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Sample records for magnet weight supports

  1. Sliding weight supports for W7-X magnet system: structural aspects

    NASA Astrophysics Data System (ADS)

    Bykov, V.; Fellinger, J.; Egorov, K.; Schauer, F.; Köppen, M.; Jenzsch, H.

    2015-05-01

    The Wendelstein 7-X (W7-X) stellarator is presently under commissioning at the Max-Planck-Institut für Plasmaphysik in Greifswald. The coil system consisting of 70 superconducting coils of seven different types is supported by a massive central support structure (CSS), and thermally protected by the cryostat. The magnet system weight is borne by supports which are bolted to the cold CSS. These ten so-called cryo-legs penetrate through the cryostat wall to the warm machine base. The design of the cryo-legs incorporates glass-reinforced plastic tubes to guarantee relatively small thermal conductivity. In order to ensure free thermal shrinkage of the magnet system and to reduce stresses in the cryo-legs, sliding and rotating bearings are used as interfaces to the machine base. Tie-rods between the machine base and the warm ends of the cryo-legs prevent toroidal rotation of the magnet system, as well as any other horizontal shifts due to asymmetric loads. The assembly of the magnet system introduced some vertical imperfections in the cryo-leg positions causing considerable additional internal stresses which were not considered during the design stage. In addition, originally not planned trim coils induce unsymmetrical cyclic loads. Therefore, the previously used method to analyse one magnet system module with periodical boundary conditions is not applicable. Consequently, a model of the complete magnet system, including all five modules, was created and analysed. Fatigue analyses of the cryo-legs under the new cyclic loads, applied on top of the approximately 100 t static weight, have been performed in order to evaluate the lifetime. The paper presents the progress in structural analyses of the W7-X magnet system under the as-built conditions, loads due to the trim coil operation, and results of the weight support fatigue analysis.

  2. Magnetic record support

    NASA Technical Reports Server (NTRS)

    Nakayama, M.; Morita, H.; Tokuoka, Y.; Izumi, T.; Fukuda, K.; Kubota, Y.

    1984-01-01

    The magnetic layer of a magnetic record support is coated with a thin film of a polymer with a siloxane bond. The magnetic layer consists of a thin film obtained by vacuum metallization, cathode sputtering or dispersion of a ferromagnetic metal powder in a binder. The polymer with a siloxane bond is produced by the polymerization of an organic silicon compound which inherently contains or is able to form this bond. Polymerization is preferably performed by plasma polymerization.

  3. A novel mechatronic body weight support system.

    PubMed

    Frey, Martin; Colombo, Gery; Vaglio, Martino; Bucher, Rainer; Jörg, Matthias; Riener, Robert

    2006-09-01

    A novel mechatronic body weight support (BWS) system has been developed to provide precise body weight unloading for patients with neurological or other impairments during treadmill training. The system is composed of a passive elastic spring element to take over the main unloading force and an active closed-loop controlled electric drive to generate the exact desired force. Both force generating units, the passive spring and the active electric drive, act on the patient via a polyester rope connected to a harness worn by the patient. The length of the rope can be adjusted with an electric winch to adapt the system to different patient sizes. The system is fully computer controlled. At unloading loads of up to 60 kg and walking speeds of up to 3.2 km/h, the mean unloading error and the maximum unloading error of the presented BWS system was less than 1 and 3 kg, respectively. The performance was compared with those of two purely passive BWS systems currently being used by most other rehabilitation groups. This comprised counterweight systems and static BWS systems with fixed rope lengths. Counterweight systems reached mean and maximum unloading errors of up to 5.34 and 16.22 kg, respectively. The values for the static BWS were 11.02 kg and 27.67 kg, respectively. The novel mechatronic BWS system presented in this study adjusts desired unloading changes of up to 20 kg within less than 100 ms. Thus, not only constant BWS, but also gait cycle dependent or time variant oscillations of the desired force can be realized with high accuracy. Precise and constant unloading force is believed to be an important prerequisite for BWS gait therapy, where it is important to generate physiologically correct segmental dynamics and ground reaction forces. Thus, the novel BWS system presented in this paper is an important contribution to maximize the therapeutic outcome of human gait rehabilitation.

  4. Autonomy Support, Self-Regulation, and Weight Loss

    PubMed Central

    Gorin, Amy A.; Powers, Theodore A.; Koestner, Richard; Wing, Rena R.; Raynor, Hollie A.

    2015-01-01

    Objective Social support is believed to contribute to weight loss success, yet the type of support received is rarely assessed. To develop more effective weight loss interventions, examinations of the types of support that are associated with positive outcomes are needed. Self-Determination Theory suggests that support for an individual’s autonomy is beneficial and facilitates internalization of autonomous self-regulation. We examined whether autonomy support and directive forms of support were associated with weight loss outcomes in a larger randomized controlled trial. Method Adults (N = 201; 48.9 ± 10.5 years; 78.1% women) participating in a weight loss trial were assessed at 0, 6, and 18 months. Autonomy support (AS), directive support, and autonomous self-regulation (ASR) were measured at 0 and 6 months and examined in relation to 18-month weight loss outcomes. Results Baseline AS and ASR did not predict outcomes; however, AS and ASR at 6 months positively predicted 18-month weight losses (ps < .05), encouragement of healthy eating at 6 months was negatively related to 18-month weight losses (p < .01), and other forms of directive support were not associated with outcomes. Conclusions Autonomy support predicted better weight loss outcomes while some forms of directive support hindered progress. Weight loss trials are needed to determine whether family members and friends can be trained to provide autonomy support and whether this is more effective than programs targeting more general or directive forms of support. PMID:23730718

  5. Family support and weight-loss strategies among adolescents reporting sustained weight loss.

    PubMed

    Utter, Jennifer; Denny, Simon; Dixon, Robyn; Ameratunga, Shanthi; Teevale, Tasileta

    2013-03-01

    The current research aims to describe the weight-control strategies and family support for young people reporting sustained weight loss in a large, population-based sample. Data were collected as part of Youth'07, a nationally representative survey of the health and well-being of New Zealand youth. New Zealand secondary schools, 2007. Secondary-school students (n 9107). Among young people who attempted weight loss in the previous year, 51% reported long-term weight loss (lost weight and maintained weight loss for 6 months). Students reporting long-term weight loss were more likely to be male, but did not differ by age, ethnicity, socio-economic deprivation or measured weight status from students who reported temporary/recent weight loss or no weight loss. Students with long-term weight loss also reported healthier weight-control strategies (e.g., exercising, eating fewer fatty foods, eating fewer sweets), high parental support for healthy eating/activity and were less likely to report being teased about their weight by their family and having junk food available at home than students with temporary/recent weight loss or no weight loss. Approximately 50% of young people attempting weight loss reported sustained weight loss. Young people who reported sustained weight loss appeared to have more family support than those who did not achieve this, suggesting the importance for weight-control services and interventions in adolescents of actively engaging the family.

  6. Partial weight support differentially affects corticomotor excitability across muscles of the upper limb

    PubMed Central

    Runnalls, Keith D.; Anson, Greg; Wolf, Steven L.; Byblow, Winston D.

    2014-01-01

    Abstract Partial weight support may hold promise as a therapeutic adjuvant during rehabilitation after stroke by providing a permissive environment for reducing the expression of abnormal muscle synergies that cause upper limb impairment. We explored the neurophysiological effects of upper limb weight support in 13 healthy young adults by measuring motor‐evoked potentials (MEPs) from transcranial magnetic stimulation (TMS) of primary motor cortex and electromyography from anterior deltoid (AD), biceps brachii (BB), extensor carpi radialis (ECR), and first dorsal interosseous (FDI). Five levels of weight support, varying from none to full, were provided to the arm using a commercial device (Saebo Mobile Arm Support). For each level of support, stimulus–response (SR) curves were derived from MEPs across a range of TMS intensities. Weight support affected background EMG activity in each of the four muscles examined (P <0.0001 for each muscle). Tonic background activity was primarily reduced in the AD. Weight support had a differential effect on the size of MEPs across muscles. After curve fitting, the SR plateau for ECR increased at the lowest support level (P =0.004). For FDI, the SR plateau increased at the highest support level (P =0.0003). These results indicate that weight support of the proximal upper limb modulates corticomotor excitability across the forearm and hand. The findings support a model of integrated control of the upper limb and may inform the use of weight support in clinical settings. PMID:25501435

  7. Weight minimization of a support structure

    NASA Technical Reports Server (NTRS)

    Kluberdanz, Donald J.; Segalman, Helaine J.

    1990-01-01

    This paper addresses the weight minimization of a circular plate-like structure which resulted in a 26 percent weight reduction. The optimization was performed numerically with the COPES/ADS program using the modified method of feasible directions. Design parameters were the inner thickness and outer thickness of the plate with constraints on maximum yield stress and maximum transverse displacement. Also, constraints were specified for the upper and lower bounds of the fundamental frequency and plate thicknesses. The MSC/NASTRAN finite element program was used for the evaluation of response variables. Original and final designs of the plate were tested using an Instron tension-compression machine to compare finite element results to measured strain data. The difference between finite element strain components and measured strain data was within engineering accuracy.

  8. Public Support for Weight-Related Antidiscrimination Laws and Policies.

    PubMed

    Hilbert, Anja; Hübner, Claudia; Schmutzer, Gabriele; Danielsdottir, Sigrun; Brähler, Elmar; Puhl, Rebecca

    2017-01-01

    Weight-related discrimination is prevalent and associated with health impairments for those who are targeted, which underscores the need of antidiscrimination legislation. This study is the first to examine public support of weight-related antidiscrimination laws or policies in Germany, compared to the US and Iceland. In a representative German population sample (N = 2,513), public support for general and employment-specific weight-related antidiscrimination policies, weight-based victimization, and weight bias internalization were measured through established self-report questionnaires. Half of the German population sample agreed with antidiscrimination policies. General antidiscrimination laws received lower support than employment-specific laws. Support for policies considering obesity a physical disability was greatest in Germany, whereas support for employment-specific antidiscrimination laws was lower in Germany than in the US and Iceland. Total support for weight-related antidiscrimination policies was significantly predicted by lower age, female gender, obese weight status, residence in West Germany, church membership, and readiness to vote in elections. German support for weight-related antidiscrimination policies is moderate. Increasing awareness about weight-related discrimination and laws prohibiting this behavior may help to promote policy acceptance. © 2017 The Author(s) Published by S. Karger GmbH, Freiburg.

  9. Measuring social support for weight loss in an internet weight loss community.

    PubMed

    Hwang, Kevin O; Ottenbacher, Allison J; Lucke, Joseph F; Etchegaray, Jason M; Graham, Amanda L; Thomas, Eric J; Bernstam, Elmer V

    2011-02-01

    Although overweight and obese individuals are turning to Internet communities for social support for weight loss, there is no validated online instrument for measuring the subjective social support experiences of participants in these communities. The authors' objective was to determine whether an online version of a validated paper questionnaire, the Weight Management Support Inventory, is appropriate for measuring social support among members of Internet weight loss communities. The authors administered the paper and online versions of the questionnaire in random, counterbalanced fashion to 199 members of a large Internet weight loss community. Scores for the paper and online versions were comparable in between-subjects and within-subjects comparisons. Convergent validity is suggested by the finding that participants who posted messages on Internet forums several times per day reported more social support than those who posted less frequently. However, the instrumental (tangible) support items did not load significantly on the instrumental support factor, suggesting that instrumental support is not relevant to the social support exchanged among participants in these communities. The authors conclude that the online, modified Weight Management Support Inventory, without items for instrumental support, is an appropriate instrument for measuring social support for weight loss among members of Internet weight loss communities.

  10. The role of social support in weight loss maintenance: results from the MedWeight study.

    PubMed

    Karfopoulou, Eleni; Anastasiou, Costas A; Avgeraki, Evangelia; Kosmidis, Mary H; Yannakoulia, Mary

    2016-06-01

    The role of social support in weight management is not fully understood, as more support has been linked to both favorable and unfavorable outcomes. We examined social support in relation to weight loss maintenance, comparing between maintainers and regainers of weight loss. The MedWeight study is a Greek registry of people who have intentionally lost ≥10 % of their weight and are either maintaining this loss for over a year (maintainers), or have regained weight (regainers). Demographics and lifestyle habits questionnaires are completed online. Dietary assessment is carried out by two telephone 24 h recalls. Perceived social support was assessed by validated scales examining support from family and friends regarding healthy eating and exercise. 289 maintainers and 122 regainers participated. Regainers received more support compared to maintainers. However, maintainers reported receiving compliments and active participation, whereas regainers receiving verbal instructions and encouragements. Maintainers who received diet support displayed improved dietary intakes, such as lower energy intake; regainers' diet was unaffected by support. Positive, rather than instructive, support appears beneficial in weight loss maintenance.

  11. Weight loss support seeking on twitter: the impact of weight on follow back rates and interactions.

    PubMed

    May, Christine N; Waring, Molly E; Rodrigues, Stephanie; Oleski, Jessica L; Olendzki, Effie; Evans, Martinus; Carey, Jennifer; Pagoto, Sherry L

    2017-03-01

    People seek weight loss support on online social networks, but little is known about how to build a supportive community. We created four Twitter accounts portraying women interested in weight loss (two obese, two normal weight/overweight) and followed health care professional and peer accounts for 2-5 weeks. We examined follow back rates, interactions, and organic follows from professionals and peers by weight status. Follow back rates did not differ by weight status when following professionals (6.8 % normal weight/overweight vs 11.0 % for obese; p = 0.4167) or peers (6.7 % for normal weight/overweight vs 10.8 % for obese; p = 0.1548). Number of interactions and organic followers also did not differ by weight status. Peers interacted with study accounts significantly more than professionals (p = 0.0138), but interactions were infrequent. Women seeking weight loss support on Twitter may need to be present for more than 5 weeks to build an interactive weight loss community.

  12. Magnetic Support of Magnetic Fluid Droplet against Flow

    NASA Astrophysics Data System (ADS)

    Yamane, R.; Sakiyama, N.; Park, M. K.

    The magnetic droplet should be held in position against the flow of the blood for the magnetic drug targeting. In the present research, as the basis of this problem three types of experiments were conducted. In the first and the second experiments, a two-dimensional and a three-dimensional droplet are placed on the inclined flat plate and are supported by the magnetic force against the gravity. The maximum inclination for the droplet to flow down is measured. In the third experiment, a two-dimensional droplet is placed on the floor of the channel and is held in position by the magnetic force against the flow of the water. The droplet itself can be held at the position of the magnet, but, as the flow is faster, the spikes on the droplet move downstream with the water flow as if they rotate around the droplet.

  13. Hardware friendly adaptive support-weight approach for stereo matching

    NASA Astrophysics Data System (ADS)

    Hou, Zuoxun; Han, Pei; Zhang, Hongwei; An, Ran

    2016-10-01

    In this paper, the hardware friendly adaptive support-weight approach is proposed to simplify the weight calculation process of the standard approach, which employs the support region to simplify the calculation of the similarity and uses the fixed distance dependent weight to present the proximity. In addition, the complete stereo matching algorithm and the hardware structure for FPGA implementation compatible with the approach is proposed. The experimental results show that the algorithm produces the disparity map accurately in different illumination conditions and different scenes, and its processing average bad pixel rate is only 6.65% for the standard test images of the Middlebury database, which is approximate to the performance of the standard adaptive support-weight approach. The proposed hardware structure provides a basis for design and implementation of real-time accurate stereo matching FPGA system.

  14. Nutritional support of very low birth weight newborns.

    PubMed

    Ditzenberger, Georgia

    2009-06-01

    Nutritional support to promote optimal postnatal growth for very low birth weight (VLBW) newborns less than 1500 g at birth during the initial prolonged hospitalization is a significant issue. This article reviews the concepts involved in the nutritional support of VLBW newborns, including definitions and discussions of growth, optimal postnatal growth, body composition, initial weight loss, growth expectations, growth assessment tools used during the postnatal period, the relation between inadequate nutrition and neurodevelopment, the relation between protein intake and cognitive outcome, postnatal nutrition balance, the potential for programming of future adult-onset chronic conditions, a review of fetal nutritional intake, and current recommendations for nutritional support of VLBW newborns.

  15. Weighted K-means support vector machine for cancer prediction.

    PubMed

    Kim, SungHwan

    2016-01-01

    To date, the support vector machine (SVM) has been widely applied to diverse bio-medical fields to address disease subtype identification and pathogenicity of genetic variants. In this paper, I propose the weighted K-means support vector machine (wKM-SVM) and weighted support vector machine (wSVM), for which I allow the SVM to impose weights to the loss term. Besides, I demonstrate the numerical relations between the objective function of the SVM and weights. Motivated by general ensemble techniques, which are known to improve accuracy, I directly adopt the boosting algorithm to the newly proposed weighted KM-SVM (and wSVM). For predictive performance, a range of simulation studies demonstrate that the weighted KM-SVM (and wSVM) with boosting outperforms the standard KM-SVM (and SVM) including but not limited to many popular classification rules. I applied the proposed methods to simulated data and two large-scale real applications in the TCGA pan-cancer methylation data of breast and kidney cancer. In conclusion, the weighted KM-SVM (and wSVM) increases accuracy of the classification model, and will facilitate disease diagnosis and clinical treatment decisions to benefit patients. A software package (wSVM) is publicly available at the R-project webpage (https://www.r-project.org).

  16. DC Control Effort Minimized for Magnetic-Bearing-Supported Shaft

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2001-01-01

    A magnetic-bearing-supported shaft may have a number of concentricity and alignment problems. One of these involves the relationship of the position sensors, the centerline of the backup bearings, and the magnetic center of the magnetic bearings. For magnetic bearings with permanent magnet biasing, the average control current for a given control axis that is not bearing the shaft weight will be minimized if the shaft is centered, on average over a revolution, at the magnetic center of the bearings. That position may not yield zero sensor output or center the shaft in the backup bearing clearance. The desired shaft position that gives zero average current can be achieved if a simple additional term is added to the control law. Suppose that the instantaneous control currents from each bearing are available from measurements and can be input into the control computer. If each control current is integrated with a very small rate of accumulation and the result is added to the control output, the shaft will gradually move to a position where the control current averages to zero over many revolutions. This will occur regardless of any offsets of the position sensor inputs. At that position, the average control effort is minimized in comparison to other possible locations of the shaft. Nonlinearities of the magnetic bearing are minimized at that location as well.

  17. DC Control Effort Minimized for Magnetic-Bearing-Supported Shaft

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2001-01-01

    A magnetic-bearing-supported shaft may have a number of concentricity and alignment problems. One of these involves the relationship of the position sensors, the centerline of the backup bearings, and the magnetic center of the magnetic bearings. For magnetic bearings with permanent magnet biasing, the average control current for a given control axis that is not bearing the shaft weight will be minimized if the shaft is centered, on average over a revolution, at the magnetic center of the bearings. That position may not yield zero sensor output or center the shaft in the backup bearing clearance. The desired shaft position that gives zero average current can be achieved if a simple additional term is added to the control law. Suppose that the instantaneous control currents from each bearing are available from measurements and can be input into the control computer. If each control current is integrated with a very small rate of accumulation and the result is added to the control output, the shaft will gradually move to a position where the control current averages to zero over many revolutions. This will occur regardless of any offsets of the position sensor inputs. At that position, the average control effort is minimized in comparison to other possible locations of the shaft. Nonlinearities of the magnetic bearing are minimized at that location as well.

  18. Support Needs of Overweight African American Women for Weight Loss

    ERIC Educational Resources Information Center

    Thomas, Janet L.; Stewart, Diana W.; Lynam, Ian M.; Daley, Christine M.; Befort, Christie; Scherber, Robyn M.; Mercurio, Andrea E.; Okuyemi, Kolawole S.; Ahluwalia, Jasjit S.

    2009-01-01

    Objectives: To examine social support needs of obese and overweight African American women for weight loss. Methods: Focus groups were conducted with overweight and obese African American women. Data were analyzed using standard grounded theory text analysis. Results: Our middle-aged (45.7 years; SD = 12.6) women (N = 66) were interested in…

  19. Support Needs of Overweight African American Women for Weight Loss

    ERIC Educational Resources Information Center

    Thomas, Janet L.; Stewart, Diana W.; Lynam, Ian M.; Daley, Christine M.; Befort, Christie; Scherber, Robyn M.; Mercurio, Andrea E.; Okuyemi, Kolawole S.; Ahluwalia, Jasjit S.

    2009-01-01

    Objectives: To examine social support needs of obese and overweight African American women for weight loss. Methods: Focus groups were conducted with overweight and obese African American women. Data were analyzed using standard grounded theory text analysis. Results: Our middle-aged (45.7 years; SD = 12.6) women (N = 66) were interested in…

  20. Isotropic anomalous filtering in Diffusion-Weighted Magnetic Resonance Imaging.

    PubMed

    da S Senra Filho, Antonio Carlos; Jinzenji Duque, Juliano; Murta Junior, Luiz Otávio

    2013-01-01

    Noise is inherent to Diffusion-Weighted Magnetic Resonance Imaging (DWI) and noise reduction methods are necessary. Although process based on classical diffusion is one of the most used approaches for digital image, anomalous diffusion has the potential for image enhancement and it has not been tested for DWI noise reduction. This study evaluates Anomalous Diffusion (AD) filter as DWI enhancement method. The proposed method was applied to magnetic resonance diffusion weighted images (DW-MRI) with different noise levels. Results show better performance for anomalous diffusion when compared to classical diffusion approach. The proposed method has shown potential in DWI enhancement and can be an important process to improve quality in DWI for neuroimage-based diagnosis.

  1. [Reasons for losing weight: Why have programed support?].

    PubMed

    Jiménez-López, José Luis; Maldonado-Guzmán, María Elena; Flores-Pérez Pastén, Leticia; Déciga-García, Eduardo

    2012-01-01

    Obesity has increased in the entire World in recent decades. The increased incidence has put in doubt the efficacy of weight-control programs; therefore the study of this phenomenon has been focused in psychological reasons that have influence in the response to those programs. The aim of this study was to explore what were the patient's motives in a weight-loss program. the qualitative method to analyze the experience was performed. The focus group included ten patients with one investigator as an active observer, and 12 weekly sessions. We identified motives related with aesthetic that could benefit success, and unrealistic expectations that could lead to failure after the strategy was completed. the encouraging of certain motives could keep success of weight-loss programs. It is needed more qualitative research to support this conclusion and quantitative research to confirm it.

  2. Peer support enhanced social support in adolescent females during weight loss.

    PubMed

    Kulik, Noel L; Fisher, Edwin B; Ward, Dianne S; Ennett, Susan T; Bowling, J Michael; Tate, Deborah F

    2014-09-01

    To describe the development of a peer support intervention and test an enhanced version compared to a standard protocol. Participants (N = 36 females) were assigned to an Enhanced Peer Support (PS) vs Standard weight loss group for 4 months. The PS component consisted of skills training and practice between sessions using social networking. The PS group perceived significantly more peer support and experienced higher levels of social interaction. When meeting frequency decreased, the PS group showed an increase in overall types of support from group members. Findings suggest that an intervention targeting peer support skills results in greater feelings of peer support.

  3. Structural social support predicts functional social support in an online weight loss programme.

    PubMed

    Hwang, Kevin O; Etchegaray, Jason M; Sciamanna, Christopher N; Bernstam, Elmer V; Thomas, Eric J

    2014-06-01

    Online weight loss programmes allow members to use social media tools to give and receive social support for weight loss. However, little is known about the relationship between the use of social media tools and the perception of specific types of support. To test the hypothesis that the frequency of using social media tools (structural support) is directly related to perceptions of Encouragement, Information and Shared Experiences support (functional support). Online survey. Members of an online weight loss programme. The outcome was the perception of Encouragement (motivation, congratulations), Information (advice, tips) and Shared Experiences (belonging to a group) social support. The predictor was a social media scale based on the frequency of using forums and blogs within the online weight loss programme (alpha = 0.91). The relationship between predictor and outcomes was evaluated with structural equation modelling (SEM) and logistic regression, adjusted for sociodemographic characteristics, BMI and duration of website membership. The 187 participants were mostly female (95%) and white (91%), with mean (SD) age 37 (12) years and mean (SD) BMI 31 (8). SEM produced a model in which social media use predicted Encouragement support, but not Information or Shared Experiences support. Participants who used the social media tools at least weekly were almost five times as likely to experience Encouragement support compared to those who used the features less frequently [adjusted OR 4.8 (95% CI 1.8-12.8)]. Using the social media tools of an online weight loss programme at least once per week is strongly associated with receiving Encouragement for weight loss behaviours. © 2011 John Wiley & Sons Ltd.

  4. [Effects of a weight loss program with group participation supported by strengthened social support].

    PubMed

    Kubota, Akio; Nagata, Junko; Sugiyama, Masumi

    2008-05-01

    The purpose of this study was to examine the efficacy of a weight loss program with group participation supported by strengthened social support (hereafter termed the Weight Loss Rally). Thirty-eight groups (41 males, 73 females) with a BMI of more than 22 kg/m2 living or working in Shizuoka Prefecture participated in the Weight Loss Rally. In order to strengthen social support, group participation approaches were taken instead of an individual participation approach. In the Weight Loss Rally, the weight changes of each group were monitored for twelve weeks with a goal of reducing 5% of their initial weight. In addition, the average steps taken per day, the average achievement rate for exercise, and attainment of diet objectives were assessed at the same time. All evaluations with other characteristics, such as remuneration and communication systems, were made on a group rather than an individual basis. In order to confrim the benefit of the Weight Loss Rally, physical measurements of all participants were taken and questionnaires were administered before and after the program. Complete data were obtained for 32 groups (35 males, 61 females). An average of 3.7 kg weight loss was observed for a total of 96 men and women (92.7%) along with increase of physical activity and decreased dietary intake (P < 0.001). An average of 1.4 kg/m2 decrease in BMI, an average of 2.8% decrease in body fat percentage, and an average of 3.9 cm reduction in waist circumference were reported (P < 0.001). According to the results of the questionnaires, 91 participants (94.8%) answered that they felt comfortable with the group participation toward the Weight Loss Rally. Other grouping methods were also used to analyze the results. First, group of colleagues, friends and family members were compared. Second, males, females and mixed groups were also compared for analysis. For every group similar results such as decrease in weight, BMI, body fat percentage, and waist circumference were

  5. Magnetic Support and Fragmentation of Molecular Clouds

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.; Pudritz, R. E.

    1990-12-01

    Molecular clouds contain magnetic fields with energies comparable to their gravitational binding energies. In the dynamic environment of the interstellar medium, strong hydromagnetic waves are excited in this field on wavelengths longer than the ion-neutral mean free path. In a typical molecular cloud this length-scale, λmin, is of the order of 10-1 of the cloud size. On shorter length-scales the gas is without wave pressure support, and can flow down field lines. The joint effects of excess gravity and flux leakage causes a local dynamic collapse. We test our ideas with a detailed -body calculation in which we impose MHD waves on an initially uniform isothermal gas cloud. The effect of magnetic fields is included in our calculation by the frictional drag on the dominant, neutral population. In the absence of MHD waves the cloud fragments slightly while collapsing, then merges together at the centre into a single, pressure-supported, flattened object. We impose a spectrum of large amplitude Alfvén waves whose velocity amplitude varies as k-3/2, where k is the wavenumber. The initial background magnetic field is chosen to have an energy density slightly larger than the gravitational energy density. The damping is assumed to be balanced by a continuous external supply of wave energy. The simulation shows that the magnetic field and hydromagnetic waves provide sufficient support against gravity so that the cloud undergoes a global, isotropic contraction at a quarter the free-fall rate. The shortest wave present, λ≍λmin, sets the minimum fragment mass, for small Jeans masses. We follow the evolution of fragments having a minimum overdensity of 30 (corresponding to a mass m ≥ 0.4 × 10-3 Mcloud). The fragments appear quickly, and then agglomerate together, yielding an evolving mass spectrum that remains approximately a power law, dN/dm ∝ m-α, where a is 2.5 ± 0.5. Several specific tests of this theory are proposed: (i) that a short wavelength cut

  6. Aging and partial body weight support affects gait variability

    PubMed Central

    Kyvelidou, Anastasia; Kurz, Max J; Ehlers, Julie L; Stergiou, Nicholas

    2008-01-01

    Background Aging leads to increases in gait variability which may explain the large incidence of falls in the elderly. Body weight support training may be utilized to improve gait in the elderly and minimize falls. However, before initiating rehabilitation protocols, baseline studies are needed to identify the effect of body weight support on elderly gait variability. Our purpose was to determine the kinematic variability of the lower extremities in young and elderly healthy females at changing levels of body weight support during walking. Methods Ten young and ten elderly females walked on a treadmill for two minutes with a body weight support (BWS) system under four different conditions: 1 g, 0.9 g, 0.8 g, and 0.7 g. Three-dimensional kinematics was captured at 60 Hz with a Peak Performance high speed video system. Magnitude and structure of variability of the sagittal plane angular kinematics of the right lower extremity was analyzed using both linear (magnitude; standard deviations and coefficient of variations) and nonlinear (structure; Lyapunov exponents) measures. A two way mixed ANOVA was used to evaluate the effect of age and BWS on variability. Results Linear analysis showed that the elderly presented significantly more variability at the hip and knee joint than the young females. Moreover, higher levels of BWS presented increased variability at all joints as found in both the linear and nonlinear measures utilized. Conclusion Increased levels of BWS increased lower extremity kinematic variability. If the intent of BWS training is to decrease variability in gait patterns, this did not occur based on our results. However, we did not perform a training study. Thus, it is possible that after several weeks of training and increased habituation, these initial increased variability values will decrease. This assumption needs to be addressed in future investigation with both "healthy" elderly and elderly fallers. In addition, it is possible that BWS training can

  7. The Ganong paradigm: Converging evidence supporting initial phoneme weighting

    NASA Astrophysics Data System (ADS)

    Tracy, Erik C.; Pitt, Mark A.

    2003-10-01

    In the present experiment we investigate whether the initial phoneme is given more weight in word recognition [W. D. Marslen-Wilson and A. Welsh, Cognit. Psych. 10, 29-63 (1978)] or if all phonemes in a word are weighted equally [C. M. Connine, D. G. Blasko, and D. Titone, J. Mem. Lang. 32, 193-210 (1993)]. Using the Ganong paradigm [W. F. Ganong, JEP:HPP. 6, 110-125 (1980)], participants were instructed to categorize a final ambiguous fricative in the target items, which included both words and pseudowords. Pseudowords were created by changing either the initial or a medial phoneme within the words. For example, the word diminish was altered to create the pseudowords timinish and dimimish. In addition, initial and medial phonemes were altered by either one or three distinctive features. The differences in the labeling of the final ambiguous fricative in the target items led to the conclusion that the initial phoneme is weighted more heavily. [Work supported by NIDCD.

  8. Functionalized magnetic nanoparticles: A novel heterogeneous catalyst support

    EPA Science Inventory

    Functionalized magnetic nanoparticles have emerged as viable alternatives to conventional materials, as robust, high-surface-area heterogeneous catalyst supports. Post-synthetic surface modification protocol for magnetic nanoparticles has been developed that imparts desirable che...

  9. Functionalized magnetic nanoparticles: A novel heterogeneous catalyst support

    EPA Science Inventory

    Functionalized magnetic nanoparticles have emerged as viable alternatives to conventional materials, as robust, high-surface-area heterogeneous catalyst supports. Post-synthetic surface modification protocol for magnetic nanoparticles has been developed that imparts desirable che...

  10. Weighted averages of magnetization from magnetic field measurements: A fast interpretation tool

    NASA Astrophysics Data System (ADS)

    Fedi, Maurizio

    2003-08-01

    Magnetic anomalies may be interpreted in terms of weighted averages of magnetization (WAM) by a simple transformation. The WAM transformation consists of dividing at each measurement point the experimental magnetic field by a normalizing field, computed from a source volume with a homogeneous unit-magnetization. The transformation yields a straightforward link among source and field position vectors. A main WAM outcome is that sources at different depths appear well discriminated. Due to the symmetry of the problem, the higher the considered field altitude, the deeper the sources outlined by the transformation. This is shown for single and multi-source synthetic cases as well as for real data. We analyze the real case of Mt. Vulture volcano (Southern Italy), where the related anomaly strongly interferes with that from deep intrusive sources. The volcanic edifice is well identified. The deep source is estimated at about 9 km depth, in agreement with other results.

  11. Support for linguistic macrofamilies from weighted sequence alignment

    PubMed Central

    Jäger, Gerhard

    2015-01-01

    Computational phylogenetics is in the process of revolutionizing historical linguistics. Recent applications have shed new light on controversial issues, such as the location and time depth of language families and the dynamics of their spread. So far, these approaches have been limited to single-language families because they rely on a large body of expert cognacy judgments or grammatical classifications, which is currently unavailable for most language families. The present study pursues a different approach. Starting from raw phonetic transcription of core vocabulary items from very diverse languages, it applies weighted string alignment to track both phonetic and lexical change. Applied to a collection of ∼1,000 Eurasian languages and dialects, this method, combined with phylogenetic inference, leads to a classification in excellent agreement with established findings of historical linguistics. Furthermore, it provides strong statistical support for several putative macrofamilies contested in current historical linguistics. In particular, there is a solid signal for the Nostratic/Eurasiatic macrofamily. PMID:26403857

  12. Support for linguistic macrofamilies from weighted sequence alignment.

    PubMed

    Jäger, Gerhard

    2015-10-13

    Computational phylogenetics is in the process of revolutionizing historical linguistics. Recent applications have shed new light on controversial issues, such as the location and time depth of language families and the dynamics of their spread. So far, these approaches have been limited to single-language families because they rely on a large body of expert cognacy judgments or grammatical classifications, which is currently unavailable for most language families. The present study pursues a different approach. Starting from raw phonetic transcription of core vocabulary items from very diverse languages, it applies weighted string alignment to track both phonetic and lexical change. Applied to a collection of ∼1,000 Eurasian languages and dialects, this method, combined with phylogenetic inference, leads to a classification in excellent agreement with established findings of historical linguistics. Furthermore, it provides strong statistical support for several putative macrofamilies contested in current historical linguistics. In particular, there is a solid signal for the Nostratic/Eurasiatic macrofamily.

  13. Treadmill training and body weight support for walking after stroke.

    PubMed

    Mehrholz, Jan; Thomas, Simone; Elsner, Bernhard

    2017-08-17

    Treadmill training, with or without body weight support using a harness, is used in rehabilitation and might help to improve walking after stroke. This is an update of the Cochrane review first published in 2003 and updated in 2005 and 2014. To determine if treadmill training and body weight support, individually or in combination, improve walking ability, quality of life, activities of daily living, dependency or death, and institutionalisation or death, compared with other physiotherapy gait-training interventions after stroke. The secondary objective was to determine the safety and acceptability of this method of gait training. We searched the Cochrane Stroke Group Trials Register (last searched 14 February 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) and the Database of Reviews of Effects (DARE) (the Cochrane Library 2017, Issue 2), MEDLINE (1966 to 14 February 2017), Embase (1980 to 14 February 2017), CINAHL (1982 to 14 February 2017), AMED (1985 to 14 February 2017) and SPORTDiscus (1949 to 14 February 2017). We also handsearched relevant conference proceedings and ongoing trials and research registers, screened reference lists, and contacted trialists to identify further trials. Randomised or quasi-randomised controlled and cross-over trials of treadmill training and body weight support, individually or in combination, for the treatment of walking after stroke. Two review authors independently selected trials, extracted data, and assessed risk of bias and methodological quality. The primary outcomes investigated were walking speed, endurance, and dependency. We included 56 trials with 3105 participants in this updated review. The average age of the participants was 60 years, and the studies were carried out in both inpatient and outpatient settings. All participants had at least some walking difficulties and many could not walk without assistance. Overall, the use of treadmill training did not increase the chances of walking

  14. Partial weight support of the arm affects corticomotor selectivity of biceps brachii.

    PubMed

    Runnalls, Keith D; Anson, Greg; Byblow, Winston D

    2015-10-26

    Weight support of the arm (WS) can be used in stroke rehabilitation to facilitate upper limb therapy, but the neurophysiological effects of this technique are not well understood. While an overall reduction in muscle activity is expected, the mechanism by which WS may alter the expression of muscle synergies has not been examined until now. We explored the neurophysiological effect of WS on the selectivity of biceps brachii (BB) activation in healthy adults. Thirteen participants completed counterbalanced movement tasks in a repeated measures design. Three levels of WS (0, 45, and 90 % of full support) were provided to the arm using a commercial device (Saebo Mobile Arm Support). At each level of WS, participants maintained a flexed shoulder posture while performing rhythmic isometric elbow flexion (BB agonist) or forearm pronation (BB antagonist). Single-pulse transcranial magnetic stimulation of primary motor cortex was used to elicit motor-evoked potentials (MEPs) in BB 100-300 ms before muscle contraction. Baseline muscle activity and MEP amplitude were the primary dependent measures. Effects of movement TASK and SUPPORT LEVEL were statistically analyzed using linear mixed effects models. As expected, with increased support tonic activity was reduced across all muscles. This effect was greatest in the anti-gravity muscle anterior deltoid, and evident in biceps brachii and pronator teres as well. For BB MEP amplitude, TASK and SUPPORT LEVEL, interacted such that for elbow flexion, MEP amplitudes were smaller with incrementally greater WS whereas, for forearm pronation MEP amplitudes were smaller only at high WS. Weight support of the arm influences corticomotor selectivity of biceps brachii. WS may impact coordination independently of a global reduction in muscle activity. The amount of supportive force applied to the arm influences the neuromechanical control profile for the limb. These findings may inform the application of WS in upper limb stroke

  15. High-Field Superconducting Magnets Supporting PTOLEMY

    NASA Astrophysics Data System (ADS)

    Hopkins, Ann; Luo, Audrey; Osherson, Benjamin; Gentile, Charles; Tully, Chris; Cohen, Adam

    2013-10-01

    The Princeton Tritium Observatory for Light, Early Universe, Massive Neutrino Yield (PTOLEMY) is an experiment planned to collect data on Big Bang relic neutrinos, which are predicted to be amongst the oldest and smallest particles in the universe. Currently, a proof-of-principle prototype is being developed at Princeton Plasma Physics Laboratory to test key technologies associated with the experiment. A prominent technology in the experiment is the Magnetic Adiabatic Collimation with an Electrostatic Filter (MAC-E filter), which guides tritium betas along magnetic field lines generated by superconducting magnets while deflecting those of lower energies. B field mapping is performed to ensure the magnets produce a minimum field at the midpoint of the configuration of the magnets and to verify accuracy of existing models. Preliminary tests indicate the required rapid decrease in B field strength from the bore of the more powerful 3.35 T magnet, with the field dropping to 0.18 T approximately 0.5 feet from the outermost surface of the magnet.

  16. Diffusion-weighted magnetic resonance imaging in cystic renal masses

    PubMed Central

    Balyemez, Fikret; Aslan, Ahmet; Inan, Ibrahim; Ayaz, Ercan; Karagöz, Vildan; Özkanli, Sıdıka Şeyma; Acar, Murat

    2017-01-01

    Introduction: We aimed to introduce the diagnostic value of diffusion-weighted (DWI) magnetic resonance imaging (MRI) for distinguishing benign and malignant renal cystic masses. Methods: Abdominal DWI-MRIs of patients with Bosniak categories 2F, 3, and 4 cystic renal masses were evaluated retrospectively. Cystic masses were assigned as benign or malignant according to histopathological or followup MRI findings and compared with apparent diffusion coefficient (ADC) values. Results: There were 30 patients (18 males and 12 females, mean age was 59.23 ± 12.08 years [range 38–83 years]) with cystic renal masses (eight Bosniak category 2F, 12 Bosniak category 3, 10 Bosniak category 4). Among them, 14 cysts were diagnosed as benign and 16 as malignant by followup imaging or histopathological findings. For the malignant lesions, the mean ADC values were lower than for benign lesions (p=0.001). An ADC value of ≤2.28 ×10−6 mm2/s or less had a sensitivity of 75% and a specificity of 92.86% for detecting malignancy. Conclusions: ADC can improve the diagnostic performance of MRI in the evaluation of complex renal cysts when used together with conventional MRI sequences. PMID:28163806

  17. Legislating for weight-based equality: national trends in public support for laws to prohibit weight discrimination.

    PubMed

    Puhl, R M; Suh, Y; Li, X

    2016-08-01

    The prevalence of weight discrimination in the United States has led to increasing calls for legal measures to address weight-based inequities on a broader scale. This study examined public support in 2014 and 2015 for three proposed laws prohibiting weight discrimination, and compared findings with public attitudes towards the same laws from 2011 to 2013. An online survey was completed by a diverse national sample of US adults (N=2411) in June-July of 2014 and 2015 to assess their support for anti-discrimination legislation. Public support increased for the anti-discrimination laws from 2014 to 2015, and at least 71% of participants expressed support for each of the laws in both years. Compared with public support documented in 2011-2013, there was a significant increase in support in 2014-2015 for legislation to extend disability protections to individuals with obesity and for laws that would include body weight in existing state civil rights statutes. Consistently, high levels of support (78%) were documented across this 5-year period for laws to address weight-based discrimination in employment. As public approval is a powerful catalyst motivating political will needed to make policy changes, these findings provide important insights and implications for advancing policy-level discourse about remedies for weight discrimination.

  18. Dynamic formation and magnetic support of loop or arcade prominences

    NASA Technical Reports Server (NTRS)

    Vanhoven, Gerard; Mok, Y.; Drake, J. F.

    1992-01-01

    The results of model dynamic simulations of the formation and support of a narrow prominence at the apex of a coronal magnetic loop or arcade are described. The condensation process proceeds via an initial radiative cooling and pressure drop, and a secondary siphon flow from the dense chromospheric ends. The antibuoyancy effect as the prominence forms causes a bending of a confining magnetic field, which propagates toward the semirigid ends of the magnetic loop. Thus, a wide magnetic 'hammock' or well (of a normal polarity Kippenhahn-Schlueter type) is formed, which supports the prominence at or near the field apex.

  19. Smartphone applications to support weight loss: current perspectives

    PubMed Central

    Pellegrini, Christine A; Pfammatter, Angela F; Conroy, David E; Spring, Bonnie

    2015-01-01

    Lower cost alternatives are needed for the traditional in-person behavioral weight loss programs to overcome challenges of lowering the worldwide prevalence of overweight and obesity. Smartphones have become ubiquitous and provide a unique platform to aid in the delivery of a behavioral weight loss program. The technological capabilities of a smartphone may address certain limitations of a traditional weight loss program, while also reducing the cost and burden on participants, interventionists, and health care providers. Awareness of the advantages smartphones offer for weight loss has led to the rapid development and proliferation of weight loss applications (apps). The built-in features and the mechanisms by which they work vary across apps. Although there are an extraordinary number of a weight loss apps available, most lack the same magnitude of evidence-based behavior change strategies typically used in traditional programs. As features develop and new capabilities are identified, we propose a conceptual model as a framework to guide the inclusion of features that can facilitate behavior change and lead to reductions in weight. Whereas the conventional wisdom about behavior change asserts that more is better (with respect to the number of behavior change techniques involved), this model suggests that less may be more because extra techniques may add burden and adversely impact engagement. Current evidence is promising and continues to emerge on the potential of smartphone use within weight loss programs; yet research is unable to keep up with the rapidly improving smartphone technology. Future studies are needed to refine the conceptual model’s utility in the use of technology for weight loss, determine the effectiveness of intervention components utilizing smartphone technology, and identify novel and faster ways to evaluate the ever-changing technology. PMID:26236766

  20. Support vector machine classification of arterial volume-weighted arterial spin tagging images.

    PubMed

    Shah, Yash S; Hernandez-Garcia, Luis; Jahanian, Hesamoddin; Peltier, Scott J

    2016-12-01

    In recent years, machine-learning techniques have gained growing popularity in medical image analysis. Temporal brain-state classification is one of the major applications of machine-learning techniques in functional magnetic resonance imaging (fMRI) brain data. This article explores the use of support vector machine (SVM) classification technique with motor-visual activation paradigm to perform brain-state classification into activation and rest with an emphasis on different acquisition techniques. Images were acquired using a recently developed variant of traditional pseudocontinuous arterial spin labeling technique called arterial volume-weighted arterial spin tagging (AVAST). The classification scheme is also performed on images acquired using blood oxygenation-level dependent (BOLD) and traditional perfusion-weighted arterial spin labeling (ASL) techniques for comparison. The AVAST technique outperforms traditional pseudocontinuous ASL, achieving classification accuracy comparable to that of BOLD contrast images. This study demonstrates that AVAST has superior signal-to-noise ratio and improved temporal resolution as compared with traditional perfusion-weighted ASL and reduced sensitivity to scanner drift as compared with BOLD. Owing to these characteristics, AVAST lends itself as an ideal choice for dynamic fMRI and real-time neurofeedback experiments with sustained activation periods.

  1. Magnetic nanoparticle-supported glutathione: a conceptually sustainable organocatalyst

    EPA Science Inventory

    A conceptually novel nanoparticle-supported and magnetically recoverable organocatalyst has been developed, which is readily prepared from inexpensive starting materials in a truly sustainable manner; which catalyzes Paal-Knorr reaction with high yield in pure aqueous medium that...

  2. Is social support associated with greater weight loss after bariatric surgery?: a systematic review.

    PubMed

    Livhits, M; Mercado, C; Yermilov, I; Parikh, J A; Dutson, E; Mehran, A; Ko, C Y; Shekelle, P G; Gibbons, M M

    2011-02-01

    Social support may be associated with increased weight loss after bariatric surgery. The objective of this article is to determine impact of post-operative support groups and other forms of social support on weight loss after bariatric surgery. MEDLINE search (1988-2009) was completed using MeSH terms including bariatric procedures and a spectrum of patient factors with potential relationship to weight loss outcomes. Of the 934 screened studies, 10 reported on social support and weight loss outcomes. Five studies reported on support groups and five studies reported on other forms of social support (such as perceived family support or number of confidants) and degree of post-operative weight loss (total n = 735 patients). All studies found a positive association between post-operative support groups and weight loss. One study found a positive association between marital status (being single) and weight loss, while three studies found a non-significant positive trend and one study was inconclusive. Support group attendance after bariatric surgery is associated with greater post-operative weight loss. Further research is necessary to determine the impact of other forms of social support. These factors should be addressed in prospective studies of weight loss following bariatric surgery, as they may represent ways to improve post-operative outcomes. © 2010 The Authors. obesity reviews © 2010 International Association for the Study of Obesity.

  3. Magnetic resonance diffusion-weighted imaging: extraneurological applications.

    PubMed

    Colagrande, S; Carbone, S F; Carusi, L M; Cova, M; Villari, N

    2006-04-01

    Diffusion-weighted (Dw) imaging has for a number of years been a diagnostic tool in the field of neuroradiology, yet only since the end of the 1990s, with the introduction of echoplanar imaging (EPI) and the use of sequences capable of performing diffusion studies during a single breath hold, has it found diagnostic applications at the level of the abdomen. The inherent sensitivity to motion and the magnetic susceptibility of Dw sequences nonetheless still create problems in the study of the abdomen due to artefacts caused by the heartbeat and intestinal peristalsis, as well as the presence of various parenchymal-gas interfaces. With regard to focal liver lesions, a review of the literature reveals that Dw imaging is able to differentiate lesions with high water content (cysts and angiomas) from solid lesions. With regard to the latter, although there are differences between benign forms [focal nodular hyperplasia (FNH), adenoma] and malignant forms [metastasis, hepatocellular carcinoma (HCC)] in their apparent diffusion coefficient (ADC) in the average values for histological type, there is a significant overlap in values when lesions are assessed individually, with the consequent problem of their correct identification. One promising aspect is the possibility of quantifying the degree of fibrosis in patients with chronic liver disease and cirrhosis given that the deposit of collagen fibres "restricts" the motion of water molecules and therefore reduces ADC values. However, even in this field, studies can only be considered preliminary and far from real clinical applications. The retroperitoneum is less affected by motion artefacts and similarly deserves the attention of Dw imaging. Here it is possible to differentiate mucin-producing tumours of the pancreas from pseudocystic forms on the basis of ADC values even though the limited spatial resolution of Dw imaging does not enable the identification of small lesions. Dw imaging may be applied to the study of the

  4. Identifying the ischaemic penumbra using pH-weighted magnetic resonance imaging

    PubMed Central

    Harston, George W. J.; Tee, Yee Kai; Blockley, Nicholas; Okell, Thomas W.; Thandeswaran, Sivarajan; Shaya, Gabriel; Sheerin, Fintan; Cellerini, Martino; Payne, Stephen; Jezzard, Peter; Chappell, Michael

    2015-01-01

    The original concept of the ischaemic penumbra suggested imaging of regional cerebral blood flow and metabolism would be required to identify tissue that may benefit from intervention. Amide proton transfer magnetic resonance imaging, a chemical exchange saturation transfer technique, has been used to derive cerebral intracellular pH in preclinical stroke models and has been proposed as a metabolic marker of ischaemic penumbra. In this proof of principle clinical study, we explored the potential of this pH-weighted magnetic resonance imaging technique at tissue-level. Detailed voxel-wise analysis was performed on data from a prospective cohort of 12 patients with acute ischaemic stroke. Voxels within ischaemic core had a more severe intracellular acidosis than hypoperfused tissue recruited to the final infarct (P < 0.0001), which in turn was more acidotic than hypoperfused tissue that survived (P < 0.0001). In addition, when confined to the grey matter perfusion deficit, intracellular pH (P < 0.0001), but not cerebral blood flow (P = 0.31), differed between tissue that infarcted and tissue that survived. Within the presenting apparent diffusion coefficient lesion, intracellular pH differed between tissue with early apparent diffusion lesion pseudonormalization and tissue with true radiographic recovery. These findings support the need for further investigation of pH-weighted imaging in patients with acute ischaemic stroke. PMID:25564491

  5. Identifying the ischaemic penumbra using pH-weighted magnetic resonance imaging.

    PubMed

    Harston, George W J; Tee, Yee Kai; Blockley, Nicholas; Okell, Thomas W; Thandeswaran, Sivarajan; Shaya, Gabriel; Sheerin, Fintan; Cellerini, Martino; Payne, Stephen; Jezzard, Peter; Chappell, Michael; Kennedy, James

    2015-01-01

    The original concept of the ischaemic penumbra suggested imaging of regional cerebral blood flow and metabolism would be required to identify tissue that may benefit from intervention. Amide proton transfer magnetic resonance imaging, a chemical exchange saturation transfer technique, has been used to derive cerebral intracellular pH in preclinical stroke models and has been proposed as a metabolic marker of ischaemic penumbra. In this proof of principle clinical study, we explored the potential of this pH-weighted magnetic resonance imaging technique at tissue-level. Detailed voxel-wise analysis was performed on data from a prospective cohort of 12 patients with acute ischaemic stroke. Voxels within ischaemic core had a more severe intracellular acidosis than hypoperfused tissue recruited to the final infarct (P < 0.0001), which in turn was more acidotic than hypoperfused tissue that survived (P < 0.0001). In addition, when confined to the grey matter perfusion deficit, intracellular pH (P < 0.0001), but not cerebral blood flow (P = 0.31), differed between tissue that infarcted and tissue that survived. Within the presenting apparent diffusion coefficient lesion, intracellular pH differed between tissue with early apparent diffusion lesion pseudonormalization and tissue with true radiographic recovery. These findings support the need for further investigation of pH-weighted imaging in patients with acute ischaemic stroke.

  6. Case history of magnetic bearing supported hot gas turboexpander

    SciTech Connect

    Destombes, Y.; Allaire, P.E.

    1995-12-31

    A very significant advantage for the use of magnetic bearings in hot gas and cryogenic expanders is that the bearing operating temperature can be much higher or lower than for conventional oil lubricated fluid film or rolling element bearings. This has lead to the increasing development of industrial expanders which are magnetic bearing supported and rather complex bearing oil supply sealing arrangements can be eliminated. As advances in magnetic bearing technology and understanding occur, the design and performance of the magnetic bearings continues to improve. The purpose of this paper is to describe some characteristics of industrial magnetic bearing supported turboexpanders, both hot gas and cryogenic, and present a particular hot gas expander application. This paper discusses the basic principles of operation of the magnetic bearings including the bearing radial and thrust bearings, sensors, control system, and dynamic characteristics. The governing equations are given for upper quadrant radial bearing designs. Design equations relevant to bearing design will be presented to assist potential users of magnetic bearings in understanding their operation. The paper also presents a practical application of magnetic bearings to a hot gas turbogenerator. The bearings support a turbine wheel which converts the exhaust gas energy of a blast furnace into electrical power through a synchronous 6 MW generator. The magnetic bearing allowed the rotor to be constructed as a single shaft machine. The turbine wheel is directly connected to the generator rotor. The unit has been successfully operated for a 8 year period and now has in excess of 70,000 hours in a steel plant in Europe. It has some unique features: (1) it is the heaviest magnetic bearing supported rotor in industrial operation at 8 tons, (2) it has very high unbalance acceptance, (3) it has a special rotor mounted auxiliary bearing design, and (4) only the upper quadrant of the bearing is employed in the unit.

  7. Random synaptic feedback weights support error backpropagation for deep learning

    PubMed Central

    Lillicrap, Timothy P.; Cownden, Daniel; Tweed, Douglas B.; Akerman, Colin J.

    2016-01-01

    The brain processes information through multiple layers of neurons. This deep architecture is representationally powerful, but complicates learning because it is difficult to identify the responsible neurons when a mistake is made. In machine learning, the backpropagation algorithm assigns blame by multiplying error signals with all the synaptic weights on each neuron's axon and further downstream. However, this involves a precise, symmetric backward connectivity pattern, which is thought to be impossible in the brain. Here we demonstrate that this strong architectural constraint is not required for effective error propagation. We present a surprisingly simple mechanism that assigns blame by multiplying errors by even random synaptic weights. This mechanism can transmit teaching signals across multiple layers of neurons and performs as effectively as backpropagation on a variety of tasks. Our results help reopen questions about how the brain could use error signals and dispel long-held assumptions about algorithmic constraints on learning. PMID:27824044

  8. Random synaptic feedback weights support error backpropagation for deep learning

    NASA Astrophysics Data System (ADS)

    Lillicrap, Timothy P.; Cownden, Daniel; Tweed, Douglas B.; Akerman, Colin J.

    2016-11-01

    The brain processes information through multiple layers of neurons. This deep architecture is representationally powerful, but complicates learning because it is difficult to identify the responsible neurons when a mistake is made. In machine learning, the backpropagation algorithm assigns blame by multiplying error signals with all the synaptic weights on each neuron's axon and further downstream. However, this involves a precise, symmetric backward connectivity pattern, which is thought to be impossible in the brain. Here we demonstrate that this strong architectural constraint is not required for effective error propagation. We present a surprisingly simple mechanism that assigns blame by multiplying errors by even random synaptic weights. This mechanism can transmit teaching signals across multiple layers of neurons and performs as effectively as backpropagation on a variety of tasks. Our results help reopen questions about how the brain could use error signals and dispel long-held assumptions about algorithmic constraints on learning.

  9. Random synaptic feedback weights support error backpropagation for deep learning.

    PubMed

    Lillicrap, Timothy P; Cownden, Daniel; Tweed, Douglas B; Akerman, Colin J

    2016-11-08

    The brain processes information through multiple layers of neurons. This deep architecture is representationally powerful, but complicates learning because it is difficult to identify the responsible neurons when a mistake is made. In machine learning, the backpropagation algorithm assigns blame by multiplying error signals with all the synaptic weights on each neuron's axon and further downstream. However, this involves a precise, symmetric backward connectivity pattern, which is thought to be impossible in the brain. Here we demonstrate that this strong architectural constraint is not required for effective error propagation. We present a surprisingly simple mechanism that assigns blame by multiplying errors by even random synaptic weights. This mechanism can transmit teaching signals across multiple layers of neurons and performs as effectively as backpropagation on a variety of tasks. Our results help reopen questions about how the brain could use error signals and dispel long-held assumptions about algorithmic constraints on learning.

  10. Transition metal partially supported graphene: Magnetism and oscillatory electrostatic potentials

    DOE PAGES

    Liu, Xiaojie; Wang, Cai-Zhuang

    2017-08-07

    Using first-principles calculations here, we show that Mn and Cr layers under graphene exhibit almost zero magnetic moment due to anti-ferromagnetic order, while ferromagnetic coupling in Fe, Co, and Ni leads to large magnetic moment. The transition metal partially supported graphene, with a mixture of supported and pristine areas, exhibits an oscillatory electrostatic potential, thus alternating the electric field across the supported and pristine areas. Such an effect can be utilized to control mass transport and nanostructure self-organization on graphene at the atomic level.

  11. Transition metal partially supported graphene: Magnetism and oscillatory electrostatic potentials

    NASA Astrophysics Data System (ADS)

    Liu, Xiaojie; Wang, Cai-Zhuang

    2017-08-01

    Using first-principles calculations, we show that Mn and Cr layers under graphene exhibit almost zero magnetic moment due to anti-ferromagnetic order, while ferromagnetic coupling in Fe, Co, and Ni leads to large magnetic moment. Transition metal partially supported graphene, with a mixture of supported and pristine areas, exhibits an oscillatory electrostatic potential, thus alternating the electric field across the supported and pristine areas. Such an effect can be utilized to control mass transport and nanostructure self-organization on graphene at the atomic level.

  12. Posture interacts with arm weight support to modulate corticomotor excitability to the upper limb.

    PubMed

    Runnalls, Keith D; Anson, Greg; Byblow, Winston D

    2017-01-01

    The use of arm weight support (WS) to optimize movement quality may be an avenue for improved upper limb stroke rehabilitation; however, the underlying neurophysiological effects of WS are not well understood. Rehabilitation exercises may be performed when sitting or standing, but the interaction of posture with WS has not been examined until now. We explored the effect of posture with WS on corticomotor excitability (CME) in healthy adults. Thirteen participants performed static shoulder abduction in two postures (sitting and standing) at three levels of WS (0, 45, and 90 % of full support). Transcranial magnetic stimulation of primary motor cortex was used to elicit motor-evoked potentials (MEPs) in eight upper limb muscles. Stimulus-response (SR) curves were fitted to the MEP data using nonlinear regression. Whole-body posture interacted with WS to influence tonic activity and CME in all muscles examined. SR curve parameters revealed greater CME when standing compared to sitting for upper arm muscles, but lower CME to the shoulder, forearm, and hand. Distal to the shoulder, tonic activity and CME were modulated independent of any explicit differences in task requirements. Overall, these results support a model of integrated upper limb control influenced by whole-body posture and WS. These findings have implications for the application of WS in settings such as upper limb rehabilitation after stroke.

  13. Which worksite supports for healthy weight do employees use?

    PubMed Central

    Tabak, Rachel G.; Hipp, J. Aaron; Marx, Christine M.; Yang, Lin; Brownson, Ross C.

    2016-01-01

    This paper explores factors associated with employee use of available supports for improving nutrition and activity behaviors. A cross-sectional telephone-survey assessed presence and use of available program, facility, and policy supports. Logistic regression was used to explore associations between job characteristics (e.g., supervising others) and use of available supports, adjusting for demographic characteristics. After adjustment, most supports were associated with at least one job-related factor. Participants supervising others were more likely to utilize eight supports including personal services for fitness, indoor exercise and shower facilities, and flextime for physical activity. The programs and facilities associated with the most factors were health fairs (e.g., increased likelihood with increased hours worked/week) and indoor exercise and shower facilities (e.g., increased likelihood with increased flexibility at work), respectively. Policies were associated with fewer factors. Since use of many programs and facilities differed based on job-related factors, employers might target supports based on job-related factors. PMID:26924850

  14. Adaptive smoothing of multi-shell diffusion weighted magnetic resonance data by msPOAS

    PubMed Central

    Becker, S.M.A.; Tabelow, K.; Mohammadi, S.; Weiskopf, N.; Polzehl, J.

    2014-01-01

    We present a novel multi-shell position-orientation adaptive smoothing (msPOAS) method for diffusion weighted magnetic resonance data. Smoothing in voxel and diffusion gradient space is embedded in an iterative adaptive multiscale approach. The adaptive character avoids blurring of the inherent structures and preserves discontinuities. The simultaneous treatment of all q-shells improves the stability compared to single-shell approaches such as the original POAS method. The msPOAS implementation simplifies and speeds up calculations, compared to POAS, facilitating its practical application. Simulations and heuristics support the face validity of the technique and its rigorousness. The characteristics of msPOAS were evaluated on single and multi-shell diffusion data of the human brain. Significant reduction in noise while preserving the fine structure was demonstrated for diffusion weighted images, standard DTI analysis and advanced diffusion models such as NODDI. MsPOAS effectively improves the poor signal-to-noise ratio in highly diffusion weighted multi-shell diffusion data, which is required by recent advanced diffusion micro-structure models. We demonstrate the superiority of the new method compared to other advanced denoising methods. PMID:24680711

  15. [Effect of vibration caused by time-varying magnetic fields on diffusion-weighted MRI].

    PubMed

    Ogura, Akio; Maeda, Fumie; Miyai, Akira; Hayashi, Kohji; Hongoh, Takaharu

    2006-04-20

    Diffusion-weighted images (DWIs) with high b-factor in the body are often used to detect and diagnose cancer at MRI. The echo planar imaging (EPI) sequence and high motion probing gradient pulse are used at diffusion weighted imaging, causing high table vibration. The purpose of this study was to assess whether the diffusion signal and apparent diffusion coefficient (ADC) values are influenced by this vibration because of time-varying magnetic fields. Two DWIs were compared. In one, phantoms were fixed on the MRI unit's table transmitting the vibration. In the other, phantoms were supported in air, in the absence of vibration. The phantoms called "solution phantoms" were made from agarose of a particular density. The phantoms called "jelly phantoms" were made from agarose that was heated. The diffusion signal and ADC value of each image were compared. The results showed that the signal of DWI units using the solution phantom was not affected by vibration. However, the signal of DWI and ADC were increased in the low-density jelly phantom as a result of vibration, causing the jelly phantom to vibrate. The DWIs of vibrating regions such as the breast maybe be subject to error. A countermeasure seems to be to support the region adequately.

  16. Polymer- and dendrimer-coated magnetic nanoparticles as versatile supports for catalysts, scavengers, and reagents.

    PubMed

    Kainz, Quirin M; Reiser, Oliver

    2014-02-18

    magnetic supports in different solvents, we can introduce dendrimers and polymers on Co/C and Fe/C platforms by various synthetic strategies. While dendrimers have the advantage of being able to array all functional groups on the surface, polymers need fewer synthetic steps and higher molecular weight analogues are easily accessible. We present the application of these promising hybrid materials for the extraction of analytes or contaminates from complex aqueous solutions (e.g. waste water treatments or blood analytics), for metal-, organo-, and biocatalysis, and in organic synthesis. In addition, we describe advanced concepts like magnetic protecting groups, a multistep synthesis solely applying magnetic reagents and scavengers, and thermoresponsive self-separating magnetic catalysts. We also discuss the first examples of the use of magnetic scaffolds manipulated by external magnetic fields in flow reactors on the laboratory scale. These hold promise for future applications of magnetic hybrid materials in continuous flow or highly parallelized syntheses with rapid magnetic separation of the applied resins.

  17. A Design Library of Magnet Support - a Proposal -

    SciTech Connect

    Ruland, Robert E.; /SLAC

    2005-08-16

    Although the ideal and universal support system has not been invented yet, there are many implementations which fulfill most of alignment's requirements. However, inventing a new support system seems to represent the last design challenge, why would we otherwise witness so many new attempts. Already Plato reminded his scholars that one should learn from the past. Unfortunately, learning from previous designs and implementations doesn't seem to carry much attraction. Or it is that we, the customers, are not doing our job by letting the design engineer know what we would like to see done, what we think works, and what is already there. This contribution is an initiative to create a reference for support systems which exist in our laboratories and we know do work. Such an undertaking will require everybody's active support and feedback. I already have to thank my peers at many laboratories who helped me put together this first draft. Only if a more or less complete library of existing designs can be compiled with easy access to drawings can we then hope that the support system design competition looses its challenge. As alignment tolerances get ever tighter, the interplay of alignment with mechanical engineering becomes ever more important. In fact, accelerator alignment has advanced so far that mechanical uncertainties now exceed observational uncertainties. Of the mechanical issues bearing upon alignment, one of the most crucial is the magnet supports; these must provide both stability and a fineness of motion substantially exceeding the final alignment tolerances. Magnet supports are the interface that allows mechanical mounting of components and their subsequent alignment to a nominal position in three-dimensional space. Supports thus provide two functions: that of a spacer to bring the component close to its ideal position, and that of a fine motion system to enable the surveyor to move the component to its ideal location within the required tolerance. It is

  18. Use of magnetic compression to support turbine engine rotors

    NASA Astrophysics Data System (ADS)

    Pomfret, Chris J.

    1994-02-01

    Ever since the advent of gas turbine engines, their rotating disks have been designed with sufficient size and weight to withstand the centrifugal forces generated when the engine is operating. Unfortunately, this requirement has always been a life and performance limiting feature of gas turbine engines and, as manufacturers strive to meet operator demands for more performance without increasing weight, the need for innovative technology has become more important. This has prompted engineers to consider a fundamental and radical breakaway from the traditional design of turbine and compressor disks which have been in use since the first jet engine was flown 50 years ago. Magnetic compression aims to counteract, by direct opposition rather than restraint, the centrifugal forces generated within the engine. A magnetic coupling is created between a rotating disk and a stationary superconducting coil to create a massive inwardly-directed magnetic force. With the centrifugal forces opposed by an equal and opposite magnetic force, the large heavy disks could be dispensed with and replaced with a torque tube to hold the blades. The proof of this concept has been demonstrated and the thermal management of such a system studied in detail; this aspect, especially in the hot end of a gas turbine engine, remains a stiff but not impossible challenge. The potential payoffs in both military and commercial aviation and in the power generation industry are sufficient to warrant further serious studies for its application and optimization.

  19. Use of magnetic compression to support turbine engine rotors

    NASA Technical Reports Server (NTRS)

    Pomfret, Chris J.

    1994-01-01

    Ever since the advent of gas turbine engines, their rotating disks have been designed with sufficient size and weight to withstand the centrifugal forces generated when the engine is operating. Unfortunately, this requirement has always been a life and performance limiting feature of gas turbine engines and, as manufacturers strive to meet operator demands for more performance without increasing weight, the need for innovative technology has become more important. This has prompted engineers to consider a fundamental and radical breakaway from the traditional design of turbine and compressor disks which have been in use since the first jet engine was flown 50 years ago. Magnetic compression aims to counteract, by direct opposition rather than restraint, the centrifugal forces generated within the engine. A magnetic coupling is created between a rotating disk and a stationary superconducting coil to create a massive inwardly-directed magnetic force. With the centrifugal forces opposed by an equal and opposite magnetic force, the large heavy disks could be dispensed with and replaced with a torque tube to hold the blades. The proof of this concept has been demonstrated and the thermal management of such a system studied in detail; this aspect, especially in the hot end of a gas turbine engine, remains a stiff but not impossible challenge. The potential payoffs in both military and commercial aviation and in the power generation industry are sufficient to warrant further serious studies for its application and optimization.

  20. Vibration study of the APS storage ring 0. 8 meter quadrupole magnet/magnet support assembly

    SciTech Connect

    Jendrzejczyk, J.A.; Wambsganss, M.W.; Smith, R.K.

    1991-06-01

    The objectives of this study are as follows: Determine the vibration characteristics (frequency, damping, and mode shapes) of the magnet on prototypic supports (the actual mounting system used to mount the magnet on the girder). Measure system response to ambient floor motion. Measure the effect of various modifications to determine if the magnet response can be modified to minimize unwanted response characteristics. Modifications investigated include support schemes, increasing system damping, and increasing mechanical rigidity. Measure system response to coolant flow. Determine vibrational characteristics of a large concrete block placed on a concrete floor, including response to ambient floor motions.

  1. Combined magnetic resonance imaging approach for the assessment of in vivo knee joint kinematics under full weight-bearing conditions.

    PubMed

    Al Hares, Ghaith; Eschweiler, Jörg; Radermacher, Klaus

    2015-06-01

    The development of detailed and specific knowledge on the biomechanical behavior of loaded knee structures has received increased attention in recent years. Stress magnetic resonance imaging techniques have been introduced in previous work to study knee kinematics under load conditions. Previous studies captured the knee movement either in atypical loading supine positions, or in upright positions with help of inclined supporting backrests being insufficient for movement capture under full-body weight-bearing conditions. In this work, we used a combined magnetic resonance imaging approach for measurement and assessment in knee kinematics under full-body weight-bearing in single legged stance. The proposed method is based on registration of high-resolution static magnetic resonance imaging data acquired in supine position with low-resolution data, quasi-static upright-magnetic resonance imaging data acquired in loaded positions for different degrees of knee flexion. The proposed method was applied for the measurement of tibiofemoral kinematics in 10 healthy volunteers. The combined magnetic resonance imaging approach allows the non-invasive measurement of knee kinematics in single legged stance and under physiological loading conditions. We believe that this method can provide enhanced understanding of the loaded knee kinematics. © IMechE 2015.

  2. Magnetic properties of supported metal atoms and clusters

    NASA Astrophysics Data System (ADS)

    Martins, Michael; Wurth, Wilfried

    2016-12-01

    Clusters are small systems ranging from a few atoms up to several thousand atoms. They are of high interest in basic research, but also for applications due to their specific electronic, magnetic or chemical properties depending on size and composition. For small clusters, quantum size effects play an important role and specific material properties might be tailored by choosing a special size or composition of the cluster. Here, we review the magnetic properties of adatoms and supported small mass-selected transition-metal clusters in the few-atom limit investigated by x-ray magnetic circular dichroism spectroscopy in the soft x-ray regime. The influence of cluster size, composition, the cluster-surface and intra-cluster interaction on the spin and orbital magnetic moments will be discussed.

  3. Magnetic nanoparticles supported ionic liquids improve firefly luciferase properties.

    PubMed

    Noori, Ali Reza; Hosseinkhani, Saman; Ghiasi, Parisa; Akbari, Jafar; Heydari, Akbar

    2014-03-01

    Ionic liquids as neoteric solvents, microwave irradiation, and alternative energy source are becoming as a solvent for many enzymatic reactions. We recently showed that the incubation of firefly luciferase from Photinus pyralis with various ionic liquids increased the activity and stability of luciferase. Magnetic nanoparticles supported ionic liquids have been obtained by covalent bonding of ionic liquids-silane on magnetic silica nanoparticles. In the present study, the effects of [γ-Fe2O3@SiO2][BMImCl] and [γ-Fe2O3@SiO2][BMImI] were investigated on the structural properties and function of luciferase using circular dichroism, fluorescence spectroscopy, and bioluminescence assay. Enzyme activity and structural stability increased in the presence of magnetic nanoparticles supported ionic liquids. Furthermore, the effect of ingredients which were used was not considerable on K(m) value of luciferase for adenosine-5'-triphosphate and also K(m) value for luciferin.

  4. A low molecular weight folate receptor targeted contrast agent for magnetic resonance tumor imaging.

    PubMed

    Kalber, Tammy L; Kamaly, Nazila; So, Po-Wah; Pugh, John A; Bunch, Josephine; McLeod, Cameron W; Jorgensen, Michael R; Miller, Andrew D; Bell, Jimmy D

    2011-08-01

    This study aims to develop a low molecular weight folate receptor (FR) contrast agent for MR tumor imaging. Gadolinium-tetraazacyclododecane tetraacetic acid (Gd.DOTA) was conjugated to folic acid to create Gd.DOTA.Folate. The efficacy of Gd.DOTA.Folate to bind FR was evaluated in vitro by inductively coupled mass spectrometry (ICP-MS) and in vivo by magnetic resonance imaging (MRI) tumor enhancement over 14 h, utilizing an overexpressing α-FR cell line (IGROV-1), compared to an α-FR-negative cell line (OVCAR-3). Gd.DOTA.Folate localization ex vivo was verified by laser ablation ICP-MS. ICP-MS confirmed Gd.DOTA.Folate uptake by IGROV-1 cells and competitive binding with free folic acid inhibited binding. IGROV-1 tumors showed an increase in R (1) at 2 h, which increased significantly over 14 h post-Gd.DOTA.Folate with clear enhancement on MR images. This was not observed in controls. These data support the use of FR-targeted small molecular weight MRI contrast agents for tumor imaging in vivo.

  5. Effect of hospital nutrition support on growth velocity and nutritional status of low birth weight infants.

    PubMed

    Azzeh, Firas S; Alazzeh, Awfa Y; Dabbour, Ibrahim R; Jazar, Abdelelah S; Obeidat, Ahmed A

    2014-10-01

    Infants with low birth weights are provided with hospital nutrition support to enhance their survivability and body weights. However, different hospitals have different nutrition support formulas. Therefore, the effectiveness of these nutrition support formulas should be investigated. To assess the effect of hospital nutrition support on growth velocity and nutritional status of low birth weight infants at Al-Noor hospital, Saudi Arabia. A cross-sectional study was conducted between October, 2010 and December, 2012. Three hundred newborns were recruited from Al-Noor Hospital in Makkah city, Saudi Arabia. Infants were selected according to their birth weights and were divided equally into three groups; (i) Low Birth Weight (LBW) infants (1501- 2500 g birth weight), (ii) Very Low Birth Weight (VLBW) infants (1001-1500 g birth weight) and (iii) Extremely Low Birth Weight (ELBW) infants (< 1000 g birth weight). Data were collected at birth and at discharged. Infants' weights were recorded and growth velocity was calculated. Some biochemical tests and mineral levels were measured. Body mass index values of VLBW and ELBW groups were lower (p < 0.05) than LBW group. The growth velocity of infants in all groups ranged between 8.7 to 10.2 g/kg/d with no differences (p > 0.05) were observed among groups. Serum calcium, phosphorus and potassium levels at discharge were higher (p < 0.05) than that at birth for ELBW and VLBW groups; while sodium level decreased in ELBW group to be within normal ranges. Albumin level was improved (p < 0.05) in ELBW group. Health care management for low birth weight infants in Al-Noor Hospital was not sufficient to achieve normal growth rate for low birth weight infants, while biochemical indicators were remarkably improved in all groups. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  6. Design study for a magnetically supported reaction wheel

    NASA Technical Reports Server (NTRS)

    Stocking, G.; Dendy, J.; Sabnis, A.

