bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of LDPC‐coded optical on‐off keying communication systems
Authors: Tseng Shu‐Ming , Hsieh Chih‐Hung , Wang Yung‐Chung , Tsai Fu‐Hsiang , Lin Kuen‐Cherng 
Published: February 2007

AbstractIn this letter, we study the performance of low‐density parity‐check (LDPC) codes in a Poisson optical channel with on–off keying modulation. We modify the iterative decoding algorithm used in binary phase‐shift keying modulation and additive white Gaussian noise channels. The simulation results show that the LDPC codes has performance improvements over parallel concatenated convolutional codes. Therefore, LDPC codes is well suited for optical channels with signal energy constraints. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 976–979, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22320
Internal shorted monopole antenna for the watch‐type wireless communication device for Bluetooth operation
Authors: Wu Chih‐Hsien , Wong Kin‐Lu , Lin Yuan‐Chih , Su Saou‐Wen 
Published: February 2007

AbstractAn internal shorted monopole antenna suitable to be embedded within the watch‐type wireless communication device is presented. The antenna generally has a planar configuration and is mounted conformal along the side surfaces of the wireless device to operate as an internal or concealed antenna. The antenna also shows a low profile of 4 mm only, yet providing a wide bandwidth for Bluetooth operation in the 2.4 GHz band (2400–2484 MHz). In addition, the antenna is designed to be short‐circuited to an upper ground plane mounted above the main system ground plane of the wireless device. With the proposed arrangement, reduced coupling between the antenna and the nearby lossy medium can be achieved. Hence, when the wireless device with the proposed antenna is worn around the user's wrist or forearm, which functions as a lossy medium, the antenna's radiation efficiency can still reach about 50% over the operating band. Details of the proposed antenna and the promising watch‐type wireless communication device are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 942–946, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22322
Genes, language development, and language disorders
Authors: Smith Shelley D. 
Published: February 2007

AbstractGenetic factors are important contributors to language and learning disorders, and discovery of the underlying genes can help delineate the basic neurological pathways that are involved. This information, in turn, can help define disorders and their perceptual and processing deficits. Initial molecular genetic studies of dyslexia, for example, appear to converge on defects in neuronal and axonal migration. Further study of individuals with abnormalities of these genes may lead to the recognition of characteristic cognitive deficits attributable to the neurological dysfunction. Such abnormalities may affect other disorders as well, and studies of co‐morbidity of dyslexia with attention deficit disorder and speech sound disorder are helping to define the scope of these genes and show the etiological and cognitive commonalities between these conditions. The genetic contributions to specific language impairment (SLI) are not as well defined at this time, but similar molecular approaches are being applied to identify genes that influence SLI and comorbid disorders. While there is co‐morbidity of SLI with dyslexia, it appears that most of the common genetic effects may be with the language characteristics of autism spectrum disorders rather than with dyslexia and related disorders. Identification of these genes and their neurological and cognitive effects should lay out a functional network of interacting genes and pathways that subserve language development. Understanding these processes can form the basis for refined procedures for diagnosis and treatment. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:96–105.
Word‐attack skills in individuals with mental retardation
Authors: Saunders Kathryn J. 
Published: February 2007

AbstractThis article assesses the state of the literature on word‐attack skills and phonological awareness (PA) in individuals with mental retardation, in light of progress towards the development of effective teaching procedures. The literature contains promising findings. Studies have shown PA to be correlated with word‐attack skills in individuals with mental retardation, as has been shown conclusively in typically developing children. This suggests that instruction in PA would facilitate the acquisition of word‐attack skills in individuals with mental retardation, as it does with typically developing children. As of yet, however, very few experimental studies designed to demonstrate effective teaching procedures for PA and word‐attack skills have been published. This research field might evolve most effectively and efficiently by following a two‐step research program. First, test new teaching procedures in a series of small‐N studies, each study incorporating modifications of teaching procedures based on the results of the previous study. Once procedures prove effective at this level, the resources necessary to pursue large‐scale studies can be used to their best advantage. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:78–84.
Differential treatment intensity research: A missing link to creating optimally effective communication interventions
Authors: Warren Steven F. , Fey Marc E. , Yoder Paul J. 
Published: February 2007

