bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuropathological features of multiple system atrophy with cognitive impairment
Authors: Asi Y. T. , Ling Helen , Ahmed Z. , Lees A. J. , Revesz T. , Holton J. L.
Published: April 2014

Cognitive impairment (CI) is an exclusion criterion for the diagnosis of multiple system atrophy (MSA), according to the second consensus statement. This view was recently challenged by patients with pathologically confirmed MSA who were reported to have dementia. With an aim to investigate the pathological substrate of CI in MSA, quantitative assessment of the glial and neuronal cytoplasmic inclusions and semiquantitative assessment of neuronal loss in the cortical and limbic regions was performed. No differences in the severity of these MSA‐related pathological findings were identified between nine MSA cases with CI and nine MSA cases with normal cognition. Alzheimer's‐related pathological changes, cerebral amyloid angiopathy, and cerebrovascular disease did not differ between the two MSA groups. MSA‐specific α‐synuclein and secondary pathological conditions were not more severe in MSA cases with CI, suggesting that although CI may be intrinsic to the MSA disease process, further investigation into the pathological basis of cognitive impairment in MSA is warranted. © 2014 International Parkinson and Movement Disorder Society
Sensory tricks and brain excitability in cervical dystonia: A transcranial magnetic stimulation study
Authors: Amadio Stefano , Houdayer Elise , Bianchi Francesca , Tesfaghebriel Tekle Habtom , Urban Ivan Pietro , Butera Calogera , Guerriero Roberta , Cursi Marco , Leocani Letizia , Comi Giancarlo , Del Carro Ubaldo
Published: April 2014

Background

Sensory tricks such as touching the face with fingertips often improve cervical dystonia [CD]. This study is to determine whether sensory tricks modulate motor cortex excitability, assessed by paired‐pulse transcranial magnetic stimulation [p‐pTMS].

Methods

Eight patients with rotational CD underwent p‐pTMS, at rest and when the sensory trick was applied. To test intracortical inhibition [ICI] and facilitation [ICF], the amplitude ratio between conditioned and unconditioned cortical motor evoked potentials was measured at several interstimulus intervals (ISI 1, 3, 15, and 20 ms) and compared with controls mimicking patients' sensory tricks.

Results

At rest, a significant ICF enhancement was found at ISIs 15 through 20 in patients compared with controls, whereas no significant ICI changes were observed. Sensory tricks significantly reduced the abnormal ICF in patients and did not induce any change in controls.

Conclusions

In our CD patients, sensory tricks seem to improve dystonia through an inhibitory effect on motor cortex excitability. © 2014 International Parkinson and Movement Disorder Society
The distribution of lymph nodes and their nutrient vessels in the groin region: An anatomic study for design of the lymph node flap
Authors: Zhang Han , Chen Weiwei , Mu Lan , Chen Ru , Luan Jie , Mu Dali , Liu Chunjun , Xin Minqiang
Published: April 2014

Background

The groin lymph node flap transfer has been used for treatment of extremity lymphedema. The design of this flap is based on the superficial circumflex iliac artery/vein (SCIA/V), or superficial inferior epigastric artery/vein (SIEA/V). The purpose of this study is to delineate the distribution of lymph nodes in the groin area and their relationship to inguinal vessels by the use of multidirector‐row CT angiography (MDCTA).

Methods

MDCTA was performed in 52 patients who underwent the deep inferior epigastric perforator (DIEP) flap or transverse rectus abdominis musculocutaneous (TRAM) flap for breast reconstruction. The MDCTA data were used to analyze the locations of lymph nodes and their adjacent vascular vessels. The groin region was divided into the superior lateral (I), superior medial (II), inferior lateral (III), and inferior medial (IV) quadrants based on the point where SCIV joined into great saphenous vein. The number of lymph nodes in each of the four quadrants was counted and the dominant vessels were observed.

Results

The mean number of lymph nodes in quadrants I–IV were 3.3 ± 1.6, 2.0 ± 1.2, 1.5 ± 1.3, and 1.9 ± 1.4, respectively. The difference between the four quadrants was statistically significant (P < 0.001). In quadrant I, the appearance rate of SCIA was 100% while SIEA was 6.6%. In quadrant II, no SCIA was observed but the appearance rate of SIEA was 78.0%. There were neither SCIA nor SIEA observed in quadrants III and IV.

Conclusions

The superior lateral quadrant of the groin region was found to have the most lymph nodes. The superficial circumflex iliac vessels are the major sources for blood supply to this region. The findings from this study provide evidence for the clinical design of the lymph node flap from the groin area. © 2014 Wiley Periodicals, Inc. Microsurgery 34:558–561, 2014.
Median nerve fascicle transfer versus ULNAR nerve fascicle transfer to the biceps motor branch in C5‐C6 and C5‐C7 brachial plexus injuries: Nonrandomized prospective study of 23 consecutive patients
Authors: Cho Alvaro Baik , Paulos Renata Gregorio , de Resende Marcelo Rosa , Kiyohara Leandro Yoshinobu , Sorrenti Luiz , Wei Teng Hsiang , Bolliger Neto Raul , Mattar Rames
Published: April 2014

