composed of positive charges confined to the axis of a negatively charged cylindrical pore are used to explore the role of electrostatic forces in the problems of ion permeation, ion occupancy and valence selectivity in biological ion channels. Considering the effect of finite length of the charged pore as an alternative to fixed charged residue representations, we show that ion occupancy and ion configurations in the pore are governed by two parameters: (i) the magnitude of the uniform surface charge density of the pore and (ii) the pore (diameter‐to‐length) aspect ratio through the interplay between favorable interaction of the mobile ions with the pore interior and unfavorable interaction among the ions themselves. The pore with an overall surface charge of ‐2e (representing a potassium channel) is found to favor occupancy by three K+ ions over two K+ ions at low aspect ratio but not at high. The pore with surface charge ‐4e (representing a calcium channel) favors occupancy by two lateral Ca2+ ions and one central Na+ ion over two symmetrically positioned Ca2+ ions at a low aspect ratio, but this preference is reversed at a higher aspect ratio. These results allow us to speculate that Ca2+ block of sodium current in the calcium channel is due to lower electrostatic energy for the Na+ ‐ Ca2+ ‐ Na+ configuration than for the Na+ ‐ Na+ ‐ Na+ configuration, and that the yet lower energy of the Ca2+ ‐ Ca2+ configuration would facilitate Ca2+ relief of Ca2+ block.
Peculiarities of nickel‐aluminium ferrites nanopowder structure
Authors: Kopayev A.V. , Ostafiychuk B.K. , Vylka I.Y. , Zadnipryannyy D.L.
Published: April 2009

The ferrites powders of the compound NiAltFe2‐tO4 were produced up to technology of sol‐gel autocombustion. In accordance with x‐ray defractional analysis data the powder particles’ size is 18–33 nanometers. The magnetic and electronic ferrites structure was researched with the help of XANES and Mössbauer spectroscopy methods. The iron ions valency is equal + 3. Magnetic penetrability depends upon the content of nickel ions in the tetrahedral lattice points. The calculation shows that while increasing the nickel concentration in the tetrahedral lattice points the constant of magnetoelastic anisotropy is growing.
Are multi‐resort ski conglomerates more efficient?
Authors: Falk Martin
Published: April 2009

This paper compares the efficiency of large ski resort conglomerates with independent ski resorts using data on four countries (Canada, France, United States, Switzerland). Using the stochastic frontier production approach, I find that ski resorts that are owned and managed by the Intrawest group are significantly more efficient than independent ski resorts. The efficiency gap is about nine percentage points on average. The remaining ski resort conglomerates (American Skiing, Vail Resorts Inc., and Compagnie des Alpes SA) do not operate more efficiently than independent ski resorts. Copyright © 2009 John Wiley & Sons, Ltd.
Micromechanical analysis of failure propagation in frictional granular materials
Authors: Tordesillas Antoinette , Shi Jingyu
Published: April 2009

The extent to which the evolution of instabilities and failure across multiple length scales can be reproduced with the aid of a bifurcation analysis is examined. We adopt an elastoplastic micropolar constitutive model, recently developed for dense cohesionless granular materials within the framework of thermomicromechanics. The internal variables and their evolution laws are conceived from a direct consideration of the dissipative mechanism of force chain buckling. The resulting constitutive law is cast entirely in terms of the particle scale properties. It thus presents a unique opportunity to test the potential of micromechanical continuum formulations to reproduce key stages in the deformation history: the development of material instabilities and failure following an initially homogeneous deformation. Progression of failure, initiating from frictional sliding and rolling at contacts, followed by the buckling of force chains, through to macroscopic strain softening and shear banding, is reproduced. Bifurcation point, marking the onset of shear banding, occurred shortly after the peak stress ratio. A wide range of material parameters was examined to show the effect of particle scale properties on the progression of failure. Model predictions on the thickness and angle of inclination of the shear band and the structural evolution inside the band, namely the latitudinal distribution of particle rotations and the angular distributions of contacts and the normal contact forces, are consistent with observations from numerical simulations and experiments. Copyright © 2009 John Wiley & Sons, Ltd.
An evaluation of nurse engagement in emancipatory practice development: The diary of a critical companion
Authors: Newman Claire , Cashin Andrew , Downie Amanda
Published: April 2009

There is a paucity of research in the area of nurse engagement in the process of practice development. Little is published about the sequencing of engagement with consent and pre‐measures in a research project. It has, however, been recognized that without engagement, development of one's practice, and subsequently health service change, would be minimal. This article reports on nurse engagement in the first six weeks of the implementation of a new model of care in two correctional service health care settings. Copyright © 2009 John Wiley & Sons, Ltd.
‘Teaching an old dog new tricks’: A practice development approach to organizational change in mental health
Authors: Lamont Scott , Walker Peter , Brunero Scott
Published: April 2009

Practice development is widely described as: ‘ways in which knowledge and skills development is used to provide better patient care’. This article will outline a mental health units approach and experience of implementing collaborative practice development processes which identify values and beliefs and enable the development of a framework of action to effect positive change. A qualitative participatory action research design was used to engage participants in exploring and critiquing relevant workplace culture issues. The project was divided into four chronological stages: values clarification; claims, concerns and issues; barriers, enablers and actions; and action planning. The results of this project highlight a number of issues for practice development approaches. We believe that these processes are easily transferable to other organizations within health care. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and characterization of novel thermoplastic poly(oligophosphazene‐urethane)s
Authors: Zhou Yubo , Huang Xiaobin , Tang Xiaozhen
Published: April 2009

BACKGROUND: Polyurethanes are some of the most popular polymers used in a variety of products, such as coatings, adhesives, flexible and rigid foams, elastomers, etc. Despite the possibility of tailoring their properties, polyurethanes suffer a serious disadvantage of poor thermal stability. Many attempts have been made in order to improve the thermal stability of polyurethanes.