    1974-01-01

    Results are described of a study program in which the characteristics of a magnetically supported reaction wheel are defined. Tradeoff analyses are presented for the principal components, which are then combined in several reaction wheel design concepts. A preliminary layout of the preferred configuration is presented along with calculated design and performance parameters. Recommendations are made for a prototype development program.

  7. The role of nurse support within an Internet-delivered weight management intervention: A qualitative study.

    PubMed

    Renouf, Sarah; Bradbury, Katherine; Yardley, Lucy; Little, Paul

    2015-01-01

    This qualitative study explored patients' experiences of nurse support for an Internet-delivered weight management intervention. Eighteen patients who had received either basic or regular nurse support (three or seven contacts, respectively) for the Internet intervention were interviewed. The data were analysed using thematic analysis. The findings suggest that more regular support for Internet interventions may have the potential to inhibit the development of autonomous motivation for weight loss, which might lead to problems in sustaining losses after support ends. Further research is now needed to confirm whether motivation is influenced by frequency of nurse support in Internet interventions in order to inform the development of optimal support which promotes sustained weight loss.

  8. Strategies to Address Weight-Based Victimization: Youths' Preferred Support Interventions from Classmates, Teachers, and Parents

    ERIC Educational Resources Information Center

    Puhl, Rebecca M.; Peterson, Jamie Lee; Luedicke, Joerg

    2013-01-01

    Weight-Based Victimization is a frequent experience for adolescents who are overweight or obese, and is associated with numerous psychosocial and physical consequences for those who are targets of victimization. Assessing targets' preferences for different types of support and intervention has been absent in the context of weight-based…

  9. Combating Weight-Based Bullying in Schools: Is There Public Support for the Use of Litigation?

    ERIC Educational Resources Information Center

    Puhl, Rebecca; Luedicke, Joerg; King, Kelly M.

    2015-01-01

    Background: Bullying litigation is an emerging area of law that has increased in response to serious cases of bullying at school. Weight-based bullying is prevalent at school, but no research has examined the use of litigation to address this problem. We assessed public support for litigation approaches to address weight-based bullying at school,…

  10. Combating Weight-Based Bullying in Schools: Is There Public Support for the Use of Litigation?

    ERIC Educational Resources Information Center

    Puhl, Rebecca; Luedicke, Joerg; King, Kelly M.

    2015-01-01

    Background: Bullying litigation is an emerging area of law that has increased in response to serious cases of bullying at school. Weight-based bullying is prevalent at school, but no research has examined the use of litigation to address this problem. We assessed public support for litigation approaches to address weight-based bullying at school,…

  11. Effects of Peer Support and Therapist Contact on Long-Term Weight Loss.

    ERIC Educational Resources Information Center

    Perri, Michael G.; And Others

    1987-01-01

    Evaluated effectiveness of posttreatment programs to enhance weight loss maintenance. Obese clients (N=85) participated in either behavior therapy, behavior therapy and peer-support, or behavior therapy and therapist-contact programs. At 7-month follow-up, therapist-contact program showed significantly greater weight loss maintenance than did…

  12. Effects of Peer Support and Therapist Contact on Long-Term Weight Loss.

    ERIC Educational Resources Information Center

    Perri, Michael G.; And Others

    1987-01-01

    Evaluated effectiveness of posttreatment programs to enhance weight loss maintenance. Obese clients (N=85) participated in either behavior therapy, behavior therapy and peer-support, or behavior therapy and therapist-contact programs. At 7-month follow-up, therapist-contact program showed significantly greater weight loss maintenance than did…

  13. Effects of social support and spirituality on weight loss for rural African-American women.

    PubMed

    Nam, Sanggon

    2013-01-01

    Obesity continues to be an increasing health problem among African-American women. A 10-week weight-loss intervention program designed to address the problem in these women. Two different interventions (spiritually based and nonspiritually based) were tested, and both utilized a pre-test, posttest design On the basis of theories of social support, it was expected that participation in the intervention would produce a significant reduction in weight. In addition, the spiritual-based weight-loss program was hypothesized to produce greater weight reduction than the standard health (non-spiritual) program. The results demonstrated that the average weight and BMI of all participants in either a spiritually-based or a nonspiritually-based program were lower at the completion of the intervention program. In addition, the average weight and BMI loss for the spiritual group was significantly greater than the average weight and BMI loss for the non-spiritual group.

  14. Modelling and control of a rotor supported by magnetic bearings

    NASA Technical Reports Server (NTRS)

    Gurumoorthy, R.; Pradeep, A. K.

    1994-01-01

    In this paper we develop a dynamical model of a rotor and the active magnetic bearings used to support the rotor. We use this model to develop a stable state feedback control of the magnetic bearing system. We present the development of a rigid body model of the rotor, utilizing both Rotation Matrices (Euler Angles) and Euler Parameters (Quaternions). In the latter half of the paper we develop a stable state feedback control of the actively controlled magnetic bearing to control the rotor position under inbalances. The control law developed takes into account the variation of the model with rotational speed. We show stability over the whole operating range of speeds for the magnetic bearing system. Simulation results are presented to demonstrate the closed loop system performance. We develop the model of the magnetic bearing, and present two schemes for the excitation of the poles of the actively controlled magnetic bearing. We also present a scheme for averaging multiple sensor measurements and splitting the actuation forces amongst redundant actuators.

  15. Periodic weight support effects on rat soleus fibers after hindlimb suspension

    NASA Technical Reports Server (NTRS)

    Hauschka, Edward O.; Roy, Roland R.; Edgerton, V. Reggie

    1988-01-01

    The morphological and histochemical properties of rat soleus muscles were investigated following one week of hindlimb suspension. Short-duration daily weight support activity is shown to ameliorate, but not prevent, soleus atrophy induced by hindlimb suspension. The results indicate that fiber cross-sectional area is more responsive to periodic weight support in dark than light ATPas fibers, and that muscle fiber atrophy need not be associated with a loss in succinate dehydrogenase activity.

  16. Assessment of cerebral venous sinus thrombosis using T2*-weighted gradient echo magnetic resonance imaging sequences

    PubMed Central

    Bidar, Fatemeh; Faeghi, Fariborz; Ghorbani, Askar

    2016-01-01

    Background: The purpose of this study is to demonstrate the advantages of gradient echo (GRE) sequences in the detection and characterization of cerebral venous sinus thrombosis compared to conventional magnetic resonance sequences. Methods: A total of 17 patients with cerebral venous thrombosis (CVT) were evaluated using different magnetic resonance imaging (MRI) sequences. The MRI sequences included T1-weighted spin echo (SE) imaging, T*2-weighted turbo SE (TSE), fluid attenuated inversion recovery (FLAIR), T*2-weighted conventional GRE, and diffusion weighted imaging (DWI). MR venography (MRV) images were obtained as the golden standard. Results: Venous sinus thrombosis was best detectable in T*2-weighted conventional GRE sequences in all patients except in one case. Venous thrombosis was undetectable in DWI. T*2-weighted GRE sequences were superior to T*2-weighted TSE, T1-weighted SE, and FLAIR. Enhanced MRV was successful in displaying the location of thrombosis. Conclusion: T*2-weighted conventional GRE sequences are probably the best method for the assessment of cerebral venous sinus thrombosis. The mentioned method is non-invasive; therefore, it can be employed in the clinical evaluation of cerebral venous sinus thrombosis. PMID:27326365

  17. MIT-Skywalker: considerations on the Design of a Body Weight Support System.

    PubMed

    Gonçalves, Rogério Sales; Krebs, Hermano Igo

    2017-09-06

    To provide body weight support during walking and balance training, one can employ two distinct embodiments: support through a harness hanging from an overhead system or support through a saddle/seat type. This paper presents a comparison of these two approaches. Ultimately, this comparison determined our selection of the body weight support system employed in the MIT-Skywalker, a robotic device developed for the rehabilitation/habilitation of gait and balance after a neurological injury. Here we will summarize our results with eight healthy subjects walking on the treadmill without any support, with 30% unloading supported by a harness hanging from an overhead system, and with a saddle/seat-like support system. We compared the center of mass as well as vertical and mediolateral trunk displacements across different walking speeds and support. The bicycle/saddle system had the highest values for the mediolateral inclination, while the overhead harness body weight support showed the lowest values at all speeds. The differences were statistically significant. We selected the bicycle/saddle system for the MIT-Skywalker. It allows faster don-and-doff, better centers the patient to the split treadmill, and allows all forms of training. The overhead harness body weight support might be adequate for rhythmic walking training but limits any potential for balance training.

  18. Vibration and Control of Flexible Rotor Supported by Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Nonami, Kenzou

    1988-01-01

    Active vibration control of flexible rotors supported by magnetic bearings is discussed. Using a finite-element method for a mathematical model of the flexible rotor, the eigenvalue problem is formulated taking into account the interaction between a mechanical system of the flexible rotor and an electrical system of the magnetic bearings and the controller. However, for the sake of simplicity, gyroscopic effects are disregarded. It is possible to adapt this formulation to a general flexible rotor-magnetic bearing system. Controllability with and without collocation sensors and actuators located at the same distance along the rotor axis is discussed for the higher order flexible modes of the test rig. In conclusion, it is proposed that it is necessary to add new active control loops for the higher flexible modes even in the case of collocation. Then it is possible to stabilize for the case of uncollocation by means of this method.

  19. Digital control of magnetic bearings supporting a multimass flexible rotor

    NASA Technical Reports Server (NTRS)

    Keith, F. J.; Williams, R. D.; Allaire, P. E.; Schafer, R. M.

    1993-01-01

    The characteristics of magnetic bearings used to support a three mass flexible rotor operated at speeds up to 14,000 RPM are discussed. The magnetic components of the bearing are of a type reported in the literature previously, but the earlier analog controls were replaced by digital ones. Analog-to-digital and digital-to-analog converters and digital control software were installed in an AT&T PC. This PC-based digital controller was used to operate one of the magnetic bearings on the test rig. Basic proportional-derivative control was applied to the bearings, and the bearing stiffness and damping characteristics were evaluated. Particular attention is paid to the frequency dependent behavior of the stiffness and damping properties, and comparisons are made between the actual controllers and ideal proportional-derivative control.

  20. Prototype ventricular assist device supported on magnetic bearings

    SciTech Connect

    Allaire, P.E.; Maslen, E.H.; Kim, H.C.; Olsen, D.B.; Bearnson, G.D.

    1995-12-31

    Mechanical artificial hearts are now expected to be used as assist or total replacements for failing human hearts, if a reliable, anatomically appropriate design is developed. Initially, ventricular assist or total replacement devices were pulsatile air driven units containing a flexing polymeric diaphragm and two valves for each ventricle. Many reliability problems were encountered. Recently, attention has been focused on axial or centrifugal continuous flow blood pumps. Magnetic bearings employed in such devices offer the advantages of no required lubrication and large operating clearances. This paper describes a prototype continuous flow pump supported in magnetic bearings. The pump performance was measured in a simulated adult human circulation system. It delivered 6 liters/min of flow at 100 mm Hg differential head operating at 2,400 rpm in water. The pump is totally magnetically supported in four magnetic bearings - two radial and two thrust. The geometry and other properties of the bearings are described. Bearing parameters such as load capacity, current gains, and open loop stiffness are discussed. Bearing coil currents were measured during operation in air and water. The rotor was operated in various orientations to determine the actuator current gains. These values were then used to estimate the radial and thrust forces acting on the rotor in both air and water.

  1. Magnetic bearing development for support of satellite flywheels

    NASA Astrophysics Data System (ADS)

    Palazzolo, Alan; Li, Mu; Kenny, Andrew; Lei, Shuliang; Havelka, Danny; Kascak, Albert

    1998-01-01

    The use of magnetic bearings (MB) for support of space based flywheels can provide significant improvement in efficiency due to reduction in drag torque. A NASA supported program directed through the Texas A&M Center for Space Power has been formed to advance the technology of MB's for satellite flywheel applications. The five areas of the program are: (a) Magnetic Field Simulation, (b) MB controller Development, (c) Electromechanical Rotordynamics Modeling, (d) Testing and (e) Technology Exchange. Planned innovations in these tasks include eddy current drag torque and power loss determination including moving conductor effects, digital (DSP) based control for high speed operation, MATLAB-based coupled flexible rotor/controller/actuator electromechanical model with fuzzy logic nonlinear control, and ultra high speed>100 krpm measurement of drag torque. The paper examines these areas and provides an overview of the project.

  2. Superconducting magnetic energy storage apparatus structural support system

    DOEpatents

    Withers, Gregory J.; Meier, Stephen W.; Walter, Robert J.; Child, Michael D.; DeGraaf, Douglas W.

    1992-01-01

    A superconducting magnetic energy storage apparatus comprising a cylindrical superconducting coil; a cylindrical coil containment vessel enclosing the coil and adapted to hold a liquid, such as liquefied helium; and a cylindrical vacuum vessel enclosing the coil containment vessel and located in a restraining structure having inner and outer circumferential walls and a floor; the apparatus being provided with horizontal compression members between (1) the coil and the coil containment vessel and (2) between the coil containment vessel and the vacuum vessel, compression bearing members between the vacuum vessel and the restraining structure inner and outer walls, vertical support members (1) between the coil bottom and the coil containment vessel bottom and (2) between the coil containment vessel bottom and the vacuum vessel bottom, and external supports between the vacuum vessel bottom and the restraining structure floor, whereby the loads developed by thermal and magnetic energy changes in the apparatus can be accommodated and the structural integrity of the apparatus be maintained.

  3. Apparatus having reduced mechanical forces for supporting high magnetic fields

    DOEpatents

    Prueitt, Melvin L.; Mueller, Fred M.; Smith, James L.

    1991-01-01

    The present invention identifies several configurations of conducting elements capable of supporting extremely high magnetic fields suitable for plasma confinement, wherein forces experienced by the conducting elements are significantly reduced over those which are present as a result of the generation of such high fields by conventional techniques. It is anticipated that the use of superconducting materials will both permit the attainment of such high fields and further permit such fields to be generated with vastly improved efficiency.

  4. A novel body weight support system extension: initial concept and simulation study.

    PubMed

    Pennycott, Andrew; Vallery, Heike; Wyss, Dario; Spindler, Markus; Dewarrat, Antoine; Riener, Robert

    2013-06-01

    Body weight supported treadmill training is an approach to gait rehabilitation following a stroke or spinal cord injury. Although lateral control of balance is an important aspect of walking, many of the currently available body weight support systems have a fixed pulley configuration which can lead to lateral forces being developed in the supporting cables, interfering with the lateral balance task. In this paper, a novel extension for body weight support systems, used for treadmill walking, is presented which features a system of pulleys and trolleys. A model is developed for the device along with a basic feedback controller in order to enable simulation of the concept. The lateral forces induced by the novel system are greatly reduced in comparison to a fixed pulley system. This device has applications in balance training within gait rehabilitation programs.

  5. Effects of obesity on weight-bearing versus weight-supported exercise testing in patients with COPD.

    PubMed

    Maatman, Robbert C; Spruit, Martijn A; van Melick, Paula P; Peeters, Jos P I; Rutten, Erica P A; Vanfleteren, Lowie E G W; Wouters, Emiel F M; Franssen, Frits M E

    2016-04-01

    Obesity is associated with increased dyspnoea and reduced health status in patients with chronic obstructive pulmonary disease (COPD). Studies on the effects of obesity on exercise capacity showed divergent results. The objective of this study is to investigate the impact of obesity on weight-bearing versus weight-supported exercise tolerance in obese and normal weight patients, matched for age, gender and degree of airflow limitation. Retrospective analyses of data obtained during pre-pulmonary rehabilitation assessment in 108 obese COPD patients (OB) (age: 61.2 ± 5.3y, FEV1 : 43.2 ± 7.4%, BMI: 34.1 ± 3.9 kg/m(2) ,) and 108 age and FEV1 -matched normal weight COPD patients (NW) (age: 61.7 ± 3.6y, FEV1 : 41.5 ± 8.4%, BMI: 22.9 ± 1.2 kg/m(2) ,). Cardiopulmonary exercise test (CPET) and 6 min walk test (6MWT) were performed, Borg scores for dyspnoea and leg fatigue were recorded, before and after the tests. Six-minute walk distance differed between OB (398 ± 107 m) and NW patients (446 ± 109 m, P < 0.05), while peak cycling exercise load was comparable (OB: 75 ± 29 W, NW: 70 ± 25 W, ns). Dyspnoea (OB 3.2 ± 2.0 vs NW 3.1 ± 1.7, ns) and leg fatigue (OB 2.4 ± 2.3 vs NW 1.9 ± 1.7, ns) were not significantly different in OB compared with NW after 6MWT, or after CPET (dyspnoea: OB 5.1 ± 2.4 vs NW 5.4 ± 2.2, ns; leg fatigue: OB 4.0 ± 2.3 vs NW 4.0 ± 2.7, ns). In contrast to weight-supported exercise, obesity has a negative impact on weight-bearing exercise capacity, despite comparable exercise-related symptoms. The results of this study enhance the understanding of the impact of obesity on physical performance in COPD. © 2015 Asian Pacific Society of Respirology.

  6. Weight gain and metabolic complications in preterm infants with nutritional support.

    PubMed

    Monroy-Torres, Rebeca; Macías, Alejandro E; Ponce-de-León, Samuel; Barbosa-Sabanero, Gloria

    2011-01-01

    To analyze the weight gain and to describe the metabolic complications in preterm newborns with nutritional support (NS) and to describe nutritional practices in the first month of hospitalization for 52 preterm newborns. Descriptive and prospective study of preterm infants (30-36 gestational weeks), with birth weight > 1 kg, hospital stay > 12 days, without respiratory support or complications, conducted at a public hospital in Leon, Guanajuato, Mexico from January to November 2006. Weight, serum glucose, insulin, cholesterol, triglycerides, gamma-glutamyltransferase, creatinine, urea nitrogen, type of NS (parenteral PN, enteral EN, mixed MN), energy content, and macronutrient intake were measured weekly. To obtain representative data, nutritional practices were not altered by the study protocol. One way ANOVA and Wilcoxon tests were used in data analyses. Overall, 52 newborns were included, averaging 33 gestational weeks and 1,590 g of weight. The NS was started by the fourth day on average. Parenteral nutrition was the most frequent NS during the first 2 weeks (75%). Energy and macronutrient supply was 50% less than the recommended. Weight gain ranged from -100 to 130 g/week. Parenteral nutrition showed better weekly weight gain, followed by EN. The metabolic complication rate per person-day was greater for MN (0.56), than for EN (0.16) or PN (0.09). Routine surveillance of weight and metabolic complications was deficient. Late onset of NS, insufficient energy supply, and deficient surveillance were obstacles to weight gain and to prevent the metabolic complications in these newborns.

  7. T2-Weighted 4D Magnetic Resonance Imaging for Application in Magnetic Resonance-Guided Radiotherapy Treatment Planning.

    PubMed

    Freedman, Joshua N; Collins, David J; Bainbridge, Hannah; Rank, Christopher M; Nill, Simeon; Kachelrieß, Marc; Oelfke, Uwe; Leach, Martin O; Wetscherek, Andreas

    2017-10-01

    The aim of this study was to develop and verify a method to obtain good temporal resolution T2-weighted 4-dimensional (4D-T2w) magnetic resonance imaging (MRI) by using motion information from T1-weighted 4D (4D-T1w) MRI, to support treatment planning in MR-guided radiotherapy. Ten patients with primary non-small cell lung cancer were scanned at 1.5 T axially with a volumetric T2-weighted turbo spin echo sequence gated to exhalation and a volumetric T1-weighted stack-of-stars spoiled gradient echo sequence with golden angle spacing acquired in free breathing. From the latter, 20 respiratory phases were reconstructed using the recently developed 4D joint MoCo-HDTV algorithm based on the self-gating signal obtained from the k-space center. Motion vector fields describing the respiratory cycle were obtained by deformable image registration between the respiratory phases and projected onto the T2-weighted image volume. The resulting 4D-T2w volumes were verified against the 4D-T1w volumes: an edge-detection method was used to measure the diaphragm positions; the locations of anatomical landmarks delineated by a radiation oncologist were compared and normalized mutual information was calculated to evaluate volumetric image similarity. High-resolution 4D-T2w MRI was obtained. Respiratory motion was preserved on calculated 4D-T2w MRI, with median diaphragm positions being consistent with less than 6.6 mm (2 voxels) for all patients and less than 3.3 mm (1 voxel) for 9 of 10 patients. Geometrical positions were coherent between 4D-T1w and 4D-T2w MRI as Euclidean distances between all corresponding anatomical landmarks agreed to within 7.6 mm (Euclidean distance of 2 voxels) and were below 3.8 mm (Euclidean distance of 1 voxel) for 355 of 470 pairs of anatomical landmarks. Volumetric image similarity was commensurate between 4D-T1w and 4D-T2w MRI, as mean percentage differences in normalized mutual information (calculated over all respiratory phases and patients), between

  8. Weighted current sheets supported in normal and inverse configurations - A model for prominence observations

    NASA Technical Reports Server (NTRS)

    Demoulin, P.; Forbes, T. G.

    1992-01-01

    A technique which incorporates both photospheric and prominence magnetic field observations is used to analyze the magnetic support of solar prominences in two dimensions. The prominence is modeled by a mass-loaded current sheet which is supported against gravity by magnetic fields from a bipolar source in the photosphere and a massless line current in the corona. It is found that prominence support can be achieved in three different kinds of configurations: an arcade topology with a normal polarity; a helical topology with a normal polarity; and a helical topology with an inverse polarity. In all cases the important parameter is the variation of the horizontal component of the prominence field with height. Adding a line current external to the prominence eliminates the nonsupport problem which plagues virtually all previous prominence models with inverse polarity.

  9. Weighted current sheets supported in normal and inverse configurations - A model for prominence observations

    NASA Technical Reports Server (NTRS)

    Demoulin, P.; Forbes, T. G.

    1992-01-01

    A technique which incorporates both photospheric and prominence magnetic field observations is used to analyze the magnetic support of solar prominences in two dimensions. The prominence is modeled by a mass-loaded current sheet which is supported against gravity by magnetic fields from a bipolar source in the photosphere and a massless line current in the corona. It is found that prominence support can be achieved in three different kinds of configurations: an arcade topology with a normal polarity; a helical topology with a normal polarity; and a helical topology with an inverse polarity. In all cases the important parameter is the variation of the horizontal component of the prominence field with height. Adding a line current external to the prominence eliminates the nonsupport problem which plagues virtually all previous prominence models with inverse polarity.

  10. Clear Depiction of Inflammatory Abdominal Aortic Aneurysm with Diffusion-Weighted Magnetic Resonance Imaging

    SciTech Connect

    Orta Kilickesmez, Kadriye; Kilickesmez, Ozgur

    2010-04-15

    We report the case of an inflammatory abdominal aortic aneurysm incidentally detected clearly with diffusion-weighted magnetic resonance imaging (DW-MRI) during the examination of a patient with myelofibrosis with myeloid metaplasia that later converted to acute myeloid leukemia. DW-MRI revealed a hyperintense halo surrounding the abdominal aorta with aneurysmatic dilatation, establishing the diagnosis.

  11. Improved equilibrium reconstructions by advanced statistical weighting of the internal magnetic measurements.

    PubMed

    Murari, A; Gelfusa, M; Peluso, E; Gaudio, P; Mazon, D; Hawkes, N; Point, G; Alper, B; Eich, T

    2014-12-01

    In a Tokamak the configuration of the magnetic fields remains the key element to improve performance and to maximise the scientific exploitation of the device. On the other hand, the quality of the reconstructed fields depends crucially on the measurements available. Traditionally in the least square minimisation phase of the algorithms, used to obtain the magnetic field topology, all the diagnostics are given the same weights, a part from a corrective factor taking into account the error bars. This assumption unduly penalises complex diagnostics, such as polarimetry, which have a limited number of highly significant measurements. A completely new method to choose the weights, to be given to the internal measurements of the magnetic fields for improved equilibrium reconstructions, is presented in this paper. The approach is based on various statistical indicators applied to the residuals, the difference between the actual measurements and their estimates from the reconstructed equilibrium. The potential of the method is exemplified using the measurements of the Faraday rotation derived from JET polarimeter. The results indicate quite clearly that the weights have to be determined carefully, since the inappropriate choice can have significant repercussions on the quality of the magnetic reconstruction both in the edge and in the core. These results confirm the limitations of the assumption that all the diagnostics have to be given the same weight, irrespective of the number of measurements they provide and the region of the plasma they probe.

  12. Diagnosis of pericardial cysts using diffusion weighted magnetic resonance imaging: A case series

    PubMed Central

    2011-01-01

    Introduction Congenital pericardial cysts are benign lesions that arise from the pericardium during embryonic development. The diagnosis is based on typical imaging features, but atypical locations and signal magnetic resonance imaging sequences make it difficult to exclude other lesions. Diffusion-weighted magnetic resonance imaging is a novel method that can be used to differentiate tissues based on their restriction to proton diffusion. Its use in differentiating pericardial cysts from other pericardial lesions has not yet been described. Case presentation We present three cases (a 51-year-old Caucasian woman, a 66-year-old Caucasian woman and a 77-year-old Caucasian woman) with pericardial cysts evaluated with diffusion-weighted imaging using cardiac magnetic resonance imaging. Each lesion demonstrated a high apparent diffusion coefficient similar to that of free water. Conclusion This case series is the first attempt to investigate the utility of diffusion-weighted magnetic resonance imaging in the assessment of pericardial cysts. Diffusion-weighted imaging may be a useful noninvasive diagnostic tool for pericardial cysts when conventional imaging findings are inconclusive. PMID:21943086

  13. A smartphone-supported weight loss program: design of the ENGAGED randomized controlled trial

    PubMed Central

    2012-01-01

    Background Obesity remains a major public health challenge, demanding cost-effective and scalable weight management programs. Delivering key treatment components via mobile technology offers a potential way to reduce expensive in-person contact, thereby lowering the cost and burden of intensive weight loss programs. The ENGAGED study is a theory-guided, randomized controlled trial designed to examine the feasibility and efficacy of an abbreviated smartphone-supported weight loss program. Methods/design Ninety-six obese adults (BMI 30–39.9 kg/m2) will be randomized to one of three treatment conditions: (1) standard behavioral weight loss (STND), (2) technology-supported behavioral weight loss (TECH); or (3) self-guided behavioral weight loss (SELF). All groups will aim to achieve a 7% weight loss goal by reducing calorie and fat intake and progressively increasing moderate intensity physical activity to 175 minutes/week. STND and TECH will attend 8 group sessions and receive regular coaching calls during the first 6 months of the intervention; SELF will receive the Group Lifestyle Balance Program DVD’s and will not receive coaching calls. During months 1–6, TECH will use a specially designed smartphone application to monitor dietary intake, body weight, and objectively measured physical activity (obtained from a Blue-tooth enabled accelerometer). STND and SELF will self-monitor on paper diaries. Linear mixed modeling will be used to examine group differences on weight loss at months 3, 6, and 12. Self-monitoring adherence and diet and activity goal attainment will be tested as mediators. Discussion ENGAGED is an innovative weight loss intervention that integrates theory with emerging mobile technologies. We hypothesize that TECH, as compared to STND and SELF, will result in greater weight loss by virtue of improved behavioral adherence and goal achievement. Trial registration NCT01051713 PMID:23194256

  14. Combating weight-based bullying in schools: is there public support for the use of litigation?

    PubMed

    Puhl, Rebecca; Luedicke, Joerg; King, Kelly M

    2015-06-01

    Bullying litigation is an emerging area of law that has increased in response to serious cases of bullying at school. Weight-based bullying is prevalent at school, but no research has examined the use of litigation to address this problem. We assessed public support for litigation approaches to address weight-based bullying at school, and whether support for litigation varies according to the reason why a student is bullied. A national sample of 994 adults (49% parents) completed an online questionnaire assessing their support for litigation approaches in response to hypothetical incidents of youth bullying. As many as two thirds of participants supported litigation against schools for failing to intervene and protect students from weight-based bullying. Litigation remedies received slightly higher support in response to bullying due to race or sexual orientation compared to body weight. Participants favored litigation approaches that target schools for inadequate intervention or a bully's parents on behalf of their child's actions. Our study offers novel findings about public and parental views of litigation as a potential approach to address weight-based (and other forms of) bullying, and introduces considerations about the potential role of litigation as part of broader remedies to address youth bullying. © 2015, American School Health Association.

  15. The effect of nutritional support on weight gain of HIV-infected children with prolonged diarrhoea.

    PubMed

    Rollins, N C; van den Broeck, J; Kindra, G; Pent, M; Kasambira, T; Bennish, M L

    2007-01-01

    To examine the effect on growth and immunity of enhanced calorie and protein provision to HIV-infected children presenting with prolonged diarrhoea. A total of 169 HIV-infected children aged 6-36 months with diarrhoea for 7 days or more were randomly assigned to either standard nutrition support for children with prolonged diarrhoea or an enhanced diet started during hospitalisation and continued after discharge. The change in weight between enrolment and 8, 14 and 26 weeks and changes in plasma HIV-RNA and CD4 cell count at 8 and 26 weeks were estimated. Children receiving enhanced nutrition achieved significantly more weight gain (p < 0.001) between enrolment and 8 weeks than children on the standard diet (median increase in weight-for-age standard deviation score +1.02 vs. +0.01). After 8 weeks median weight velocity was normal and similar in both groups. The change in median CD4 count was similar in both groups. The 26-week mortality rate was high in both groups (standard support: 22%, enhanced support: 29%). Nutrition support of children with advanced HIV infection and prolonged diarrhoea resulted in significant and sustained weight gain, but did not improve CD4 counts or survival. These results support integrated nutrition interventions for HIV-infected children.

  16. A novel device for studying weight supported, quadrupedal overground locomotion in spinal cord injured rats

    PubMed Central

    Hamlin, Marvin; Traughber, Terrance; Reinkensmeyer, David J.; de Leon, Ray D.

    2015-01-01

    Background Providing weight support facilitates locomotion in spinal cord injured animals. To control weight support, robotic systems have been developed for treadmill stepping and more recently for overground walking. New Method We developed a novel device, the body weight supported ambulatory rodent trainer (i.e. BART). It has a small pneumatic cylinder that moves along a linear track above the rat. When air is supplied to the cylinder, the rats are lifted as they perform overground walking. We tested the BART device in rats that received a moderate spinal cord contusion injury and in normal rats. Locomotor training with the BART device was not performed. Results All of the rats learned to walk in the BART device. In the contused rats, significantly greater paw dragging and dorsal stepping occurred in the hindlimbs compared to normal. Providing weight support significantly raised hip position and significantly reduced locomotor deficits. Hindlimb stepping was tightly coupled to forelimb stepping but only when the contused rats stepped without weight support. Three weeks after the contused rats received a complete spinal cord transection, significantly fewer hindlimb steps were performed. Comparison with Existing Methods Relative to rodent robotic systems, the BART device is a simpler system for studying overground locomotion. The BART device lacks sophisticated control and sensing capability, but it can be assembled relatively easily and cheaply. Conclusions These findings suggest that the BART device is a useful tool for assessing quadrupedal, overground locomotion which is a more natural form of locomotion relative to treadmill locomotion. PMID:25794460

  17. Orthotic Body-Weight Support Through Underactuated Potential Energy Shaping with Contact Constraints

    PubMed Central

    Lv, Ge; Gregg, Robert D.

    2015-01-01

    Body-weight support is an effective clinical tool for gait rehabilitation after neurological impairment. Body-weight supported training systems have been developed to help patients regain mobility and confidence during walking, but conventional systems constrain the patient's treatment in clinical environments. We propose that this challenge could be addressed by virtually providing patients with body-weight support through the actuators of a powered orthosis (or exoskeleton) utilizing potential energy shaping control. However, the changing contact conditions and degrees of underactuation encountered during human walking present significant challenges to consistently matching a desired potential energy for the human in closed loop. We therefore introduce a generalized matching condition for shaping Lagrangian systems with holonomic contact constraints. By satisfying this matching condition for four phases of gait, we derive control laws to achieve virtual body-weight support through a powered knee-ankle orthosis. We demonstrate beneficial effects of virtual body-weight support in simulations of a human-like biped model, indicating the potential clinical value of this proposed control approach. PMID:26900254

  18. Orthotic Body-Weight Support Through Underactuated Potential Energy Shaping with Contact Constraints.

    PubMed

    Lv, Ge; Gregg, Robert D

    2015-12-01

    Body-weight support is an effective clinical tool for gait rehabilitation after neurological impairment. Body-weight supported training systems have been developed to help patients regain mobility and confidence during walking, but conventional systems constrain the patient's treatment in clinical environments. We propose that this challenge could be addressed by virtually providing patients with body-weight support through the actuators of a powered orthosis (or exoskeleton) utilizing potential energy shaping control. However, the changing contact conditions and degrees of underactuation encountered during human walking present significant challenges to consistently matching a desired potential energy for the human in closed loop. We therefore introduce a generalized matching condition for shaping Lagrangian systems with holonomic contact constraints. By satisfying this matching condition for four phases of gait, we derive control laws to achieve virtual body-weight support through a powered knee-ankle orthosis. We demonstrate beneficial effects of virtual body-weight support in simulations of a human-like biped model, indicating the potential clinical value of this proposed control approach.

  19. A voxel based comparative analysis using magnetization transfer imaging and T1-weighted magnetic resonance imaging in progressive supranuclear palsy

    PubMed Central

    Sandhya, Mangalore; Saini, Jitender; Pasha, Shaik Afsar; Yadav, Ravi; Pal, Pramod Kumar

    2014-01-01

    Aims: In progressive supranuclear palsy (PSP) tissue damage occurs in specific cortical and subcortical regions. Voxel based analysis using T1-weighted images depict quantitative gray matter (GM) atrophy changes. Magnetization transfer (MT) imaging depicts qualitative changes in the brain parenchyma. The purpose of our study was to investigate whether MT imaging could indicate abnormalities in PSP. Settings and Design: A total of 10 patients with PSP (9 men and 1 woman) and 8 controls (5 men and 3 women) were studied with T1-weighted magnetic resonance imaging (MRI) and 3DMT imaging. Voxel based analysis of T1-weighted MRI was performed to investigate brain atrophy while MT was used to study qualitative abnormalities in the brain tissue. We used SPM8 to investigate group differences (with two sample t-test) using the GM and white matter (WM) segmented data. Results: T1-weighted imaging and MT are equally sensitive to detect changes in GM and WM in PSP. Magnetization transfer ratio images and magnetization-prepared rapid acquisition of gradient echo revealed extensive bilateral volume and qualitative changes in the orbitofrontal, prefrontal cortex and limbic lobe and sub cortical GM. The prefrontal structures involved were the rectal gyrus, medial, inferior frontal gyrus (IFG) and middle frontal gyrus (MFG). The anterior cingulate, cingulate gyrus and lingual gyrus of limbic lobe and subcortical structures such as caudate, thalamus, insula and claustrum were also involved. Cerebellar involvement mainly of anterior lobe was also noted. Conclusions: The findings suggest that voxel based MT imaging permits a whole brain unbiased investigation of central nervous system structural integrity in PSP. PMID:25024571

  20. Prototype continuous flow ventricular assist device supported on magnetic bearings.

    PubMed

    Allaire, P E; Kim, H C; Maslen, E H; Olsen, D B; Bearnson, G B

    1996-06-01

    This article describes a prototype continuous flow pump (CFVAD2) fully supported in magnetic bearings. The pump performance was measured in a simulated adult human circulation system. The pump delivered 6 L/min of flow at 100 mm Hg of differential pressure head operating at 2,400 rpm in water. The pump is totally supported in 4 magnetic bearings: 2 radial and 2 thrust. Magnetic bearings offer the advantages of no required lubrication and large operating clearances. The geometry and other properties of the bearings are described. Bearing parameters such as load capacity and current gains are discussed. Bearing coil currents were measured during operation in air and water. The rotor was operated in various orientations to determine the actuator current gains. These values were then used to estimate the radial and thrust forces acting on the rotor in both air and water. Much lower levels of force were found than were expected, allowing for a very significant reduction in the size of the next prototype. Hemolysis levels were measured in the prototype pump and found not to indicate damage to the blood cells.

  1. Diffeomorphic susceptibility artifact correction of diffusion-weighted magnetic resonance images.

    PubMed

    Ruthotto, L; Kugel, H; Olesch, J; Fischer, B; Modersitzki, J; Burger, M; Wolters, C H

    2012-09-21

    Diffusion-weighted magnetic resonance imaging is a key investigation technique in modern neuroscience. In clinical settings, diffusion-weighted imaging and its extension to diffusion tensor imaging (DTI) are usually performed applying the technique of echo-planar imaging (EPI). EPI is the commonly available ultrafast acquisition technique for single-shot acquisition with spatial encoding in a Cartesian system. A drawback of these sequences is their high sensitivity against small perturbations of the magnetic field, caused, e.g., by differences in magnetic susceptibility of soft tissue, bone and air. The resulting magnetic field inhomogeneities thus cause geometrical distortions and intensity modulations in diffusion-weighted images. This complicates the fusion with anatomical T1- or T2-weighted MR images obtained with conventional spin- or gradient-echo images and negligible distortion. In order to limit the degradation of diffusion-weighted MR data, we present here a variational approach based on a reference scan pair with reversed polarity of the phase- and frequency-encoding gradients and hence reversed distortion. The key novelty is a tailored nonlinear regularization functional to obtain smooth and diffeomorphic transformations. We incorporate the physical distortion model into a variational image registration framework and derive an accurate and fast correction algorithm. We evaluate the applicability of our approach to distorted DTI brain scans of six healthy volunteers. For all datasets, the automatic correction algorithm considerably reduced the image degradation. We show that, after correction, fusion with T1- or T2-weighted images can be obtained by a simple rigid registration. Furthermore, we demonstrate the improvement due to the novel regularization scheme. Most importantly, we show that it provides meaningful, i.e. diffeomorphic, geometric transformations, independent of the actual choice of the regularization parameters.

  2. Diffeomorphic susceptibility artifact correction of diffusion-weighted magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Ruthotto, L.; Kugel, H.; Olesch, J.; Fischer, B.; Modersitzki, J.; Burger, M.; Wolters, C. H.

    2012-09-01

    Diffusion-weighted magnetic resonance imaging is a key investigation technique in modern neuroscience. In clinical settings, diffusion-weighted imaging and its extension to diffusion tensor imaging (DTI) are usually performed applying the technique of echo-planar imaging (EPI). EPI is the commonly available ultrafast acquisition technique for single-shot acquisition with spatial encoding in a Cartesian system. A drawback of these sequences is their high sensitivity against small perturbations of the magnetic field, caused, e.g., by differences in magnetic susceptibility of soft tissue, bone and air. The resulting magnetic field inhomogeneities thus cause geometrical distortions and intensity modulations in diffusion-weighted images. This complicates the fusion with anatomical T1- or T2-weighted MR images obtained with conventional spin- or gradient-echo images and negligible distortion. In order to limit the degradation of diffusion-weighted MR data, we present here a variational approach based on a reference scan pair with reversed polarity of the phase- and frequency-encoding gradients and hence reversed distortion. The key novelty is a tailored nonlinear regularization functional to obtain smooth and diffeomorphic transformations. We incorporate the physical distortion model into a variational image registration framework and derive an accurate and fast correction algorithm. We evaluate the applicability of our approach to distorted DTI brain scans of six healthy volunteers. For all datasets, the automatic correction algorithm considerably reduced the image degradation. We show that, after correction, fusion with T1- or T2-weighted images can be obtained by a simple rigid registration. Furthermore, we demonstrate the improvement due to the novel regularization scheme. Most importantly, we show that it provides meaningful, i.e. diffeomorphic, geometric transformations, independent of the actual choice of the regularization parameters.

  3. Young adults' strategies for managing social support during weight-loss attempts.

    PubMed

    Faw, Meara H

    2014-02-01

    Obesity and being overweight often result in serious health problems. Despite growing awareness of the dangers associated with being overweight, many individuals struggle to lose weight. Investigators have identified social support as a key element in weight-loss attempts. Unfortunately, little has been done to investigate how people solicit social support from members of their pre-existing social network without a structured intervention. To address this limitation, I conducted in-depth interviews with 25 participants. Through grounded theory analysis of these interviews, I developed a typology of support management strategies used by overweight young adults when attempting to lose weight. I outline these strategies, their perceived success, and implications for future research in this article.

  4. Autonomy support and control in weight management: what important others do and say matters.

    PubMed

    Ng, Johan Y Y; Ntoumanis, Nikos; Thøgersen-Ntoumani, Cecilie

    2014-09-01

    Drawing from self-determination theory (Ryan & Deci, 2002, Overview of self-determination theory: An organismic-dialectical perspective. In E. L. Deci & R. M. Ryan (Eds.), Handbook of self-determination research (pp. 3-33). Rochester, NY: The University of Rochester Press.), we examined how individuals' psychological needs, motivation, and behaviours (i.e., physical activity and eating) associated with weight management could be predicted by perceptions of their important others' supportive and controlling behaviours. Using a cross-sectional survey design, 235 participants (mean age = 27.39 years, SD = 8.96 years) completed an online questionnaire. Statistical analyses showed that when important others were perceived to be more supportive, participants reported higher levels of more optimal forms of motivation for weight management, which in turn predicted more physical activity and healthy eating behaviours. In contrast, when important others were perceived to be controlling, participants reported higher levels of less optimal forms of motivation, which in turn predicted less physical activity and healthy eating behaviours, as well as more unhealthy eating behaviours. Significant indirect effects were also found from perceived support and control from important others to physical activity and eating behaviours, all in the expected directions. The findings support the importance of important others providing support and refraining from controlling behaviours in order to facilitate motivation and behaviours conducive to successful weight management. What is already known on this subject? Autonomy support is related to basic need satisfaction and autonomous motivation in the context of weight management. In turn, these variables are related to adaptive outcomes for weight management. What does this study add? Measurement of perceived controlling behaviours by important others. Measurement of perceived need thwarting. Structural model on how important others affect

  5. The effect of deployment, distress, and perceived social support on Army spouses' weight status.

    PubMed

    Fish, Tammy L; Harrington, Donna; Bellin, Melissa H; Shaw, Terry V

    2014-01-01

    This study examined the relationship between deployment status, psychological distress, perceived social support, age, rank, and gender with Army spouses' (N=1863) weight status. We posited that spouses of deployed Soldiers have a higher body mass index (BMI) than spouses of nondeployed Soldiers; spouses with higher psychological distress scores have a higher BMI than those with lower distress scores; and spouses with low social support scores have higher BMIs than those with higher social support scores. Secondary analysis of data from the 2008 Active Duty Spouse Survey was used to examine the relationship between weight status (health versus overweight or obese) and Army spouses' deployment status, demographic characteristics, psychological distress, and perceived social support. Deployment status and weight status were not related (P=.097). Male spouses were significantly more likely than female spouses to be overweight or obese. Psychological distress increased in direct correlation with increased age, and as perceived social support decreased, the incidents of being overweight or obese increased. Findings suggest several risk factors are associated with being overweight or obese: male spouse, noncommissioned officers in the ranks of E5 through E9, older age, higher psychological distress scores, and lower perceived social support scores. The risk factors support the use of the Army Surgeon General's Performance Triad of sleep, activity, and nutrition as a tool to assist Army personnel and Department of the Army civilians in teaching spouses awareness and methods of changing behaviors that may result in choosing healthy options.

  6. Strategies to address weight-based victimization: youths' preferred support interventions from classmates, teachers, and parents.

    PubMed

    Puhl, Rebecca M; Peterson, Jamie Lee; Luedicke, Joerg

    2013-03-01

    Weight-Based Victimization is a frequent experience for adolescents who are overweight or obese, and is associated with numerous psychosocial and physical consequences for those who are targets of victimization. Assessing targets` preferences for different types of support and intervention has been absent in the context of weight-based victimization, but is needed to help inform potential interventions, motivate action, and identify strategies to help adolescents cope with experiences of weight-related teasing or bullying. Adolescents (14-18 years, N = 361, 40 % female, 71 % Caucasian) enrolled in national weight-loss camps completed an on-line survey. Participants who reported previous experiences of weight-based victimization were surveyed about their preferred interventions from peers, friends, teachers, Physical Education (PE) teachers/coaches, and parents. Participants indicated their preferences for specific strategies pertaining to target support, bullying intervention and prevention (e.g., inclusion in peer activities, confronting the bully, telling an adult, and improving anti-bullying policies). Friends (66 %) and peers (58 %) were the most highly preferred intervention agents followed by teachers (55 %), PE teachers/coaches (44 %), and parents (43 %). Participants who experienced more weight-based victimization expressed increased desire for intervention. The frequency of victimization, social support from friends and family, and perceived likelihood and helpfulness of intervention significantly influenced participant preferences for certain types of intervention, although preferences were generally consistent across participants' characteristics. The current study is the first to document youth's preferences for interventions in response to weight-based victimization. The findings have important implications for encouraging appropriate intervention and informing bystanders, which may help to reduce the prevalence, recurrence, and consequences for youth

  7. Basic research support for shared magnetic resonance imaging resources.

    PubMed

    Taylor, Joni; Hampshire, Victoria

    2015-11-01

    Procedures that enable the collection of longitudinal physiologic and anatomic information can contribute to the reduction and refinement of animal use. Scientists are increasingly turning to noninvasive magnetic resonance imaging (MRI) to obtain such information from animal research subjects. As they make this important investment, research support veterinarians are often tasked with ensuring the proper care and use of laboratory animal research subjects. A basic understanding of MRI equipment, personnel practices, safety, and monitoring of animals and their recoveries is key to implementing a centralized animal MRI facility.

  8. Measuring Restriction Sizes Using Diffusion Weighted Magnetic Resonance Imaging: A Review

    PubMed Central

    Martin, Melanie

    2013-01-01

    This article reviews a new concept in magnetic resonance as applied to cellular and biological systems. Diffusion weighted magnetic resonance imaging can be used to infer information about restriction sizes of samples being measured. The measurements rely on the apparent diffusion coefficient changing with diffusion times as measurements move from restricted to free diffusion regimes. Pulsed gradient spin echo (PGSE) measurements are limited in the ability to shorten diffusion times and thus are limited in restriction sizes which can be probed. Oscillating gradient spin echo (OGSE) measurements could provide shorter diffusion times so smaller restriction sizes could be probed. PMID:25114548

  9. A systematic review of the effectiveness of treadmill training and body weight support in pediatric rehabilitation.

    PubMed

    Damiano, Diane L; DeJong, Stacey L

    2009-03-01

    Given the extensive literature on body weight-supported treadmill training (BWSTT) in adult rehabilitation, a systematic review was undertaken to explore the strength, quality, and conclusiveness of evidence supporting use of treadmill training and body weight support in those with pediatric motor disabilities. A secondary goal was to ascertain whether protocol guidelines for BWSTT are available to guide pediatric physical therapy practice. The database search included MEDLINE, EMBASE, CINAHL Plus, PEDro, Cochrane Library databases, and ERIC from January 1, 1980 to May 31, 2008 for articles that included treadmill training and body weight support for individuals under 21 years of age, with or at risk for a motor disability. We identified 277 unique articles from which 29 met all inclusion criteria. Efficacy of treadmill training in accelerating walking development in Down syndrome has been well demonstrated. Evidence supporting efficacy or effectiveness of BWSTT in pediatric practice for improving gait impairments and level of activity and participation in those with cerebral palsy, spinal cord injury, and other central nervous system disorders remains insufficient, although many studies noted positive effects. The original evidence demonstrates efficacy of BWSTT in children with Down syndrome, but large-scale controlled trials are needed to support the use of BWSTT in other pediatric subgroups. Increased use of randomized designs, studies with treadmill training-only groups, and dosage studies are needed before practice guidelines can be formulated. Neural changes in response to training warrant exploration, especially given the capacity for change in developing nervous systems.

  10. Treadmill Training with Partial Body-Weight Support in Children with Cerebral Palsy: A Systematic Review

    ERIC Educational Resources Information Center

    Mutlu, Akmer; Krosschell, Kristin; Spira, Deborah Gaebler

    2009-01-01

    OKAim: The aim of this systematic review was to examine the literature on the effects of partial body-weight support treadmill training (PBWSTT) in children with cerebral palsy (CP) on functional outcomes and attainment of ambulation. Method: We searched the relevant literature from 1950 to July 2007. We found eight studies on the use of PWSBTT on…

  11. Kinematic assessment of treadmill running using different body-weight support harnesses.

    PubMed

    Millslagle, Duane; Levy, Morris; Matack, Nicholas

    2006-10-01

    10 male collegiate runners (M age = 21.4, SD = 1.5 yr.) ran on a treadmill with no body-weight support (BWS), 20% BWS, and 40% BWS conditions. In addition, they wore three different commercially available harnesses at the 20% and 40% BWS conditions. The aim was to run on the treadmill at a fast speed while maintaining an adequate step length. The purpose was to investigate how each harness changed running gait, and the differences in running gait between the harnesses with various body-weight support. Analysis of variance indicated significant restriction of upper body torso rotation between the harnesses at the 40% BWS conditions. Body-weight support resulted in a longer stride, decreased cadence, less vertical displacement of the center of mass, and diminished hip and ankle joint excursions. These changes indicated that increased body-weight support results in longer steps with the foot contacting the belt for a shorter period of time with less leg angular changes throughout the running cycling.

  12. Interlimb Coordination in Body-Weight Supported Locomotion: A Pilot Study

    PubMed Central

    Seiterle, Stefan; Susko, Tyler; Artemiadis, Panagiotis K.; Riener, Robert; Krebs, Hermano Igo

    2015-01-01

    Locomotion involves complex neural networks responsible for automatic and volitional actions. During locomotion, motor strategies can rapidly compensate for any obstruction or perturbation that could interfere with forward progression. In this pilot study, we examined the contribution of interlimb pathways for evoking muscle activation patterns in the contralateral limb when a unilateral perturbation was applied and in the case where body weight was externally supported. In particular, the latency of neuromuscular responses was measured, while the stimulus to afferent feedback was limited. The pilot experiment was conducted with six healthy young subjects. It employed the MIT-Skywalker (beta-prototype), a novel device intended for gait therapy. Subjects were asked to walk on the split-belt treadmill, while a fast unilateral perturbation was applied mid-stance by unexpectedly lowering one side of the split-treadmill walking surfaces. Subject's weight was externally supported via the body-weight support system consisting of an underneath bicycle seat and the torso was stabilized via a loosely fitted chest harness. Both the weight support and the chest harness limited the afferent feedback. The unilateral perturbations evoked changes in the electromyographic activity of the non-perturbed contralateral leg. The latency of all muscle responses exceeded 100 ms, which precludes the conjecture that spinal cord alone is responsible for the perturbation response. It suggests the role of supraspinal or midbrain level pathways at the inter-leg coordination during gait. PMID:25990210

  13. Treadmill Training with Partial Body-Weight Support in Children with Cerebral Palsy: A Systematic Review

    ERIC Educational Resources Information Center

    Mutlu, Akmer; Krosschell, Kristin; Spira, Deborah Gaebler

    2009-01-01

    OKAim: The aim of this systematic review was to examine the literature on the effects of partial body-weight support treadmill training (PBWSTT) in children with cerebral palsy (CP) on functional outcomes and attainment of ambulation. Method: We searched the relevant literature from 1950 to July 2007. We found eight studies on the use of PWSBTT on…

  14. Interlimb coordination in body-weight supported locomotion: A pilot study.

    PubMed

    Seiterle, Stefan; Susko, Tyler; Artemiadis, Panagiotis K; Riener, Robert; Igo Krebs, Hermano

    2015-08-20

    Locomotion involves complex neural networks responsible for automatic and volitional actions. During locomotion, motor strategies can rapidly compensate for any obstruction or perturbation that could interfere with forward progression. In this pilot study, we examined the contribution of interlimb pathways for evoking muscle activation patterns in the contralateral limb when a unilateral perturbation was applied and in the case where body weight was externally supported. In particular, the latency of neuromuscular responses was measured, while the stimulus to afferent feedback was limited. The pilot experiment was conducted with six healthy young subjects. It employed the MIT-Skywalker (beta-prototype), a novel device intended for gait therapy. Subjects were asked to walk on the split-belt treadmill, while a fast unilateral perturbation was applied mid-stance by unexpectedly lowering one side of the split-treadmill walking surfaces. Subject's weight was externally supported via the body-weight support system consisting of an underneath bicycle seat and the torso was stabilized via a loosely fitted chest harness. Both the weight support and the chest harness limited the afferent feedback. The unilateral perturbations evoked changes in the electromyographic activity of the non-perturbed contralateral leg. The latency of all muscle responses exceeded 100ms, which precludes the conjecture that spinal cord alone is responsible for the perturbation response. It suggests the role of supraspinal or midbrain level pathways at the inter-leg coordination during gait.

  15. Development of high frequency low weight power magnetics for aerospace power systems

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.

    1984-01-01

    A dominant design consideration in the development of space type power mangetic devices is the application of reliable thermal control methods to prevent device failure which is due to excessive temperature rises and hot temperatures in critical areas. The resultant design must also yield low weight, high efficiency, high reliability and maintainability, and long life. The weight savings and high efficiency that results by going to high frequency and unique thermal control techniques is demonstrated by the development of a 25 kVA, 20 kHz space type transformer under the power magnetics technology program. Work in the area of power rotary transformer is also discussed.

  16. Collapse and Fragmentation of Magnetically-Supported Infinite Sheets

    NASA Astrophysics Data System (ADS)

    Boss, A. P.

    2004-12-01

    The collapse and fragmentation of initially sheet-like, magnetic molecular clouds is calculated in three dimensions with a gravitational, radiative hydrodynamics code. The code includes a crude representation of magnetic field effects and ambipolar diffusion, through the magnetic pressure and magnetic tension approximations, and a simple parameterization based on previous magnetohydrodynamical calculations, respectively. The computational volume is a spherical portion of an initially isothermal, infinite sheet of self-gravitating gas, symmetric about its midplane, with the portion of the cloud exterior to the spherical volume being represented through its effect on the gravitational potential inside the spherical volume. The gas layer is initially in hydrostatic equilibrium, but with a mass equal to or greater than the critical mass ( ˜ 1 M⊙) for the growth of gravitational instability. The magnetic field pressure acts to further stabilize the initial cloud. Over 106 active grid points are employed in the models, sufficient to resolve the Jeans length and so avoid artificial fragmentation. The parameters varied are the ratio of the ambipolar diffusion time to the midplane free fall time (10 or 20), the cloud's reference magnetic field strength (100 or 200 microgauss), the ratio of rotational to gravitational energy of the sheet (0.0 or 0.01), and the form of the initial density perturbation applied to the infinite sheet. Three types of outcomes are observed: formation of one or two protostars near the edge of the spherical volume, formation of a protostar near (but not at) the center of the cloud, or formation of a rotating ring near the center of the cloud, which appears likely to fragment into two or more protostars. Flow speeds of ˜ 0.1 km s-1 are generated as the sheet begins to break-up into collapsing protostars. The forming protostars are separated by distances approximately equal to the cloud diameter, consistent with the spacing predicted by the linear

  17. Teacher and Friend Social Support: Association with Body Weight in African-American Adolescent Females

    PubMed Central

    Stanford, Jevetta; Webb, Fern J.; Lee, Jenny; Doldren, Michelle; Rathore, Mobeen

    2016-01-01

    The purpose of this study was to examine the direct and indirect ecological influences of teacher and friend social support on body weight and diet behaviors in African-American adolescent females. Using a quantitative, cross-sectional research design, a convenience sample of 182 urban African-American adolescent females (12–17 years old) completed a 39-item questionnaire. The questionnaire assessed perceived teacher social support, friend social support, nutrition self-efficacy, and diet behaviors (with internal reliability values of scale items: alpha=0.74, 0.81, 0.77, and 0.69 respectively). Anthropometric assessments were conducted to measure height and weight to compute BMI. Majority of the participants were in middle or early high school (65 %) and were overweight or obese (57.7 %). Both teacher social support and friend social support demonstrated a positive, indirect influence on child weight status through nutrition self-efficacy and diet behaviors following two different and specific paths of influence. Diet behaviors, in turn, demonstrated a positive, direct effect on child weight status. In the structural model, teacher social support had the greatest effect on diet behaviors, demonstrating a direct, positive influence on diet behaviors (B=0.421, p<0.05), but its direct effect on nutrition self-efficacy was not significant. Friend social support demonstrated a positive, direct effect on nutrition self-efficacy (B=0.227, p<0.05), but its direct effect on diet behaviors was not statistically significant. The study’s findings call for actively addressing the childhood obesity epidemic in the school environment by implementing health behavior change strategies at various social and ecological environmental levels. PMID:26863465

  18. Teacher and Friend Social Support: Association with Body Weight in African-American Adolescent Females.

    PubMed

    Stanford, Jevetta; Khubchandani, Jagdish; Webb, Fern J; Lee, Jenny; Doldren, Michelle; Rathore, Mobeen

    2015-09-01

    The purpose of this study was to examine the direct and indirect ecological influences of teacher and friend social support on body weight and diet behaviors in African-American adolescent females. Using a quantitative, cross-sectional research design, a convenience sample of 182 urban African-American adolescent females (12-17 years old) completed a 39-item questionnaire. The questionnaire assessed perceived teacher social support, friend social support, nutrition self-efficacy, and diet behaviors (with internal reliability values of scale items: alpha = 0.74, 0.81, 0.77, and 0.69 respectively). Anthropometric assessments were conducted to measure height and weight to compute BMI. Majority of the participants were in middle or early high school (65 %) and were overweight or obese (57.7 %). Both teacher social support and friend social support demonstrated a positive, indirect influence on child weight status through nutrition self-efficacy and diet behaviors following two different and specific paths of influence. Diet behaviors, in turn, demonstrated a positive, direct effect on child weight status. In the structural model, teacher social support had the greatest effect on diet behaviors, demonstrating a direct, positive influence on diet behaviors (B = 0.421, p < 0.05), but its direct effect on nutrition self-efficacy was not significant. Friend social support demonstrated a positive, direct effect on nutrition self-efficacy (B = 0.227, p < 0.05), but its direct effect on diet behaviors was not statistically significant. The study's findings call for actively addressing the childhood obesity epidemic in the school environment by implementing health behavior change strategies at various social and ecological environmental levels.

  19. The design of anisotropic diffusion phantoms for the validation of diffusion weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Fieremans, Els; DeDeene, Yves; Delputte, Steven; Özdemir, Mahir S.; Achten, Eric; Lemahieu, Ignace

    2008-10-01

    Diffusion weighted magnetic resonance imaging offers a non-invasive tool to explore the three-dimensional structure of brain white matter in clinical practice. Anisotropic diffusion hardware phantoms are useful for the quantitative validation of this technique. This study provides guidelines on how to manufacture anisotropic fibre phantoms in a reproducible way and which fibre material to choose to obtain a good quality of the diffusion weighted images. Several fibre materials are compared regarding their effect on the diffusion MR measurements of the water molecules inside the phantoms. The diffusion anisotropy influencing material properties are the fibre density and diameter, while the fibre surface relaxivity and magnetic susceptibility determine the signal-to-noise ratio. The effect on the T2-relaxation time of water in the phantoms has been modelled and the diffusion behaviour inside the fibre phantoms has been quantitatively evaluated using Monte Carlo random walk simulations.

  20. Dynamic Susceptibility Contrast Perfusion-Weighted Magnetic Resonance Imaging and Diffusion-Weighted Magnetic Resonance Imaging in Differentiating Recurrent Head and Neck Cancer From Postradiation Changes.

    PubMed

    Abdel Razek, Ahmed Abdel Khalek; Gaballa, Gada; Ashamalla, Germin; Alashry, Mohamed Saad; Nada, Nadia

    2015-01-01

    The aim of this study was to assess dynamic susceptibility contrast (DSC) perfusion-weighted magnetic resonance (MR) imaging and diffusion-weighted MR imaging in differentiating recurrent head and neck cancer from postradiation changes. A prospective study was done on 41 patients with head and neck cancer after radiotherapy who underwent diffusion-weighted MR imaging, DSC perfusion-weighted MR imaging, and routine postcontrast MR imaging. The apparent diffusion coefficient (ADC) map and time signal intensity curve of the lesion were created. The ADC value, DSC percentage (DSC%), and contrast enhancement percentage of the lesion were calculated. The final diagnosis was done with biopsy. There was significant difference (P = 0.001) in ADC between recurrent cancer (0.94 ± 0.16 × 10mm/s) and postradiation changes (1.37 ± 0.12 × 10mm/s). There was significant difference (P = 0.001) in DSC% of recurrent cancer (30.9% ± 5.16%) and postradiation changes (12.1% ± 3.06%). Selection of ADC equal to or less than 1.07 × 10mm/s and DSC% greater than 16.6% to predict recurrence have areas under the curve of 0.822 and 0.900 and accuracy of 92.7% and 95.1%, respectively. Combination of ADC and DSC% has are under the curve of 0.992 and accuracy of 97.6%. Combined ADC and DSC% are noninvasive imaging parameters that can play a role in the differentiation of recurrent head and neck cancer from postradiation changes.

  1. Micronanostructures of the scales on a mosquito's legs and their role in weight support

    NASA Astrophysics Data System (ADS)

    Wu, C. W.; Kong, X. Q.; Wu, Diane

    2007-07-01

    We show here that the mosquito cannot only give rise to a higher water-supporting force than the water strider if the ratio of the water-supporting force to the body weight of the insect itself is compared, but also can safely take off or land on the water surface, and also can attach on any solid surface like the fly. We found that the mosquito’s legs are covered by numerous scales consisting of the uniform microscale longitudinal ridges (nanoscale thickness and microscale spacing between) and nanoscale cross ribs (nanoscale thickness and spacing between). Such special delicate microstructure and/or nanostructure on the leg surface give a water contact angle of ˜153° and give a surprising high water-supporting ability. It was found that the water-supporting force of a single leg of the mosquito is about 23 times the body weight of the mosquito, compared with a water strider’s leg giving a water-supporting force of about 15 times the body weight of the insect.

  2. Influence of 7 days of hindlimb suspension and intermittent weight support on rat muscle mechanical properties

    NASA Technical Reports Server (NTRS)

    Pierotti, David J.; Roy, Roland R.; Flores, Vinicio; Edgerton, Reggie

    1990-01-01

    The effect of intermittent periods of weight support on a decrease in mass of the soleus (Sol) and medial gastrocnemius (MG) muscles atrophied by hindlimb suspension (HS) was investigated in rats subjected to continuous HS for seven days or an HS plus intermittent (10 min every 6 hrs of slow walking on a treadmill) weight support (HS-WS). After 7 d HS, the Sol weight relative to body weight was 21 and 9 percent lower in Hs and HS-WS, respectively, than in control rats. Maximum tetanic tension/muscle mass ratio was significantly lower in HS than in controls; the HS-WS rats had values similar to controls, whereas the maximum tetanic tension/muscle weight was significantly elevated in HS-WS compared to controls. Contraction times were 25 percent faster in the Sol and unchanged in the MG of HS rats, indicating that a low-force short-duration exercise regime results in a significant functional recovery in the 'slow' Sol, whereas the 'fast' MG is less affected.

  3. Wearable devices and mobile technologies for supporting behavioral weight loss among people with serious mental illness.

    PubMed

    Naslund, John A; Aschbrenner, Kelly A; Scherer, Emily A; McHugo, Gregory J; Marsch, Lisa A; Bartels, Stephen J

    2016-10-30

    Promoting physical activity is essential for addressing elevated cardiovascular risk and high obesity rates affecting people with serious mental illness. Numerous challenges interfere with exercise participation in this high-risk group including mental health symptoms, low motivation, and limited access to safe and affordable options for physical activity. Wearable devices and mobile health technologies may afford new opportunities for promoting physical activity and supporting behavioral weight loss efforts. This exploratory study examined whether daily step count measured using Fitbit wearable devices was associated with weight loss and improved fitness among individuals with serious mental illness enrolled in a 6-month lifestyle program. Participants (n=34) had a schizophrenia spectrum disorder (23.5%), major depression (50.0%), or bipolar disorder (26.5%), and wore Fitbits most of the days (M=86.2%; SD=18.4%) they were enrolled in the study. At 6-months, higher average daily step count was associated with greater weight loss (F=5.07; df=1,32; p=0.0314), but not improved fitness (F=1.92; df=1,31; p=0.176). These findings demonstrate that encouraging participants with serious mental illness enrolled in lifestyle interventions to collect more steps may contribute to greater weight loss. This suggests that wearable devices may offer a feasible and potentially effective strategy for supporting behavioral weight loss in community mental health settings.

  4. Water-dispersible magnetic carbon nanotubes as T2-weighted MRI contrast agents.

    PubMed

    Liu, Yue; Hughes, Timothy C; Muir, Benjamin W; Waddington, Lynne J; Gengenbach, Thomas R; Easton, Christopher D; Hinton, Tracey M; Moffat, Bradford A; Hao, Xiaojuan; Qiu, Jieshan

    2014-01-01

    An efficient MRI T2-weighted contrast agent incorporating a potential liver targeting functionality was synthesized via the combination of superparamagnetic iron oxide (SPIO) nanoparticles with multiwalled carbon nanotubes (MWCNTs). Poly(diallyldimethylammonium chloride) (PDDA) was coated on the surface of acid treated MWCNTs via electrostatic interactions and SPIO nanoparticles modified with a potential targeting agent, lactose-glycine adduct (Lac-Gly), were subsequently immobilized on the surface of the PDDA-MWCNTs. A narrow magnetic hysteresis loop indicated that the product displayed superparamagnetism at room temperature which was further confirmed by ZFC (zero field cooling)/FC (field cooling) curves measured by SQUID. The multifunctional MWCNT-based magnetic nanocomposites showed low cytotoxicity in vitro to HEK293 and Huh7 cell lines. Enhanced T2 relaxivities were observed for the hybrid material (186 mM(-1) s(-1)) in comparison with the pure magnetic nanoparticles (92 mM(-1) s(-1)) due to the capacity of the MWCNTs to "carry" more nanoparticles as clusters. More importantly, after administration of the composite material to an in vivo liver cancer model in mice, a significant increase in tumor to liver contrast ratio (277%) was observed in T2 weighted magnetic resonance images. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  5. Supporting self-efficacy through interactive discussion in online communities of weight loss.

    PubMed

    Wang, Ye; Willis, Erin

    2016-06-22

    By conducting a content analysis of online communities connected by the Weight Watchers' online message boards, this study examined the relationship between conversational interactivity and consumer-generated content about consumer health information, self-efficacious content, and experiences with dieting and physical activities. The results showed that discussion about successful experiences with weight loss tended to be more interactive. Discussion about consumer health information tended to be non-interactive. The findings suggest that online communities generate social support through interactive discussion about successful experiences, and the interactive discussion, in return, sustains active participation in the community.

  6. Minimum classification error-based weighted support vector machine kernels for speaker verification.

    PubMed

    Suh, Youngjoo; Kim, Hoirin

    2013-04-01

    Support vector machines (SVMs) have been proved to be an effective approach to speaker verification. An appropriate selection of the kernel function is a key issue in SVM-based classification. In this letter, a new SVM-based speaker verification method utilizing weighted kernels in the Gaussian mixture model supervector space is proposed. The weighted kernels are derived by using the discriminative training approach, which minimizes speaker verification errors. Experiments performed on the NIST 2008 speaker recognition evaluation task showed that the proposed approach provides substantially improved performance over the baseline kernel-based method.

  7. Automated prostate cancer detection using T2-weighted and high-b-value diffusion-weighted magnetic resonance imaging

    PubMed Central

    Kwak, Jin Tae; Xu, Sheng; Wood, Bradford J.; Turkbey, Baris; Choyke, Peter L.; Pinto, Peter A.; Wang, Shijun; Summers, Ronald M.

    2015-01-01

    Purpose: The authors propose a computer-aided diagnosis (CAD) system for prostate cancer to aid in improving the accuracy, reproducibility, and standardization of multiparametric magnetic resonance imaging (MRI). Methods: The proposed system utilizes two MRI sequences [T2-weighted MRI and high-b-value (b = 2000 s/mm2) diffusion-weighted imaging (DWI)] and texture features based on local binary patterns. A three-stage feature selection method is employed to provide the most discriminative features. The authors included a total of 244 patients. Training the CAD system on 108 patients (78 MR-positive prostate cancers and 105 benign MR-positive lesions), two validation studies were retrospectively performed on 136 patients (68 MR-positive prostate cancers, 111 benign MR-positive lesions, and 117 MR-negative benign lesions). Results: In distinguishing cancer from MR-positive benign lesions, an area under receiver operating characteristic curve (AUC) of 0.83 [95% confidence interval (CI): 0.76–0.89] was achieved. For cancer vs MR-positive or MR-negative benign lesions, the authors obtained an AUC of 0.89 AUC (95% CI: 0.84–0.93). The performance of the CAD system was not dependent on the specific regions of the prostate, e.g., a peripheral zone or transition zone. Moreover, the CAD system outperformed other combinations of MRI sequences: T2W MRI, high-b-value DWI, and the standard apparent diffusion coefficient (ADC) map of DWI. Conclusions: The novel CAD system is able to detect the discriminative texture features for cancer detection and localization and is a promising tool for improving the quality and efficiency of prostate cancer diagnosis. PMID:25979032

  8. Hybrid nanotrimers for dual T1 and T2-weighted magnetic resonance imaging

    DOE PAGES

    Cheng, Kai; Yang, Meng; Zhang, Ruiping; ...

    2014-10-04

    Development of multifunctional nanoparticle-based probes for dual T1- and T2-weighted magnetic resonance imaging (MRI) could allow us to image and diagnose the tumors or other abnormalities in an exceptionally accurate and reliable manner. In this study, by fusing distinct nanocrystals via solid-state interfaces, we built hybrid heteronanostructures to combine both T1 and T2- weighted contrast agents together for MRI with high accuracy and reliability. The resultant hybrid heterotrimers showed high stability in physiological conditions and could induce both simultaneous positive and negative contrast enhancements in MR images. Small animal positron emission tomography imaging study revealed that the hybrid heterostructures displayedmore » favorable biodistribution and were suitable for in vivo imaging. Furthermore, their potential as dual contrast agents for T1 and T2-weighted MRI was further demonstrated by in vitro and in vivo imaging and relaxivity measurements.« less

  9. Magnetic resonance characteristics and susceptibility weighted imaging of the brain in gadolinium encephalopathy.

    PubMed

    Samardzic, Dejan; Thamburaj, Krishnamoorthy

    2015-01-01

    To report the brain imaging features on magnetic resonance imaging (MRI) in inadvertent intrathecal gadolinium administration. A 67-year-old female with gadolinium encephalopathy from inadvertent high dose intrathecal gadolinium administration during an epidural steroid injection was studied with multisequence 3T MRI. T1-weighted imaging shows pseudo-T2 appearance with diffusion of gadolinium into the brain parenchyma, olivary bodies, and membranous labyrinth. Nulling of cerebrospinal fluid (CSF) signal is absent on fluid attenuation recovery (FLAIR). Susceptibility-weighted imaging (SWI) demonstrates features similar to subarachnoid hemorrhage. CT may demonstrate a pseudo-cerebral edema pattern given the high attenuation characteristics of gadolinium. Intrathecal gadolinium demonstrates characteristic imaging features on MRI of the brain and may mimic subarachnoid hemorrhage on susceptibility-weighted imaging. Identifying high dose gadolinium within the CSF spaces on MRI is essential to avoid diagnostic and therapeutic errors. Copyright © 2013 by the American Society of Neuroimaging.

  10. Hybrid Nanotrimers for Dual T1 and T2-Weighted Magnetic Resonance Imaging

    PubMed Central

    2015-01-01

    Development of multifunctional nanoparticle-based probes for dual T1- and T2-weighted magnetic resonance imaging (MRI) could allow us to image and diagnose the tumors or other abnormalities in an exceptionally accurate and reliable manner. In this study, by fusing distinct nanocrystals via solid-state interfaces, we built hybrid heteronanostructures to combine both T1 and T2- weighted contrast agents together for MRI with high accuracy and reliability. The resultant hybrid heterotrimers showed high stability in physiological conditions and could induce both simultaneous positive and negative contrast enhancements in MR images. Small animal positron emission tomography imaging study revealed that the hybrid heterostructures displayed favorable biodistribution and were suitable for in vivo imaging. Their potential as dual contrast agents for T1 and T2-weighted MRI was further demonstrated by in vitro and in vivo imaging and relaxivity measurements. PMID:25283972

  11. Toxicity and T₂-Weighted Magnetic Resonance Imaging Potentials of Holmium Oxide Nanoparticles.

    PubMed

    Atabaev, Timur Sh; Shin, Yong Cheol; Song, Su-Jin; Han, Dong-Wook; Hong, Nguyen Hoa

    2017-08-07

    In recent years, paramagnetic nanoparticles (NPs) have been widely used for magnetic resonance imaging (MRI). This paper reports the fabrication and toxicity evaluation of polyethylene glycol (PEG)-functionalized holmium oxide (Ho₂O₃) NPs for potential T₂-weighted MRI applications. Various characterization techniques were used to examine the morphology, structure and chemical properties of the prepared PEG-Ho₂O₃ NPs. MRI relaxivity measurements revealed that PEG-Ho₂O₃ NPs could generate a strong negative contrast in T₂-weighted MRI. The pilot cytotoxicity experiments showed that the prepared PEG-Ho₂O₃ NPs are biocompatible at concentrations less than 16 μg/mL. Overall, the prepared PEG-Ho₂O₃ NPs have potential applications for T₂-weighted MRI imaging.

