Science.gov

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. Supporting your child with weight loss

    MedlinePlus

    ... health care provider can set healthy goals for weight-loss and help with monitoring and support. Getting support ... to get the whole family to join a weight-loss plan, even if weight loss is not the ...

  3. 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.

  4. 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

  5. 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. PMID:26801339

  6. 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. PMID:19460663

  7. 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). PMID:27512621

  8. Intelligent Quality Prediction Using Weighted Least Square Support Vector Regression

    NASA Astrophysics Data System (ADS)

    Yu, Yaojun

    A novel quality prediction method with mobile time window is proposed for small-batch producing process based on weighted least squares support vector regression (LS-SVR). The design steps and learning algorithm are also addressed. In the method, weighted LS-SVR is taken as the intelligent kernel, with which the small-batch learning is solved well and the nearer sample is set a larger weight, while the farther is set the smaller weight in the history data. A typical machining process of cutting bearing outer race is carried out and the real measured data are used to contrast experiment. The experimental results demonstrate that the prediction accuracy of the weighted LS-SVR based model is only 20%-30% that of the standard LS-SVR based one in the same condition. It provides a better candidate for quality prediction of small-batch producing process.

  9. Caregiver Preferences regarding Technology's Role in Supporting Adolescent Weight Management

    PubMed Central

    Bianchi-Hayes, Josette M.; Schoenfeld, Elinor R.; Cataldo, Rosa; Huang, Jiayu; Pati, Susmita

    2015-01-01

    Background. Health technology provides a wealth of strategies to address chronic health issues, such as childhood obesity. Few studies have assessed parental preferences regarding use of health technology to support weight management for adolescents. Objective. This study determined caregiver beliefs, attitudes, and practices towards using traditional methods and technology-based health applications to address weight management among overweight adolescents. Methods. Self-administered surveys were distributed to caregivers of children ages 11–18 years in Stony Brook Children's Hospital outpatient offices with a BMI ≥ 85th percentile for age, gender. The data were entered into StudyTrax research platform and analyzed using SAS. Results.  N = 114. Mean BMI z-score = 1.95 ± 0.50. Two-thirds (65.8%) of caregivers preferred a weight management program that includes both traditional and technology components. Most parents rated involvement in program development (68.1%), access to content (72.4%) as very important. Those who believed their child's weight was a problem (p = 0.01) were more likely than other parents to prefer a program that combined both traditional and technology components. Conclusions. Parents' perceptions of their child's weight drove preferences about incorporating technology elements into a weight management program. Future weight management programs should incorporate parental content preferences and be tailored to different age groups. PMID:27347500

  10. 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…

  11. Structural safety assessment under the low temperature of KSTAR superconducting magnet-supporting post

    NASA Astrophysics Data System (ADS)

    Her, N. I.; Sa, J. W.; Cho, S.; Do, C. J.; Choi, C. H.; Kim, B. C.; Im, K. H.; Kyum, M.; Kim, W. C.; Kim, G. H.; Yoo, B. J.; Oh, Y. K.; Kim, D. L.; Kwon, M.; Lee, G. S.; Kstar Team

    2001-01-01

    A magnet-supporting post installed between the lower TF coil cooled by 4.5 K supercritical helium and the cryostat base is one of the most important components of the superconducting magnet-supporting structure for KSTAR Tokamak. This structure should be flexible to absorb thermal shrink of the magnet and should also be rigid to support the magnet weight and the plasma disruption load. The post was designed with stainless steel (SS) 316 LN and carbon fiber reinforced plastic (CFRP) that has low thermal conductivity and high structural strength at low temperature. In order to verify the fabricability and the structural safety, a whole scale prototype of the KSTAR magnet-supporting post was manufactured and tested. Both static and compressive cyclic load tests under the maximum plasma vertical disruption load and the magnet dead weight were performed. The test results showed that the magnet-supporting post of KSTAR Tokamak was fabricable and structurally rigid.

  12. [Diffusion Weighted Magnetic Resonance Imaging and its Application in Ophthalmology].

    PubMed

    Lindner, T; Langner, S; Paul, K; Pohlmann, A; Hadlich, S; Niendorf, T; Jünemann, A; Guthoff, R F; Stachs, O

    2015-12-01

    The value of diffusion-weighted magnet resonance imaging (DWI-MRI) has been demonstrated for an ever growing range of clinical indications. DWI is sensitive to the diffusion of water molecules and probes their random displacement within tissue. DWI provides both qualitative and quantitative information on tissue characteristics, e.g. tissue cellularity. This review provides an overview of diffusion-weighted imaging and its emerging applications in ophthalmology. The basic physics and technical foundations of DWI are introduced. The emerging applications of DWI are surveyed, particularly in diseases of the eye, orbit and optical nerve. PMID:26678901

  13. Efficient magnetic fields for supporting toroidal plasmas

    NASA Astrophysics Data System (ADS)

    Landreman, Matt; Boozer, Allen H.