AbstractResearch over the past 50 years has yielded several promising approaches and many specific intervention techniques designed to enhance the communication and language development of young children with intellectual and developmental delays and disabilities. Yet virtually no systematic research has been conducted on the effects of different treatment intensities. We review how intervention intensity has been defined in the literature and propose a set of terms borrowed from medicine that are intended to capture the dynamic aspects of this concept as an aid to further investigation. On the basis of this approach, we propose four types of knowledge that can be generated through the systematic study of treatment intensity and discuss appropriate methods for investigating the effects of differential treatment intensities. We conclude with three recommendations for the field. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:70–77.
Language development and fragile X syndrome: Profiles, syndrome‐specificity, and within‐syndrome differences
Authors: Abbeduto Leonard , Brady Nancy , Kover Sara T. 
Published: February 2007

AbstractFragile X syndrome (FXS) is the leading inherited cause of mental retardation. In this article, we review what is known about the language and related problems of individuals with FXS. In doing so, we focus on the syndrome‐specific features of the language phenotype and on the organismic (i.e., genetic and individual neurocognitive and behavioral) and environmental factors associated with within‐syndrome variation in the phenotype. We also briefly review those aspects of the behavioral phenotype of FXS that are relevant for understanding syndrome‐specific features of, and within‐syndrome variability in, language. The review includes summaries of research on the prelinguistic foundations for language development and on each of the major components of language (i.e., vocabulary, morphosyntax, and pragmatics). Throughout the review, we point out implications of existing research for intervention as well as directions for future research. © 2007 Wiley‐Liss, Inc. MRDD Research Reviews 2007;13:36–46.
Partial k‐space reconstruction in single‐shot diffusion‐weighted echo‐planar imaging
Authors: Storey Pippa , Frigo Fred J. , Hinks R. Scott , Mock Bryan J. , Collick Bruce D. , Baker Nicole , Marmurek Jonathan , Graham Simon J. 
Published: February 2007

AbstractPartial k‐space sampling is frequently used in single‐shot diffusion‐weighted echo‐planar imaging (DW‐EPI) to reduce the TE and thereby improve the SNR. However, it increases the sensitivity of the technique to bulk rotational motion, which introduces a phase gradient across the tissue that shifts the echo in k‐space. If the echo is displaced into the high spatial frequencies, conventional homodyne reconstruction fails, causing intensity oscillations across the image. Zero‐padding, on the other hand, compromises the image resolution and may cause truncation artifacts. We present an adaptive version of the homodyne algorithm that detects the location of the echo in k‐space and adjusts the center and width of the homodyne filters accordingly. The adaptive algorithm produces artifact‐free images when the echo is shifted into the high positive k‐space range, and reduces to the standard homodyne algorithm in the absence of bulk motion. Magn Reson Med 57:614–619, 2007. © 2007 Wiley‐Liss, Inc.
Quantitative comparison of 2D and 3D circumferential strain using MRI tagging in normal and LBBB hearts
Authors: Tecelão Sandra R.R. , Zwanenburg Jaco J.M. , Kuijer Joost P.A. , de Cock Carel C. , Germans Tjeerd , van Rossum Albert C. , Marcus J. Tim 
Published: February 2007

AbstractThe response to cardiac resynchronization therapy (CRT), which is applied to patients with heart failure (HF) and left bundle‐branch block (LBBB), can be predicted from the mechanical dyssynchrony measured on circumferential strain. Circumferential strain can be assessed by either 2D or 3D strain analysis. In this study was evaluated the difference between 2D and 3D circumferential strain using MR tagging with high temporal resolution (14 ms). Six healthy volunteers and five patients with LBBB were evaluated. We compared the 2D and 3D circumferential strains by computing the mechanical dyssynchrony and the cross correlation (r) between 2D and 3D strain curves, and by quantifying the differences in peak circumferential shortening, time to onset, and time to peak of shortening. The obtained maximum r2 values were 0.97 ± 0.03 and 0.87 ± 0.16 for the healthy and LBBB populations, respectively, and thus showed a good similarity between 2D and 3D strain curves. No significant difference was observed between 2D and 3D in time to onset, time to peak, or peak circumferential shortening. Thus, to measure dyssynchrony, 2D strain analysis will suffice. Since 2D analysis is easier to implement than 3D analysis, this finding brings the application of MRI tagging and strain analysis closer to the clinical routine. Magn Reson Med 57:485–493, 2007. © 2007 Wiley‐Liss, Inc.
Whole‐heart cine MRI using real‐time respiratory self‐gating
Authors: Uribe Sergio , Muthurangu Vivek , Boubertakh Redha , Schaeffter Tobias , Razavi Reza , Hill Derek L.G. , Hansen Michael S. 
Published: February 2007