  12. A six-axis hybrid vibration isolation system using active zero-power control supported by passive weight support mechanism

    NASA Astrophysics Data System (ADS)

    Emdadul Hoque, Md.; Mizuno, Takeshi; Ishino, Yuji; Takasaki, Masaya

    2010-08-01

    This paper presents a six-degree-of-freedom hybrid vibration isolation system integrated with an active negative suspension, an active-passive positive suspension and a passive weight support mechanism. The aim of the research consists in maximizing the system and control performances, and minimizing the system development and maintenance costs. The vibration isolation system is, fundamentally, developed by connecting an active negative suspension realized by zero-power control in series with an active-passive positive suspension. The system could effectively isolate ground vibrations in addition to suppress the effect of on-board generated direct disturbances of the six-axis motions, associated with vertical and horizontal directions. The system is further reinforced by introducing a passive weight support mechanism in parallel with the basic system. The modified system with zero-power control allows simplified design of the isolation table without power consumption. It also offers enhanced performance on direct disturbance suppression and large payload supporting capabilities, without degrading transmissibility characteristics. A mathematical model of the system is presented and, therefore, analyzed to demonstrate that zero-compliance to direct disturbance could be generated by the developed system. Experimental demonstrations validate the proposed concept that exhibits high stiffness of the isolation table to static and dynamic direct disturbances, and good transmissibility characteristics against ground vibration. Further improvements of the vibration isolation system and the control system are discussed as well.

  13. Social support for healthy behaviors: Scale psychometrics and prediction of weight loss among women in a behavioral program

    PubMed Central

    Kiernan, Michaela; Moore, Susan D.; Schoffman, Danielle E.; Lee, Katherine; King, Abby C.; Taylor, C. Barr; Kiernan, Nancy Ellen; Perri, Michael G.

    2015-01-01

    Social support could be a powerful weight-loss treatment moderator or mediator but is rarely assessed. We assessed the psychometric properties, initial levels, and predictive validity of a measure of perceived social support and sabotage from friends and family for healthy eating and physical activity (eight subscales). Overweight/obese women randomized to one of two 6-month, group-based behavioral weight-loss programs (N=267; mean BMI 32.1±3.5; 66.3% White) completed subscales at baseline, and weight loss was assessed at 6 months. Internal consistency, discriminant validity, and content validity were excellent for support subscales and adequate for sabotage subscales; qualitative responses revealed novel deliberate instances not reflected in current sabotage items. Most women (>75%) “never” or “rarely” experienced support from friends or family. Using non-parametric classification methods, we identified two subscales—support from friends for healthy eating and support from family for physical activity—that predicted three clinically meaningful subgroups who ranged in likelihood of losing ≥5% of initial weight at 6 months. Women who “never” experienced family support were least likely to lose weight (45.7% lost weight) whereas women who experienced both frequent friend and family support were more likely to lose weight (71.6% lost weight). Paradoxically, women who “never” experienced friend support were most likely to lose weight (80.0% lost weight), perhaps because the group-based programs provided support lacking from friendships. Psychometrics for support subscales were excellent; initial support was rare; and the differential roles of friend versus family support could inform future targeted weight-loss interventions to subgroups at risk. PMID:21996661

  14. Effects of periodic weight support on medial gastrocnemius fibers of suspended rats

    NASA Technical Reports Server (NTRS)

    Graham, Scot C.; Roy, Roland R.; Hauschka, Edward O.; Edgerton, V. Reggie

    1989-01-01

    The effects of seven-day-long hindlimb suspension (HS) and HS plus daily periodic weight support activity on the size and metabolic properties of individual fibers in the medial gastrocnemius (MG) of rats were examined. Sections of muscle tissue removed after seven day suspension were stained quantitatively for succinate dehydrogenase and alpha-glycerophosphate dehydrogenase, and qualitatively for myosin ATPase. It was found that short intermittent periods of weight support had a beneficial effect in maintaining the size and metabolic properties of both dark and light ATPase fibers in the deep regions (i.e., close to the bone) and of dark ATPase fibers in the superficial regions of the MG. The effect was greater in the deep regions.

  15. A Systematic Review of the Effectiveness of Treadmill Training and Body Weight Support in Pediatric Rehabilitation

    PubMed Central

    Damiano, Diane L.; DeJong, Stacey L.

    2010-01-01

    Background & Purpose Given the extensive literature on body weight supported treadmill training (BWSTT) in adult rehabilitation, a systematic review was undertaken to explore the strength, quality and conclusiveness of the scientific evidence supporting the use of treadmill training and body weight support in those with pediatric motor disabilities. A secondary goal was to ascertain whether sufficient protocol guidelines for BWSTT are as yet available to guide pediatric physical therapy practice. Methods The database search included MEDLINE, EMBASE, CINAHL Plus (Cumulative Index to Nursing and Allied Health Literature), PEDro (Physiotherapy Evidence Database), Cochrane Library databases, and ERIC (Education Resources Information Center) from January 1, 1980 until May 31, 2008 for all articles that included treadmill training and body weight support alone or in combination for individuals under 21 years of age, with or at risk for having a motor disability. We identified 277 unique articles from which 29 met all inclusion criteria Results Efficacy of treadmill training in accelerating walking development in Down syndrome has been well-demonstrated. Evidence supporting the efficacy or effectiveness of BWSTT in pediatric practice for improving gait impairments and level of activity and participation in those with cerebral palsy, spinal cord injuries, and other central nervous system disorders remains insufficient even though many studies noted positive, yet small, effects. Increased use of randomized designs, studies with treadmill training only groups, and dosage studies are needed before practice guidelines can be formulated. Neural changes in response to training warrant greater exploration, especially given the capacity for change in developing nervous systems. Discussion and Conclusion Large scale controlled trials are critically needed to support the use of BWSTT in specific pediatric patient sub-groups and to define optimal protocol parameters. PMID:19265768

  16. Bifurcation Behavior of a Rotor Supported by Active Magnetic Bearings

    NASA Astrophysics Data System (ADS)

    JI, J. C.; YU, L.; LEUNG, A. Y. T.

    2000-08-01

    The non-linear dynamics of a rigid rotor levitated by active magnetic bearings is investigated. The vibrations in the horizontal and vertical directions are analyzed on the center manifold near the double-zero degenerate point by using normal-form method. The resulting normal forms in the horizontal and vertical directions are different due to the effect of rotor weight. It is shown that the vibratory behavior in the vertical direction can be reduced on the center manifold to the Bogdanov-Takens form. For the autonomous case, there exist saddle-node bifurcation and Hopf bifurcation for local analysis, and a saddle-connection bifurcation for global analysis. For non-autonomous case, the Melnikov technique is used to determine the critical parameter at which the homoclinic orbits intersect transversally. For the vibrations in the horizontal direction, the essential non-linear terms of the truncated normal form are third order. The behaviors of zero solutions are given. Finally, numerical simulations are performed to verify the analytical predictions.

  17. Breast milk expression and maintenance in mothers of very low birth weight infants: supports and barriers.

    PubMed

    Sisk, Paula; Quandt, Sara; Parson, Nikki; Tucker, Jenna

    2010-11-01

    The study objective was to identify patterns of factors that supported or hindered initiation of breast milk expression and maintenance of breast milk production after the birth of a very low birth weight (VLBW) infant in a sample of US women with varied prenatal infant feeding intentions. In-depth interviews were conducted 1 to 6 months after delivery in 32 women who initiated breast milk expression after encouragement from hospital staff. Pregnancy complications, anxiety regarding their infant's health, and lack of privacy interfered with initiation of milk expression. After hospital discharge, using manual or small electric breast pumps, travel to the neonatal intensive care unit, return to work, and difficulty with time management interfered with maintenance of breast milk production. Family support, positive attitudes toward pumping, and anticipation of breastfeeding supported maintenance of breast milk production. From these data emerge points of intervention where additional support could improve mothers' experiences and increase duration of breast milk feeding.

  18. Arm weight support training improves functional motor outcome and movement smoothness after stroke

    PubMed Central

    Bartolo, Michelangelo; De Nunzio, Alessandro Marco; Sebastiano, Fabio; Spicciato, Francesca; Tortola, Paolo; Nilsson, Jan; Pierelli, Francesco

    2014-01-01

    Summary The aim of this study was to compare the effectiveness in acute stroke patients of a rehabilitation program performed with or without an arm weight support device. Twenty-eight acute, first-ever unilateral stroke patients were enrolled in a single-blind, randomized controlled trial. Clinical evaluation included Fugl-Mayer Assessment, Functional Independence Measure and kinematic analysis [maximum and mean hand velocity, maximum range of motion (Max RoM), normalized jerk (NJ)]. Patients received 12 daily 30-minute sessions (6/week) of additional upper limb therapy performed using an arm weight support device (study group) or additional traditional physiotherapy (control group). The patients were evaluated on admission and at the end of the rehabilitation intervention. The two groups were clinically comparable on admission (p>0.05). Both groups showed significant improvements in clinical scale scores and in Max RoM in flexion-extension, while only the study group showed improvements in NJ and in Max RoM in adduction-abduction. Rehabilitation training using an arm weight support device appears to be a useful method to supplement conventional therapy in acute stroke patients, increasing smoothness of movement and motor function. PMID:25014045

  19. A three-degree-of-freedom hybrid vibration isolation system using adaptive proportional control supported by passive weight support mechanism

    NASA Astrophysics Data System (ADS)

    Liu, Yun-Hui; Wu, Wei-Hao; Chu, Chih-Liang

    2013-10-01

    This paper presents a three-degree-of-freedom hybrid vibration isolation system integrated with an active sky-hook damper and a passive weight support mechanism for highly sensitive measurement equipment, e.g. atomic force microscopes, suffering from building vibration. Active sky-hook damper applies proportional controller incorporated with an adaptive filter to reduce the resonance of the passive weight support mechanism at nature frequency. The absolute vibration velocity signal acquired from an accelerator and being processed through an integrator is input to the controller as a feedback signal, and the controller output signal drives the voice coil actuator to produce a sky-hook damper force. The adaptive filter is used to compensate the phase error between the measuring input signal and the absolute vibration velocity. An analysis of this active vibration isolation system is presented, and model predictions are compared to experimental results. The results show that the system could effectively reduce transmissibility at resonance without the penalty of increased transmissibility at higher frequencies both in vertical and horizontal directions.

  20. Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques.

    PubMed

    Tsolaki, Evangelia; Kousi, Evanthia; Svolos, Patricia; Kapsalaki, Efthychia; Theodorou, Kyriaki; Kappas, Constastine; Tsougos, Ioannis

    2014-04-28

    In recent years, advanced magnetic resonance imaging (MRI) techniques, such as magnetic resonance spectroscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic problems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical decision support systems (CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually increased. Hence, the purpose of the current review article is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be introduced into intelligent systems to significantly improve their diagnostic specificity and clinical application.

  1. Treadmill training with partial body weight support in nonambulatory patients with cerebral palsy.

    PubMed

    Schindl, M R; Forstner, C; Kern, H; Hesse, S

    2000-03-01

    To examine the potential role of treadmill training with partial body weight support in nonambulatory children with cerebral palsy. Open, nonrandomized, baseline-treatment study. An outpatient rehabilitation clinic. Ten children with cerebral palsy. Six children (group A) were nonambulatory, and four children (group B) either required continuous physical help (two cases) or were able to walk short distances with a stand-by or independently (one case each). Three months of additional treadmill training, three times a week, 25 minutes a session. Functional Ambulation Categories, standing and walking section of the Gross Motor Function Measure, assessed at two baseline measurements 6 and 3 weeks before the study onset, at the beginning, and at the end of therapy. Measurements during baseline and at the study onset did not differ. During therapy, the mean Functional Ambulation Category improved significantly from 1.1 to 1.9 (p<.05). The sum score of the standing section of the Gross Motor Function Measure increased by 47% (p<.05). The walking section score increased by 50% (p<.01). Of the six nonambulant children in group A, transfer abilities improved in four, one child could walk short distances independently, and two children could walk with continuous physical support after therapy. Of group B, one child could climb stairs independently, three children only needed verbal support while walking, and all subjects could then stand up arm-free after therapy. Treadmill training with partial body weight support is a promising treatment technique in nonambulatory children with cerebral palsy.

  2. Conductivity tensor imaging of the brain using diffusion-weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Sekino, Masaki; Yamaguchi, Kikuo; Iriguchi, Norio; Ueno, Shoogo

    2003-05-01

    Conductivity tensor images of the rat brain were obtained by a method based on diffusion-weighted magnetic resonance imaging (MRI). Diffusion-weighted images were acquired by a 4.7 T MRI system with motion probing gradients (MPGs) applied in three directions. Conductivities in each MPG direction were calculated from the fast component of the apparent diffusion coefficient and the fraction of the fast component, and two-dimensional conductivity tensor was estimated. Regions of interest (ROIs) were selected in the cortex and the corpus callosum. The mean conductivities in each ROI were 0.014 S/m and 0.018 S/m, respectively. The corpus callosum exhibited higher conductivity anisotropy resulting from anisotropic tissue structures such as axons and dendrites.

  3. Development and evaluation of a soft wearable weight support device for reducing muscle fatigue on shoulder

    PubMed Central

    Cho, Kyu-Jin

    2017-01-01

    Compensating the weight of human limbs is important in reducing muscle fatigue experienced by manual laborers. In this study, a compact and lightweight soft wearable weight support device was developed and evaluated. The device supports gravitational force on the shoulder at any arm posture, although there are some limitations in its assistive performance. The device actuator consists of a cam-rod structure, a tendon-driven mechanism, and a rubber band. The desired assistive torque is translated to the shoulder joint along a tendon routing structure. Device performance was evaluated by measuring muscle activation in with-assist and without-assist conditions. Muscle activation on the deltoid was measured by surface electromyography. An experimental protocol consisting of a series of exercises was executed with six healthy subjects. The subjects raised and lowered their arm from 0 to 100 degrees for 30 times under eight conditions, which were combined with-assist and without-assist conditions, and holding the horizontal angle of the arm at 0, 30, 60, or 90 degrees against the sagittal plane. Surface electromyography data were pre-processed and analyzed using a root mean square method. When muscle fatigue occurs, the root mean square of the surface electromyography increases nonlinearly. This was calculated using the standard deviation of the root mean square. Three of six subjects showed decreased variation of the root mean square between the exercises in the with-assist condition. One subject’s result was significantly reduced (by about 57.6%) in the with-assist condition. In contrast, two subjects did not show significant difference between measurements taken in the with-assist and without-assist conditions. One subject was dropped from the experiment because the device did not fit the subject’s body. In conclusion, the effectiveness of the soft wearable weight support device in supporting shoulder movements was verified through the decreased variation of

  4. [Evidence of social support as therapy for weight loss: a systematic review].

    PubMed

    Flores-Gómez, I; Bacardí-Gascón, M; Armendáriz-Anguiano, A L; Pérez-Morales, M E; Jiménez-Cruz, A

    2012-01-01

    Social Support (SS) therapy can be an effective method of weight loss compared with conventional treatment (CT). To evaluate RCT's using SS therapy on weight in subjects with overweight or obesity. We reviewed all original articles published in MEDLINE/PubMed, SciELO, EBSCO, Google Scholar, from 2000 to August 2011, and one referred in a previous metanalisis, of RCT's of the effect of SS therapy on weight loss, with at least five months of treatment, compared with another therapy or a CT. Eight articles were analyzed. It was observed heterogeneity in the design, differences in the components of the interventions, and cultural characteristics of the population. The difference between groups in weight loss in five out of seven studies, ranged from 2.3 kg (24 m) to 8.3 kg (12 m). However, the treatment in the control groups did not meet the accepted recommended guidelines. There was no allocation concealment in two studies, and no blindness in four. Most studies showed large dispersion in the results. Therefore, the quality of the evidence is low. These results warrant further and better design and longer term studies to generate higher quality evidence.

  5. sw-SVM: sensor weighting support vector machines for EEG-based brain-computer interfaces.

    PubMed

    Jrad, N; Congedo, M; Phlypo, R; Rousseau, S; Flamary, R; Yger, F; Rakotomamonjy, A

    2011-10-01

    In many machine learning applications, like brain-computer interfaces (BCI), high-dimensional sensor array data are available. Sensor measurements are often highly correlated and signal-to-noise ratio is not homogeneously spread across sensors. Thus, collected data are highly variable and discrimination tasks are challenging. In this work, we focus on sensor weighting as an efficient tool to improve the classification procedure. We present an approach integrating sensor weighting in the classification framework. Sensor weights are considered as hyper-parameters to be learned by a support vector machine (SVM). The resulting sensor weighting SVM (sw-SVM) is designed to satisfy a margin criterion, that is, the generalization error. Experimental studies on two data sets are presented, a P300 data set and an error-related potential (ErrP) data set. For the P300 data set (BCI competition III), for which a large number of trials is available, the sw-SVM proves to perform equivalently with respect to the ensemble SVM strategy that won the competition. For the ErrP data set, for which a small number of trials are available, the sw-SVM shows superior performances as compared to three state-of-the art approaches. Results suggest that the sw-SVM promises to be useful in event-related potentials classification, even with a small number of training trials.

  6. Development of a compact, sealless, tripod supported, magnetically driven centrifugal blood pump.

    PubMed

    Yuhki, A; Nogawa, M; Takatani, S

    2000-06-01

    In this study, a tripod supported sealless centrifugal blood pump was designed and fabricated for implantable application using a specially designed DC brushless motor. The tripod structure consists of 3 ceramic balls mounted at the bottom surface of the impeller moving in a polyethylene groove incorporated at the bottom pump casing. The follower magnet inside the impeller is coupled to the driver magnet of the motor outside the bottom pump casing, thus allowing the impeller to slide-rotate in the polyethylene groove as the motor turns. The pump driver has a weight of 230 g and a diameter of 60 mm. The acrylic pump housing has a weight of 220 g with the priming volume of 25 ml. At the pump rpm of 1,000 to 2,200, the generated head pressure ranged from 30 to 150 mm Hg with the maximum system efficiency being 12%. When the prototype pump was used in the pulsatile mock loop to assist the ventricle from its apex to the aorta, a strong correlation was obtained between the motor current and bypass flow waveforms. The waveform deformation index (WDI), defined as the ratio of the fundamental to the higher order harmonics of the motor current power spectral density, was computed to possibly detect the suction occurring inside the ventricle due to the prototype centrifugal pump. When the WDI was kept under the value of 0.20 by adjusting the motor rpm, it was successful in suppressing the suction due to the centrifugal pump in the ventricle. The prototype sealless, centrifugal pump together with the control method based on the motor current waveform analysis may offer an intermediate support of the failing left or right ventricle bridging to heart transplantation.

  7. The influence of family, friend, and coworker social support and social undermining on weight gain prevention among adults

    PubMed Central

    Wang, Monica L.; Pbert, Lori; Lemon, Stephenie C.

    2014-01-01

    Objective Examine longitudinal associations between sources of social support and social undermining for healthy eating and physical activity and weight change. Design and Methods Data are from 633 employed adults participating in a cluster-randomized multilevel weight gain prevention intervention. Primary predictors included social support and social undermining for two types of behaviors (healthy eating and physical activity) from three sources (family, friends, and coworkers) obtained via self-administered surveys. The primary outcome (weight in kg) was measured by trained staff. Data were collected at baseline, 12 months, and 24 months. Linear multivariable models examined the association of support and social undermining with weight over time, adjusting for intervention status, time, gender, age, education, and clustering of individuals within schools. Results Adjusting for all primary predictors and covariates, friend support for healthy eating (β=−0.15), coworker support for healthy eating (β=−0.11), and family support for physical activity (β=−0.032) were associated with weight reduction at 24 months (p-values<0.05). Family social undermining for healthy eating was associated with weight gain at 24 months (β=0.12; p=0.0019). Conclusions Among adult employees, friend and coworker support for healthy eating and family support for physical activity predicted improved weight management. Interventions that help adults navigate family social undermining of healthy eating are warranted. PMID:24942930

  8. Influence of family, friend and coworker social support and social undermining on weight gain prevention among adults.

    PubMed

    Wang, Monica L; Pbert, Lori; Lemon, Stephenie C

    2014-09-01

    Examine longitudinal associations between sources of social support and social undermining for healthy eating and physical activity and weight change. Data are from 633 employed adults participating in a cluster-randomized multilevel weight gain prevention intervention. Primary predictors included social support and social undermining for two types of behaviors (healthy eating and physical activity) from three sources (family, friends, and coworkers) obtained via self-administered surveys. The primary outcome (weight in kg) was measured by trained staff. Data were collected at baseline, 12 months, and 24 months. Linear multivariable models examined the association of support and social undermining with weight over time, adjusting for intervention status, time, gender, age, education, and clustering of individuals within schools. Adjusting for all primary predictors and covariates, friend support for healthy eating (β = -0.15), coworker support for healthy eating (β = -0.11), and family support for physical activity (β = -0.032) were associated with weight reduction at 24 months (P-values<0.05). Family social undermining for healthy eating was associated with weight gain at 24 months (β = 0.12; P = 0.0019). Among adult employees, friend and coworker support for healthy eating and family support for physical activity predicted improved weight management. Interventions that help adults navigate family social undermining of healthy eating are warranted. © 2014 The Obesity Society.

  9. Stability of polyelectrolyte-coated iron nanoparticles for T2-weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    McGrath, Andrew J.; Dolan, Ciaran; Cheong, Soshan; Herman, David A. J.; Naysmith, Briar; Zong, Fangrong; Galvosas, Petrik; Farrand, Kathryn J.; Hermans, Ian F.; Brimble, Margaret; Williams, David E.; Jin, Jianyong; Tilley, Richard D.

    2017-10-01

    Iron nanoparticles are highly-effective magnetic nanoparticles for T2 magnetic resonance imaging (MRI). However, the stability of their magnetic properties is dependent on good protection of the iron core from oxidation in aqueous media. Here we report the synthesis of custom-synthesized phosphonate-grafted polyelectrolytes (PolyM3) of various chain lengths, for efficient coating of iron nanoparticles with a native iron oxide shell. The size of the nanoparticle-polyelectrolyte assemblies was investigated by transmission electron microscopy and dynamic light scattering, while surface attachment was confirmed by Fourier transform infrared spectroscopy. Low cytotoxicity was observed for each of the nanoparticle-polyelectrolyte (;Fe-PolyM3;) assemblies, with good cell viability (>80%) remaining up to 100 μg mL-1 Fe in HeLa cells. When applied in T2-weighted MRI, corresponding T2 relaxivities (r2) of the Fe-PolyM3 assemblies were found to be dependent on the chain length of the polyelectrolyte. A significant increase in contrast was observed when polyelectrolyte chain length was increased from 6 to 65 repeating units, implying a critical chain length required for stabilization of the α-Fe nanoparticle core.

  10. Weight support and balance during perturbed stance in the chronic spinal cat.

    PubMed

    Macpherson, J M; Fung, J

    1999-12-01

    The intact cat maintains balance during unexpected disturbances of stance through automatic postural responses that are stereotyped and rapid. The extent to which the chronic spinal cat can maintain balance during stance is unclear, and there have been no quantitative studies that examined this question directly. This study examined whether the isolated lumbosacral cord of the chronic spinal cat can generate automatic postural responses in the hindlimbs during translation of the support surface. Responses to 16 directions of linear translation in the horizontal plane were quantified before and after spinalization at the T(6) level in terms of forces exerted by each paw against the support, motion of the body segments (kinematics), and electromyographic (EMG) activity. After spinalization, the cats were trained on a daily basis to stand on the force platform, and all four cats were able to support their full body weight. The cats usually required assistance for balance or stability in the horizontal plane, which was provided by an experimenter exerting gentle lateral force at the level of the hips. Three of the four animals could maintain independent stance for a brief period (10 s) after the experimenter stabilized them. The fourth cat maintained weight support but always required assistance with balance. Perturbations were delivered during the periods of independent stance in three cats and during assisted stance in the fourth. A response to translation in the spinal cats was observed only in those muscles that were tonically active to maintain stance and never in the flexors. Moreover, latencies were increased and amplitudes of activation were diminished compared with control. Nevertheless, flexors and extensors were recruited easily during behaviors such as paw shake and stepping. It is concluded that centers above the lumbosacral cord are required for the full elaboration of automatic postural responses. Although the spinal cat can achieve good weight support

  11. Sensitivity of joint moments to changes in walking speed and body-weight-support are interdependent and vary across joints.

    PubMed

    Goldberg, Saryn R; Stanhope, Steven J

    2013-04-05

    We investigated the effect of simultaneous changes in body-weight-support level and walking speed on mean peak internal joint moments at the ankle, knee and hip. We hypothesized that observed changes in these joint moments would be approximately linear with both body-weight-support and walking speed and would be similar across joints. Kinematic and kinetic data were collected from 8 unimpaired adult subjects walking on an instrumented treadmill while wearing a dynamically controlled overhead support harness. Subjects walked with four levels of body-weight-support (0%, 20%, 40%, and 60% of bodyweight) at three walking speeds (0.4, 0.6, and 0.8 statures/s, ranging on average from 0.7 to 1.4m/s). Data were used to calculate mean peak joint moments across subjects for each condition. In general, subjects' mean peak joint moments decreased linearly with decreasing walking speed and with increasing body-weight-support, except the knee extension moment, which showed a quadratic relationship with walking speed and no significant change with body-weight-support. All joint moments, with the exception of knee extension, showed a significant interaction effect between walking speed and body-weight-support, indicating that the sensitivity of these joint moments to changes in these variables was interdependent. In most cases, the ankle and hip extension moments showed the largest sensitivity to walking speed. The ankle moment was observed to have the greatest sensitivity to body-weight-support. This finding, that altering walking speed and body-weight-support level results in non-uniform changes in peak moments across joints, suggests that further research is warranted to establish the set of combined speed and support conditions that produce motor patterns supportive of normal gait retraining. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Clinical utility of diffusion-weighted magnetic resonance imaging in the assessment of ischemic stroke.

    PubMed

    Lutsep, H L; Albers, G W; DeCrespigny, A; Kamat, G N; Marks, M P; Moseley, M E

    1997-05-01

    Diffusion-weighted imaging (DWI) detects small changes in water diffusion that occur in ischemic brain. This study evaluated the clinical usefulness of a phase-navigated spin-echo DWI sequence compared with T2-weighted magnetic resonance imaging (T2W MRI) in patients with cerebral ischemia and assessed apparent diffusion coefficient (ADC) and T2-weighted imaging (T2WI) changes over time. ADC values and T2 ratios of image intensity were measured from the region of ischemia and from the corresponding contralateral brain region. The clinical histories of patients with DWI scans obtained over the course of 1 year were reviewed to ascertain whether DWI aided in clinical diagnosis or management. Of 103 scans obtained a mean of 10.4 days after symptom onset, DWI detected six lesions not seen on T2WI and discriminated two new infarcts from old lesions. DWI was most useful within 48 hours of the ictus. The evolution of ADC values and T2 ratios was evaluated in 26 cases with known symptom onset times. ADC values were low at less than 1 week after stroke onset and became elevated at chronic time points. T2 ratios were near normal acutely, increasing thereafter. DWI was superior to T2W MRI in detecting acute stroke, whereas both techniques assisted in determining lesion age.

  13. Spot Sign in Acute Intracerebral Hemorrhage in Dynamic T1-Weighted Magnetic Resonance Imaging.

    PubMed

    Schindlbeck, Katharina A; Santaella, Anna; Galinovic, Ivana; Krause, Thomas; Rocco, Andrea; Nolte, Christian H; Villringer, Kersten; Fiebach, Jochen B

    2016-02-01

    In computed tomographic imaging of acute intracerebral hemorrhage spot sign on computed tomographic angiography has been established as a marker for hematoma expansion and poor clinical outcome. Although, magnetic resonance imaging (MRI) can accurately visualize acute intracerebral hemorrhage, a corresponding MRI marker is lacking to date. We prospectively examined 50 consecutive patients with acute intracerebral hemorrhage within 24 hours of symptom onset. The MRI protocol consisted of a standard stroke protocol and dynamic contrast-enhanced T1-weighted imaging with a time resolution of 7.07 s/batch. Stroke scores were assessed at admission and at time of discharge. Volume measurements of hematoma size and spot sign were performed with MRIcron. Contrast extravasation within sites of the hemorrhage (MRI spot sign) was seen in 46% of the patients. Patients with an MRI spot sign had a significantly shorter time to imaging than those without (P<0.001). The clinical outcome measured by the modified Rankin Scale was significantly worse in patients with spot sign compared with those without (P≤0.001). Hematoma expansion was observed in the spot sign group compared with the nonspot sign group, although the differences were not significant. Spot sign can be detected using MRI on postcontrast T1-weighted and dynamic T1-weighted images. It is associated with worse clinical outcome. The time course of contrast extravasation in dynamic T1 images indicates that these spots represent ongoing bleeding. © 2015 American Heart Association, Inc.

  14. Predicting Weight Support Based on Wake Measurements of a Flying Bird in Still Air

    NASA Astrophysics Data System (ADS)

    Gutierrez, Eric; Lentink, David

    2014-11-01

    The wake development of a freely flying Pacific Parrotlet (Forpus coelestis) was examined in still air. The bird was trained to fly from perch to perch through the laser sheet while wearing custom-made laser safety goggles. This enabled a detailed study of the evolution of the vortices shed in its wake using high-speed particle image velocimetry at 1000 Hz in the plane transverse to the flight path. The measurement started when the bird was approximately 0.25 wingbeats in front of the laser sheet and stopped after it traveled 3.5 wingbeats beyond the laser sheet. The instantaneous lift force that supports body weight was calculated based on the velocity field, using both the Kuttta-Joukowski and the actuator disk quasi-steady model. During the first few flaps, both models predict an instantaneous lift that is reasonably close to the weight of the bird. Several flaps away from the laser sheet, however, the models predict that the lift steadily declines to about 50% of the weight of the bird. In contrast to earlier reports for bat wakes in wind tunnels, these findings for bird wakes in still air suggest that the predictive strength of quasi-steady force calculations depends on the distance between the animal and the laser sheet.

  15. Boosting specificity of MEG artifact removal by weighted support vector machine.

    PubMed

    Duan, Fang; Phothisonothai, Montri; Kikuchi, Mitsuru; Yoshimura, Yuko; Minabe, Yoshio; Watanabe, Kastumi; Aihara, Kazuyuki

    2013-01-01

    An automatic artifact removal method of magnetoencephalogram (MEG) was presented in this paper. The method proposed is based on independent components analysis (ICA) and support vector machine (SVM). However, different from the previous studies, in this paper we consider two factors which would influence the performance. First, the imbalance factor of independent components (ICs) of MEG is handled by weighted SVM. Second, instead of simply setting a fixed weight to each class, a re-weighting scheme is used for the preservation of useful MEG ICs. Experimental results on manually marked MEG dataset showed that the method proposed could correctly distinguish the artifacts from the MEG ICs. Meanwhile, 99.72% ± 0.67 of MEG ICs were preserved. The classification accuracy was 97.91% ± 1.39. In addition, it was found that this method was not sensitive to individual differences. The cross validation (leave-one-subject-out) results showed an averaged accuracy of 97.41% ± 2.14.

  16. In vivo measurement of aerodynamic weight support in freely flying birds

    NASA Astrophysics Data System (ADS)

    Lentink, David; Haselsteiner, Andreas; Ingersoll, Rivers

    2014-11-01

    Birds dynamically change the shape of their wing during the stroke to support their body weight aerodynamically. The wing is partially folded during the upstroke, which suggests that the upstroke of birds might not actively contribute to aerodynamic force production. This hypothesis is supported by the significant mass difference between the large pectoralis muscle that powers the down-stroke and the much smaller supracoracoideus that drives the upstroke. Previous works used indirect or incomplete techniques to measure the total force generated by bird wings ranging from muscle force, airflow, wing surface pressure, to detailed kinematics measurements coupled with bird mass-distribution models to derive net force through second derivatives. We have validated a new method that measures aerodynamic force in vivo time-resolved directly in freely flying birds which can resolve this question. The validation of the method, using independent force measurements on a quadcopter with pulsating thrust, show the aerodynamic force and impulse are measured within 2% accuracy and time-resolved. We demonstrate results for quad-copters and birds of similar weight and size. The method is scalable and can be applied to both engineered and natural flyers across taxa. The first author invented the method, the second and third authors validated the method and present results for quadcopters and birds.

  17. Vibration study of the APS storage ring 0.8 meter quadrupole magnet/magnet support assembly

    SciTech Connect

    Jendrzejczyk, J.A.; Wambsganss, M.W.; Smith, R.K.

    1991-06-01

    The objectives of this study are as follows: Determine the vibration characteristics (frequency, damping, and mode shapes) of the magnet on prototypic supports (the actual mounting system used to mount the magnet on the girder). Measure system response to ambient floor motion. Measure the effect of various modifications to determine if the magnet response can be modified to minimize unwanted response characteristics. Modifications investigated include support schemes, increasing system damping, and increasing mechanical rigidity. Measure system response to coolant flow. Determine vibrational characteristics of a large concrete block placed on a concrete floor, including response to ambient floor motions.

  18. Effects of training and weight support on muscle activation in Parkinson's disease.

    PubMed

    Rose, Martin H; Løkkegaard, Annemette; Sonne-Holm, Stig; Jensen, Bente R

    2013-12-01

    The aim of this study was to investigate the effect of high-intensity locomotor training on knee extensor and flexor muscle activation and adaptability to increased body-weight (BW) support during walking in patients with Parkinson's disease (PD). Thirteen male patients with idiopathic PD and eight healthy participants were included. The PD patients completed an 8-week training program on a lower-body, positive-pressure treadmill. Knee extensor and flexor muscles activation during steady treadmill walking (3 km/h) were measured before, at the mid-point, and after training. Increasing BW support decreased knee extensor muscle activation (normalization) and increased knee flexor muscle activation (abnormal) in PD patients when compared to healthy participants. Training improved flexor peak muscle activation adaptability to increased (BW) support during walking in PD patients. During walking without BW support shorter knee extensor muscle off-activation time and increased relative peak muscle activation was observed in PD patients and did not improve with 8 weeks of training. In conclusion, patients with PD walked with excessive activation of the knee extensor and flexor muscles when compared to healthy participants. Specialized locomotor training may facilitate adaptive processes related to motor control of walking in PD patients.

  19. Effects of competing news media frames of weight on antifat stigma, beliefs about weight and support for obesity-related public policies.

    PubMed

    Frederick, D A; Saguy, A C; Sandhu, G; Mann, T

    2016-03-01

    In the popular news media, public health officials routinely emphasize the health risks of obesity and portray weight as under personal control. These messages may increase support for policies designed to reduce rates of obesity, but can also increase antifat stigma. Less often, the media cover 'Health at Every Size' or 'Fat Rights' perspectives that may have the opposite effects. We investigated how exposure to different 'fat frames' shifts attitudes about weight and support for obesity policies. Across four experiments (n=2187), people read constructed news articles framing fatness as negative (unhealthy, controllable, acceptable to stigmatize) or positive (healthy, uncontrollable, unacceptable to stigmatize). Compared with people who read fat-positive frames, people who read fat-negative frames expressed more: belief in the health risks of being fat (d=0.95-1.22), belief weight is controllable (d=0.38-0.55), support for charging obese people more for health insurance (d=0.26-0.77), antifat prejudice (in three out of four experiments, d=0.28-0.39), willingness to discriminate against fat people (d=0.39-0.71) and less willingness to celebrate body size diversity (d=0.37-0.64). They were also less willing to say that women at the lower end of the obese range could be healthy at their weights. Effects on support for public policies, however, were generally small and/or nonsignificant. Compared with a control condition, exposure to fat-positive frames generally shifted attitudes more than fat-negative frames. In experiment 4, adding a message about the unacceptability of weight-based discrimination to unhealthy/controllable news articles only reduced antifat stigma on one of three measures compared with articles adding a discrimination-acceptable message. Exposure to different news frames of fat can shift beliefs about weight-related health risks and weight-based stigma. Shifting policy attitudes, however, is more challenging.

  20. Lumbar stenosis rates in symptomatic patients using weight-bearing and recumbent magnetic resonance imaging.

    PubMed

    Gilbert, John W; Martin, J Chad; Wheeler, Greg R; Storey, Benjamin B; Mick, Gregory E; Richardson, Gay B; Herder, Stephanie L; Gyarteng-Dakwa, Kwadwo

    2011-10-01

    The purpose of this study was to determine the rate of lumbar stenosis detected via magnetic resonance imaging (MRI) in patients with symptomatic foraminal stenosis, lateral recess stenosis, or central stenosis. A retrospective review was performed on 1983 MRI scans from a 2-year period on 1486 symptomatic patients. Of these patients, 761 were scanned in the recumbent position using low-field (0.3 T, Airis II; Hitachi, Twinsburg, Ohio) MRI, and 725 were scanned in an upright sitting position using midfield (0.6 T) open Upright MRI (Fonar Corp, Melville, NY). In total, 986 serial scans (recumbent) and 997 serial scans (weight-bearing) were performed. Of scans performed in the recumbent position, stenoses were identified in 382 scans (38.8%), central stenosis in 119 scans (12%), lateral recess stenosis in 91 scans (9.2%), and foraminal stenosis in 327 scans (33.2%). Of scans performed in a weight-bearing position, stenoses were identified in 565 scans (56.7%), central stenosis in 136 scans (13.6%), lateral recess stenosis in 206 scans (20.7%), and foraminal stenosis in 524 scans (52.6%). The stenosis rates as indicated by MRI interpretation ranged between 38.5% (recumbent) and 56.7% (weight-bearing). These rates are higher than those reported in the medical literature for asymptomatic patients. Further study is needed to determine whether weight-bearing, compared with recumbent, MRI better informs the clinician in the diagnosis of spinal stenosis. Copyright © 2011 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  1. Diffusion-weighted magnetic resonance imaging in monitoring rectal cancer response to neoadjuvant chemoradiotherapy.

    PubMed

    Barbaro, Brunella; Vitale, Renata; Valentini, Vincenzo; Illuminati, Sonia; Vecchio, Fabio M; Rizzo, Gianluca; Gambacorta, Maria Antonietta; Coco, Claudio; Crucitti, Antonio; Persiani, Roberto; Sofo, Luigi; Bonomo, Lorenzo

    2012-06-01

    To prospectively monitor the response in patients with locally advanced nonmucinous rectal cancer after chemoradiotherapy (CRT) using diffusion-weighted magnetic resonance imaging. The histopathologic finding was the reference standard. The institutional review board approved the present study. A total of 62 patients (43 men and 19 women; mean age, 64 years; range, 28-83) provided informed consent. T(2)- and diffusion-weighted magnetic resonance imaging scans (b value, 0 and 1,000 mm(2)/s) were acquired before, during (mean 12 days), and 6-8 weeks after CRT. We compared the median apparent diffusion coefficients (ADCs) between responders and nonresponders and examined the associations with the Mandard tumor regression grade (TRG). The postoperative nodal status (ypN) was evaluated. The Mann-Whitney/Wilcoxon two-sample test was used to evaluate the relationships among the pretherapy ADCs, extramural vascular invasion, early percentage of increases in ADCs, and preoperative ADCs. Low pretreatment ADCs (<1.0 × 10(-3)mm(2)/s) were correlated with TRG 4 scores (p = .0011) and associated to extramural vascular invasion with ypN+ (85.7% positive predictive value for ypN+). During treatment, the mean percentage of increase in tumor ADC was significantly greater in the responders than in the nonresponders (p < .0001) and a >23% ADC increase had a 96.3% negative predictive value for TRG 4. In 9 of 16 complete responders, CRT-related tumor downsizing prevented ADC evaluations. The preoperative ADCs were significantly different (p = .0012) between the patients with and without downstaging (preoperative ADC ≥1.4 × 10(-3)mm(2)/s showed a positive and negative predictive value of 78.9% and 61.8%, respectively, for response assessment). The TRG 1 and TRG 2-4 groups were not significantly different. Diffusion-weighted magnetic resonance imaging seems to be a promising tool for monitoring the response to CRT. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Diffusion-Weighted Magnetic Resonance Imaging in Monitoring Rectal Cancer Response to Neoadjuvant Chemoradiotherapy

    SciTech Connect

    Barbaro, Brunella; Vitale, Renata; Valentini, Vincenzo; Illuminati, Sonia; Vecchio, Fabio M.; Rizzo, Gianluca; Gambacorta, Maria Antonietta; Coco, Claudio; Crucitti, Antonio; Persiani, Roberto; Sofo, Luigi; Bonomo, Lorenzo

    2012-06-01

    Purpose: To prospectively monitor the response in patients with locally advanced nonmucinous rectal cancer after chemoradiotherapy (CRT) using diffusion-weighted magnetic resonance imaging. The histopathologic finding was the reference standard. Methods and Materials: The institutional review board approved the present study. A total of 62 patients (43 men and 19 women; mean age, 64 years; range, 28-83) provided informed consent. T{sub 2}- and diffusion-weighted magnetic resonance imaging scans (b value, 0 and 1,000 mm{sup 2}/s) were acquired before, during (mean 12 days), and 6-8 weeks after CRT. We compared the median apparent diffusion coefficients (ADCs) between responders and nonresponders and examined the associations with the Mandard tumor regression grade (TRG). The postoperative nodal status (ypN) was evaluated. The Mann-Whitney/Wilcoxon two-sample test was used to evaluate the relationships among the pretherapy ADCs, extramural vascular invasion, early percentage of increases in ADCs, and preoperative ADCs. Results: Low pretreatment ADCs (<1.0 Multiplication-Sign 10{sup -3}mm{sup 2}/s) were correlated with TRG 4 scores (p = .0011) and associated to extramural vascular invasion with ypN+ (85.7% positive predictive value for ypN+). During treatment, the mean percentage of increase in tumor ADC was significantly greater in the responders than in the nonresponders (p < .0001) and a >23% ADC increase had a 96.3% negative predictive value for TRG 4. In 9 of 16 complete responders, CRT-related tumor downsizing prevented ADC evaluations. The preoperative ADCs were significantly different (p = .0012) between the patients with and without downstaging (preoperative ADC {>=}1.4 Multiplication-Sign 10{sup -3}mm{sup 2}/s showed a positive and negative predictive value of 78.9% and 61.8%, respectively, for response assessment). The TRG 1 and TRG 2-4 groups were not significantly different. Conclusion: Diffusion-weighted magnetic resonance imaging seems to be a promising

  3. People trying to lose weight dislike calorie counting apps and want motivational support to help them achieve their goals.

    PubMed

    Solbrig, Linda; Jones, Ray; Kavanagh, David; May, Jon; Parkin, Tracey; Andrade, Jackie

    2017-03-01

    Two thirds of UK adults are overweight or obese and at increased risk of chronic conditions such as heart disease, diabetes and certain cancers. Basic public health support for weight loss comprises information about healthy eating and lifestyle, but internet and mobile applications (apps) create possibilities for providing long-term motivational support. To explore among people currently trying to lose weight, or maintaining weight loss, (i) problems, experiences and wishes in regards to weight management and weight loss support including e-health support; (ii) reactions to Functional Imagery Training (FIT) as a possible intervention. Six focus groups (N = 24 in total) were recruited from a public pool of people who had expressed an interest in helping with research. The topics considered were barriers to weight loss, desired support for weight loss and acceptability of FIT including the FIT app. The focus group discussions were transcribed and thematically analysed. All groups spontaneously raised the issue of waning motivation and expressed the desire for motivational app support for losing weight and increasing physical activity. They disliked calorie counting apps and those that required lots of user input. All groups wanted behavioural elements such as setting and reviewing goals to be included, with the ability to personalise the app by adding picture reminders and choosing times for goal reminders. Participants were positive about FIT and FIT support materials. There is a mismatch between the help provided via public health information campaigns and commercially available weight-loss self-help (lifestyle information, self-monitoring), and the help that individuals actually desire (motivational and autonomous e-support), posing an opportunity to develop more effective electronic, theory-driven, motivational, self-help interventions.

  4. Diffusion-weighted magnetic resonance imaging in patients with prostate cancer treated with radiotherapy.

    PubMed

    Iannelli, Giancarlo; Caivano, Rocchina; Rago, Luciana; Simeon, Vittorio; Lotumolo, Antonella; Rabasco, Paola; Villonio, Antonio; Gioioso, Matilde; Mastrangelo, Pietro; Barchetti, Flavio; Panebianco, Valeria; Macarini, Luca; Guglielmi, Giuseppe; Cammarota, Aldo

    2016-01-01

    To evaluate the utility of a multiparametric 3T magnetic resonance imaging (MRI) study using diffusion-weighted images (DWI) for the assessment of prostate cancer before and after radiotherapy (RT). A total of 34 patients, who received a histologic diagnosis of prostate adenocarcinoma, underwent MRI examination before and after local RT for the assessment of response to treatment. Apparent diffusion coefficient (ADC) values were calculated and compared. Before RT, DWI shows pathologic restriction of signal, while after RT pathologic restriction of signal was reduced or disappeared. The ADC values were significantly increased after therapy (p<0.05). The use of DWI with ADC measurements may be an imaging biomarker in the assessment of prostate cancer.

  5. Eu, Gd-Codoped Yttria Nanoprobes for Optical and T₁-Weighted Magnetic Resonance Imaging.

    PubMed

    Atabaev, Timur Sh; Lee, Jong Ho; Shin, Yong Cheol; Han, Dong-Wook; Choo, Ki Seok; Jeon, Ung Bae; Hwang, Jae Yeon; Yeom, Jeong A; Kim, Hyung-Kook; Hwang, Yoon-Hwae

    2017-02-10

    Nanoprobes with multimodal functionality have attracted significant interest recently because of their potential applications in nanomedicine. This paper reports the successful development of lanthanide-doped Y₂O₃ nanoprobes for potential applications in optical and magnetic resonance (MR) imaging. The morphology, structural, and optical properties of these nanoprobes were characterized by transmission electron microscope (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and photoluminescence (PL). The cytotoxicity test showed that the prepared lanthanide-doped Y₂O₃ nanoprobes have good biocompatibility. The obvious contrast enhancement in the T₁-weighted MR images suggested that these nanoprobes can be used as a positive contrast agent in MRI. In addition, the clear fluorescence images of the L-929 cells incubated with the nanoprobes highlight their potential for optical imaging. Overall, these results suggest that prepared lanthanide-doped Y₂O₃ nanoprobes can be used for simultaneous optical and MR imaging.

  6. Fahr disease: use of susceptibility-weighted imaging for diagnostic dilemma with magnetic resonance imaging

    PubMed Central

    Solak, Aynur; Genc, Berhan; Kulu, Ugur

    2015-01-01

    Fahr disease (FD) is a well-defined rare neurodegenerative disease that is characterized by idiopathic bilateral symmetric extensive striopallidodentate calcifications. The patients may present with diverse manifestations, most commonly movement disorder, cognitive impairment, and ataxia. Computed tomography (CT) is considered to be critical for accurate diagnosis because it is difficult to reliably identify calcifications by routine magnetic resonance imaging (MRI). Susceptibility-weighted imaging (SWI) is a relatively new 3D gradient-echo (GE) MR sequence with special phase and magnitude processing. SWI phase images can recognize calcifications definitively with higher sensitivity compared to other MRI sequences. In this article, we present two cases of FD with different manifestations and neuroimaging in different age groups and genders, which were diagnosed by SWI and confirmed with CT, and we discuss the contribution of SWI in the diagnosis of FD. In conclusion, we suggest integrating SWI with MRI protocol to identify calcifications in suspicion of neurodegenerative disorders. PMID:26435928

  7. Fahr disease: use of susceptibility-weighted imaging for diagnostic dilemma with magnetic resonance imaging.

    PubMed

    Sahin, Neslin; Solak, Aynur; Genc, Berhan; Kulu, Ugur

    2015-08-01

    Fahr disease (FD) is a well-defined rare neurodegenerative disease that is characterized by idiopathic bilateral symmetric extensive striopallidodentate calcifications. The patients may present with diverse manifestations, most commonly movement disorder, cognitive impairment, and ataxia. Computed tomography (CT) is considered to be critical for accurate diagnosis because it is difficult to reliably identify calcifications by routine magnetic resonance imaging (MRI). Susceptibility-weighted imaging (SWI) is a relatively new 3D gradient-echo (GE) MR sequence with special phase and magnitude processing. SWI phase images can recognize calcifications definitively with higher sensitivity compared to other MRI sequences. In this article, we present two cases of FD with different manifestations and neuroimaging in different age groups and genders, which were diagnosed by SWI and confirmed with CT, and we discuss the contribution of SWI in the diagnosis of FD. In conclusion, we suggest integrating SWI with MRI protocol to identify calcifications in suspicion of neurodegenerative disorders.

  8. Brain Magnetic Resonance with Negative Diffusion-Weighted Imaging: Does It Preclude Acute Stroke Diagnosis?

    PubMed

    Aragão Homem, Catarina; Fonseca, Ana Catarina; Geraldes, Ruth; Pinho e Melo, Teresa

    2015-09-01

    Brain magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) sequences and correlative apparent diffusion coefficient (ADC) maps is a very sensitive way to detect acute ischemic stroke. Cases of negative MRI-DWI on acute phase of ischemic stroke are uncommon, and most of them are reported in single small-sized lesions, which in most cases are below the technical spatial resolution and in patients imaged shortly after the symptoms start. The few published cases of territorial ischemic stroke with negative DWI affect exclusively one vascular territory. We report the case of an ischemic stroke involving 2 different arteries of the posterior circulation, with a negative DWI/ADC brain MRI 18 hours after time-last-seen-well. We also suggest a possible explanation regarding the mechanism of false-negative diffusion MRI on ischemic stroke. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  9. Diffusion weighted imaging and apparent diffusion coefficient in 3 tesla magnetic resonance imaging of breast lesions.

    PubMed

    Caivano, Rocchina; Villonio, Antonio; D' Antuono, Felice; Gioioso, Matilde; Rabasco, Paola; Iannelli, Giancarlo; Zandolino, Alexis; Lotumolo, Antonella; Dinardo, Giuseppina; Macarini, Luca; Guglielmi, Giuseppe; Cammarota, Aldo

    2015-05-01

    To evaluate the utility of diffusion-weighted-imaging (DWI) and apparent-diffusion-coefficient (ADC) in a 3T magnetic-resonance-imaging (MRI) study of breast cancer. In particular, the study aims to classify ADC-values according to histology either for benign or malignant lesions. 110 Breast MRI with MRI-DWI sequences and quantitative evaluation of the ADC were retrospectively reviewed. Results obtained with MRI-DWI and with biopsy were analyzed and ADC values were compared to histological results. MRI showed a 95.5% sensitivity and a 83.7% specificity. The mean ADC values of benign and malignant lesions were 2.06 ± 0.19 and 1.03 ± 0.07 mm(2)/s, respectively (p < .05). DWI and ADC-values could help distinguishing malignant and benign breast masses.

  10. A Single-band Cold Mass Support System for the MICE Superconducting Coupling Magnet

    SciTech Connect

    Wu, Hong; Wang, Li; Liu, X.K.; Liu, C.S.; Li, L.K.; Xu, Feng Yu; Jia, Lin X.; Green, Michael A.

    2008-04-02

    The cooling channel of the Muon Ionization Cooling Experiment (MICE) consists of eighteen superconducting solenoid coils, which are magnetically hooked together and contained in seven modules. The operations of a pair of MICE superconducting coupling magnets are affected directly by the other solenoid coils in the MICE channel. In order to meet the stringent requirement for the magnet center and axis azimuthal angle at 4.2 K, a self-centered tension-band cold mass support system with intermediate thermal interruption was applied for the MICE superconducting coupling magnet. The physical center of the magnet does not change as it is cooled down from 300 K to 4.2 K using this support system. This paper analyzed and calculated force loads on the coupling magnet under various operation modes of the MICE cooling channel. The performance parameters of a single-band cold mass support system were calculated also.

  11. Perceived Social Support for Exercise and Weight Loss in Adolescents Undergoing Sleeve Gastrectomy.

    PubMed

    Mackey, Eleanor Race; Olson, Alexandra; Merwin, Stephanie; Wang, Jichuan; Nadler, Evan P

    2017-08-02

    Bariatric surgery is an effective treatment for youth with severe obesity. However, outcomes are variable and there remains sparse understanding of predictors of weight loss following surgery. The current study examines the role of adolescent-reported pre-operative social support around exercise, binge eating, and exercise to predict excess body mass index (EBMI) loss from 3 to 12 months post-surgery. Participants were 101 adolescents ages 12-21 (M age = 16.6, SD = 1.8). Pre-operative body mass index (BMI) ranged from 35 to 87 (M = 50.3, SD = 8.6). Structural equation modeling (SEM) was used to evaluate a model of the association of adolescent report of perceived social support for exercise with less binge eating (items from the Eating Disorder Diagnostic Scale) and more self-reported exercise (items from the Youth Risk Behavior Surveillance System). The model was used to predict EBMI loss at 3, 6, 9, and 12 months post-surgery. Social support significantly predicted exercise and demonstrated a trend for predicting binge eating, such that more social support was associated with more exercise and a trend for less binge eating. Binge eating was associated with less EBMI loss. However, there was no association of exercise with EBMI loss. Pre-operative binge eating should be a target for identification and treatment prior to sleeve gastrectomy in adolescents. Although not directly or indirectly associated with EBMI loss, perceived social support around exercise was associated with increased exercise, which may make it a consideration for a target for intervention as well.

  12. Diffusion-weighted magnetic resonance imaging to predict response of hepatocellular carcinoma to chemoembolization

    PubMed Central

    Chung, Johnathan C; Naik, Neel K; Lewandowski, Robert J; Deng, Jie; Mulcahy, Mary F; Kulik, Laura M; Sato, Kent T; Ryu, Robert K; Salem, Riad; Larson, Andrew C; Omary, Reed A

    2010-01-01

    AIM: To investigate whether intra-procedural diffusion-weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during transcatheter arterial chemoembolization (TACE). METHODS: Sixteen patients (15 male), aged 59 ± 11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable HCC in a hybrid magnetic resonance/interventional radiology suite. Anatomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm2) were performed on a 1.5-T unit. Tumor enhancement and apparent diffusion coefficient (ADC, mm2/s) values were assessed immediately before and at 1 and 3 mo after TACE. We calculated the percent change (PC) in ADC values at all time points. We compared follow-up ADC values to baseline values using a paired t test (α = 0.05). RESULTS: The intra-procedural sensitivity, specificity, and positive and negative predictive values (%) for detecting a complete or partial 1-mo tumor response using ADC PC thresholds of ±5%, ±10%, and ±15% were 77, 67, 91, and 40; 54, 67, 88, and 25; and 46, 100, 100, and 30, respectively. There was no clear predictive value for the 3-mo follow-up. Compared to baseline, the immediate post-procedure and 1-mo mean ADC values both increased; the latter obtaining statistical significance (1.48 ± 0.29 mm2/s vs 1.65 ± 0.35 × 10-3 mm2/s, P < 0.014). CONCLUSION: Intra-procedural ADC changes of > 15% predicted 1-mo anatomical HCC response with the greatest accuracy, and can provide valuable feedback at the time of TACE. PMID:20593501

  13. Training Veterans to Provide Peer Support in a Weight-Management Program: MOVE!

    PubMed Central

    Haynes-Maslow, Lindsey; Carr, Carol; Orr, Melinda; Kahwati, Leila C.; Weiner, Bryan J.; Kinsinger, Linda

    2013-01-01

    Introduction The Veterans Health Administration (VHA) has implemented MOVE!, a weight-management program for veterans designed to address the increasing proportion of overweight and obese veterans. The objective of our study was to determine whether peer support employing motivational interviewing (MI) could positively influence lifestyle changes, thus expanding the reach of the MOVE! program. We describe the initial evaluation of the peer training program. Methods We developed an MI peer counselor training program for volunteer veterans, the “Buddies” program, to provide one-on-one telephone support for veterans enrolled in MOVE!. Buddies were recruited at 5 VHA sites and trained to provide peer support for the 6-month MOVE! intervention. We used a DVD to teach MI skills and followed with 2 to 3 booster sessions. We observed training, conducted pre- and posttraining surveys, and debriefed focus groups to assess training feasibility. Results Fifty-six Buddies were trained. Results indicate positive receipt of the program (89% reported learning about peer counseling and 87% reported learning communication skills). Buddies showed a small improvement in MI self-efficacy on posttraining surveys. We also identified key challenges to learning MI and training implementation. Conclusions MI training is feasible to implement and acceptable to volunteer Buddies. Trainers must assess how effectively volunteers learn MI skills in order to enhance its effective use in health promotion. PMID:24199738

  14. Does Social Support Buffer the Association Between Stress Eating and Weight Gain During the Transition to College? Differences by Gender.

    PubMed

    Darling, Katherine E; Fahrenkamp, Amy J; Wilson, Shana M; Karazsia, Bryan T; Sato, Amy F

    2017-05-01

    This study sought to examine whether social support moderates the relationship between stress eating and body mass index (BMI) change over the freshman year in males and females. This longitudinal study included 70 college students (72.9% female; M age = 18.23) who completed self-reported measures of stress eating and perceived social support, with objective height and weight measurements collected. Among males, social support moderated the relationship between stress eating and BMI change. Among males, social support may serve as a buffer against the impact of stress eating on weight gain during the freshman year of college.

  15. Features of brain magnetic resonance imaging diffusion-weighted images of aortogenic embolic stroke.

    PubMed

    Shimada, Jun-Ichiro; Yasaka, Masahiro; Wakugawa, Yoshiyuki; Ogata, Toshiyasu; Makihara, Noriko; Ito, Shoichi; Kuwabara, Satoshi; Okada, Yasushi

    2014-01-01

     The features of acute aortogenic embolic stroke on magnetic resonance diffusion-weighted imaging (DWI) have not been fully elucidated, so we compared patients with acute aortogenic embolic stroke and those with acute cardioembolic stroke.  This study included 40 consecutive patients with acute aortogenic embolic stroke, and 40 age- and sex-matched patients with acute cardioembolic stroke. The diagnosis of aortogenic embolic stroke was made when patients met 5 criteria: (1)acute neurologic event lasting >24h; (2) positive signals on DWI; (3) atherosclerotic lesions ≥3.5-mm thick at the aortic arch on transesophageal echocardiography; (4) neuroradiologic features suggesting embolic stroke, such as lesions involving the brain cortex or the re-opening phenomenon of previously occluded vessels on Magnetic Resonance Angiography (MRA); and (5) absence of other embolic sources, including heart disease and carotid stenosis. The number, site, and maximal diameter of the infarct lesions on DWI were compared between the aortogenic and cardiogenic groups. The aortogenic patients more frequently had ≥3 lesions (25.0% vs. 2.5%, P<0.01), lesions with a maximal diameter <30mm (77.5% vs. 20.0%, P< 0.001), and vertebrobasilar system lesions (55.0% vs. 10.0%, P< 0.001) than the cardiogenic patients.  Acute aortogenic embolic stroke is characterized by multiple (≥3) and small lesions, and involvement of the vertebrobasilar system. 

  16. An adaptive diffusion-weighted whole-body magnetic resonance imaging scheme using the multistation approach

    NASA Astrophysics Data System (ADS)

    Han, Yeji

    2016-02-01

    Whole-body diffusion-weighted imaging (DWI) is a useful tool in oncology, which enables fast screening of disseminated tumors, lymph nodes or abscesses in the body. Multistation magnetic resonance imaging (MRI) or continuously moving table (CMT) MRI can be performed to overcome the limited field of view (FOV) of the magnet bore in whole-body DWI. Although CMT-MRI is regarded as a more advanced form of whole-body MRI, it cannot be widely used because most of the available MR systems are not equipped with the required hardware/software to perform CMT. Thus, optimizing the multistation approach for whole-body DWI, which is more widely available and easier to perform with the existing MR systems, is worthwhile. To improve the quality of DW images acquired with the multistation approach, we used different combinations of the built-in body RF coil and the phased-array surface RF coils for reception of the signals in whole-body DWI in this work. If different coils are selectively used in the extended FOV and appropriate reconstruction algorithms are exploited, the screening ability of whole-body DWI can be improved while minimizing the patient's discomfort and the artifacts due to physiological motions.

  17. Recurrence and metastasis of lung cancer demonstrate decreased diffusion on diffusion-weighted magnetic resonance imaging.

    PubMed

    Usuda, Katsuo; Sagawa, Motoyasu; Motomo, Nozomu; Ueno, Masakatsu; Tanaka, Makoto; Machida, Yuichiro; Maeda, Sumiko; Matoba, Munetaka; Tonami, Hisao; Ueda, Yoshimichi; Sakuma, Tsutomu

    2014-01-01

    Diffusion-weighted magnetic resonance imaging (DWI) is reported to be useful for detecting malignant lesions. The purpose of this study is to clarify characteristics of imaging, detection rate and sensitivity of DWI for recurrence or metastasis of lung cancer. A total of 36 lung cancer patients with recurrence or metastasis were enrolled in this study. While 16 patients underwent magnetic resonance imaging (MRI), computed tomography (CT) and positron emission tomography-computed tomography (PET-CT), 17 underwent MRI and CT, and 3 underwent MRI and PET-CT. Each recurrence or metastasis showed decreased diffusion, which was easily recognized in DWI. The detection rate for recurrence or metastasis was 100% (36/36) in DWI, 89% (17/19) in PET-CT and 82% (27/33) in CT. Detection rate of DWI was significantly higher than that of CT (p=0.0244) but not significantly higher than that of PET-CT (p=0.22). When the optimal cutoff value of the apparent diffusion coefficient value was set as 1.70?10-3 mm2/sec, the sensitivity of DWI for diagnosing recurrence or metastasis of lung cancer was 95.6%. DWI is useful for detection of recurrence and metastasis of lung cancer.

  18. Positional pelvic organ prolapse (POP) evaluation using open, weight-bearing magnetic resonance imaging (MRI).

    PubMed

    Friedman, Boris; Stothers, Lynn; Lazare, Darren; Macnab, Andrew

    2015-01-01

    Magnetic resonance imaging (MRI) of patients with pelvic organ prolapse (POP) is completed in the supine position. Open magnetic resonance imaging (MRO) uses vertical magnets, allowing imaging in a variety of upright postures. This pilot study used MRO to evaluate the change of prolapse in different positions compared to non-prolapsed images. In total, 11 women (6 POP, 5 controls) aged 24 to 65 years had 12 MRO images (midline sagittal pelvic line) consecutively when supine, sitting and standing with a full and empty bladder. Lengths between the lowest point of the bladder to the pubococcygeal (PC) and pubopromontoreal (PP) lines in each image were compared, and the ratio of bladder area under the PC and PP lines to the total bladder area. Significant elongation between the PC line and lowest point of the bladder was evident in subjects with POP comparing supine and standing images (p = 0.03), but not controls (p = 0.07). Similarly, this axis was significantly longer in cystocele subjects versus controls only in the standing position. Bladder area under the PC line was significantly increased between supine and standing positions only among subjects with cystocele (p < 0.01), and significantly larger among the study group in the standing position (p < 0.005), less significant in the supine position (p = 0.015), and not significant in the sitting position (p = 0.3). MRO imaging allows us to investigate the effects of upright position and weight bearing on the staging of POP. Imaging patients when sitting and standing identified that significant changes occur in the maximal descent of the bladder.

  19. Influence of aggressive nutritional support on growth and development of very low birth weight infants.

    PubMed

    Xu, Y M; Zhu, X P; Xiao, Z; Yu, L; Zhao, X

    2014-01-01

    To investigate the influence of the early postnatal aggressive nutritional support on the very low birth weight infants (VLBWI) during hospitalization. Surviving premature infants without obvious deformity, with gestational age more than 28 weeks and less than 32 weeks, birth weight 1,000 g to 1,500 g, admitted in NICU in Affiliated Children's Hospital of Suzhou University during 12 hours after birth and stay for two weeks or more from January 2008 to December 2011 were selected, including 44 cases (admitted from September 2010 to December 2011) in the observation group and 36 cases in the control group (admitted from January 2008 and September 2010). The infants in the observation group were treated by aggressive nutritional management, while traditional nutritional management for infants in the control group. The variations of nutritional intake, weight gain, jaundice index, blood biochemistry, serum electrolytes indexes, and complications were compared between the two groups. Compared to the control group, the average growth rate and the albumin (ALB) and prealbumin (PA) levels two week after birth and before leaving hospital of the infants in the observation group was significantly higher (p < 0.05), and the incidence of the extrauterine growth retardation was significantly decreasing (p < 0.05). However, the days of hyperbilirubinemia, highest value of the serum bilirubin, duration ofjaundice, platelets after intravenous nutrition, liver function, blood lipid levels, blood glucose, blood PH, serum creatinine, urea nitrogen, and electrolytes of the first day and the seventh day after birth and the in- cidence of parenteral nutrition-associated cholestasis (PNAC) and necrotizing enterocolitis (NEC) between the two group had no difference (p > 0.05). The implementation of aggressive nutritional management on the with VLBWI was safe and effective.

  20. Preliminary study of diffusion-weighted imaging and magnetic resonance spectroscopy imaging in Kimura disease.

    PubMed

    Wang, Jie; Tang, Zuohua; Feng, Xiaoyuan; Zeng, Wenjiao; Tang, Weijun; Wu, Lingjie; Jin, Lixin

    2014-11-01

    In this study, we evaluated the value of diffusion-weighted imaging (DWI) and magnetic resonance (MR) spectroscopy imaging (MRSI) combined with computed tomography (CT) and conventional MR imaging (MRI) in the diagnosis of Kimura disease (KD). The clinical data and CT and MRI findings of 5 patients with KD proven by histopathologic examination were retrospectively reviewed. Diffusion-weighted imaging and MRSI were performed at 1.5 T in 3 patients with KD. Apparent diffusion coefficient (ADC) values and the choline/creatine ratio of the lesions were compared with those of the contralateral normal parotid glands. All imaging results were compared with histopathologic findings. The typical features of KD were subcutaneous lesions, continuously infiltrative parotid lesions with or without intraparotid lymphadenopathies, and reactive cervical lymphadenopathies on CT and conventional MRI. On DWI, the ADC values of all subcutaneous and infiltrative parotid lesions were higher compared to those of normal parotid glands, and the ADC values of reactive lymphadenopathies were lower compared to both. The choline/creatine levels of subcutaneous and infiltrative parotid lesions were slightly higher than those of normal parotid glands. In conclusion, DWI and MRSI offer valuable information that may be characteristic of KD, which can highly suggest the diagnosis of KD when combined with morphological imaging.

  1. Broadening molecular weight polyethylene distribution by tailoring the silica surface environment on supported metallocenes

    NASA Astrophysics Data System (ADS)

    Barrera, Eliana Galland; Stedile, Fernanda C.; Brambilla, Rodrigo; dos Santos, João H. Z.

    2017-01-01

    The synthesis of nonporous monodisperse chemically modified spherical silica particles was carried out according to the Stöber method. The resulting hybrid silicas were employed in the preparation of supported Cp2ZrCl2. The resulting metal loading, determined by Rutherford Backscattering Spectrometry (RBS), was between 0.15 and 0.48 wt% Zr/SiO2. The systems were evaluated in ethylene polymerization with MAO as the co-catalyst. The presence of ligands can increase catalyst activity and the nature of the employed organosilane ligand on the hybrid silicas were shown to affect the molecular weight distribution leading to polyethylenes with broad polydispersity (Mw/Mn = 3.8) and even with bimodality (Mw/Mn = 12.6).

  2. Silica supported Fe(3)O(4) magnetic nanoparticles for magnetic solid-phase extraction and magnetic in-tube solid-phase microextraction: application to organophosphorous compounds.

    PubMed

    Moliner-Martinez, Y; Vitta, Yosmery; Prima-Garcia, Helena; González-Fuenzalida, R A; Ribera, Antonio; Campíns-Falcó, P; Coronado, Eugenio

    2014-03-01

    This work demonstrates the application of silica supported Fe3O4 nanoparticles as sorbent phase for magnetic solid-phase extraction (MSPE) and magnetic on-line in-tube solid-phase microextraction (Magnetic-IT-SPME) combined with capillary liquid chromatography-diode array detection (CapLC-DAD) to determine organophosphorous compounds (OPs) at trace level. In MSPE, magnetism is used as separation tool while in Magnetic-IT-SPME, the application of an external magnetic field gave rise to a significant improvement of the adsorption of OPs on the sorbent phase. Extraction efficiency, analysis time, reproducibility and sensitivity have been compared. This work showed that Magnetic-IT-SPME can be extended to OPs with successful results in terms of simplicity, speed, extraction efficiency and limit of detection. Finally, wastewater samples were analysed to determine OPs at nanograms per litre.

  3. Assessment of Activity of Crohn Disease by Diffusion-Weighted Magnetic Resonance Imaging

    PubMed Central

    Li, Xue-hua; Sun, Can-hui; Mao, Ren; Zhang, Zhong-wei; Jiang, Xiao-song; Pui, Margaret H.; Chen, Min-hu; Li, Zi-ping

    2015-01-01

    Abstract To assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohn's disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm.2 Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated. The conventional MRE findings and DWI signal intensities were qualitatively scored from 0 to 3. The correlation between Crohn disease activity index (CDAI) and both ADCs and magnetic resonance imaging scores was analyzed. Receiver-operating characteristic curve analysis was used to determine the diagnostic accuracy of CD activity. Of the 47 patients, 25 were active CD (CDAI≥150) and 22 were inactive (CDAI<150). Diffusion-weighted MR imaging and MRE + DWI scores of active CD were significantly higher than that of inactive CD (both P < 0.001). Apparent diffusion coefficients in inflamed segments of active CD were lower than that of inactive CD (P < 0.001). The DWI scores (r = 0.74, P < 0.001), ADCs (r = −0.71, P < 0.001), MRE scores (r = 0.54, P < 0.001), and MRE + DWI scores (r = 0.66, P < 0.001) were all correlated with CDAI. The areas under the receiver-operating characteristics curves for ADCs, DWI scores, MRE scores, and MRE + DWI scores ranged from 0.83 to 0.98. The threshold ADC value of 1.17 × 10−3 mm2/s allowed differentiation of active from inactive CD with 100% sensitivity and 88% specificity. Diffusion-weighted MR imaging and ADC correlated with CD activity, and had excellent diagnostic accuracy for differentiating active from inactive CD. PMID:26512584

  4. Assessment of Activity of Crohn Disease by Diffusion-Weighted Magnetic Resonance Imaging.

    PubMed

    Li, Xue-Hua; Sun, Can-Hui; Mao, Ren; Zhang, Zhong-Wei; Jiang, Xiao-Song; Pui, Margaret H; Chen, Min-Hu; Li, Zi-Ping

    2015-10-01

    To assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohn's disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm. Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated. The conventional MRE findings and DWI signal intensities were qualitatively scored from 0 to 3. The correlation between Crohn disease activity index (CDAI) and both ADCs and magnetic resonance imaging scores was analyzed. Receiver-operating characteristic curve analysis was used to determine the diagnostic accuracy of CD activity. Of the 47 patients, 25 were active CD (CDAI≥150) and 22 were inactive (CDAI<150). Diffusion-weighted MR imaging and MRE + DWI scores of active CD were significantly higher than that of inactive CD (both P < 0.001). Apparent diffusion coefficients in inflamed segments of active CD were lower than that of inactive CD (P < 0.001). The DWI scores (r = 0.74, P < 0.001), ADCs (r = -0.71, P < 0.001), MRE scores (r = 0.54, P < 0.001), and MRE + DWI scores (r = 0.66, P < 0.001) were all correlated with CDAI. The areas under the receiver-operating characteristics curves for ADCs, DWI scores, MRE scores, and MRE + DWI scores ranged from 0.83 to 0.98. The threshold ADC value of 1.17 × 10 mm/s allowed differentiation of active from inactive CD with 100% sensitivity and 88% specificity. Diffusion-weighted MR imaging and ADC correlated with CD activity, and had excellent diagnostic accuracy for differentiating active from inactive CD.

  5. T2-weighted fast spin-echo magnetic resonance imaging of extraocular muscles

    PubMed Central

    Demer, Joseph L.; Dushyanth, Anita

    2011-01-01

    Purpose Magnetic resonance imaging (MRI) can provide unique information about extraocular muscle (EOM) structure and function. Prior high-resolution motility imaging studies employed T1 weighting, which provides intrinsic contrast of dark-appearing EOMs against bright orbital fat and is suitable for intravenous contrast. However, time-consuming T1 sequences are subject to motion artifacts. We evaluated an alternative T2-weighted fast spin-echo pulse sequence that emphasizes tissue-free fluid. Methods We prospectively used high resolution, surface coil technique for orbital MRI at 1.5T in 21 normal and 113 living strabismic subjects and 2 monkey cadavers using T2 fast spin-echo (T2FSE) weighting (long repetition time, short echo time). T2FSE was compared with T1 in 17 subjects, and with T1 in 506 different living subjects, and 12 cadavers. Results For 2 mm thick coronal MRIs of 312 μm resolution spanning the entire orbit, T1 acquisition required 218 seconds, whereas T2FSE required 150 seconds (31% faster). T2-defined the globe border better, and provided intrinsic contrast between EOMs and their pulleys. While both T1 and T2 demonstrated motor nerves to EOMs in living subjects, only T1 was satisfactory with injected contrast and in cadavers. Conclusions For motility imaging, T2FSE is faster than T1 MRI and demonstrates superior tissue details of EOMs and other orbital tissues. T2FSE of the orbits can be performed using widely available standard equipment. We suggest that T2FSE be the preferred method for clinical imaging of EOM structure, function, and innervation, although T1 may be more appropriate when intravenous contrast must be employed. PMID:21397801

  6. Is an Apple Magnetic: Magnetic Response of Everyday Materials Supporting Views about the Nature of Science

    ERIC Educational Resources Information Center

    Laumann, Daniel

    2017-01-01

    Magnetism and its various applications are essential for our daily life and for many technological developments. The term "magnetism" is almost always used as a synonym for ferromagnetism. However, the magnetic properties of the elements of the periodic table indicate that the vast majority of elements are not ferromagnetic, but rather,…

  7. Patient self-efficacy and spouse perception of spousal support are associated with lower patient weight: baseline results from a spousal support behavioral intervention.