    2016-03-01

    The magnetic field that supports tokamak and stellarator plasmas must be produced by coils well separated from the plasma. However, the larger the separation, the more difficult it is to produce a given magnetic field in the plasma region, so plasma configurations should be chosen that can be supported as efficiently as possible by distant coils. The efficiency of an externally generated magnetic field is a measure of the field's shaping component magnitude at the plasma compared to the magnitude near the coils; the efficiency of a plasma equilibrium can be measured using the efficiency of the required external shaping field. Counterintuitively, plasma shapes with low curvature and spectral width may have low efficiency, whereas plasma shapes with sharp edges may have high efficiency. Two precise measures of magnetic field efficiency, which correctly identify such differences in difficulty, will be examined. These measures, which can be expressed as matrices, relate the externally produced normal magnetic field on the plasma surface to the either the normal field or current on a distant control surface. A singular value decomposition (SVD) of either matrix yields an efficiency ordered basis for the magnetic field distributions. Calculations are carried out for both tokamak and stellarator cases. For axisymmetric surfaces with circular cross-section, the SVD is calculated analytically, and the range of poloidal and toroidal mode numbers that can be controlled to a given desired level is determined. If formulated properly, these efficiency measures are independent of the coordinates used to parameterize the surfaces.

  14. 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.

  15. Field Balancing of Magnetically Levitated Rotors without Trial Weights

    PubMed Central

    Fang, Jiancheng; Wang, Yingguang; Han, Bangcheng; Zheng, Shiqiang

    2013-01-01

    Unbalance in magnetically levitated rotor (MLR) can cause undesirable synchronous vibrations and lead to the saturation of the magnetic actuator. Dynamic balancing is an important way to solve these problems. However, the traditional balancing methods, using rotor displacement to estimate a rotor's unbalance, requiring several trial-runs, are neither precise nor efficient. This paper presents a new balancing method for an MLR without trial weights. In this method, the rotor is forced to rotate around its geometric axis. The coil currents of magnetic bearing, rather than rotor displacement, are employed to calculate the correction masses. This method provides two benefits when the MLR's rotation axis coincides with the geometric axis: one is that unbalanced centrifugal force/torque equals the synchronous magnetic force/torque, and the other is that the magnetic force is proportional to the control current. These make calculation of the correction masses by measuring coil current with only a single start-up precise. An unbalance compensation control (UCC) method, using a general band-pass filter (GPF) to make the MLR spin around its geometric axis is also discussed. Experimental results show that the novel balancing method can remove more than 92.7% of the rotor unbalance and a balancing accuracy of 0.024 g mm kg−1 is achieved.

  16. 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

  17. 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. PMID:26403857

  18. 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.

  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. Diffusion weighted magnetic resonance imaging and its recent trend—a survey

    PubMed Central

    Chilla, Geetha Soujanya; Tan, Cher Heng

    2015-01-01

    Since its inception in 1985, diffusion weighted magnetic resonance imaging has been evolving and is becoming instrumental in diagnosis and investigation of tissue functions in various organs including brain, cartilage, and liver. Even though brain related pathology and/or investigation remains as the main application, diffusion weighted magnetic resonance imaging (DWI) is becoming a standard in oncology and in several other applications. This review article provides a brief introduction of diffusion weighted magnetic resonance imaging, challenges involved and recent advancements. PMID:26029644

  1. 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...

  2. Brief report: A randomized controlled trial examining peer support and behavioral weight loss treatment.

    PubMed

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

    2015-10-01

    Peer support among adolescents has been positively associated with heath behaviors; however, enhancing peer support for weight loss has rarely been studied among adolescents. This study examined whether a peer support training component delivered to enhance a standard weight loss program led to improved outcomes. Forty-one overweight adolescent females were randomly assigned to a Standard or Enhanced Peer Support intervention. The Enhanced group received in person peer support skills training and practiced skills using social networking. At 16 weeks, participants in the Enhanced condition reported significantly increased perceptions of friend support. Both groups demonstrated significant weight loss (6.4 lbs, ± 8.3). Attendance and self-monitoring were associated with weight loss. Perceptions of peer support can be increased with a peer training component, but did not increase weight loss during the short term. PMID:26265590

  3. Occlusion and weight change in a patient after esophagectomy: success derived from restoration of occlusal support.

    PubMed

    Yamanaka, Reiko; Soga, Yoshihiko; Minakuchi, Mami; Nawachi, Kumiko; Maruyama, Takayuki; Kuboki, Takuo; Morita, Manabu

    2013-01-01

    Occlusal support may be an important factor affecting nutritional support after major surgery. This report presents a patient who gained body weight after receiving a new prosthesis. The patient was an 82-year-old man with thoracic esophageal carcinoma. He did not have occlusal support because of multiple caries lesions. His body weight slowly increased after surgery, but almost stopped in the period of 54 to 68 days after surgery. After treatment with dentures (day 72 postsurgery), body weight gain was observed again, although his medical treatment had not changed. An appropriate prosthesis could contribute to perioperative nutrition support and may lead to earlier recovery after surgery. PMID:24179973

