bluuebunny/crossref_metadata_2025_split huggingface dataset:
Community organizational learning: Case studies illustrating a three‐dimensional model of levels and orders of change
Authors: Perkins Douglas D. , Bess Kimberly D. , Cooper Daniel G. , Jones Diana L. , Armstead Theresa , Speer Paul W. 
Published: March 2007

AbstractWe present a three‐dimensional cube framework to help community organizational researchers and administrators think about an organization's learning and empowerment‐related structures and processes in terms of firstorder (incremental or ameliorative) and second‐order (transformative) change at the individual, organizational, and community levels. To illustrate application of the framework, case studies of three different types of exemplary nonprofit organizations (a participatory neighborhood planning organization, a grassroots faith‐based social action coalition, and a larger community‐based human service agency) were based on qualitative interviews and participant observations. Our analysis, rooted in organizational learning theory, suggests that organizations that empower staff and volunteers through opportunities for learning and participation at theindividual levelare better able to succeed in terms oforganizational‐levellearning and transformation.Community‐levelchange is particularly difficult but must be made a more explicit goal. Learning that can lead to second‐order change at each level must help participants engage in critical analysis of (a) the organization's demonstrated goals and values; (b) the power relationships implicit in decision making at each level; (c) the interdependent role of participant stakeholders and organizations as part of a complex, community‐wide (or larger) system; and (d) how to work toward transformative change of all of the above. © 2007 Wiley Periodicals, Inc.
Community readiness as a multidimensional construct
Authors: Chilenski Sarah M. , Greenberg Mark T. , Feinberg Mark E. 
Published: March 2007

AbstractBoth the organizational studies literature and the community psychology literature discuss the importance of readiness when implementing change. Although each area emphasizes different characteristics, several common themes are present within the literature. The current study integrates and applies organizational and community psychology literature in evaluating community readiness in the context of a school–community–university collaborative prevention model. Results demonstrate (a) that there is substantial agreement between members of community prevention teams on the level of readiness of a community; (b) that readiness is a cohesive, but multidimensional, construct related to hypothesized community and individual characteristics; and (c) that there is small to moderate agreement between members of prevention teams and their “agency directors.” These results support the notion that clear “theories of change” need to be formulated before deciding how to assess community readiness, as assessments will vary due to several factors: the type of respondent, the level in which analyses are conducted, and the specific community domain (i.e., school, workplace collaboration, collaboration experience) investigated. © 2007 Wiley Periodicals, Inc.
How settings change people: Applying behavior setting theory to consumer‐run organizations
Authors: Brown Louis D. , Shepherd Matthew D. , Wituk Scott A. , Meissen Greg 
Published: March 2007

AbstractSelf‐help initiatives stand as a classic context for organizational studies in community psychology. Behavior setting theory stands as a classic conception of organizations and the environment. This study explores both, applying behavior setting theory to consumer‐run organizations (CROs). Analysis of multiple data sets from all CROs in Kansas provide insight into how organizational size influences member participation, how members benefit from participation, and how behavior setting theory may need to be revised. Results suggest that members do benefit from participation. However, individual involvement in organizational planning and decision making does not appear to be the primary factor leading to member benefit. The predictions of behavior setting theory are found to be true, but results suggest that these predictions provide an incomplete picture of CROs. The incorporation of roles as a unit of analysis within behavior settings is suggested to improve the explanatory power of this theory. © 2007 Wiley Periodicals, Inc.
Evidence for positive and negative regulation of the mouse Cdx2 gene
Authors: Wang Wayne C.H. , Shashikant Cooduvalli S. 
Published: March 2007