The purpose of this study was to observe whether the results of the median nerve fascicle transfer to the biceps are equivalent to the classical ulnar nerve fascicle transfer, in terms of elbow flexion strength and donor nerve morbidity. Twenty‐five consecutive patients were operated between March 2007 and July 2013. The patients were divided into two groups. In Group 1 (n = 8), the patients received an ulnar nerve fascicle transfer to the biceps motor branch. In Group 2 (n = 15), the patients received a median nerve fascicle transfer to the biceps motor branch. Two patients with follow‐up less than six months were excluded. Both groups were similar regarding age (P = 0.070), interval of injury (P = 0.185), and follow‐up period (P = 0.477). Elbow flexion against gravity was achieved in 7 of 8 (87.5%) patients in Group 1, versus 14 of 15 (93.3%) patients in Group 2 (P = 1.000). The level of injury (C5‐C6 or C5‐C7) did not affect anti‐gravity elbow flexion recovery in both the groups (P = 1.000). It was concluded that the median nerve fascicle transfer to the biceps is as good as the ulnar nerve fascicle transfer, even in C5‐C7 injuries. © 2014 Wiley Periodicals, Inc. Microsurgery 34:511–515, 2014.
SAR reduction in 7T C‐spine imaging using a “dark modes” transmit array strategy
Authors: Eryaman Yigitcan , Guerin Bastien , Keil Boris , Mareyam Azma , Herraiz Joaquin L. , Kosior Robert K. , Martin Adrian , Torrado‐Carvajal Angel , Malpica Norberto , Hernandez‐Tamames Juan A. , Schiavi Emanuele , Adalsteinsson Elfar , Wald Lawrence L.
Published: April 2014

Purpose

Local specific absorption rate (SAR) limits many applications of parallel transmit (pTx) in ultra high‐field imaging. In this Note, we introduce the use of an array element, which is intentionally inefficient at generating spin excitation (a “dark mode”) to attempt a partial cancellation of the electric field from those elements that do generate excitation. We show that adding dipole elements oriented orthogonal to their conventional orientation to a linear array of conventional loop elements can lower the local SAR hotspot in a C‐spine array at 7 T.

Methods

We model electromagnetic fields in a head/torso model to calculate SAR and excitation B1+ patterns generated by conventional loop arrays and loop arrays with added electric dipole elements. We utilize the dark modes that are generated by the intentional and inefficient orientation of dipole elements in order to reduce peak 10g local SAR while maintaining excitation fidelity.

Results

For B1+ shimming in the spine, the addition of dipole elements did not significantly alter the B1+ spatial pattern but reduced local SAR by 36%.

Conclusion

The dipole elements provide a sufficiently complimentary B1+ and electric field pattern to the loop array that can be exploited by the radiofrequency shimming algorithm to reduce local SAR. Magn Reson Med 73:1533–1539, 2015. © 2014 Wiley Periodicals, Inc.
Inter‐echo variance as a weighting factor for multi‐channel combination in multi‐echo acquisition for local frequency shift mapping
Authors: Liu Junmin , Rudko David A. , Gati Joseph S. , Menon Ravi S. , Drangova Maria
Published: April 2014

Purpose

To develop and evaluate a local frequency shift (LFS) mapping method specifically designed for multi‐echo acquisitions and multi‐channel receive coils.

Methods

The proposed method uses the pixel‐by‐pixel inter‐echo variance (IEV) as a weighting factor during channel‐combination. Five healthy volunteers were scanned at 7 T. The IEV‐weighted method was quantitatively compared to established (adaptive and Hermitian product) channel‐combination methods with respect to IEV of LFS over the entire brain.

Results

In all experiments, the IEV‐weighted method generated LFS maps free of artifacts caused by unwrapping errors. Based on measurements of the inter‐echo frequency variance throughout the whole brain, the IEV‐weighted method produced the lowest variation and the best contrast at the edge of the brain.

Conclusion

The primary finding of the present study is that accurate LFS maps are achievable if the data from each channel is processed independently prior to combination followed by a weighted combination using IEV as the weighting term. The software is freely available to the scientific community. Magn Reson Med 73:1654–1661, 2015. © 2014 Wiley Periodicals, Inc.
Parallel imaging with phase scrambling
Authors: Zaitsev Maxim , Schultz Gerrit , Hennig Juergen , Gruetter Rolf , Gallichan Daniel
Published: April 2014

Purpose

Most existing methods for accelerated parallel imaging in MRI require additional data, which are used to derive information about the sensitivity profile of each radiofrequency (RF) channel. In this work, a method is presented to avoid the acquisition of separate coil calibration data for accelerated Cartesian trajectories.

Methods

Quadratic phase is imparted to the image to spread the signals in k‐space (aka phase scrambling). By rewriting the Fourier transform as a convolution operation, a window can be introduced to the convolved chirp function, allowing a low‐resolution image to be reconstructed from phase‐scrambled data without prominent aliasing. This image (for each RF channel) can be used to derive coil sensitivities to drive existing parallel imaging techniques. As a proof of concept, the quadratic phase was applied by introducing an offset to the x2 − y2 shim and the data were reconstructed using adapted versions of the image space–based sensitivity encoding and GeneRalized Autocalibrating Partially Parallel Acquisitions algorithms.

Results

The method is demonstrated in a phantom (1 × 2, 1 × 3, and 2 × 2 acceleration) and in vivo (2 × 2 acceleration) using a 3D gradient echo acquisition.

Conclusion

Phase scrambling can be used to perform parallel imaging acceleration without acquisition of separate coil calibration data, demonstrated here for a 3D‐Cartesian trajectory. Further research is required to prove the applicability to other 2D and 3D sampling schemes. Magn Reson Med 73:1407–1419, 2015. © 2014 Wiley Periodicals, Inc.
Optimized saturation pulse train for human first‐pass myocardial perfusion imaging at 7T
Authors: Tao Yuehui , Hess Aaron T. , Keith Graeme A. , Rodgers Christopher T. , Liu Alexander , Francis Jane M. , Neubauer Stefan , Robson Matthew D.
Published: April 2014

Purpose

To investigate whether saturation using existing methods developed for 3T imaging is feasible for clinical perfusion imaging at 7T, and to propose a new design of saturation pulse train for first‐pass myocardial perfusion imaging at 7T.