    PubMed

    Gallagher, Patrick; Yancy, William S; Jeffreys, Amy S; Coffman, Cynthia J; Weinberger, Morris; Bosworth, Hayden B; Voils, Corrine I

    2013-01-01

    Obesity and related chronic illnesses are leading causes of death and excessive health care costs, necessitating identification of factors that can help patients achieve and maintain healthy weight. Greater self-efficacy and perceived spousal support in patients have been associated with successful weight management. The current study also assesses self-efficacy and perceived support in spouses and whether these factors are related to patient weight. At baseline of a spousal support trial, patients and spouses (N = 255 couples) each completed measures of self-efficacy and spousal support for their own exercise and healthy eating behaviors. We fit a multivariable regression model to examine the relationship between these factors and patient weight. Patients were 95% males and 65% Whites, with average age of 61 years (SD = 12) and weight of 212 lbs (SD = 42). Spouses were 64% Whites, with average age of 59 years (SD = 12). Factors associated with lower patient weight were older patient age (estimate = -0.8 lbs, p < .01), normal blood pressure (estimate = -17.6 lbs, p < .01), higher patient self-efficacy for eating healthy (estimate = -3.8 lbs, p = .02), and spouse greater perceived support for eating healthy (estimate = -10.0 lbs, p = .03). Future research should explore the causal pathways between perceived support and health outcomes to establish whether patient support behaviors could be a point of intervention for weight management.

  8. Cryomdoule Test Stand Reduced-Magnetic Support Design at Fermilab

    SciTech Connect

    McGee, Mike; Chandrasekaran, Saravan Kumar; Crawford, Anthony; Harms, Elvin; Leibfritz, Jerry; Wu, Genfa

    2016-06-01

    In a partnership with SLAC National Accelerator Laboratory (SLAC) and Jefferson Lab, Fermilab will assemble and test 17 of the 35 total 1.3 GHz cryomodules for the Linac Coherent Light Source II (LCLS-II) Project. These devices will be tested at Fermilab's Cryomodule Test Facility (CMTF) within the Cryomodule Test Stand (CMTS-1) cave. The problem of magnetic pollution became one of major issues during design stage of the LCLS-II cryomodule as the average quality factor of the accelerating cavities is specified to be 2.7 x 10¹⁰. One of the possible ways to mitigate the effect of stray magnetic fields and to keep it below the goal of 5 mGauss involves the application of low permeable materials. Initial permeability and magnetic measurement studies regarding the use of 316L stainless steel material indicated that cold work (machining) and heat affected zones from welding would be acceptable.

  9. The global structure of magnetic fields which support quiescent prominences

    NASA Technical Reports Server (NTRS)

    Anzer, U.

    1985-01-01

    Magnetic fields in quiescent prominences were observed, but only recently has it become possible to measure the full magnetic field vector. The component of the field along the line of sight, B (parallel) can be uniquely determined, whereas for the component perpendicular to the line of sight B (perpendicular) and -B (perpendicular) are indistinguishable. An ambiguity remains in the actual magnetic field vector, in particular with respect to its orientation relative to the prominence axis. A sample of more than 100 prominences were studied. A more detailed analysis of 10 prominences are presented, and then set these prominence fields into relation to the underlying photospheric fields. It is found from statistical analysis of several hundred prominences that in 25% of the cases the field penetrates the prominence directly, whereas in 75% the field orientation in the prominence is reversed.

  10. Two Models of Magnetic Support for Photoevaporated Molecular Clouds

    SciTech Connect

    Ryutov, D; Kane, J; Mizuta, A; Pound, M; Remington, B

    2004-05-05

    The thermal pressure inside molecular clouds is insufficient for maintaining the pressure balance at an ablation front at the cloud surface illuminated by nearby UV stars. Most probably, the required stiffness is provided by the magnetic pressure. After surveying existing models of this type, we concentrate on two of them: the model of a quasi-homogeneous magnetic field and the recently proposed model of a ''magnetostatic turbulence''. We discuss observational consequences of the two models, in particular, the structure and the strength of the magnetic field inside the cloud and in the ionized outflow. We comment on the possible role of reconnection events and their observational signatures. We mention laboratory experiments where the most significant features of the models can be tested.

  11. [The clinical application of diffusion weighted magnetic resonance imaging to acute cerebrovascular disorders].

    PubMed

    Chu, B C; Miyasaka, K

    1998-09-01

    Diffusion is a measure of motion freedom and is a sensitive parameter to characterize the tissue at the microscopic level. The methods of measuring in vivo diffusion by magnetic resonance imaging (MRI) have been based mainly on the addition of two motion-probing gradients (MPG) to the spin echo sequence to produce signal attenuation for the spins moving at random. The resultant MR images reflect the intravoxel incoherent motions (IVIM), which contain both water molecule diffusion and perfusion in the capillary network, and can be quantified by an apparent diffusion coefficient (ADC). Diffusion weighted MRI, acquired from IVIM MR imaging by the addition of the very strong MPG predicate water diffusion and anisotropy. High signal or reduced ADC can be observed in case of the slower diffusion. The anisotropy depends upon the orientation of the subjects and the gradients. Greater signal attenuation (faster diffusion) can be observed when the relative orientation of white matter tracts to the MPG is parallel as compared to that obtained with a perpendicular alignment. This anisotropy may preclude the detection or delineation of an ischemic lesion. Diffusion tensor trace has been designated to eliminate this anisotropy effect. In ischemic animal models, low signal (fast diffusion) and high signal (slow diffusion) have been noted in the vasogenic edema and cytotoxic edema, respectively. High signal appears only in case of cerebral blood flow below 15-20 ml/100 g per minute, a value identical to the threshold of tissue at high energetic metabolism and ion homeostasis. ADC value decreases following the cerebral vessel occlusion, or remains unchanged when collateral circulation develops. It has been speculated that reduction in ADC reflects the water shift from extracellular space to intracellular space due to the membrane permeability and/or intracellular osmolality increase. These results suggest that diffusion weighted MRI correlates well with the cell metabolism, and

  12. Synchronous Control Effort Minimized for Magnetic-Bearing-Supported Shaft

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2001-01-01

    Various disturbances that are synchronous with the shaft speed can complicate radial magnetic bearing control. These include position sensor target irregularities (runout) and shaft imbalance. The method presented here allows the controller to ignore all synchronous harmonics of the shaft position input (within the closed-loop bandwidth) and to respond only to asynchronous motions. The result is reduced control effort.

  13. Contextual weighting for Support Vector Machines in literature mining: an application to gene versus protein name disambiguation.

    PubMed

    Pahikkala, Tapio; Ginter, Filip; Boberg, Jorma; Järvinen, Jouni; Salakoski, Tapio

    2005-06-22

    The ability to distinguish between genes and proteins is essential for understanding biological text. Support Vector Machines (SVMs) have been proven to be very efficient in general data mining tasks. We explore their capability for the gene versus protein name disambiguation task. We incorporated into the conventional SVM a weighting scheme based on distances of context words from the word to be disambiguated. This weighting scheme increased the performance of SVMs by five percentage points giving performance better than 85% as measured by the area under ROC curve and outperformed the Weighted Additive Classifier, which also incorporates the weighting, and the Naive Bayes classifier. We show that the performance of SVMs can be improved by the proposed weighting scheme. Furthermore, our results suggest that in this study the increase of the classification performance due to the weighting is greater than that obtained by selecting the underlying classifier or the kernel part of the SVM.

  14. Contextual weighting for Support Vector Machines in literature mining: an application to gene versus protein name disambiguation

    PubMed Central

    Pahikkala, Tapio; Ginter, Filip; Boberg, Jorma; Järvinen, Jouni; Salakoski, Tapio

    2005-01-01

    Background The ability to distinguish between genes and proteins is essential for understanding biological text. Support Vector Machines (SVMs) have been proven to be very efficient in general data mining tasks. We explore their capability for the gene versus protein name disambiguation task. Results We incorporated into the conventional SVM a weighting scheme based on distances of context words from the word to be disambiguated. This weighting scheme increased the performance of SVMs by five percentage points giving performance better than 85% as measured by the area under ROC curve and outperformed the Weighted Additive Classifier, which also incorporates the weighting, and the Naive Bayes classifier. Conclusion We show that the performance of SVMs can be improved by the proposed weighting scheme. Furthermore, our results suggest that in this study the increase of the classification performance due to the weighting is greater than that obtained by selecting the underlying classifier or the kernel part of the SVM. PMID:15972097

  15. Is an Apple Magnetic: Magnetic Response of Everyday Materials Supporting Views About the Nature of Science

    NASA Astrophysics Data System (ADS)

    Laumann, Daniel

    2017-03-01

    Magnetism and its various applications are essential for our daily life and for many technological developments. The term magnetism is almost always used as a synonym for ferromagnetism. However, the magnetic properties of the elements of the periodic table indicate that the vast majority of elements are not ferromagnetic, but rather, diamagnetic or paramagnetic. Typically, only ferromagnetism is discussed in classrooms, which can create a distorted picture. This article supplies the further development of an experiment demonstrating the dia- and paramagnetic properties with an electronic balance and a neodymium magnet. It focuses on an investigation of ordinary materials that occur in pupils' everyday environment. The experiment is applicable both for a quantitative measurement of the magnetic (volume) susceptibility χV and can serve as a phenomenological approach to dia- and paramagnetism. Moreover, it encourages a discussion about typical beliefs regarding the nature of science, comparing the behavior of common objects in weak and in strong magnetic fields.

  16. Magnetic Silica Supported Copper: A Modular Approach to Aqueous Ullmann-type Amination of Aryl Halides

    EPA Science Inventory

    One-pot synthesis of magnetic silica supported copper catalyst has been described via in situ generated magnetic silica (Fe3O4@SiO2); the catalyst can be used for the efficacious amination of aryl halides in aqueous medium under microwave irradiation.

  17. Magnetic Silica Supported Copper: A Modular Approach to Aqueous Ullmann-type Amination of Aryl Halides

    EPA Science Inventory

    One-pot synthesis of magnetic silica supported copper catalyst has been described via in situ generated magnetic silica (Fe3O4@SiO2); the catalyst can be used for the efficacious amination of aryl halides in aqueous medium under microwave irradiation.

  18. Effect of partial weight-supported treadmill gait training on balance in patients with Parkinson disease.

    PubMed

    Ganesan, Mohan; Sathyaprabha, Talakad N; Gupta, Anupam; Pal, Pramod Kumar

    2014-01-01

    To investigate the role of conventional gait training and partial weight-supported treadmill gait training (PWSTT) in improving the balance of patients with Parkinson disease (PD). Prospective randomized controlled design. National-level university tertiary hospital for mental health and neurosciences. Sixty patients with PD fulfilling the United Kingdom Brain Bank PD diagnostic criteria were recruited from the neurology outpatient department and movement disorder clinic. The patients were randomly assigned into 3 equal groups: (1) a control group that only received a stable dosage of dopaminomimetic drugs; (2) a conventional gait training (CGT) group that received a stable dosage of dopaminomimetic drugs and conventional gait training; and (3) a PWSTT group that received a stable dosage of dopaminomimetic drugs and PWSTT with unloading of 20% of body weight. The sessions for the CGT and PWSTT groups were provided for 30 minutes per day, 4 days per week, for 4 weeks (16 sessions). The Unified Parkinson Disease Rating Scale (UPDRS) motor score, dynamic posturography, Berg Balance Scale, and Tinetti performance-oriented mobility assessment (POMA) were used as main outcome measures. A significant interaction effect was observed in the UPDRS motor score, mediolateral index, Berg Balance Scale, limits of stability (LOS) total score, POMA gait score, and balance score. Post-hoc analysis showed that in comparison with the control group, the PWSTT group had a significantly better UPDRS motor score, balance indices, LOS in 8 directions, POMA gait, and balance score. The CGT group had a significantly better POMA gait score compared with control subjects. Compared with the CGT group, the PWSTT group had a significantly better UPDRS motor score, mediolateral index, POMA gait score, and LOS total score. PWSTT may be a better interventional choice than CGT for gait and balance rehabilitation in patients with PD. Copyright © 2014 American Academy of Physical Medicine and

  19. Magnetic Carbon Supported Palladium Nanoparticles: An Efficient and Sustainable Catalyst for Hydrogenation Reactions

    EPA Science Inventory

    Magnetic carbon supported Pd catalyst has been synthesized via in situ generation of nanoferrites and incorporation of carbon from renewable cellulose via calcination; the catalyst can be used for the hydrogenation of alkenes and reduction of aryl nitro compounds.

  20. Magnetic Carbon Supported Palladium Nanoparticles: An Efficient and Sustainable Catalyst for Hydrogenation Reactions

    EPA Science Inventory

    Magnetic carbon supported Pd catalyst has been synthesized via in situ generation of nanoferrites and incorporation of carbon from renewable cellulose via calcination; the catalyst can be used for the hydrogenation of alkenes and reduction of aryl nitro compounds.

  1. Diagnostic accuracy of susceptibility-weighted magnetic resonance imaging for the evaluation of pineal gland calcification

    PubMed Central

    Böker, Sarah M.; Bender, Yvonne Y.; Diederichs, Gerd; Fallenberg, Eva M.; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R.

    2017-01-01

    Objectives To determine the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the detection of pineal gland calcifications (PGC) compared to conventional magnetic resonance imaging (MRI) sequences, using computed tomography (CT) as a reference standard. Methods 384 patients who received a 1.5 Tesla MRI scan including SWMR sequences and a CT scan of the brain between January 2014 and October 2016 were retrospectively evaluated. 346 patients were included in the analysis, of which 214 showed PGC on CT scans. To assess correlation between imaging modalities, the maximum calcification diameter was used. Sensitivity and specificity and intra- and interobserver reliability were calculated for SWMR and conventional MRI sequences. Results SWMR reached a sensitivity of 95% (95% CI: 91%-97%) and a specificity of 96% (95% CI: 91%-99%) for the detection of PGC, whereas conventional MRI achieved a sensitivity of 43% (95% CI: 36%-50%) and a specificity of 96% (95% CI: 91%-99%). Detection rates for calcifications in SWMR and conventional MRI differed significantly (95% versus 43%, p<0.001). Diameter measurements between SWMR and CT showed a close correlation (R2 = 0.85, p<0.001) with a slight but not significant overestimation of size (SWMR: 6.5 mm ± 2.5; CT: 5.9 mm ± 2.4, p = 0.02). Interobserver-agreement for diameter measurements was excellent on SWMR (ICC = 0.984, p < 0.0001). Conclusions Combining SWMR magnitude and phase information enables the accurate detection of PGC and offers a better diagnostic performance than conventional MRI with CT as a reference standard. PMID:28278291

  2. Diagnostic accuracy of susceptibility-weighted magnetic resonance imaging for the evaluation of pineal gland calcification.

    PubMed

    Adams, Lisa C; Böker, Sarah M; Bender, Yvonne Y; Diederichs, Gerd; Fallenberg, Eva M; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R

    2017-01-01

    To determine the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the detection of pineal gland calcifications (PGC) compared to conventional magnetic resonance imaging (MRI) sequences, using computed tomography (CT) as a reference standard. 384 patients who received a 1.5 Tesla MRI scan including SWMR sequences and a CT scan of the brain between January 2014 and October 2016 were retrospectively evaluated. 346 patients were included in the analysis, of which 214 showed PGC on CT scans. To assess correlation between imaging modalities, the maximum calcification diameter was used. Sensitivity and specificity and intra- and interobserver reliability were calculated for SWMR and conventional MRI sequences. SWMR reached a sensitivity of 95% (95% CI: 91%-97%) and a specificity of 96% (95% CI: 91%-99%) for the detection of PGC, whereas conventional MRI achieved a sensitivity of 43% (95% CI: 36%-50%) and a specificity of 96% (95% CI: 91%-99%). Detection rates for calcifications in SWMR and conventional MRI differed significantly (95% versus 43%, p<0.001). Diameter measurements between SWMR and CT showed a close correlation (R2 = 0.85, p<0.001) with a slight but not significant overestimation of size (SWMR: 6.5 mm ± 2.5; CT: 5.9 mm ± 2.4, p = 0.02). Interobserver-agreement for diameter measurements was excellent on SWMR (ICC = 0.984, p < 0.0001). Combining SWMR magnitude and phase information enables the accurate detection of PGC and offers a better diagnostic performance than conventional MRI with CT as a reference standard.

  3. Relationship between diffusion-weighted magnetic resonance imaging and histological tumor grading of hepatocellular carcinoma.

    PubMed

    Nakanishi, Mitsuru; Chuma, Makoto; Hige, Shuhei; Omatsu, Tokuhiko; Yokoo, Hideki; Nakanishi, Kazuaki; Kamiyama, Toshiya; Kubota, Kanako; Haga, Hironori; Matsuno, Yoshihiro; Onodera, Yuya; Kato, Mototsugu; Asaka, Masahiro

    2012-04-01

    Intrahepatic and extrahepatic recurrence remains a significant problem for hepatocellular carcinoma (HCC). The aim of this study was to determine the usefulness of diffusion-weighted magnetic resonance imaging (DWI) for histological tumor grading and preoperative prediction of early HCC recurrence within 6 months of operation. A total of 44 patients who had undergone hepatic resection for HCC (50 nodules) were reviewed retrospectively. DWI was performed within 30 days before hepatectomy, and apparent diffusion coefficients (ADCs) were measured using 2 methods: mean ADC and minimum-spot ADC. Relationships between ADCs and histological differentiation and between ADCs and early recurrence of HCC were analyzed. Mean ADC was significantly lower in poorly differentiated HCC (n=18, 1.07±0.15×10(-3) mm2/s) than in moderately differentiated HCC (n=29, 1.29±0.21×10(-3) mm2/s; P<.05). Minimum-spot ADC was significantly lower in poorly differentiated HCC (n=18, 0.69±0.19×10(-3) mm2/s) than in well-differentiated HCC (n=3, 1.15±0.10×10(-3) mm2; P<.01) or in moderately differentiated HCC (n=29, 0.98±0.18×10(-3) mm2/s; P<.0001). Of 34 patients who were able to be observed for >6 months after resection, 9 showed early recurrence. Minimum-spot ADC was significantly lower in patients with early recurrence (n=9, 0.64±0.24×10(-3) mm2/s) than in patients without early recurrence (n=25, 0.88±0.19×10(-3) mm2/s; P<.05). On multivariate analysis, minimum-spot ADC was a significant risk factor for early recurrence (P<.05). Quantitative measurement of ADC of HCC with magnetic resonance diffusion weighted imaging is a promising functional imaging tool in the prediction of histological grade and early recurrence before treatment.

  4. Magnetic resonance imaging of prostate cancer: diffusion-weighted imaging in comparison with sextant biopsy.

    PubMed

    Yamamura, Jin; Salomon, Georg; Buchert, Ralph; Hohenstein, Arne; Graessner, Joachim; Huland, Hartwig; Graefen, Markus; Adam, Gerhard; Wedegaertner, Ulrike

    2011-01-01

    To retrospectively evaluate the impact of diffusion-weighted imaging (DWI) on the detection of prostate cancer in comparison with sextant biopsy. Fifty patients with clinical suspicion of prostate cancer underwent a combined endorectal-body-phased array magnetic resonance imaging examination at a 1.5 T magnetic resonance imaging (Siemens, Erlangen, Germany). The DWI was performed using b values of 50, 400, 800 s/mm. The prostate was divided into sextants, including the apex, the middle aspect, and the base for the left and right sides, separately. Regions of interest were placed in the peripheral zone of each sextant to evaluate the apparent diffusion coefficient (ADC) values. The results of the DWI were compared side by side with the findings of the histological examination of endorectal sonographically guided sextant biopsy. The sensitivity and specificity of ADC for the identification of the tumor tissue were computed for variable discrimination thresholds to evaluate its receiver operating characteristic. An association between ADC and Gleason score was tested for both the whole study group and on an individual basis using the nonparametric Spearman ρ test and the Pearson correlation, respectively. Histopathology identified tumor tissue in 21 (42%) of the 50 patients. The ADC value was 1.65 ± 0.32 mm/s 10 in normal tissue and 0.96 ± 0.24 mm/s 10 in tumor tissue (mean ± 1 SD). The area under the receiver operating characteristic curve was 0.966. Using the discrimination threshold 1.21 mm/s 10, for example, the ADC value provided a sensitivity of 0.92 and a specificity of 0.93. There was a highly significant negative correlation between the ADC value and the Gleason score in the tumor-positive tissue probes (n = 62, ρ = -0.405, P = 0.001) in the whole study group. On the individual patient basis, the Pearson correlation revealed a mean coefficient of r = -0.89 (SD ± 0.12) with a P < 0.001. Diffusion-weighted imaging of the prostate can be used to

  5. Prediction of hemorrhagic transformation following acute stroke: role of diffusion- and perfusion-weighted magnetic resonance imaging.

    PubMed

    Tong, D C; Adami, A; Moseley, M E; Marks, M P

    2001-04-01

    Acute diffusion-weighted (DWI) and perfusion-weighted (PWI) magnetic resonance imaging (MRI) findings may correlate with secondary hemorrhagic transformation (HT) risk in patients with stroke. This information could be of value, particularly in individuals being considered for thrombolytic therapy. To determine the relationship between DWI and PWI findings and the risk of secondary HT in patients with acute stroke. Retrospective case series. Academic medical center. Twenty-seven patients with acute stroke capable of being evaluated with DWI/PWI 8 hours or less after symptom onset. Apparent diffusion coefficient values, perfusion delay measurements, and subsequent MRI or computed tomographic scans detected HT. The mean +/- SD apparent diffusion coefficient of ischemic regions that experienced HT was significantly lower than the overall mean +/- SD apparent diffusion coefficient of all ischemic areas analyzed (0.510 +/- 0.140 x 10(-3) mm(2)/s vs 623 +/- 0.113 x 10(-3) mm(2)/s; P =.004). This difference remained significant when comparing the HT-destined ischemic areas with the non-HT-destined areas within the same ischemic lesion (P =.02). Patients receiving recombinant tissue-type plasminogen activator (rt-PA) experienced HT significantly earlier than patients not receiving rt-PA (P =.002). Moreover, a persistent perfusion deficit in the area of subsequent hemorrhage at 3 to 6 hours after the initial MRI scan was identified in significantly more patients who experienced HT than in those who did not (83% vs 30%; P =.03). Both DWI and PWI scans detect abnormalities that are associated with HT. These findings support a role for MRI in identifying patients who are at increased risk for secondary HT following acute ischemic stroke.

  6. Evaluation of Angiographic and Technical Aspects of Carotid Stenting with Diffusion-Weighted Magnetic Resonance Imaging

    SciTech Connect

    Blasel, Stella Hattingen, Elke; Berkefeld, Joachim; Kurre, Wiebke; Morawe, Gerald; Zanella, Friedhelm; Rochemont, Richard Du Mesnil de

    2009-07-15

    The detection of clinically silent ischemic lesions on postprocedural diffusion-weighted magnetic resonance images has become a preferred method for the description of embolic risks. The purpose of this single-center study was to evaluate whether diffusion-weighted imaging (DWI) could determine material related or technical risk factors of filter-protected carotid stenting. Eighty-four patients with symptomatic severe ({>=}60%) carotid artery stenoses received filter-protected carotid stenting. Standard DWI (b = 1000) was performed within 48 h before and after carotid stenting. The occurrence and load of new postinterventional DWI lesions were assessed. Multivariate analysis was performed to determine risk factors associated with DWI lesions, with emphasis on technical factors such as use of different access devices (guiding catheter method vs. long carotid sheath method), type of stent (open-cell nitinol stent vs. closed-cell Wallstent), and protective device (filters with 80-{mu}m vs. 110-120-{mu}m pore size). Markers for generalized atherosclerosis and for degree and site of stenosis were assessed to allow comparison of adequate risk profiles. Access, protective device, and stent type were not significantly associated with new embolic DWI lesions when we compared patients with equivalent risk profiles (long carotid sheath method 48% [11 of 23] vs. guiding catheter method 44% [27 of 61], Wallstent 47% [15 of 32] vs. nitinol stent 44% [23 of 52], and small pore size filter 61% [11 of 18] vs. large pore size filter 41% [27 of 66]). Single-center DWI studies with a moderate number of cases are inadequate for proper assessment of the embolic risk of technical- or material-related risk factors in carotid stenting. Larger multicenter studies with more cases are needed.

  7. Vibration study of the APS magnet support assemblies

    SciTech Connect

    Wambsganss, M.W.; Jendrzejczyk, J.A.; Chen, S.S.

    1990-11-01

    Stability of the positron closed orbit is a requirement for successful operation of the Advanced Photon Source. The fact that vibration of the storage ring quadrupole magnets can lead to distortion of the positron closed orbit and to potentially unacceptable beam emittance growth provides the motivation for the subject studies. Low frequency vibrations can be controlled with steering magnets using feedback systems, provided the vibration amplitudes are within the dynamic range of the controllers. High frequency vibration amplitudes, on the other hand, are out of the range of the controller and, therefore must be limited to ensure the emittance growth will not exceed a prescribed value. Vibration criteria were developed based on the requirement that emittance growth be limited to 10 percent. Recognizing that the quadrupole magnets have the most significant effect, three different scenarios were considered: vibration of a single quadrupole within the storage ring, random vibration of all the quadrupoles in the ring, and the hypothetical case of a plane wave sweeping across the site and the quadrupoles following the motion of the plane wave. The maximum allowable peak vibration amplitudes corresponding to these three vibration scenarios are given. The criteria associated with the passage of a plane wave is dependent on wavelength, or, alternatively, on frequency given the wave speed. The wave speed used is that measured as a part of the geotechnical investigation at the APS site.

  8. Diffusion-weighted magnetic resonance imaging: detection of ischemic injury 39 minutes after onset in a stroke patient.

    PubMed

    Yoneda, Y; Tokui, K; Hanihara, T; Kitagaki, H; Tabuchi, M; Mori, E

    1999-06-01

    A neurologist witnessed the in-hospital onset of an ischemic stroke in a 71-year-old right-handed male who suddenly developed global aphasia and right hemiplegia. Diffusion-weighted magnetic resonance imaging (DWI) 39 minutes after the ictus demonstrated high signals in the left internal carotid artery territory. T1- and T2-weighted images failed to detect this change. Magnetic resonance angiography showed occlusions in branches of the left anterior and middle cerebral arteries and an atheromatous stenotic lesion in the ipsilateral proximal internal carotid artery. The patient was treated with intravenous heparin and low molecular dextran solution. Repeated magnetic resonance imagings identified an infarction slightly smaller than the abnormality demonstrated by the initial DWI. DWI detects hyperacute ischemic injury within 1 hour of symptom onset in human ischemic stroke.

  9. High-Quality T2-Weighted 4-Dimensional Magnetic Resonance Imaging for Radiation Therapy Applications

    SciTech Connect

    Du, Dongsu; Caruthers, Shelton D.; Glide-Hurst, Carri; Low, Daniel A.; Li, H. Harold; Mutic, Sasa; Hu, Yanle

    2015-06-01

    Purpose: The purpose of this study was to improve triggering efficiency of the prospective respiratory amplitude-triggered 4-dimensional magnetic resonance imaging (4DMRI) method and to develop a 4DMRI imaging protocol that could offer T2 weighting for better tumor visualization, good spatial coverage and spatial resolution, and respiratory motion sampling within a reasonable amount of time for radiation therapy applications. Methods and Materials: The respiratory state splitting (RSS) and multi-shot acquisition (MSA) methods were analytically compared and validated in a simulation study by using the respiratory signals from 10 healthy human subjects. The RSS method was more effective in improving triggering efficiency. It was implemented in prospective respiratory amplitude-triggered 4DMRI. 4DMRI image datasets were acquired from 5 healthy human subjects. Liver motion was estimated using the acquired 4DMRI image datasets. Results: The simulation study showed the RSS method was more effective for improving triggering efficiency than the MSA method. The average reductions in 4DMRI acquisition times were 36% and 10% for the RSS and MSA methods, respectively. The human subject study showed that T2-weighted 4DMRI with 10 respiratory states, 60 slices at a spatial resolution of 1.5 × 1.5 × 3.0 mm{sup 3} could be acquired in 9 to 18 minutes, depending on the individual's breath pattern. Based on the acquired 4DMRI image datasets, the ranges of peak-to-peak liver displacements among 5 human subjects were 9.0 to 12.9 mm, 2.5 to 3.9 mm, and 0.5 to 2.3 mm in superior-inferior, anterior-posterior, and left-right directions, respectively. Conclusions: We demonstrated that with the RSS method, it was feasible to acquire high-quality T2-weighted 4DMRI within a reasonable amount of time for radiation therapy applications.

  10. Individual joint contribution to body weight support in the affected lower limb during walking in post-stroke hemiplegia.

    PubMed

    Kim, Woo-Sub; Kim, Min Joo

    2017-04-01

    Patients with post-stroke hemiplegia have difficulty with body weight support during walking. However, it is unclear which intra-limb strategy for body weight support tends to predominate, and how the intra-limb strategy is related to gait function. Support moment and individual joint contribution to support moment are the parameters that reflect intra-limb strategy for body weight supporting. The aim of this study was to test whether support moment and individual joint contributions differed between post-stroke subjects with different gait function. Laboratory gait analysis was performed for 14 non-hemiplegic elderly (NE) and 12 post-stroke hemiplegic elderly walking without cane (HNC) and 11 walking with a cane (HWC). Data were obtained for the vertical ground reaction force (vGRF) curve, 1st peak and 2nd peak of vGRF and corresponding temporal occurrences. Support moment (Ms) was numerical sum of hip extension, knee extension, and ankle plantar flexion moment. Individual joint contribution was calculated as the ratio of each joint moment to support moment. At temporal occurrences of vGRF peaks, Ms and individual joint contribution to Ms were calculated. Ms and individual joint contribution to Ms were compared among NE, HNC and HWC groups. Each subject's characteristics of individual joint contribution to Ms were explored. At the 1st peak of vGRF, support moments were similar among the three groups. However, the hip contributions were significantly greater in the NE group than in the other two groups, the ankle contributions were significantly greater in the HNC group than in the NE group. Notably, some of the subjects with post-stroke hemiplegia showed atypical characteristics that did not correspond to the group characteristics. Observing support moment and individual joint contribution is helpful to ascertain not only group characteristics, but also individual characteristics of intra-limb strategy for weight support in patients with post-stroke hemiplegia.

  11. Magnetic resonance susceptibility weighted imaging in neurosurgery: current applications and future perspectives.

    PubMed

    Di Ieva, Antonio; Lam, Timothy; Alcaide-Leon, Paula; Bharatha, Aditya; Montanera, Walter; Cusimano, Michael D

    2015-12-01

    Susceptibility weighted imaging (SWI) is a relatively new imaging technique. Its high sensitivity to hemorrhagic components and ability to depict microvasculature by means of susceptibility effects within the veins allow for the accurate detection, grading, and monitoring of brain tumors. This imaging modality can also detect changes in blood flow to monitor stroke recovery and reveal specific subtypes of vascular malformations. In addition, small punctate lesions can be demonstrated with SWI, suggesting diffuse axonal injury, and the location of these lesions can help predict neurological outcome in patients. This imaging technique is also beneficial for applications in functional neurosurgery given its ability to clearly depict and differentiate deep midbrain nuclei and close submillimeter veins, both of which are necessary for presurgical planning of deep brain stimulation. By exploiting the magnetic susceptibilities of substances within the body, such as deoxyhemoglobin, calcium, and iron, SWI can clearly visualize the vasculature and hemorrhagic components even without the use of contrast agents. The high sensitivity of SWI relative to other imaging techniques in showing tumor vasculature and microhemorrhages suggests that it is an effective imaging modality that provides additional information not shown using conventional MRI. Despite SWI's clinical advantages, its implementation in MRI protocols is still far from consistent in clinical usage. To develop a deeper appreciation for SWI, the authors here review the clinical applications in 4 major fields of neurosurgery: neurooncology, vascular neurosurgery, neurotraumatology, and functional neurosurgery. Finally, they address the limitations of and future perspectives on SWI in neurosurgery.

  12. Robust optimal design of diffusion-weighted magnetic resonance experiments for skin microcirculation

    NASA Astrophysics Data System (ADS)

    Choi, J.; Raguin, L. G.

    2010-10-01

    Skin microcirculation plays an important role in several diseases including chronic venous insufficiency and diabetes. Magnetic resonance (MR) has the potential to provide quantitative information and a better penetration depth compared with other non-invasive methods such as laser Doppler flowmetry or optical coherence tomography. The continuous progress in hardware resulting in higher sensitivity must be coupled with advances in data acquisition schemes. In this article, we first introduce a physical model for quantifying skin microcirculation using diffusion-weighted MR (DWMR) based on an effective dispersion model for skin leading to a q-space model of the DWMR complex signal, and then design the corresponding robust optimal experiments. The resulting robust optimal DWMR protocols improve the worst-case quality of parameter estimates using nonlinear least squares optimization by exploiting available a priori knowledge of model parameters. Hence, our approach optimizes the gradient strengths and directions used in DWMR experiments to robustly minimize the size of the parameter estimation error with respect to model parameter uncertainty. Numerical evaluations are presented to demonstrate the effectiveness of our approach as compared to conventional DWMR protocols.

  13. Eu, Gd-Codoped Yttria Nanoprobes for Optical and T1-Weighted Magnetic Resonance Imaging

    PubMed Central

    Atabaev, Timur Sh; Lee, Jong Ho; Shin, Yong Cheol; Han, Dong-Wook; Choo, Ki Seok; Jeon, Ung Bae; Hwang, Jae Yeon; Yeom, Jeong A.; Kim, Hyung-Kook; Hwang, Yoon-Hwae

    2017-01-01

    Nanoprobes with multimodal functionality have attracted significant interest recently because of their potential applications in nanomedicine. This paper reports the successful development of lanthanide-doped Y2O3 nanoprobes for potential applications in optical and magnetic resonance (MR) imaging. The morphology, structural, and optical properties of these nanoprobes were characterized by transmission electron microscope (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and photoluminescence (PL). The cytotoxicity test showed that the prepared lanthanide-doped Y2O3 nanoprobes have good biocompatibility. The obvious contrast enhancement in the T1-weighted MR images suggested that these nanoprobes can be used as a positive contrast agent in MRI. In addition, the clear fluorescence images of the L-929 cells incubated with the nanoprobes highlight their potential for optical imaging. Overall, these results suggest that prepared lanthanide-doped Y2O3 nanoprobes can be used for simultaneous optical and MR imaging. PMID:28336868

  14. Diffusion-Weighted Magnetic Resonance Imaging in Evaluation of Gastric Cancer

    PubMed Central

    Kantarci, Mecit; Yuce, Ihsan; Yalcin, Ahmet; Yildirgan, M. Ilhan; Cayir, Kerim; Eren, Suat; Atamanalp, S. Selcuk

    2010-01-01

    Objective: To investigate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in the diagnosis of gastric tumors and discuss the diagnostic importance and potential use of apparent diffusion coefficient (ADC) measurements. Materials and Methods: Beginning in March 2009, DW-MRI was added to the routine abdominal and pelvic MR examination for all patients imaged at our institution. A total of 21 patients (12 men and 9 women; mean age 55±6.3SD, range: 39–74 years) with known gastric malignancy were referred to our MR unit. All MRI examinations were performed using a 1.5-T MRI scanner (Magnetom Avanto, Siemens Healthcare). The evaluation of the DW-MRI examinations was made by radiologists’ consensus. Changes in the signal intensity of the lesions were determined by their appearance in images at b=50, 400, and 800 s/mm2 and in ADC maps. Results were compared with histopathological findings. Results: All of the gastric tumors in this study showed high signal intensity in DW-MRI and low signal intensity in ADC maps. Mean ADC values for gastric tumor and normal gastric wall were 0.892±0.23 SD mm2/s and 1.453±0.35 SD mm2/s respectively. The mean ADC values of gastric tumors were significantly lower than that of the normal gastric wall. Conclusion: DW-MRI and ADC values together can successfully differentiate gastric tumors from normal gastric wall. PMID:25610124

  15. Direct Portal Vein Thrombosis Visualization with T2*-Weighted Magnetic Resonance Imaging

    PubMed Central

    Li, Chuanming; Hu, Alice; Haacke, Mark; Wang, Jian; Zhao, Jun; Zhou, Daiquan

    2013-01-01

    BACKGROUND AND PURPOSE: To investigate the feasibility of direct magnetic resonance portal vein thrombosis (PVT) visualization with T2*-weighted imaging (T2*WI) without contrast agent. METHODS: Thirty patients with PVT were included in this study. All of them were imaged with contrast-enhanced CT (CE-CT) as well as non-contrast MRI T1, T2 and T2*WI. Imaging data was independently analyzed by two experienced radiologists. T2*WI of all PVT was compared slice-by-slice with each of the comparison sequences (T1WI, T2WI and CE-CT) on the following categories: the location, size, boundary, and conspicuity of thrombus and portal veins. RESULTS: The average score of PVT visualization in T2*WI was higher than T1WI and T2WI in location, size, boundary and conspicuity (t = 7.54 - 84.16, P<0.05), and higher than CE-CT in boundary and conspicuity (t = 3.03- 6.98, P<0.05). For portal vein visualization, there was no significant score difference in left, middle and right portal veins between CE-CT and T2*WI (t = -1.76- 1.35, P>0.05). CONCLUSIONS: Our results suggest T2*WI can characterize PVT accurately with high quality without the use of intravenous contrast agents. PMID:24046533

  16. Electromagnet weight reduction in a magnetic levitation system for contactless delivery applications.

    PubMed

    Hong, Do-Kwan; Woo, Byung-Chul; Koo, Dae-Hyun; Lee, Ki-Chang

    2010-01-01

    This paper presents an optimum design of a lightweight vehicle levitation electromagnet, which also provides a passive guide force in a magnetic levitation system for contactless delivery applications. The split alignment of C-shaped electromagnets about C-shaped rails has a bad effect on the lateral deviation force, therefore, no-split positioning of electromagnets is better for lateral performance. This is verified by simulations and experiments. This paper presents a statistically optimized design with a high number of the design variables to reduce the weight of the electromagnet under the constraint of normal force using response surface methodology (RSM) and the kriging interpolation method. 2D and 3D magnetostatic analysis of the electromagnet are performed using ANSYS. The most effective design variables are extracted by a Pareto chart. The most desirable set is determined and the influence of each design variable on the objective function can be obtained. The generalized reduced gradient (GRG) algorithm is adopted in the kriging model. This paper's procedure is validated by a comparison between experimental and calculation results, which shows that the predicted performance of the electromagnet designed by RSM is in good agreement with the simulation results.

  17. Electromagnet Weight Reduction in a Magnetic Levitation System for Contactless Delivery Applications

    PubMed Central

    Hong, Do-Kwan; Woo, Byung-Chul; Koo, Dae-Hyun; Lee, Ki-Chang

    2010-01-01

    This paper presents an optimum design of a lightweight vehicle levitation electromagnet, which also provides a passive guide force in a magnetic levitation system for contactless delivery applications. The split alignment of C-shaped electromagnets about C-shaped rails has a bad effect on the lateral deviation force, therefore, no-split positioning of electromagnets is better for lateral performance. This is verified by simulations and experiments. This paper presents a statistically optimized design with a high number of the design variables to reduce the weight of the electromagnet under the constraint of normal force using response surface methodology (RSM) and the kriging interpolation method. 2D and 3D magnetostatic analysis of the electromagnet are performed using ANSYS. The most effective design variables are extracted by a Pareto chart. The most desirable set is determined and the influence of each design variable on the objective function can be obtained. The generalized reduced gradient (GRG) algorithm is adopted in the kriging model. This paper’s procedure is validated by a comparison between experimental and calculation results, which shows that the predicted performance of the electromagnet designed by RSM is in good agreement with the simulation results. PMID:22163572

  18. Perfusion-weighted magnetic resonance imaging detects recurrent isolated vertigo caused by cerebral hypoperfusion.

    PubMed

    Xu, Xiaowei; Jiang, Li; Luo, Man; Li, Jiaoxing; Li, Weidong; Sheng, Wenli

    2015-06-01

    The etiology of isolated vertigo has been a substantial diagnostic challenge for both neurologists and otolaryngologists. This study was designed to detect recurrent isolated vertigo due to cerebral hypoperfusion using perfusion-weighted magnetic resonance imaging (PWI). We recruited isolated vertigo patients whose clinical condition was suspected to be caused by hypodynamics of the brain; these individuals formed the case group. We generated two additional groups: a negative group composed of vertigo patients whose symptoms were caused by problems associated with the ear and a healthy control group. Each subject underwent PWI, and seven regions of interest (ROIs) were chosen. The relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT) were obtained from each ROI. We further calculated the absolute difference of relative parameter values between two mirrored ROIs. The significant difference in the relative MTT from the mirrored cerebellar ROI (|rMTTleft-right|) of the case group was larger than those from the negative and healthy control groups (p = 0.026 and p = 0.038, respectively). Signal differences in |rrCBVleft-right| and |rrCBFleft-right| were not found among the three groups. In summary, disequilibrium in the rMTT of the bilateral cerebellum in the case group implied that hypoperfusion of the posterior circulation could trigger recurrent isolated vertigo and could be shown efficiently using PWI.

  19. Graphene oxide based theranostic platform for T1-weighted magnetic resonance imaging and drug delivery.

    PubMed

    Zhang, Mengxin; Cao, Yuhua; Chong, Yu; Ma, Yufei; Zhang, Hailu; Deng, Zongwu; Hu, Chunhong; Zhang, Zhijun

    2013-12-26

    Magnetic resonance imaging (MRI) is a powerful and widely used clinical technique in cancer diagnosis. MRI contrast agents (CAs) are often used to improve the quality of MRI-based diagnosis. In this work, we developed a positive T1 MRI CA based on graphene oxide (GO)-gadolinium (Gd) complexes. In our strategy, diethylenetriaminepentaacetic acid (DTPA) is chemically conjugated to GO, followed by Gd(III) complexation, to form a T1 MRI CA (GO-DTPA-Gd). We have demonstrated that the GO-DTPA-Gd system significantly improves MRI T1 relaxivity and leads to a better cellular MRI contrast effect than Magnevist, a commercially used CA. Next, an anticancer drug, doxorubicin (DOX), was loaded on the surface of GO sheets via physisorption. Thus-prepared GO-DTPA-Gd/DOX shows significant cytotoxicity to the cancer cells (HepG2). This work provides a novel strategy to build a GO-based theranostic nanoplatform with T1-weighted MRI, fluorescence imaging, and drug delivery functionalities.

  20. Quantitative magnetic resonance imaging of the brain in survivors of very low birth weight

    PubMed Central

    Abernethy, L; Palaniappan, M; Cooke, R

    2002-01-01

    Background: Children who survive very low birth weight (VLBW) without major disability have a high prevalence of learning difficulty, attention deficit, and dyspraxia. Aims: To determine whether learning difficulty in children with VLBW is associated with structural brain abnormalities. Methods: A total of 87 children (aged 15–16 years) with a history of VLBW (<1500 g) and eight age matched full term controls have been studied with detailed magnetic resonance brain scans. Volume measurements of the caudate nuclei and hippocampal formations were made. Results: Scans in 42.5% of the children showed evidence of perinatal brain injury. There was no significant difference in IQ, dyspraxia, or attention deficit between children with qualitatively normal and abnormal scans. However, quantitative volumetric analysis showed that children with a low IQ had smaller volume measurements for the right caudate nucleus and left hippocampus, and a smaller hippocampal ratio (left volume:right volume) than those with normal IQ. Conclusion: Data suggest that learning disorder, attention deficit, and dyspraxia in children who survive VLBW do not correlate with conventional markers of perinatal brain injury, and may be related to global brain growth and the development of key structures, such as the caudate nuclei and hippocampal formations. PMID:12243993

  1. Anomalous diffusion of brain metabolites evidenced by diffusion-weighted magnetic resonance spectroscopy in vivo

    PubMed Central

    Marchadour, Charlotte; Brouillet, Emmanuel; Hantraye, Philippe; Lebon, Vincent; Valette, Julien

    2012-01-01

    Translational displacement of molecules within cells is a key process in cellular biology. Molecular motion potentially depends on many factors, including active transport, cytosol viscosity and molecular crowding, tortuosity resulting from cytoskeleton and organelles, and restriction barriers. However, the relative contribution of these factors to molecular motion in the cytoplasm remains poorly understood. In this work, we designed an original diffusion-weighted magnetic resonance spectroscopy strategy to probe molecular motion at subcellular scales in vivo. This led to the first observation of anomalous diffusion, that is, dependence of the apparent diffusion coefficient (ADC) on the diffusion time, for endogenous intracellular metabolites in the brain. The observed increase of the ADC at short diffusion time yields evidence that metabolite motion is characteristic of hindered random diffusion rather than active transport, for time scales up to the dozen milliseconds. Armed with this knowledge, data modeling based on geometrically constrained diffusion was performed. Results suggest that metabolite diffusion occurs in a low-viscosity cytosol hindered by ∼2-μm structures, which is consistent with known intracellular organization. PMID:22929443

  2. Assessment of allograft function using diffusion-weighted magnetic resonance imaging in kidney transplant patients.

    PubMed

    Kaul, Anupma; Sharma, Raj Kumar; Gupta, Rakesh Kumar; Lal, Hira; Yadav, Abhishek; Bhadhuria, Dharmendra; Prasad, Narayan; Gupta, Amit

    2014-11-01

    Developing a non-invasive method such as diffusion-weighted magnetic resonance imaging (DWMRI) could be used as a feasible and reproducible modality in the differential diagnosis of allograft dysfunction. We assessed the functional status of the renal allograft by DWMRI and its applicability in assessment of graft dysfunction on all end-stage renal transplant patients who attained normal renal function on the 7th day post-transplantation. Follow-up imaging of the recipient allograft was performed at the end of 90 and 180 days and in case of graft dysfunction. Kidney biopsies were performed to correlate with the corresponding MRI. The apparent diffusion coefficient (ADC) maps of the cortex and medulla were obtained by studying the DWMRI. The ADC values were significantly lower in the medulla compared with the cortex in normal donor kidneys and normally functioning transplanted kidneys, while they decreased significantly when rejection occurred. The reduction in ADC values occurred both in the cortex and in the medulla, and correlated with the degree of rejection on the kidney biopsies. The ADC values increased significantly during the recovery from rejection. We conclude that DWMRI can be beneficial in the diagnosis and follow-up of transplant patients during acute rejection.

  3. Analysis of partial body weight support during treadmill and overground walking of children with cerebral palsy.

    PubMed

    Matsuno, Vânia M; Camargo, Muriel R; Palma, Gabriel C; Alveno, Diego; Barela, Ana Maria F

    2010-01-01

    to analyze the spatial-temporal characteristics and joint angles during overground walking without body weight support (BWS) and with 0% and 30% BWS, and during treadmill walking with the same BWS in children with cerebral palsy. six children with hemiplegic and spastic cerebral palsy (7.70 ± 1.04 years old) were videotaped during overground walking at a comfortable speed with no BWS, with 0% and 30% BWS, and during treadmill walking with 0% and 30% BWS. Reflective markers were placed over main bony landmarks in both body sides to register the coordinates "x", "y", "z". during overground walking, children walked faster and presented longer and faster strides, longer duration of single-stance and swing periods, and shorter duration of double-stance period, than treadmill walking, regardless of BWS use. The hip was the only joint that presented a difference between body sides and experimental conditions; i.e. range of motion (ROM) was reduced in the plegic side when compared to the nonplegic side, and during overground walking without BWS when compared to 30% BWS. children with hemiplegic and spastic cerebral palsy were able to walk overground and on a treadmill with different percentages of BWS, and their performance was superior during overground walking, regardless of BWS use.

  4. Overground body-weight-supported gait training for children and youth with neuromuscular impairments.

    PubMed

    Kurz, Max J; Stuberg, Wayne; Dejong, Stacey; Arpin, David J

    2013-08-01

    The aim of this investigation was to determine if body-weight-supported (BWS) overground gait training has the potential to improve the walking abilities of children and youth with childhood onset motor impairments and intellectual disabilities. Eight participants (mean age of 16.3 years) completed 12 weeks of BWS overground gait training that was performed two times a week. BWS was provided during the training sessions by an overhead harness system that rolls overground. There was a significant improvement in the preferred walking speed after the training (p < .01; pre = 0.51 ± 0.2 m/s; post = 0.67 ± 0.3 m/s; Cohen's d = 0.80) and cadence (p = .04; pre = 37 ± 7 steps/min; post = 43 ± 8 steps/min; Cohen's d = 0.94). Our results indicate that overground BWS gait training may be an effective treatment strategy for improving the preferred walking speed of children and youth with motor impairments.

  5. Use of multicriteria decision analysis to support weight of evidence evaluation.

    PubMed

    Linkov, Igor; Welle, Paul; Loney, Drew; Tkachuk, Alex; Canis, Laure; Kim, J B; Bridges, Todd

    2011-08-01

    Weight of evidence (WOE) methods are key components of ecological and human health risk assessments. Most WOE applications rely on the qualitative integration of diverse lines of evidence (LOE) representing impact on ecological receptors and humans. Recent calls for transparency in assessments and justifiability of management decisions are pushing the community to consider quantitative methods for integrated risk assessment and management. This article compares and contrasts the type of information required for application of individual WOE techniques and the outcomes that they provide in ecological risk assessment and proposes a multicriteria decision analysis (MCDA) framework for integrating individual LOE in support of management decisions. The use of quantitative WOE techniques is illustrated for a hypothetical but realistic case study of selecting remedial alternatives at a contaminated aquatic site. Use of formal MCDA does not necessarily eliminate biases and judgment calls necessary for selecting remedial alternatives, but allows for transparent evaluation and fusion of individual LOE. It also provides justifiable methods for selecting remedial alternatives consistent with stakeholder and decision-maker values. © 2011 Society for Risk Analysis.

  6. Walking with robot assistance: the influence of body weight support on the trunk and pelvis kinematics.

    PubMed

    Swinnen, Eva; Baeyens, Jean-Pierre; Knaepen, Kristel; Michielsen, Marc; Hens, Gerrit; Clijsen, Ron; Goossens, Maggie; Buyl, Ronald; Meeusen, Romain; Kerckhofs, Eric

    2015-05-01

    The goal was to assess in healthy participants the three-dimensional kinematics of the pelvis and the trunk during robot-assisted treadmill walking (RATW) at 0%, 30% and 50% body weight support (BWS), compared with treadmill walking (TW). 18 healthy participants walked (2 kmph) on a treadmill with and without robot assistance (Lokomat; 60% guidance force; 0%, 30% and 50% BWS). After an acclimatisation period (four minutes), trunk and pelvis kinematics were registered in each condition (Polhemus Liberty [240 Hz]). The results were analysed using a repeated measures analysis of variance with Bonferroni correction, with the level of suspension as within-subject factor. During RATW with BWS, there were significantly (1) smaller antero-posterior and lateral translations of the trunk and the pelvis; (2) smaller antero-posterior flexion and axial rotation of the trunk; (3) larger lateral flexion of the trunk; and (4) larger antero-posterior tilting of the pelvis compared with TW. There are significant differences in trunk and pelvis kinematics in healthy persons during TW with and without robot assistance. These data are relevant in gait rehabilitation, relating to normal balance regulation. Additional research is recommended to further assess the influence of robot assistance on human gait. The trunk and pelvis moves in a different way during walking with robot assistance. The data suggest that the change in movement is due to the robot device and the harness of the suspension system more than due to the level of suspension itself.

  7. Body weight support during robot-assisted walking: influence on the trunk and pelvis kinematics.

    PubMed

    Swinnen, Eva; Baeyens, Jean-Pierre; Hens, Gerrit; Knaepen, Kristel; Beckwée, David; Michielsen, Marc; Clijsen, Ron; Kerckhofs, Eric

    2015-01-01

    Efficacy studies concerning robot assisted gait rehabilitation showed limited clinical benefits. A changed kinematic pattern might be responsible for this. Little is known about the kinematics of the trunk and pelvis during robot assisted treadmill walking (RATW). The aim of this study was to assess the trunk and pelvis kinematics of healthy subjects during RATW, with different amounts of body weight support (BWS) compared to regular treadmill walking (TW). Eighteen healthy participants walked on a treadmill, while kinematics were registered by an electromagnetic tracking device. Hereafter, the kinematics of pelvis and trunk were registered during RATW (guidance force 30%) with 0%, 30% and 50% BWS. Compared to TW, RATW showed a decrease in the following trunk movements: axial rotation, anteroposterior flexion, lateral and anteroposterior translation. Besides, a decrease in lateral tilting and all translation of the pelvis was found when comparing RATW with TW. Furthermore, the anteroposterior tilting of the pelvis increased during RATW. In general, there was a decrease in trunk and pelvis movement amplitude during RATW compared with regular TW. Though, it is not known if these changes are responsible for the limited efficacy of robot assisted gait rehabilitation. Further research is indicated.

  8. Treadmill training with partial body weight support after stroke: a review.

    PubMed

    Hesse, Stefan

    2008-01-01

    Restoration and improvement of gait after stroke are major aspects of neurorehabilitation. Mobilization out of the bed into the wheelchair and verticalisation with the help of a standing frame are first steps. With the patient cardiovascular stable, gait restoration is put on the agenda. Instead of tone-inhibiting and gait preparatory maneuvers, patients should practice complex gait cycles repetitively. Treadmill training with partial body weight support enables the harness-secured patients to practice numerous steps assisted by two or three therapists. In controlled studies, it proved equally effective as walking on the floor. Gait machines, as the Lokomat or the Gait Trainer GTI, intend to relieve the strenuous effort for the therapists. For the GTI, several controlled trials showed a superior effect in acute stroke patients with respect to walking ability and velocity. For the ambulatory patient, aerobic treadmill training is effective to improve speed and endurance without worsening gait quality. Belt velocity and inclination are gradually increased so that the patients reach a predefined target heart rate. On the belt, patients walk more symmetrically, and higher velocities result in a facilitation of paretic muscles and render gait more efficient. In summary, gait rehabilitation has seen dramatic changes over the last years. More is to be expected.

  9. Support Vector Machine Classification of Major Depressive Disorder Using Diffusion-Weighted Neuroimaging and Graph Theory

    PubMed Central

    Sacchet, Matthew D.; Prasad, Gautam; Foland-Ross, Lara C.; Thompson, Paul M.; Gotlib, Ian H.

    2015-01-01

    Recently, there has been considerable interest in understanding brain networks in major depressive disorder (MDD). Neural pathways can be tracked in the living brain using diffusion-weighted imaging (DWI); graph theory can then be used to study properties of the resulting fiber networks. To date, global abnormalities have not been reported in tractography-based graph metrics in MDD, so we used a machine learning approach based on “support vector machines” to differentiate depressed from healthy individuals based on multiple brain network properties. We also assessed how important specific graph metrics were for this differentiation. Finally, we conducted a local graph analysis to identify abnormal connectivity at specific nodes of the network. We were able to classify depression using whole-brain graph metrics. Small-worldness was the most useful graph metric for classification. The right pars orbitalis, right inferior parietal cortex, and left rostral anterior cingulate all showed abnormal network connectivity in MDD. This is the first use of structural global graph metrics to classify depressed individuals. These findings highlight the importance of future research to understand network properties in depression across imaging modalities, improve classification results, and relate network alterations to psychiatric symptoms, medication, and comorbidities. PMID:25762941

  10. Support vector machine classification of major depressive disorder using diffusion-weighted neuroimaging and graph theory.

    PubMed

    Sacchet, Matthew D; Prasad, Gautam; Foland-Ross, Lara C; Thompson, Paul M; Gotlib, Ian H

    2015-01-01

    Recently, there has been considerable interest in understanding brain networks in major depressive disorder (MDD). Neural pathways can be tracked in the living brain using diffusion-weighted imaging (DWI); graph theory can then be used to study properties of the resulting fiber networks. To date, global abnormalities have not been reported in tractography-based graph metrics in MDD, so we used a machine learning approach based on "support vector machines" to differentiate depressed from healthy individuals based on multiple brain network properties. We also assessed how important specific graph metrics were for this differentiation. Finally, we conducted a local graph analysis to identify abnormal connectivity at specific nodes of the network. We were able to classify depression using whole-brain graph metrics. Small-worldness was the most useful graph metric for classification. The right pars orbitalis, right inferior parietal cortex, and left rostral anterior cingulate all showed abnormal network connectivity in MDD. This is the first use of structural global graph metrics to classify depressed individuals. These findings highlight the importance of future research to understand network properties in depression across imaging modalities, improve classification results, and relate network alterations to psychiatric symptoms, medication, and comorbidities.

  11. Elucidating the aberrant brain regions in bipolar disorder using T1-weighted/T2-weighted magnetic resonance ratio images.

    PubMed

    Ishida, Takuya; Donishi, Tomohiro; Iwatani, Jun; Yamada, Shinichi; Takahashi, Shun; Ukai, Satoshi; Shinosaki, Kazuhiro; Terada, Masaki; Kaneoke, Yoshiki

    2017-03-25

    Although diffusion tensor imaging (DTI) have revealed brain abnormalities in bipolar disorder (BD) subjects, DTI methods might not detect disease-related abnormalities in the white matter (WM) where nerve fibers are crossing. We investigated BD myelin-related abnormal brain regions in both gray matter and WM for 29 BD and 33 healthy control (HC) participants using T1-weighted (T1w)/T2-weighted (T2w) ratio images that increase myelin-related contrast irrespective of nerve fiber orientation. To check effect of the brain volume, the results were compared with those of voxel-based morphometry (VBM). We found significantly lower T1w/T2w signal intensity in broad WM regions in BD subjects, including the corpus callosum, corona radiata, internal capsule, middle cerebellar peduncle and cerebellum. Regional volume reduction was found in the WM bilateral posterior thalami and retrolenticular part of the internal capsules of BD subjects. We also performed tract-based spatial statistics (TBSS) in 25 BD and 24 HC participants and compared those for the T1w/T2w ratio images. Both methods detected the BD corpus callosum abnormality. Further, the ratio images detected the corona radiata and the cerebellar abnormality in BD. These results suggest that T1w/T2w ratio image analysis could take a complementary role with the DTI method in elucidating myelin-related abnormalities in BD.

  12. Design and Analyisi of a Self-centered Cold Mass Support for the MICE Coupling Magnet

    SciTech Connect

    Wang, Li; Pan, Heng; Wu, Hong; Li, S. Y.; Guo, Xing Long; Zheng, Shi Xian; Green, Michael A.

    2011-05-04

    The Muon Ionization Cooling Experiment (MICE) consists of eighteen superconducting solenoid coils in seven modules, which are magnetically hooked together since there is no iron to shield the coils and the return flux. The RF coupling coil (RFCC) module consists of a superconducting coupling solenoid mounted around four conventional conducting 201.25 MHz closed RF cavities. The coupling coil will produce up to a 2.2 T magnetic field on the centerline to keep the beam within the RF cavities. The peak magnetic force on the coupling magnet from other magnets in MICE is up to 500 kN in longitudinal direction, which will be transferred to the base of the RF coupling coil (RFCC) module through a cold mass support system. A self-centered double-band cold mass support system with intermediate thermal interruption is applied to the coupling magnet, and the design is introduced in detail in this paper. The thermal and structural analysis on the cold mass support assembly has been carried out using ANSYS. The present design of the cold mass support can satisfy with the stringent requirements for the magnet center and axis azimuthal angle at 4.2 K and fully charged.

  13. A longitudinal study of patients with cirrhosis treated with L-ornithine L-aspartate, examined with magnetization transfer, diffusion-weighted imaging and magnetic resonance spectroscopy.

    PubMed

    Grover, Vijay P B; McPhail, Mark J W; Wylezinska-Arridge, Marzena; Crossey, Mary M E; Fitzpatrick, Julie A; Southern, Louise; Saxby, Brian K; Cook, Nicola A; Cox, I Jane; Waldman, Adam D; Dhanjal, Novraj S; Bak-Bol, Aluel; Williams, Roger; Morgan, Marsha Y; Taylor-Robinson, Simon D

    2017-02-01

    The presence of overt hepatic encephalopathy (HE) is associated with structural, metabolic and functional changes in the brain discernible by use of a variety of magnetic resonance (MR) techniques. The changes in patients with minimal HE are less well documented. Twenty-two patients with well-compensated cirrhosis, seven of whom had minimal HE, were examined with cerebral 3 Tesla MR techniques, including T1- and T2-weighted, magnetization transfer and diffusion-weighted imaging and proton magnetic resonance spectroscopy sequences. Studies were repeated after a 4-week course of oral L-ornithine L-aspartate (LOLA). Results were compared with data obtained from 22 aged-matched healthy controls. There was no difference in mean total brain volume between patients and controls at baseline. Mean cerebral magnetization transfer ratios were significantly reduced in the globus pallidus and thalamus in the patients with cirrhosis irrespective of neuropsychiatric status; the mean ratio was significantly reduced in the frontal white matter in patients with minimal HE compared with healthy controls but not when compared with their unimpaired counterparts. There were no significant differences in either the median apparent diffusion coefficients or the mean fractional anisotropy, calculated from the diffusion-weighted imaging, or in the mean basal ganglia metabolite ratios between patients and controls. Psychometric performance improved in 50 % of patients with minimal HE following LOLA, but no significant changes were observed in brain volumes, cerebral magnetization transfer ratios, the diffusion weighted imaging variables or the cerebral metabolite ratios. MR variables, as applied in this study, do not identify patients with minimal HE, nor do they reflect changes in psychometric performance following LOLA.

  14. Improving anti-bullying laws and policies to protect youth from weight-based victimization: parental support for action.

    PubMed

    Puhl, R M; Suh, Y; Li, X

    2017-04-01

    Weight-based bullying is a prevalent problem among youth with overweight and obesity, but remains neglected in existing policy-level strategies to address youth bullying. Parental support is an influential catalyst motivating political will for policy decisions affecting youth, but has received limited research attention. To assess levels of, and predictors of, parental support for school-based policies and state/federal legal measures to address weight-based bullying in 2014 and 2015. Identical online questionnaires were completed by two independent national samples of parents in 2014 and 2015 (N = 1804). Parental support for all policy actions was high (at least 81%) and significantly increased from 2014 to 2015 for legal measures that would a) require state anti-bullying laws to add protections against weight-based bullying, and b) enact a federal anti-bullying law that includes weight-based bullying. These findings can inform policy discourse about remedies for youth bullying, and suggest that parental support for improved legal protections against weight-based bullying is present, consistent, and strong. © 2016 World Obesity Federation.

  15. The importance of parental beliefs and support for physical activity and body weights of children: a population-based analysis.

    PubMed

    Vander Ploeg, Kerry A; Maximova, Katerina; Kuhle, Stefan; Simen-Kapeu, Aline; Veugelers, Paul J

    2012-06-12

    To determine whether parental beliefs and support for physical activity (PA) are associated with normal-weight and overweight children's self-reported PA and body weight using a population-based approach. We analyzed cross-sectional survey data from 6,585 students and their parents in Alberta, Canada, collected in 2008 and 2010. Parental beliefs and support were collected through questions on "care about staying fit", "encourage PA" and "engage in PA with their child". Children's PA was self-reported. Body mass index was calculated from measured height and weight. We applied random effects models to assess: 1) the association of parental beliefs and support with children's PA; 2) differences in the associations for normal-weight and overweight children; 3) the association of parental beliefs and support with overweight. Parental care, encouragement, and engagement in PA were independently and positively associated with PA among both normal-weight and overweight children. Relative to children whose parents encouraged them "quite a lot", those whose parents encouraged them "very much" were 22% less likely to be overweight (OR=0.78, 95% CI: 0.68-0.89). Health promotion strategies that target parents to encourage and engage in PA with their children may increase activity levels and reduce overweight among children.

  16. THE ROLE OF TURBULENT MAGNETIC RECONNECTION IN THE FORMATION OF ROTATIONALLY SUPPORTED PROTOSTELLAR DISKS

    SciTech Connect

    Santos-Lima, R.; De Gouveia Dal Pino, E. M.; Lazarian, A.

    2012-03-01

    The formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the formation of a rotationally supported disk during the main protostellar accretion phase of low-mass stars. This has been known as the magnetic braking problem and the most investigated mechanism to alleviate this problem and help remove the excess of magnetic flux during the star formation process, the so-called ambipolar diffusion (AD), has been shown to be not sufficient to weaken the magnetic braking at least at this stage of the disk formation. In this work, motivated by recent progress in the understanding of magnetic reconnection in turbulent environments, we appeal to the diffusion of magnetic field mediated by magnetic reconnection as an alternative mechanism for removing magnetic flux. We investigate numerically this mechanism during the later phases of the protostellar disk formation and show its high efficiency. By means of fully three-dimensional MHD simulations, we show that the diffusivity arising from turbulent magnetic reconnection is able to transport magnetic flux to the outskirts of the disk progenitor at timescales compatible with the collapse, allowing the formation of a rotationally supported disk around the protostar of dimensions {approx}100 AU, with a nearly Keplerian profile in the early accretion phase. Since MHD turbulence is expected to be present in protostellar disks, this is a natural mechanism for removing magnetic flux excess and allowing the formation of these disks. This mechanism dismisses the necessity of postulating a hypothetical increase of the ohmic resistivity as discussed in the literature. Together with our earlier work which showed that magnetic flux removal from molecular cloud cores is very efficient, this work calls for reconsidering the relative role of AD in the processes of star

  17. T2-weighted four dimensional magnetic resonance imaging with result-driven phase sorting

    SciTech Connect

    Liu, Yilin; Yin, Fang-Fang; Cai, Jing; Czito, Brian G.; Bashir, Mustafa R.

    2015-08-15

    Purpose: T2-weighted MRI provides excellent tumor-to-tissue contrast for target volume delineation in radiation therapy treatment planning. This study aims at developing a novel T2-weighted retrospective four dimensional magnetic resonance imaging (4D-MRI) phase sorting technique for imaging organ/tumor respiratory motion. Methods: A 2D fast T2-weighted half-Fourier acquisition single-shot turbo spin-echo MR sequence was used for image acquisition of 4D-MRI, with a frame rate of 2–3 frames/s. Respiratory motion was measured using an external breathing monitoring device. A phase sorting method was developed to sort the images by their corresponding respiratory phases. Besides, a result-driven strategy was applied to effectively utilize redundant images in the case when multiple images were allocated to a bin. This strategy, selecting the image with minimal amplitude error, will generate the most representative 4D-MRI. Since we are using a different image acquisition mode for 4D imaging (the sequential image acquisition scheme) with the conventionally used cine or helical image acquisition scheme, the 4D dataset sufficient condition was not obviously and directly predictable. An important challenge of the proposed technique was to determine the number of repeated scans (N{sub R}) required to obtain sufficient phase information at each slice position. To tackle this challenge, the authors first conducted computer simulations using real-time position management respiratory signals of the 29 cancer patients under an IRB-approved retrospective study to derive the relationships between N{sub R} and the following factors: number of slices (N{sub S}), number of 4D-MRI respiratory bins (N{sub B}), and starting phase at image acquisition (P{sub 0}). To validate the authors’ technique, 4D-MRI acquisition and reconstruction were simulated on a 4D digital extended cardiac-torso (XCAT) human phantom using simulation derived parameters. Twelve healthy volunteers were involved

  18. T2-weighted four dimensional magnetic resonance imaging with result-driven phase sorting.

    PubMed

    Liu, Yilin; Yin, Fang-Fang; Czito, Brian G; Bashir, Mustafa R; Cai, Jing

    2015-08-01

    T2-weighted MRI provides excellent tumor-to-tissue contrast for target volume delineation in radiation therapy treatment planning. This study aims at developing a novel T2-weighted retrospective four dimensional magnetic resonance imaging (4D-MRI) phase sorting technique for imaging organ/tumor respiratory motion. A 2D fast T2-weighted half-Fourier acquisition single-shot turbo spin-echo MR sequence was used for image acquisition of 4D-MRI, with a frame rate of 2-3 frames/s. Respiratory motion was measured using an external breathing monitoring device. A phase sorting method was developed to sort the images by their corresponding respiratory phases. Besides, a result-driven strategy was applied to effectively utilize redundant images in the case when multiple images were allocated to a bin. This strategy, selecting the image with minimal amplitude error, will generate the most representative 4D-MRI. Since we are using a different image acquisition mode for 4D imaging (the sequential image acquisition scheme) with the conventionally used cine or helical image acquisition scheme, the 4D dataset sufficient condition was not obviously and directly predictable. An important challenge of the proposed technique was to determine the number of repeated scans (NR) required to obtain sufficient phase information at each slice position. To tackle this challenge, the authors first conducted computer simulations using real-time position management respiratory signals of the 29 cancer patients under an IRB-approved retrospective study to derive the relationships between NR and the following factors: number of slices (NS), number of 4D-MRI respiratory bins (NB), and starting phase at image acquisition (P0). To validate the authors' technique, 4D-MRI acquisition and reconstruction were simulated on a 4D digital extended cardiac-torso (XCAT) human phantom using simulation derived parameters. Twelve healthy volunteers were involved in an IRB-approved study to investigate the

  19. Detection of prostate cancer with magnetic resonance imaging: optimization of T1-weighted, T2-weighted, dynamic-enhanced T1-weighted, diffusion-weighted imaging apparent diffusion coefficient mapping sequences and MR spectroscopy, correlated with biopsy and histopathological findings.

    PubMed

    Aydin, Hasan; Kizilgöz, Volkan; Tatar, Idil Güneş; Damar, Cağri; Ugan, Ali Riza; Paker, Irem; Hekimoğlu, Baki

    2012-01-01

    The aim of this study was to optimize and predict the most efficient magnetic resonance imaging (MRI) sequences; T1-weighted (T1W), T2-weighted (T2W), dynamic contrast-enhanced (DCE) T1W, diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) mapping sequences and proton MR spectroscopy (H-MRS) for the detection of prostate cancer. After institutional review board approval and informed consent taken from all the patients, 40 patients with prostate cancer were included in this research. Two readers independently evaluated the results of T1W, T2W, DCE T1W, and DWI-ADC mapping sequences and proton H-MRS for the depiction of prostate cancer. Reference standard was the transrectal ultrasonography-guided biopsy and the surgical histopathological results. Statistical analysis was assessed by the Fisher exact t test, Wilcoxon signed rank test, variance analysis test with kappa (κ) values and receiver operating characteristics (ROC) curve for ADC values, choline (Cho)/citrate (Cit) and Cho+creatine (Cre)/Cit ratios for each observer. Based on both readers' results, sensitivity declined to 31% and specificity to 75% for the T1W sequence, sensitivity declined to 43% and specificity to 67% for the DCE T1W sequence, sensitivity declined to 46% and specificity to 68% for the T2W sequence, sensitivity declined to 29% and specificity to 82% for the DWI-ADC mapping; and specificity was 49% for the Cho/Cit and Cho+Cre/Cit ratios, sensitivity was 69% for the Cho/Cit ratio, and sensitivity was 70% for the Cho+Cre/Cit ratio for H-MRS. The T2W sequence and H-MRS presented significant statistical differences for the depiction of prostatic cancer (P < 0.05), the most efficient sequence to detect prostatic cancer was H-MRS: Cho+Cre/Cit and Cho/Cit ratios. Instead of using either sequences alone owing to low sensitivity and specificity rates, combined use of MRI techniques could easily improve the detection and staging of prostate cancer.

  20. Supporting the transition from weight loss to maintenance: development and optimisation of a face-to-face behavioural intervention component.