AbstractThe caudal family of transcription factors specifies posterior structures during mouse development. We describe the cis‐regulatory regions that control mouse Cdx2 expression in the posterior neural tube and mesoderm. An 11.4 kb genomic fragment directs reporter gene expression in a pattern reflecting endogenous Cdx2 expression. A crucial enhancer is located in a 1 kb fragment upstream of the Cdx2 transcriptional start site. This enhancer by itself directs reporter gene expression to more anterior levels in the neural tube compared to the endogenous Cdx2 expression, suggesting the presence of negative regulatory elements outside the 1 kb fragment. A second enhancer, located in the first intron directs robust expression to the posterior two‐thirds of the developing embryo in a pattern that is ectopic to Cdx2 expression. The intronic enhancer activity is silenced in the context of the larger 11.4 kb reporter construct. Intron 1 contains two independent enhancers that specifically direct expression to mesoderm (MSE) and neural tube (NSE). Phylogenetic comparison of vertebrate Cdx2 sequences indicates several conserved regions of sequences within the three‐enhancer regions. A transcription factor database search suggests potential binding sites for factors involved in FGF and Wnt signaling pathways. J. Exp. Zool. (Mol. Dev. Evol.) 308B:308–321, 2007. © 2007 Wiley‐Liss, Inc.
Early developmental plasticity and integrative responses in arctic charr (Salvelinus alpinus): effects of water velocity on body size and shape
Authors: Grünbaum Thomas , Cloutier Richard , Mabee Paula M. , Le François Nathalie R. 
Published: March 2007

AbstractEnvironmental conditions such as temperature and water velocity may induce changes among alternative developmental pathways, i.e. phenotypic responses, in vertebrates. However, the extent to which the environment induces developmental plasticity and integrated developmental responses during early ontogeny of fishes remains poorly documented. We analyzed the responses of newly hatched Arctic charr (Salvelinus alpinus) to four experimental water velocities during 100 days of development. To our knowledge, this work is the first to analyze developmental plasticity responses of body morphology to an experimental gradient of water velocities during early ontogeny of fish. Arctic charr body size and shape responses show first, that morphometric traits display significant differences between low and high water velocities, thus revealing directional changes in body traits. Secondly, trait variation allows the recognition of critical ontogenetic periods that are most responsive to environmental constraints (40–70 and 80–90 days) and exhibit different levels of developmental plasticity. This is supported by the observation of asynchronous timing of variation peaks among treatments. Third, morphological interaction of traits is developmentally plastic and time‐dependent. We suggest that developmental responses of traits plasticity and interaction at critical ontogenetic periods are congruent with specific environmental conditions to maintain the functional integrity of the organism. J. Exp. Zool. (Mol. Dev. Evol.) 308B:396–408, 2007. © 2007 Wiley‐Liss, Inc.
The future technical development of MRI
Authors: Riederer Stephen J. 
Published: March 2007

AbstractIn this essay the author makes predictions on how the future of MRI will develop for the short term, the intermediate term, and the long term; these periods of time are defined as the present to the next 3 years, 3 to 5 years, and beyond 5 years, respectively. For each time period, general scientific trends and specific applications are presented. Despite about 15 years of extensive scientific research and significant application to clinical imaging, there continue to be many opportunities for additional technical development in MRI as its role in clinical use and the extent of its scientific significance expand.
Respiratory and postprandial changes in portal flow rate: Assessment by phase contrast MR imaging
Authors: Sadek Ahmed G. , Mohamed Feroze B. , Outwater Eric K. , El‐Essawy Saleh S. , Mitchell Donald G. 
Published: March 2007

AbstractThe objective of this study was to investigate the variability of several different phase contrast (PC) magnetic resonance techniques and duplex Doppler imaging (DDI) for measuring portal flow rate (PFR) with different patterns of respiration before and after a standard meal. PFR was measured in nine normal volunteers in both fasting and postprandial states, using both 2D and cine PC MR techniques. Two‐dimensional PC technique was performed with and without breathhold (BH). Four different patterns of BH (relaxed maximal inspiration, expiration, Valsalva maneuver, and Müller or reversed Valsalva) were used. Cine PC technique was performed without BH. DDI measurement of PFR was done in the fasting state with relaxed inspiration. PFR measurements made by means of PC MR techniques varied, depending on BH method, and were systematically less than those obtained by DDI. PFR measured during inspiration was significantly less than that measured during expiration and other respiratory maneuvers (P < .03). PFR increased significantly after a meal for PC and Doppler measurements, with a range of mean increases of 24 to 74%. Two‐dimensional PC MR imaging techniques yielded differing measurements of PFR, depending on whether they were done with or without BH, as well as on the pattern of BH. PC mean measures of PFR were consistently less than those of DDI. The physiologic inspiratory decreases and postprandial increases of the PFR were evident from 2D and cine PC MRI techniques, as well as with DDI.
Abdominal phase‐contrast MR angiography: Breath‐Hold versus non‐breath‐hold techniques
Authors: Hara Amy K. , Burkart David J. , Johnson C. Daniel , Ehman Richard L. , Ilstrup Duane M. 
Published: March 2007