Methods

The new design of saturation pulse train consists of four hyperbolic‐secant (HS8) radiofrequency pulses, whose peak amplitudes are optimized for a target range of static and transmit field variations and radiofrequency power deposition restrictions measured in the myocardium at 7T. The proposed method and existing methods were compared in simulation, phantom, and in vivo experiments.

Results

In healthy volunteer experiments without contrast agent, average saturation efficiency with the proposed method was 97.8%. This is superior to results from the three previously published methods at 86/95/90.8%. The first series of human first‐pass myocardial perfusion images at 7T have been successfully acquired with the proposed method.

Conclusion

Existing saturation methods developed for 3T imaging are not optimal for perfusion imaging at 7T. The proposed new design of saturation pulse train can saturate effectively, and with this method first‐pass myocardial perfusion imaging is feasible in humans at 7T. Magn Reson Med 73:1450–1456, 2015. © 2014 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance.
Using dynamic contrast‐enhanced MRI to quantitatively characterize maternal vascular organization in the primate placenta
Authors: Frias Antonio E. , Schabel Matthias C. , Roberts Victoria H. J. , Tudorica Alina , Grigsby Peta L. , Oh Karen Y. , Kroenke Christopher D.
Published: April 2014

Purpose

The maternal microvasculature of the primate placenta is organized into 10–20 perfusion domains that are functionally optimized to facilitate nutrient exchange to support fetal growth. This study describes a dynamic contrast‐enhanced magnetic resonance imaging method for identifying vascular domains and quantifying maternal blood flow in them.

Methods

A rhesus macaque on the 133rd day of pregnancy (G133, term = 165 days) underwent Doppler ultrasound procedures, dynamic contrast‐enhanced magnetic resonance imaging and Cesarean‐section delivery. Serial T1‐weighted images acquired throughout intravenous injection of a contrast reagent bolus were analyzed to obtain contrast reagent arrival time maps of the placenta.

Results

Watershed segmentation of the arrival time map identified 16 perfusion domains. The number and location of these domains corresponded to anatomical cotyledonary units observed following delivery. Analysis of the contrast reagent wave front through each perfusion domain enabled determination of volumetric flow, which ranged from 9.03 to 44.9 mL/s (25.2 ± 10.3 mL/s). These estimates are supported by Doppler ultrasound results.

Conclusions

The dynamic contrast‐enhanced magnetic resonance imaging analysis described here provides quantitative estimates of the number of maternal perfusion domains in a primate placenta and estimates flow within each domain. Anticipated extensions of this technique are to the study placental function in non‐human primate models of obstetric complications. Magn Reson Med 73:1570–1578, 2015. © 2014 Wiley Periodicals, Inc.
Algebraic reconstruction technique for parallel imaging reconstruction of undersampled radial data: Application to cardiac cine
Authors: Li Shu , Chan Cheong , Stockmann Jason P. , Tagare Hemant , Adluru Ganesh , Tam Leo K. , Galiana Gigi , Constable R. Todd , Kozerke Sebastian , Peters Dana C.
Published: April 2014

Purpose

To investigate algebraic reconstruction technique (ART) for parallel imaging reconstruction of radial data, applied to accelerated cardiac cine.

Methods

A graphics processing unit (GPU)‐accelerated ART reconstruction was implemented and applied to simulations, point spread functions and in 12 subjects imaged with radial cardiac cine acquisitions. Cine images were reconstructed with radial ART at multiple undersampling levels (192 Nr × Np = 96 to 16). Images were qualitatively and quantitatively analyzed for sharpness and artifacts, and compared to filtered back‐projection, and conjugate gradient SENSE.

Results

Radial ART provided reduced artifacts and mainly preserved spatial resolution, for both simulations and in vivo data. Artifacts were qualitatively and quantitatively less with ART than filtered back‐projection using 48, 32, and 24 Np, although filtered back‐projection provided quantitatively sharper images at undersampling levels of 48‐24 Np (all P < 0.05). Use of undersampled radial data for generating auto‐calibrated coil‐sensitivity profiles resulted in slightly reduced quality. ART was comparable to conjugate gradient SENSE. GPU‐acceleration increased ART reconstruction speed 15‐fold, with little impact on the images.

Conclusion

GPU‐accelerated ART is an alternative approach to image reconstruction for parallel radial MR imaging, providing reduced artifacts while mainly maintaining sharpness compared to filtered back‐projection, as shown by its first application in cardiac studies. Magn Reson Med 73:1643–1653, 2015. © 2014 Wiley Periodicals, Inc.
Visualization of oxidative stress in ex vivo biopsies using electron paramagnetic resonance imaging
Authors: Gustafsson Håkan , Hallbeck Martin , Lindgren Mikael , Kolbun Natallia , Jonson Maria , Engström Maria , de Muinck Ebo , Zachrisson Helene
Published: April 2014

Purpose

The purpose of this study was to develop an X‐Band electron paramagnetic resonance imaging protocol for visualization of oxidative stress in biopsies.

Methods

The developed electron paramagnetic resonance imaging protocol was based on spin trapping with the cyclic hydroxylamine spin probe 1‐hydroxy‐3‐methoxycarbonyl‐2,2,5,5‐tetramethylpyrrolidine and X‐Band EPR imaging. Computer software was developed for deconvolution and back‐projection of the EPR image. A phantom containing radicals of known spatial characteristic was used for evaluation of the developed protocol. As a demonstration of the technique electron paramagnetic resonance imaging of oxidative stress was performed in six sections of atherosclerotic plaques. Histopathological analyses were performed on adjoining sections.