  4. Birth weight, domestic violence, coping, social support, and mental health of young Iranian mothers in Tehran.

    PubMed

    Abadi, Mozhdeh Nasseh Lotf; Ghazinour, Mehdi; Nygren, Lennart; Nojomi, Marzieh; Richter, Jörg

    2013-07-01

    The aim of this study was to investigate associations of birth weight with sociodemographic variables, domestic violence, ways of coping, social support, and general mental health of Iranian mothers. Six hundred mothers aged 15 to 29 years participated between June 2009 and November 2010. t-Test, analysis of variance, Spearman's correlation, and multiple regression were used. The results showed that there was no significant association between birth weight and general mental health of the mothers. Prenatal care visits, the mothers' history of having children with low birth weight (LBW), and weight gain during pregnancy were significantly associated with birth weight. The women who reported physical abuse during pregnancy had infants with lower birth weight. Satisfaction with social support and use of positive reappraisal were significantly associated with higher birth weight. In conclusion, a high quality of prenatal care and screening of pregnant women are recommended. Social environments good enough during pregnancy have protective effects against LBW. PMID:23817159

  5. Benefits of recruiting participants with friends and increasing social support for weight loss and maintenance.

    PubMed

    Wing, R R; Jeffery, R W

    1999-02-01

    To determine the benefits of social support for weight loss and maintenance, this study recruited participants (N = 166) either alone or with 3 friends or family members and then randomly assigned them to a standard behavioral treatment (SBT) or SBT with social support strategies. Participants recruited with friends had greater weight losses at the end of the 4-month treatment and at Month 10 follow-up. Both recruitment strategy and the social support manipulation affected treatment completion and weight-loss maintenance. In those recruited alone and given SBT, 76% completed treatment and 24% maintained their weight loss in full from Months 4 to 10. Among those recruited with friends and given SBT plus social support, 95% completed treatment and 66% maintained their weight loss in full. PMID:10028217

  6. 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.

  7. 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. PMID:25564491

  8. 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

  9. 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…

  10. 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…

  11. 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,…

  12. 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.

  13. Eating behaviors, victimization, and desire for supportive intervention among adolescents in weight-loss camps.

    PubMed

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

    2013-12-01

    This study examined links between eating behaviors, weight-based victimization (WBV) and preferences for bullying intervention among adolescents. Adolescents enrolled in weight loss camps participated in an online survey (N = 361). Regression models examined relationships between key variables. Almost half of adolescents who experienced WBV engaged in unhealthy eating behaviors, which corresponded to less desire for supportive intervention. Unhealthy eating behaviors may offset adaptive coping strategies to deal with WBV, such as support from peers and family. PMID:24183141

  14. 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...

  15. Diffusion-weighted imaging in pediatric body magnetic resonance imaging.

    PubMed

    Chavhan, Govind B; Caro-Dominguez, Pablo

    2016-05-01

    Diffusion-weighted MRI is being increasingly used in pediatric body imaging. Its role is still emerging. It is used for detection of tumors and abscesses, differentiation of benign and malignant tumors, and detection of inflamed bowel segments in inflammatory bowel disease in children. It holds great promise in the assessment of therapy response in body tumors, with apparent diffusion coefficient (ADC) value as a potential biomarker. Significant overlap of ADC values of benign and malignant processes and less reproducibility of ADC measurements are hampering its widespread use in clinical practice. With standardization of the technique, diffusion-weighted imaging (DWI) is likely to be used more frequently in clinical practice. We discuss the principles and technique of DWI, selection of b value, qualitative and quantitative assessment, and current status of DWI in evaluation of disease processes in the pediatric body. PMID:27229502

  16. Body weight support by virtual model control of an impedance controlled exoskeleton (LOPES) for gait training.

    PubMed

    van der Kooij, Herman; Koopman, Bram; van Asseldonk, Edwin H F

    2008-01-01

    The feasibility of an alternative method to support body weight in a powered exoskeleton is demonstrated. Instead of using an overhead suspension system, body weight is supported by augmenting the joint moments through virtual model control. The advantages of this novel method is that it allows for independent support of the left and right leg, and does not interfere with the excitation of cutanous afferents and balance of the body or trunk. Results show that after a short familiarization period the activity of muscles during initial stance reduces and kinematics become close to normal. PMID:19163077

  17. Feature weighting algorithms for classification of hyperspectral images using a support vector machine.

    PubMed

    Qi, Bin; Zhao, Chunhui; Yin, Guisheng

    2014-05-01

    The support vector machine (SVM) is a widely used approach for high-dimensional data classification. Traditionally, SVMs use features from the spectral bands of hyperspectral images with each feature contributing equally to the classification. In practical applications, although affected by noise, slight contributions can also be obtained from deteriorated bands. Thus, compared with feature reduction or equal assignment of weights to all the features, feature weighting is a trade-off choice. In this study, we examined two approaches to assigning weights to SVM features to increase the overall classification accuracy: (1) "CSC-SVM" refers to a support vector machine with compactness and a separation coefficient feature weighting algorithm, and (2) "SE-SVM" refers to a support vector machine with a similarity entropy feature weighting algorithm. Analyses were conducted on a public data set with nine selected land-cover classes. In comparison with traditional SVMs and other classical feature weighting algorithms, the proposed weighting algorithms increase the overall classification accuracy, and even better results could be obtained with few training samples. PMID:24921869