AbstractTwo‐dimensional (2D) breath‐hold cine MRI is used to assess cardiac anatomy and function. However, this technique requires cooperation from the patient, and in some cases the scan planning is complicated. Isotropic nonangulated three‐dimensional (3D) cardiac MR can overcome some of these problems because it requires minimal planning and can be reformatted in any plane. However, current methods, even those that use undersampling techniques, involve breath‐holding for periods that are too long for many patients. Free‐breathing respiratory gating sequences represent a possible solution for realizing 3D cine imaging. A real‐time respiratory self‐gating technique for whole‐heart cine MRI is presented. The technique enables assessment of cardiac anatomy and function with minimum planning or patient cooperation. Nonangulated isotropic 3D data were acquired from five healthy volunteers and then reformatted into 2D clinical views. The respiratory self‐gating technique is shown to improve image quality in free‐breathing scanning. In addition, ventricular volumetric data obtained using the 3D approach were comparable to those acquired with the conventional multislice 2D approach. Magn Reson Med 57:606–613, 2007. © 2007 Wiley‐Liss, Inc.
Improved reproducibility of right ventricular volumes and function estimation from cardiac magnetic resonance images using level‐set models
Authors: Catalano Oronzo , Corsi Cristiana , Antonaci Serena , Moro Guido , Mussida Maria , Frascaroli Mauro , Baldi Maurizia , Caiani Enrico , Lamberti Claudio , Cobelli Franco 
Published: February 2007

AbstractThis study aims to assess whether an alternative method, that is based on volumetric surface detection (VoSD) without tracing and is totally free of geometric assumptions, can improve the reproducibility of right ventricular (RV) volume quantification from cardiac magnetic resonance (CMR) images, in comparison with a conventional disk‐area technique. In a sample of 23 patients, with wide variability of RV end‐diastolic volume (EDV: 47–131 ml), end‐systolic volume (ESV: 20–76 ml), and ejection fraction (EF: 29–73%), using the standard method (Argus, Siemens) as the reference, the VoSD method showed good agreement for EDV, ESV, and EF estimations (correlation coefficient: 0.91, 0.94, and 0.94; Bland‐Altman biases: 1 ml, 1 ml, and 0%; limits of agreement: ±16 ml, ±11 ml, and ±11%, respectively). An analysis of the reproducibility of the two methods showed lower intraobserver variability for the VoSD method than for the conventional method, as evidenced by the coefficient of variability (CoV) values (2–6% vs. 8–15%; P < 0.05). In addition, the VoSD method showed improved interobserver reproducibility (7–10% vs. 8–15%), but the difference was statistically significant only for EF estimation variability (8 vs. 15%, P < 0.05). In conclusion, the newly developed VoSD technique allows accurate measurements of RV volumes and function, and appears to be more reproducible than the conventional methodology. Magn Reson Med 57:600–605, 2007. © 2007 Wiley‐Liss, Inc.
Multispectral quantification of tissue types in a RIF‐1 tumor model with histological validation. Part I
Authors: Henning Erica C. , Azuma Chieko , Sotak Christopher H. , Helmer Karl G. 
Published: February 2007