Results

The developed computer software for deconvolution and back‐projection of the EPR images could accurately reproduce the shape of a phantom of known spatial distribution of radicals. The developed protocol could successfully be used to image oxidative stress in six sections of the three ex vivo atherosclerotic plaques.

Conclusions

We have shown that oxidative stress can be imaged using a combination of spin trapping with the cyclic hydroxylamine spin probe cyclic hydroxylamine spin probe 1‐hydroxy‐3‐methoxycarbonyl‐2,2,5,5‐tetramethylpyrrolidine and X‐Band EPR imaging. A thorough and systematic evaluation on different types of biopsies must be performed in the future to validate the proposed technique. Magn Reson Med 73:1682–1691, 2015. © 2014 Wiley Periodicals, Inc.
T1ρ mapping for the evaluation of high intensity focused ultrasound tumor treatment
Authors: Hectors Stefanie J. C. G. , Moonen Rik P. M. , Strijkers Gustav J. , Nicolay Klaas
Published: April 2014

Purpose

This study was aimed to assess the effects of High Intensity Focused Ultrasound (HIFU) thermal ablation on tumor T1ρ.

Methods

In vivo T1ρ measurements of murine tumors at various spin‐lock amplitudes (B1 = 0–2000 Hz) were performed before (n = 13), directly after (n = 13) and 3 days (n = 7) after HIFU treatment. T2 maps were obtained from the measurements at B1 = 0 Hz.

Results

Average tumor T1ρ distributions at the different experimental time points showed a shift toward lower T1ρ values after HIFU for all spin‐lock amplitudes, which became larger with increasing spin‐lock amplitude at 3 days after treatment. Statistical analysis confirmed a significant effect of spin‐lock amplitude on the average change in T1ρ (ΔT1ρ) as compared to baseline at 3 days after HIFU. At 3 days after treatment, ΔT1ρ values at B1 above 100 Hz were significantly lower (more negative) than at B1 = 0 Hz (T2).

Conclusion

Significant changes in tumor T1ρ were observed after HIFU treatment. These T1ρ changes were distinctly more pronounced than HIFU‐induced changes in T2. The results indicate that T1ρ imaging is sensitive to HIFU‐induced tissue changes and may thus be a suitable MR method for the evaluation of HIFU treatment. Magn Reson Med 73:1593–1601, 2015. © 2014 Wiley Periodicals, Inc.
Axonal dysfunction, dysmyelination, and conduction failure in hereditary neuropathy with liability to pressure palsies
Authors: Farrar Michelle A. , Park Susanna B. , Krishnan Arun V. , Kiernan Matthew C. , Lin Cindy S.‐Y.
Published: April 2014

Introduction: Patients with hereditary neuropathy with liability to pressure palsies (HNPP) manifest with episodes of focal paresis when exposed to mechanical stress, although the basis for vulnerability to conduction block remains relatively unexplained. Methods: Axonal excitability techniques were utilized to provide insights into pathophysiological mechanisms in 13 HNPP patients, stimulating median motor and sensory axons at the wrist. Results: In HNPP, distal latencies were prolonged, and motor and sensory amplitudes were reduced. Threshold was increased. Depolarizing and hyperpolarizing electrotonus was greater, and resting current–threshold slope was reduced. There were greater threshold changes in superexcitability, and refractoriness was decreased. Conclusions: Taken together, excitability testing in patients with HNPP established axonal hyperpolarization in both motor and sensory axons that may be attributable to changes in nerve architecture. In turn, the hyperpolarized resting membrane potential in HNPP may be a major predisposing factor for development of conduction block with mechanical stresses. Muscle Nerve 49: 858–865, 2014
EMG processing to interpret a neural tension‐limiting mechanism with fatigue
Authors: La Delfa Nicholas J. , Sutherland Chad A. , Potvin Jim R.
Published: April 2014

Introduction: Surface electromyography (sEMG) amplitude increases with constant muscle tension during fatiguing sub‐maximum efforts. The purpose of this study was to determine if extreme highpass filtering and/or autoregressive whitening would result in a more consistent sEMG‐to‐moment ratio than a standard bandpass filter (20–500 Hz) during repeated, dynamic maximal efforts of the quadriceps. Methods: We collected sEMG and knee extensor moment from 16 participants during the concentric and eccentric phases of repeated, maximal knee extensor efforts. Results: The alternative processing methods provided more consistent vastus medialis and lateralis sEMG‐to‐moment ratios. A neural tension‐limiting mechanism appeared to exist and was magnified during the eccentric phase, particularly with fatigue. Conclusions: There appears to be a difference in how the central nervous system controls concentric and eccentric efforts as the quadriceps fatigues, and this is more apparent with the alternative EMG processing methods we used. Muscle Nerve 50: 384–392, 2014
Comparing axonal excitability in past polio to amyotrophic lateral sclerosis
Authors: Liang Christina , Ng Karl
Published: April 2014

Introduction: Poliomyelitis causes selective destruction of anterior horn cells and usually has a stable disease course post‐infection. We assessed the excitability characteristics in patients with a stable course after past poliomyelitis and compared them with changes described in amyotrophic lateral sclerosis (ALS). Methods: The excitability characteristics of motor and sensory nerves were studied in 10 subjects with stable past poliomyelitis. Results: Motor rheobase was increased, but there were no significant changes in strength–duration properties or depolarizing threshold electrotonus, as have been seen in previous studies of ALS. Conclusions: There is minimal change in axonal excitability properties in patients with stable past poliomyelitis. The results may signify sufficient compensation in the stable state of the disease. Increased subexcitability in 1 subject with demonstrable hyperexcitability may represent compensation for increased ectopic activity rather than a different process in surviving motor neurons. Muscle Nerve 50: 602–604, 2014
Assessment of quadriceps muscle inactivation with a new electrical stimulation paradigm
Authors: Wellauer Vanessa , Morf Claudia , Minetto Marco A. , Place Nicolas , Maffiuletti Nicola A.
Published: April 2014