  18. Nonporous magnetic materials as enzyme supports: studies with immobilized chymotrypsin.

    PubMed

    Munro, P A; Dunnill, P; Lilly, M D

    1977-01-01

    Chymotrypsin has been immobilized to several nonporous magnetic materials. Nickel particles were considered to be most suitable as immobilized enzyme supports. Chymotrypsin immobilized to nonporous magnetic supports was not fouled significantly by either whole milk or clarified yeast homogenate. AE-cellulose-chymotrypsin was rapidly fouled by both these materials and chymotrypsin immobilized to acrylic-based ion exchangers was slowly fouled. Immobilized enzyme activity was found to be inversely proportional to particle diameter for nonporous rock magnetic particles. Immobilization by adsorption and then glutaraldehyde crosslinking was used to produce controlled amounts of chymotrypsin on the particles. Esterolytic activity increased with enzyme loading but caseinolytic activity did not increase. Chymotrypsin is inhibited by metal ions from the magnetic supports. It is partially protected by use of a preliminary protein coating and may be reactivated by incubation with EDTA or BSA. PMID:14743

  19. 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

  20. 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

  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. PMID:25979443

  2. 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

  3. 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

  4. 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.

  5. The Effects of an Educational and Supportive Relactation Program on Weight Gain of Preterm Infants

    PubMed Central

    Dehkhoda, Nahid; Valizadeh, Sousan; Jodeiry, Behzad; Hosseini, Mohammad-Bagher

    2013-01-01

    Introduction: Re-establishing breastfeeding (relactation) is necessary in preterm infants who are deprived of breastfeeding due to hospitalized in the neonatal intensive care unit (NICU). Although NICU nurses train mothers about breastfeeding and relactation to some degree, there exists a lack of support or evaluation for restarting breastfeeding. The present study tried to determine the effects of an educational and supportive relactation program on weight gain of preterm infants. Methods: This clinical trial study was performed on 60 preterm infants with mean gestational age of 29 weeks hospitalized in NICU of Alzahra Hospital (Tabriz, Iran). The infants were evaluated in two groups of 30. The mothers of infants in the control group received routine training and support about relactation while the intervention group received routine training as well as the designed educational and supportive relactation program including breast pumping, increasing milk agents and kangaroo mother care. Daily follow-up was conducted by the researcher. All the infants were weighed by a co-researcher. Results: On the 14th day of the study, the mean (SD) weight of infants in the control and intervention groups was 1666.67 (136.08) and 1765.86 (156.96) g, respectively. Conclusion: Providing mothers with support from the medical team and training on relactation and kangaroo mother care can lead to better weight gain of the low birth weight premature infants. PMID:25276715

  6. A filament supported by different magnetic field configurations

    NASA Astrophysics Data System (ADS)

    Guo, Y.; Schmieder, B.; Démoulin, P.; Wiegelmann, T.; Aulanier, G.; Török, T.; Bommier, V.

    2011-08-01

    A nonlinear force-free magnetic field extrapolation of vector magnetogram data obtained by THEMIS/MTR on 2005 May 27 suggests the simultaneous existence of different magnetic configurations within one active region filament: one part of the filament is supported by field line dips within a flux rope, while the other part is located in dips within an arcade structure. Although the axial field chirality (dextral) and the magnetic helicity (negative) are the same along the whole filament, the chiralities of the filament barbs at different sections are opposite, i.e., right-bearing in the flux rope part and left-bearing in the arcade part. This argues against past suggestions that different barb chiralities imply different signs of helicity of the underlying magnetic field. This new finding about the chirality of filaments will be useful to associate eruptive filaments and magnetic cloud using the helicity parameter in the Space Weather Science.

  7. 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

  8. Light weight, high field, stable, superconducting magnets for advanced transportation systems

    SciTech Connect

    Lubell, M.S.; Dresner, L.; Kenney, W.J.; Lue, J.W.; Luton, J.N.; Schwenterly, S.W.

    1991-01-01

    Although the Guideway may be the most expensive component of a MAGLEV system, the importance of a suitable magnet system should not be underestimated. The reliability of operation of MAGLEV depends on the superconducting magnets performing to their specifications in a reliable manner (i.e., without training or quenching). Besides reliability the magnets should produce high field, be sufficiently stable to withstand reasonable perturbations, be light weight, be protected in the event of a quench, and be economical (although performance should outweigh cost). We propose to develop superconducting magnets that have these features. Our magnet designs are based on internally cooled, cable-in-conduit superconductor with Polymer Matrix Composites (PMC) as the structural reinforcement. Although the initial work is with metallic superconductors such as NbTi, the processes being developed will be applicable to the High Temperature Ceramic Superconductors when they become suitable for magnet applications.