AbstractAccurate assessments of therapeutic efficacy are confounded by intra‐ and intertumor heterogeneity. To address this issue we employed multispectral (MS) analysis using the apparent diffusion coefficient (ADC), T2, proton density (M0), and k‐means (KM) clustering algorithm to identify multiple compartments within both viable and necrotic tissue in a radiation‐induced fibrosarcoma (RIF‐1) tumor model receiving single‐dose (1000 cGy) radiotherapy. Optimization of the KM method was achieved through histological validation by hematoxylin‐eosin (H&E) staining and hypoxia‐inducible factor‐1α (HIF‐1α) immunohistochemistry. The optimum KM method was determined to be a two‐feature (ADC, T2) and four‐cluster (two clusters each of viable tissue and necrosis) segmentation. KM volume estimates for both viable (r = 0.94, P < 0.01) and necrotic (r = 0.69, P = 0.07) tissue were highly correlated with their H&E counterparts. HIF‐1α immunohistochemistry showed that the intensity of HIF‐1α expression tended to be concentrated in perinecrotic regions, supporting the subdivision of the viable tissue into well‐oxygenated and hypoxic regions. Since both necrosis and hypoxia have been implicated in poor treatment response and reduced patient survival, the ability to quantify the degree of necrosis and the severity of hypoxia with this method may aid in the planning and modification of treatment regimens. Magn Reson Med 57:501–512, 2007. © 2007 Wiley‐Liss, Inc.
Spinal cord atrophy in injured rodents: High‐resolution MRI
Authors: Deng Xiang , Ramu Jaivijay , Narayana Ponnada A. 
Published: February 2007

AbstractLongitudinal magnetic resonance imaging (MRI) was performed in normal and spinal cord (SC)‐injured rodents. A fast technique based on polar B‐spline snake was developed to extract the SC contour from the MR images in order to estimate the cord atrophy. Based on pooled data from all of the imaging studies, the extracted contours correlated well with manually defined contours. Results from the injured group showed cord atrophy shortly after the contusion injury. The maximum amount of atrophy (9.7% ± 3.5% decrease in the cross‐sectional area (CSA)) occurred mainly at the epicenter around 14 days postinjury. The caudal and rostral segments in the injured group did not exhibit significant atrophy compared to the normal controls. The MRI‐based atrophy measurements obtained in injured cords are consistent with previous histological findings. Magn Reson Med 57:620–624, 2007. © 2007 Wiley‐Liss, Inc.
Reduced field‐of‐view MRI using outer volume suppression for spinal cord diffusion imaging
Authors: Wilm B.J. , Svensson J. , Henning A. , Pruessmann K.P. , Boesiger P. , Kollias S.S. 
Published: February 2007

AbstractA spin‐echo single‐shot echo‐planar imaging (SS‐EPI) technique with a reduced field of view (FOV) in the phase‐encoding direction is presented that simultaneously reduces susceptibility effects and motion artifacts in diffusion‐weighted (DW) imaging (DWI) of the spinal cord at a high field strength (3T). To minimize aliasing, an outer volume suppression (OVS) sequence was implemented. Effective fat suppression was achieved with the use of a slice‐selection gradient‐reversal technique. The OVS was optimized by numerical simulations with respect to T1 relaxation times and B1 variations. The optimized sequence was evaluated in vitro and in vivo. In simulations the optimized OVS showed suppression to <0.25% and ∼3% in an optimal and worst‐case scenario, respectively. In vitro measurements showed a mean residual signal of <0.95% ± 0.42 for all suppressed areas. In vivo acquisition with 0.9 × 1.05 mm2 in‐plane resolution resulted in artifact‐free images. The short imaging time of this technique makes it promising for clinical studies. Magn Reson Med 57:625–630, 2007. © 2007 Wiley‐Liss, Inc.
Gadolinium‐enhanced off‐resonance contrast angiography
Authors: Edelman Robert R. , Storey Pippa , Dunkle Eugene , Li Wei , Carrillo Andres , Vu Anthony , Carroll Timothy J. 
Published: February 2007