RESULTS: A new hydroxyl‐terminated oligomer containing sulfone groups, 2,2‐bis(4‐hydroxy‐4,4‐sulfonyldiphoneloxy)tetraphenoxyoligocyclotriphosphazene (HSPPZ), was synthesized. HSPPZ was characterized using Fourier transform infrared (FTIR), NMR and gel permeation chromatography analyses. A series of novel thermoplastic poly(oligophosphazene‐urethane)s were then synthesized via the reaction of NCO‐terminated polyurethane prepolymer with HSPPZ containing chain‐extender diols. Their structure and properties were investigated using FTIR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X‐ray diffraction, water contact angle measurement and tensile measurements.

CONCLUSION: Compared to conventional thermoplastic polyurethanes, poly(oligophosphazene‐urethane)s exhibit better thermal stability, low‐temperature resistance and hydrophobicity, but their mechanical properties are slightly poorer. Copyright © 2009 Society of Chemical Industry
Transmission of polar substituent effects across the cubane ring system: 19F substituent chemical shifts (SCS) of 4‐substituted (X) cub‐1‐yl fluorides revisited
Authors: Adcock William
Published: April 2009

19F NMR shieldings of 4‐substituted (X) cub‐1‐yl fluorides (4) for a set of substituents (XH, NO2, CN, NC, CF3, COOH, F, Cl, HO, NH2, CH3, Si(CH3)3, Li, O− and NH) covering a wide range of electronic substituent effects were calculated using the DFT‐GIAO theoretical model. The level of theory, B3LYP/6‐311+G(2d,p), provided 19F substituent chemical shifts (SCS) in good agreement with experimental values where known. By means of NBO analysis, various molecular parameters were obtained from the optimized geometries. Linear regression analysis was employed to explore the relationship between the calculated 19F SCS and polar field, resonance and group electronegativity substituent constants (σF, σR and σx, respectively) and also the NBO derived molecular parameters (fluorine natural charges (Qn), electron occupancies on fluorine of lone pairs (nF) and occupation number of the CF antibonding orbital (σCF*)). The key determining parameters appear to be nF and σCF*(occup). Both factors are a function of the electrostatic field influence of the substituent (σF effect) but are counteractive in their influence on the shifts. No evidence for a significant resonance effect influence on the shifts could be identified. Copyright © 2009 John Wiley & Sons, Ltd.
PMMA‐based core‐shell nanoparticles with various PTFE cores
Authors: Kapeliouchko Valerj , Palamone Giovanna , Poggio Tiziana , Zuccheri Giampaolo , Passeri Rosita , Sparnacci Katia , Antonioli Diego , Deregibus Simone , Laus Michele
Published: April 2009

Polytetrafluoroethylene (PTFE) latices with spherical and rod‐like particles in the submicrometer size range, were employed as seeds in the emulsifier‐free methylmethacrylate (MMA) emulsion polymerization to obtain PTFE‐polymethylmethacrylate (PMMA) core‐shell nanoparticles. Stable latices were generally obtained. No residual PTFE was found at the end of the reaction. By appropriately choosing the ratio between MMA and PTFE in the reaction mixture, particles with predetermined size and monodisperse or narrow size distribution were prepared. The high structural regularity of the core‐shell samples allows the preparation of film with a periodic distribution of the cores thus ultimately leading to a well structured 2D colloidal crystal. A very peculiar crystallization behavior was observed because of the PTFE compartmentalization in the composite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2928–2937, 2009
Preparation of monodisperse nanoparticles containing poly(propylene imine)(NH2)32‐polystyrene
Authors: Liu Hu , Hu Xiaoxi , Wang Yingxi , Li Xiaoqin , Yi Changfeng , Xu Zushun
Published: April 2009

Polypropylenimine dendrimer (DAB‐Am‐32, generation 4.0) was converted into a macroinitiator DAB‐Am‐32‐Cl via reaction with 2‐chloropropionyl chloride. Monodisperse nanoparticles containing poly(propylene imine)(NH2)32‐polystyrene were prepared by emulsion atom transfer radical polymerization (ATRP) of styrene (St), using the DAB‐Am‐32‐Cl/CuCl/bpy as initiating system. The structure of macroinitiator was characterized by FTIR spectrum, 1H NMR, and 13C NMR. The structure of poly(propylene imine)(NH2)32‐polystyrene was characterized by FT‐IR spectrum and 1H NMR; the molecular weight and molecular weight distribution of poly(propylene imine)(NH2)32‐polystyrene were characterized by gel permeation chromatograph (GPC). The morphology, size and size distribution of the nanoparticles were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The effects of monomer/macroinitiator ratio and surfactant concentration on the size and size distribution of the nanoparticles were investigated. It was found that the diameters of the nanoparticles were smaller than 100 nm (30–80 nm) and monodisperse; moreover, the particle size could be controlled by monomer/macroinitiator ratios and surfactant concentration. With the increasing of the ratio of St/DAB‐Am‐32‐Cl, the number‐average diameter (Dn), weight‐average diameter (Dw) were both increased gradually. With enhancing the surfactant concentration, the measured Dh of the nanoparticles decreased, while the polydispersity increased. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2892–2904, 2009