  9. Life cycle impact assessment weights to support environmentally preferable purchasing in the United States.

    PubMed

    Gloria, Thomas P; Lippiatt, Barbara C; Cooper, Jennifer

    2007-11-01

    LCA is a quantitative method for understanding the environmental impacts of a product, yet all product purchasing decisions are ultimately subjective. Weights are the nexus between the quantitative results of LCA and the values-based, subjective choices of decision makers. In May 2007, NIST introduced a new optional weight set in Version 4.0 of the BEES software. Three key points about this new optional weight set are the basis for discussion in this paper: The new weight set was created specifically in the context of BEES. It is intended to support a practical method to assist environmentally preferable purchasing in the United States based on LCIA results. This is in contrast to the weight sets currently in BEES, which are based on generalist perspectives. The new weight set was created by a multi-stakeholder panel via the AHP method, and is a synthesis of panelists' perspectives on the relative importance of each environmental impact category in BEES. The weight set draws on each panelist's personal and professional understanding of, and value attributed to, each impact category. While the synthesized weight set may not equally satisfy each panelist's view of impact importance, it does reflect contemporary values in applying LCAto real world decisions, and represents one approach others can learn from in producing weight sets. The new weight set offers BEES users an additional option for synthesizing and comparing the environmental performance of building products and making purchasing decisions. In so doing, it strengthens the decision-making process, which is important when making product comparisons in the public domain. The Weight Set: Across all panelists and with explicit consideration of all time horizons, anthropogenic contributions to global warming, weighted at 29%, was judged most important, yet not so important that decisions can be made solely on the basis of this impact. A strong tail of other concerns include fossil fuel depletion (10%), criteria

  10. 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

  11. 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. PMID:25990210

  12. 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…

  13. 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.

  14. 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.

  15. 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. PMID:26863465

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:25554293

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

    NASA Astrophysics Data System (ADS)

    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.

  2. 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.

  3. Differential effects of low versus high amounts of weight supported treadmill training in spinally transected rats.

    PubMed

    de Leon, Ray D; See, Pamela A; Chow, Cheryl H T

    2011-06-01

    Intensive weight-supported treadmill training (WSTT) improves locomotor function following spinal cord injury. Because of a number of factors, undergoing intensive sessions of training may not be feasible. Whether reduced amounts of training are sufficient to enhance spinal plasticity to a level that is necessary for improving function is not known. The focus of the present study was to assess differences in recovery of locomotor function and spinal plasticity as a function of the amount of steps taken during WSTT in a rodent model of spinal cord injury. Rats were spinally transected at 5 days of age. When they reached 28 days of age, a robotic system was used to implement a weight-supported treadmill training program of either 100 or 1000 steps/training session daily for 4 weeks. Antibodies for brain-derived neurotrophic factor (BDNF), TrkB, and the pre-synaptic marker, synaptophysin, were used to examine the expression of these proteins in the ventral horn of the lumbar spinal cord. Rats that received weight-supported treadmill training performed better stepping relative to untrained rats, but only the rats that received 1000 steps/training session recovered locomotor function that resembled normal patterns. Only the rats that received 1000 steps/training session recovered normal levels of synaptophysin immunoreactivity around motor neurons. Weight-supported treadmill training consisting of either 100 or 1000 steps/training session increased BDNF immunoreactivity in the ventral horn of the lumbar spinal cord. TrkB expression in the ventral horn was not affected by spinal cord transection or weight-supported treadmill training. Synaptophysin expression, but not BDNF or TrkB expression was correlated with the recovery of stepping function. These findings suggested that a large amount of weight-supported treadmill training was necessary for restoring synaptic connections to motor neurons within the locomotor generating circuitry. Although a large amount of training

  4. myPace: an integrative health platform for supporting weight loss and maintenance behaviors.

    PubMed

    Barnett, Julie; Harricharan, Michelle; Fletcher, Dave; Gilchrist, Becky; Coughlan, Jane

    2015-01-01

    Obesity is a major health concern caused by unhealthy eating behaviors. Digital weight loss interventions have adopted mobile technology primarily in order to support self-monitoring. However, many available apps are not designed as a part of dietetic practice; therefore, a distinct gap in the research exists relating to technology that supports the patient-practitioner relationship. This paper presents myPace, which is a complete weight loss and management system that is deployed via a smartphone and a PC. It connects dietitians and patients between face-to-face consultations and extends the relationship through patients' regular progress updates and dietitians' tailored and timely advice, for sustained behavior change. The prototype was developed from research into behavior change for weight loss, which furthermore was underpinned by theory and tenets of human support models, such as the supportive accountability framework. We report on an early-phase system design goals via a formative research process, which aimed to implement theoretical principles and match practical dietetic practice. To that end, only the clinical end user's perspective was sought through a coaching think-aloud protocol on the first iteration of the prototype and interviews with dietitians. Findings show that the system has many positive design features, but which require further development in order for the system to be fully acceptable within dietetic practice and motivate patient engagement. PMID:25438329

  5. 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. PMID:22941943

  6. Assessment Method of Harmonic Emission Level Based on the Improved Weighted Support Vector Machine Regression

    NASA Astrophysics Data System (ADS)

    Jiang, Wei-Zhong; Su, Ning; Ding, Li-Ping; Qiu, Si-Yu

    This paper presents a new method to estimate the system harmonic impedance and the harmonic emission level based on the improved weighted support vector machine (WSVM) regression. According to the differences of harmonic measurement data at the point of common coupling, the WSVM can be obtained by correcting the error requirement of SVM by Euclidean distance as a weighted index and determining the weighted coefficient of penalty parameter by linear interpolation, then the system harmonic impedance and the harmonic emission level can be calculated. Based on analyzing the simulation of the circuit and the practical application of field data, it proves that the proposed method can effectively restrain the influence caused by the fluctuation of background harmonic on estimation results. Compared with other methods, the estimate result of the proposed method is more reasonable.