Introduction: In this study we evaluated the validity of garment‐based quadriceps stimulation (GQS) for assessment of muscle inactivation in comparison with femoral nerve stimulation (FNS). Methods: Inactivation estimates (superimposed doublet torque), self‐reported discomfort, and twitch and doublet contractile properties were compared between GQS and FNS in 15 healthy subjects. Results: Superimposed doublet torque was significantly lower for GQS than for FNS at 20% and 40% maximum voluntary contraction (MVC) (P < 0.01), but not at 60%, 80%, and 100% MVC. Discomfort scores were systematically lower for GQS than for FNS (P < 0.05). Resting twitch and doublet peak torque were lower for GQS, and time to peak torque was shorter for GQS than for FNS (P < 0.01). Conclusions: GQS can be used with confidence for straightforward evaluation of quadriceps muscle inactivation, whereas its validity for assessment of contractile properties remains to be determined. Muscle Nerve 51: 117–124, 2015
Motor nerve conduction study and muscle strength in newly diagnosed poems syndrome
Authors: Liu Mingsheng , Zou Zhangyu , Guan Yuzhou , Li Jian , Zhou Daobin , Cui Liying
Published: April 2014

Introduction: Mixed demyelination and axonal loss are electrophysiological features of polyneuropathy, organomegaly, endocrinopathy, M‐protein, and skin changes (POEMS) syndrome. It is unclear whether the demyelination and axonal loss occur concurrently. Methods: Electromyography was performed in 37 patients with newly diagnosed POEMS syndrome. Compound muscle action potential (CMAP) amplitude, distal motor latency, motor conduction velocity (MCV), and spontaneous activity were collected. Muscle strength was measured according to the Medical Research Council (MRC) scale. Results: MCV decreased in all nerves with decreased CMAP amplitude and in 93% of nerves with normal amplitude. CMAP amplitude decreased in 54% of nerves with decreased MCV and was normal in all nerves with normal MCV. MCV deceased in 95% of nerves with normal MRC. Abnormal spontaneous activity was detected in 32% of upper limb muscles. Conclusions: Demyelination may be the main manifestation in POEMS neuropathy at an early stage, and axonal loss may be secondary to demyelination as the disease progresses. Muscle Nerve 51: 19–23, 2015
Balance and coordination training and endurance training after nerve injury
Authors: Bonetti Leandro Viçosa , Schneider Ana Paula Krauthein , Barbosa Silvia , Ilha Jocemar , Faccioni‐Heuser Maria Cristina
Published: April 2014

Introduction: Different rehabilitation treatments have proven useful in accelerating regeneration. Methods: After sciatic nerve crush in rats, we tested balance and coordination training (BCT) and endurance training (ET) through sensorimotor tests and analyzed nerve and muscle morphology. Results: After BCT and ET, rats performed better in sensorimotor tests than did non‐trained animals. However, only BCT maintained sensorimotor function during training. Furthermore, BCT and ET produced significantly larger muscle area than in non‐trained animals. Conclusions: These findings indicate that BCT and ET, when initiated in the early phase after sciatic nerve injury, improve morphological properties of the soleus muscle and sciatic nerve, but only the task‐oriented BCT maintained sensorimotor function. The success of rehabilitative strategies appears to be highly task‐specific, and strategies that stimulate sensory pathways are the most effective in improving balance and/or coordination parameters. Muscle Nerve 51: 83–91, 2015
Distinguishing neuromuscular disorders based on the passive electrical material properties of muscle
Authors: Li Jia , Jafarpoor Mina , Bouxsein Mary , Rutkove Seward B.
Published: April 2014

Introduction: The passive electrical properties of muscle, including conductivity and permittivity and their directional dependence, may be altered in neuromuscular disease; however, the character of these alterations is unknown. Methods: Fifteen wild‐type mice, 13 amyotrophic lateral sclerosis mice, 9 muscular dystrophy (mdx) mice, and 15 mice with induced disuse atrophy were euthanized, and the gastrocnemius was excised. A 50‐kHz current was applied immediately to the ex vivo muscle, and its material properties were calculated. Results: The disease groups showed distinct material property values [F(12, 119) = 14.6, P < 0.001] according to MANOVA. Post‐hoc tests confirmed that differences existed between all 4 groups. They were most pronounced in the mdx mice, which had markedly increased conductivity. Direction‐dependent properties of current flow also were significantly different among the groups (P < 0.001). Conclusions: These data confirm that the inherent passive electrical properties of muscle differ by disease type. We anticipate that similar data could eventually be obtained via surface measurements, providing an innovative approach to muscle disease diagnosis. Muscle Nerve 51: 49–55, 2015
Cover Picture: Conformational Dynamics of DNA G‐Quadruplex in Solution Studied by Kinetic Capillary Electrophoresis Coupled On‐line with Mass Spectrometry (ChemistryOpen 2/2014)
Authors: Mironov Gleb G. , Okhonin Victor , Khan Nasrin , Clouthier Christopher M. , Berezovski Maxim V.
Published: April 2014

No Abstract
Triggering receptor expressed on myeloid cells‐1 (TREM‐1) improves host defence in pneumococcal pneumonia
Authors: Hommes Tijmen J , Hoogendijk Arie J , Dessing Mark C , van't Veer Cornelis , Florquin Sandrine , Colonna Marco , de Vos Alex F , van der Poll Tom
Published: April 2014