AbstractBreath‐hold magnetic resonance (MR) imaging is now replacing many non‐breath‐hold pulse sequences in the upper abdomen because of faster imaging times and improved image quality. The authors compared non‐breath‐hold cine phase‐contrast (PC) and breath hold 2D phase‐contrast (2DPC) magnetic resonance (MR) angiograms of the main portal vein (MPV) and superior mesenteric artery (SMA) in 12 volunteers. All angiograms were graded in overall image quality, vessel conspicuity, and signal‐to‐noise ratios (SNR). In the MPV MR angiograms, the breath‐hold 2DPC sequence produced better images than the non‐breath‐hold cine PC sequence as graded by overall image quality (P=.016) and SNR (P=.004). Conversely, in the SMA MR angiograms, the non‐breath‐hold cine PC sequence produced better images than the breath‐hold sequence in terms of overall image quality (P=.008) and SNR (P=.008). By reducing the most significant cause of image artifacts, (ie, using a breath‐hold 2DPC sequence to decrease respiratory misregistration of the MPV, and using a cardiac‐gated cine PC sequence to minimize pulsatile artifacts of the SMA), one can clearly optimize the quality of MR angiography.
Effects of through‐plane myocardial motion on phase‐difference and complex‐difference measurements of absolute coronary artery flow
Authors: Polzin Jason A. , Korosec Frank R. , Wedding Kristin L. , Grist Thomas M. , Frayne Richard , Peters Dana C. , Mistretta Charles A. 
Published: March 2007

AbstractWe have previously reported on a complex‐difference (CD) flow measurement technique that produces more accurate results than the phase‐difference (PD) flow measurement technique due to the greater immunity of the former method to partial volume effects. We report here on some of the ways in which through‐plane myocardial motion affects the accuracy of absolute coronary artery flow measurements obtained using the PD and CD techniques. We also discuss motion correction schemes that can be applied to the PD and CD processing methods to improve their accuracy. Computer simulations have been performed to assess the magnitude of the errors associated with these flow measurement techniques when they are applied to small vessels that are attached to a moving background. Laminar and plug flow, with and without complete background suppression, have been considered. Experiments with a moving vessel phantom have been conducted to test the performance of the PD and CD flow measurement techniques in circumstances similar to those simulated. The simulations and the experiments showed that, after corrections for throughplane motion are made, the CD method generally yields more accurate flow results than the PD method. As shown by the simulations, however, both methods yield compromised results due to subtle saturation effects that occur when the direction of myocardial motion is opposite the direction of blood flow. Unvalidated PD and CD measurements of coronary artery flow waveforms in human volunteers are presented to illustrate the magnitude of the proposed throughplane motion effects in vivo.
Dynamic MR imaging of recurrent postoperative cervical cancer
Authors: Yamashita Yasuyuki , Harada Mikihiko , Torashima Miyuki , Takahashi Mutsumasa , Miyazaki Kohji , Tanaka Nobuyuki , Okamura Hitoshi 
Published: March 2007