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

    PubMed

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

    2012-04-01

    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 nonparametric 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 vs. family support could inform future targeted weight-loss interventions to subgroups at risk. PMID:21996661

  8. 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.

  9. 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

  10. 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

  11. SUSCEPTIBILITY ARTIFACTS ON T2*-WEIGHTED MAGNETIC RESONANCE IMAGING OF THE CANINE AND FELINE SPINE.

    PubMed

    Hammond, Laura J; Hecht, Silke

    2015-01-01

    The T2*-weighted gradient recalled echo sequence is a sensitive means to detect blood degradation products. While not a routine sequence in magnetic resonance imaging of the spine in small animals, it can provide additional valuable information in select cases. The goal of this retrospective, cross-sectional study was to describe findings when acquiring this sequence during magnetic resonance imaging examination of the spine in small animals. The University of Tennessee's veterinary radiology database was searched for dogs and cats that underwent magnetic resonance imaging for suspect spinal disease in which a T2*-weighted gradient recalled echo sequence was acquired and susceptibility artifact was identified. The following information was recorded: signalment, clinical signs, location and appearance of susceptibility artifact, and final diagnosis. Thirty-nine cases were included in the study. Extradural susceptibility artifacts were observed in cases of intervertebral disc herniation with or without associated hemorrhage (n = 28), extradural hemorrhage associated with spinal trauma (n = 2), hemophilia (n = 1), and in a cystic extradural mass (n = 1). Remaining lesions displaying susceptibility artifact were intramedullary and included presumptive acute noncompressive nucleus pulposus extrusion (n = 2), hematoma (n = 1), hemangiosarcoma metastasis (n = 1), intramedullary disc extrusion (n = 1), presumptive meningomyelitis (n = 1), and a mass of undetermined etiology (n = 1). Inclusion of a T2*-weighted gradient recalled echo sequence may be helpful in spinal magnetic resonance imaging when standard imaging sequences are ambiguous or intramedullary lesions are observed. PMID:25693447

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Magnetic properties prediction of NdFeB magnets by using support vector regression

    NASA Astrophysics Data System (ADS)

    Cheng, Wende

    2014-09-01

    A novel model using support vector regression (SVR) combined with particle swarm optimization (PSO) was employed to construct mathematical model for prediction of the magnetic properties of the NdFeB magnets. The leave-one-out cross-validation (LOOCV) test results strongly supports that the generalization ability of SVR is high enough. Predicted results show that the mean absolute percentage error for magnetic remanence Br, coercivity Hcj and maximum magnetic energy product (BH)max are 0.53%, 3.90%, 1.73%, and the correlation coefficient (R2) is as high as 0.839, 0.967 and 0.940, respectively. This investigation suggests that the PSO-SVR is not only an effective and practical method to simulate the properties of NdFeB, but also a powerful tool to optimatize designing or controlling the experimental process.

  17. 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.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Diffusion-weighted magnetic resonance imaging in tubo-ovarian abscess: a case report.

    PubMed

    Takeshita, Tohru; Ninoi, Teruhisa; Doh, Kunihiko; Hashimoto, Shigeo; Inoue, Yuichi

    2009-12-01

    In this report, we describe the magnetic resonance imaging appearance of tubo-ovarian abscess (TOA) in a patient who underwent diffusion-weighted imaging (DWI) of the pelvis and subsequent histologic analysis. The content of the TOA was markedly high signal intensity relative to the surrounding tissue on DWI, and it showed low signal intensity on the apparent diffusion coefficient map; these findings were consistent with those of published reports on brain and liver abscesses. PMID:20088410

  2. 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

  3. Focal liver lesions hyperintense on T1-weighted magnetic resonance images.

    PubMed

    Furlan, Alessandro; Marin, Daniele; Bae, Kyongtae T; Lagalla, Roberto; Agnello, Francesco; Bazzocchi, Massimo; Brancatelli, Giuseppe

    2009-10-01

    This article reviews focal liver lesions hyperintense on T1-weighted magnetic resonance (MR) images and describes the underlying etiologies associated with their T1 signal intensity. Although focal liver lesions are commonly detected because of their iso- or hypointensity on T1-weighted images, lesions (benign or malignant) may present with T1 hyperintensity when they contain T1 shortening elements--such as fat, hemorrhage, copper, melanin, and highly concentrated proteins. Our discussion includes the description of state-of-the-art T1-weighted MR sequences and the imaging features of lesions on pre- and postcontrast MR images that are characteristic for lesion composition and useful for making accurate diagnosis. PMID:19842568

  4. 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.