Streptococcus (S.) pneumoniae is a common Gram‐positive pathogen in community‐acquired pneumonia and sepsis. Triggering receptor expressed on myeloid cells‐1 (TREM‐1) is a receptor on phagocytes known to amplify inflammatory responses. Previous studies showed that TREM‐1 inhibition protects against lethality during experimental Gram‐negative sepsis. We here aimed to investigate the role of TREM‐1 in an experimental model of pneumococcal pneumonia, using TREM‐1/3‐deficient (Trem‐1/3–/–) and wild‐type (Wt) mice. Additionally ex vivo responsiveness of Trem‐1/3–/– neutrophils and macrophages was examined. S. pneumoniae infection resulted in a rapid recruitment of TREM‐1‐positive neutrophils into the bronchoalveolar space, while high constitutive TREM‐1 expression on alveolar macrophages remained unchanged. TREM‐1/3 deficiency led to increased lethality, accompanied by enhanced growth of S. pneumoniae at the primary site of infection and increased dissemination to distant organs. Within the first 3–6 h of infection, Trem‐1/3–/– mice demonstrated a strongly impaired innate immune response in the airways, as reflected by reduced local release of cytokines and chemokines and a delayed influx of neutrophils. Trem‐1/3–/– alveolar macrophages produced fewer cytokines upon exposure to S. pneumoniae in vitro and were less capable of phagocytosing this pathogen. TREM‐1/3 deficiency did not influence neutrophil responsiveness to S. pneumoniae. These results identify TREM‐1 as a key player in protective innate immunity during pneumococcal pneumonia, most likely by enhancing the early immune response of alveolar macrophages. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Regulatory and logistical issues influencing access to antineoplastic and supportive care medications for children with cancer in developing countries
Authors: Wiernikowski John T. , MacLeod Stuart ,   for The Working Group on Essential Medicines of the Pediatric Oncology in Developing Countries committee of SIOP
Published: April 2014

Globally there are numerous impediments, both logistical, regulatory and more recently global drug shortages, hindering pediatric access to therapeutic drugs of all types. Efforts to reduce barriers are ongoing and are especially important in low and middle income countries and for children requiring treatment of conditions such as those encountered in pediatric oncology characterized by the risk of life threatening treatment failures. Progress has been made through the efforts of the World Health Organization and regulators in the US and Europe to encourage the development of therapeutic agents for use in pediatrics and measures taken have fostered the availability of stronger pediatric data to guide therapeutic decisions. Nonetheless, pharmaceuticals remain a global commodity, subject to regulation by the World Trade Organization and this has often had detrimental effects in low and middle income countries. This article emphasizes the need for closer international collaboration to address the barriers currently impeding access to antineoplastic and supportive care medicines for children. Pediatr Blood Cancer 2014; 61:1513–1517. © 2014 Wiley Periodicals, Inc.
Measurement of socio‐economic status in families of children with cancer in Guatemala
Authors: De Pernillo M. , Rivas S. , Fuentes L. , Antillon F. , Barr R.D.
Published: April 2014

The prospects for survival of children in low and middle income countries are linked to their families socio‐economic status (SES), of which income is only one component. Developing a comprehensive measure of SES is required. Informed by clinical experience, a 15‐item instrument was designed in Guatemala to categorize SES by five levels in each item. Almost 75% of families attending the Unidad Nacional de Oncología Pediátrica were in the lowest three of six categories, providing a framework for stratified financial and nutritional support. The measure of SES offers an opportunity for examining associations with health outcomes throughout Latin America. Pediatr Blood Cancer 2014;61:2071–2073. © 2014 Wiley Periodicals, Inc.
Preclinical evaluation of nanoparticle albumin‐bound paclitaxel for treatment of pediatric bone sarcoma
Authors: Wagner Lars M. , Yin Hong , Eaves David , Currier Mark , Cripe Timothy P.
Published: April 2014

The combination of docetaxel and gemcitabine is frequently used to treat recurrent bone sarcoma. Nanoparticle albumin‐bound paclitaxel (nab‐paclitaxel) is less toxic and more active than docetaxel or paclitaxel for breast cancer patients. The combination of nab‐paclitaxel and gemcitabine has preclinical synergy and is approved to treat pancreatic cancer. We observed growth inhibition and improved survival with nab‐paclitaxel in a Ewing sarcoma xenograft, and activity was additive with gemcitabine in an osteosarcoma model. Primary Ewing sarcoma tumors expressed the transport protein SPARC, previously associated with nab‐paclitaxel activity. These findings provide rationale for further evaluation of nab‐paclitaxel with gemcitabine for bone sarcoma. Pediatr Blood Cancer 2014;61:2096–2098. © 2014 Wiley Periodicals, Inc.
Effect of shape and size of nickel‐coated particles fillers on conductivity of silicone rubber‐based composites
Authors: Zhou H. , Xia Z.D. , Wang X.Y. , Li Z. , Li T.T. , Guo F.
Published: April 2014