AbstractThe value of dynamic‐contrast enhanced MR imaging using FLASH technique was studied in 13 patients with postoperative recurrent cervical cancer verified histopathology and in 9 patients without recurrence. Dynamic FLASH imaging and conventional spin‐echo T1‐ and T2‐weighted sequences were compared in a prospective fashion with regard to accuracy of the diagnosis of recurrent tumor using biopsy results as the gold standard. The contrast between the recurrent tumor and the surrounding pelvic tissues was also analyzed. The accuracy of depicting recurrent tumor on dynamic images (82%) was superior to that of pre‐ and postcontrast T1‐weighted images and T2‐weighted images (64%, 68%, and 64%, respectively). The contrast between the recurrent tumor and pelvic fat was greater on precontrast T1‐weighted and dynamic images than on T2‐weighted and postcontrast T1‐weighted images. The dynamic images clearly showed involvement of the surrounding pelvic organs, because enhancement was observed exclusively in the tumor in the early dynamic phase. Accuracy regarding involvement of the urinary bladder or rectal wall on pre‐ and postcontrast T1‐weighted images and T2‐weighted images was lower than that on the dynamic images. Dynamic MR imaging has potential for use in the detection and evaluation of the extent of recurrent postoperative cervical cancer.
High‐resolution magnetic resonance imaging of normal porcine cartilaginous epiphyseal maturation
Authors: Babyn Paul S. , Kim Harry K. W. , Lemaire Claude , Gahunia Harpal K. , Cross Albert , Denanassy Joseph , Pritzker Kenneth P. H. 
Published: March 2007

AbstractThe aim of this study was to determine whether highresolution magnetic resonance (MR) imaging could differentiate epiphyseal and articular cartilage in the cartilaginous epiphysis and demonstrate its developmental changes. T1‐ and T2‐weighted (T1W and T2W) spin‐echo sequences at 50‐mm field of view (FOV) of hip joints were obtained from 14 piglets (newborn to 6 months). Subsequently, high‐resolution MR images (15‐mm FOV) of a biopsy core of the proximal femoral cartilaginous epiphysis were correlated with histology. Newborn cartilaginous epiphysis demonstrated homogeneous signal intensity on T1W and T2W imaging with abundant cartilage canals. From 2 weeks of age, the cartilaginous epiphysis showed a diminution of cartilage canals, with three zones evident on T2W imaging consisting of a low‐signal middle zone separating two higher signal zones. Histologic evaluation demonstrated four distinct morphologic laminas with a decrease in overall cartilage thickness with age. The laminas were not as well defined in the newborn compared with the older piglets. No simple correlation was found between the MR zonal pattern and the morphological laminas on histology. No distinct demarcation between the articular cartilage and epiphyseal cartilage was present. MR can visualize cartilage canals and demonstrate changes in the cartilaginous epiphysis that occur with maturation. What component of the cartilaginous epiphysis that accounts for the MR differences seen between newborn and older piglets remains unclear.
Incidental magnetization transfer contrast in fast spin‐echo imaging of cartilage
Authors: Yao Lawrence , Gentili Amilcare , Thomas Albert 
Published: March 2007

AbstractIn this article, the authors illustrate the contributions of incidental magnetization transfer contrast (MTC) to the signal characteristics of patellar cartilage on routine, multiplanar fast spin‐echo (FSE) images. Incidental MTC diminishes the signal of patellar cartilage by 30% on routine FSE scans. Spectral fat saturation does not significantly increase incidental MTC on multislice FSE acquisitions. By increasing the contrast between synovial fluid and patellar cartilage, incidental MTC may account for greater conspicuousness of chondromalacia on FSE as compared to conventional spin‐echo images. Incidental MTC may also alter or obscure the normal, laminar appearance of hyaline cartilage on short‐TE, FSE images.
MR imaging of tuberculous arthritis: Clinical and experimental studies
Authors: Suh Jin‐Suck , Lee Jong Doo , Cho Jae‐Hyun , Kim Myung Joon , Han Dae Yong , Cho Nam Hoon 
Published: March 2007