  5. THERMAL EQUILIBRIA OF MAGNETICALLY SUPPORTED BLACK HOLE ACCRETION DISKS

    SciTech Connect

    Oda, H.; Machida, M.; Nakamura, K. E.; Matsumoto, R.

    2009-05-20

    We present new thermal equilibrium solutions for optically thin and optically thick disks incorporating magnetic fields. The purpose of this paper is to explain the bright hard state and the bright/slow transition observed in the rising phases of outbursts in black hole candidates. On the basis of the results of three-dimensional magnetohydrodynamic simulations, we assume that magnetic fields inside the disk are turbulent and dominated by the azimuthal component and that the azimuthally averaged Maxwell stress is proportional to the total (gas, radiation, and magnetic) pressure. We prescribe the magnetic flux advection rate to determine the azimuthal magnetic flux at a given radius. Local thermal equilibrium solutions are obtained by equating the heating, radiative cooling, and heat advection terms. We find magnetically supported ({beta} = (p {sub gas} + p {sub rad})/p {sub mag} < 1), thermally stable solutions for both optically thin disks and optically thick disks, in which the heating enhanced by the strong magnetic field balances the radiative cooling. The temperature in a low-{beta} disk (T {approx} 10{sup 7}-10{sup 11}K) is lower than that in an advection-dominated accretion flow (or radiatively inefficient accretion flow) but higher than that in a standard disk. We also study the radial dependence of the thermal equilibrium solutions. The optically thin, low-{beta} branch extends to M-dot{approx}>0.1 M-dot{sub Edd}, where M-dot is the mass accretion rate and M-dot{sub Edd} is the Eddington mass accretion rate, in which the temperature anticorrelates with the mass accretion rate. Thus, optically thin low-{beta} disks can explain the bright hard state. Optically thick, low-{beta} disks have the radial dependence of the effective temperature T {sub eff} {proportional_to} piv{sup -3/4}. Such disks will be observed as staying in a high/soft state. Furthermore, limit cycle oscillations between an optically thick low-{beta} disk and a slim disk will occur because

  6. Metal Matrix Superconductor Composites for Flight-Weight Microwave Lightcraft Magnets

    SciTech Connect

    Gross, Dan A.; Myrabo, Leik N.

    2008-04-28

    Flight-weight superconducting magnets are designed for a 20-m diameter MicroWave LightCraft (MWLC). The twin coil unit with storage capacity of 900 MJ, is made of structural carbon fiber filaments with a superconducting MgCNi{sub 3} high current density film surface layer, imbedded in a beryllium stabilizer matrix of high electrical and thermal conductivity. These 'bucking' magnets run circumferentially about the lightcraft rim, and provide a 2-Tesla magnetic field necessary for the craft's hypersonic MHD slipstream accelerator. Each magnet is comprised of a single 22 cm diameter, hollow cylindrical cable made from metal matrix composites for superconductors (MMC lowbar Sc) with integral coolant passageways for circulating liquid-helium coolant to prevent the magnets from warming above the superconductive transition temperature. Each is suspended inside a 30-cm diameter toroidal vacuum tube, braced by a radial mesh of high-strength insulating fibers loaded in tension. For a coil separation distance of 1.4 m, each coil has a calculated mass of 1365 kg which is within 2x of the ultimate objective.

  7. Metal Matrix Superconductor Composites for Flight-Weight Microwave Lightcraft Magnets

    NASA Astrophysics Data System (ADS)

    Gross, Dan A.; Myrabo, Leik N.

    2008-04-01

    Flight-weight superconducting magnets are designed for a 20-m diameter MicroWave LightCraft (MWLC). The twin coil unit with storage capacity of 900 MJ, is made of structural carbon fiber filaments with a superconducting MgCNi3 high current density film surface layer, imbedded in a beryllium stabilizer matrix of high electrical and thermal conductivity. These "bucking" magnets run circumferentially about the lightcraft rim, and provide a 2-Tesla magnetic field necessary for the craft's hypersonic MHD slipstream accelerator. Each magnet is comprised of a single 22 cm diameter, hollow cylindrical cable made from metal matrix composites for superconductors (MMC_Sc) with integral coolant passageways for circulating liquid-helium coolant to prevent the magnets from warming above the superconductive transition temperature. Each is suspended inside a 30-cm diameter toroidal vacuum tube, braced by a radial mesh of high-strength insulating fibers loaded in tension. For a coil separation distance of 1.4 m, each coil has a calculated mass of 1365 kg which is within 2x of the ultimate objective.

  8. 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.