Electrically conductive polymer composites have been widely used in recent years. The resistivity of the composites is influenced by several factors. The conductive silicone rubbers (CSRs) were prepared by adding the nickel‐coated graphite (Ni‐G) and/or nickel‐coated carbon fiber (Ni‐CF) into liquid silicon rubbers which were then subjected to the vulcanization. The effect of particle shape and size on the electrical conductivity of CSR was investigated; the results indicate that Ni‐CF filled CSR have lower percolation threshold than Ni‐G filled CSR. Compared to the filled particles with larger size, a higher amount of smaller particles are needed to form the same conductive pathway in CSR. Thus, there are more contact points in conductive pathway, which increase the total contact resistance. The volume resistivity of CSR can be significantly reduced by the doping of Ni‐CF particles, while the effect begins to wear off under high doping content. The fiber‐like Ni‐CF has a good “bridging” function for the formation of conductive pathway in CSR, which is greatly enhanced by increasing the length to diameter (l/d) ratio of Ni‐CF particles. Therefore, doping of the particles that have low percolation threshold can reduce the resistivity of the composites. POLYM. COMPOS., 36:1371–1377, 2015. © 2014 Society of Plastics Engineers
Development of natural fiber‐reinforced plastics (NFRP) based on biobased polyethylene and waste fibers from Posidonia oceanica seaweed
Authors: Ferrero B. , Fombuena V. , Fenollar O. , Boronat T. , Balart R.
Published: April 2014

In the present study the valorization of wastes from Posidonia oceanica (PO) has been carried out in order to obtain a fully biobased composite material in combination with a biobased polyethylene obtained from sugar cane as matrix. Morphological analysis by scanning electron microscopy (SEM) of the fractured surfaces from impact tests has revealed a homogenous distribution of particles of PO, as a consequence, good balanced properties have been obtained for composites with PO contents in the 5–40 wt%. Thermal properties of composites have been studied through differential scanning calorimetry (DSC) and thermogravymetric analysis (TGA); the obtained results show an improvement on the thermal degradation. With regard to thermomechanical properties, dynamic mechanical analysis (DMA) results have shown a much enhanced storage modulus (G′) as the Posidonia oceanica content increases. Tensile tests have shown a remarkable increase in stiffness with tensile modulus values about 60% higher for composites with 40 wt% with regard to unfilled material. In a similar way, the flexural modulus is more than twice with regard the unloaded polyethylene. Shore D hardness confirms this improvement on mechanical properties and Charpy impact test shows values very similar to sample without PO, so that the intrinsic high impact energy absorption of HDPE is maintained in HDPE‐PO composites. The water uptake test determines that the water absorption percent does not exceed 8%, which is relatively low for a high immersion time (5 months), which guarantees a dimensional stability in lifetime for these composites. POLYM. COMPOS., 36:1378–1385, 2015. © 2014 Society of Plastics Engineers
Mechanical properties and creep behavior of poly(trimethylene terephthalate)/mesoporous silica composites
Authors: Liu Haiyun , Yin Li , Wu Defeng , Yao Zhen , Zhang Ming , Chen Chong , Fu Pengfei , Qin Jing
Published: April 2014

The poly(trimethylene terephthalate) (PTT) containing mesoporous silica (SBA‐15) prepared by in situ polymerization were used as the master batch in this work and mixed with the commercial PTT to fabricate PTT/mesoporous silica composites. The mechanical properties and viscoelastic behaviors such as creep and creep recovery of as‐obtained composite system were then studied in detail. The results reveal an evident reinforcing effect of the mesoporous SBA‐15 particles at the lower loading levels. Compared with those of the pure PTT, the tensile strength and impact strength of the composite with 0.5 wt% SBA‐15 particles increase by about 26% and 10%, respectively. This is attributed to the physical crosslinking between SBA‐15 and PTT chain caused by the mesoporous structure of SBA‐15 particle, which is confirmed by the increased glass transition temperature of the composites relative to the pure PTT. At the higher loading levels, however, the presence of mesoporous particle reduces the overall strength of PTT because the concentration of lower molecular weight PTT in the master batch also increases with increasing loading of SBA‐15. Therefore, superfluous addition of master batch has negative contribution to the mechanical strength of PTT composites. Besides, the composite system presents the higher creep levels and the lower recovery rates than the pure PTT, indicating that the presence of mesoporous SBA‐15 particles restrains the movements of PTT chain segments during creep and creep recovery. This is further confirmed by the viscoelastic model predictions. POLYM. COMPOS., 36:1386–1393, 2015. © 2014 Society of Plastics Engineers
Biodegradability, mechanical, and thermal properties of thermoplastic starch/cuttlebone composites
Authors: Bootklad Munlika , Kaewtatip Kaewta
Published: April 2014

This work focused on improvements to the properties of thermoplastic starch (TPS) by using cuttlebone (CB) as the bio‐filler. The effect of CB on the properties of TPS was compared to that of commercial calcium carbonate (CC). The good adhesion achieved between the TPS matrix and the cuttlebone powder produced improvements in the tensile strength of their composites, whereas the tensile strength of TPS/CC composite was lower due to the presence of filler agglomerates. The biodegradation of the TPS and the composites were analyzed by the soil burial test. This showed that cuttlebone decreased the biodegradation rate. The thermal degradation temperatures of TPS, a TPS/CC composite and a TPS/CB composite showed very similar behavior. POLYM. COMPOS., 36:1401–1406, 2015. © 2014 Society of Plastics Engineers
Preparation of expandable graphite with silicate assistant intercalation and its effect on flame retardancy of ethylene vinyl acetate composite
Authors: Pang Xiu‐Yan , Tian Yu , Weng Meng‐Qi
Published: April 2014