    PubMed

    Sainsbury, Kirby; Cleland, Claire L; Evans, Elizabeth H; Adamson, Ashley; Batterham, Alan; Dombrowski, Stephan U; Gellert, Paul; Hill, Moira; Kwasnicka, Dominika; Scott, Dawn; Sniehotta, Falko F; White, Martin; Araújo-Soares, Vera

    2017-01-01

    After weight loss, most individuals regain lost weight. Interventions to support the transition from successful loss to weight loss maintenance (WLM), regardless of the method of prior weight loss, are needed. The aims of this study were to (1) develop a face-to-face behavioural intervention session to support overweight and obese individuals who have recently lost a clinically significant amount of weight in the transition to WLM; (2) to assess the single-session intervention for acceptability and feasibility prior to its use in a larger, 12-month, multi-component trial; and (3) to optimise the intervention session for future use based on participant feedback. Participants with a Body Mass Index of ≥25 kg/m(2) prior to a ≥5% weight loss in the previous 12 months were recruited via the local government authority and community-based advertisements. Each attended the one-hour session with a trained facilitator, which focused on setting maintenance-relevant weight, eating, and physical activity goals. Semi-structured interviews were carried out immediately post-session to obtain feedback on the acceptability of this intervention component. Data were used to generate recommendations for changes to the session, which were discussed by the team, and used to optimise the session. Seventeen participants (13 female; median WL = 13%) were recruited. All participants evaluated the intervention session positively; 11 participants suggested improvements including reducing information provision in favour of greater focus on identifying and coping with barriers, and the inclusion of practical examples. The systematic refinement and optimisation process resulted in an acceptable and feasible face-to-face behavioural intervention session (described here), which will be tested as part of a multi-component intervention. We anticipate the session could be used to supplement existing support including online services, and has the potential to benefit people who have lost a

  1. Supporting the transition from weight loss to maintenance: development and optimisation of a face-to-face behavioural intervention component

    PubMed Central

    Sainsbury, Kirby; Cleland, Claire L.; Evans, Elizabeth H.; Adamson, Ashley; Batterham, Alan; Dombrowski, Stephan U.; Gellert, Paul; Hill, Moira; Kwasnicka, Dominika; Scott, Dawn; Sniehotta, Falko F.; White, Martin; Araújo-Soares, Vera

    2017-01-01

    ABSTRACT After weight loss, most individuals regain lost weight. Interventions to support the transition from successful loss to weight loss maintenance (WLM), regardless of the method of prior weight loss, are needed. The aims of this study were to (1) develop a face-to-face behavioural intervention session to support overweight and obese individuals who have recently lost a clinically significant amount of weight in the transition to WLM; (2) to assess the single-session intervention for acceptability and feasibility prior to its use in a larger, 12-month, multi-component trial; and (3) to optimise the intervention session for future use based on participant feedback. Participants with a Body Mass Index of ≥25 kg/m2 prior to a ≥5% weight loss in the previous 12 months were recruited via the local government authority and community-based advertisements. Each attended the one-hour session with a trained facilitator, which focused on setting maintenance-relevant weight, eating, and physical activity goals. Semi-structured interviews were carried out immediately post-session to obtain feedback on the acceptability of this intervention component. Data were used to generate recommendations for changes to the session, which were discussed by the team, and used to optimise the session. Seventeen participants (13 female; median WL = 13%) were recruited. All participants evaluated the intervention session positively; 11 participants suggested improvements including reducing information provision in favour of greater focus on identifying and coping with barriers, and the inclusion of practical examples. The systematic refinement and optimisation process resulted in an acceptable and feasible face-to-face behavioural intervention session (described here), which will be tested as part of a multi-component intervention. We anticipate the session could be used to supplement existing support including online services, and has the potential to benefit people who have

  2. Differential diagnosis of benign and malignant breast masses using diffusion-weighted magnetic resonance imaging.

    PubMed

    Min, Qinghua; Shao, Kangwei; Zhai, Lulan; Liu, Wei; Zhu, Caisong; Yuan, Lixin; Yang, Jun

    2015-02-07

    Diffusion-weighted magnetic resonance imaging (DW-MRI) is different from conventional diagnostic methods and has the potential to delineate the microscopic anatomy of a target tissue or organ. The purpose of our study was to evaluate the value of DW-MRI in the diagnosis of benign and malignant breast masses, which would help the clinical surgeon to decide the scope and pattern of operation. A total of 52 female patients with palpable solid breast masses received breast MRI scans using routine sequences, dynamic contrast-enhanced imaging, and diffusion-weighted echo-planar imaging at b values of 400, 600, and 800 s/mm(2), respectively. Two regions of interest (ROIs) were plotted, with a smaller ROI for the highest signal and a larger ROI for the overall lesion. Apparent diffusion coefficient (ADC) values were calculated at three different b values for all detectable lesions and from two different ROIs. The sensitivity, specificity, positive predictive value, and positive likelihood ratio of DW-MRI were determined for comparison with histological results. A total of 49 (49/52, 94.2%) lesions were detected using DW-MRI, including 20 benign lesions (two lesions detected in the same patient) and 29 malignant lesions. Benign lesion had a higher mean ADC value than their malignant counterparts, regardless of b value. According to the receiver operating characteristic (ROC) curve, the smaller-range ROI was more effective in differentiation between benign and malignant lesions. The area under the ROC curve was the largest at a b value of 800 s/mm(2). With a threshold ADC value at 1.23 × 10(-3) mm(2)/s, DW-MRI achieved a sensitivity of 82.8%, specificity of 90.0%, positive predictive value of 92.3%, and positive likelihood ratio of 8.3 for differentiating benign and malignant lesions. DW-MRI is an accurate diagnostic tool for differentiation between benign and malignant breast lesions, with an optimal b value of 800 s/mm(2). A smaller-range ROI focusing on the

  3. Determination of edema in porcine coronary arteries by T2 weighted cardiovascular magnetic resonance.

    PubMed

    Pedersen, Steen Fjord; Thrysøe, Samuel A; Paaske, William P; Thim, Troels; Falk, Erling; Ringgaard, Steffen; Kim, Won Yong

    2011-09-21

    Inflammation plays a pivotal role in all stages of atherosclerosis. Since edema is known to be an integral part of inflammation, a noninvasive technique that can identify edema in the coronary artery wall may provide unique information regarding plaque activity. In this study, we aimed to determine whether edema induced in porcine coronary arteries by balloon injury could be reliably detected by cardiovascular magnetic resonance (CMR) using a water sensitive T2-weighted short tau inversion recovery sequence (T2-STIR). We also aimed to compare these results to those of conventional T2-weighted (T2W) imaging. Edema was induced in the proximal left anterior descending (LAD) coronary artery wall in seven pigs by balloon injury. At baseline, and 1-10 days (average four) post injury, the proximal LAD was assessed by water sensitive T2-STIR and conventional T2W sequences in cross-sectional planes. CMR images were matched to histopathology, validated against Evans blue as a marker of increased vessel wall permeability, and correlated with the arterial amount of fibrinogen used as an edema surrogate marker. Post injury, the T2-STIR images of the injured LAD vessel wall showed a significant 72%, relative signal intensity (SI) increase compared with baseline (p = 0.028). Using a threshold value of SI 7 SD above the average SI of the myocardium, T2-STIR detected edema in the vessel wall (i.e. enhancement) with a sensitivity of 100 and a specificity of 71. Twelve out of the 14 (86%) T2-STIR images displaying coronary artery wall enhancement also showed Evans blue uptake in the corresponding histology. The relative signal intensity showed a linear correlation with the amount of fibrinogen detected on the corresponding histopathology (ρ = 0.750, p = 0.05). The conventional T2W images did not show significant changes in SI post injury. T2-STIR CMR enabled detection of coronary artery wall edema and could therefore be a non-invasive diagnostic tool for evaluation of inflammatory

  4. Martian Magnetization Vectors Estimated from Helbig Analysis Support a Reversing Core Dynamo

    NASA Astrophysics Data System (ADS)

    Phillips, J. D.

    2003-12-01

    Helbig (1963, Zeitschrift für Geophysik) developed the theory for estimating total magnetization vectors from the moments of measured magnetic component data. Helbig's theory has been tested successfully on aeromagnetic data for several terrestrial locations, where both the induced and remanent magnetizations of sources were known (Schmidt and Clark, 1997, Preview; 1998, Exploration Geophysics). Because Mars no longer has an inducing core field, application of Helbig analysis to the vector magnetic field measured by Mars Global Surveyor permits estimation of crustal remanent magnetization directions and strengths, paleomagnetic pole positions, and reversal characteristics of the extinct Martian core-field dynamo. The results provide an independent test of pole positions estimated from forward modeling (Arkani-Hamed, 2001, GRL) and of magnetization models estimated using inversion (Whaler and Purucker, 2003, The Leading Edge). A Helbig analysis of the n=90 Martian magnetic field model (Cain and others, 2003, JGR), evaluated at 150 km altitude, suggests that most of the stronger sources (average magnetization magnitudes > 4 A/m) have paleomagnetic pole positions within 50 degrees of 195E 50N. This region encloses Arkani-Hamed's (2001) estimated pole position of 230E 25N, based on his analysis of ten semi-isolated anomalies. A smaller number of strongly magnetized sources have pole positions that cluster within 40 degrees of 290E 5N. This cluster may represent either a secondary pole position or a preferred transition path during field reversals. Both normal and reversed magnetizations cluster at these pole positions, supporting the existence of a reversing core dynamo during the early history of Mars. When all estimated magnetic sources are included in the analysis, the weaker sources dominate, and the pole positions cluster along 35N and 35S latitudes. The corresponding source locations are concentrated along lines of longitude in areas of low magnetic intensity

  5. Effect of Body-Weight-Support Running on Lower-Limb Biomechanics.

    PubMed

    Neal, Michael; Fleming, Neil; Eberman, Lindsey; Games, Kenneth; Vaughan, Jeremiah

    2016-09-01

    Study Design Controlled laboratory study. Background Body-weight-support (BWS) running is increasing in popularity, despite limited evidence of its effects on running mechanics. Objectives To determine the effect of increasing BWS on lower-limb biomechanics during lower-body positive-pressure (LBPP) treadmill running. Methods Fourteen male recreational runners completed 15 randomized trials on an LBPP treadmill at 5 levels of BWS and 3 velocities (1-minute trials with 3-minute recovery). Knee and ankle kinematic data were recorded continuously via electrogoniometry. Synchronous in-shoe plantar-pressure data identified stride onset and quantified foot-segment forces. Data were recorded during the final 30 seconds of each trial and averaged over 10 consecutive stride cycles. Results Higher levels of BWS resulted in significantly (P<.001) increased stride duration, reduced stride frequency, and reduced ground contact time (GCT). In addition, normalized GCT (GCT/stride duration) was significantly reduced (P<.001), indicating increased flight time. Increasing BWS resulted in significant reductions (P<.001) in peak knee flexion and dorsiflexion and reduced overall knee and ankle range of motion during the stance phase. Conclusion Running on an LBPP treadmill alters lower-limb kinematics, resulting in reduced ankle and knee joint range of motion. In addition, increased BWS alters stride characteristics, resulting in shorter GCT and longer flight time. Clinicians must be aware of lower-limb kinematic alterations to provide safe and effective parameters for rehabilitation involving LBPP treadmills. J Orthop Sports Phys Ther 2016;46(9):784-793. doi:10.2519/jospt.2016.6503.

  6. Tail nerve electrical stimulation induces body weight-supported stepping in rats with spinal cord injury.

    PubMed

    Zhang, Shu-Xin; Huang, Fengfa; Gates, Mary; White, Jason; Holmberg, Eric G

    2010-03-30

    Walking or stepping has been considered the result from the activation of the central pattern generator (CPG). In most patients with spinal cord injury (SCI) the CPG is undamaged. To date, there are no noninvasive approaches for activating the CPG. Recently we developed a noninvasive technique, tail nerve electrical stimulation (TANES), which can induce positive hind limb movement of SCI rats. The purpose of this study is to introduce the novel technique and examine the effect of TANES on CPG activation. A 25 mm contusion injury was produced at spinal cord T10 of female, adult Long-Evans rats by using the NYU impactor device. Rats received TANES ( approximately 40 mA at 4 kHz) 7 weeks after injury. During TANES all injured rats demonstrated active body weight-supported stepping of hind limbs with left-right alternation and occasional front-hind coordination, resulting in significant, temporary increase in BBB scores (p<0.01). However, there is no response to TANES from rats with L2 transection, consistent with other reports that the CPG may be located at L1-2. S1 transection negatively implies the key role of TANES in CPG activation. The TANES not only renders paralyzed rats with a technique-induced ability to walk via activating CPG, but also is likely to be used for locomotor training. It has more beneficial effects for physical training over other training paradigms including treadmill training and invasive functional electrical stimulation. Therefore the TANES may have considerable potential for achieving improvement of functional recovery in animal models and a similar method may be suggested for human study. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  7. Limb contribution to increased self-selected walking speeds during body weight support in individuals poststroke

    PubMed Central

    Hurt, Christopher P.; Burgess, Jamie K.; Brown, David A.

    2015-01-01

    Individuals poststroke walk at faster self-selected speeds under some nominal level of body weight support (BWS) whereas nonimpaired individuals walk slower after adding BWS. The purpose of this study was to determine whether increases in self-selected overground walking speed under BWS conditions of individuals poststroke can be explained by changes in their paretic and nonparetic ground reaction forces (GRF). We hypothesize that increased self-selected walking speed, recorded at some nominal level of BWS, will relate to decreased braking GRFs by the paretic limb. We recruited ten chronic (>12 months post-ictus, 57.5±9.6 y.o.) individuals poststroke and eleven nonimpaired participants (53.3±4.1 y.o.). Participants walked overground in a robotic device, the KineAssist Walking and Balance Training System that provided varying degrees of BWS (0–20% in 5% increments) while individuals self-selected their walking speed. Self-selected walking speed and braking and propulsive GRF impulses were quantified. Out of ten poststroke individuals, eight increased their walking speed 13% (p=0.004) under some level of BWS (5% n=2, 10% n=3, 20% n=3) whereas nonimpaired controls did not change speed (p=0.470). In individuals poststroke, changes to self-selected walking speed were correlated with changes in paretic propulsive impulses (r=0.68, p=0.003) and nonparetic braking impulses (r=−0.80, p=0.006), but were not correlated with decreased paretic braking impulses (r=0.50 p=0.14). This investigation demonstrates that when individuals poststroke are provided with BWS and allowed to self-select their overground walking speed, they are capable of achieving faster speeds by modulating braking impulses on the nonparetic limb and propulsive impulses of the paretic limb. PMID:25770079

  8. Limb contribution to increased self-selected walking speeds during body weight support in individuals poststroke.

    PubMed

    Hurt, Christopher P; Burgess, Jamie K; Brown, David A

    2015-03-01

    Individuals poststroke walk at faster self-selected speeds under some nominal level of body weight support (BWS) whereas nonimpaired individuals walk slower after adding BWS. The purpose of this study was to determine whether increases in self-selected overground walking speed under BWS conditions of individuals poststroke can be explained by changes in their paretic and nonparetic ground reaction forces (GRF). We hypothesize that increased self-selected walking speed, recorded at some nominal level of BWS, will relate to decreased braking GRFs by the paretic limb. We recruited 10 chronic (>12 months post-ictus, 57.5±9.6 y.o.) individuals poststroke and eleven nonimpaired participants (53.3±4.1 y.o.). Participants walked overground in a robotic device, the KineAssist Walking and Balance Training System that provided varying degrees of BWS (0-20% in 5% increments) while individuals self-selected their walking speed. Self-selected walking speed and braking and propulsive GRF impulses were quantified. Out of 10 poststroke individuals, 8 increased their walking speed 13% (p=0.004) under some level of BWS (5% n=2, 10% n=3, 20% n=3) whereas nonimpaired controls did not change speed (p=0.470). In individuals poststroke, changes to self-selected walking speed were correlated with changes in paretic propulsive impulses (r=0.68, p=0.003) and nonparetic braking impulses (r=-0.80, p=0.006), but were not correlated with decreased paretic braking impulses (r=0.50 p=0.14). This investigation demonstrates that when individuals poststroke are provided with BWS and allowed to self-select their overground walking speed, they are capable of achieving faster speeds by modulating braking impulses on the nonparetic limb and propulsive impulses of the paretic limb.

  9. Application of a body-weight-supporting kite for sprint running.

    PubMed

    Kratky, Sascha; Müller, Erich

    2013-11-01

    Improvements in sprint performance at the top level require adaptations concerning force application because ground contact time diminishes with increasing velocity. Applied training methods and devices must provoke appropriate stimuli. A knowledge about positive and negative effects of these stimuli is vital for coaches. The purpose of this study was to determine the angle of attack and lifting and retarding forces of a novel sprint training device that supports the athlete's body weight (BW), thereby decreasing ground contact time during sprints. Three different kite sizes (1.10, 1.75, 2.25 m) were investigated. A bicycle was used to accelerate the National Aeronautics and Space Administration (NASA) parawings (NPW-120, NPW-150, and NPW-170) on an indoor track to acquire data at velocities between 6.5 and 10.5 m · s. During a 5-m interval of constant speed, the resultant force of the kite was recorded on a portable computer by a load cell. The angle of attack was determined by a high-speed camera, and the mean velocity in the 5-m sector was measured by a laser gauge. Lifting and retarding forces were derived from the resultant force and angle of attack. Quadratic regression equations for lifting and retarding forces, depending on the velocity, were calculated for all 3 NPWs. A clear difference (p < 0.001) depending on the kite size was revealed for lifting and retarding forces. These forces also indicated high correlation coefficients related to velocity (r > 0.98; p < 0.001), whereas the angle of attack remained almost constant across the entire velocity range in all NPWs, yielding a lift-to-drag ratio of 2.35. Because of the kite's small retarding forces, we recommend the application of the NPW during the high-speed phase of sprinting with lifting force probably counteracting adverse effects. By adding a towing system, the retarding force can be fine tuned, erased, or turned into overspeed assistance, thereby emphasizing BW support.

  10. Cerebral Effects of Targeted Temperature Management Methods Assessed by Diffusion-Weighted Magnetic Resonance Imaging.

    PubMed

    Grejs, Anders Morten; Gjedsted, Jakob; Pedersen, Michael; Birke-Sørensen, Hanne; Rauff-Mortensen, Andreas; Andersen, Kristian Kjær; Kirkegaard, Hans

    2016-12-01

    The aim of this randomized porcine study was to compare surface targeted temperature management (TTM) to endovascular TTM evaluated by cerebral diffusion-weighted magnetic resonance imaging (MRI): apparent diffusion coefficient (ADC), and by intracerebral/intramuscular microdialysis. It is well known that alteration in the temperature affects ADC, but the relationship between cerebral ADC values and the cooling method per se has not been established. Eighteen anesthetized 60-kg female swine were hemodynamically and intracerebrally monitored and subsequently subjected to a baseline MRI. The animals were then randomized into three groups: (1) surface cooling (n = 6) at 33.5°C using EMCOOLSpad(®), (2) endovascular cooling (n = 6) at 33.5°C using an Icy(®) cooling catheter with the CoolGard 3000(®), or (3) control (n = 6) at 38.5°C using a Bair Hugger™. The swine were treated with TTM for 6 hours followed by a second MRI examination, including ADC. Blood and microdialysate were sampled regularly throughout the experiment, and glucose, lactate, pyruvate, glycerol, and the lactate/pyruvate ratio did not differ among groups, neither intracerebrally nor intramuscularly. Surface cooling yielded a significantly lower median ADC than endovascular cooling: 714 (634; 804) × 10(-6) mm(2)/s versus 866 (828; 927) × 10(-6) mm(2)/s, (p < 0.05). The surface cooling ADC was lowered to a range usually attributed to cytotoxic edema and these low values could not be explained solely by the temperature effect per se. To what extent the ADC is fully reversible at rewarming is unknown and the clinical implications should be further investigated in clinical studies.

  11. Value of 3 Tesla diffusion-weighted magnetic resonance imaging for assessing liver fibrosis.

    PubMed

    Papalavrentios, Lavrentios; Sinakos, Emmanouil; Chourmouzi, Danai; Hytiroglou, Prodromos; Drevelegas, Konstantinos; Constantinides, Manos; Drevelegas, Antonios; Talwalkar, Jayant; Akriviadis, Evangelos

    2015-01-01

    Limited data are available regarding the role of magnetic resonance imaging (MRI), particularly the new generation 3 Tesla technology, and especially diffusion-weighted imaging (DWI) in predicting liver fibrosis. The aim of our pilot study was to assess the clinical performance of the apparent diffusion coefficient (ADC) of liver parenchyma for the assessment of liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). 18 patients with biopsy-proven NAFLD underwent DWI with 3 Tesla MRI. DWI was performed with single-shot echo-planar technique at b values of 0-500 and 0-1000 s/mm(2). ADC was measured in four locations in the liver and the mean ADC value was used for analysis. Staging of fibrosis was performed according to the METAVIR system. The median age of patients was 52 years (range 23-73). The distribution of patients in different fibrosis stages was: 0 (n=1), 1 (n=7), 2 (n=1), 3 (n=5), 4 (n=4). Fibrosis stage was poorly associated with ADC at b value of 0-500 s/mm(2) (r= -0.30, P=0.27). However it was significantly associated with ADC at b value of 0-1000 s/mm(2) (r= -0.57, P=0.01). For this b value (0-1000 s/mm(2)) the area under receiver-operating characteristic curve was 0.93 for fibrosis stage ≥3 and the optimal ADC cut-off value was 1.16 ×10(-3) mm(2)/s. 3 Tesla DWI can possibly predict the presence of advanced fibrosis in patients with NAFLD.

  12. Clinically Confirmed Stroke With Negative Diffusion-Weighted Imaging Magnetic Resonance Imaging

    PubMed Central

    Makin, Stephen D.J.; Doubal, Fergus N.; Dennis, Martin S.

    2015-01-01

    Background and Purpose— We sought to establish whether the presence (versus absence) of a lesion on magnetic resonance imaging (MRI) with diffusion weighting (DWI-MRI) at presentation with acute stroke is associated with worse clinical outcomes at 1 year. Methods— We recruited consecutive patients with a nondisabling ischemic stroke and performed DWI-MRI. Patients were followed up at 1 year to establish stroke recurrence (clinical or on MRI), cognitive impairment (Addenbrooke Cognitive Assessment Revised,<88) and modified Rankin Scale. Results— A median of 4 days post stroke, one third (76/264; 29%) of patients did not have a DWI lesion (95% confidence interval, 23%–35%). There was no statistically significant difference between those with and without a DWI lesion with respect to age or vascular risk factors. Patients without a lesion were more likely to be women or have previous stroke. At 1 year, 11 of 76 (14%) patients with a DWI-negative index stroke had a clinical diagnosis of recurrent stroke or transient ischemic attack, 33% had cognitive impairment (Addenbrooke Cognitive Assessment Revised <88), and 40% still had modified Rankin Scale >1, no different from DWI-positive patients; DWI-positive patients were more likely to have a new lesion on MRI (14%), symptomatic or asymptomatic, than DWI-negative patients (2%; P=0.02). Our data were consistent with 6 other studies (total n=976), pooled proportion of DWI-negative patients was 21% (95% confidence interval, 12%–32%). Conclusions— Nearly one third of patients with nondisabling stroke do not have a relevant lesion on acute DWI-MRI. Patients with negative DWI-MRI had no better prognosis than patients with a lesion. DWI-negative stroke patients should receive secondary prevention. PMID:26419965

  13. Feasibility of Behavioral Weight Loss Treatment Enhanced with Peer Support and Mobile Health Technology for Individuals with Serious Mental Illness.

    PubMed

    Aschbrenner, Kelly A; Naslund, John A; Shevenell, Megan; Mueser, Kim T; Bartels, Stephen J

    2016-09-01

    Effective and scalable lifestyle interventions are needed to address high rates of obesity in people with serious mental illness (SMI). This pilot study evaluated the feasibility of a behavioral weight loss intervention enhanced with peer support and mobile health (mHealth) technology for obese individuals with SMI. The Diabetes Prevention Program Group Lifestyle Balance intervention enhanced with peer support and mHealth technology was implemented in a community mental health setting. Thirteen obese individuals with SMI participated in a pre-post pilot study of the 24-week intervention. Feasibility was assessed by program attendance, and participant satisfaction and suggestions for improving the model. Descriptive changes in weight and fitness were also explored. Overall attendance amounted to approximately half (56 %) of weekly sessions. At 6-month follow-up, 45 % of participants had lost weight, and 45 % showed improved fitness by increasing their walking distance. Participants suggested a number of modifications to increase the relevance of the intervention for people with SMI, including less didactic instruction and more active learning, a simplified dietary component, more in depth technology training, and greater attention to mental health. The principles of standard behavioral weight loss treatment provide a useful starting point for promoting weight loss in people with SMI. However, adaptions to standard weight loss curricula are needed to enhance engagement, participation, and outcomes to respond to the unique challenges of individuals with SMI.

  14. Assessment of Weight Bias Among Pediatric Nurses and Clinical Support Staff Toward Obese Patients and Their Caregivers.

    PubMed

    Garcia, Janelle T; Amankwah, Ernest K; Hernandez, Raquel G

    2016-01-01

    The increasing burden of obesity is prevalent in the pediatric populations. Pediatric nurses are spending increasing amounts of time and effort caring for obese patients however no prior studies have explored how nurses perceive obese patients. The purpose of this study is to identify weight bias in pediatric nurses (RNs) and clinical support staff (CSS) working in a pediatric hospital setting. A convenience sample of RNs and CSS from an urban, pediatric hospital were surveyed using the Nurses' Attitudes toward Obesity and Obese Patients Scale (NATOOPS), which consists of 6 patient-care factors with an additional factor added to assess bias towards the patient's caregiver. Mean factor scores ≥50 indicated bias. Data were summarized using descriptive statistics and means were compared using independent t tests. Multivariate logistic regression models were used to determine the association between putative risk factors and weight bias. RNs and CSS (N=308) demonstrated weight bias toward obese patient characteristics (mean=61.9) and perceived controllability of obesity (mean=65.8). CSS felt negatively about their supportive roles in caring for obese patients (mean=52.5). Respondent weight status and professional title resulted in variability of biased attitudes. Race, employment status, number of obese patients cared for daily, and department were predictive of biased attitudes. Weight biased attitudes toward obese pediatric patients and their caregivers were found among RNs and CSS. Future qualitative research will assist in the understanding the factors that cause nurse weight bias. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Extremely long-lived magnetic excitations in supported Fe chains

    NASA Astrophysics Data System (ADS)

    Gauyacq, J. P.; Lorente, N.

    2016-07-01

    We report on a theoretical study of the lifetime of the first excited state of spin chains made of an odd number of Fe atoms on C u2N /Cu (100 ) . Yan, Choi, Burgess, Rolf-Pissarczyk, and Loth [Nat. Nanotech. 10, 40 (2015), 10.1038/nnano.2014.281] recently observed very long lifetimes in the case of F e3 chains. We consider the decay of the first excited state induced by electron-hole pair creation in the substrate. For a finite magnetic field, the two lowest-lying states in the chain have a quasi-Néel state structure. Decay from one state to the other strongly depends on the degree of entanglement of the local spins in the chain. The weak entanglement in the chain accounts for the long lifetimes that increase exponentially with chain length. Despite their apparently very different properties, the behavior of odd and even chains is governed by the same kind of phenomena, in particular entanglement effects. The present results account quite well for the lifetimes recently measured by Yan et al. on F e3 .

  16. Imposing spatio-temporal support in magnetic resonance angiographic imaging

    NASA Astrophysics Data System (ADS)

    Bones, Philip J.; Vafadar, Bahareh; Watts, Richard; Wu, Bing

    2010-08-01

    A method to improve time resolution in 3D contrast-enhanced magnetic resonance angiography (CE-MRA) is proposed. A temporal basis based on prior knowledge of the contrast flow dynamics is applied to a sequence of image reconstructions. In CE-MRA a contrast agent (gadolinium) is injected into a peripheral vein and MR data is acquired as the agent arrives in the arteries and then the veins of the region of clinical interest. The acquisition extends over several minutes. Information is effectively measured in 3D k-space (spatial frequency space) one line at-atime. That line may be along a Cartesian grid line in k-space, a radial line or a spiral trajectory. A complete acquisition comprises many such lines but in order to improve temporal resolution, reconstructions are made from only partial sets of k-space data. By imposing a basis for the temporal changes, based on prior expectation of the smoothness of the changes in contrast concentration with time, it is demonstrated that a significant reduction in artifacts caused by the under-sampling of k-space can be achieved. The basis is formed from a set of gamma variate functions. Results are presented for a simulated set of 2D spiral-sampled CE-MRA data.

  17. Physical Activity of Underweight, Normal Weight and Overweight Polish Adolescents: The Role of Classmate and Teacher Support in Physical Education

    ERIC Educational Resources Information Center

    Kantanista, Adam; Osinski, Wieslaw; Bronikowski, Michal; Tomczak, Maciej

    2013-01-01

    The aim of the study was to investigate the relationships of classmate and teacher support during physical education (PE) lessons on moderate-to-vigorous physical activity of 14-16 year-old students whom were underweight, normal weight and overweight. The cross-sectional sample for the study concerned data from 1702 girls and 1547 boys, recruited…

  18. Comparison of susceptibility-weighted and perfusion-weighted magnetic resonance imaging in the detection of penumbra in acute ischemic stroke.

    PubMed

    Luo, Song; Yang, Lijuan; Wang, Lijin

    2015-10-01

    To investigate detection of ischemic penumbra in stroke patients with acute cerebral infarction by susceptibility-weighted imaging (SWI) in comparison with perfusion-weighted imaging (PWI). This study included 18 stroke patients with acute infarction who underwent diffusion-weighted imaging (DWI), SWI, PWI, and magnetic resonance angiography (MRA) within 3 days after symptom onset. The Alberta Stroke Program Early CT Score (ASPECTS) was used to evaluate lesions on DWI, SWI, and PWI. DWI-SWI and DWI-PWI mismatches were calculated. The DWI-SWI mismatch was not significantly different from the DWI-mean transit time (MTT) mismatch (P=0.163) in evaluating ischemic penumbra. The susceptibility vessel sign (SVS) in SWI occurred in 11 (61%) of 18 patients with cerebral infarction. Stenosis or occlusion of the affected vessels was identified by MRA in 10 (91%) of the 11 SVS-positive patients. The SVS on SWI was significantly associated with the occurrence of damaged vessels or the presence of thrombus in the affected vessels (P=0.047). DWI-SWI mismatch is a good marker for evaluating ischemic penumbra in stroke patients with cerebral infarction. SWI can detect thrombus in the affected vessels, and may be useful for guiding intra-arterial thrombolytic therapy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  19. Decoherence-governed magnetic-moment dynamics of supported atomic objects

    NASA Astrophysics Data System (ADS)

    Gauyacq, Jean-Pierre; Lorente, Nicolás

    2015-11-01

    Due to the quantum evolution of molecular magnetic moments, the magnetic state of nanomagnets can suffer spontaneous changes. This process can be completely quenched by environment-induced decoherence. However, we show that for typical small supported atomic objects, the substrate-induced decoherence does change the magnetic-moment evolution but does not quell it. To be specific and to compare with experiment, we analyze the spontaneous switching between two equivalent magnetization states of atomic structures formed by Fe on Cu2N/Cu (1 0 0), measured by Loth et al (2012 Science 335 196-9). Due to the substrate-induced decoherence, the Rabi oscillations proper to quantum tunneling between magnetic states are replaced by an irreversible decay of long characteristic times leading to the observed stochastic magnetization switching. We show that the corresponding switching rates are small, rapidly decreasing with system’s size, with a 1/T thermal behavior and in good agreement with experiments. Quantum tunneling is recovered as the switching mechanism at extremely low temperatures below the μK range for a six-Fe-atom system and exponentially lower for larger atomic systems. The unexpected conclusion of this work is that experiments could detect the switching of these supported atomic systems because their magnetization evolution is somewhere between complete decoherence-induced stability and unobservably fast quantum-tunneling switching.

  20. Nanoparticle-supported and magnetically recoverable palladium (Pd) catalyst: a selective and sustainable oxidation protocol with high turnover number

    EPA Science Inventory

    A magnetic nanoparticle-supported ruthenium hydroxide catalyst was readily prepared from inexpensive starting materials and shown to catalyze hydration of nitriles with excellent yield in benign aqueous medium. Catalyst recovery using an external magnetic field, superior activity...

  1. Nanoparticle-supported and magnetically recoverable palladium (Pd) catalyst: a selective and sustainable oxidation protocol with high turnover number

    EPA Science Inventory

    A magnetic nanoparticle-supported ruthenium hydroxide catalyst was readily prepared from inexpensive starting materials and shown to catalyze hydration of nitriles with excellent yield in benign aqueous medium. Catalyst recovery using an external magnetic field, superior activity...

  2. The use of commitment techniques to support weight loss maintenance in obese adolescents.

    PubMed

    Kulendran, Myutan; King, Dominic; Schmidtke, Kelly Ann; Curtis, Claire; Gately, Paul; Darzi, Ara; Vlaev, Ivo

    2016-11-01

    Obesity is a rising problem in adolescents related to unhealthy behaviours. Commitment devises are one type of behavioural intervention that may help people change their behaviours. The current pilot trial tests whether commitment devices delivered via text message help adolescents maintain their recent weight loss. During a 12-week pilot trial, adolescents who attended a weight loss camp were randomly assigned to either received text messages that contained only information, i.e. advice, about weight loss management (n = 13) or asked for them to commit to following the same advise (n = 14). The BMI of the adolescents in the commitment group did not change. In contrast, the BMI of adolescents in the information group increased. A linear regression revealed that group was a significant predictor of BMI change. A logistic regression revealed that adolescents in the information group were nearly eight times more likely to regain weight than those in the commitment group. This is the first study with adolescents to show weight maintenance using a commitment device. The results suggest that commitment devices can help adolescents maintain their recent weight loss.

  3. An 8-Week Web-Based Weight Loss Challenge With Celebrity Endorsement and Enhanced Social Support: Observational Study

    PubMed Central

    Collins, Clare E; Morgan, Philip J; Callister, Robin

    2013-01-01

    Background Initial engagement and weight loss within Web-based weight loss programs may predict long-term success. The integration of persuasive Web-based features may boost engagement and therefore weight loss. Objective To determine whether an 8-week challenge within a commercial Web-based weight loss program influenced weight loss, website use, and attrition in the short term, when compared to the standard program. Methods De-identified data for participants (mean age 36.7±10.3 years; 86% female) who enrolled in the Biggest Loser Club (BLC) (n=952) and the BLC’s Shannan Ponton Fast Track Challenge (SC) for 8 weeks (n=381) were compared. The BLC program used standard evidence-based website features, with individualized calorie and exercise targets to facilitate a weight loss of 0.5-1 kg per week (–500kcal/day less than estimated energy expenditure). SC used the same website features but in addition promoted greater initial weight loss using a 1200 kcal/day energy intake target and physical activity energy expenditure of 600 kcal/day. SC used persuasive features to facilitate greater user engagement, including offering additional opportunities for social support (eg, webinar meetings with a celebrity personal trainer and social networking) endorsed by a celebrity personal trainer. Self-reported weekly weight records were used to determine weight change after 8 weeks. A primary analysis was undertaken using a generalized linear mixed model (GLMM) with all available weight records for all participants included. Dropout (participants who cancelled their subscription) and nonusage (participants who stopped using the Web-based features) attrition rates at 8 weeks were calculated. The number of participants who accessed each website feature and the total number of days each feature was used were calculated. The difference between attrition rates and website use for the two programs were tested using chi-square and Wilcoxon Rank Sum tests, respectively. Results

  4. Neural Responses to Visual Food Cues According to Weight Status: A Systematic Review of Functional Magnetic Resonance Imaging Studies

    PubMed Central

    Pursey, Kirrilly M.; Stanwell, Peter; Callister, Robert J.; Brain, Katherine; Collins, Clare E.; Burrows, Tracy L.

    2014-01-01

    Emerging evidence from recent neuroimaging studies suggests that specific food-related behaviors contribute to the development of obesity. The aim of this review was to report the neural responses to visual food cues, as assessed by functional magnetic resonance imaging (fMRI), in humans of differing weight status. Published studies to 2014 were retrieved and included if they used visual food cues, studied humans >18 years old, reported weight status, and included fMRI outcomes. Sixty studies were identified that investigated the neural responses of healthy weight participants (n = 26), healthy weight compared to obese participants (n = 17), and weight-loss interventions (n = 12). High-calorie food images were used in the majority of studies (n = 36), however, image selection justification was only provided in 19 studies. Obese individuals had increased activation of reward-related brain areas including the insula and orbitofrontal cortex in response to visual food cues compared to healthy weight individuals, and this was particularly evident in response to energy dense cues. Additionally, obese individuals were more responsive to food images when satiated. Meta-analysis of changes in neural activation post-weight loss revealed small areas of convergence across studies in brain areas related to emotion, memory, and learning, including the cingulate gyrus, lentiform nucleus, and precuneus. Differential activation patterns to visual food cues were observed between obese, healthy weight, and weight-loss populations. Future studies require standardization of nutrition variables and fMRI outcomes to enable more direct comparisons between studies. PMID:25988110

  5. Neural responses to visual food cues according to weight status: a systematic review of functional magnetic resonance imaging studies.

    PubMed

    Pursey, Kirrilly M; Stanwell, Peter; Callister, Robert J; Brain, Katherine; Collins, Clare E; Burrows, Tracy L

    2014-01-01

    Emerging evidence from recent neuroimaging studies suggests that specific food-related behaviors contribute to the development of obesity. The aim of this review was to report the neural responses to visual food cues, as assessed by functional magnetic resonance imaging (fMRI), in humans of differing weight status. Published studies to 2014 were retrieved and included if they used visual food cues, studied humans >18 years old, reported weight status, and included fMRI outcomes. Sixty studies were identified that investigated the neural responses of healthy weight participants (n = 26), healthy weight compared to obese participants (n = 17), and weight-loss interventions (n = 12). High-calorie food images were used in the majority of studies (n = 36), however, image selection justification was only provided in 19 studies. Obese individuals had increased activation of reward-related brain areas including the insula and orbitofrontal cortex in response to visual food cues compared to healthy weight individuals, and this was particularly evident in response to energy dense cues. Additionally, obese individuals were more responsive to food images when satiated. Meta-analysis of changes in neural activation post-weight loss revealed small areas of convergence across studies in brain areas related to emotion, memory, and learning, including the cingulate gyrus, lentiform nucleus, and precuneus. Differential activation patterns to visual food cues were observed between obese, healthy weight, and weight-loss populations. Future studies require standardization of nutrition variables and fMRI outcomes to enable more direct comparisons between studies.

  6. Family factors and social support in the developmental outcomes of very low-birth weight children.

    PubMed

    Hogan, D P; Park, J M

    2000-06-01

    This study used data that were representative of the normative population of all infants born in 1988 and were followed during the first 3 years of life. Large developmental delays and limitations in function were common among children weighing less than 1500 g at birth. Among very low-birth weight infants, minority status and living in a household headed by a single mother further worsen the disadvantages associated with a very low birth weight. Nor could the disadvantages associated with very low birth weight be accounted for by controls for other risk factors or buffering statuses and behaviors. Among all children (including those of very low birth weight) poverty, reliance on Medicaid and other government sources for health insurance, a history of risky behaviors, and inadequate prenatal care are the major risk factors for developmental delays, limitations in function, and impairment at birth. State program benefit levels have no obvious effects on child outcomes, taking into account participation in individual programs. An important finding in light of TANF is that maternal work, the use of child care, and the form and cost of child care did not influence developmental delay, limitation in function, or impairment, the outcomes that we were able to measure during the first 3 years of life. TANF eligibility requirements, however, may increase difficulty in obtaining prenatal and other medical services for mothers and children in need--factors shown here to be related strongly to increased risk of low birth weight and developmental delays, limitations, and impairments. Race and ethnicity, poverty status, and family structure are fundamental factors in early child development and function. Minority status, poverty, and single-parent households greatly increase the likelihood that a mother will engage in risky behaviors (smoking, alcohol use, illegal drug use) during pregnancy and receive inadequate prenatal care. Risky behaviors and inadequate prenatal care are

  7. Diffusion Weighted Magnetic Resonance Imaging Assessment of Blood Flow in the Microvasculature of Abdominal Organs

    NASA Astrophysics Data System (ADS)

    Truica, Loredana Sorina

    In this thesis, water diffusion in human liver and placenta is studied using diffusion weighted magnetic resonance imaging. For short, randomly oriented vascular segments, intravascular water motion is diffusion-like. For tissues with large vascular compartments the diffusion decay is bi-exponential with one component corresponding to diffusing water and the other to water in the microvasculature. This model, known as the intravoxel incoherent motion (IVIM) model, is seldom used with abdominal organs because of motion artifacts. This limitation was overcome for the experiments reported here by introducing: 1) parallel imaging, 2) navigator echo respiratory triggering (NRT), 3) a double echo diffusion sequence that inherently compensates for eddy current effects, 4) SPAIR fat suppression and 5) a superior approach to image analysis. In particular, the use of NRT allowed us to use a free breathing protocol instead of the previously required breath hold protocol. The resulting DWI images were of high quality and motion artifact free. Diffusion decays were measured over a larger portion of the decay than had previously been reported and the results are considerably better than those previously reported. For both studies, reliable measurements of the diffusion coefficient (D), pseudo-diffusion coefficient (D) and perfusion fraction (f), were obtained using a region of interest analysis as well as a pixel-by-pixel approach. To within experimental error, all patients had the same values of D (1.10 mum 2/ms +/- 0.16 mum2/ms), D* (46 mum2/ms +/- 17 mum2/ms) and f (44.0% +/- 6.9%) in liver and D (1.8 mum 2/ms +/- 0.2 mum2/ms), D* (30 mum 2/ms +/- 12 mmu2/ms), and f (40% +/- 6%) in the placenta. No dependence on gestational age was found for the placental study. Parametric maps of f and D* were consistent with blood flow patterns in both systems. The model worked well for both investigated organs even though their anatomical structures are quite different. A method for

  8. Role of diffusion-weighted magnetic resonance imaging in differentiating malignancies from benign ovarian tumors

    PubMed Central

    Fan, Xinhua; Zhang, Hongbin; Meng, Shuang; Zhang, Jing; Zhang, Chuge

    2015-01-01

    Objective: We conducted a case-control study to evaluate the diagnostic values of computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) in differentiating malignancies from benign ovarian tumors and a meta-analysis to further confirm our results on DW-MRI. Methods: Totally 64 patients pathologically confirmed as ovarian cancer were included in this study. CT scan and DWI-MRI were performed and analyzed to get compared with pathological results, thereby assessing their accuracy, sensitivity and specificity. Meta-analysis was conducted by database searching and strict eligibility criteria, using STATA 12.0 (Stata Corp, College Station, TX, USA) software. Results: The accuracy, sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of ovarian cancer in CT were 81.82%, 84.48%, 76.67%, 87.50% and 71.88%, respectively; those in DW-MRI were 89.77%, 93.10%, 83.33%, 91.53% and 86.21%, respectively. The Kappa coefficient of DW-MRI (K = 0.771) compared with pathological results was higher than CT (K = 0.602). The average apparent diffusion coefficient values of DW-MRI in diagnosis of benign and malignant ovarian tumors suggested statistically significant difference (1.325 ± 0.269×10-3 mm2/s vs. 0.878 ± 0.246×10-3 mm2/s, P < 0.001). Meta-analysis results showed that the combined sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio of DW-MRI in discriminating benign versus malignant ovarian tumors were 0.93, 0.88, 7.70, 0.08 and 101.24, respectively. The area under the summary receiver operating characteristic curve was 0.95. Conclusions: Both CT and DW-MRI were of great diagnostic value in differentiating malignancies from benign ovarian tumors, while DW-MRI was superior to CT with higher accuracy, sensitivity and specificity. PMID:26884905

  9. Dual-Enzyme-Loaded Multifunctional Hybrid Nanogel System for Pathological Responsive Ultrasound Imaging and T2-Weighted Magnetic Resonance Imaging.

    PubMed

    Wang, Xia; Niu, Dechao; Li, Pei; Wu, Qing; Bo, Xiaowan; Liu, Boji; Bao, Song; Su, Teng; Xu, Huixiong; Wang, Qigang

    2015-06-23

    A dual-enzyme-loaded multifunctional hybrid nanogel probe (SPIO@GCS/acryl/biotin-CAT/SOD-gel, or SGC) has been developed for dual-modality pathological responsive ultrasound (US) imaging and enhanced T2-weighted magnetic resonance (MR) imaging. This probe is composed of functionalized superparamagnetic iron oxide particles, a dual enzyme species (catalase and superoxide dismutase), and a polysaccharide cationic polymer glycol chitosan gel. The dual-modality US/MR imaging capabilities of the hybrid nanogel for responsive US imaging and enhanced T2-weighted MR imaging have been evaluated both in vitro and in vivo. These results show that the hybrid nanogel SGC can exhibit efficient dual-enzyme biocatalysis with pathological species for responsive US imaging. SGC also demonstrates increased accumulation in acidic environments for enhanced T2-weighted MR imaging. Further research on these nanogel systems may lead to the development of more efficient US/MR contrast agents.

  10. Fabrication of an Implant-Supported Orbital Prosthesis with Bar-Magnetic Attachment: A Clinical Report.

    PubMed

    Aalaei, Shima; Abolhassani, Abolhassan; Nematollahi, Fatemeh; Beyabanaki, Elaheh; Mangoli, Amir Ali

    2015-12-01

    Implant-supported craniofacial prostheses are made to restore defective areas in the face and cranium. This clinical report describes a technique for fabrication of an orbital prosthesis with three adjacent implants in the left lateral orbital rim of a 60-year-old woman. Selection of appropriate attachment system (individual magnetic abutments versus bar-clip attachment) for implant-supported orbital prostheses depends upon the position of implants. Bar-magnetic attachment has been selected as the retention mechanism in the present case.

  11. Fabrication of an Implant-Supported Orbital Prosthesis with Bar-Magnetic Attachment: A Clinical Report

    PubMed Central

    Aalaei, Shima; Abolhassani, Abolhassan; Nematollahi, Fatemeh; Beyabanaki, Elaheh; Mangoli, Amir Ali

    2015-01-01

    Implant-supported craniofacial prostheses are made to restore defective areas in the face and cranium. This clinical report describes a technique for fabrication of an orbital prosthesis with three adjacent implants in the left lateral orbital rim of a 60-year-old woman. Selection of appropriate attachment system (individual magnetic abutments versus bar-clip attachment) for implant-supported orbital prostheses depends upon the position of implants. Bar-magnetic attachment has been selected as the retention mechanism in the present case. PMID:27559354

  12. Application of comprehensive weight and both-branch fuzzy set in safety assessment of aerial ground support

    NASA Astrophysics Data System (ADS)

    Hu, Zongshun; Huang, Zhijie

    2017-04-01

    On the basis of constructing the safety assessment index system of aerial ground support, natural weight and variable weight theory are introduced according with the dynamic and fuzzy nature of the index. The weight of index can be calculated and adjusted to solve the problem effectively of reducing the risk grade of system because of some lower index weight being neutralized by others. Then using extensible method to make the connection normalized, and subordinate degree matrix of the positive and negative index fields to safety level is set up based on both-branch fuzzy model, in order to optimize and show the importance of the factor in the assessment system. Finally, characteristic value of system comprehensive connection number is calculated by characteristic formula, the assessment level of the system is determined. Index system and this method are applied to one aerial ground support of Jinan airport, results are rational and accurate. Reference basis is provided for deep development of safety assessment of aerial ground support.

  13. Computer-supported weight-based drug infusion concentrations in the neonatal intensive care unit.

    PubMed

    Giannone, Gay

    2005-01-01

    This article addresses the development of a computerized provider order entry (CPOE)-embedded solution for weight-based neonatal drug infusion developed during the transition from a legacy CPOE system to a customized application of a neonatal CPOE product during a hospital-wide information system transition. The importance of accurate fluid management in the neonate is reviewed. The process of tailoring the system that eventually resulted in the successful development of a computer application enabling weight-based medication infusion calculation for neonates within the CPOE information system is explored. In addition, the article provides guidelines on how to customize a vendor solution for hospitals with neonatal intensive care unit.

  14. Functional multiparametric magnetic resonance imaging of the kidneys using blood oxygen level dependent and diffusion-weighted sequences.

    PubMed

    Giannarini, Gianluca; Kessler, Thomas M; Roth, Beat; Vermathen, Peter; Thoeny, Harriet C

    2014-08-01

    Little data are available on noninvasive magnetic resonance imaging based assessment of renal function during upper urinary tract obstruction. We determined whether functional multiparametric kidney magnetic resonance imaging could monitor the treatment response in cases of acute unilateral upper urinary tract obstruction. Between January 2008 and January 2010, 18 patients with acute unilateral upper urinary tract obstruction due to calculi were prospectively enrolled to undergo kidney magnetic resonance imaging with conventional, blood oxygen level dependent and diffusion-weighted sequences upon emergency hospital admission and after release of obstruction. We assessed functional imaging parameters of obstructed and contralateral unobstructed kidneys derived from blood oxygen level dependent (apparent spin relaxation rate) and diffusion-weighted (total apparent diffusion coefficient, pure diffusion coefficient and perfusion fraction) sequences during acute upper urinary tract obstruction and after its release. During acute obstruction the apparent spin relaxation rate and perfusion fraction were lower in the cortex (p=0.020 and 0.031) and medulla (p=0.012 and 0.190, respectively) of obstructed kidneys compared to contralateral unobstructed kidneys. After obstruction release the apparent spin relaxation rate and perfusion fraction increased in the cortex (p=0.016 and 0.004) and medulla (p=0.071 and 0.044, respectively) of formerly obstructed kidneys to values similar to those in contralateral kidneys. Total apparent diffusion coefficient and pure diffusion coefficient values did not significantly differ between obstructed and contralateral unobstructed kidneys during or after obstruction. In our patients with acute unilateral upper urinary tract obstruction due to calculi functional kidney magnetic resonance imaging using blood oxygen level dependent and diffusion-weighted sequences enabled us to monitor pathophysiological changes in obstructed kidneys during

  15. Evaluation of Public Health Professionals' Capacity to Implement Environmental Changes Supportive of Healthy Weight

    ERIC Educational Resources Information Center

    Gantner, Leigh A.; Olson, Christine M.

    2012-01-01

    Community-based interventions to promote healthy weights by making environmental and policy changes in communities may be an important strategy in reversing the obesity epidemic. However, challenges faced by local public health professionals in facilitating effective environmental and policy change need to be better understood and addressed. To…

  16. Evaluation of Public Health Professionals' Capacity to Implement Environmental Changes Supportive of Healthy Weight

    ERIC Educational Resources Information Center

    Gantner, Leigh A.; Olson, Christine M.

    2012-01-01

    Community-based interventions to promote healthy weights by making environmental and policy changes in communities may be an important strategy in reversing the obesity epidemic. However, challenges faced by local public health professionals in facilitating effective environmental and policy change need to be better understood and addressed. To…

  17. Superconductive material and magnetic field for damping and levitation support and damping of cryogenic instruments

    NASA Technical Reports Server (NTRS)

    Dolgin, Benjamin P. (Inventor)

    1994-01-01

    A superconductive load bearing support without a mechanical contact and vibration damping for cryogenic instruments in space is presented. The levitation support and vibration damping is accomplished by the use of superconducting magnets and the 'Meissner' effect. The assembly allows for transfer of vibration energy away from the cryogenic instrument which then can be damped by the use of either an electronic circuit or conventional vibration damping mean.

  18. Investigation of field and diffusion time dependence of the diffusion-weighted signal at ultrahigh magnetic fields.

    PubMed

    Kunz, Nicolas; Sizonenko, Stéphane V; Hüppi, Petra S; Gruetter, Rolf; van de Looij, Yohan

    2013-10-01

    Over the last decade, there has been a significant increase in the number of high-magnetic-field MRI magnets. However, the exact effect of a high magnetic field strength (B0 ) on diffusion-weighted MR signals is not yet fully understood. The goal of this study was to investigate the influence of different high magnetic field strengths (9.4 T and 14.1 T) and diffusion times (9, 11, 13, 15, 17 and 24 ms) on the diffusion-weighted signal in rat brain white matter. At a short diffusion time (9 ms), fractional anisotropy values were found to be lower at 14.1 T than at 9.4 T, but this difference disappeared at longer diffusion times. A simple two-pool model was used to explain these findings. The model describes the white matter as a first hindered compartment (often associated with the extra-axonal space), characterized by a faster orthogonal diffusion and a lower fractional anisotropy, and a second restricted compartment (often associated with the intra-axonal space), characterized by a slower orthogonal diffusion (i.e. orthogonal to the axon direction) and a higher fractional anisotropy. Apparent T2 relaxation time measurements of the hindered and restricted pools were performed. The shortening of the pseudo-T2 value from the restricted compartment with B0 is likely to be more pronounced than the apparent T2 changes in the hindered compartment. This study suggests that the observed differences in diffusion tensor imaging parameters between the two magnetic field strengths at short diffusion time may be related to differences in the apparent T2 values between the pools. Copyright © 2013 John Wiley & Sons, Ltd.

  19. 'Are you still on that stupid diet?': women's experiences of societal pressure and support regarding weight loss, and attitudes towards health policy intervention.

    PubMed

    Whale, Katie; Gillison, Fiona B; Smith, Paula C

    2014-12-01

    This study investigated how people's attitudes and motivations towards losing weight are influenced by societal pressures surrounding weight loss, their interaction with the obesogenic environment and individuals' attitudes and motivations towards weight. Semi-structured qualitative interviews were conducted with 10 women currently attending commercial weight-loss programmes. Participants experienced conflicting messages regarding weight norms, with the media portraying powerful social norms relating to thinness and beauty, and changes to the food environment and interactions with family and friends commonly undermining weight-loss activities and promoting increased consumption. Providing social and environmental support for the behaviours needed to produce weight loss may need to be a primary focus for obesity policy.

  20. Ultrasmall water-soluble metal-iron oxide nanoparticles as T1-weighted contrast agents for magnetic resonance imaging.

    PubMed

    Zeng, Leyong; Ren, Wenzhi; Zheng, Jianjun; Cui, Ping; Wu, Aiguo

    2012-02-28

    Using an improved hydrolysis method of inorganic salts assisted with water-bath incubation, ultrasmall water-soluble metal-iron oxide nanoparticles (including Fe(3)O(4), ZnFe(2)O(4) and NiFe(2)O(4) nanoparticles) were synthesized in aqueous solutions, which were used as T(1)-weighted contrast agents for magnetic resonance imaging (MRI). The morphology, structure, MRI relaxation properties and cytotoxicity of the as-prepared metal-iron oxide nanoparticles were characterized, respectively. The results showed that the average sizes of nanoparticles were about 4 nm, 4 nm and 5 nm for Fe(3)O(4), ZnFe(2)O(4) and NiFe(2)O(4) nanoparticles, respectively. Moreover, the nanoparticles have good water dispersibility and low cytotoxicity. The MRI test showed the strong T(1)-weighted, but the weak T(2)-weighted MRI performance of metal-iron oxide nanoparticles. The high T(1)-weighted MRI performance can be attributed to the ultrasmall size of metal-iron oxide nanoparticles. Therefore, the as-prepared metal-iron oxide nanoparticles with good water dispersibility and ultrasmall size can have potential applications as T(1)-weighted contrast agent materials for MRI.

  1. PubMed-supported clinical term weighting approach for improving inter-patient similarity measure in diagnosis prediction.

    PubMed

    Chan, Lawrence Wc; Liu, Ying; Chan, Tao; Law, Helen Kw; Wong, S C Cesar; Yeung, Andy Ph; Lo, K F; Yeung, S W; Kwok, K Y; Chan, William Yl; Lau, Thomas Yh; Shyu, Chi-Ren

    2015-06-02

    Similarity-based retrieval of Electronic Health Records (EHRs) from large clinical information systems provides physicians the evidence support in making diagnoses or referring examinations for the suspected cases. Clinical Terms in EHRs represent high-level conceptual information and the similarity measure established based on these terms reflects the chance of inter-patient disease co-occurrence. The assumption that clinical terms are equally relevant to a disease is unrealistic, reducing the prediction accuracy. Here we propose a term weighting approach supported by PubMed search engine to address this issue. We collected and studied 112 abdominal computed tomography imaging examination reports from four hospitals in Hong Kong. Clinical terms, which are the image findings related to hepatocellular carcinoma (HCC), were extracted from the reports. Through two systematic PubMed search methods, the generic and specific term weightings were established by estimating the conditional probabilities of clinical terms given HCC. Each report was characterized by an ontological feature vector and there were totally 6216 vector pairs. We optimized the modified direction cosine (mDC) with respect to a regularization constant embedded into the feature vector. Equal, generic and specific term weighting approaches were applied to measure the similarity of each pair and their performances for predicting inter-patient co-occurrence of HCC diagnoses were compared by using Receiver Operating Characteristics (ROC) analysis. The Areas under the curves (AUROCs) of similarity scores based on equal, generic and specific term weighting approaches were 0.735, 0.728 and 0.743 respectively (p < 0.01). In comparison with equal term weighting, the performance was significantly improved by specific term weighting (p < 0.01) but not by generic term weighting. The clinical terms "Dysplastic nodule", "nodule of liver" and "equal density (isodense) lesion" were found the top three image

  2. Structural Magnetic Resonance Imaging Data Do Not Help Support DSM-5 Autism Spectrum Disorder Category

    ERIC Educational Resources Information Center

    Pina-Camacho, Laura; Villero, Sonia; Boada, Leticia; Fraguas, David; Janssen, Joost; Mayoral, Maria; Llorente, Cloe; Arango, Celso; Parellada, Mara

    2013-01-01

    This systematic review aims to determine whether or not structural magnetic resonance imaging (sMRI) data support the DSM-5 proposal of an autism spectrum disorder (ASD) diagnostic category, and whether or not classical DSM-IV autistic disorder (AD) and Asperger syndrome (AS) categories should be subsumed into it. The most replicated sMRI findings…

  3. Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds

    EPA Science Inventory

    A ruthenium (Ru) catalyst supported on magnetic nanoparticles (NiFe2O4) has been successfully synthesized and used for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The cata...

  4. Interdistrict Magnet High School Students' Perceived Social Support: An Exploratory Investigation

    ERIC Educational Resources Information Center

    LaRocco, Diana J.; Fitzgerald, Jessica

    2010-01-01

    Magnet high school attendance seems to lead to improved academic performance (Cobb, Bifulco, & Bell, 2009; U.S. Department of Education, 2008; Yu & Taylor, 1997). Likewise, perceived social support has been linked with positive outcomes for adolescents, including improved academic performance (Rosenfeld, Richman, & Bowen, 2000; Demaray & Malecki,…

  5. Magnetic silica supported palladium catalyst: synthesis of allyl aryl ethers in water

    EPA Science Inventory

    A simple and benign procedure for the synthesis of aryl allyl ethers has been developed using phenols, allyl acetates and magnetically recyclable silica supported palladium catalyst in water; performance of reaction in air and easy separation of the catalyst using an external mag...

  6. Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds

    EPA Science Inventory

    A ruthenium (Ru) catalyst supported on magnetic nanoparticles (NiFe2O4) has been successfully synthesized and used for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The cata...

  7. Magnetic silica supported palladium catalyst: synthesis of allyl aryl ethers in water

    EPA Science Inventory

    A simple and benign procedure for the synthesis of aryl allyl ethers has been developed using phenols, allyl acetates and magnetically recyclable silica supported palladium catalyst in water; performance of reaction in air and easy separation of the catalyst using an external mag...

  8. Structural Magnetic Resonance Imaging Data Do Not Help Support DSM-5 Autism Spectrum Disorder Category

    ERIC Educational Resources Information Center

    Pina-Camacho, Laura; Villero, Sonia; Boada, Leticia; Fraguas, David; Janssen, Joost; Mayoral, Maria; Llorente, Cloe; Arango, Celso; Parellada, Mara

    2013-01-01

    This systematic review aims to determine whether or not structural magnetic resonance imaging (sMRI) data support the DSM-5 proposal of an autism spectrum disorder (ASD) diagnostic category, and whether or not classical DSM-IV autistic disorder (AD) and Asperger syndrome (AS) categories should be subsumed into it. The most replicated sMRI findings…

  9. Nonlinear instability of wormholes supported by exotic dust and a magnetic field

    SciTech Connect

    Sarbach, Olivier; Zannias, Thomas

    2010-02-15

    Recently, spherically symmetric, static wormholes supported by exotic dust and a radial magnetic field have been derived and argued to be stable with respect to linear radial fluctuations. In this report we point out that these wormholes are unstable due to the formation of shell-crossing singularities when the nonlinearities of the theory are taken into account.

  10. Narratives for Obesity: Effects of Weight Loss and Attribution on Empathy and Policy Support

    ERIC Educational Resources Information Center

    Thibodeau, Paul H.; Uri, Rachel; Thompson, Briana; Flusberg, Stephen J.

    2017-01-01

    Despite an urgent need to address the issue of obesity, little research has examined the psychological factors that influence support for obesity-related policy initiatives, which represent an important tool for addressing this complex health issue. In the present study, we measured the degree to which people supported obesity-related policy…

  11. Types and Nature of Parental Support for Overweight Students to Cope with Weight-Related Teasing

    ERIC Educational Resources Information Center

    Zhao, Qi; Li, Weidong; Rukavina, Paul B.

    2017-01-01

    Background: Parental support can protect adolescents from various forms of bullying. There is a lack of in-depth information about what social support parents provide to overweight adolescents when they are teased at school. In this study, we took an initial step to address this gap in the literature by describing the types and nature of support…

  12. T2*-Weighted and Diffusion Magnetic Resonance Imaging Differentiation of Cerebral Fat Embolism From Diffuse Axonal Injury.

    PubMed

    Rutman, Aaron M; Rapp, Elliot J; Hippe, Daniel S; Vu, Baoanh; Mossa-Basha, Mahmud

    2017-07-13

    This study differentiates cerebral fat embolism (CFE) and diffuse axonal injury (DAI) on diffusion-weighted magnetic resonance imaging (DWI) and T2*-weighted magnetic resonance imaging. Consecutive CFE and DAI cases were retrospectively selected. Hemorrhages were characterized by number, size/shape, and distribution, whereas DWI lesions by pattern. The number of hemorrhages was compared using the Mann-Whitney test with adjustment for multiple comparisons, whereas DWI abnormality was compared using Fisher exact test. Seven CFE and 20 DAI patients were included. Cerebral fat embolism had significantly more hemorrhages than DAI (mean, 670 ± 407 vs 136 ± 87; P = 0.01), particularly in the frontal (P = 0.025), parietal (P = 0.002), and occipital lobes (P = 0.01), the corpus callosum (P = 0.01), and cerebellum (P = 0.01). Cerebral fat embolism microhemorrhages were punctate/round, whereas DAI hemorrhages were small/medium sized (P < 0.001) and linear (P = 0.001). On DWI, DAI typically had few scattered abnormalities, whereas CFE had confluent abnormalities (P < 0.05). Magnetic resonance imaging can differentiate CFE from DAI. Cerebral fat embolism demonstrates more hemorrhages. Larger or linear hemorrhages favor DAI. Diffuse confluent diffusion restriction favors CFE, whereas few scattered foci favor DAI.

  13. Design of set-point weighting PIλ + Dμ controller for vertical magnetic flux controller in Damavand tokamak.

    PubMed

    Rasouli, H; Fatehi, A

    2014-12-01

    In this paper, a simple method is presented for tuning weighted PI(λ) + D(μ) controller parameters based on the pole placement controller of pseudo-second-order fractional systems. One of the advantages of this controller is capability of reducing the disturbance effects and improving response to input, simultaneously. In the following sections, the performance of this controller is evaluated experimentally to control the vertical magnetic flux in Damavand tokamak. For this work, at first a fractional order model is identified using output-error technique in time domain. For various practical experiments, having desired time responses for magnetic flux in Damavand tokamak, is vital. To approach this, at first the desired closed loop reference models are obtained based on generalized characteristic ratio assignment method in fractional order systems. After that, for the identified model, a set-point weighting PI(λ) + D(μ) controller is designed and simulated. Finally, this controller is implemented on digital signal processor control system of the plant to fast/slow control of magnetic flux. The practical results show appropriate performance of this controller.

  14. Weight Status as a Moderator of the Relationship Between Motivation, Emotional Social Support, and Physical Activity in Underserved Adolescents

    PubMed Central

    Wilson, Dawn K.; Lawman, Hannah G.; Van Horn, M. Lee

    2013-01-01

    Objective This study examined weight status as a moderator of the relationship between motivation (controlled, autonomous, regulatory), emotional social support (parents, peers) and moderate-to-vigorous physical activity (MVPA) in underserved adolescents (ethnic minority, low-income). Methods Participants from the Active by Choice Today Trial (n = 1,416; 54% girls, 73% African American, 52% overweight/obese) completed baseline measures, including height and weight, psychosocial surveys, and 7-day accelerometry estimates. Weight status was defined by body mass index z-score (zBMI). Results Weight status moderated the effects of controlled, autonomous, and regulatory motivation on MVPA, such that these variables were more strongly associated with MVPA in adolescents with lower versus higher zBMI scores. Conclusions A better understanding of why motivation is not related to MVPA in underserved youth with a higher weight status is needed. Future pediatric obesity treatment in underserved youth may need to move beyond motivation into environmental factors associated with long-term behavior change. PMID:23378172

  15. Treadmill training with partial body-weight support after anterior cruciate ligament reconstruction: a randomized controlled trial

    PubMed Central

    luo, Yuan; Shen, Weizhong; Jiang, Zhong; Sha, Jiao

    2016-01-01

    [Purpose] To compare the effects of treadmill training with partial body weight support (TTPBWS) and conventional physical therapy (PT) on subjects with anterior cruciate ligament reconstructions. [Subjects and Methods] A total of 40 subjects were randomly allocated to either a treatment group or a control group. Subjects received either treadmill training with partial body weight support (treatment group) or conventional physical therapy (control group). The circumferences of the lower extremities, Holden classifications, 10-meter walking times and the International Knee Documentation Committee (IKDC) scores were compared at 12 and 24 weeks post-operation. The knee joint stability was tested at 24 weeks post-operation using a KT-1000. [Results] Significant differences were found between the two groups at the 12 weeks post-operation. For most of the measures, there was no significant difference between the groups at 24 weeks post-operation. Interestingly, for most of the measures, there was no significant difference between their values in the treatment group at 12 weeks and their values in the control group at 24 weeks post-operation. [Conclusion] The function of a subject’s lower extremities can be improved and the improvement was clearly accelerated by the intervention of treadmill training with partial body weight support, without compromising the stability of the knee joints in a given follow-up period. PMID:28174445

  16. Innovations in the Use of Interactive Technology to Support Weight Management.

    PubMed

    Spruijt-Metz, D; Wen, C K F; O'Reilly, G; Li, M; Lee, S; Emken, B A; Mitra, U; Annavaram, M; Ragusa, G; Narayanan, S

    2015-12-01

    New and emerging mobile technologies are providing unprecedented possibilities for understanding and intervening on obesity-related behaviors in real time. However, the mobile health (mHealth) field has yet to catch up with the fast-paced development of technology. Current mHealth efforts in weight management still tend to focus mainly on short message systems (SMS) interventions, rather than taking advantage of real-time sensing to develop just-in-time adaptive interventions (JITAIs). This paper will give an overview of the current technology landscape for sensing and intervening on three behaviors that are central to weight management: diet, physical activity, and sleep. Then five studies that really dig into the possibilities that these new technologies afford will be showcased. We conclude with a discussion of hurdles that mHealth obesity research has yet to overcome and a future-facing discussion.

  17. Innovations in the Use of Interactive Technology to Support Weight Management

    PubMed Central

    Spruijt-Metz, D.; Wen, C.K.F.; O’Reilly, G.; Li, M.; Lee, S; Emken, B.A.; Mitra, U.; Annavaram, M.; Ragusa, G.; Narayanan, S.

    2015-01-01

    New and emerging mobile technologies are providing unprecedented possibilities for understanding and intervening on obesity-related behaviors in real time. However, the mobile health (mHealth) field has yet to catch up with the fast-paced development of technology. Current mHealth efforts in weight management still tend to focus mainly on short message systems (SMS) interventions, rather than taking advantage of real-time sensing to develop Just-In-Time, Adaptive Interventions (JITAIs). This paper will give an overview of the current technology landscape for sensing and intervening on three behaviors that are central to weight management; diet, physical activity, and sleep. Then five studies that really dig into the possibilities that these new technologies afford will be showcased. We conclude with a discussion of hurdles that mHealth obesity research has yet to overcome, and a future-facing discussion. PMID:26364308

  18. [Susceptibility weighted magnetic resonance sequences "SWAN, SWI and VenoBOLD": technical aspects and clinical applications].

    PubMed

    Hodel, J; Rodallec, M; Gerber, S; Blanc, R; Maraval, A; Caron, S; Tyvaert, L; Zuber, M; Zins, M

    2012-05-01

    Susceptibility-weighted MR sequences, T2 star weighted angiography (SWAN, General Electric), Susceptibility weighted imaging (SWI, Siemens) and venous blood oxygen level dependant (VenoBOLD, Philips) are 3D spoiled gradient-echo sequence that provide a high sensitivity for the detection of blood degradation products, calcifications, and iron deposits. For all these sequences, an appropriate echo time allows for the visualization of susceptibility differences between adjacent tissues. However, each of these sequences presents a specific technical background. The purpose of this review was to describe 1/the technical aspects of SWAN, VenoBOLD and SWI sequences, 2/the differences observed in term of contrast within the images, 3/the key imaging findings in neuroimaging using susceptibility-weighted MR sequences.

  19. Diagnostic Performance of Diffusion-weighted Magnetic Resonance Imaging in Bone Malignancy

    PubMed Central

    Liu, Li-Peng; Cui, Long-Biao; Zhang, Xin-Xin; Cao, Jing; Chang, Ning; Tang, Xing; Qi, Shun; Zhang, Xiao-Liang; Yin, Hong; Zhang, Jian

    2015-01-01

    Abstract Current state-of-the-art nuclear medicine imaging methods (such as PET/CT or bone scintigraphy) may have insufficient sensitivity for predicting bone tumor, and substantial exposure to ionizing radiation is associated with the risk of secondary cancer development. Diffusion-weighted MRI (DW-MRI) is radiation free and requires no intravenous contrast media, and hence is more suitable for population groups that are vulnerable to ionizing radiation and/or impaired renal functions. This meta-analysis was conducted to investigate whether whole-body DW-MRI is a viable means in differentiating bone malignancy. Medline and Embase databases were searched from their inception to May 2015 without language restriction for studies evaluating DW-MRI for detection of bone lesions. Methodological quality was assessed by the quality assessment of diagnostic studies (QUADAS-2) instrument. Sensitivities, specificities, diagnostic odds ratio (DOR), and areas under the curve (AUC) were used as measures of the diagnostic accuracy. We combined the effects by using the random-effects mode. Potential threshold effects and publication bias were investigated. We included data from 32 studies with 1507 patients. The pooled sensitivity, specificity, and AUC were 0.95 (95% CI, 0.90–0.97), 0.92 (95% CI, 0.88–0.95), and 0.98 on a per-patient basis, and they were 0.91 (95% CI, 0.87–0.94), 0.94 (95% CI, 0.90–0.96), and 0.97 on a per-lesion basis. In subgroup analysis, there is no statistical significance found in the sensitivity and specificity of using DWI only and DWI combined with other morphological or functional imaging sequence in both basis (P > 0.05). A b value of 750 to 1000 s/mm2 enables higher AUC and DOR for whole-body imaging purpose when compared with other values in both basis either (P < 0.01). The ROC space did not show a curvilinear trend of points and a threshold effect was not observed. According to the Deek's plots, there was no publication bias on

  20. In Vivo Magnetization Transfer and Diffusion-Weighted Magnetic Resonance Imaging Detects Thrombus Composition in a Mouse Model of Deep Vein Thrombosis

    PubMed Central

    Saha, Prakash; Modarai, Bijan; Smith, Alberto; Botnar, René M.

    2014-01-01

    Background Deep vein thrombosis remains a major health problem necessitating accurate diagnosis. Thrombolysis is associated with significant morbidity and is effective only for the treatment of unorganized thrombus. We tested the feasibility of in vivo magnetization transfer (MT) and diffusion-weighted magnetic resonance imaging to detect thrombus organization in a murine model of deep vein thrombosis. Methods and Results Deep vein thrombosis was induced in the inferior vena cava of male BALB/C mice. Magnetic resonance imaging was performed at days 1, 7, 14, 21, and 28 after thrombus induction using MT, diffusion-weighted, inversion-recovery, and T1-mapping protocols. Delayed enhancement and T1 mapping were repeated 2 hours after injection of a fibrin contrast agent. Finally, excised thrombi were used for histology. We found that MT and diffusion-weighted imaging can detect histological changes associated with thrombus aging. MT rate (MTR) maps and percentage of MT rate (%MTR) allowed visualization and quantification of the thrombus protein content, respectively. The %MTR increased with thrombus organization and was significantly higher at days 14, 21, and 28 after thrombus induction (days 1, 7, 14, 21, 28: %MTR=2483±451, 2079±1210, 7029±2490, 10 295±4356, 32 994±25 449; Panova<0.05). There was a significant positive correlation between the %MTR and the histological protein content of the thrombus (r=0.70; P<0.05). The apparent diffusion coefficient was lower in erythrocyte-rich and collagen-rich thrombus (0.72±0.10 and 0.69±0.05 [×10−3 mm2/s]). Thrombus at days 7 and 14 had the highest apparent diffusion coefficient values (0.95±0.09 and 1.10±0.18 [×10−3 mm2/s]). Conclusions MT and diffusion-weighted magnetic resonance imaging sequences are promising for the staging of thrombus composition and could be useful in guiding medical intervention. PMID:23564561

  1. Structural Design and Analysis for a Double-Band Cold Mass Support of the MICE Coupling Magnet

    SciTech Connect

    Green, Michael A; Wu, Hong; Liu, X. K.; Wang, Li; Li, S. Y.; Guo, XingLong; Pan, Heng; Xu, FengYu

    2009-07-01

    The cooling channel of Muon Ionization Cooling Experiment (MICE) consists of eighteen superconducting solenoid coils, which are magnetically hooked together. A pair ofcoupling magnets operating at 4 K is applied to produce up to .6 T magnetic field on the magnet centerline to keep muon beam within the RF cavity windows. The peak magnetic force on the coupling magnet from other magnets in the MICE channel is up to 500 kN inlongitudinal direction, and the requirements for magnet center and axis azimuthal angle at 4 K are stringent. A self-centered double-band cold mass support system with intermediatethermal interruption is applied for the coupling magnet. The physical center of the magnet does not change as it is cooled down from 300 K to 4.2 K with this support system. In this paper the design parameters of the support system are discussed. The integral analysis of the support system using FEA method was carried out to etermine the tension forces in bands when various loads are applied. The magnet centre displacement and concentricity deviation form the axis of the warm bore are obtained, and the peak tension in support bands is also determined according to the simulation results.