AbstractWe describe a novel physical basis and methodology for gadolinium (Gd)‐enhanced MRA, which we call “off‐resonance contrast angiography” (ORCA). Unlike standard contrast‐enhanced (CE) MR angiography (MRA), ORCA contrast depends not on T1 but on Gd‐induced shifts in intravascular resonance frequency due to the bulk magnetic susceptibility (BMS) effects of Gd. The method was tested at 3 Tesla in phantoms with a range of dilutions of Gd‐DTPA and ultrasmall iron oxide contrast agent (CA). With the use of ORCA, complete background suppression was obtained without image subtraction. As a result, catheters filled with various Gd dilutions proved to be highly conspicuous in ORCA projection images. This feature may make ORCA particularly attractive for passive catheter tracking during MR‐guided endovascular procedures. Gd‐induced intravascular frequency shifts were measured in human subjects and found to be in the expected range. ORCA was used to create angiograms of forearm veins that were comparable in quality to standard CE‐MRA. In addition, ORCA images of the extracranial carotid bifurcation were successfully acquired during intravenous contrast administration. However, significant technical restrictions also exist, including a dependence on vessel orientation with respect to B0, and sensitivity to static field inhomogeneities. Further study is needed to determine the practicality and potential clinical utility of this method. Magn Reson Med 57:475–484, 2007. © 2007 Wiley‐Liss, Inc.
Expression pattern of myostatin in gastrocnemius muscle of rats after sciatic nerve crush injury
Authors: Liu Mei , Zhang Donglei , Shao Chenxin , Liu Jie , Ding Fei , Gu Xiaosong 
Published: February 2007

AbstractMyostatin is a strong inhibitor of skeletal muscle growth. The purpose of this study was to investigate myostatin expression profiles during denervation‐induced muscle atrophy in order to understand the relationship between myostatin expression and muscle atrophy. We constructed a sciatic nerve crush model, undertook morphometric analyses of rat gastrocnemius muscle to evaluate the degree of muscle atrophy, and utilized a real‐time quantitative reverse transcription–polymerase chain reaction (RT‐PCR) and Western blot analysis to measure myostatin mRNA and protein expression levels, respectively, in the gastrocnemius at different time‐points after nerve injury. Muscle atrophy changed in a parabola‐like manner from day 1 to day 28 after nerve injury, with a maximum value at day 14. During this time, myostatin expression changed in the reverse manner, with myostatin mRNA or protein expression gradually increasing from days 1–14, and then gradually declining to day 28, when the normal level was reached. Statistical analyses further provided evidence for a significant negative linear correlation between myostatin expression and muscle atrophy within a 28‐day period after nerve injury. Our study thus describes the expression pattern of myostatin in response to a specific type of muscle atrophy and raises the possibility of developing myostatin as a therapeutic target for future clinical applications. Muscle Nerve, 2007
Normative values and the effects of age, gender, and handedness on the Moberg Pick‐Up Test
Authors: Amirjani Nasim , Ashworth Nigel L. , Gordon Tessa , Edwards David C. , Chan K. Ming 
Published: February 2007

AbstractThe Moberg Pick‐Up Test is a standardized test for assessing hand dexterity. Although reduction of sensation in the hand occurs with aging, the effect of age on a subject's performance of the Moberg Pick‐Up Test has not been examined. The primary goal of this study was to examine the impact of aging and, secondarily, the impact of gender and handedness, on performance of the Moberg Pick‐Up Test in 116 healthy subjects. The average time to complete each of the four subsets of the test was analyzed using the Kruskal–Wallis, Mann–Whitney U, and Wilcoxon signed‐rank tests. The results show that hand dexterity of the subjects was significantly affected by age, with young subjects being the fastest and elderly subjects the slowest. Women accomplished the test faster than men, and task performance with the dominant hand was faster than with the non‐dominant hand. Use of normative values established based on age and gender is a valuable objective tool to gauge hand function in patients with different neurologic disorders. Muscle Nerve, 2007
Myasthenia gravis presenting with unusual neurogenic muscle atrophy
Authors: Samuraki Miharu , Furui Eisuke , Komai Kiyonobu , Takamori Masaharu , Yamada Masahito 
Published: February 2007

AbstractWe report a patient with myasthenia gravis who had neurogenic muscle atrophy in association with external ophthalmoplegia and weakness of the upper limbs. Neurogenic changes in the limb muscles were found on needle electromyography and histological studies. Symptoms improved and atrophy of the limbs diminished after intravenous immunoglobulin and oral corticosteroid therapy. We concluded that functional interruption of the neuromuscular junction caused the neurogenic muscle atrophy and that this was relieved by appropriate therapy. Muscle Nerve, 2007