A halogen‐free intumescent flame retardant expandable graphite composite (EG), with an initial expansion temperature of 202°C and expansion volume of 517 mL g−1, was successfully prepared via a facile two‐step intercalation method, i.e. using KMnO4 as oxidant and H2SO4, Na2SiO3·9H2O as intercalators. The prepared EG flame retardant was characterized by field emission scanning electron microscope, X‐ray diffraction spectroscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. Furthermore, flame retardancy and thermal property of various ethylene vinyl acetate copolymer (EVA) composites, including EVA/EG and EVA/EG/APP (ammonium polyphosphate) specimens, were studied through limiting oxygen index instrument (LOI), vertical combustion UL‐94 rating, thermal gravimetric and differential thermal analysis. The results indicate that the EVA/EG and EVA/EG/APP composites exhibit a better flame retardancy. Addition of EG at a mass fraction of 30% leads LOI of 70EVA/30EG composite improved to 28.7%. Even more, the synergistic effect between EG and APP improves the LOI of 70EVA/10APP /20EG composite to 30.7%. This synergistic efficiency is attributed to the formation of compact and stable layer‐structure, and the prepared EG can make EVA composite reach the UL‐94 level of V‐0. POLYM. COMPOS., 36:1407–1416, 2015. © 2014 Society of Plastics Engineers
Carbon nanotube/polymer nanocomposites: A study on mechanical integrity through nanoindentation
Authors: Koumoulos Elias P. , Jagdale Pravin , Kartsonakis Ioannis A. , Giorcelli Mauro , Tagliaferro Alberto , Charitidis Constantinos A.
Published: April 2014

Carbon nanotubes (CNTs) are under intense investigation in materials science owing to their potential for modifying the mechanical proprieties of their composites. In this work, nanomechanical and nanotribological properties of polymer composites, reinforced with multiwall carbon nanotubes (MWCNTs) and single wall carbon nanotubes (SWCNTs), have been studied using the nanoindentation and nanoscratch technique. In particular, three different epoxy resins reinforced using several percentage of two different types of MWCNTs have been studied (range 0–7 wt%). Another resin was reinforced using MWCNTs (range 0–2.5 wt%) and SWCNTs (range 0–5 wt%) as fillers. Hardness and elastic modulus using nanoindenter instrument have been evaluated, while the coefficient of friction of the nanocomposites is obtained using nanoscratch. The results show an evident dependence with the percentage of CNTs. For all types of resins, an optimum in nanomechanical properties is found at intermediate levels of CNTs filling. POLYM. COMPOS., 36:1432–1446, 2015. © 2014 Society of Plastics Engineers
Preparation and characterization of epoxy/carbon fiber composite capacitors
Authors: Li Sumin , Zhao Yutao , Zhang Zhao , Tang Hua
Published: April 2014

Capacitors based on structural carbon fiber electrodes and epoxy‐based gel polymer electrolyte have been fabricated. The electrochemical properties of electrolytes and capacitors were evaluated by linear sweep voltammetry, cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. Surface modification of carbon fibers was carried out by oxidation, and the structural and surface characteristics of carbon fibers were investigated by scanning electron microscope, Brunauer–Emmet–Teller, and Boehm titration. The results showed that the electrochemical stability window of the electrolyte reached 2.75 V and the ionic conductivity reached the order of 10−5 S/cm at room temperature. Surface modification of carbon fiber by oxidation can enlarge fiber area and strengthen fiber chemical activity, as well as its energy storage ability. The specific capacitance of epoxy/carbon fiber composite capacitor was obtained as high as 3.0 F/g with good cycling performance. POLYM. COMPOS., 36:1447–1453, 2015. © 2014 Society of Plastics Engineers
An investigation into the hydrogen bond of poly (p‐phenylene benzobisoxazole)/carboxylic carbon nanotube composites, insight from quantum mechanics/molecular mechanics simulation
Authors: Hu Kun , Zhuang Qixin , Liu Xiaoyun , Han Zhewen
Published: April 2014

Poly (p‐phenylene benzobisoxazole)/carbon nanotube (PBO/CNTs) composites have already been experimentally synthesized with the outstanding mechanical and electrical properties. Carboxylic carbon nanotubes (CNT‐COOH), obtained by acid treatment, can better disperse than pristine nanotubes in PBO matrix, which is estimated due to hydrogen bonds between them and investigated by Quantum Mechanics/Molecular mechanics (QM/MM) calculation. In the dynamic simulation, the N atoms in PBO and H atoms in carboxyl can be close enough to form hydrogen bond and the angle of oxygen–hydrogen–nitrogen (OHN) is obtuse, suitable for hydrogen bond. Further more, the electrostatic potential (ESP) and ESP fit charge of N and O atoms in PBO has been measured by Density Functional Theory (DFT) calculation to prove that hydrogen bonds can be formed only by N atoms in the heterocycle of PBO and H atoms in carboxyl of the CNT‐COOH. POLYM. COMPOS., 36:1454–1461, 2015. © 2014 Society of Plastics Engineers
Poly (o‐anisidine)‐MWCNT nanocomposite: Synthesis, characterization and anticorrosion properties
Authors: Yeole K. V. , Mahajan L. H. , Mhaske S. T.
Published: April 2014

Poly (o‐anisidine) (POA) ‐ Multi‐walled carbon nanotube (MWCNT) nanocomposites were synthesized by simple in‐situ chemical oxidative technique. Synthesized nanocomposites were characterized for their structure, morphology, thermal and electrical properties. Spectral studies indicated the presence of interactions between poly (o‐anisidine) and the surface of MWCNTs. Conductivity of 2.82 × 10−2 S cm−1 was obtained for POA‐MWCNT nanocomposite sample containing 21.2% wt. of POA. POA‐MWCNT nanocomposites thus synthesized were incorporated into epoxy based coating formulation and its anticorrosion property was studied. The coatings were also characterized by physicochemical as well as physicomechanical studies. The aim of this study was to develop a facile method for the eco‐friendly synthesis of fillers having better dispersing properties for coating having superior corrosion protective properties. POLYM. COMPOS., 36:1477–1485, 2015. © 2014 Society of Plastics Engineers