  2. Types and Nature of Parental Support for Overweight Students to Cope With Weight-Related Teasing.

    PubMed

    Zhao, Qi; Li, Weidong; Rukavina, Paul B

    2017-10-01

    Parental support can protect adolescents from various forms of bullying. There is a lack of in-depth information about what social support parents provide to overweight adolescents when they are teased at school. In this study, we took an initial step to address this gap in the literature by describing the types and nature of support that parents provided to their overweight child when they were teased. A conversational style semistructured interview/prompts and probes were conducted with 28 volunteering parents. Inductive content analysis was used to analyze the data. Data trustworthiness was established through a variety of strategies. Six themes emerged from the data: (1) having conversations, being encouraging, and "being supportive"; (2) using religion to teach self-acceptance and comfort their child; (3) offering advice on how to cope with the teasing; (4) fostering their child's self-esteem; (5) teaching reality and acceptance of criticism in early life; and (6) seeking support from other parents or professionals. Parents offered multiple supports for their child when they were teased. This information can facilitate the development of effective family-based interventions on coping with teasing among overweight students. Future research is also needed to examine the effectiveness of the recommended interventions. © 2017, American School Health Association.

  3. Structure and Stability of Filamentary Clouds Supported by Lateral Magnetic Field

    NASA Astrophysics Data System (ADS)

    Hanawa, Tomoyuki; Tomisaka, Kohji

    2015-03-01

    We have constructed two types of analytical models for an isothermal filamentary cloud supported mainly by magnetic tension. The first one describes an isolated cloud while the second considers filamentary clouds spaced periodically. Both models assume that the filamentary clouds are highly flattened. The former is proved to be the asymptotic limit of the latter in which each filamentary cloud is much thinner than the distance to the neighboring filaments. We show that these models reproduce the main features of the 2D equilibrium model of Tomisaka for a filamentary cloud threaded by a perpendicular magnetic field. It is also shown that the critical mass to flux ratio is M/Φ={{(2π \\sqrt{G})}-1}, where M, Φ and G denote the cloud mass, the total magnetic flux of the cloud, and the gravitational constant, respectively. This upper bound coincides with that for an axisymmetric cloud supported by poloidal magnetic fields. We apply the variational principle for studying the Jeans instability of the first model. Our model cloud is unstable against fragmentation as well as the filamentary clouds threaded by a longitudinal magnetic field. The fastest growing mode has a wavelength several times longer than the cloud diameter. The second model describes quasi-static evolution of a filamentary molecular cloud by ambipolar diffusion.

  4. Self-gravitating Magnetically Supported Protostellar Disks and the Formation of Substellar Companions

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Yun

    2002-08-01

    Isolated low-mass stars are formed, in the standard picture, from the collapse of dense cores condensed out of strongly magnetized molecular clouds. The dynamically collapsing inflow traps nearly half of the critical magnetic flux needed for the core support and deposits it in a small region surrounding the protostar. It has been argued previously that the deposited flux can slow down the inflow, allowing matter to pile up and settle along field lines into a magnetically supported, circumstellar disk. Here we show that the disk typically contains ~10% of the stellar mass and that it could become self-gravitating under plausible conditions during the rapidly accreting, ``Class 0'' phase of star formation. Subsequent fragmentation of the self-gravitating, magnetically subcritical disk, driven by magnetic diffusion, could produce fragments of substellar masses, which collapse to form brown dwarfs and possibly massive planets. This scenario predicts substellar object formation at distances of order 100 AU from the central star, although orbital evolution is possible after formation. It may provide an explanation for the small, but growing, number of brown dwarf companions found around nearby stars by direct imaging. The relatively large formation distances make the substellar companions vulnerable to dynamic ejection, particularly in binary (multiple) systems and dense clusters. Those ejected may account for, at least in part, the isolated brown dwarfs and perhaps free-floating planetary mass objects.

  5. Sprint running with a body-weight supporting kite reduces ground contact time in well-trained sprinters.

    PubMed

    Kratky, Sascha; Müller, Erich

    2013-05-01

    It is well founded that ground contact time is the crucial part of sprinting because the available time window to apply force to the ground diminishes with growing running velocity. In view of this knowledge, the purpose of this study was to investigate the effects of body-weight support during full-effort sprints on ground contact time and selected stride parameters in 19 Austrian male elite sprinters. A kite with a lifting effect combined with a towing system to erase drag was used. The subjects performed flying 20-m sprints under 3 conditions: (a) free sprint; (b) body-weight supported sprint-normal speed (BWS-NS); and (c) body-weight supported sprint-overspeed (BWS-OS). Sprint cycle characteristics were recorded during the high-speed phase by an optical acquisition system. Additionally, running velocity was derived from the 20-m sprint time. Compared with the fastest free sprint, running velocity, step length, and step frequency remained unchanged during BWS-NS, whereas ground contact time decreased (-5.80%), and air time increased (+5.79%) (both p < 0.001). Throughout, BWS-OS ground contact time (-7.66%) was reduced, whereas running velocity (+2.72%), air time (+4.92%), step length (+1.98%) (all p < 0.001), and step frequency (+1.05%; p < 0.01) increased. Compared with BWS-NS, BWS-OS caused an increase in running velocity (+3.33%), step length (+1.92%) (both p < 0.001), and step frequency (+1.37%; p < 0.01), whereas ground contact time was diminished (-1.97%; p < 0.001). In summary, sprinting with a body-weight supporting kite appeared to be a highly specific method to simulate an advanced performance level, indicated by higher running velocities requiring reduced ground contact times. The additional application of an overspeed condition led to a further reduction of ground contact time. Therefore, we recommend body-weight supported sprinting as an additional tool in sprint training.

  6. Prediction of Stroke Subtype and Recanalization Using Susceptibility Vessel Sign on Susceptibility-Weighted Magnetic Resonance Imaging.

    PubMed

    Kang, Dong-Wan; Jeong, Han-Gil; Kim, Do Yeon; Yang, Wookjin; Lee, Seung-Hoon

    2017-06-01

    The susceptibility vessel sign (SVS) is a hypointense signal visualized because of the susceptibility effect of thrombi, sensitively detected on susceptibility-weighted magnetic resonance imaging. The relationship of SVS parameters with the stroke subtype and recanalization status after endovascular treatment remains uncertain. The data from 89 patients with acute stroke caused by anterior circulation infarcts who underwent susceptibility-weighted magnetic resonance imaging before endovascular treatment were examined. Independent reviewers, blinded to the stroke subtype and recanalization status, measured the SVS diameter, length, and estimated volume. The intra- and interrater agreements of the SVS parameters were assessed. The SVS was identified in 78% of the patients. SVS was more commonly associated with cardioembolism than with noncardioembolism (P=0.01). The SVS diameter (P<0.01) and length (P=0.01) were larger in the cardioembolism group. The SVS diameter was larger in the recanalization group (thrombolysis in cerebral infarction ≥2b) than in the nonrecanalization group (P=0.04). Multivariable analysis revealed that the SVS diameter was an independent predictor of cardioembolism (adjusted odds ratio, 1.97; 95% confidence interval, 1.34-2.90; P<0.01). There was no significant association between the SVS volume and the recanalization status (adjusted odds ratio, 1.003; 95% confidence interval, 0.999-1.006; P=0.12). The optimal cutoff value of the SVS diameter for the cardioembolism was 5.5 mm (sensitivity, 45.6%; specificity, 93.8%). Increased SVS diameter on susceptibility-weighted magnetic resonance imaging may predict cardioembolism. No clear association was found between SVS volume and endovascular recanalization. © 2017 The Authors.

  7. A comparative quantitative analysis of magnetic susceptibility artifacts in echo planar and PROPELLER diffusion-weighted images

    NASA Astrophysics Data System (ADS)

    Cho, Jae-Hwan; Lee, Hae-Kag; Yang, Han-Joon; Lee, Gui-Won; Park, Yong-Soon; Chung, Woon-Kwan

    2013-01-01

    In this study, the authors investigated whether periodically-rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion-weighted imaging (DWI) can remove magnetic susceptibility artifacts and compared apparent diffusion coefficient (ADC) values for PROPELLER DWI and the common echo planar (EP) DWI. Twenty patients that underwent brain MRI with a metal dental implant were selected. A 3.0T MR scanner was then used to obtain EP DWI, PROPELLER DWI, and corresponding apparent diffusion coefficient (ADC) maps for a b-value of 0 and 1,000 s/mm2. The frequencies of magnetic susceptibility artifacts in four parts of the brain (bilateral temporal lobes, pons, and orbit) were selected. In the ADC maps, we measured the ADC values of both sides of the temporal lobe and the pons. According to the study results, the frequency of magnetic susceptibility artifacts in PROPELLER DW images was lower than it was in EP DW images. In ADC maps, the ADC values of the bilateral temporal lobes and the pons were all higher in PROPELLER ADC maps than in EP ADC maps. Our findings show that when a high-field MRI machine is used, magnetic susceptibility artifacts can distort anatomical structures and produce high-intensity signals. Furthermore, our findings suggest that in many cases, PROPELLER DWI would be helpful in terms of achieving a correct diagnosis.

  8. Parental support for policy measures and school-based efforts to address weight-based victimization of overweight youth.

    PubMed

    Puhl, R M; Luedicke, J

    2014-04-01

    Despite research documenting weight-based victimization (WBV) toward overweight youth in the school setting, little work has examined parental perceptions of this problem or potential policy strategies to help protect youth who are teased and bullied about their weight. This study assessed parental reports of WBV in youth and parental support for potential measures to address this problem, including implementation of school-based resources, policies, and state and federal laws. A national sample of parents in the United States (N=919) completed an online questionnaire about their perceptions of WBV in the school setting, including whether or not their child had experienced or witnessed WBV. Parents were also asked the degree to which they would support potential policy strategies to address WBV in schools, including school-based policies and state and federal laws to address weight-based bullying in youth. Parents perceived overweight youth to be vulnerable to WBV at school, but less than half of parents perceived schools to be prepared to deal with instances of WBV. Parents (both with and without overweight children) agreed that schools should implement anti-bullying policies that include specific protections for students who are overweight or obese, increase resources available to youth who experience WBV at school, and promote awareness about this problem. Over two-thirds of parents agreed that state anti-bullying laws should include specific protections against weight-related bullying. These findings indicate that there is substantial support from parents, both with and without overweight children, to implement a range of policy measures to address this WBV at the school, state, and federal level.

  9. Long-range ordering in the lyotropic lamellar phase studied by high-resolution magnetic resonance diffusion-weighted imaging.

    PubMed

    Szutkowski, Kosma; Jurga, Stefan

    2010-01-14

    Diffusion-weighted magnetic resonance imaging (DW MRI) was applied to the lyotropic lamellar phase of the dodecylammonium chloride/water system (DDACl/H(2)O). In the course of employing a well-known medical imaging method, namely, diffusion tensor imaging (DTI), the system morphology was assessed accurately in the most straightforward way by two-dimensional visualization of eigenvectors associated with planar distribution of effective diffusion tensors throughout the whole slice with 40 microm in-plane resolution. Long-range order was observed in the studied lamellar phase, and morphology was best described by a combination of three- and one-dimensional diffusion.

  10. Long-lived resonances supported by a contact interaction in crossed magnetic and electric fields

    SciTech Connect

    Krajewska, K. Kaminski, J.Z.; Potvliege, R.M.

    2008-11-15

    The lifetime of the resonance states of an electron interacting with a zero-range potential in the presence of crossed magnetic and electric fields is studied for the case where the electron is confined in the direction of the magnetic field by a parabolic quantum well. It is shown that long-lived electric field-induced resonances exist in this system even when the zero-range potential does not support any field-free bound state. The relationship of these resonances with the Landau states localized near the point interaction is discussed.

  11. Evaluation of public health professionals' capacity to implement environmental changes supportive of healthy weight.

    PubMed

    Gantner, Leigh A; Olson, Christine M

    2012-08-01

    Community-based interventions to promote healthy weights by making environmental and policy changes in communities may be an important strategy in reversing the obesity epidemic. However, challenges faced by local public health professionals in facilitating effective environmental and policy change need to be better understood and addressed. To better understand capacity-building needs, this study evaluated the efforts of the Healthy Start Partnership, a university-community project to promote healthy weights in young families in a rural eight-county area of upstate New York. Qualitative interviews (n=30) and pre/post surveys (n=31) were conducted over three years of the intervention. Challenges faced by partners significantly slowed progress of environmental interventions in some communities. First, many partners did not feel their "regular" jobs afforded them sufficient time to do community work. Second, many partners did not feel they had the personal political power to work on broader environmental, policy, or system change issues. Third, facilitating and policy change and reaching out to non-traditional partners, like businesses, required developing a new set of public health skills. Fourth, the long-time frame of environmental and policy work meant that many efforts would exceed the grant period. Building local public health leaders for environmental and policy change necessitates that these challenges are acknowledged and addressed.

  12. Diffusion-weighted magnetic resonance imaging combined with T2-weighted images in the detection of small breast cancer: a single-center multi-observer study.

    PubMed

    Wu, Lian-Ming; Chen, Jie; Hu, Jiani; Gu, Hai-Yan; Xu, Jian-Rong; Hua, Jia

    2014-02-01

    Breast cancer is the most common cancer in women worldwide. However, it remains a difficult diagnosis problem to differentiate between benign and malignant breast lesions, especially in small early breast lesions. To assess the diagnostic value of diffusion-weighted imaging (DWI) combined with T2-weighted imaging (T2WI) for small breast cancer characterization. Fifty-eight patients (65 lesions) with a lesion <2 cm in diameter underwent 3.0 Tesla breast magnetic resonance imaging (MRI) including DWI and histological analysis. Three observers with varying experience levels reviewed MRI. The probability of breast cancer in each lesion on MR images was recorded with a 5-point scale. Areas under the receiver-operating characteristic curve (AUCs) were compared by using the Z test; sensitivity and specificity were determined with the Z test after adjusting for data clustering. AUC of T2WI and DWI (Observer 1, 0.95; Observer 2, 0.91; Observer 3, 0.83) was greater than that of T2WI (Observer 1, 0.80; Observer 2, 0.74; Observer 3, 0.70) for all observers (P < 0.0001 in all comparisons). Sensitivity of T2WI and DWI (Observer 1, 90%; Observer 2, 93%; and Observer 3, 86%) was greater than that of T2WI alone (Observer 1, 76%; Observer 2, 83%; Observer 3, 79%) for all observers (P < 0.0001 in all comparisons). Specificity of T2WI and DWI was greater than that of T2WI alone for observer 1 (89% vs. 72%, P < 0.01) and observer 2 (94% vs. 78%, P < 0.001). DWI combined with T2WI can improve the diagnostic performance of MRI in small breast cancer characterization. It should be considered selectively in the preoperative evaluation of patients with small lesions of the breast.

  13. Detection of the index tumour and tumour volume in prostate cancer using T2-weighted and diffusion-weighted magnetic resonance imaging (MRI) alone.

    PubMed

    Rud, Erik; Klotz, Dagmar; Rennesund, Kristin; Baco, Eduard; Berge, Viktor; Lien, Diep; Svindland, Aud; Lundeby, Eskild; Berg, Rolf E; Eri, Lars M; Eggesbø, Heidi B

    2014-12-01

    To examine the performance of T2-weighted (T2W) and diffusion-weighted (DW) magnetic resonance imaging (MRI) for detecting the index tumour in patients with prostate cancer and to examine the agreement between MRI and histology when assessing tumour volume (TV) and overall tumour burden. The study included 199 consecutive patients with biopsy confirmed prostate cancer randomised to MRI before radical prostatectomy from December 2009 to July 2012. MRI-detected tumours (MRTs) were ranked from 1 to 3 according to decreasing volume and were compared with histologically detected tumours (HTs) ranked from 1 to 3, with HT 1 = index tumour. Whole-mount section histology was used as a reference standard. The TVs of true-positive MRTs (MRTVs 1-3) were compared with the TVs found by histology (HTVs 1-3). All tumours were registered on a 30-sector map and by classifying each sector as positive/negative, the rate of true-positive and -negative sectors was calculated. The detection rate for the HT 1 (index tumour) was 92%; HT 2, 45%; and HT 3, 37%. The MRTV 1-3 vs the HTV 1-3 were 2.8 mL vs 4.0 mL (index tumour, P < 0.001), 1.0 mL vs 0.9 mL (tumour 2, P = 0.413), and 0.6 mL vs 0.5 mL (tumour 3, P = 0.492). The rate of true-positive and -negative sectors was 50% and 88%, κ = 0.39. A combination of T2W and DW MRI detects the index tumour in 92% of cases, although MRI underestimates both TV and tumour burden compared with histology. © 2014 The Authors. BJU International © 2014 BJU International.

  14. Patients' experience of a telephone booster intervention to support weight management in Type 2 diabetes and its acceptability.

    PubMed

    Wu, Lihua; Forbes, Angus; While, Alison

    2010-01-01

    We studied the patient experience of a telephone booster intervention, i.e. weekly reinforcement of the clinic advice regarding lifestyle modification advice to support weight loss. Forty six adults with Type 2 diabetes and a body mass index >28 kg/m(2) were randomised into either intervention (n = 25) or control (n = 21) groups. Semi-structured interviews were conducted with the intervention group participants to explore their views and experiences. The patients were satisfied or very satisfied with the telephone calls and most would recommend the intervention to others in a similar situation. The content of the telephone follow-up met their need for on-going support. The benefits arising from the telephone calls included: being reminded to comply with their regimen; prompting and motivating adherence to diabetes self-care behaviours; improved self-esteem; and feeling 'worthy of interest'. The convenience and low cost of telephone support has much potential in chronic disease management.

  15. Pilot and Feasibility Test of a Mobile Health-Supported Behavioral Counseling Intervention for Weight Management Among Breast Cancer Survivors

    PubMed Central

    Quintiliani, Lisa M; Mann, Devin M; Puputti, Marissa; Quinn, Emily; Bowen, Deborah J

    2016-01-01

    task (MET) minutes per week (2791 to 3336, mean change 545 [SD 1694]). Conclusions Findings support the conduct of a fully powered trial to evaluate the efficacy of mHealth as a feasible intervention modality for breast cancer survivors. Future research should employ accelerometer-based physical activity assessment and consider development of an all-in-one app to integrate devices, messaging, and educational content and other mHealth approaches to support behavioral counselors conducting weight management interventions. PMID:27761518

  16. Pilot and Feasibility Test of a Mobile Health-Supported Behavioral Counseling Intervention for Weight Management Among Breast Cancer Survivors.

    PubMed

    Quintiliani, Lisa M; Mann, Devin M; Puputti, Marissa; Quinn, Emily; Bowen, Deborah J

    2016-01-01

    3336, mean change 545 [SD 1694]). Findings support the conduct of a fully powered trial to evaluate the efficacy of mHealth as a feasible intervention modality for breast cancer survivors. Future research should employ accelerometer-based physical activity assessment and consider development of an all-in-one app to integrate devices, messaging, and educational content and other mHealth approaches to support behavioral counselors conducting weight management interventions.

  17. Pilot and Feasibility Test of a Mobile Health-Supported Behavioral Counseling Intervention for Weight Management Among Breast Cancer Survivors.

    PubMed

    M Quintiliani, Lisa; Mann, Devin M; Puputti, Marissa; Quinn, Emily; Bowen, Deborah J

    2016-05-09

    3336, mean change 545 [SD 1694]). Findings support the conduct of a fully powered trial to evaluate the efficacy of mHealth as a feasible intervention modality for breast cancer survivors. Future research should employ accelerometer-based physical activity assessment and consider development of an all-in-one app to integrate devices, messaging, and educational content and other mHealth approaches to support behavioral counselors conducting weight management interventions. ClinicalTrials.gov NCT02387671; https://clinicaltrials.gov/ct2/show/NCT02387671 (Archived by WebCite at http://www.webcitation.org/6hGEuttbZ).

  18. Effects of improved self-appraisal and mood factors on weight loss in obese women initiating supported exercise.

    PubMed

    Annesi, James J

    2011-01-01

    This study aimed to test to what extent improvements in self-appraisal and mood factors were associated with changes in body mass index (BMI; kg/m2) and waist circumference. Women with obesity (N=171) completed Physical Self-Concept, Exercise Self-Efficacy, Body Areas Satisfaction, Tension, and Depression scales, and were measured on BMI and waist circumference, at baseline and just after a 24-week supported exercise program. With the exception of Physical Self-Concept, improvements on each psychological factor were associated with significantly greater weight and waist circumference improvements. Multiple regression analyses indicated that improvement/non-improvement on the psychological factors explained a significant 9 to 11 percent of the variance in BMI change, and 13 to 20 percent of the variance in waist circumference change. Significant unique contributions to the explained variance in BMI were made by improvements in Exercise Self-Efficacy and Depression, with improvement in Tension also making significant unique contributions to the explained variance in waist circumference change. Consistent with tenets of social cognitive theory, the association of improvements in self-appraisal and mood factors with weight and waist circumference improvements was supported in obese women. Replications and extensions of this preliminary research to, ultimately, improve weight loss theory and treatment, was suggested.

  19. Weighting issues in recreation research and in identifying support for resource conservation management alternatives

    Treesearch

    Amy L. Sheaffer; Jay Beaman; Joseph T. O' Leary; Rebecca L. Williams; Doran M. Mason

    2001-01-01

    Sampling for research in recreation settings in an ongoing challenge. Often certain groups of users are more likely to be sampled. It is important in measuring public support for resource conservation and in understanding use of natural resources for recreation to evaluate issues of bias in survey methodologies. Important methodological issues emerged from a statewide...

  20. One-way helical electromagnetic wave propagation supported by magnetized plasma

    PubMed Central

    Yang, Biao; Lawrence, Mark; Gao, Wenlong; Guo, Qinghua; Zhang, Shuang

    2016-01-01

    In this paper we reveal the presence of photonic one-way helical surface states in a simple natural system- magnetized plasma. The application of an external magnetic field to a bulk plasma body not only breaks time-reversal-symmetry but also leads to separation of Equi-Frequency Contour surfaces (EFCs) to form topologically nontrivial gaps in k space. Interestingly, these EFCs support topologically protected surface states. We numerically investigate an interface between magnetized plasma, using a realistic model for parameter dispersion, and vacuum, to confirm the existence of one-way scatter-immune helical surface states. Unlike previous proposals for achieving photonic one-way propagation, our scheme does not require the use of artificial structures and should therefore be simple to implement experimentally. PMID:26883883

  1. One-way helical electromagnetic wave propagation supported by magnetized plasma

    NASA Astrophysics Data System (ADS)

    Yang, Biao; Lawrence, Mark; Gao, Wenlong; Guo, Qinghua; Zhang, Shuang

    2016-02-01

    In this paper we reveal the presence of photonic one-way helical surface states in a simple natural system- magnetized plasma. The application of an external magnetic field to a bulk plasma body not only breaks time-reversal-symmetry but also leads to separation of Equi-Frequency Contour surfaces (EFCs) to form topologically nontrivial gaps in k space. Interestingly, these EFCs support topologically protected surface states. We numerically investigate an interface between magnetized plasma, using a realistic model for parameter dispersion, and vacuum, to confirm the existence of one-way scatter-immune helical surface states. Unlike previous proposals for achieving photonic one-way propagation, our scheme does not require the use of artificial structures and should therefore be simple to implement experimentally.

  2. Effect of the metal support interactions on the physicochemical and magnetic properties of Ni catalysts

    NASA Astrophysics Data System (ADS)

    Gómez-Polo, C.; Gil, A.; Korili, S. A.; Pérez-Landázabal, J. I.; Recarte, V.; Trujillano, R.; Vicente, M. A.

    2007-09-01

    In this work, the effect of the preparation method on the physicochemical and magnetic properties of nickel-containing catalysts is analysed. The catalysts were prepared by two methods, incipient wetness impregnation and precipitation-deposition using two commercial oxides, γ-Al 2O 3 (Rhône-Poulenc) and SiO 2 (AF125, Kali Chemie) as supports. The precursors were dried at 393 K for 16 h and then calcined at 823 K for 4 h. The physicochemical characterization of the catalysts included nitrogen adsorption, X-ray diffraction (XRD), temperature-programmed reduction (TPR) and chemical analysis. A SQUID magnetometer was employed in the magnetic characterization. The basic compositional and structural characteristics of these Ni-based nanoporous catalysts are analysed in relation to their magnetic response.

  3. How can weight-loss app designers' best engage and support users? A qualitative investigation.

    PubMed

    Tang, Jason; Abraham, Charles; Stamp, Elena; Greaves, Colin

    2015-02-01

    This study explored young adults' experiences of using e-health internet-based computer or mobile phone applications (apps) and what they valued about those apps. A qualitative design was used. Semi-structured interviews were conducted with a community sample of 19 young adults who had used a publicly available phone or internet-based application. Transcripts were analysed using thematic analysis. Participants valued an attractive user interface. Structure, ease of use, personalised features and accessibility (including dual phone-computer access) were all important to participants and users indicated that continued use depended on these design features. Many believed that a focus on calorie counting was too limiting. Some users mentioned behaviour change strategies and known behaviour change techniques utilised by apps including; self-monitoring, goal setting and behavioural feedback. Only a few users reported positive changes in physical activity levels. Use of particular design features and application of evidence-based behaviour change techniques could optimise continued use and the effectiveness of internet/smart phone interventions. Statement of contribution What is already known on this subject? E-health is increasingly used to deliver weight loss/control programs. Most e-health programs have not been founded on evidence-based designs and it is unclear what features and functions users find useful or not so useful. What does this study add? Weight loss app users valued structure, ease of use, personalised features and accessibility. Goal setting and feedback on calorie intake/energy balance were the most widely used behaviour change techniques. Designers should consider an extensive food database, a food scanner, and provision of diaries. © 2014 The British Psychological Society.

  4. Tensor Based Representation and Analysis of Diffusion-Weighted Magnetic Resonance Images

    ERIC Educational Resources Information Center

    Barmpoutis, Angelos

    2009-01-01

    Cartesian tensor bases have been widely used to model spherical functions. In medical imaging, tensors of various orders can approximate the diffusivity function at each voxel of a diffusion-weighted MRI data set. This approximation produces tensor-valued datasets that contain information about the underlying local structure of the scanned tissue.…

  5. 3-D residual eddy current field characterisation: applied to diffusion weighted magnetic resonance imaging.

    PubMed

    O'Brien, Kieran; Daducci, Alessandro; Kickler, Nils; Lazeyras, Francois; Gruetter, Rolf; Feiweier, Thorsten; Krueger, Gunnar

    2013-08-01

    Clinical use of the Stejskal-Tanner diffusion weighted images is hampered by the geometric distortions that result from the large residual 3-D eddy current field induced. In this work, we aimed to predict, using linear response theory, the residual 3-D eddy current field required for geometric distortion correction based on phantom eddy current field measurements. The predicted 3-D eddy current field induced by the diffusion-weighting gradients was able to reduce the root mean square error of the residual eddy current field to ~1 Hz. The model's performance was tested on diffusion weighted images of four normal volunteers, following distortion correction, the quality of the Stejskal-Tanner diffusion-weighted images was found to have comparable quality to image registration based corrections (FSL) at low b-values. Unlike registration techniques the correction was not hindered by low SNR at high b-values, and results in improved image quality relative to FSL. Characterization of the 3-D eddy current field with linear response theory enables the prediction of the 3-D eddy current field required to correct eddy current induced geometric distortions for a wide range of clinical and high b-value protocols.

  6. Tensor Based Representation and Analysis of Diffusion-Weighted Magnetic Resonance Images

    ERIC Educational Resources Information Center

    Barmpoutis, Angelos

    2009-01-01

    Cartesian tensor bases have been widely used to model spherical functions. In medical imaging, tensors of various orders can approximate the diffusivity function at each voxel of a diffusion-weighted MRI data set. This approximation produces tensor-valued datasets that contain information about the underlying local structure of the scanned tissue.…

  7. Hemimicelles/admicelles supported on magnetic graphene sheets for enhanced magnetic solid-phase extraction.

    PubMed

    Liu, Qian; Shi, Jianbo; Wang, Thanh; Guo, Feng; Liu, Lihong; Jiang, Guibin

    2012-09-28

    In this work, superparamagnetic nanoparticle-decorated graphene (MG) sheets were synthesized and used as support for hemimicelles/admicelles for solid-phase extraction (SPE) of different compounds from environmental water samples for the first time. The MG sheets were facilely synthesized by a one-step, one-pot redox reaction between graphene oxide and Fe(II). Due to the large surface area and unique nanosheet morphology, MG served as an excellent nano-scaled support material for hemimicelles and admicelles, exhibiting higher loading capacity than conventional materials and pure Fe₃O₄ nanoparticles. The MG sheets could be negatively or positively charged depending on solution pH, allowing the extraction to be conducted in different modes. In cationic mode, cetyltrimethylammonium bromide (CTAB) was used as micelle-forming reagent, and perfluoroalkyl and polyfluoroalkyl substances (PFASs) and alkylphenols were used as model analytes. In anionic mode, sodium dodecyl sulfate (SDS) was used as micelle-forming reagent and alkyltrimethylammonium salts were selected as analytes. In both modes, the formation processes of hemimicelles/admicelles on MG sheets were studied and the extraction conditions were optimized. For PFASs, the analytical sensitivity was enhanced by 50-113-fold by the extraction, and the method detection limits (MDLs) ranged from 0.15 to 0.50 ng/L. For alkyltrimethylammonium salts, the MDLs were in the range of 1.4-8.0 ng/L. In both modes, good recoveries (56.3-93.9%) and reproducibility (run-to-run RSDs<9.3%) were obtained. The results from this work show a potential new role of graphene in analytical sample preparation.

  8. Effects of different cooling treatments on water diffusion, microcirculation, and water content within exercised muscles: evaluation by magnetic resonance T2-weighted and diffusion-weighted imaging.

    PubMed

    Yanagisawa, Osamu; Takahashi, Hideyuki; Fukubayashi, Toru

    2010-09-01

    In this study, we determined the effects of different cooling treatments on exercised muscles. Seven adults underwent four post-exercise treatments (20-min ice-bag application, 60-min gel-pack application at 10 degrees C and 17 degrees C, and non-cooling treatment) with at least 1 week between treatments. Magnetic resonance diffusion- and T2-weighted images were obtained to calculate the apparent diffusion coefficients (apparent diffusion coefficient 1, which reflects intramuscular water diffusion and microcirculation, and apparent diffusion coefficient 2, which is approximately equal to the true diffusion coefficient that excludes as much of the effect of intramuscular microcirculation as possible) and the T2 values (intramuscular water content level) of the ankle dorsiflexors, respectively, before and after ankle dorsiflexion exercise and after post-exercise treatment. The T2 values increased significantly after exercise and returned to pre-exercise values after each treatment; no significant differences were observed among the four post-exercise treatments. Both apparent diffusion coefficients also increased significantly after exercise and decreased significantly after the three cooling treatments; no significant difference was detected among the three cooling treatments. Local cooling suppresses both water diffusion and microcirculation within exercised muscles. Moreover, although the treatment time was longer, adequate cooling effects could be achieved using the gel-pack applications at relatively mild cooling temperatures.

  9. Diffusion-weighted Magnetic Resonance Imaging as a Novel Imaging Modality in Assessing Treatment Response in Necrotizing Otitis Externa.

    PubMed

    Cherko, Matthew; Nash, Robert; Singh, Arvind; Lingam, Ravi Kumar

    2016-07-01

    To report our initial experience of diffusion-weighted magnetic resonance imaging (DW-MRI) as a novel imaging tool for assessing and monitoring treatment response in necrotizing otitis externa (NOE). Seven adults with a diagnosis of NOE on both clinical and computed tomography (CT) criteria who were subsequently monitored with at least two echoplanar DW-MRI investigations were included in this retrospective longitudinal observational study. Patients underwent magnetic resonance imaging (MRI), including echoplanar diffusion-weighted sequences, within 2 weeks of diagnosis of NOE to determine the extent of infection and to provide a baseline scan for monitoring response to treatment. Repeated imaging was undertaken after the agreed initial course of antimicrobial therapy was completed. The primary outcome measure for complete treatment response was complete resolution of high inflammatory signal on the DW-MRI apparent diffusion coefficient (ADC) map. This was correlated to clinical, biochemical, and other MRI measures of disease resolution. Baseline DW-MRI was carried out in all but one patient within 2 weeks of the initial diagnostic CT scan. Patients had between one and three further DW-MRI scans, at a mean interval of 4.4 months from the initial scan (range, 2-8 months). The decision to terminate or continue therapy correlated with ADC signal findings on DW-MRI in all cases. In comparison, conventional MRI sequences performed less well, as there was some degree of persistent residual soft tissue changes in all cases.

  10. Does Brief Telephone Support Improve Engagement With a Web-Based Weight Management Intervention? Randomized Controlled Trial

    PubMed Central

    Morrison, Leanne; Lloyd, Scott; Phillips, Dawn; Stuart, Beth; Williams, Sarah; Bradbury, Katherine; Roderick, Paul; Murray, Elizabeth; Michie, Susan; Little, Paul; Yardley, Lucy

    2014-01-01

    Background Recent reviews suggest Web-based interventions are promising approaches for weight management but they identify difficulties with suboptimal usage. The literature suggests that offering some degree of human support to website users may boost usage and outcomes. Objective We disseminated the POWeR (“Positive Online Weight Reduction”) Web-based weight management intervention in a community setting. POWeR consisted of weekly online sessions that emphasized self-monitoring, goal-setting, and cognitive/behavioral strategies. Our primary outcome was intervention usage and we investigated whether this was enhanced by the addition of brief telephone coaching. We also explored group differences in short-term self-reported weight loss. Methods Participants were recruited using a range of methods including targeted mailouts, advertisements in the local press, notices on organizational websites, and social media. A total of 786 adults were randomized at an individual level through an online procedure to (1) POWeR only (n=264), (2) POWeR plus coaching (n=247), or (3) a waiting list control group (n=275). Those in the POWeR plus coaching arm were contacted at approximately 7 and 28 days after randomization for short coaching telephone calls aimed at promoting continued usage of the website. Website usage was tracked automatically. Weight was assessed by online self-report. Results Of the 511 participants allocated to the two intervention groups, the median number of POWeR sessions completed was just one (IQR 0-2 for POWeR only, IQR 0-3 for POWeR plus coach). Nonetheless, a substantial minority completed at least the core three sessions of POWeR: 47 participants (17.8%, 47/264) in the POWeR-only arm and 64 participants (25.9%, 64/247) in the POWeR plus coaching arm. Participants in the POWeR plus coaching group persisted with the intervention for longer and were 1.61 times more likely to complete the core three sessions than the POWeR-only group (χ2 1=4.93; OR 1

  11. Isolation of genomic DNA using magnetic nanoparticles as a solid-phase support

    NASA Astrophysics Data System (ADS)

    Saiyed, Z. M.; Ramchand, C. N.; Telang, S. D.

    2008-05-01

    In recent years, techniques employing magnetizable solid-phase supports (MSPS) have found application in numerous biological fields. This magnetic separation procedure offers several advantages in terms of subjecting the analyte to very little mechanical stress compared to other methods. Secondly, these methods are non-laborious, cheap, and often highly scalable. The current paper details a genomic DNA isolation method optimized in our laboratory using magnetic nanoparticles as a solid-phase support. The quality and yields of the isolated DNA from all the samples using magnetic nanoparticles were higher or equivalent to the traditional DNA extraction procedures. Additionally, the magnetic method takes less than 15 min to extract polymerase chain reaction (PCR) ready genomic DNA as against several hours taken by traditional phenol-chloroform extraction protocols. Moreover, the isolated DNA was found to be compatible in PCR amplification and restriction endonuclease digestion. The developed procedure is quick, inexpensive, robust, and it does not require the use of organic solvents or sophisticated instruments, which makes it more amenable to automation and miniaturization.

  12. Fundamental investigations of supported monometallic and bimetallic catalysts by proton magnetic resonance spectroscopy

    SciTech Connect

    Wu, Xi.

    1990-09-21

    Proton magnetic resonance spectroscopy, or nuclear magnetic resonance (NMR) of hydrogen, has been applied to investigate silica-supported Group VIII monometallic and Group VIII-Group IB bimetallic catalysts and alumina- and silica-supported platinum-rhenium bimetallic catalysts. Two adsorbed states of hydrogen, i.e., irreversible and reversible hydrogen, on the surfaces of monometallic Ru, Pt, and Cu particles and bimetallic Ru-Group Ib, Pt-Group Ib, and Pt-Re particles were observed directly via proton NMR. The same amounts of the irreversible hydrogen adsorbed on pure Ru catalysts were measured by both proton NMR and the volumetric technique. The electronic environments on surfaces of monometallic catalysts are sensitive to changes in metal dispersion, state of adsorbed hydrogen, and residual chlorine. Surface compositions for the Ru--Cu and Pt--Cu bimetallic catalysts were determined by NMR of adsorbed hydrogen. 297 refs., 96 figs., 19 tabs.

  13. Managing Knee Osteoarthritis: The Effects of Body Weight Supported Physical Activity on Joint Pain, Function, and Thigh Muscle Strength.

    PubMed

    Peeler, Jason; Christian, Mathew; Cooper, Juliette; Leiter, Jeffrey; MacDonald, Peter

    2015-11-01

    To determine the effect of a 12-week lower body positive pressure (LBPP)-supported low-load treadmill walking program on knee joint pain, function, and thigh muscle strength in overweight patients with knee osteoarthritis (OA). Prospective, observational, repeated measures investigation. Community-based, multidisciplinary sports medicine clinic. Thirty-one patients aged between 55 and 75 years, with a body mass index ≥25 kg/m and mild-to-moderate knee OA. Twelve-week LBPP-supported low-load treadmill walking regimen. Acute knee joint pain (visual analog scale) during full weight bearing treadmill walking, chronic knee pain, and joint function [Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire] during normal activities of daily living, and thigh muscle strength (isokinetic testing). Appropriate methods of statistical analysis were used to compare data from baseline and follow-up evaluation. Participants reported significant improvements in knee joint pain and function and demonstrated significant increases in thigh muscle strength about the degenerative knee. Participants also experienced significant reductions in acute knee pain during full weight bearing treadmill walking and required dramatically less LBPP support to walk pain free on the treadmill. Data suggest that an LBPP-supported low-load exercise regimen can be used to significantly diminish knee pain, enhance joint function, and increase thigh muscle strength, while safely promoting pain-free walking exercise in overweight patients with knee OA. These findings have important implications for the development of nonoperative treatment strategies that can be used in the management of joint symptoms associated with progressive knee OA in at-risk patient populations. This research suggests that LBPP-supported low-load walking is a safe user-friendly mode of exercise that can be successfully used in the management of day-to-day joint symptoms associated with knee OA, helping to improve the

  14. Electronic and magnetic properties of silicon supported organometallic molecular wires: a density functional theory (DFT) study.

    PubMed

    Liu, Xia; Tan, Yingzi; Li, Xiuling; Wu, Xiaojun; Pei, Yong

    2015-08-28

    The electronic and magnetic properties of transition metal (TM = Sc, Ti, V, Cr and Mn) atom incorporated single and double one-dimensional (1D) styrene molecular wires confined on the hydrogen-terminated Si(100) surface are explored for the first time by means of spin-polarized density functional theory, denoted as Si-[TM(styrene)]. It is unveiled that TM atoms bind asymmetrically to the adjacent phenyl rings, which leads to novel electronic and magnetic properties in stark contrast to the well-studied gas phase TM-benzene molecular wires. Si-[Mn(styrene)]∞ and Si-[Cr(styrene)]∞ single molecular wires (SMWs) are a ferromagnetic semiconductor and half metal, respectively. Creation of H-atom defects on the silicon surface can introduce an impurity metallic band, which leads to novel half-metallic magnetism of a Si-[Mn(styrene)]∞ system. Moreover, double molecular wires (DMWs) containing two identical or hetero SMWs are theoretically designed. The [Mn(styrene)]∞-[Cr(styrene)]∞ DMW exhibits half-metallic magnetism where the spin-up and spin-down channels are contributed by two single molecular wires. Finally, we demonstrate that introducing a TM-defect may significantly affect the electronic structure and magnetic properties of molecular wires. These studies provide new insights into the structure and properties of surface supported 1-D sandwiched molecular wires and may inspire the future experimental synthesis of substrate confined organometallic sandwiched molecular wires.

  15. Over ground walking and body weight supported walking improve mobility equally in cerebral palsy: a randomised controlled trial.

    PubMed

    Swe, Ni Ni; Sendhilnnathan, Sunitha; van Den Berg, Maayken; Barr, Christopher

    2015-11-01

    To assess partial body weight supported treadmill training versus over ground training for walking ability in children with mild to moderate cerebral palsy. Randomised controlled trial. A Special Needs school in Singapore. Thirty children with cerebral palsy, aged 6-18, with a Gross Motor Function Classification System score of II-III. Two times 30 minute sessions of walking training per week for 8 weeks, progressed as tolerated, either over ground (control) or using partial body weight supported treadmill training (intervention). The 10 metre walk test, and the 6 minute walk test. Secondary measures were sub-sections D and E on the Gross Motor Function Measure. Outcomes were assessed at baseline, and after 4 and 8 weeks of training. There was no effect of group allocation on any outcome measure, while time was a significant factor for all outcomes. Walking speed improved significantly more in the intervention group by week 4 (0.109 (0.067)m/s vs 0.048 (0.071)m/s, P=0.024) however by week 8 the change from baseline was similar (intervention 0.0160 (0.069)m/s vs control 0.173 (0.109)m/s, P=0.697). All gains made by week 4 were significantly improved on by week 8 for the 10 metre walk test, 6 minute walk test, and the gross motor function measure. Partial body weight supported treadmill training is no more effective than over ground walking at improving aspects of walking and function in children with mild to moderate cerebral palsy. Gains seen in 4 weeks can be furthered by 8 weeks. © The Author(s) 2015.

  16. Design summary of the magnet support structures for the proton storage ring injection line upgrade

    SciTech Connect

    Bernardin, J.D.; Ledford, J.E.; Smith, B.G.

    1997-05-01

    This report summarizes the technical engineering and design issues associated with the Proton Storage Ring (PSR) Injection Line upgrade of the Los Alamos Neutron Science Center (LANSCE). The main focus is on the engineering design calculations of several magnet support structures. The general procedure based upon a set number of design criteria is outlined, followed by a case-by-case summary of the engineering design analyses, reutilization or fabrication callouts and design safety factors.

  17. Thermal support for the very-low-birth-weight infant: role of supplemental conductive heat.

    PubMed

    Topper, W H; Stewart, T P

    1984-11-01

    Heated water pads were placed underneath very-low-birth-weight preterm infants receiving care under overhead radiant warmers with plastic heat shields to evaluate the effects on their thermal environments. The electrical input (watts) to the overhead warmer was monitored and temperatures at various locations in the environment and on the infants were recorded. The electrical input to the radiant warmers decreased significantly (P = 0.0015) with the introduction of the heated water pads. Several of the temperatures recorded during the study also showed significant changes, including increased abdominal skin temperatures in these prone infants (P = 0.007) and decreased back-to-abdomen skin temperature gradients (P = 0.007). Less marked changes included higher mattress or pad temperatures (P = 0.019), lower ambient air temperatures within the plastic heat shields (P = 0.022), and increased infant foot temperatures (P = 0.036). We believe that conduction has a significant influence on the thermal environment of the VLBW infant cared for under an overhead radiant warmer and that the use of a heated water pad can markedly alter heat transfer. The impact of conduction appears to have been previously underestimated.

  18. Effectiveness of web-based self-disclosure peer-to-peer support for weight loss: randomized controlled trial.

    PubMed

    Imanaka, Mie; Ando, Masahiko; Kitamura, Tetsuhisa; Kawamura, Takashi

    2013-07-09

    Obesity is one of the most common public health problems in the industrialized world as a cause of noncommunicable diseases. Although primarily used for one-on-one communication, email is available for uninterrupted support for weight loss, but little is known about the effects of dietitian group counseling for weight control via the Internet. We developed a Web-based self-disclosure health support (WSHS) system for weight loss. This study aims to compare the effect of weight change between those using the WSHS and those using the email health support (EHS). This study was designed as an open prospective individual randomized controlled trial. Eligible participants were aged 35 to 65 years with a body mass index (BMI) of ≥25.0 in their latest health examination. Participants were randomly assigned to either the WSHS group or the EHS group. Thirteen registered dietitians under the direction of a principal dietitian each instructed 6 to 8 participants from the respective groups. All participants in the WSHS group could receive nutritional advice and calculate their nutritive intake from a photograph of a meal on their computer screen from the Internet sent to them by their dietitian, receive supervision from the registered dietitian, and view fellow participants' weight changes and lifestyle modifications. In the EHS group, a participant could receive one-on-one nutritional advice and calculate his/her nutritive intake from the photograph of a meal on computer screen sent by email from his/her dietitian, without being able to view fellow participants' status. The follow-up period was 12 weeks for both groups. The primary outcome measure was change in body weight. The secondary outcome measure included changes in BMI and waist circumference. The intergroup comparison of the changes before and after intervention was evaluated using analysis of covariance. A total of 193 participants were randomly assigned to either the WSHS group (n=97) or the EHS group (n=96). Ten

  19. Effectiveness of Web-Based Self-Disclosure Peer-to-Peer Support for Weight Loss: Randomized Controlled Trial

    PubMed Central

    Imanaka, Mie; Kitamura, Tetsuhisa; Kawamura, Takashi

    2013-01-01

    Background Obesity is one of the most common public health problems in the industrialized world as a cause of noncommunicable diseases. Although primarily used for one-on-one communication, email is available for uninterrupted support for weight loss, but little is known about the effects of dietitian group counseling for weight control via the Internet. Objective We developed a Web-based self-disclosure health support (WSHS) system for weight loss. This study aims to compare the effect of weight change between those using the WSHS and those using the email health support (EHS). Methods This study was designed as an open prospective individual randomized controlled trial. Eligible participants were aged 35 to 65 years with a body mass index (BMI) of ≥25.0 in their latest health examination. Participants were randomly assigned to either the WSHS group or the EHS group. Thirteen registered dietitians under the direction of a principal dietitian each instructed 6 to 8 participants from the respective groups. All participants in the WSHS group could receive nutritional advice and calculate their nutritive intake from a photograph of a meal on their computer screen from the Internet sent to them by their dietitian, receive supervision from the registered dietitian, and view fellow participants’ weight changes and lifestyle modifications. In the EHS group, a participant could receive one-on-one nutritional advice and calculate his/her nutritive intake from the photograph of a meal on computer screen sent by email from his/her dietitian, without being able to view fellow participants’ status. The follow-up period was 12 weeks for both groups. The primary outcome measure was change in body weight. The secondary outcome measure included changes in BMI and waist circumference. The intergroup comparison of the changes before and after intervention was evaluated using analysis of covariance. Results A total of 193 participants were randomly assigned to either the WSHS

  20. Study on the support technology of the light-weighted mirror

    NASA Astrophysics Data System (ADS)

    Zhu, Nengbing; QI, Bo; Ren, Ge; Zhu, Fuyin; Ai, Zhiwei

    2016-10-01

    To reduce the surface deformation of a space remote sensor mirror in space environments, a flexible supporting structure of space mirror is designed to improve the surface accuracy of mirror under operating conditions, making the mirror in good thermal dimensional stability and the structure stiffness meet the requirements of mechanics at the same time. Using the finite element method to do simulation analysis about the surface accuracy and structural strength and dynamic stiffness of the mirror assembly under the force-heat coupling state. Simulation results show that the first-order natural frequency of the mirror component is 393.73Hz, and the RMS values of 1g gravity respectively reach 8.920nm, 1.856nm, 4.516nm; under 1g gravity and 4 degrees centigrade rising coupling state in three directions, the RMS values respectively reach 10.02nm, 3.312nm, 5.718nm, the results meet the design specifications requirement that the RMS value less than λ/50 (λ=632.8nm). Finally, the analysis of the random vibration was carried out on the mirror components, results show that the mirror and its supporting structure was designed reasonable which can meet the requirements of space applications.

  1. [Conventional and diffusion-weighted magnetic resonance imaging and proton spectroscopy in MELAS].

    PubMed

    Casimiro, Carlos; Martins, Joana; Nunes, César; Parreira, Tiago; Batista, Sónia; Cordeiro, Miguel; Matias, Fernando; Rebelo, Olinda; Freitas, Pedro

    2012-01-01

    MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) is a mitochondrial hereditary dysfunction in which the physiopathological mechanism of cerebral lesions is not totally understood as yet. Typically, these lesions are described as having normal to increased apparent diffusion coefficient (ADC), and this has been used to distinguish stroke-like lesions from ischemic lesions. Notwithstanding this, within the last few years, there have been reports of diffusion restriction in stroke-like episodes. Analysis of the diffusion characteristics on serial magnetic resonance imaging (MRI) over a 16 month period, on a patient with MELAS and stroke-like lesions, to investigate the controversial changes of the ADC, reported in the last years. Evaluation of the proton spectroscopy changes in stroke-like lesions and apparently spared brain. We performed four serial magnetic resonance imaging (MRI), including two stroke-like episodes, in a 28-year-old man with MELAS (mitochondrial DNA mutation A3243G). Qualitative analysis of the magnetic resonance images, including the single voxel spectroscopy and ADC maps, with analysis of evolution patterns of the last ones. Both MRI that were performed during those episodes of stroke-like lesion revealed areas of diffusion restriction, coexisting areas of high ADC. During the chronic phase, there was a regression of those changes. Proton spectroscopy showed the presence of lactate and reduction of N-acetyl aspartate peak in stroke-like lesion and the presence of lactate in apparently spared brain. All alterations that were recorded strengthen the view that cytotoxic oedema can occur in stroke-like lesions. Thus, their presence should not weaken the possibility of MELAS, especially if those lesions affect the temporal, parietal and/or occipital lobes, or if they predominantly involve the cortical gray matter, spanning vascular borders and if proton spectroscopy reveals lactate peak in the apparently spared brain.

  2. √Structure and Stability of Filamentary Clouds Supported by Lateral Magnetic Field

    NASA Astrophysics Data System (ADS)

    Hanawa, Tomoyuki; Tomisaka, Kohji

    2015-08-01

    We have constructed two types of analytical models for an isothermal filamentary cloud supported mainly by magnetic tension. The first one describes an isolated cloud while the second considers filamentary clouds spaced periodically. Both the models assume that the filamentary clouds are highly flattened. The former is proved to be the asymptotic limit of the latter in which each filamentary cloud is much thinner than the distance to the neighboring filaments. We show that these models reproduce the main features of the 2D equilibrium model of a filamentary cloud threaded by a perpendicular magnetic field. It is also shown that the critical mass to flux ratio is M/Φ = 1/(2 π√G ) , where M, Φ, and G denote the cloud mass, the total magnetic flux of the cloud, and the gravitational constant, respectively. This upper bound coincides with that for an axisymmetric cloud supported by poloidal magnetic fields. We apply the variational principle for studying the Jeans instability of the first model. Our model cloud is unstable against fragmentation as well as the filamentary clouds threaded by a longitudinal magnetic field. The fastest growing mode has a wavelength several times longer than the cloud diameter. This is because the first model is supercritical. The second model describes quasi-static evolution of a filamentary molecular cloud by ambipolar diffusion. The mass to flux ratio increases at the filament center and exceeds the critical value at a certain point. It is suggested that the filamentary cloud becomes unstable against fragmentation at the critical mass to flux ratio.

  3. Advantages of T2 Weighted Three Dimensional and T1 Weighted Three Dimensional Contrast Medium Enhanced Magnetic Resonance Urography in Examination of the Child Population

    PubMed Central

    Sehic, Adnan; Julardzija, Fuad; Vegar-Zubovic, Sandra; Sefic-Pasic, Irmina

    2017-01-01

    Aim: The aim of this study is to prove the advantages of combined use of T2 weighted three dimensional (T2 W 3D) and T1 weighted three dimensional contrast medium enhanced (T1 W 3D CE) magnetic resonance (MR) urography in displaying urinary tract in child population. Material and methods: Total of 120 patients were included in the study, 71 (59%) male patients and 49 (41%) female patients. The study was conducted on the Radiology clinic, University of Sarajevo Clinical Center, during the period from February to November 2016. Patients were examined on the 1.5T and 3T MRI, with standard protocol which includes T2 W 3D and T1 W 3D contrast medium enhanced MR urography. In the post procesing quantitative measurement of signal intensity and evaluation of the display quality in the area of renal pelvis, middle of ureter and the mouth of the ureter were done. Measurement was concluded on Syngo software B13. Results: Analyzing the acquired data and statistically processing them we got results which have shown higher signal intensity of measured structures on T1 W 3D contrast medium enhanced MR urography on the level p<0.01 and p<0.05 compared to T2 W 3D MR urography in patients that had normal dynamics of contrast medium secretion. However, in kidneys with decreased function, T2 W 3D MR urography provided higher signal intensity and better display compared to T1 W 3D contrast medium enhanced MR urography on the level p<0.05 and p<0.01. Conclusion: T2 W3D MR urography is useful in imaging nonfunctional kidney as well as in patients prone to allergic reactions, where as T1 W3D CE MR urography is at an advantage over T2 W 3D MR urography in imaging the kidney functionality, kidney dynamics measurement, it provides higher MRI signal intensity required for clear 3D reconstructions. PMID:28484293

  4. Gd(III)-Dithiolane Gold Nanoparticles for T1-Weighted Magnetic Resonance Imaging of the Pancreas

    PubMed Central

    Holbrook, Robert J.; Rammohan, Nikhil; Rotz, Matthew W.; MacRenaris, Keith W.; Preslar, Adam T.; Meade, Thomas J.

    2016-01-01

    Pancreatic adenocarcinoma has a 5 year survival of approximately 3% and median survival of 6 months and is among the most dismal of prognoses in all of medicine. This poor prognosis is largely due to delayed diagnosis where patients remain asymptomatic until advanced disease is present. Therefore, techniques to allow early detection of pancreatic adenocarcinoma are desperately needed. Imaging of pancreatic tissue is notoriously difficult, and the development of new imaging techniques would impact our understanding of organ physiology and pathology with applications in disease diagnosis, staging, and longitudinal response to therapy in vivo. Magnetic resonance imaging (MRI) provides numerous advantages for these types of investigations; however, it is unable to delineate the pancreas due to low inherent contrast within this tissue type. To overcome this limitation, we have prepared a new Gd(III) contrast agent that accumulates in the pancreas and provides significant contrast enhancement by MR imaging. We describe the synthesis and characterization of a new dithiolane-Gd(III) complex and a straightforward and scalable approach for conjugation to a gold nanoparticle. We present data that show the nanoconjugates exhibit very high per particle values of r1 relaxivity at both low and high magnetic field strengths due to the high Gd(III) payload. We provide evidence of pancreatic tissue labeling that includes MR images, post-mortem biodistribution analysis, and pancreatic tissue evaluation of particle localization. Significant contrast enhancement was observed allowing clear identification of the pancreas with contrast-to-noise ratios exceeding 35:1. PMID:27050622

  5. Identification of Calcification with Magnetic Resonance Imaging Using Susceptibility-Weighted Imaging: A Case Study

    PubMed Central

    Wu, Zhen; Mittal, Sandeep; Kish, Karl; Yu, Yingjian; Hu, J.; Haacke, E. Mark

    2008-01-01

    Susceptibility weighted imaging (SWI) is a new MRI technique that can identify calcification by using phase images. We present a single case with a partially calcified oligodendroglioma, multiple calcified cysticercosis lesions, and multiple physiologic calcifications in the same patient. SWI phase images and computed tomography (CT) images are compared. SWI phase images showed the same calcified lesions as shown on CT and sometimes some new calcifications. Our conclusion is that SWI filtered phase images can identify calcifications as well as CT in this case. PMID:19097156

  6. Studies of Ciliated Microorganism Swimming with and against a Magnetic Field Tuned Apparent Weight Force

    NASA Astrophysics Data System (ADS)

    Jung, Ilyong; Mickalide, Harry; Valles, James M., Jr.

    2012-11-01

    There is a class of microorganisms that are small enough to swim at low Reynolds number but large enough for gravity to influence their behavior. Remarkably, Paramecia exert a stronger (weaker) propulsion force when swimming against (with) their apparent weight force, W -->. To investigate the source of the swimming speed response, we are examining how the trajectories of single swimmers change when they reverse their direction relative to W -->. We characterize their helical trajectories with three parameters that we can relate to their beating of their cilia using a simple model. The latest results will be described.

  7. SU-E-J-157: Improving the Quality of T2-Weighted 4D Magnetic Resonance Imaging for Clinical Evaluation

    SciTech Connect

    Du, D; Mutic, S; Hu, Y; Caruthers, S; Glide-Hurst, C; Low, D

    2014-06-01

    Purpose: To develop an imaging technique that enables us to acquire T2- weighted 4D Magnetic Resonance Imaging (4DMRI) with sufficient spatial coverage, temporal resolution and spatial resolution for clinical evaluation. Methods: T2-weighed 4DMRI images were acquired from a healthy volunteer using a respiratory amplitude triggered T2-weighted Turbo Spin Echo sequence. 10 respiratory states were used to equally sample the respiratory range based on amplitude (0%, 20%i, 40%i, 60%i, 80%i, 100%, 80%e, 60%e, 40%e and 20%e). To avoid frequent scanning halts, a methodology was devised that split 10 respiratory states into two packages in an interleaved manner and packages were acquired separately. Sixty 3mm sagittal slices at 1.5mm in-plane spatial resolution were acquired to offer good spatial coverage and reasonable spatial resolution. The in-plane field of view was 375mm × 260mm with nominal scan time of 3 minutes 42 seconds. Acquired 2D images at the same respiratory state were combined to form the 3D image set corresponding to that respiratory state and reconstructed in the coronal view to evaluate whether all slices were at the same respiratory state. 3D image sets of 10 respiratory states represented a complete 4D MRI image set. Results: T2-weighted 4DMRI image were acquired in 10 minutes which was within clinical acceptable range. Qualitatively, the acquired MRI images had good image quality for delineation purposes. There were no abrupt position changes in reconstructed coronal images which confirmed that all sagittal slices were in the same respiratory state. Conclusion: We demonstrated it was feasible to acquire T2-weighted 4DMRI image set within a practical amount of time (10 minutes) that had good temporal resolution (10 respiratory states), spatial resolution (1.5mm × 1.5mm × 3.0mm) and spatial coverage (60 slices) for future clinical evaluation.

  8. The relationship between body mass index and unhealthy weight control behaviors among adolescents: the role of family and peer social support.

    PubMed

    Vander Wal, Jillon S

    2012-12-01

    Adolescents classified as overweight or obese are more likely to use unhealthy weight control behaviors such as skipping meals or fasting than their healthy weight peers. Adolescents with low perceived social support may be at particular risk. Therefore, the purpose of the present study was to investigate the association between adolescent overweight and obesity, indices of perceived peer and family social support, and their interaction in the use of unhealthy weight control behaviors among adolescents. The present study used data from the 2001-2002 Health Behavior in School-Aged Children collaborative survey. Participants included 4598 adolescent girls and boys in the ninth and tenth grades. Results of binary logistic regression analyses showed that obese boys and girls were more likely to use unhealthy weight control behaviors than their healthy weight peers. Boys and girls who endorsed difficult communication with their parents, low levels of parent school support, or frequent bullying were more likely to engage in unhealthy weight control behaviors than relevant comparison groups. Among girls, poor classmate relationships were associated with increased use of unhealthy weight control behaviors whereas fewer friendships were associated with decreased use. Results suggest that adolescents are at high risk for use of unhealthy weight control behaviors and would benefit from interventions to increase knowledge and social support for achieving and maintaining a healthy weight.

  9. Could capsaicinoids help to support weight management? A systematic review and meta-analysis of energy intake data.

    PubMed

    Whiting, S; Derbyshire, E J; Tiwari, B

    2014-02-01

    Capsaicinoids are a group of chemicals naturally occurring in chilli peppers with bioactive properties that may help to support weight management. The aim of the present study was to conduct a meta-analysis investigating the potential effects of capsaicinoids on energy intake, to clarify previous observations and form evidence-based conclusions about possible weight management roles. Medical databases (Medline, Web of Knowledge and Scopus) were systematically searched for papers. Search terms were: 'capsaicin(*)' or 'red pepper' or 'chilli(*)' or 'chili(*)' with 'satiety' or 'energy intake'. Of the seventy-four clinical trials identified, 10 were included, 8 of which provided results suitable to be combined in analysis (191 participants). From the studies, 19 effect sizes were extracted and analysed using MIX meta-analysis software. Data analysis showed that capsaicinoid ingestion prior to a meal reduced ad libitum energy intake by 309.9kJ (74.0kcal) p<0.001 during the meal. Results, however, should be viewed with some caution as heterogeneity was high (I(2)=75.7%). Study findings suggest a minimum dose of 2mg of capsaicinoids is needed to contribute to reductions in ad libitum energy intake, which appears to be attributed to an altered preference for carbohydrate-rich foods over foods with a higher fat content. Meta-anlysis findings suggest that daily consumption of capsaicinoids may contribute to weight management through reductions in energy intake. Subsequently, there may be potential for capsaicinoids to be used as long-term, natural weight-loss aids. Further long-term randomised trials are now needed to investigate these effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Diffusion-Weighted Magnetic Resonance Imaging to Evaluate Major Salivary Gland Function Before and After Radiotherapy

    SciTech Connect

    Dirix, Piet Keyzer, Frederik de; Vandecaveye, Vincent; Stroobants, Sigrid; Hermans, Robert; Nuyts, Sandra

    2008-08-01

    Purpose: To evaluate diffusion-weighted (DW)-MRI as a noninvasive tool to investigate major salivary gland function before and after radiotherapy (RT) for head and neck cancer (HNC). Methods and Materials: DW-MRI was performed in 8 HNC patients before and after parotid-sparing RT (mean dose to the contralateral parotid gland <26 Gy). A DW sequence was performed once at rest and then repeated continuously during salivary stimulation. Apparent diffusion coefficient (ADC) maps for both parotid and submandibular glands were calculated. Findings were compared with salivary gland scintigraphy. Results: Before RT, the mean ADC value at rest was significantly lower in the parotid than in the submandibular glands. During the first 5 min of stimulation, the ADC value of the salivary glands showed a decrease, followed by a steady increase until a peak ADC, significantly higher than the baseline value, was reached after a median of 17 min. The baseline ADC value at rest was significantly higher after RT than before RT in the nonspared salivary glands but not in the spared parotid glands. In the contralateral parotid glands, the same response was seen as before RT. This pattern was completely lost in the nonspared glands. These results corresponded with remaining or loss of salivary function, respectively, as confirmed by salivary gland scintigraphy. Conclusions: Diffusion-weighted-MRI allows noninvasive evaluation of functional changes in the major salivary glands after RT and is a promising tool for investigating radiation-induced xerostomia.

  11. Feasibility of in vivo quantitative magnetic resonance imaging with diffusion weighted imaging, T2-weighted relaxometry, and diffusion tensor imaging in a clinical 3 tesla magnetic resonance scanner for the acute traumatic spinal cord injury of rats: technical note.

    PubMed

    Mondragon-Lozano, Rodrigo; Diaz-Ruiz, Araceli; Ríos, Camilo; Olayo Gonzalez, Roberto; Favila, Rafael; Salgado-Ceballos, Hermelinda; Roldan-Valadez, Ernesto

    2013-09-15

    Prospective longitudinal study. To verify the feasibility of performing in vivo quantitative magnetic resonance imaging evaluation of moderate traumatic spinal cord injury (SCI) in rats using a clinical 3T scanner. Animal models of human diseases are essential for translational medicine. Potential treatments of SCI are evaluated in 2 ways: anatomical and functional. Advanced magnetic resonance sequences allow a noninvasive assessment of the spinal cord depicting both. This study describes and validates a very reproducible, feasible, affordable, and reliable method, designed to be applied in commercial 3T equipment, using a novel stereotactic device for spinal cord, leading to a readily available assessment of the progression of damage generated after traumatic SCI in rats. Four Long-Evans female rats were injured with a New York University weight-drop device to produce the SCI by contusion at thoracic level 10. All animals were placed in a fixation system, using a commercial wrist antenna to obtain magnetic resonance imaging data of the relaxometry time, apparent diffusion coefficient, and fractional anisotropy. Three sets of data obtained before SCI and 1 and 4 weeks after injury were compared. The data showed a progressive decline in fractional anisotropy measurements after SCI comparing baseline versus the 1-week period (P < 0.001) and baseline versus the 4-week period (P < 0.019), with a significant progressive increase in apparent diffusion coefficient values and T2 after SCI only in the baseline versus the 4-week period (P < 0.045 and P < 0.024, respectively). Our results helped us to validate a novel method to acquire highly reproducible and reliable quantitative biomarkers of traumatic SCI in vivo by using a 3T clinical MR scanner coupled with a novel stereotactic device for rats. N/A.

  12. High-performance fluorescence-encoded magnetic microbeads as microfluidic protein chip supports for AFP detection.

    PubMed

    Gong, Xiaoqun; Yan, Huan; Yang, Jiumin; Wu, Yudong; Zhang, Jian; Yao, Yingyi; Liu, Ping; Wang, Huiquan; Hu, Zhidong; Chang, Jin

    2016-10-05

    Fluorescence-encoded magnetic microbeads (FEMMs), with the fluorescence encoding ability of quantum dots (QDs) and magnetic enrichment and separation functions of Fe3O4 nanoparticles, have been widely used for multiple biomolecular detection as microfluidic protein chip supports. However, the preparation of FEMMs with long-term fluorescent encoding and immunodetection stability is still a challenge. In this work, we designed a novel high-temperature chemical swelling strategy. The QDs and Fe3O4 nanoparticles were effectively packaged into microbeads via the thermal motion of the polymer chains and the hydrophobic interaction between the nanoparticles and microbeads. The FEMMs obtained a highly uniform fluorescent property and long-term encoding and immunodetection stability and could be quickly magnetically separated and enriched. Then, the QD-encoded magnetic microbeads were applied to alpha fetoprotein (AFP) detection via sandwich immunoreaction. The properties of the encoded microspheres were characterized using a self-designed detecting apparatus, and the target molecular concentration in the sample was also quantified. The results suggested that the high-performance FEMMs have great potential in the field of biomolecular detection. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Effect of incorporating cooling channels into the coil support structure of the TPX toroidal field magnet

    SciTech Connect

    Lvovsky, Y.M.; Neeley, G.W.; Tong, Wei

    1996-12-31

    Toroidal field (TF) magnets for the Tokamak Physics experiment (TPX) include superconducting cable-in conduit conductor (CICC) coils encased in a stainless steel support structure, which receives most of the heat generated in the magnet during operation. An efficient cooling of the structure is necessary to intercept the heat which otherwise would reach the winding pack and reduce temperature margin of the superconductor. Optimal cooling arrangement requires joint (coil+structure) analysis which considers thermal coupling between the winding pack and the structure. A joint steady-state 3-D thermal-hydraulic model for toroidal field magnets is presented. It consists of the two submodels, coupled through iterative runs. First submodel analyzes one-dimensional helium flow in CICC double pancake accounting for thermal coupling between turns. Second is a finite element model for the support structure, represented by 12 sections along the circumference of the coil. Model has demonstrated fast convergence and capabilities to analyze heat flux distribution in the winding pack and structure. Temperature profile in CICC and heat absorbed by case cooling channels are presented.

  14. Three-Tesla magnetic resonance elastography for hepatic fibrosis: Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

    PubMed Central

    Park, Hee Sun; Kim, Young Jun; Yu, Mi Hye; Choe, Won Hyeok; Jung, Sung Il; Jeon, Hae Jeong

    2014-01-01

    AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging. METHODS: Forty-two patients were included in the study. On MRE, mean stiffness values were measured on the elastograms in kilopascals. The apparent diffusion coefficient (ADC) of the liver was measured using DWI. On gadoxetic acid enhanced MR, the contrast enhancement index (CEI) was calculated as signal intensity (SI)post/SIpre, where SIpost is liver-to-muscle SI ratio on hepatobiliary phase images and SIpre is that on nonenhanced images. Correlation between aspartate aminotransferase to the platelet ratio index (APRI) and three MR parameters was assessed. Each MR parameter was compared between a hepatic fibrosis (HF) group and non-hepatic fibrosis (nHF) group. RESULTS: Liver stiffness showed strong positive correlation with APRI [Spearman correlation coeffiecient (r) = 0.773, P < 0.0001], while ADC and CEI showed weak or prominent negative correlation (r = -0.28 and -0.321, respectively). In the HF group, only liver stiffness showed strong correlation with APRI (r = 0.731, P < 0.0001). Liver stiffness, ADC, and APRI were significantly different between the HF group and nHF group. CONCLUSION: MRE at 3-Tesla could be a feasible method for the assessment of hepatic fibrosis. PMID:25516671

  15. Whole-body diffusion-weighted magnetic resonance imaging: current evidence in oncology and potential role in colorectal cancer staging.

    PubMed

    Lambregts, Doenja M J; Maas, Monique; Cappendijk, Vincent C; Prompers, Leonne M; Mottaghy, Felix M; Beets, Geerard L; Beets-Tan, Regina G H

    2011-09-01

    Tumour staging in cancer patients generally entails a multimodality imaging approach. Whole-body (WB) imaging techniques may, however, be more time- and cost-effective than a multimodality approach. 2-fluorine-18-fluoro-2-deoxy-D-glucose positron emission tomography (18FDG-PET), computed tomography (CT) and hybrid positron emission tomography and computed tomography (PET/CT) are the most established WB modalities, although new techniques, amongst which diffusion-weighted magnetic resonance imaging (DWI), are emerging. This review aims to evaluate the current evidence for WB-DWI in oncology, to discuss its potential for the WB staging of (colo)rectal cancer and to relate it to the established WB techniques.

  16. Diffusion-weighted magnetic resonance imaging of the musculoskeletal system: an emerging technology with potential to impact clinical decision making.

    PubMed

    Beattie, Paul F

    2011-11-01

    Diffusion-weighted imaging (DWI) is an application of magnetic resonance imaging that allows the measurement of water movement within and between tissues. Originally developed as a way of detecting early signs of stroke or brain disease, DWI is now being used to study physiologic events within the musculoskeletal system. The accurate measurement of water diffusion can provide important information regarding tissue responses associated with trauma and disease, as well as offer insight toward the mechanism by which physical therapy interventions affect tissues. The purpose of this paper is to discuss the rationale for DWI and its potential clinical and research applications for patients with musculoskeletal disorders. Specific examples of the use of DWI for patients with painful spinal disorders are used as illustrations.

  17. [The clinical application of hydrogen magnetic resonance spectroscopy combining with diffusion weight imaging in brain gliomas grading].

    PubMed

    Xu, Shengsheng; Ouyang, Yu; Luo, Tianyou; Zeng, Yongming; Zhou, Xiangping; Xiao, Jiahe

    2011-06-01

    The present study was aimed to investigate the function of diffusion weight imaging (DWI) combining with magnetic resonance spectroscopy (MRS) in the grading of brain gliomas. 12 cases low grade and 17 cases high grade of brain gliomas patients were examined with DWI and MRS, with all tumors confirmed by pathology in advance. The apparent diffusion coefficient (ADC) values, their corresponding metabolite ratios of Cho/Cr, Cho/NAA and tumor cellularities of tumor solid enhanced parts were measured. The ratios of Cho/Cr and Cho/NAA and their corresponding ADC values had significant differences between their high and low grade gliomas values, respectively. The ADC values demonstrated a negative correlation with Cho/Cr, Cho/NAA, and a significant negative correlated with Cho/Cr. And the ADC values demonstrated strong negative correlations with tumor cellularities. DWI combining with MRS could provide more valuable information in evaluating gliomas grading.

  18. Design of a superconducting 28 GHz ion source magnet for FRIB using a shell-based support structure

    SciTech Connect

    Felice, H.; Rochepault, E.; Hafalia, R.; Caspi, S.; Dietderich, D. R.; Prestemon, S. O.; Machicoane, G.; Pozdeyev, E.; Bultman, N.; Rao, X.

    2014-12-05

    The Superconducting Magnet Program at the Lawrence Berkeley National Laboratory (LBNL) is completing the design of a 28 GHz NbTi ion source magnet for the Facility for Rare Isotope Beams (FRIB). The design parameters are based on the parameters of the ECR ion source VENUS in operation at LBNL since 2002 featuring a sextupole-in-solenoids configuration. Whereas most of the magnet components (such as conductor, magnetic design, protection scheme) remain very similar to the VENUS magnet components, the support structure of the FRIB ion source uses a different concept. A shell-based support structure using bladders and keys is implemented in the design allowing fine tuning of the sextupole preload and reversibility of the magnet assembly process. As part of the design work, conductor insulation scheme, coil fabrication processes and assembly procedures are also explored to optimize performance. We present the main features of the design emphasizing the integrated design approach used at LBNL to achieve this result.