AbstractSignal‐intensity characteristics of magnetic resonance (MR) images were assessed in five patients and in 10 rabbits with tuberculous arthritis. MR imaging findings were compared with histologic findings in the animal study. In both of clinical and experimental cases, tuberculous lesions showed both intermediate and high signal intensity on T2‐weighted images, while they showed heterogeneously intermediate signal intensity on T1‐weighted images. As T2‐weighted images were compared with pathologic specimens, intermediate signal intensity corresponded to caseous necrosis, whereas high signal intensity related to granulomas or effusion. Postcontrast T1‐weighted images showed enhancement at the peripheries rather than the centers of tuberculous lesions. These results indicate that tuberculous arthritis should be included in the differential diagnosis when intra‐articular lesions with low or intermediate signal intensity are found on T2‐weighted images.
Angiogenic response of MCF7 human breast cancer to hormonal treatment: Assessment by dynamic GdDTPA‐enhanced MRI at high spatial resolution
Authors: Furman‐Haran Edna , Margalit Raanan , Maretzek António F. , Degani Hadassa 
Published: March 2007

AbstractDynamic gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA)‐enhanced MRI was followed during growth and regression of MCF7 human breast tumors implanted in nude mice in the presence of estrogen and tamoxifen, respectively. Gradient‐echo and spinecho sequences were applied at a temporal resolution of 12 and 100 seconds, respectively, and a spatial resolution of 195 × 390 × 1000 μm. Maps of initial rates of contrast enhancement demonstrated stimulation of local growth of permeable microcapillaries at regions bordering necrotic areas, resulting from tamoxifen treatment. This localized angiogenic stimulation was confirmed by immunohistochemical staining of endothelial cells. After 1 week of tamoxifen treatment, the fraction of tumor pixels exhibiting rapid initial rate of contrast enhancement increased significantly from .28 ± .05 to .46 ± .06. In parallel, the fraction of tumor area showing contrast enhancement 3 minutes after Gd‐DTPA injection also increased significantly, from .42 ± .06 to .58 ± .06. On the basis of these changes, it was possible to assess the response to tamoxifen therapy at an early stage.
MR imaging of silicone breast implants: Evaluation of prospective and retrospective interpretations and interobserver agreement
Authors: Quinn Stephen F. , Neubauer Nancy M. , Sheley Robert C. , Demlow Thomas A. , Szumowski Jerzy 
Published: March 2007

AbstractMR imaging was used to evaluate the integrity of silicone breast implants in 54 women with 108 implants. MR images were interpreted by relatively inexperienced readers who tried to reproduce the experiences reported in the literature. The study examines the interobserver agreement using different diagnostic signs and the influence of experience on interpretation errors. Prospective and retrospective interpretations were compared with surgical findings at the time of explantation. Diagnostic indicators, including the linguine sign, the inverted tear drop sign, the C sign, water droplets mixed with silicone, and extracapsular globules of silicone, were evaluated for diagnostic efficacy and interobserver agreement. The prospective sensitivity and specificity were 87% and 78%, respectively. With the retrospective interpretations, the sensitivity and specificity increased to 93% and 92%, respectively. Most of the prospective false‐positive interpretations were due to misinterpreting radial folds as signs of implant rupture. Six implants interpreted retrospectively as false positives had gross amounts of silicone around the implants at surgery but there were no obvious rents in the implant shells. There was fair to excellent interobserver agreement with the individual diagnostic signs except for extracapsular globules of silicone. All of the signs had specificities of greater than 90%. The sensitivities of the individual signs were less than the overall retrospective sensitivity. With experience, the sensitivity improved from 87% to 93% and the specificity improved from 78% to 92%. This study helps substantiate the use of diagnostic signs used by other authors to detect silicone loss from breast implants by MR imaging; however, questions remain as to the clinical role of MR imaging in evaluating implants for silicone loss.
High resolution 3D imaging of the inner ear with a modified fast spin‐echo pulse sequence
Authors: Lee James N. , King Brian D. , Parker Dennis L. , Buswell Henry R. , Harnsberger H. Ric 
Published: March 2007

AbstractA fast spin‐echo pulse sequence is described that produces high resolution images of the inner ear without susceptibility artifacts. It uses thin overlapping slices that can be reformatted in multiple projections to provide a view of the 3D geometry of inner ear structures, such as the cochlea, vestibule, semicircular canals, and internal auditory canal. It has proven useful in screening adults for the presence of acoustic schwannoma and in identifying structural congenital lesions in children with sensorineural hearing loss.