  19. HASTE diffusion-weighted 3-Tesla magnetic resonance imaging in the diagnosis of primary and relapsing cholesteatoma.

    PubMed

    Pizzini, Francesca B; Barbieri, Franco; Beltramello, Alberto; Alessandrini, Franco; Fiorino, Francesco

    2010-06-01

    To evaluate the value of half-Fourier acquisition single-shot turbo-spin-echo diffusion-weighted magnetic resonance imaging (HASTE DW MRI) using a 3-Tesla (3T) unit in the diagnosis of primary and relapsing cholesteatoma. Retrospective observational investigation. Tertiary referral center. Seventeen patients suspected of having a primary cholesteatoma without clear clinical evidence of the lesion, and 13 patients who were candidates to a second-stage tympanoplasty to rule out a relapsing cholesteatoma or reconstruct the ossicular chain were investigated. All patients were scanned in a 3T scanner with a 4-channel head coil using T2 HASTE DW MRI technique sequences in axial and coronal planes covering the middle ear and mastoid regions. Images were considered positive for cholesteatoma in the presence of a hyperintense, patchy-like lesion in the petrous bone. Images showed a high signal intensity suggestive of primary cholesteatoma in 10 of 17 patients and of relapsing cholesteatoma in 7 of 13 patients. Of the 17 subjects, 15 with positive MRI findings were operated on, and the presence of cholesteatoma (ranging from 2 to 20 mm in size) was confirmed at surgery. Of the 13 subjects shown to be negative on HASTE DW MRI for cholesteatoma, 11 were operated on and were all confirmed to be cholesteatoma-free. Half-Fourier acquisition single-shot turbo-spin-echo diffusion-weighted magnetic resonance imaging technique, using a 3T unit, may be a diagnostic tool for a rapid and highly reliable discrimination between cholesteatomatous and noncholesteatomatous tissue in the middle ear, with 100% of positive and negative predictive values.

  20. Stabilizing Gyroscopic Modes in Magnetic-Bearing-Supported Flywheels by Using Cross-Axis Proportional Gains

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.; Kascak, Albert F.; Jansen, Ralph H.; Dever, Timothy P.; Duffy, Kirsten P.

    2006-01-01

    For magnetic-bearing-supported high-speed rotating machines with significant gyroscopic effects, it is necessary to stabilize forward and backward tilt whirling modes. Instability or low damping of these modes can prevent the attainment of desired shaft speed. We show analytically that both modes can be stabilized by using cross-axis proportional gains and high- and low-pass filters in the magnetic bearing controller. Furthermore, at high shaft speeds, where system phase lags degrade the stability of the forward-whirl mode, a phasor advance of the control signal can partially counteract the phase lag. In some range of high shaft speed, the derivative gain for the tilt modes (essential for stability for slowly rotating shafts) can be removed entirely. We show analytically how the tilt eigenvalues depend on shaft speed and on various controller feedback parameters.

  1. Effects of Maternal Pregnancy Intention, Depressive Symptoms and Social Support on Risk of Low Birth Weight: A Prospective Study from Southwestern Ethiopia

    PubMed Central

    Wado, Yohannes Dibaba; Afework, Mesganaw Fantahun; Hindin, Michelle J.

    2014-01-01

    Background Low birth weight (LBW) is the principal risk factor for neonatal and infant mortality in developing countries. This study examines the effects of unwanted pregnancy, prenatal depression and social support on the risk of low birth weight in rural southwestern Ethiopia. We hypothesized that unwanted pregnancy and prenatal depression increase the risk of low birth weight, while social support mediates this association. Methods Data for the study comes from a prospective study in which women were followed from pregnancy through to delivery. Six hundred twenty two women were followed and 537 birth weights were measured within 72 hours. Multivariable log binomial regression was used to model the risk of low birth weight. Results The mean birth weight was 2989 grams (SD±504 grams), and the incidence of LBW was 17.88%. The mean birth weight of babies after unwanted pregnancy was 114 g lower compared to births from intended pregnancy. Similarly, mean birth weight for babies among women with symptoms of antenatal depression was 116 grams lower. Results of unadjusted log-binomial regression showed that unwanted pregnancy, prenatal depression and social support were associated with LBW. The relationship between antenatal depressive symptoms and LBW was mediated by the presence of social support, while the association between LBW and unwanted pregnancy remained after multivariable adjustment. Conclusion The incidence of low birth weight is high in the study area. Poverty, nonuse of antenatal care, low social support and unwanted pregnancy contribute to this high incidence of low birth weight. Hence, identifying women’s pregnancy intention during antenatal care visits, and providing appropriate counseling and social support will help improve birth outcomes. PMID:24848269

  2. Assessment of acute thermal damage volumes in muscle using magnetization-prepared 3D T2 -weighted imaging following MRI-guided high-intensity focused ultrasound therapy.

    PubMed

    Staruch, Robert M; Nofiele, Joris; Walker, Jamie; Bing, Chenchen; Madhuranthakam, Ananth J; Bailey, April; Kim, Young-Sun; Chhabra, Avneesh; Burns, Dennis; Chopra, Rajiv

    2017-08-01

    To evaluate magnetization-prepared 3D T2 -weighted magnetic resonance imaging (MRI) measurements of acute tissue changes produced during ablative MR high-intensity focused ultrasound (MR-HIFU) exposures. A clinical MR-HIFU system (3T) was used to generate thermal lesions (n = 24) in the skeletal muscles of three pigs. T1 -weighted, 2D T2 -weighted, and magnetization-prepared 3D T2 -weighted sequences were acquired before and after therapy to evaluate tissue changes following ablation. Tissues were harvested shortly after imaging, fixed in formalin, and gross-sectioned. Select lesions were processed into whole-mount sections. Lesion dimensions for each imaging sequence (length, width) and for gross sections (diameter of lesion core and rim) were assessed by three physicists. Contrast-to-background ratio between lesions and surrounding muscle was compared. Lesion dimensions on T1 and 2D T2 -weighted imaging sequences were well correlated (R(2) ∼0.7). The contrast-to-background ratio between lesion and surrounding muscle was 7.4 ± 2.4 for the magnetization-prepared sequence versus 1.7 ± 0.5 for a conventional 2D T2 -weighted acquisition, and 7.0 ± 2.9 for a contrast-enhanced T1 -weighted sequence. Compared with diameter measured on gross pathology, all imaging sequences overestimated the lesion core by 22-33%, and underestimated the lesion rim by 6-13%. After MR-HIFU exposures, measurements of the acute thermal damage patterns in muscle using a magnetization-prepared 3D T2 -weighted imaging sequence correlate with 2D T2 -weighted and contrast-enhanced T1 -weighted imaging, and all agree well with histology. The magnetization-prepared sequence offers positive tissue contrast and does not require IV contrast agents, and may provide a noninvasive imaging evaluation of the region of acute thermal injury at multiple times during HIFU procedures. 1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:354-364. © 2017 International Society for

  3. Electronic and magnetic properties of silicon supported organometallic molecular wires: a density functional theory (DFT) study

    NASA Astrophysics Data System (ADS)

    Liu, Xia; Tan, Yingzi; Li, Xiuling; Wu, Xiaojun; Pei, Yong

    2015-08-01

    The electronic and magnetic properties of transition metal (TM = Sc, Ti, V, Cr and Mn) atom incorporated single and double one-dimensional (1D) styrene molecular wires confined on the hydrogen-terminated Si(100) surface are explored for the first time by means of spin-polarized density functional theory, denoted as Si-[TM(styrene)]. It is unveiled that TM atoms bind asymmetrically to the adjacent phenyl rings, which leads to novel electronic and magnetic properties in stark contrast to the well-studied gas phase TM-benzene molecular wires. Si-[Mn(styrene)]∞ and Si-[Cr(styrene)]∞ single molecular wires (SMWs) are a ferromagnetic semiconductor and half metal, respectively. Creation of H-atom defects on the silicon surface can introduce an impurity metallic band, which leads to novel half-metallic magnetism of a Si-[Mn(styrene)]∞ system. Moreover, double molecular wires (DMWs) containing two identical or hetero SMWs are theoretically designed. The [Mn(styrene)]∞-[Cr(styrene)]∞ DMW exhibits half-metallic magnetism where the spin-up and spin-down channels are contributed by two single molecular wires. Finally, we demonstrate that introducing a TM-defect may significantly affect the electronic structure and magnetic properties of molecular wires. These studies provide new insights into the structure and properties of surface supported 1-D sandwiched molecular wires and may inspire the future experimental synthesis of substrate confined organometallic sandwiched molecular wires.The electronic and magnetic properties of transition metal (TM = Sc, Ti, V, Cr and Mn) atom incorporated single and double one-dimensional (1D) styrene molecular wires confined on the hydrogen-terminated Si(100) surface are explored for the first time by means of spin-polarized density functional theory, denoted as Si-[TM(styrene)]. It is unveiled that TM atoms bind asymmetrically to the adjacent phenyl rings, which leads to novel electronic and magnetic properties in stark contrast to

  4. Rim sign in breast lesions on diffusion-weighted magnetic resonance imaging: diagnostic accuracy and clinical usefulness.

    PubMed

    Kang, Bong Joo; Lipson, Jafi Alyssa; Planey, Katie RoseMary; Zackrisson, Sophia; Ikeda, Debra M; Kao, Jennifer; Pal, Sunita; Moran, Catherine J; Daniel, Bruce Lewis

    2015-03-01

    To investigate the diagnostic accuracy and clinical usefulness of the rim sign in breast lesions observed in diffusion-weighted magnetic resonance imaging (DWI). The magnetic resonance imaging (MRI) findings of 98 pathologically confirmed lesions (62 malignant and 36 benign) in 84 patients were included. Five breast radiologists were asked to independently review the breast MRI results, to grade the degree of high peripheral signal, the "rim sign," in the DWI, and to confirm the mean apparent diffusion coefficient (ADCmean ) values. We analyzed the diagnostic accuracy and compared the consensus (when ≥ 4 of 5 independent reviewers agreed) results of the rim sign with the ADCmean values. Additionally, we evaluated the correlation between the dynamic contrast-enhanced (DCE)-MRI morphologic appearance and DWI rim sign. According to the consensus results, the rim sign in DWI was observed on 59.7% of malignant lesions and 19.4% of benign lesions. The sensitivity, specificity, and area under the curve (AUC) value for the rim sign in DWI were 59.7%, 80.6%, and 0.701, respectively. The sensitivity, specificity, and AUC value for the ADCmean value (criteria ≤ 1.46 × 10(-3) mm(2) /sec) were 82.3%, 63.9%, and 0.731, respectively. Based on consensus, no correlation was observed between the DCE-MRI and DWI rim signs. In DWI, a high-signal rim is a valuable morphological feature for improving specificity in DWI. © 2014 Wiley Periodicals, Inc.

  5. Cuckoo Search with Lévy Flights for Weighted Bayesian Energy Functional Optimization in Global-Support Curve Data Fitting

    PubMed Central

    Gálvez, Akemi; Iglesias, Andrés; Cabellos, Luis

    2014-01-01

    The problem of data fitting is very important in many theoretical and applied fields. In this paper, we consider the problem of optimizing a weighted Bayesian energy functional for data fitting by using global-support approximating curves. By global-support curves we mean curves expressed as a linear combination of basis functions whose support is the whole domain of the problem, as opposed to other common approaches in CAD/CAM and computer graphics driven by piecewise functions (such as B-splines and NURBS) that provide local control of the shape of the curve. Our method applies a powerful nature-inspired metaheuristic algorithm called cuckoo search, introduced recently to solve optimization problems. A major advantage of this method is its simplicity: cuckoo search requires only two parameters, many fewer than other metaheuristic approaches, so the parameter tuning becomes a very simple task. The paper shows that this new approach can be successfully used to solve our optimization problem. To check the performance of our approach, it has been applied to five illustrative examples of different types, including open and closed 2D and 3D curves that exhibit challenging features, such as cusps and self-intersections. Our results show that the method performs pretty well, being able to solve our minimization problem in an astonishingly straightforward way. PMID:24977175

  6. Cuckoo search with Lévy flights for weighted Bayesian energy functional optimization in global-support curve data fitting.

    PubMed

    Gálvez, Akemi; Iglesias, Andrés; Cabellos, Luis

    2014-01-01

    The problem of data fitting is very important in many theoretical and applied fields. In this paper, we consider the problem of optimizing a weighted Bayesian energy functional for data fitting by using global-support approximating curves. By global-support curves we mean curves expressed as a linear combination of basis functions whose support is the whole domain of the problem, as opposed to other common approaches in CAD/CAM and computer graphics driven by piecewise functions (such as B-splines and NURBS) that provide local control of the shape of the curve. Our method applies a powerful nature-inspired metaheuristic algorithm called cuckoo search, introduced recently to solve optimization problems. A major advantage of this method is its simplicity: cuckoo search requires only two parameters, many fewer than other metaheuristic approaches, so the parameter tuning becomes a very simple task. The paper shows that this new approach can be successfully used to solve our optimization problem. To check the performance of our approach, it has been applied to five illustrative examples of different types, including open and closed 2D and 3D curves that exhibit challenging features, such as cusps and self-intersections. Our results show that the method performs pretty well, being able to solve our minimization problem in an astonishingly straightforward way.

  7. Youth dietary intake and weight status: healthful neighborhood food environments enhance the protective role of supportive family home environments.

    PubMed

    Berge, Jerica M; Wall, Melanie; Larson, Nicole; Forsyth, Ann; Bauer, Katherine W; Neumark-Sztainer, Dianne

    2014-03-01

    The aim of this study is to investigate individual and joint associations of the home environment and the neighborhood built environment with adolescent dietary patterns and body mass index (BMI) z-score. Racially/ethnically and socioeconomically diverse adolescents (n=2682; 53.2% girls; mean age14.4 years) participating in the EAT 2010 (Eating and Activity in Teens) study completed height and weight measurements and surveys in Minnesota middle and high schools. Neighborhood variables were measured using Geographic Information Systems data. Multiple regressions of BMI z-score, fruit and vegetable intake, and fast food consumption were fit including home and neighborhood environmental variables as predictors and also including their interactions to test for effect modification. Supportive family environments (i.e., higher family functioning, frequent family meals, and parent modeling of healthful eating) were associated with higher adolescent fruit and vegetable intake, lower fast food consumption, and lower BMI z-score. Associations between the built environment and adolescent outcomes were fewer. Interaction results, although not all consistent, indicated that the relationship between a supportive family environment and adolescent fruit and vegetable intake and BMI was enhanced when the neighborhood was supportive of healthful behavior. Public health interventions that simultaneously improve both the home environment and the neighborhood environment of adolescents may have a greater impact on adolescent obesity prevention than interventions that address one of these environments alone.

  8. Test Results of LARP Nb3Sn Quadrupole Magnets Using a Shell-based Support Structure (TQS)

    SciTech Connect

    Caspi, S.; Dietderich, D. R.; Felice, H.; Ferracin, P.; Hafalia, R.; Hannaford, C. R.; Lietzke, A. F.; Lizarazo, J.; Sabbi, G.; Wang, X.; Ghosh, A.; Wanderer, P.; Ambrosio, G.; Barzi, E.; Bossert, R.; Chlachidze, G.; Feher, S.; Kashikhin, V. V.; Lamm, M.; Tartaglia, M. A.; Zlobin, A. V.; Bajko, M.; Bordini, B.; DeRijk, G.; Giloux, C.; Karppinen, M.; Perez, J. C.; Rossi, L.; Siemko, A.; Todesco, E.

    2008-08-17

    Among the magnet development program of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider luminosity upgrade, six quadrupole magnets were built and tested using a shell based key and bladder technology (TQS). The 1 m long 90 mm aperture magnets are part o fthe US LHC Accelerator Research Program (LARP) aimed at demonstrating Nb{sub 3}Sn technology by the year 2009, of a 3.6 m long magnet capable of achieving 200 T/m. In support of the LARP program the TQS magnets were tested at three different laboratories, LBNL, FNAL and CERN and while at CERN a technology-transfer and a four days magnet disassembly and reassembly were included. This paper summarizes the fabrication, assembly, cool-down and test results of the six magnets and compres measruements with design expectations.

  9. Stability Limits of a PD Controller for a Flywheel Supported on Rigid Rotor and Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Kascak, Albert F.; Brown, Gerald V.; Jansen, Ralph H.; Dever, TImothy P.

    2006-01-01

    Active magnetic bearings are used to provide a long-life, low-loss suspension of a high-speed flywheel rotor. This paper describes a modeling effort used to understand the stability boundaries of the PD controller used to control the active magnetic bearings on a high speed test rig. Limits of stability are described in terms of allowable stiffness and damping values which result in stable levitation of the nonrotating rig. Small signal stability limits for the system is defined as a nongrowth in vibration amplitude of a small disturbance. A simple mass-force model was analyzed. The force resulting from the magnetic bearing was linearized to include negative displacement stiffness and a current stiffness. The current stiffness was then used in a PD controller. The phase lag of the control loop was modeled by a simple time delay. The stability limits and the associated vibration frequencies were measured and compared to the theoretical values. The results show a region on stiffness versus damping plot that have the same qualitative tendencies as experimental measurements. The resulting stability model was then extended to a flywheel system. The rotor dynamics of the flywheel was modeled using a rigid rotor supported on magnetic bearings. The equations of motion were written for the center of mass and a small angle linearization of the rotations about the center of mass. The stability limits and the associated vibration frequencies were found as a function of nondimensional magnetic bearing stiffness and damping and nondimensional parameters of flywheel speed and time delay.

  10. Diffusion-Weighted Magnetic Resonance Imaging for Therapy Response Monitoring and Early Treatment Prediction of Photothermal Therapy.

    PubMed

    Fu, Guifeng; Zhu, Lei; Yang, Kai; Zhuang, Rongqiang; Xie, Jin; Zhang, Fan

    2016-03-02

    Photothermal therapy (PTT) as a relatively new cancer treatment method has attracted worldwide attention. Previous research on PTT has focused on its therapy efficiency and selectivity. The early prognosis of PTT, which is pivotal for the assessment of the treatment and the therapy stratification, however, has been rarely studied. In the present study, we investigated diffusion-weighted magnetic resonance imaging (DW-MRI) as a tool for therapy monitoring and early prognosis of PTT. To this end, we injected PEGylated graphene oxide (GO-PEG) or iron oxide deposited graphene oxide (GO-IONP-PEG) to 4T1 tumor models and irradiated the tumors at different drug-light intervals to induce PTT. For GO-IONP-PEG injected animals, we also included therapy arms where an external magnetic field was applied to the tumors to improve the delivery of the nanoparticle transducers. DW-MRI was performed at different time points after PTT and the tumor apparent diffusion coefficients (ADCs) were analyzed and compared. Our studies show that photothermal agents, magnetic guidance, and drug-light intervals can all affect PTT treatment efficacy. Impressively, ADC value changes at early time points after PTT (less than 48 h) were found to be well-correlated with tumor growth suppression that was apparent days or weeks later. The changes were most sensitive to conditions that can extend the survival for more than 4 weeks, in which cases the 48 h ADC values were increased by more than 80%. These studies demonstrate for the first time that DW-MRI can be an accurate prognosis tool for PTT, suggesting an important role it can play in the future PTT evaluation and clinical translation of the modality.

  11. A Magnetic Soft Endoscopic Capsule-Inflated Intragastric Balloon for Weight Management

    PubMed Central

    Do, Thanh Nho; Ho, Khek Yu; Phee, Soo Jay

    2016-01-01

    Overweight and obesity have been identified as a cause of high risk diseases like diabetes and cancer. Although conventional Intragastric Balloons (IGBs) have become an efficient and less invasive method for overweight and obesity treatment, the use of conventional tools such as catheter or endoscope to insert and remove the IGBs from the patient’s body causes nausea, vomiting, discomfort, and even gastric mucous damage. To eliminate these drawbacks, we develop a novel magnetic soft capsule device with gas-filled balloon inflation. The balloon is made from a thin and biocompatible material that can be inflated to a desired volume using biocompatible effervescent chemicals. In addition, both the outer balloon and inner capsule are designed to be soft and chemical resistance. The soft capsule shell is fabricated using scaffold-solvent approach while the outer balloon utilizes a novel fabrication approach for 3D spherical structure. A prototype of the proposed capsule and balloon is given. Experiments are successfully carried out in stimulated gastric environment and fresh porcine stomach to validate the effectiveness and reliability of the proposed approach. PMID:28000756

  12. Developments in diffusion weighted magnetic resonance imaging (MRI) with applications to neural tissue

    NASA Astrophysics Data System (ADS)

    Ozarslan, Evren

    Translational diffusion of water within biological tissue can be measured noninvasively using magnetic resonance imaging techniques. Diffusion imaging of neural tissue can provide very valuable information about the tissue microstructure because of its sensitivity to the molecular motion in length scales much smaller than the resolution of the images and similar to the dimensions of the cells. Diffusion attenuated multidirectional signal can be utilized to provide information about the local orientation of highly structured environments. However, the most common approach that has been used for this purpose (diffusion tensor imaging) assumes orientational homogeneity within the region. This assumption can lead to incorrect estimations of fiber orientations and anisotropy values. In order to overcome this problem, we have proposed to use Cartesian tensors of rank higher than 2 to model the measured diffusion coefficients. This approach enables the calculation of more accurate anisotropy values which is of great importance in clinical studies. We have also achieved the resolution of multiple orientations using higher rank tensors as well as through a more direct approach in which we generate the Laplace series coefficients of the probability function on the surface of a sphere. The methods we present are applicable to data that can be acquired using clinically available scanners in short time frames.

  13. Impact of measurement parameters on apparent diffusion coefficient quantification in diffusion-weighted-magnetic resonance imaging.

    PubMed

    Schmidt, Holger; Gatidis, Sergios; Schwenzer, Nina F; Martirosian, Petros

    2015-01-01

    The scope of this work was to systematically evaluate the reproducibility of diffusion-weighted imaging and the impact of b values used for apparent diffusion coefficient (ADC) calculation as well as the echo time (TE) on the resulting ADC in phantom studies. We attempted to find a minimum upper b value needed for reliable ADC measurements. In addition, we were able to investigate these impacts not only for different diffusivities but also for different T2 relaxation times. The influence of different b values on ADC calculations for different organs was also assessed in a volunteer study. Diffusion-weighted imaging of a phantom consisting of 16 compartments with combinations of 4 different diffusivities and 4 different T2 relaxation times was conducted 5 times using 11 b values (0-1000 s/mm) and 5 different TEs. Apparent diffusion coefficient was calculated from the 16 compartment regions of interest using 42 different combinations of b values. Reproducibility of ADC was assessed from the coefficient of variation of the 5 measurements. The ADC stability was determined from a voxel-based coefficient of variation (CVsta) and the signal-to-noise ratio (SNR) to find the minimum upper b values for a reliable ADC quantification. The influence of TE on ADC quantification was assessed for 9 different b value combinations. The influence of 9 different b value combinations on ADC was evaluated by a region of interest analysis of 7 organs in 12 volunteers. The found coefficient of variation was between 10.2% and 1.4%, decreasing with increasing upper b value and increasing diffusivities. Accordingly, CVsta and SNR showed the same trend. Using an upper b value of 600 s/mm gives already reliable ADC results showing a maximum CVsta of 7.5%, whereas an upper b value of 1000 s/mm revealed a maximum CVsta of 5.5%. Values of ADC reduced with increasing upper b value in phantom as well as in human data. Apparent diffusion coefficient also reduced with increasing TE and tended to

  14. High molecular weight chitosan derivative polymeric micelles encapsulating superparamagnetic iron oxide for tumor-targeted magnetic resonance imaging

    PubMed Central

    Xiao, Yunbin; Lin, Zuan Tao; Chen, Yanmei; Wang, He; Deng, Ya Li; Le, D Elizabeth; Bin, Jianguo; Li, Meiyu; Liao, Yulin; Liu, Yili; Jiang, Gangbiao; Bin, Jianping

    2015-01-01

    Magnetic resonance imaging (MRI) contrast agents based on chitosan derivatives have great potential for diagnosing diseases. However, stable tumor-targeted MRI contrast agents using micelles prepared from high molecular weight chitosan derivatives are seldom reported. In this study, we developed a novel tumor-targeted MRI vehicle via superparamagnetic iron oxide nanoparticles (SPIONs) encapsulated in self-aggregating polymeric folate-conjugated N-palmitoyl chitosan (FAPLCS) micelles. The tumor-targeting ability of FAPLCS/SPIONs was demonstrated in vitro and in vivo. The results of dynamic light scattering experiments showed that the micelles had a relatively narrow size distribution (136.60±3.90 nm) and excellent stability. FAPLCS/SPIONs showed low cytotoxicity and excellent biocompatibility in cellular toxicity tests. Both in vitro and in vivo studies demonstrated that FAPLCS/SPIONs bound specifically to folate receptor-positive HeLa cells, and that FAPLCS/SPIONs accumulated predominantly in established HeLa-derived tumors in mice. The signal intensities of T2-weighted images in established HeLa-derived tumors were reduced dramatically after intravenous micelle administration. Our study indicates that FAPLCS/SPION micelles can potentially serve as safe and effective MRI contrast agents for detecting tumors that overexpress folate receptors. PMID:25709439

  15. High molecular weight chitosan derivative polymeric micelles encapsulating superparamagnetic iron oxide for tumor-targeted magnetic resonance imaging.

    PubMed

    Xiao, Yunbin; Lin, Zuan Tao; Chen, Yanmei; Wang, He; Deng, Ya Li; Le, D Elizabeth; Bin, Jianguo; Li, Meiyu; Liao, Yulin; Liu, Yili; Jiang, Gangbiao; Bin, Jianping

    2015-01-01

    Magnetic resonance imaging (MRI) contrast agents based on chitosan derivatives have great potential for diagnosing diseases. However, stable tumor-targeted MRI contrast agents using micelles prepared from high molecular weight chitosan derivatives are seldom reported. In this study, we developed a novel tumor-targeted MRI vehicle via superparamagnetic iron oxide nanoparticles (SPIONs) encapsulated in self-aggregating polymeric folate-conjugated N-palmitoyl chitosan (FAPLCS) micelles. The tumor-targeting ability of FAPLCS/SPIONs was demonstrated in vitro and in vivo. The results of dynamic light scattering experiments showed that the micelles had a relatively narrow size distribution (136.60±3.90 nm) and excellent stability. FAPLCS/SPIONs showed low cytotoxicity and excellent biocompatibility in cellular toxicity tests. Both in vitro and in vivo studies demonstrated that FAPLCS/SPIONs bound specifically to folate receptor-positive HeLa cells, and that FAPLCS/SPIONs accumulated predominantly in established HeLa-derived tumors in mice. The signal intensities of T2-weighted images in established HeLa-derived tumors were reduced dramatically after intravenous micelle administration. Our study indicates that FAPLCS/SPION micelles can potentially serve as safe and effective MRI contrast agents for detecting tumors that overexpress folate receptors.

  16. Predicting Mortality in Patients With “Malignant” Middle Cerebral Artery Infarction Using Susceptibility-Weighted Magnetic Resonance Imaging

    PubMed Central

    Chao, Shu-Ping; Chen, Chia-Yuen; Tsai, Fong Y.; Chan, Wing P.; Chen, Chin-I

    2016-01-01

    Abstract To evaluate malignant middle cerebral artery (MCA) infarction (defined as space-occupying edema in more than 50% to 75% of the MCA territory) on magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) sequence and assess the usefulness of SWI findings, diffusion-weighted imaging (DWI) findings, and apparent diffusion coefficient (ADC) as predictors of clinical outcome. Data from 16 patients with large MCA infarction previously admitted to our institution between December 2009 and October 2012 were retrospectively collected and analyzed. Within 7 days after stroke onset, 1 neurologist and 1 neuroradiologist estimated the area of infarction on DWI/ADC and extent of prominent vessel sign (PVS) on SWI images using the Stroke Program Early MR Score (SPEMRS). The PVS on SWI was defined as a local prominence of hypointense vessels with either increased vessel number or diameter in the target area, when compared with the number or diameter of the contralateral MCA territory vessels. Six patients died and 10 survived. Although the DWI/ADC-SPEMRS and clinical profiles were similar between the nonsurvivor and survivor groups, SWI-SPEMRS was significantly lower in the nonsurvivor group (P < 0.001). The area of deoxygenation on SWI in patients with malignant MCA infarction can predict mortality. Lower SWI-SPEMRS is a potentially better predictor of poor outcome than lower DWI-SPEMRS. A larger prospective study is needed to clarify the role of SWI as a therapeutic guide in malignant MCA. PMID:26937906

  17. Amide proton transfer magnetic resonance imaging in detecting intracranial hemorrhage at different stages: a comparative study with susceptibility weighted imaging

    PubMed Central

    Ma, Xiaoyue; Bai, Yan; Lin, Yusong; Hong, Xiaohua; Liu, Taiyuan; Ma, Lun; Haacke, E Mark; Zhou, Jinyuan; Wang, Jian; Wang, Meiyun

    2017-01-01

    Amide proton transfer (APT) imaging is a noninvasive molecular magnetic resonance imaging (MRI) technique based on the chemical exchange-dependent saturation transfer mechanism. The purpose of this study was to investigate the diagnostic performance of APT MRI in detecting intracranial hemorrhage (ICH) at hyperacute, acute and subacute stages by comparing with susceptibility weighted imaging (SWI). APT MRI and SWI were performed on 33 included patients with ICH by using a 3-T MRI unit. A two-sided Mann-Whitney U test was used to detect differences in APT-weighted (APTw) and SWI signal intensities of ICH at hyperacute, acute and subacute stages. Receiver operating characteristic analysis was used to assess the diagnostic utilities of APT MRI and SWI. Our results showed that APT MRI could detect ICH at hyperacute, acute and subacute stages. Therefore, APTw signal intensity may serve as a reliable, noninvasive imaging biomarker for detecting ICH at hyperacute, acute and subacute stages. Moreover, APT MRI could provide additional information for the ICH compared with SWI. PMID:28374764

  18. 3D segmentation of annulus fibrosus and nucleus pulposus from T2-weighted magnetic resonance images.

    PubMed

    Castro-Mateos, Isaac; Pozo, Jose M; Eltes, Peter E; Rio, Luis Del; Lazary, Aron; Frangi, Alejandro F

    2014-12-21

    Computational medicine aims at employing personalised computational models in diagnosis and treatment planning. The use of such models to help physicians in finding the best treatment for low back pain (LBP) is becoming popular. One of the challenges of creating such models is to derive patient-specific anatomical and tissue models of the lumbar intervertebral discs (IVDs), as a prior step. This article presents a segmentation scheme that obtains accurate results irrespective of the degree of IVD degeneration, including pathological discs with protrusion or herniation. The segmentation algorithm, employing a novel feature selector, iteratively deforms an initial shape, which is projected into a statistical shape model space at first and then, into a B-Spline space to improve accuracy.The method was tested on a MR dataset of 59 patients suffering from LBP. The images follow a standard T2-weighted protocol in coronal and sagittal acquisitions. These two image volumes were fused in order to overcome large inter-slice spacing. The agreement between expert-delineated structures, used here as gold-standard, and our automatic segmentation was evaluated using Dice Similarity Index and surface-to-surface distances, obtaining a mean error of 0.68 mm in the annulus segmentation and 1.88 mm in the nucleus, which are the best results with respect to the image resolution in the current literature.

  19. 3D segmentation of annulus fibrosus and nucleus pulposus from T2-weighted magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Castro-Mateos, Isaac; Pozo, Jose M.; Eltes, Peter E.; Del Rio, Luis; Lazary, Aron; Frangi, Alejandro F.

    2014-12-01

    Computational medicine aims at employing personalised computational models in diagnosis and treatment planning. The use of such models to help physicians in finding the best treatment for low back pain (LBP) is becoming popular. One of the challenges of creating such models is to derive patient-specific anatomical and tissue models of the lumbar intervertebral discs (IVDs), as a prior step. This article presents a segmentation scheme that obtains accurate results irrespective of the degree of IVD degeneration, including pathological discs with protrusion or herniation. The segmentation algorithm, employing a novel feature selector, iteratively deforms an initial shape, which is projected into a statistical shape model space at first and then, into a B-Spline space to improve accuracy. The method was tested on a MR dataset of 59 patients suffering from LBP. The images follow a standard T2-weighted protocol in coronal and sagittal acquisitions. These two image volumes were fused in order to overcome large inter-slice spacing. The agreement between expert-delineated structures, used here as gold-standard, and our automatic segmentation was evaluated using Dice Similarity Index and surface-to-surface distances, obtaining a mean error of 0.68 mm in the annulus segmentation and 1.88 mm in the nucleus, which are the best results with respect to the image resolution in the current literature.

  20. [Utility of diffusion-weighted magnetic resonance imaging in severe focal traumatic brain injuries].

    PubMed

    Prieto-Valderrey, F; Muñiz-Montes, J R; López-García, J A; Villegas-Del Ojo, J; Málaga-Gil, J; Galván-García, R

    2013-01-01

    To describe the apparent diffusion coefficient (ADC) in a series of severe traumatic brain injuries, their clinical and outcome features, and possible implications. A descriptive, observational case-series study was carried out. Patients with severe traumatic brain injuries (TBIs) admitted to the ICU were subjected to MRI study using a 1.5 T scanner. Diffusion-weighted images (DWMR) were obtained using the following echo-planar pulse sequence: TR 10000 ms, TE 126.9 ms, with b values 1000 s/mm2 in the three spatial dimensions. Combining the three sets of images, an isotropic image conforming a map of the mean ADCs was obtained. DWMR was performed in 23 patients with severe TBI admitted to the ICU between 2001 and 2004. In the MR images we selected 26 regions of interest (ROIs) where ADC was recorded. We observed a clear increase in diffusion in non-treated space-occupying lesions versus other types of injuries and the normal values. A poorer outcome was recorded in patients with lower ADC values. Mean ADC in the lesions was greater than the normal values and greater in contusions than in other types of injuries, as an expression of extracellular edema. ADCs were decreased in patients with a poor outcome, suggesting an association between ischemia and the patient prognosis. Copyright © 2011 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  1. Automatic Brain Tumor Detection in T2-weighted Magnetic Resonance Images

    NASA Astrophysics Data System (ADS)

    Dvořák, P.; Kropatsch, W. G.; Bartušek, K.

    2013-10-01

    This work focuses on fully automatic detection of brain tumors. The first aim is to determine, whether the image contains a brain with a tumor, and if it does, localize it. The goal of this work is not the exact segmentation of tumors, but the localization of their approximate position. The test database contains 203 T2-weighted images of which 131 are images of healthy brain and the remaining 72 images contain brain with pathological area. The estimation, whether the image shows an afflicted brain and where a pathological area is, is done by multi resolution symmetry analysis. The first goal was tested by five-fold cross-validation technique with 100 repetitions to avoid the result dependency on sample order. This part of the proposed method reaches the true positive rate of 87.52% and the true negative rate of 93.14% for an afflicted brain detection. The evaluation of the second part of the algorithm was carried out by comparing the estimated location to the true tumor location. The detection of the tumor location reaches the rate of 95.83% of correct anomaly detection and the rate 87.5% of correct tumor location.

  2. Diffusion weighted magnetic resonance imaging in the diagnosis of parotid masses. Preliminary results

    PubMed Central

    Yologlu, Zeynel; Aydin, Hasan; Alp, Nalan A.; Aribas, Bilgin K.; Kizilgoz, Volkan; Arda, Kemal

    2016-01-01

    Objective To demonstrate the diagnostic potentials of MRI, diffusion weighted imaging (DWI), and apparent diffusion coefficient (ADC) mapping in the detection of parotid masses correlated to the histopathological results. Methods Study design was retrospective. Fifteen patients with parotid gland masses were included as the study group and contralateral normal parotis glands of same patients were taken as the control group. Patients with bilateral parotid gland tumors were excluded, 7 right-sided and 8 left-sided parotid masses were included in the research. The study took place at the Department of Radiology, Ankara, Turkey, between May 2012 and September 2014. Results Apparent diffusion coefficient measurements of 15 parotis tumors in 1000 and 750 sec/mm2 b-values with comparison to the contralateral normal gland parenchyma were demonstrated. Neurofibromas was predicted as the highest, and lipomas as the lowest ADC values. Pleomorphic adenomas, Warthin’s tumor, and normal parotid parenchyma indicate significant statistical differences from each other on the basis of mean ADC values (p<0.05). Conclusion The DWI and ADC mapping of parotis gland could aid in the differential diagnosis of benign and malignant masses. PMID:27874161

  3. Effect of weight loss on magnetic resonance imaging estimation of liver fat and volume in patients with nonalcoholic steatohepatitis.

    PubMed

    Patel, Niraj S; Doycheva, Iliana; Peterson, Michael R; Hooker, Jonathan; Kisselva, Tatiana; Schnabl, Bernd; Seki, Ekihiro; Sirlin, Claude B; Loomba, Rohit

    2015-03-01

    Little is known about how weight loss affects magnetic resonance imaging (MRI) of liver fat and volume or liver histology in patients with nonalcoholic steatohepatitis (NASH). We measured changes in liver fat and liver volume associated with weight loss by using an advanced MRI method. We analyzed data collected from a previous randomized controlled trial in which 43 adult patients with biopsy-proven NASH underwent clinical evaluation, biochemical tests, and MRI and liver biopsy analyses at the start of the study and after 24 weeks. We compared data between patients who did and did not have at least 5% decrease in body mass index (BMI) during the study period. Ten of 43 patients had at least a 5% decrease in BMI during the study period. These patients had a significant decrease in liver fat, which was based on MRI proton density fat fraction estimates (18.3% ± 7.6% to 13.6% ± 13.6%, P = .03), a relative 25.5% reduction. They also had a significant decrease in liver volume (5.3%). However, no significant changes in levels of alanine aminotransferase or aspartate aminotransferase were observed with weight loss. Thirty-three patients without at least 5% decrease in BMI had insignificant increases in estimated liver fat fraction and liver volume. A reduction in BMI of at least 5% is associated with significant decrease in liver fat and volume in patients with biopsy-proven NASH. These data should be considered in assessing effect size in studies of patients with nonalcoholic fatty liver disease or obesity that use MRI-estimated liver fat and volume as end points. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

  4. The Use of a Software-Assisted Method to Estimate Fetal Weight at and Near Term Using Magnetic Resonance Imaging.

    PubMed

    Kadji, Caroline; De Groof, Maxime; Camus, Margaux F; De Angelis, Riccardo; Fellas, Stéphanie; Klass, Magdalena; Cecotti, Vera; Dütemeyer, Vivien; Barakat, Elie; Cannie, Mieke M; Jani, Jacques C

    2017-01-01

    The aim of this study was to apply a semi-automated calculation method of fetal body volume and, thus, of magnetic resonance-estimated fetal weight (MR-EFW) prior to planned delivery and to evaluate whether the technique of measurement could be simplified while remaining accurate. MR-EFW was calculated using a semi-automated method at 38.6 weeks of gestation in 36 patients and compared to the picture archiving and communication system (PACS). Per patient, 8 sequences were acquired with a slice thickness of 4-8 mm and an intersection gap of 0, 4, 8, 12, 16, or 20 mm. The median absolute relative errors for MR-EFW and the time of planimetric measurements were calculated for all 8 sequences and for each method (assisted vs. PACS), and the difference between the methods was calculated. The median delivery weight was 3,280 g. The overall median relative error for all 288 MR-EFW calculations was 2.4% using the semi-automated method and 2.2% for the PACS method. Measurements did not differ between the 8 sequences using the assisted method (p = 0.313) or the PACS (p = 0.118), while the time of planimetric measurement decreased significantly with a larger gap (p < 0.001) and in the assisted method compared to the PACS method (p < 0.01). Our simplified MR-EFW measurement showed a dramatic decrease in time of planimetric measurement without a decrease in the accuracy of weight estimates. © 2017 S. Karger AG, Basel.

  5. A knee brace alters patella position in patellofemoral osteoarthritis: a study using weight bearing magnetic resonance imaging.

    PubMed

    Callaghan, M J; Guney, H; Reeves, N D; Bailey, D; Doslikova, K; Maganaris, C N; Hodgson, R; Felson, D T

    2016-12-01

    To assess using weight bearing magnetic resonance imaging (MRIs), whether a patellar brace altered patellar position and alignment in patellofemoral joint (PFJ) osteoarthritis (OA). Subjects age 40-70 years old with symptomatic and a radiographic Kellgren-Lawrence (K-L) evidence of PFJOA. Weight bearing knee MRIs with and without a patellar brace were obtained using an upright open 0.25 T scanner (G-Scan, Easote Biomedica, Italy). Five aspects of patellar position were measured: mediolateral alignment by the bisect offset index, angulation by patellar tilt, patellar height by patellar height ratio (patellar length/patellar tendon length), lateral patellofemoral (PF) contact area and finally a measurement of PF bony separation of the lateral patellar facet and the adjacent surface on the femoral trochlea (Fig. 1). Thirty participants were recruited (mean age 57 SD 27.8; body mass index (BMI) 27.8 SD 4.2); 17 were females. Four patients had non-usable data. Main analysis used paired t tests comparing within subject patellar position with and without brace. For bisect offset index, patellar tilt and patellar height ratio there were no significant differences between the brace and no brace conditions. However, the brace increased lateral facet contact area (P = .04) and decreased lateral PF separation (P = .03). A patellar brace alters patellar position and increases contact area between the patella and femoral trochlea. These changes would lower contact stress at the PFJ. Such changes in patella position in weight bearing provide a possible biomechanical explanation for the success of the PFJ brace in clinical trials on PFJOA. Copyright © 2016. Published by Elsevier Ltd.

  6. Distinction Between Recurrent Glioma and Radiation Injury Using Magnetic Resonance Spectroscopy in Combination With Diffusion-Weighted Imaging

    SciTech Connect

    Zeng, Q.-S. . E-mail: nanwushan@yahoo.com; Li, C.-F.; Liu Hong; Zhen, J.-H.; Feng, D.-C.

    2007-05-01

    Purpose: The aim of this study was to explore the diagnostic effectiveness of magnetic resonance (MR) spectroscopy with diffusion-weighted imaging on the evaluation of the recurrent contrast-enhancing areas at the site of treated gliomas. Methods and Materials: In 55 patients who had new contrast-enhancing lesions in the vicinity of the previously resected and irradiated high-grade gliomas, two-dimensional MR spectroscopy and diffusion-weighted imaging were performed. Spectral data for N-acetylaspartate (NAA), choline (Cho), creatine (Cr), lipid (Lip), and lactate (Lac) were analyzed in conjunction with the apparent diffusion coefficient (ADC) in all patients. Diagnosis of these lesions was assigned by means of follow-up or histopathology. Results: The Cho/NAA and Cho/Cr ratios were significantly higher in recurrent tumor than in regions of radiation injury (p < 0.01). The ADC value and ADC ratios (ADC of contrast-enhancing lesion to matching structure in the contralateral hemisphere) were significantly higher in radiation injury regions than in recurrent tumor (p < 0.01). With MR spectroscopic data, two variables (Cho/NAA and Cho/Cr ratios) were shown to differentiate recurrent glioma from radiation injury, and 85.5% of total subjects were correctly classified into groups. However, with discriminant analysis of MR spectroscopy imaging plus diffusion-weighted imaging, three variables (Cho/NAA, Cho/Cr, and ADC ratio) were identified and 96.4% of total subjects were correctly classified. There was a significant difference between the diagnostic accuracy of the two discriminant analyses (Chi-square = 3.96, p = 0.046). Conclusion: Using discriminant analysis, this study found that MR spectroscopy in combination with ADC ratio, rather than ADC value, can improve the ability to differentiate recurrent glioma and radiation injury.

  7. Determination of acute vascular injury and edema in porcine carotid arteries by T2 weighted cardiovascular magnetic resonance.

    PubMed

    Pedersen, Steen Fjord; Kim, Won Yong; Paaske, William P; Thim, Troels; Falk, Erling; Ringgaard, Steffen; Thrysøe, Samuel A

    2012-10-01

    Inflammation plays an essential role for destabilization and rupture of carotid atherosclerotic plaques causing embolic ischemic stroke. Inflammation of the vessel wall may result in the formation of edema. This study investigated whether edema in the carotid artery wall induced by acute balloon injury could be detected by cardiovascular magnetic resonance (CMR) using a T2-weighted short-tau inversion recovery sequence (T2-STIR). Edema was induced unilaterally by balloon injury in the carotid artery of six pigs. Four to nine days (average six) post injury, the carotid arteries were assessed by T2-STIR and multi-contrast weighted sequences. CMR images were matched to histopathology, validated against Evans blue, and correlated with the amount of fibrinogen in the arterial wall used as an edema marker. T2-STIR images showed that the carotid signal intensity (SI) divided by the sternocleid muscle SI of the injured carotid artery was on average 223% (P = 0.03) higher than that of the uninjured carotid artery. Using a threshold value of 4SD, T2-STIR detected edema in the vessel wall (i.e., hyperintense signal intensity) with a sensitivity of 100% and a specificity of 75%. Agreement was observed between carotid artery wall hyperintense signal intensity and Evans blue uptake (X(2) = 17.1, P < 0.001). The relative signal intensity correlated in a linear fashion with the amount of fibrinogen detected by histopathology (ρ = 0.9, P < 0.001). None of the multi-contrast weighted sequences detected edema in the carotid artery with reasonable sensitivity or specificity. T2-STIR CMR allowed carotid artery wall edema detection and may therefore be a useful non-invasive diagnostic tool for determination of inflammatory activity in the carotid artery wall.

  8. Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    1996-01-01

    AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

  9. Maximizing retention in long‐term clinical trials of a weight loss agent: use of a dietitian support team

    PubMed Central

    Riggs, M.; Klioze, S. S.; Chew, R. D.; England, R. D.; Digenio, A.

    2016-01-01

    Summary Objective High‐attrition rates have been observed in long‐term clinical trials of weight loss agents. We evaluated the impact of an innovative retention programme on 1‐year retention. Methods Three Phase 3 global multicentre clinical trials evaluated the efficacy and safety of a CB1 receptor antagonist in subjects with BMI ≥ or = 27 kg/m2. The impact of a multifaceted retention programme including a dietitian screening interview, a comprehensive culturally adapted lifestyle modification programme, and a dietitian support system to maximize lifestyle adherence, was evaluated in 4,410 subjects from four subpopulations (non‐US English‐speaking, non‐English‐speaking, US‐without dietitian screening and US‐with dietitian screening) comprising 208 centres from 15 countries. Results The median proportion retained over the first year among subjects in three protocols was 82%. Non‐English‐speaking countries showed higher retention rates (89%) compared with the USA (73%) and non‐US English‐speaking (81%) countries. Within the USA, behavioural screening was associated with 29% reduction in dropout rate; for every five monthly teleconferences attended above 11, there was a 32% decrease in dropout rate. Conclusions This novel retention programme greatly improved upon reported retention rates of studies conducted with other weight loss agents in long‐term clinical trials. Its effectiveness should be confirmed in future trials. PMID:27708842

  10. Comparative analysis of speed's impact on muscle demands during partial body weight support motor-assisted elliptical training.

    PubMed

    Burnfield, Judith M; Irons, Sonya L; Buster, Thad W; Taylor, Adam P; Hildner, Gretchen A; Shu, Yu

    2014-01-01

    Individuals with walking limitations often experience challenges engaging in functionally relevant exercise. An adapted elliptical trainer (motor to assist pedal movement, integrated body weight harness, ramps/stairs, and grab rails) has been developed to help individuals with physical disabilities and chronic conditions regain/retain walking capacity and fitness. However, limited published studies are available to guide therapeutic interventions. This repeated measures study examined the influence of motor-assisted elliptical training speed on lower extremity muscle demands at four body weight support (BWS) levels commonly used therapeutically for walking. Electromyography (EMG) and pedal trajectory data were recorded as ten individuals without known disability used the motor-assisted elliptical trainer at three speeds [20,40, 60 revolutions per minute (RPM)] during each BWS level (0%, 20%, 40%, 60%). Overall, the EMG activity (peak, mean, duration) in key stabilizer muscles (i.e., gluteus medius, gluteus maximus, vastus lateralis, medial gastrocnemius and soleus) recorded at 60 RPM exceeded those at 40 RPM, which were higher than values at 20 RPM in all but three situations (gluteus medius mean at 0% BWS, vastus lateralis mean at 20% BWS, soleus duration at 40% BWS); however, these differences did not always achieve statistical significance. Slower motor-assisted speeds can be used to accommodate weakness of gluteus medius, gluteus maximus, vastus lateralis, medial gastrocnemius and soleus. As strength improves, training at faster motor-assisted speeds may provide a means to progressively challenge key lower extremity stabilizers. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Biomechanical effects of body weight support with a novel robotic walker for over-ground gait rehabilitation.

    PubMed

    Mun, Kyung-Ryoul; Lim, Su Bin; Guo, Zhao; Yu, Haoyong

    2017-02-01

    Body weight support (BWS) promotes better functional outcomes for neurologically challenged patients. Despite the established effectiveness of BWS in gait rehabilitation, the findings on biomechanical effects of BWS training still remain contradictory. Therefore, the aim of this study is to comprehensively investigate the effects of BWS. Using a newly developed robotic walker which can facilitate pelvic motions with an active BWS unit, we compared gait parameters of ten healthy subjects during a 10-m walk with incremental levels of body weight unloading, ranging from 0 to 40 % at 10 % intervals. Significant changes in joint angles and gait temporospatial parameters were observed. In addition, the results of an EMG signal study showed that the intensity of muscle activation was significantly reduced with increasing BWS levels. The reduction was found at the ankle, knee, and hip joints in the sagittal plane as well as at the hip joint in the frontal plane. The results of this study provide an important indication of increased lateral body balance and greater stabilization in sagittal and frontal plane during gait. Our findings provide a better understanding of the biomechanical effects of BWS during gait, which will help guide the gait rehabilitation strategies.

  12. LMethyR-SVM: Predict Human Enhancers Using Low Methylated Regions based on Weighted Support Vector Machines

    PubMed Central

    Xu, Jingting; Hu, Hong; Dai, Yang

    2016-01-01

    Background The identification of enhancers is a challenging task. Various types of epigenetic information including histone modification have been utilized in the construction of enhancer prediction models based on a diverse panel of machine learning schemes. However, DNA methylation profiles generated from the whole genome bisulfite sequencing (WGBS) have not been fully explored for their potential in enhancer prediction despite the fact that low methylated regions (LMRs) have been implied to be distal active regulatory regions. Method In this work, we propose a prediction framework, LMethyR-SVM, using LMRs identified from cell-type-specific WGBS DNA methylation profiles and a weighted support vector machine learning framework. In LMethyR-SVM, the set of cell-type-specific LMRs is further divided into three sets: reliable positive, like positive and likely negative, according to their resemblance to a small set of experimentally validated enhancers in the VISTA database based on an estimated non-parametric density distribution. Then, the prediction model is obtained by solving a weighted support vector machine. Results We demonstrate the performance of LMethyR-SVM by using the WGBS DNA methylation profiles derived from the human embryonic stem cell type (H1) and the fetal lung fibroblast cell type (IMR90). The predicted enhancers are highly conserved with a reasonable validation rate based on a set of commonly used positive markers including transcription factors, p300 binding and DNase-I hypersensitive sites. In addition, we show evidence that the large fraction of the LMethyR-SVM predicted enhancers are not predicted by ChromHMM in H1 cell type and they are more enriched for the FANTOM5 enhancers. Conclusion Our work suggests that low methylated regions detected from the WGBS data are useful as complementary resources to histone modification marks in developing models for the prediction of cell-type-specific enhancers. PMID:27662487

  13. Weight-supported training of the upper extremity in children with cerebral palsy: a motor learning study.

    PubMed

    Keller, Jeffrey W; van Hedel, Hubertus J A

    2017-08-30

    Novel neurorehabilitation technologies build upon treatment principles derived from motor learning studies. However, few studies have investigated motor learning with assistive devices in children and adolescents with Cerebral Palsy (CP). The aim of this study was to investigate whether children with CP who trained with weight support in a playful, virtual environment would improve upper extremity task performance (i.e. skill acquisition), transfer, and retention, three aspects that indicate whether motor learning might have occurred or not. Eleven children with CP (mean age 13.3 years, standard deviation 3.4 years), who were mildly to moderately impaired, participated. They played in the Armeo® Spring the exergame Moorhuhn with their more affected arm during 3 days (70 min pure play time). For this within-subject design, kinematic assessments, the Box and Block Test, and five items of the Melbourne Assessment were administered twice during a baseline week (one week before the intervention), directly before and after the intervention, and one day after the training phase (retention). The average exergame score improved from 209.55 to 339.73 (p < 0.001, Cohen's d = 1.80), indicating skill acquisition. The change in the Box and Block test improved from 0.45 (baseline week) to 3.95 (intervention week; p = 0.008, d = 1.59) indicating skill transfer. The kinematic assessments and the Melbourne items did not change. Improvement in game score and Box and Bock Test persisted one day later (retention). We found evidence indicating the successful acquisition, transfer, and retention of upper extremity skills in children with CP. We therefore infer that motor learning occurred when children with CP trained their more affected arm with weight-support in a playful, virtual environment.

  14. Randomised controlled feasibility trial of a web-based weight management intervention with nurse support for obese patients in primary care

    PubMed Central

    2014-01-01

    Background There is a need for cost-effective weight management interventions that primary care can deliver to reduce the morbidity caused by obesity. Automated web-based interventions might provide a solution, but evidence suggests that they may be ineffective without additional human support. The main aim of this study was to carry out a feasibility trial of a web-based weight management intervention in primary care, comparing different levels of nurse support, to determine the optimal combination of web-based and personal support to be tested in a full trial. Methods This was an individually randomised four arm parallel non-blinded trial, recruiting obese patients in primary care. Following online registration, patients were randomly allocated by the automated intervention to either usual care, the web-based intervention only, or the web-based intervention with either basic nurse support (3 sessions in 3 months) or regular nurse support (7 sessions in 6 months). The main outcome measure (intended as the primary outcome for the main trial) was weight loss in kg at 12 months. As this was a feasibility trial no statistical analyses were carried out, but we present means, confidence intervals and effect sizes for weight loss in each group, uptake and retention, and completion of intervention components and outcome measures. Results All randomised patients were included in the weight loss analyses (using Last Observation Carried Forward). At 12 months mean weight loss was: usual care group (n = 43) 2.44 kg; web-based only group (n = 45) 2.30 kg; basic nurse support group (n = 44) 4.31 kg; regular nurse support group (n = 47) 2.50 kg. Intervention effect sizes compared with usual care were: d = 0.01 web-based; d = 0.34 basic nurse support; d = 0.02 regular nurse support. Two practices deviated from protocol by providing considerable weight management support to their usual care patients. Conclusions This study demonstrated the

  15. Randomised controlled feasibility trial of a web-based weight management intervention with nurse support for obese patients in primary care.

    PubMed

    Yardley, Lucy; Ware, Lisa J; Smith, Emily R; Williams, Sarah; Bradbury, Katherine J; Arden-Close, Emily J; Mullee, Mark A; Moore, Michael V; Peacock, Janet L; Lean, Mike E J; Margetts, Barrie M; Byrne, Chris D; Hobbs, Richard F D; Little, Paul

    2014-05-21

    There is a need for cost-effective weight management interventions that primary care can deliver to reduce the morbidity caused by obesity. Automated web-based interventions might provide a solution, but evidence suggests that they may be ineffective without additional human support. The main aim of this study was to carry out a feasibility trial of a web-based weight management intervention in primary care, comparing different levels of nurse support, to determine the optimal combination of web-based and personal support to be tested in a full trial. This was an individually randomised four arm parallel non-blinded trial, recruiting obese patients in primary care. Following online registration, patients were randomly allocated by the automated intervention to either usual care, the web-based intervention only, or the web-based intervention with either basic nurse support (3 sessions in 3 months) or regular nurse support (7 sessions in 6 months). The main outcome measure (intended as the primary outcome for the main trial) was weight loss in kg at 12 months. As this was a feasibility trial no statistical analyses were carried out, but we present means, confidence intervals and effect sizes for weight loss in each group, uptake and retention, and completion of intervention components and outcome measures. All randomised patients were included in the weight loss analyses (using Last Observation Carried Forward). At 12 months mean weight loss was: usual care group (n = 43) 2.44 kg; web-based only group (n = 45) 2.30 kg; basic nurse support group (n = 44) 4.31 kg; regular nurse support group (n = 47) 2.50 kg. Intervention effect sizes compared with usual care were: d = 0.01 web-based; d = 0.34 basic nurse support; d = 0.02 regular nurse support. Two practices deviated from protocol by providing considerable weight management support to their usual care patients. This study demonstrated the feasibility of delivering a web-based weight

  16. Evaluation of the pituitary gland using magnetic resonance imaging: T1-weighted vs. VIBE imaging.

    PubMed

    Davis, M A; Castillo, M

    2013-06-01

    Volumetric interpolated breath-hold examination (VIBE) is used for abdominal imaging as a fast and efficient modality. Evaluation of brain lesions using VIBE is not common and its use for the pituitary gland has not yet been addressed. Our goal was to compare coronal T1-weighted (T1W) and VIBE images in patients undergoing studies of the pituitary gland. We hypothesized that, for this purpose, VIBE is superior to T1W images. T1W and VIBE images of the pituitary gland in 32 patients were evaluated. The two sequences were compared with specific attention to: contrast enhancement (gland and cavernous sinuses) and ability to view the anatomy of the cavernous sinuses. In patients with macroadenomas, visualization of the optic chiasm was also assessed. Images were rated as: VIBE being better, equal, or worse in comparison to T1W images. We also compared VIBE and T1W images specifically looking at micro/macro-adenomas and post-surgical patients. Statistical analysis was performed using chi-square statistics. Of the 32 patients, the VIBE sequence showed superior contrast enhancement in 18 patients, six were found as being equal to T1W, and in eight instances VIBE was found to be worse than T1W. These results were statistically significant (p=.02). When looking at micro/macro-adenomas and post-surgical patients specifically, there was a trend to VIBE being superior to T1W but these data were not statistically significant. Visualization of chiasm in macroadenomas was similar for both techniques. VIBE was significantly superior to T1W with respect to pituitary and cavernous sinus contrast enhancement and cavernous sinus anatomy. A trend towards VIBE being superior in the evaluation of adenomas (pre- and post-operative) was seen, but it was not statistically significant. This is likely due to the small population size.

  17. A miniaturized two-DOF rotational gyro with a ball-joint supported permanent magnet rotor

    NASA Astrophysics Data System (ADS)

    Li, Hai; Liu, Xiaowei; Chen, Weiping; Zhang, Haifeng

    2016-07-01

    We proposed a miniaturized two-degrees of freedom (DOF) rotational gyro with a ball-joint supported permanent magnet rotor. The structural design and the dynamic model of the gyro are presented and analyzed in detail in this paper and testified by preliminary experiments. When the rotor tilts away from its null position, it will be constrained by a contactless magnetic equivalent elastic torque derived from the driving structure. As a rotational gyro, this structure is very simple and small, with a core size less than 6 cm3, and it needs only 0.75 W to keep the rotor spinning at a speed of 15 000 revolutions per minute (rpm) in a standard air pressure condition. Preliminary measurements show that, at 7000 rpm within a full scale of ±100 °/s, the gyro has a scale factor of 18.69 mV/(°/s), and a nonlinearity of 0.33% is also achieved through calculation. The results show that the gyro can be used to measure two DOFs' angular rates of carriers without close-loop control due to the existence of magnetic equivalent elasticity.

  18. Covalent organic framework-coated magnetic graphene as a novel support for trypsin immobilization.

    PubMed

    Wang, Heping; Jiao, Fenglong; Gao, Fangyuan; Zhao, Xinyuan; Zhao, Yan; Shen, Yehua; Zhang, Yangjun; Qian, Xiaohong

    2017-03-01

    Deep and efficient proteolysis is the critical premise in mass spectrometry-based bottom-up proteomics. It is difficult for traditional in-solution digestion to meet the requirement unless prolonged digestion time and enhanced enzyme dosage are employed, which makes the whole workflow time-consuming and costly. The abovementioned problems could be effectively ameliorated by anchoring many proteases on solid supports. In this work, covalent organic framework-coated magnetic graphene (MG@TpPa-1) was designed and prepared as a novel enzyme carrier for the covalent immobilization of trypsin with a high degree of loading (up to 268 μg mg(-1)). Profiting from the advantages of magnetic graphene and covalent organic frameworks, the novel trypsin bioreactor was successfully applied for the enzymatic digestion of a model protein with dramatically improved digestion efficiency, stability, and reusability. Complete digestion could be achieved in a time period as short as 2 min. For the digestion of proteins extracted from Amygdalus pedunculata, a total of 2833 protein groups were identified, which was slightly more than those obtained by 12 h of in-solution digestion (2739 protein groups). All of the results demonstrate that MG@TpPa-1-trypsin is an excellent candidate for sample preparation in a high-throughput proteomics analysis. Graphical abstract Covalent organic frameworks-coated magnetic graphene was prepared as novel carrier for highly efficient tryptic immobilization.

  19. Mobile magnetic particles as solid-supports for rapid surface-based bioanalysis in continuous flow.

    PubMed

    Peyman, Sally A; Iles, Alexander; Pamme, Nicole

    2009-11-07

    An extremely versatile microfluidic device is demonstrated in which multi-step (bio)chemical procedures can be performed in continuous flow. The system operates by generating several co-laminar flow streams, which contain reagents for specific (bio)reactions across a rectangular reaction chamber. Functionalized magnetic microparticles are employed as mobile solid-supports and are pulled from one side of the reaction chamber to the other by use of an external magnetic field. As the particles traverse the co-laminar reagent streams, binding and washing steps are performed on their surface in one operation in continuous flow. The applicability of the platform was first demonstrated by performing a proof-of-principle binding assay between streptavidin coated magnetic particles and biotin in free solution with a limit of detection of 20 ng mL(-1) of free biotin. The system was then applied to a mouse IgG sandwich immunoassay as a first example of a process involving two binding steps and two washing steps, all performed within 60 s, a fraction of the time required for conventional testing.

  20. Multi-objective optimization design of a high-speed PM machine supported by magnetic bearings

    NASA Astrophysics Data System (ADS)

    Han, Bangcheng; Xue, Qinghao; Liu, Xu; Wang, Kun

    2017-08-01

    This paper proposes an optimal design method of permanent magnet machine (PMM) with cylindrical permanent magnet supported by magnetic bearings. The objectives of optimization design are minimizing the rotor loss while maximizing the power density of the PMM as well as the 1st order nature frequency of the rotor, and the constraints are size, the strength safety factor and the phase current. A 30 kW, 48,000 r/min PMM designed by the multi-objective optimization method is proposed and the results indicate: the rotor loss is decreased from 393 W to 290 W (is reduced by 26.2%); the power density of the PMM is increased from 1.86 kW/kg to 2.19 kW/kg (is increased by 17.7%); the 1st order nature frequency of the rotor is increased from 1579 Hz to 1812 Hz (is increased by 14.7%). The performances of the PMM are improved after optimization, which are verified by experiment.

  1. The relative importance of body change strategies, weight perception, perceived social support, and self-esteem on adolescent depressive symptoms: longitudinal findings from a national sample.

    PubMed

    Rawana, Jennine S

    2013-07-01

    This study aimed to evaluate the relative importance of body change strategies and weight perception in adolescent depression after accounting for established risk factors for depression, namely low social support across key adolescent contexts. The moderating effect of self-esteem was also examined. Participants (N=4587, 49% female) were selected from the National Longitudinal Study of Adolescent Health. Regression analyses were conducted on the association between well-known depression risk factors (lack of perceived support from parents, peers, and schools), body change strategies, weight perception, and adolescent depressive symptoms one year later. Each well-known risk factor significantly predicted depressive symptoms. Body change strategies related to losing weight and overweight perceptions predicted depressive symptoms above and beyond established risk factors. Self-esteem moderated the relationship between trying to lose weight and depressive symptoms. Maladaptive weight loss strategies and overweight perceptions should be addressed in early identification depression programs. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Magnetic Resonance Imaging of Changes in Abdominal Compartments in Obese Diabetics during a Low-Calorie Weight-Loss Program

    PubMed Central

    Vogt, Lena J.; Steveling, Antje; Meffert, Peter J.; Kromrey, Marie-Luise; Kessler, Rebecca; Hosten, Norbert; Krüger, Janine; Gärtner, Simone; Aghdassi, Ali A.; Mayerle, Julia; Lerch, Markus M.; Kühn, Jens-Peter

    2016-01-01

    Objectives To investigate changes in the fat content of abdominal compartments and muscle area during weight loss using confounder-adjusted chemical-shift-encoded magnetic resonance imaging (MRI) in overweight diabetics. Methods Twenty-nine obese diabetics (10/19 men/women, median age: 59.0 years, median body mass index (BMI): 34.0 kg/m2) prospectively joined a standardized 15-week weight-loss program (six weeks of formula diet exclusively, followed by reintroduction of regular food with gradually increasing energy content over nine weeks) over 15 weeks. All subjects underwent a standardized MRI protocol including a confounder-adjusted chemical-shift-encoded MR sequence with water/fat separation before the program as well at the end of the six weeks of formula diet and at the end of the program at 15 weeks. Fat fractions of abdominal organs and vertebral bone marrow as well as volumes of visceral and subcutaneous fat were determined. Furthermore, muscle area was evaluated using the L4/L5 method. Data were compared using the Wilcoxon signed-rank test for paired samples. Results Median BMI decreased significantly from 34.0 kg/m2 to 29.9 kg/m2 (p < 0.001) at 15 weeks. Liver fat content was normalized (14.2% to 4.1%, p < 0.001) and vertebral bone marrow fat (57.5% to 53.6%, p = 0.018) decreased significantly throughout the program, while fat content of pancreas (9.0%), spleen (0.0%), and psoas muscle (0.0%) did not (p > 0.15). Visceral fat volume (3.2 L to 1.6 L, p < 0.001) and subcutaneous fat diameter (3.0 cm to 2.2 cm, p < 0.001) also decreased significantly. Muscle area declined by 6.8% from 243.9 cm2 to 226.8 cm2. Conclusion MRI allows noninvasive monitoring of changes in abdominal compartments during weight loss. In overweight diabetics, weight loss leads to fat reduction in abdominal compartments, such as visceral fat, as well as liver fat and vertebral bone marrow fat while pancreas fat remains unchanged. PMID:27110719

  3. HSX: Engineering Design and Fabrication of the main Magnet Coils, Vacuum Vessel and Support/Alignment Structure

    NASA Astrophysics Data System (ADS)

    Anderson, F. Simon B.; Anderson, D. T.; Almagri, A. F.; Matthews, P. G.; Probert, P. H.; Shohet, J. L.; Talmadge, J. N.

    1996-11-01

    The HSX device, with a magnetic field consisting of a SINGLE dominant HELICAL component, has a set of 48 twisted main magnetic field coils. Engineering analysis (ANSYS) has resulted in a set of construction and alignment constraints and goals for field accuracy and coil structural strength. Close proximity of the main coil set to the magnetic separatrix imposes space restrictions on the vacuum vessel. Fabrication of the vessel using explosive techniques, and the structural analysis for the stresses in the vacuum chamber will be discussed. Crucial to the integrity of the quasihelical magnetic field is the accurate positioning of the magnet coils and maintenance of the position during operation. The design and construct- ion of the completed support structure for HSX coils will also be presented. *** Work supported by U.S Dept. of Energy Grant DE-FG02-93ER54222

  4. Treadmill Training in Multiple Sclerosis: Can Body Weight Support or Robot Assistance Provide Added Value? A Systematic Review

    PubMed Central

    Swinnen, Eva; Beckwée, David; Pinte, Droesja; Meeusen, Romain; Baeyens, Jean-Pierre; Kerckhofs, Eric

    2012-01-01

    Purpose. This systematic review critically analyzes the literature on the effectiveness of treadmill training (TT), body-weight-supported TT (BWSTT), and robot-assisted TT (RATT) in persons with multiple sclerosis (MS), with focus on gait-related outcome measurements. Method. Electronic databases (Pubmed, Pedro, Web of Science, and Cochrane Library) and reference lists of articles and narrative reviews were searched. Pre-, quasi- and true-experimental studies were included if adult persons with MS were involved in TT, BWSTT, or RATT intervention studies published before 2012. Descriptive analysis was performed and two researchers scored the methodological quality of the studies. Results. 5 true- and 3 preexperimental studies (mean quality score: 66%) have been included. In total 161 persons with MS were involved (TT, BWSTT, or RATT, 6–42 sessions; 2–5x/week; 3–21 weeks). Significant improvements in walking speed and endurance were reported. Furthermore, improvements of step length, double-support time, and Expanded Disability Status Scale were found. Conclusions. There is a limited number of published papers related to TT in persons with MS, concluding that TT, BWSTT, and RATT improve the walking speed and endurance. However, it is not clear what type of TT is most effective. RCTs with larger but more homogeneous populations are needed. PMID:22701177

  5. Gait rehabilitation with body weight-supported treadmill training for a blast injury survivor with traumatic brain injury.

    PubMed

    Scherer, Matthew

    2007-01-01

    Research supports the use of body weight-supported treadmill training (BWSTT) in patients with hemi-paresis and may show promise as a gait training and neuromuscular re-education intervention in the blast-injured, traumatic brain injury (TBI) population. The purpose of this case study is to document the use BWSTT and goal-directed therapy in the improvement of gait quality, gait speed and maximum distance ambulated in a blast injury survivor with TBI. A 36-year-old male soldier injured by a rocket propelled grenade in Iraq who began physical therapy and gait training incorporating purposeful postural stability and mobility interventions as well as BWSTT. Missouri Assisted Gait scores, six-minute walk distances, and maximum distance ambulated all increased post gait training with BWSTT as a component to PT intervention. Intensive gait training including BWSTT may have some efficacy in managing significant blast trauma patients with TBI however, further research is necessary to establish efficacy and appropriateness in this patient population.

  6. Parental support for policy actions to reduce weight stigma toward youth in schools and children's television programs: trends from 2011 to 2013.

    PubMed

    Suh, Young; Puhl, Rebecca; Liu, Sai; Fleming Milici, Frances

    2014-12-01

    Despite the pervasiveness and negative physical and psychosocial implications of weight-based victimization (WBV) in youth, antibullying polices in schools rarely address this issue. Additionally, children's media perpetuates weight stigma, but regulation of stigmatizing media content is nonexistent. In 2011-2013, a diverse national sample of 2185 parents (n=716 in 2011, 755 in 2012, and 714 in 2013) was analyzed to evaluate parental support for four proposed policies across the 3 years. Actions addressed (1) strengthening policies to reduce weight stigma, (2) media portrayals of children with diverse body sizes, (3) media portrayals of such children engaged in healthy behaviors, and (4) antibullying policies in schools. Chi-square tests with Bonferroni's corrections and multiple logistic regression analyses were conducted. Across time, support for policies to address weight stigma remained consistent or increased, primarily in 2012-2013. At least 86% of participants consistently favored implementing antibullying policies in schools. Parents became increasingly supportive of policies regulating television content to positively portray children of diverse body sizes and show such children engaged in health behaviors, as well as establishing weight-related antibullying policies. Specific predictors of support included gender, race, and political affiliation. There is a consistent and high level of parental support for weight stigma-related policies, particularly for antibullying policies. Findings can inform development of policies to rectify health and social disparities faced by overweight and obese youth.

  7. Managing magnetic resonance imaging machines: support tools for scheduling and planning.

    PubMed

    Carpenter, Adam P; Leemis, Lawrence M; Papir, Alan S; Phillips, David J; Phillips, Grace S

    2011-06-01

    We devise models and algorithms to estimate the impact of current and future patient demand for examinations on Magnetic Resonance Imaging (MRI) machines at a hospital radiology department. Our work helps improve scheduling decisions and supports MRI machine personnel and equipment planning decisions. Of particular novelty is our use of scheduling algorithms to compute the competing objectives of maximizing examination throughput and patient-magnet utilization. Using our algorithms retrospectively can help (1) assess prior scheduling decisions, (2) identify potential areas of efficiency improvement and (3) identify difficult examination types. Using a year of patient data and several years of MRI utilization data, we construct a simulation model to forecast MRI machine demand under a variety of scenarios. Under our predicted demand model, the throughput calculated by our algorithms acts as an estimate of the overtime MRI time required, and thus, can be used to help predict the impact of different trends in examination demand and to support MRI machine staffing and equipment planning.

  8. Sensorimotor Plasticity after Music-Supported Therapy in Chronic Stroke Patients Revealed by Transcranial Magnetic Stimulation

    PubMed Central

    Amengual, Julià L.; Rojo, Nuria; Veciana de las Heras, Misericordia; Marco-Pallarés, Josep; Grau-Sánchez, Jennifer; Schneider, Sabine; Vaquero, Lucía; Juncadella, Montserrat; Montero, Jordi; Mohammadi, Bahram; Rubio, Francisco; Rueda, Nohora; Duarte, Esther; Grau, Carles; Altenmüller, Eckart; Münte, Thomas F.; Rodríguez-Fornells, Antoni

    2013-01-01

    Background Several recently developed therapies targeting motor disabilities in stroke sufferers have shown to be more effective than standard neurorehabilitation approaches. In this context, several basic studies demonstrated that music training produces rapid neuroplastic changes in motor-related brain areas. Music-supported therapy has been recently developed as a new motor rehabilitation intervention. Methods and Results In order to explore the plasticity effects of music-supported therapy, this therapeutic intervention was applied to twenty chronic stroke patients. Before and after the music-supported therapy, transcranial magnetic stimulation was applied for the assessment of excitability changes in the motor cortex and a 3D movement analyzer was used for the assessment of motor performance parameters such as velocity, acceleration and smoothness in a set of diadochokinetic movement tasks. Our results suggest that the music-supported therapy produces changes in cortical plasticity leading the improvement of the subjects' motor performance. Conclusion Our findings represent the first evidence of the neurophysiological changes induced by this therapy in chronic stroke patients, and their link with the amelioration of motor performance. Further studies are needed to confirm our observations. PMID:23613966

  9. Effects of Progressive Body Weight Support Treadmill Forward and Backward Walking Training on Stroke Patients’ Affected Side Lower Extremity’s Walking Ability

    PubMed Central

    Kim, Kyunghoon; Lee, Sukmin; Lee, Kyoungbo

    2014-01-01

    [Purpose] The purpose of the present study was to examine the effects of progressive body weight supported treadmill forward and backward walking training (PBWSTFBWT), progressive body weight supported treadmill forward walking training (PBWSTFWT), progressive body weight supported treadmill backward walking training (PBWSTBWT), on stroke patients’ affected side lower extremity’s walking ability. [Subjects and Methods] A total of 36 chronic stroke patients were divided into three groups with 12 subjects in each group. Each of the groups performed one of the progressive body weight supported treadmill training methods for 30 minute, six times per week for three weeks, and then received general physical therapy without any other intervention until the follow-up tests. For the assessment of the affected side lower extremity’s walking ability, step length of the affected side, stance phase of the affected side, swing phase of the affected side, single support of the affected side, and step time of the affected side were measured using optogait and the symmetry index. [Results] In the within group comparisons, all the three groups showed significant differences between before and after the intervention and in the comparison of the three groups, the PBWSTFBWT group showed more significant differences in all of the assessed items than the other two groups. [Conclusion] In the present study progressive body weight supported treadmill training was performed in an environment in which the subjects were actually walked, and PBWSTFBWT was more effective at efficiently training stroke patients’ affected side lower extremity’s walking ability. PMID:25540499

  10. Molecular weight dependence of the intrinsic size effect on Tg in AAO template-supported polymer nanorods: A DSC study

    NASA Astrophysics Data System (ADS)

    Askar, Shadid; Wei, Tong; Tan, Anthony W.; Torkelson, John M.

    2017-05-01

    Many studies have established a major effect of nanoscale confinement on the glass transition temperature (Tg) of polystyrene (PS), most commonly in thin films with one or two free surfaces. Here, we characterize smaller yet significant intrinsic size effects (in the absence of free surfaces or significant attractive polymer-substrate interactions) on the Tg and fragility of PS. Melt infiltration of various molecular weights (MWs) of PS into anodic aluminum oxide (AAO) templates is used to create nanorods supported on AAO with rod diameter (d) ranging from 24 to 210 nm. The Tg (both as Tg,onset and fictive temperature) and fragility values are characterized by differential scanning calorimetry. No intrinsic size effect is observed for 30 kg/mol PS in template-supported nanorods with d = 24 nm. However, effects on Tg are present for PS nanorods with Mn and Mw ≥ ˜175 kg/mol, with effects increasing in magnitude with increasing MW. For example, in 24-nm-diameter template-supported nanorods, Tg, rod - Tg, bulk = -2.0 to -2.5 °C for PS with Mn = 175 kg/mol and Mw = 182 kg/mol, and Tg, rod - Tg, bulk = ˜-8 °C for PS with Mn = 929 kg/mol and Mw = 1420 kg/mol. In general, reductions in Tg occur when d ≤ ˜2Rg, where Rg is the bulk polymer radius of gyration. Thus, intrinsic size effects are significant when the rod diameter is smaller than the diameter (2Rg) associated with the spherical volume pervaded by coils in bulk. We hypothesize that the Tg reduction occurs when chain segment packing frustration is sufficiently perturbed by confinement in the nanorods. This explanation is supported by observed reductions in fragility with the increasing extent of confinement. We also explain why these small intrinsic size effects do not contradict reports that the Tg-confinement effect in supported PS films with one free surface exhibits little or no MW dependence.

  11. Molecular weight dependence of the intrinsic size effect on Tg in AAO template-supported polymer nanorods: A DSC study.

    PubMed

    Askar, Shadid; Wei, Tong; Tan, Anthony W; Torkelson, John M

    2017-05-28

    Many studies have established a major effect of nanoscale confinement on the glass transition temperature (Tg) of polystyrene (PS), most commonly in thin films with one or two free surfaces. Here, we characterize smaller yet significant intrinsic size effects (in the absence of free surfaces or significant attractive polymer-substrate interactions) on the Tg and fragility of PS. Melt infiltration of various molecular weights (MWs) of PS into anodic aluminum oxide (AAO) templates is used to create nanorods supported on AAO with rod diameter (d) ranging from 24 to 210 nm. The Tg (both as Tg,onset and fictive temperature) and fragility values are characterized by differential scanning calorimetry. No intrinsic size effect is observed for 30 kg/mol PS in template-supported nanorods with d = 24 nm. However, effects on Tg are present for PS nanorods with Mn and Mw ≥ ∼175 kg/mol, with effects increasing in magnitude with increasing MW. For example, in 24-nm-diameter template-supported nanorods, Tg, rod - Tg, bulk = -2.0 to -2.5 °C for PS with Mn = 175 kg/mol and Mw = 182 kg/mol, and Tg, rod - Tg, bulk = ∼-8 °C for PS with Mn = 929 kg/mol and Mw = 1420 kg/mol. In general, reductions in Tg occur when d ≤ ∼2Rg, where Rg is the bulk polymer radius of gyration. Thus, intrinsic size effects are significant when the rod diameter is smaller than the diameter (2Rg) associated with the spherical volume pervaded by coils in bulk. We hypothesize that the Tg reduction occurs when chain segment packing frustration is sufficiently perturbed by confinement in the nanorods. This explanation is supported by observed reductions in fragility with the increasing extent of confinement. We also explain why these small intrinsic size effects do not contradict reports that the Tg-confinement effect in supported PS films with one free surface exhibits little or no MW dependence.

  12. Prediction of outcome in new-born infants with arterial ischaemic stroke using diffusion-weighted magnetic resonance imaging.

    PubMed

    De Vries, L S; Van der Grond, J; Van Haastert, I C; Groenendaal, F

    2005-02-01

    The aim of this study was to assess the additional value of diffusion-weighted magnetic resonance imaging (DW-MRI) compared to conventional magnetic resonance imaging (MRI) in new-born infants with arterial ischaemic stroke, with regard to the prediction of neurodevelopmental outcome. Neonatal DW-MRI data were available in 15 infants with a gestational age of > or = 35 weeks and repeat MRI data were obtained in 12 of the 14 survivors. T(1)- and T(2)-weighted transverse images were obtained as well as 4-mm DWI slices. ADC maps were calculated in manually selected regions on the basis of the DWI scans. All 14 survivors were seen in the follow-up clinic and 12 were > 18 months when last seen. T (2) hyperintensity was detected in the descending white matter tracts at the level of the internal capsule in 7 infants and in only one of these also at the level of the cerebral peduncles. Increased signal intensity (SI) was seen on DW-MRI in 8 infants in the descending white matter tract ipsilateral to the territorial infarct at the level of the internal capsule and in 5 of these also at the level of the cerebral peduncles. ADC maps were available in 12 infants. ADC values were calculated at the level of the cerebral peduncles, using the contralateral side as a reference value. A significantly reduced value was found in 3 of the 5 infants who showed an increased SI on DW-MRI. ADC maps were not available in the other two. Five of the seven infants with abnormalities on DW-MRI/ADC of the corticospinal tracts developed a mild to moderate hemiplegia, one showed an asymmetry of tone and one with only involvement of the anterior part of the internal capsule was normal at follow-up. Wallerian degeneration, seen at the level of the cerebral peduncles and/or the PLIC on the repeat MRI, was seen in the 5 infants who had shown acute changes of the corticospinal tracts in the neonatal period and who went on to develop motor sequelae. Compared to MRI, DW-MRI and ADC maps provided

  13. Differential Diagnosis of Benign and Malignant Breast Tumors Using Apparent Diffusion Coefficient Value Measured Through Diffusion-Weighted Magnetic Resonance Imaging.

    PubMed

    Qu, Rong-Feng; Guo, Dong-Rui; Chang, Zhe-Xing; Meng, Jie; Sun, Yan; Hao, Shu-Hong; Shi, Guang; Sun, Jian

    2015-01-01

    Apparent diffusion coefficient (ADC) value measurement of nodes in diffusion-weighted imaging was widely used in differentiating different types of human tumors. The aim of this meta-analysis was to evaluate the clinical value of ADC measurement through diffusion-weighted magnetic resonance imaging (DW-MRI) in the differential diagnosis of benign and malignant breast tumors. Relevant studies were identified through computer-based search of databases, which were supplemented through manual search strategies. Case-control studies were selected in adherence with our strict inclusion and exclusion criteria. Statistical analysis was conducted using Stata 12.0 statistical software (StataCorp, College Station, Tex). Our database searches initially retrieved 602 studies (320 studies in Chinese and 282 studies in English), and 31 studies (18 studies in English and 13 studies in Chinese) were eventually selected for meta-analysis. These 31 case-control studies included a total of 926 normal breast tissues and 2323 breast tumors (911 benign tumors and 1412 malignant tumors). Our meta-analysis showed that ADC values measured through DW-MRI were higher in benign breast tumors compared with malignant breast tumors, and this difference was statistically significant. In addition, the ADC values in the normal breast tissues were markedly higher than the benign breast tumors, which were also at a statistically significant level. Consistent with these observations, the ADC values in the normal breast tissues were significantly higher when compared with the values found in the malignant breast tumors. Our data strongly support the conclusion that the ADC value measured through DW-MRI is an important radiographic index for differential diagnosis of benign and malignant breast tumors and is critical to our assessment of the internal structure of tumors.

  14. Perianal Fistula With and Without Abscess: Assessment of Fistula Activity Using Diffusion-Weighted Magnetic Resonance Imaging.

    PubMed

    Bakan, Selim; Olgun, Deniz Cebi; Kandemirli, Sedat Giray; Tutar, Onur; Samanci, Cesur; Dikici, Suleyman; Simsek, Osman; Rafiee, Babak; Adaletli, Ibrahim; Mihmanli, Ismail

    2015-10-01

    Magnetic resonance imaging (MRI) is highly accurate for the depiction of both the primary tract of fistula and abscesses, in patients with perianal disease. In addition, MRI can be used to evaluate the activity of fistulas, which is a significant factor for determining the therapeutic strategy. This study aimed to determine the usefulness of diffusion-weighted (DW) MRI for assessing activity and visibility of perianal fistula. Fifty-three patients with 56 perianal fistulas were included in the current retrospective study. The T2-weighted imaging (T2WI) and DWMRI were performed and apparent diffusion coefficient (ADC) values of fistulas were measured. Fistulas were classified into two groups: only perianal fistulas and fistulas accompanied by abscess. Fistulas were also classified into two groups, based on clinical findings: positive inflammatory activity (PIA) and negative inflammatory activity (NIA). Mean ADC value (mm(2)/s) of PIA group was significantly lower than that of NIA group, regarding lesions in patients with abscess-associated fistulas (1.371 × 10(-3) ± 0.168 × 10(-3) vs. 1.586 × 10(-3) ± 0.136 × 10(-3); P = 0.036). No statistically significant difference was found in mean ADC values between PIA and NIA groups, in patients with only perianal fistulas (P = 0.507). Perianal fistula visibility was greater with combined evaluation of T2WI and DWMRI than with T2WI, for two reviewers (P = 0.046 and P = 0.014). The DWMRI is a useful technique for evaluating activity of fistulas with abscess. Perianal fistula visibility is greater with combined T2WI and DWMRI than T2WI alone.

  15. Spontaneous Development of Full Weight-Supported Stepping after Complete Spinal Cord Transection in the Neonatal Opossum, Monodelphis domestica

    PubMed Central

    Wheaton, Benjamin J.; Callaway, Jennifer K.; Ek, C. Joakim; Dziegielewska, Katarzyna M.; Saunders, Norman R.

    2011-01-01

    Spinal cord trauma in the adult nervous system usually results in permanent loss of function below the injury level. The immature spinal cord has greater capacity for repair and can develop considerable functionality by adulthood. This study used the marsupial laboratory opossum Monodelphis domestica, which is born at a very early stage of neural development. Complete spinal cord transection was made in the lower-thoracic region of pups at postnatal-day 7 (P7) or P28, and the animals grew to adulthood. Injury at P7 resulted in a dense neuronal tissue bridge that connected the two ends of the cord; retrograde neuronal labelling indicated that supraspinal and propriospinal innervation spanned the injury site. This repair was associated with pronounced behavioural recovery, coordinated gait and an ability to use hindlimbs when swimming. Injury at P28 resulted in a cyst-like cavity encased in scar tissue forming at the injury site. Using retrograde labelling, no labelled brainstem or propriospinal neurons were found above the lesion, indicating that detectable neuronal connectivity had not spanned the injury site. However, these animals could use their hindlimbs to take weight-supporting steps but could not use their hindlimbs when swimming. White matter, demonstrated by Luxol Fast Blue staining, was present in the injury site of P7- but not P28-injured animals. Overall, these studies demonstrated that provided spinal injury occurs early in development, regrowth of supraspinal innervation is possible. This repair appears to lead to improved functional outcomes. At older ages, even without detectable axonal growth spanning the injury site, substantial development of locomotion was still possible. This outcome is discussed in conjunction with preliminary findings of differences in the local propriospinal circuits following spinal cord injury (demonstrated with fluororuby labelling), which may underlie the weight bearing locomotion observed in the apparent absence of

  16. Spontaneous development of full weight-supported stepping after complete spinal cord transection in the neonatal opossum, Monodelphis domestica.

    PubMed

    Wheaton, Benjamin J; Callaway, Jennifer K; Ek, C Joakim; Dziegielewska, Katarzyna M; Saunders, Norman R

    2011-01-01

    Spinal cord trauma in the adult nervous system usually results in permanent loss of function below the injury level. The immature spinal cord has greater capacity for repair and can develop considerable functionality by adulthood. This study used the marsupial laboratory opossum Monodelphis domestica, which is born at a very early stage of neural development. Complete spinal cord transection was made in the lower-thoracic region of pups at postnatal-day 7 (P7) or P28, and the animals grew to adulthood. Injury at P7 resulted in a dense neuronal tissue bridge that connected the two ends of the cord; retrograde neuronal labelling indicated that supraspinal and propriospinal innervation spanned the injury site. This repair was associated with pronounced behavioural recovery, coordinated gait and an ability to use hindlimbs when swimming. Injury at P28 resulted in a cyst-like cavity encased in scar tissue forming at the injury site. Using retrograde labelling, no labelled brainstem or propriospinal neurons were found above the lesion, indicating that detectable neuronal connectivity had not spanned the injury site. However, these animals could use their hindlimbs to take weight-supporting steps but could not use their hindlimbs when swimming. White matter, demonstrated by Luxol Fast Blue staining, was present in the injury site of P7- but not P28-injured animals. Overall, these studies demonstrated that provided spinal injury occurs early in development, regrowth of supraspinal innervation is possible. This repair appears to lead to improved functional outcomes. At older ages, even without detectable axonal growth spanning the injury site, substantial development of locomotion was still possible. This outcome is discussed in conjunction with preliminary findings of differences in the local propriospinal circuits following spinal cord injury (demonstrated with fluororuby labelling), which may underlie the weight bearing locomotion observed in the apparent absence of

  17. Flood susceptibility mapping using a novel ensemble weights-of-evidence and support vector machine models in GIS

    NASA Astrophysics Data System (ADS)

    Tehrany, Mahyat Shafapour; Pradhan, Biswajeet; Jebur, Mustafa Neamah

    2014-05-01

    Flood is one of the most devastating natural disasters that occur frequently in Terengganu, Malaysia. Recently, ensemble based techniques are getting extremely popular in flood modeling. In this paper, weights-of-evidence (WoE) model was utilized first, to assess the impact of classes of each conditioning factor on flooding through bivariate statistical analysis (BSA). Then, these factors were reclassified using the acquired weights and entered into the support vector machine (SVM) model to evaluate the correlation between flood occurrence and each conditioning factor. Through this integration, the weak point of WoE can be solved and the performance of the SVM will be enhanced. The spatial database included flood inventory, slope, stream power index (SPI), topographic wetness index (TWI), altitude, curvature, distance from the river, geology, rainfall, land use/cover (LULC), and soil type. Four kernel types of SVM (linear kernel (LN), polynomial kernel (PL), radial basis function kernel (RBF), and sigmoid kernel (SIG)) were used to investigate the performance of each kernel type. The efficiency of the new ensemble WoE and SVM method was tested using area under curve (AUC) which measured the prediction and success rates. The validation results proved the strength and efficiency of the ensemble method over the individual methods. The best results were obtained from RBF kernel when compared with the other kernel types. Success rate and prediction rate for ensemble WoE and RBF-SVM method were 96.48% and 95.67% respectively. The proposed ensemble flood susceptibility mapping method could assist researchers and local governments in flood mitigation strategies.

  18. Structuring a life support program using evidence-based practice and the Magnet model for successful patient outcomes.

    PubMed

    Krugman, Mary; Paston, Kristin

    2013-01-01

    Integrating life support activities into an acute care academic hospital structure using evidence-based practice and the Magnet Model framework provides program operations and outcomes that are cost effective, link quality to life support professional development, and demonstrate excellence patient safety outcomes.

  19. Intraobserver and interobserver variability in the calculation of apparent diffusion coefficient (ADC) from diffusion-weighted magnetic resonance imaging (DW-MRI) of breast tumours.

    PubMed

    Petralia, G; Bonello, L; Summers, P; Preda, L; Malasevschi, A; Raimondi, S; Di Filippi, R; Locatelli, M; Curigliano, G; Renne, G; Bellomi, M

    2011-04-01

    This study evaluated intraobserver and interobserver variability in the measurement of apparent diffusion coefficient (ADC) values in breast carcinomas. Twenty-eight patients with solid breast lesions >10 mm underwent conventional contrast-enhanced magnetic resonance imaging (MRI) and diffusion-weighted MRI (DW-MRI). Two observers (expert and trainee) segmented the lesion from the surrounding breast tissue on DW images with high b-value (1,000 s/mm(2)). This analysis was repeated by the expert reader after 6 months. Volumes were analysed to obtain mean, median and standard deviation (SD) of the ADC values. Interobserver and intraobserver variation was analysed using the Bland-Altman graph. All lesions were breast carcinomas, with a mean ADC value of 1.07 × 10(-3) mm(2)/s. The mean of the differences was 0.012 × 10(-3) mm(2)/s, corresponding to an intraobserver variability of 1.1% (limits of agreement: -5%/+8%). The mean interobserver difference was 0.022 × 10(-3) mm(2)/s, corresponding to an interobserver variability of 2% (limits of agreement: -9%/+14%). We found a low intraobserver and interobserver variability in calculating ADC in breast carcinomas, which supports its potential use in routine clinical practice.

  20. Reduced Integration and Differentiation of the Imitation Network in Autism: A Combined Functional Connectivity Magnetic Resonance Imaging and Diffusion-Weighted Imaging Study

    PubMed Central

    Fishman, Inna; Datko, Michael; Cabrera, Yuliana; Carper, Ruth A.; Müller, Ralph-Axel

    2016-01-01

    Objective Converging evidence indicates that brain abnormalities in autism spectrum disorder (ASD) involve atypical network connectivity, but few studies have integrated functional with structural connectivity measures. This multimodal investigation examined functional and structural connectivity of the imitation network in children and adolescents with ASD, and its links with clinical symptoms. Methods Resting state functional magnetic resonance imaging and diffusion-weighted imaging were performed in 35 participants with ASD and 35 typically developing controls, aged 8 to 17 years, matched for age, gender, intelligence quotient, and head motion. Results Within-network analyses revealed overall reduced functional connectivity (FC) between distributed imitation regions in the ASD group. Whole brain analyses showed that underconnectivity in ASD occurred exclusively in regions belonging to the imitation network, whereas overconnectivity was observed between imitation nodes and extraneous regions. Structurally, reduced fractional anisotropy and increased mean diffusivity were found in white matter tracts directly connecting key imitation regions with atypical FC in ASD. These differences in microstructural organization of white matter correlated with weaker FC and greater ASD symptomatology. Interpretation Findings demonstrate atypical connectivity of the brain network supporting imitation in ASD, characterized by a highly specific pattern. This pattern of underconnectivity within, but overconnectivity outside the functional network is in contrast with typical development and suggests reduced network integration and differentiation in ASD. Our findings also indicate that atypical connectivity of the imitation network may contribute to ASD clinical symptoms, highlighting the role of this fundamental social cognition ability in the pathophysiology of ASD. PMID:26418284

  1. Advantages of susceptibility-weighted magnetic resonance sequences in the visualization of intravascular thrombi in acute ischemic stroke.

    PubMed

    Allibert, R; Billon Grand, C; Vuillier, F; Cattin, F; Muzard, E; Biondi, A; Moulin, T; Medeiros, E

    2014-12-01

    In gradient echo magnetic resonance imaging (MRI), intravascular thrombi (IT) can appear as vascular susceptibility artifacts, linked to local presence of intra-arterial deoxyhaemoglobin, and called susceptibility vessel signs (SVS). Our objectives were to evaluate the sensitivity of susceptibility-weighted sequences, such as T2* weighted angiography (SWAN) in the visualization of SVS compared with T2*, to consider whether it enabled a better understanding of the importance of SVS, and to compare cerebral circulation regulation profiles according to the localization of the SVS (i.e. proximal or distal). We prospectively studied the clinical and imaging data of 78 consecutive patients admitted for acute cerebral ischemia to the stroke unit of Besançon University Hospital between 1 April 2009 and 31 January 2010. An SVS was visualized in 44/78 (56%) patients using SWAN and in 13/78 (16%) patients using T2*. All the SVS visible using T2* were also visible on the SWAN. The inter-observer kappa score was 0·72 [CI (0·53-0·91)] for T2*, 0·72 [CI (0·57-0·87)] for SWAN, and weighted kappa was 0·77 [CI (0·61-0·92)] for both T2* and SWAN. When an MCA occlusion was visible on MRA imaging (22/78 patients), a SVS was visualized in 7/22 cases (31·8%) using T2* and in 20/22 cases (91%) using SWAN. When the occlusion was visible in the M1 or M2 segments (17/78 patients), an SVS was visualized in 6/17 cases (35·3%) using T2* and in 15/17 cases (88·2%) using SWAN. When the occlusion was visible in the M3 segment (5/78 patients), an SVS was visualized in 1/5 cases (20%) using T2* and in 5/5 cases (100%) using SWAN. Presence of SVS was not associated with cardioembolic etiology of the stroke. SWAN was more sensitive than T2* in the visualization of SVS in the intracranial arteries during the acute phase of ischemic stroke. Our study shows that the low number of SVS visualized using T2* in previous studies is probably related to a lack of sensitivity of the sequence, rather

  2. Use of Nuclear Magnetic Resonance as an Experimental Probe in Multiphase Systems: Determination of the Instrument Weight Function for Measurements of Liquid-Phase Volume Fractions

    NASA Astrophysics Data System (ADS)

    Maneval, J. E.; McCarthy, M. J.; Whitaker, S.

    1990-11-01

    The relativist approach (Baveye and Sposito (1984)) to the interpretation of measurements in multiphase systems was proposed in order to incorporate the details of measurements into theoretical analyses of multiphase transport processes. To help establish the utility of this approach, the weight functions for actual experimental probes must be determined. In this paper we analyze the measurement of liquid-phase porosity in a model system by nuclear magnetic resonance imaging. We show how both nuclear magnetic resonance (NMR) physics and experimental technique combine to determine the weight function for the spin-warp spin-echo sequence. The analysis shows clearly what aspects of the weight function are determined by the experimental method and what aspects are determined by the system being studied. The results will help establish the utility of the relativist approach as well as improve understanding NMR measurements in multiphase systems.

  3. The Application of Diffusion- and Perfusion-Weighted Magnetic Resonance Imaging in the Diagnosis and Therapy of Acute Cerebral Infarction

    PubMed Central

    Li, Enzhong; Tian, Jie; Chen, Jian; Wang, Huifang; Dai, Jianping

    2006-01-01

    Diffusion- and perfusion-weighted magnetic resonance imaging (DWI and PWI) was applied for stroke diagnose in 120 acute (< 48 h) ischemic stroke patients. At hyperacute (< 6 h) stage, it is difficult to find out the infarction zone in conventional T1 or T2 image, but it is easy in DWI, apparent diffusion coefficient (ADC) map; when at 3–6-hour stage it is also easy in PWI, cerebral blood flow (CBF) map, cerebral blood volume (CBV) map, and mean transit time (MTT) map; at acute (6–48 h) stage, DWI or PWI is more sensitive than conventional T1 or T2 image too. Combining DWI with ADC, acute and chronic infarction can be distinguished. Besides, penumbra which should be developed in meaning was used as an indication or to evaluate the therapeutic efficacy. There were two cases (< 1.5 h) that broke the model of penumbra because abnormity was found in DWI but not that in PWI, finally they recovered without any sequela. PMID:23165020

  4. Intravoxel Incoherent Motion Diffusion Weighted Magnetic Resonance Imaging for Differentiation Between Nasopharyngeal Carcinoma and Lymphoma at the Primary Site

    PubMed Central

    Yu, Xiao-Ping; Hou, Jing; Li, Fei-Ping; Wang, Hui; Hu, Ping-Sheng; Bi, Feng; Wang, Wei

    2016-01-01

    Objective The aim of the study was to investigate the utility of intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (DWI) for differentiating nasopharyngeal carcinoma (NPC) from lymphoma. Methods Intravoxel incoherent motion–based parameters including the apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudodiffusion coefficient (D*), perfusion fraction (f), and fD* (the product of D* and f) were retrospectively compared between 102 patients (82 with NPC, 20 with lymphoma) who received pretreatment IVIM DWI. Results Compared with lymphoma, NPC exhibited higher ADC, D, D*, fD* values (P < 0.001) and f value (P = 0.047). The optimal cutoff values (area under the curve, sensitivity, and specificity, respectively) for distinguishing the 2 tumors were as follows: ADC value of 0.761 × 10−3 mm2/s (0.781, 93.90%, 55.00%); D, 0.66 × 10−3 mm2/s (0.802, 54.88%, 100.00%); D*, 7.89 × 10−3 mm2/s (0.898, 82.93%, 85.00%); f, 0.29 (0.644, 41.46%, 95.00%); and fD*, 1.99 × 10−3 mm2/s (0.960, 85.37%, 100.00%). Conclusions Nasopharyngeal carcinoma exhibits different IVIM-based imaging features from lymphoma. Intravoxel incoherent motion DWI is useful for differentiating lymphoma from NPC. PMID:26953769

  5. ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

    SciTech Connect

    Luna, M.; Moreno-Insertis, F.; Priest, E.

    2015-07-20

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

  6. Assembly of high molecular weight complexes of lipin on a supported lipid bilayer observed by atomic force microscopy.

    PubMed

    Creutz, Carl E; Eaton, James M; Harris, Thurl E

    2013-07-30

    Lipins are phosphatidic acid phosphatases involved in the biosynthesis of triacylglycerols and phospholipids. They are associated with the endoplasmic reticulum but can also travel into the nucleus and alter gene expression. Previous studies indicate lipins in solution form high molecular weight complexes, possibly tetramers. This study was undertaken to determine if lipins form complexes on membranes as well. Murine lipin 1b was applied to a supported bilayer of phosphatidylcholine, phosphatidylserine, and cholesterol and examined by atomic force microscopy (AFM) over time. Lipin on bare mica appeared as a symmetric particle with a volume consistent with the size of a monomer. On the bilayer, lipin initially bound as asymmetric, curved particles that sometimes assembled into circular structures with an open center. Subsequently, lipin assemblies grew into large, symmetric particles with an average volume 12 times that of the monomer. Over time, some of the lipin assemblies were removed from the bilayer by the AFM probe leaving behind "footprints" composed of complex patterns that may reflect the substructure of the lipin assemblies. The lipin complexes appeared very flat, with a diameter 20 times their height. The footprints had a similar diameter, providing confirmation of the extensive deformation of the protein under the AFM probe. The ability of lipin to form large complexes on membranes may have significant implications for the local concentrations of the product, diacylglycerol, formed during hydrolysis of phosphatidic acid and for cooperative hormonal regulation of lipin activity through phosphorylation of one or more monomers in the complexes.

  7. Development of body weight support gait training system using pneumatic Mckibben actuators -control of lower extremity orthosis.

    PubMed

    Mat Dzahir, M A; Nobutomo, T; Yamamoto, S I

    2013-01-01

    Recently, robot assisted therapy devices are increasingly used for spinal cord injury (SCI) rehabilitation in assisting handicapped patients to regain their impaired movements. Assistive robotic systems may not be able to cure or fully compensate impairments, but it should be able to assist certain impaired functions and ease movements. In this study, the control system of lower extremity orthosis for the body weight support gait training system which implements pneumatic artificial muscle (PAM) is proposed. The hip and knee joint angles of the gait orthosis system are controlled based on the PAM coordinates information from the simulation. This information provides the contraction data for the mono- and bi-articular PAMs that are arranged as posterior and anterior actuators to simulate the human walking motion. The proposed control system estimates the actuators' contraction as a function of hip and knee joint angles. Based on the contraction model obtained, input pressures for each actuators are measured. The control system are performed at different gait cycles and two PMA settings for the mono- and bi-articular actuators are evaluated in this research. The results showed that the system was able to achieve the maximum muscle moment at the joints, and able to perform the heel contact movement. This explained that the antagonistic mono- and bi-articular actuators worked effectively.

  8. ASSEMBLY OF HIGH MOLECULAR WEIGHT COMPLEXES OF LIPIN ON A SUPPORTED LIPID BILAYER OBSERVED BY ATOMIC FORCE MICROSCOPY

    PubMed Central

    Creutz, Carl E.; Eaton, James M.; Harris, Thurl E.

    2014-01-01

    Lipins are phosphatidic acid phosphatases involved in the biosynthesis of triacylglycerols and phospholipids. They are associated with the endoplasmic reticulum but can also travel into the nucleus and alter gene expression. Previous studies indicate lipins in solution form high molecular weight complexes, possibly tetramers. This study was undertaken to determine if lipins form complexes on membranes as well. Murine lipin 1b was applied to a supported bilayer of phosphatidylcholine, phosphatidylserine, and cholesterol and examined by atomic force microscopy (AFM) over time. Lipin on bare mica appeared as a symmetric particle with a volume consistent with the size of a monomer. On the bilayer lipin initially bound as asymmetric, curved particles which sometimes assembled into circular structures with an open center. Subsequently, lipin assemblies grew into large, symmetric particles with an average volume twelve times that of the monomer. Over time some of the lipin assemblies were removed from the bilayer by the AFM probe leaving behind “footprints” composed of complex patterns that may reflect the substructure of the lipin assemblies. The lipin complexes appeared very flat, with a diameter 20 times their height. The footprints had a similar diameter, providing confirmation of the extensive deformation of the protein under the AFM probe. The ability of lipin to form large complexes on membranes may have significant implications for the local concentrations of the product, diacylglycerol, formed during hydrolysis of phosphatidic acid and for cooperative hormonal regulation of lipin activity through phosphorylation of one or more monomers in the complexes. PMID:23862673

  9. Body weight supported treadmill training versus traditional training in patients dependent on walking assistance after stroke: a randomized controlled trial.

    PubMed

    Høyer, Ellen; Jahnsen, Reidun; Stanghelle, Johan Kvalvik; Strand, Liv Inger

    2012-01-01

    Treadmill training with body weight support (TTBWS) for relearning walking ability after brain damage is an approach under current investigation. Efficiency of this method beyond traditional training is lacking evidence, especially in patients needing walking assistance after stroke. The objective of this study was to investigate change in walking and transfer abilities, comparing TTBWS with traditional walking training. A single-blinded, randomized controlled trial was conducted. Sixty patients referred for multi-disciplinary primary rehabilitation were assigned into one of two intervention groups, one received 30 sessions of TTBWS plus traditional training, the other traditional training alone. Daily training was 1 hr. Outcome measures were Functional Ambulation Categories (FAC), Walking, Functional Independence Measure (FIM); shorter transfer and stairs, 10 m and 6-min walk tests. Substantial improvements in walking and transfer were shown within both groups after 5 and 11 weeks of intervention. Overall no statistical significant differences were found between the groups, but 12 of 17 physical measures tended to show improvements in favour of the treadmill approach. Both training strategies provided significant improvements in the tested activities, suggesting that similar outcomes can be obtained in the two modalities by systematic, intensive and goal directed training.

  10. Efficacy and acceptance of a commercial Hoodia parviflora product for support of appetite and weight control in a consumer trial.

    PubMed

    Landor, Michael; Benami, Ari; Segev, Nitzan; Loberant, Beth

    2015-02-01

    Species of Hoodia Sweet ex Decne., family Apocynaceae, a southern African succulent plant, have been recognized for their appetite suppressing properties. Products that support appetite and weight control have been developed in Israel from locally cultivated Hoodia spp. To study consumer acceptance, efficacy of, and tolerance for a frozen product based on whole aerial parts of Hoodia parviflora N.E. Br., we initiated and conducted this single-blind, randomized, placebo-controlled consumer trial. Volunteer participants ingested flavored 3 g frozen Hoodia or placebo cubes for 40 days. Subjects were weighed and measured and baseline body-mass index was determined. Adverse events were monitored and eight mild, transient, possible treatment-emergent events were reported. No moderate, severe, or chronic events were reported. On days 1, 10, and 40, subjects self-reported their perceptions of food consumption, hunger development, incidence and control of food cravings, and efficacy of the product. On day 40, the treatment group demonstrated a statistically significant decrease in measured quantitative parameters against the placebo and reported a positive perception of the product.

  11. Differentiation of neurodegenerative parkinsonian syndromes by volumetric magnetic resonance imaging analysis and support vector machine classification.

    PubMed

    Huppertz, Hans-Jürgen; Möller, Leona; Südmeyer, Martin; Hilker, Rüdiger; Hattingen, Elke; Egger, Karl; Amtage, Florian; Respondek, Gesine; Stamelou, Maria; Schnitzler, Alfons; Pinkhardt, Elmar H; Oertel, Wolfgang H; Knake, Susanne; Kassubek, Jan; Höglinger, Günter U

    2016-10-01

    Clinical differentiation of parkinsonian syndromes is still challenging. A fully automated method for quantitative MRI analysis using atlas-based volumetry combined with support vector machine classification was evaluated for differentiation of parkinsonian syndromes in a multicenter study. Atlas-based volumetry was performed on MRI data of healthy controls (n = 73) and patients with PD (204), PSP with Richardson's syndrome phenotype (106), MSA of the cerebellar type (21), and MSA of the Parkinsonian type (60), acquired on different scanners. Volumetric results were used as input for support vector machine classification of single subjects with leave-one-out cross-validation. The largest atrophy compared to controls was found for PSP with Richardson's syndrome phenotype patients in midbrain (-15%), midsagittal midbrain tegmentum plane (-20%), and superior cerebellar peduncles (-13%), for MSA of the cerebellar type in pons (-33%), cerebellum (-23%), and middle cerebellar peduncles (-36%), and for MSA of the parkinsonian type in the putamen (-23%). The majority of binary support vector machine classifications between the groups resulted in balanced accuracies of >80%. With MSA of the cerebellar and parkinsonian type combined in one group, support vector machine classification of PD, PSP and MSA achieved sensitivities of 79% to 87% and specificities of 87% to 96%. Extraction of weighting factors confirmed that midbrain, basal ganglia, and cerebellar peduncles had the largest relevance for classification. Brain volumetry combined with support vector machine classification allowed for reliable automated differentiation of parkinsonian syndromes on single-patient level even for MRI acquired on different scanners. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

  12. Structure and Stability of Filamentary Clouds Supported by Lateral Magnetic Field

    NASA Astrophysics Data System (ADS)

    Hanawa, Tomoyuki; Tomisakar, Kohji

    We have constructed two types of analytical models for an isothermal filamentary cloud supported mainly by magnetic tension. The first one describes an isolated cloud while the second considers filamentary clouds spaced periodically. The filamentary clouds are assumed to be highly flattened in both the models. The former is proved to be the asymptotic limit of the latter in which each filamentary cloud is much thinner than the distance to the neighboring filaments. These models show that the mass to flux ratio is crucial for the magnetohydrodynamical equilibrium. The upper bound for the line density, i.e., the mass per unit length, is proportional to the magnetic flux. The mass to flux ratio is slightly larger than the critical value, ( )-1, in the first model and lower in the second model. The first model is unstable against fragmentation and the wavelength of the fastest growing mode is several times longer than the cloud diameter. The second model is likely to be unstable only when the mass to flux ratio is supercritical.

  13. Hybrid RGSA and Support Vector Machine Framework for Three-Dimensional Magnetic Resonance Brain Tumor Classification

    PubMed Central

    Rajesh Sharma, R.; Marikkannu, P.

    2015-01-01

    A novel hybrid approach for the identification of brain regions using magnetic resonance images accountable for brain tumor is presented in this paper. Classification of medical images is substantial in both clinical and research areas. Magnetic resonance imaging (MRI) modality outperforms towards diagnosing brain abnormalities like brain tumor, multiple sclerosis, hemorrhage, and many more. The primary objective of this work is to propose a three-dimensional (3D) novel brain tumor classification model using MRI images with both micro- and macroscale textures designed to differentiate the MRI of brain under two classes of lesion, benign and malignant. The design approach was initially preprocessed using 3D Gaussian filter. Based on VOI (volume of interest) of the image, features were extracted using 3D volumetric Square Centroid Lines Gray Level Distribution Method (SCLGM) along with 3D run length and cooccurrence matrix. The optimal features are selected using the proposed refined gravitational search algorithm (RGSA). Support vector machines, over backpropagation network, and k-nearest neighbor are used to evaluate the goodness of classifier approach. The preliminary evaluation of the system is performed using 320 real-time brain MRI images. The system is trained and tested by using a leave-one-case-out method. The performance of the classifier is tested using the receiver operating characteristic curve of 0.986 (±002). The experimental results demonstrate the systematic and efficient feature extraction and feature selection algorithm to the performance of state-of-the-art feature classification methods. PMID:26509188

  14. Permanent Magnet Synchronous Condenser for Wind Power Plant Grid Connection Support: Preprint

    SciTech Connect

    Hsu, P.; Muljadi, E.

    2015-04-03

    A synchronous condenser (SC) using a permanent magnet synchronous generator (PMSG) is proposed for providing necessary reactive power to a wind power plant to support its connection to a weak grid. A PMSG has the advantage of higher efficiency and reliability. Because of its lack of a field winding, a PMSG is typically controlled by a full-power converter, which can be costly. In the proposed system, the reactive power of the SC is controlled by a serially connected compensator operating in a closed-loop configuration. The compensator also damps the PMSG's tendency to oscillate. The compensator's VA rating is only a fraction of the rating of the SC and the PMSG. In this initial investigation, the proposed scheme is shown to be effective by computer simulations.

  15. The relationships among stress, coping, social support, and weight class in premenopausal African American women at risk for coronary heart disease.

    PubMed

    Strickland, Ora Lea; Giger, Joyce Newman; Nelson, Michelle A; Davis, Claudia M

    2007-01-01

    The purpose of this study was to determine the nature of the relationships among stress, coping, social support, and weight class in premenopausal African American women as risk factors for coronary heart disease. Overweight and obesity are significant problems for African American women who are at an increased risk of weight-related diseases, such as diabetes, hypertension, cardiovascular disease, and cancer. Of these women, those who are premenopausal have a significantly higher coronary heart disease mortality rate than their white counterparts. There are gaps in current knowledge concerning the role that stress and other psychosocial factors play in weight control of premenopausal African American women. Data were obtained from 178 women with eligible data sets from a larger study of 236 subjects (Genetic Predictors of Coronary Heart Disease in Premenopausal African American Women). The measures for stress, coping, and social support included the Perceived Stress Scale, the Norbeck Social Support Questionnaire, and the Jalowiec Coping Scale. The weight class of the women was determined as: normal weight-body mass index (BMI) of 18.5-24.9 kg/m, overweight-BMI of 25-29.9 kg/m, or obese-BMI > or = 30 kg/m. Statistical analysis conducted included Spearman's rho, Chi-square, and regression analysis. Confrontive coping was shown to be used more often to a "high" degree in normal-weight African American women than in overweight and obese African American women (chi = 24.024; P = .0001). Confrontive coping was the only independent predictor of weight class in a regression model that included perceived stress, life events, social support, and optimistic, self-reliant, and evasive coping strategies. Therefore, African American women who use confrontive coping to a high degree were more likely to confront problems, such as weight control issues, than those who use this coping strategy to a low or medium degree.

  16. Physiological Background of Differences in Quantitative Diffusion-Weighted Magnetic Resonance Imaging Between Acute Malignant and Benign Vertebral Body Fractures: Correlation of Apparent Diffusion Coefficient With Quantitative Perfusion Magnetic Resonance Imaging Using the 2-Compartment Exchange Model.

    PubMed

    Geith, Tobias; Biffar, Andreas; Schmidt, Gerwin; Sourbron, Steven; Dietrich, Olaf; Reiser, Maximilian; Baur-Melnyk, Andrea

    2015-01-01

    To test the hypothesis that apparent diffusion coefficient (ADC) in vertebral bone marrow of benign and malignant fractures is related to the volume of the interstitial space, determined with dynamic contrast-enhanced (DCE) magnetic resonance imaging. Patients with acute benign (n = 24) and malignant (n = 19) vertebral body fractures were examined at 1.5 T. A diffusion-weighted single-shot turbo-spin-echo sequence (b = 100 to 600 s/mm) and DCE turbo-FLASH sequence were evaluated. Regions of interest were manually selected for each fracture. Apparent diffusion coefficient was determined with a monoexponential decay model. The DCE magnetic resonance imaging concentration-time curves were analyzed using a 2-compartment tracer-kinetic model. Apparent diffusion coefficient showed a significant positive correlation with interstitial volume in the whole study population (Pearson r = 0.66, P < 0.001), as well as in the malignant (Pearson r = 0.64, P = 0.004) and benign (Pearson r = 0.52, P = 0.01) subgroup. A significant correlation between ADC and the permeability-surface area product could be observed when analyzing the whole study population (Spearman rs = 0.40, P = 0.008), but not when separately examining the subgroups. Plasma flow showed a significant correlation with ADC in benign fractures (Pearson r = 0.23, P = 0.03). Plasma volume did not show significant correlations with ADC. The results support the hypothesis that the ADC of a lesion is inversely correlated to its cellularity. This explains previous observations that ADC is reduced in more malignant lesions.

  17. Combining Persuasive Technology With Behavioral Theory to Support Weight Maintenance Through a Mobile Phone App: Protocol for the MotiMate App

    PubMed Central

    Hendrie, Gilly A; Freyne, Jill

    2016-01-01

    Background The prevalence of health-focused mobile phone apps available for download increases daily, with weight management apps being among the most proliferative. However, most lack theoretic grounding or evidence of efficacy. There is a significant body of literature which provides evidence for behaviors which are associated with successful weight loss maintenance. Behavioral theory also provides further insight regarding successful behavior change and maintenance. Objective We aimed to apply this knowledge to the development of the functionality of an app targeting weight loss maintenance. Methods We have subsequently undertaken the development of a persuasive and behavior targeting mobile app (MotiMate) to assist in maintenance of weight loss. MotiMate combines persuasive and behavior change theories in a practical targeted tool through its motivational messages, personalized feedback, and intelligent supportive tools to manage weight, food, exercise, mood and stress. Results The development and trial of MotiMate received funding support in May 2014. All 88 volunteers started the trial by December 2014 and were in the process of completing their final visits when this paper was submitted (May 2015). Data analysis is currently underway. Conclusions The paper has presented a scientifically informed mobile phone app to support weight loss maintenance. Further evaluation of its efficacy is in progress. Trial Registration ANZCTR 12614000474651; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366120 (Archived by WebCite at http://www.webcitation.org/6eJeQiKxi). PMID:26747725

  18. Combining Persuasive Technology With Behavioral Theory to Support Weight Maintenance Through a Mobile Phone App: Protocol for the MotiMate App.

    PubMed

    Brindal, Emily; Hendrie, Gilly A; Freyne, Jill

    2016-01-08

    The prevalence of health-focused mobile phone apps available for download increases daily, with weight management apps being among the most proliferative. However, most lack theoretic grounding or evidence of efficacy. There is a significant body of literature which provides evidence for behaviors which are associated with successful weight loss maintenance. Behavioral theory also provides further insight regarding successful behavior change and maintenance. We aimed to apply this knowledge to the development of the functionality of an app targeting weight loss maintenance. We have subsequently undertaken the development of a persuasive and behavior targeting mobile app (MotiMate) to assist in maintenance of weight loss. MotiMate combines persuasive and behavior change theories in a practical targeted tool through its motivational messages, personalized feedback, and intelligent supportive tools to manage weight, food, exercise, mood and stress. The development and trial of MotiMate received funding support in May 2014. All 88 volunteers started the trial by December 2014 and were in the process of completing their final visits when this paper was submitted (May 2015). Data analysis is currently underway. The paper has presented a scientifically informed mobile phone app to support weight loss maintenance. Further evaluation of its efficacy is in progress. ANZCTR 12614000474651; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366120 (Archived by WebCite at http://www.webcitation.org/6eJeQiKxi).

  19. Symmetry-Supported Magnetic Blocking at 20 K in Pentagonal Bipyramidal Dy(III) Single-Ion Magnets.

    PubMed

    Chen, Yan-Cong; Liu, Jun-Liang; Ungur, Liviu; Liu, Jiang; Li, Quan-Wen; Wang, Long-Fei; Ni, Zhao-Ping; Chibotaru, Liviu F; Chen, Xiao-Ming; Tong, Ming-Liang

    2016-03-02

    Single-molecule magnets (SMMs) that can be trapped in one of the bistable magnetic states separated by an energy barrier are among the most promising candidates for high-density information storage, quantum processing, and spintronics. To date, a considerable series of achievements have been made. However, the presence of fast quantum tunnelling of magnetization (QTM) in most SMMs, especially in single-ion magnets (SIMs), provides a rapid relaxation route and often sets up a limit for the relaxation time. Here, we pursue the pentagonal bipyramidal symmetry to suppress the QTM and present pentagonal bipyramidal Dy(III) SIMs [Dy(Cy3PO)2(H2O)5]Cl3·(Cy3PO)·H2O·EtOH (1) and [Dy(Cy3PO)2(H2O)5]Br3·2(Cy3PO)·2H2O·2EtOH (2), (Cy3PO = tricyclohexyl phosphine oxide). Magnetic characterizations reveal their fascinating SMM properties with high energy barriers as 472(7) K for 1 and 543(2) K for 2, along with a record magnetic hysteresis temperature up to 20 K for 2. These results, combined with the ab initio calculations, offer an illuminating insight into the vast possibility and potential of what the symmetry rules can achieve in molecular magnetism.

  20. Impact of food support on food security and body weight among HIV antiretroviral therapy recipients in Honduras: a pilot intervention trial.

    PubMed

    Palar, Kartika; Derose, Kathryn Pitkin; Linnemayr, Sebastian; Smith, Alexandria; Farías, Hugo; Wagner, Glenn; Martinez, Homero

    2015-01-01

    Optimal strategies to improve food security and nutrition for people living with HIV (PLHIV) may differ in settings where overweight and obesity are prevalent and cardiovascular disease risk is a concern. However, no studies among PLHIV have investigated the impact of food support on nutritional outcomes in these settings. We therefore assessed the effect of food support on food insecurity and body weight in a population of PLHIV with high prevalence of overweight and obesity. We implemented a pilot intervention trial in four government-run HIV clinics in Honduras. The trial tested the effect of a monthly household food ration plus nutrition education (n = 203), compared to nutrition education alone (n = 197), over 12 months. Participants were clinic patients receiving antiretroviral therapy (ART). Assessments were obtained at baseline, 6 and 12 months. Primary outcomes for this analysis were food security, using the validated Latin American and Caribbean Food Security Scale and body weight (kg). Thirty-one percent of participants were overweight (22%) or obese (8%) at baseline. At 6 months, the probability of severe food insecurity decreased by 48.3% (p < 0.01) in the food support group, compared to 11.6% in the education-only group (p < 0.01). Among overweight or obese participants, food support led to average weight gain of 1.13 kg (p < 0.01), while nutrition education alone was associated with average weight loss of 0.72 kg (p < 0.10). Nutrition education alone was associated with weight gain among underweight and normal weight participants. Household food support may improve food security but not necessarily nutritional status of ART recipients above and beyond nutrition education. Improving nutritional tailoring of food support and testing the impact of nutrition education should be prioritized for PLHIV in Latin America and similar settings.

  1. Dietary counselling and nutritional support in oropharyngeal cancer patients treated with radiotherapy: persistent weight loss during 1-year follow-ups.

    PubMed

    Vlooswijk, C P; van Rooij, P H E; Kruize, J C; Schuring, H A; Al-Mamgani, A; de Roos, N M

    2016-01-01

    The need for dietary counselling and nutritional support in oropharyngeal cancer patients is generally accepted. However, evidence for the effectiveness is sparse. The aim of this study was to describe dietary counselling, nutritional support, body weight and toxicity during and after treatment, and investigate the effect of pre-treatment body mass index (BMI) on survival in oropharyngeal cancer patients. A retrospective chart review was made in 276 oropharyngeal cancer patients treated with radiotherapy (RT). End points were dietary consultations, weight loss, toxicity, overall survival and disease-free survival. Almost all oropharyngeal cancer patients received dietary counselling (94%) and nutritional support (99%). Dietary counselling decreased sharply shortly after treatment to 38% at 1 year after treatment. Overall weight loss increased during the first year of follow-up and ranged from 3% at start of RT, until 11% at 1 year after RT. Overall survival was significantly longer for patients with a BMI above average (P=0.01). Acute dysphagia (P=0.001), mucositis (P=0.000) and toxicity grade 3 (P=0.002) were significantly more prevalent in patients who had lost 10% or more of their body weight. This study showed that patients continue to lose body weight during and until 1 year after treatment, despite nutrition support and frequent dietetic consultation. A BMI above average appears to increase survival time. Future studies, preferably randomized trials, are needed to compare standard dietary counselling with more intensive dietary counselling that consists of earlier and/or prolonged treatment.

  2. Clinical utility of optimized three-dimensional T1-, T2-, and T2*-weighted sequences in spinal magnetic resonance imaging.

    PubMed

    Tanitame, Nobuko; Tanitame, Keizo; Awai, Kazuo

    2017-02-23

    This article reviews the clinical utility of 3D magnetic resonance imaging (MRI) sequences optimized for the evaluation of various intraspinal lesions. First, intraspinal tumors with hypervascular components and arteriovenous malformations (AVM) are clearly shown on contrast-enhanced (CE)-3D T1-weighted gradient-echo (GE) sequences with high spatial resolution. Second, dynamic CE-3D time-resolved magnetic resonance angiography (MRA) shows delineated feeding arteries of intraspinal AVM or arteriovenous fistula (AVF), greatly aiding subsequent digital subtraction angiography (DSA). Third, 3D multiecho T2*-weighted GE sequences are used to visualize intraspinal structures and spinal cord lesions and are sensitive to the magnetic susceptibility of intraspinal hemorrhages. Three-dimensional balanced steady-state free precession (SSFP) and multishot 3D balanced non-SSFP sequences produce contiguous thin images with high signal-to-noise ratio (SNR) in short scanning times. Intraspinal cystic lesions and small nerve-root tumors in subarachnoid space can be viewed using 3D balanced SSFP. Spinal cord myelomalacia and cord compression can be evaluated on fat-suppressed multishot 3D balanced non-SSFP. Finally, a 3D T2-weighted fast spin-echo (FSE) sequence with variable flip angle (FA) refocusing pulse improves through-plane spatial resolution over conventional 2D T2-weighted FSE sequences while matching image contrast.

  3. Magnetic resonance imaging of blood-brain barrier permeability in ischemic stroke using diffusion-weighted arterial spin labeling in rats.

    PubMed

    Tiwari, Yash V; Lu, Jianfei; Shen, Qiang; Cerqueira, Bianca; Duong, Timothy Q

    2016-01-01

    Diffusion-weighted arterial spin labeling magnetic resonance imaging has recently been proposed to quantify the rate of water exchange (Kw) across the blood-brain barrier in humans. This study aimed to evaluate the blood-brain barrier disruption in transient (60 min) ischemic stroke using Kw magnetic resonance imaging with cross-validation by dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology in the same rats. The major findings were: (i) at 90 min after stroke (30 min after reperfusion), group Kw magnetic resonance imaging data showed no significant blood-brain barrier permeability changes, although a few animals showed slightly abnormal Kw. Dynamic contrast-enhanced magnetic resonance imaging confirmed this finding in the same animals. (ii) At two days after stroke, Kw magnetic resonance imaging revealed significant blood-brain barrier disruption. Regions with abnormal Kw showed substantial overlap with regions of hyperintense T2 (vasogenic edema) and hyperperfusion. Dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology confirmed these findings in the same animals. The Kw values in the normal contralesional hemisphere and the ipsilesional ischemic core two days after stroke were: 363 ± 17 and 261 ± 18 min(-1), respectively (P < 0.05, n = 9). Kw magnetic resonance imaging is sensitive to blood-brain barrier permeability changes in stroke, consistent with dynamic contrast-enhanced magnetic resonance imaging and Evans blue extravasation. Kw magnetic resonance imaging offers advantages over existing techniques because contrast agent is not needed and repeated measurements can be made for longitudinal monitoring or averaging.

  4. A study of diffusion-weighted magnetic resonance imaging in men with untreated localised prostate cancer on active surveillance.

    PubMed

    van As, Nicholas J; de Souza, Nandita M; Riches, Sophie F; Morgan, Veronica A; Sohaib, Sayid A; Dearnaley, David P; Parker, Chris C

    2009-12-01

    Markers that predict the behaviour of localised prostate cancer are needed to identify patients that require treatment. We have analysed the apparent diffusion coefficient (ADC) generated from diffusion-weighted magnetic resonance imaging (DW-MRI) with respect to repeat biopsy findings and time to radical treatment in patients in a prospective study of active surveillance. Some 86 men recruited between 2002 and 2006 were followed for a median of 29 mo. Patients had clinical stage T1/T2a N0/Nx M0/Mx adenocarcinoma of the prostate, prostate-specific antigen (PSA) level<15 ng/ml, Gleason score≤7, primary Gleason grade≤3, and positive biopsy cores (pbc)≤50%. All patients had DW-MRI in addition to standard MRI sequences. Tumour regions of interest (ROIs) were identified using T2-weighted fast-spin echo images as focal areas of restricted diffusion. Univariate analyses including all clinical variables and tumour ADC data were performed with respect to repeat biopsy findings and time to radical treatment. Receiver operating curves (ROC) compared predictive variables. Patients in the study had a median age of 66 yr and a median initial PSA level of 6.7 ng/ml. Some 39 patients (45%) received deferred radical treatment, and 34 patients (40%) had adverse histology on repeat biopsy. According to univariate analysis, tumour ADC was a significant predictor of both adverse repeat biopsy findings (p<0.0001; hazard ratio [HR]: 1.3; 95% confidence interval [CI]: 1.1-1.6), and time to radical treatment (p<0.0001; HR: 1.5; 95% CI: 1.2-1.8). ROC curves for ADC showed an area under the curve (AUC) of 0.7 for prediction of adverse repeat biopsy findings and an AUC of 0.83 for prediction of radical treatment. In patients with low-risk, localised disease, tumour ADC on DW-MRI may be a useful marker of prostate cancer progression and may help to identify patients who stand to benefit from radical treatment. This possibility warrants further study.

  5. Temporal and spatial characteristics of the area at risk investigated using computed tomography and T1-weighted magnetic resonance imaging

    PubMed Central

    van der Pals, Jesper; Hammer-Hansen, Sophia; Nielles-Vallespin, Sonia; Kellman, Peter; Taylor, Joni; Kozlov, Shawn; Hsu, Li-Yueh; Chen, Marcus Y.; Arai, Andrew E.

    2015-01-01

    Aims Cardiovascular magnetic resonance (CMR) imaging can measure the myocardial area at risk (AAR), but the technique has received criticism for inadequate validation. CMR commonly depicts an AAR that is wider than the infarct, which in turn would require a lateral perfusion gradient within the AAR. We investigated the presence of a lateral perfusion gradient within the AAR and validated CMR measures of AAR against three independent reference standards of high quality. Methods and results Computed tomography (CT) perfusion imaging, microsphere blood flow analysis, T1-weighted 3T CMR and fluorescent microparticle pathology were used to investigate the AAR in a canine model (n = 10) of ischaemia and reperfusion. AAR size by CMR correlated well with CT (R2 = 0.80), microsphere blood flow (R2 = 0.80), and pathology (R2 = 0.74) with good limits of agreement [−0.79 ± 4.02% of the left ventricular mass (LVM) vs. CT; −1.49 ± 4.04% LVM vs. blood flow and −1.01 ± 4.18% LVM vs. pathology]. The lateral portion of the AAR had higher perfusion than the core of the AAR by CT perfusion imaging (40.7 ± 11.8 vs. 25.2 ± 17.7 Hounsfield units, P = 0.0008) and microsphere blood flow (0.11 ± 0.04 vs. 0.05 ± 0.02 mL/g/min, lateral vs. core, P = 0.001). The transmural extent of MI was lower in the lateral portion of the AAR than the core (28.2 ± 10.2 vs. 17.4 ± 8.4% of the wall, P = 0.001). Conclusion T1-weighted CMR accurately quantifies size of the AAR with excellent agreement compared with three independent reference standards. A lateral perfusion gradient results in lower transmural extent of infarction at the edges of the AAR compared with the core. PMID:25881901

  6. Hepatocellular carcinoma with central scar on gadoxetic acid-enhanced and diffusion-weighted magnetic resonance imaging.

    PubMed

    Han, Sol Bee; Kim, Young Kon; Min, Ji Hye; Ha, Sang Yun; Jeong, Woo Kyung; Lee, Won Jae

    2017-01-01

    Background Central scars are rarely reported in conventional hepatocellular carcinoma (HCC). The presence of central scars on imaging might lead to erroneous diagnosis of hepatic tumors. Purpose To determine imaging features of HCC with central scars on magnetic resonance imaging (MRI) including gadoxetic acid-enhanced and diffusion-weighted imaging (DWI). Material and Methods Fifty-one patients with 51 surgically confirmed HCCs with central scars (fibrotic scar: n = 50; myxoid scar: n = 1; range = 1.2-15 cm; mean = 3.7 cm) underwent liver MRI that consisted of T1- and T2-weighted (T2W) imaging, gadoxetic acid-enhanced arterial, portal, 3-min late phase, and 20-min hepatobiliary phase (HBP), and DWI. Two reviewers evaluated morphology, signal intensity, and enhancement features of tumors and central scars for each image and reached consensus. Results Lobulated contour was seen for 30 tumors (58.8%); the rest were round or oval masses. Central scars (range = 0.2-6.0 cm; mean = 0.9 cm) were most commonly seen as defects within hyperenhancement on arterial phase images (n = 47, 92.2%), bright (n = 28, 54.9%) or dark areas (n = 15, 29.4%) on T2W imaging, areas of central darkness on high b-value DWI (b = 800) (n = 31, 60.8%), and/or central enhancement on HBP (n = 36, 70.6%), mimicking a target appearance. Tumor capsule was seen in 35 (39 pathology, 74.5%) and intratumoral septum in 35 (41 pathology, 78.4%) tumors on gadoxetic acid-enhanced MRI. Conclusion Non-fibrolamellar HCC may show central scar. HCC with central scar mimics cholangiocarcinoma by showing a target appearance on HBP and DWI. Tumor capsule and intratumoral septum might be useful for characterizing HCC with central scar.

  7. Herbig stars' near-infrared excess: An origin in the protostellar disk's magnetically supported atmosphere

    SciTech Connect

    Turner, N. J.; Benisty, M.; Dullemond, C. P.; Hirose, S.

    2014-01-01

    Young stars with masses 2-8 times solar, the Herbig Ae and Be stars, often show a near-infrared excess too large to explain with a hydrostatically supported circumstellar disk of gas and dust. At the same time, the accretion flow carrying the circumstellar gas to the star is thought to be driven by magnetorotational turbulence, which, according to numerical MHD modeling, yields an extended low-density atmosphere supported by the magnetic fields. We demonstrate that the base of the atmosphere can be optically thick to the starlight and that the parts lying near 1 AU are tall enough to double the fraction of the stellar luminosity reprocessed into the near-infrared. We generate synthetic spectral energy distributions (SEDs) using Monte Carlo radiative transfer calculations with opacities for submicron silicate and carbonaceous grains. The synthetic SEDs closely follow the median Herbig SED constructed recently by Mulders and Dominik and, in particular, match the large near-infrared flux, provided the grains have a mass fraction close to interstellar near the disk's inner rim.

  8. Success in Weight Management Among Patients with Type 2 Diabetes: Do Perceived Autonomy Support, Autonomous Motivation, and Self-Care Competence Play a Role?

    PubMed

    Koponen, Anne M; Simonsen, Nina; Suominen, Sakari B

    2017-03-21

    Based on self-determination theory (SDT), this study investigated whether the three central SDT variables-perceived autonomy support (from a physician), autonomous motivation and self-care competence-were associated with success in weight management (SWM) among primary care patients with type 2 diabetes when the effect of other important life-context factors was controlled for. Patients participated in a mail survey in 2011. Those who had tried to change their health behavior during the past two years in order to lose weight, either with or without success (n = 1433, mean age 63 years, 50% men), were included in this study. The successors were more autonomously motivated and energetic than the non-successors. Moreover, male gender, younger age, taking oral medication only, and receiving less social support in diabetes care predicted better success. Autonomous motivation predicted SWM; self-care competence also played a role by partly mediating the effect of autonomous motivation on SWM. These results support the idea of SDT that internalizing the value of weight management and its health benefits is necessary for long-term maintenance of health behavior change. Perceived autonomy support was not directly associated with SWM. However, physicians can promote patients' weight management by supporting their autonomous motivation and self-care competence.

  9. How Energy Metabolism Supports Cerebral Function: Insights from 13C Magnetic Resonance Studies In vivo

    PubMed Central

    Sonnay, Sarah; Gruetter, Rolf; Duarte, João M. N.

    2017-01-01

    Cerebral function is associated with exceptionally high metabolic activity, and requires continuous supply of oxygen and nutrients from the blood stream. Since the mid-twentieth century the idea that brain energy metabolism is coupled to neuronal activity has emerged, and a number of studies supported this hypothesis. Moreover, brain energy metabolism was demonstrated to be compartmentalized in neurons and astrocytes, and astrocytic glycolysis was proposed to serve the energetic demands of glutamatergic activity. Shedding light on the role of astrocytes in brain metabolism, the earlier picture of astrocytes being restricted to a scaffold-associated function in the brain is now out of date. With the development and optimization of non-invasive techniques, such as nuclear magnetic resonance spectroscopy (MRS), several groups have worked on assessing cerebral metabolism in vivo. In this context, 1H MRS has allowed the measurements of energy metabolism-related compounds, whose concentrations can vary under different brain activation states. 1H-[13C] MRS, i.e., indirect detection of signals from 13C-coupled 1H, together with infusion of 13C-enriched glucose has provided insights into the coupling between neurotransmission and glucose oxidation. Although these techniques tackle the coupling between neuronal activity and metabolism, they lack chemical specificity and fail in providing information on neuronal and glial metabolic pathways underlying those processes. Currently, the improvement of detection modalities (i.e., direct detection of 13C isotopomers), the progress in building adequate mathematical models along with the increase in magnetic field strength now available render possible detailed compartmentalized metabolic flux characterization. In particular, direct 13C MRS offers more detailed dataset acquisitions and provides information on metabolic interactions between neurons and astrocytes, and their role in supporting neurotransmission. Here, we review state

  10. How Energy Metabolism Supports Cerebral Function: Insights from (13)C Magnetic Resonance Studies In vivo.

    PubMed

    Sonnay, Sarah; Gruetter, Rolf; Duarte, João M N

    2017-01-01

    Cerebral function is associated with exceptionally high metabolic activity, and requires continuous supply of oxygen and nutrients from the blood stream. Since the mid-twentieth century the idea that brain energy metabolism is coupled to neuronal activity has emerged, and a number of studies supported this hypothesis. Moreover, brain energy metabolism was demonstrated to be compartmentalized in neurons and astrocytes, and astrocytic glycolysis was proposed to serve the energetic demands of glutamatergic activity. Shedding light on the role of astrocytes in brain metabolism, the earlier picture of astrocytes being restricted to a scaffold-associated function in the brain is now out of date. With the development and optimization of non-invasive techniques, such as nuclear magnetic resonance spectroscopy (MRS), several groups have worked on assessing cerebral metabolism in vivo. In this context, (1)H MRS has allowed the measurements of energy metabolism-related compounds, whose concentrations can vary under different brain activation states. (1)H-[(13)C] MRS, i.e., indirect detection of signals from (13)C-coupled (1)H, together with infusion of (13)C-enriched glucose has provided insights into the coupling between neurotransmission and glucose oxidation. Although these techniques tackle the coupling between neuronal activity and metabolism, they lack chemical specificity and fail in providing information on neuronal and glial metabolic pathways underlying those processes. Currently, the improvement of detection modalities (i.e., direct detection of (13)C isotopomers), the progress in building adequate mathematical models along with the increase in magnetic field strength now available render possible detailed compartmentalized metabolic flux characterization. In particular, direct (13)C MRS offers more detailed dataset acquisitions and provides information on metabolic interactions between neurons and astrocytes, and their role in supporting neurotransmission. Here

  11. Evaluation of efficacy of transcatheter arterial chemoembolization for hepatocellular carcinoma using magnetic resonance diffusion-weighted imaging

    PubMed Central

    Wu, Xiao-Ming; Wang, Jun-Feng; Ji, Jian-Song; Chen, Ming-Gao; Song, Jian-Gang

    2017-01-01

    Although the efficacy of transcatheter arterial chemoembolization (TACE) has been recommended as first-line therapy for nonsurgical patients with hepatocellular carcinoma (HCC), it is difficult to accurately predict the efficacy of TACE. Therefore, this study evaluated the efficacy of TACE for HCC using magnetic resonance (MR) diffusion-weighted imaging (DWI). A total of 84 HCC patients who received initial TACE were selected and assigned to the stable group (n=39) and the progressive group (n=45). Before TACE treatment, a contrast-enhanced MR scan and DWI (b=300, 600, and 800 s/mm2) were performed on all patients. The modified response evaluation criteria in solid tumors were used for evaluation of tumor response. Receiver operating characteristic curve was employed to predict the value of apparent diffusion coefficient (ADC) for TACE efficacy. The ADC values of HCC patients in the progressive group were higher than those in the stable group at different b-values (b=300, 600, and 800 s/mm2) before TACE treatment. The area under the curve of ADC values with b-values of 300, 600, and 800 s/mm2 were 0.693, 0.724, and 0.746; the threshold values were 1.94×10−3 mm2/s, 1.28×10−3 mm2/s, and 1.20×10−3 mm2/s; the sensitivity values were 55.6%, 77.8%, and 73.3%; and the specificity values were 82.1%, 61.5%, and 71.8%, respectively. Our findings indicate that the ADC values of MR-DWI may accurately predict the efficacy of TACE in the treatment of HCC patients. PMID:28352195

  12. Use of T2-weighted magnetic resonance imaging of the optic nerve sheath to detect raised intracranial pressure

    PubMed Central

    Geeraerts, Thomas; Newcombe, Virginia FJ; Coles, Jonathan P; Abate, Maria Giulia; Perkes, Iain E; Hutchinson, Peter JA; Outtrim, Jo G; Chatfield, Dot A; Menon, David K

    2008-01-01

    Introduction The dural sheath surrounding the optic nerve communicates with the subarachnoid space, and distends when intracranial pressure is elevated. Magnetic resonance imaging (MRI) is often performed in patients at risk for raised intracranial pressure (ICP) and can be used to measure precisely the diameter of optic nerve and its sheath. The objective of this study was to assess the relationship between optic nerve sheath diameter (ONSD), as measured using MRI, and ICP. Methods We conducted a retrospective blinded analysis of brain MRI images in a prospective cohort of 38 patients requiring ICP monitoring after severe traumatic brain injury (TBI), and in 36 healthy volunteers. ONSD was measured on T2-weighted turbo spin-echo fat-suppressed sequence obtained at 3 Tesla MRI. ICP was measured invasively during the MRI scan via a parenchymal sensor in the TBI patients. Results Measurement of ONSD was possible in 95% of cases. The ONSD was significantly greater in TBI patients with raised ICP (>20 mmHg; 6.31 ± 0.50 mm, 19 measures) than in those with ICP of 20 mmHg or less (5.29 ± 0.48 mm, 26 measures; P < 0.0001) or in healthy volunteers (5.08 ± 0.52 mm; P < 0.0001). There was a significant relationship between ONSD and ICP (r = 0.71, P < 0.0001). Enlarged ONSD was a robust predictor of raised ICP (area under the receiver operating characteristic curve = 0.94), with a best cut-off of 5.82 mm, corresponding to a negative predictive value of 92%, and to a value of 100% when ONSD was less than 5.30 mm. Conclusions When brain MRI is indicated, ONSD measurement on images obtained using routine sequences can provide a quantitative estimate of the likelihood of significant intracranial hypertension. PMID:18786243

  13. Topographic distribution and characteristics of normal gastric regional lymph nodes on diffusion-weighted magnetic resonance imaging.

    PubMed

    Mao, Yun; Hedgire, Sandeep S; Liao, Gang; Lv, Fajin; Li, Yongmei; Li, Qi; Wang, Ziwei

    2016-02-01

    Current lack of recognition of normal gastric regional lymph nodes (GRLNs) and inherent defect of morphological imaging limit the accuracy of preoperative nodal (N) staging of gastric cancer. To map the distribution of normal GRLNs and evaluating the characteristics of GRLNs with diffusion-weighted imaging (DWI) in healthy population. Forty-nine enrolled healthy volunteers were divided into two age groups and underwent conventional magnetic resonance imaging (MRI) and DWI examinations. The characteristics of GRLNs in 14 regional stations, including short axis diameter (SD), short-to-long axis diameter ratio (SLR), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC), were recorded and compared between age groups and among different stations. The normal GRLNs were mainly distributed in station 7 in both age groups, followed by stations 3, 8, and 9. The SLR was lower in the young group than in the old group (P = 0.034) while SD, SNR, CNR, and ADC were significantly higher in the young group compared to the old group, P = 0.045, 0.041, 0.037, and 0.042, respectively. SD was different among stations in both age groups (P = 0.002, 0.001), especially bigger in station 8, and the SNRs and CNRs of stations 8 and 9 were relatively high in the old group (P = 0.031, 0.035), while there was no difference in ADC value. Better understanding of the appearances of normal GRLNs on conventional MRI and DWI may help to build more appropriate imaging criteria for GRLN assessment in gastric cancer. © The Foundation Acta Radiologica 2015.

  14. Can diffusion-weighted magnetic resonance imaging of clear cell renal carcinoma predict low from high nuclear grade tumors.

    PubMed

    Parada Villavicencio, Carolina; Mc Carthy, Robert J; Miller, Frank H

    2017-04-01

    To assess the diagnostic performance of the apparent diffusion coefficient (ADC) in predicting the Fuhrman nuclear grading of clear cell renal cell carcinomas (ccRCC). A total of 129 patients who underwent partial and radical nephrectomies with pathology-proven ccRCC were retrospectively evaluated. Histopathological characteristics and nuclear grades were analyzed. In addition, conventional magnetic resonance imaging (MRI) features were assessed in consensus by two radiologists to discriminate nuclear grading. ADC values were obtained from a region of interest (ROI) measurement in the ADC maps calculated from diffusion-weighted imaging (DWI) using b values of 50, 500, and 800 s/mm(2). The threshold values for predicting and differentiating low-grade cancers (Fuhrman I-II) from high grade (Fuhrman III-IV) was obtained using binary logistic regression. The ADC cut-off value for differentiating low- and high-grade tumors was determined using classification analysis. Significant associations (P < 0.001) were found between nuclear grading, conventional MR features, and DWI. Hemorrhage, necrosis, perirenal fat invasion, enhancement homogeneity, and cystic component were identified as independent predictors of tumor grade. High-grade ccRCC had significantly lower mean ADC values compared to low-grade tumors. An ADC cut-off value of 1.6 × 10(-3) mm(2)/s had an optimal predictive percentage of 65.5% for low-grade tumors above this threshold and 81% for high-grade ccRCC below this threshold. Overall predictive accuracy was 70.5%. The addition of ADC values to a model based on MRI conventional features demonstrates increased sensitivity and high specificity improving the distinguishing accuracy between both high-grade and low-grade ccRCC.

  15. A reliability assessment of constrained spherical deconvolution-based diffusion-weighted magnetic resonance imaging in individuals with chronic stroke.

    PubMed

    Snow, Nicholas J; Peters, Sue; Borich, Michael R; Shirzad, Navid; Auriat, Angela M; Hayward, Kathryn S; Boyd, Lara A

    2016-01-15

    Diffusion-weighted magnetic resonance imaging (DW-MRI) is commonly used to assess white matter properties after stroke. Novel work is utilizing constrained spherical deconvolution (CSD) to estimate complex intra-voxel fiber architecture unaccounted for with tensor-based fiber tractography. However, the reliability of CSD-based tractography has not been established in people with chronic stroke. Establishing the reliability of CSD-based DW-MRI in chronic stroke. High-resolution DW-MRI was performed in ten adults with chronic stroke during two separate sessions. Deterministic region of interest-based fiber tractography using CSD was performed by two raters. Mean fractional anisotropy (FA), apparent diffusion coefficient (ADC), tract number, and tract volume were extracted from reconstructed fiber pathways in the corticospinal tract (CST) and superior longitudinal fasciculus (SLF). Callosal fiber pathways connecting the primary motor cortices were also evaluated. Inter-rater and test-retest reliability were determined by intra-class correlation coefficients (ICCs). ICCs revealed excellent reliability for FA and ADC in ipsilesional (0.86-1.00; p<0.05) and contralesio