  9. Imaging hypothalamic activity using diffusion weighted magnetic resonance imaging in the mouse and human brain.

    PubMed

    Lizarbe, Blanca; Benítez, Ania; Sánchez-Montañés, Manuel; Lago-Fernández, Luis F; Garcia-Martin, María L; López-Larrubia, Pilar; Cerdán, Sebastián

    2013-01-01

    Hypothalamic appetite regulation is a vital homeostatic process underlying global energy balance in animals and humans, its disturbances resulting in feeding disorders with high morbidity and mortality. The objective evaluation of appetite remains difficult, very often restricted to indirect measurements of food intake and body weight. We report here, the direct, non-invasive visualization of hypothalamic activation by fasting using diffusion weighted magnetic resonance imaging, in the mouse brain as well as in a preliminary study in the human brain. The brain of fed or fasted mice or humans were imaged at 7 or 1.5 Tesla, respectively, by diffusion weighted magnetic resonance imaging using a complete range of b values (10weighted image data sets were registered and analyzed pixel by pixel using a biexponential model of diffusion, or a model-free Linear Discriminant Analysis approach. Biexponential fittings revealed statistically significant increases in the slow diffusion parameters of the model, consistent with a neurocellular swelling response in the fasted hypothalamus. Increased resolution approaches allowed the detection of increases in the diffusion parameters within the Arcuate Nucleus, Ventromedial Nucleus and Dorsomedial Nucleus. Independently, Linear Discriminant Analysis was able to classify successfully the diffusion data sets from mice and humans between fed and fasted states. Present results are consistent with increased glutamatergic neurotransmission during orexigenic firing, a process resulting in increased ionic accumulation and concomitant osmotic neurocellular swelling. This swelling response is spatially extendable through surrounding astrocytic networks until it becomes MRI detectable. Present findings open new avenues for the direct, non-invasive, evaluation of appetite disorders and other hypothalamic pathologies helping potentially in the development of the corresponding therapies. PMID:23000787

  10. Diffusion-weighted magnetic resonance imaging findings in a patient with struma ovarii.

    PubMed

    Takeshita, Tohru; Ninoi, Teruhisa; Maebayashi, Tetunori; Doh, Kunihiko; Hashimoto, Shigeo; Mniki, Yumo

    2014-06-01

    In this report, the magnetic resonance imaging (MRI) appearance of struma ovarii (SO) in a patient who underwent diffusion-weighted imaging (DWI) of the pelvis and subsequent histological analysis is described. The solid portion of SO showed a high apparent diffusion coefficient (ADC) value, indicating unrestricted diffusion, and each loculus of SO showed different ADC values due to the different viscosity of the cyst contents in each loculus. These unique and characteristic DWI findings may serve as a helpful sign in making the correct diagnosis of SO when DWI findings are interpreted in conjunction with conventional MRI findings. PMID:25272567

  11. Texture features on T2-weighted magnetic resonance imaging: new potential biomarkers for prostate cancer aggressiveness

    NASA Astrophysics Data System (ADS)

    Vignati, A.; Mazzetti, S.; Giannini, V.; Russo, F.; Bollito, E.; Porpiglia, F.; Stasi, M.; Regge, D.

    2015-04-01

    To explore contrast (C) and homogeneity (H) gray-level co-occurrence matrix texture features on T2-weighted (T2w) Magnetic Resonance (MR) images and apparent diffusion coefficient (ADC) maps for predicting prostate cancer (PCa) aggressiveness, and to compare them with traditional ADC metrics for differentiating low- from intermediate/high-grade PCas. The local Ethics Committee approved this prospective study of 93 patients (median age, 65 years), who underwent 1.5 T multiparametric endorectal MR imaging before prostatectomy. Clinically significant (volume ≥0.5 ml) peripheral tumours were outlined on histological sections, contoured on T2w and ADC images, and their pathological Gleason Score (pGS) was recorded. C, H, and traditional ADC metrics (mean, median, 10th and 25th percentile) were calculated on the largest lesion slice, and correlated with the pGS through the Spearman correlation coefficient. The area under the receiver operating characteristic curve (AUC) assessed how parameters differentiate pGS = 6 from pGS ≥ 7. The dataset included 49 clinically significant PCas with a balanced distribution of pGS. The Spearman ρ and AUC values on ADC were: -0.489, 0.823 (mean) -0.522, 0.821 (median) -0.569, 0.854 (10th percentile) -0.556, 0.854 (25th percentile) -0.386, 0.871 (C); 0.533, 0.923 (H); while on T2w they were: -0.654, 0.945 (C); 0.645, 0.962 (H). AUC of H on ADC and T2w, and C on T2w were significantly higher than that of the mean ADC (p = 0.05). H and C calculated on T2w images outperform ADC parameters in correlating with pGS and differentiating low- from intermediate/high-risk PCas, supporting the role of T2w MR imaging in assessing PCa biological aggressiveness.

  12. 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

  13. Body Weight Support Treadmill Training for Children With Developmental Delay Who Are Ambulatory

    PubMed Central

    Lowe, Leah; McMillan, Amy Gross; Yates, Charlotte

    2015-01-01

    Purpose To examine the effect of body weight supported treadmill training (BWSTT) on gait and gross motor skill development in children (2–5 years old) with developmental delay who are ambulatory. Methods Twenty-four subjects (12 control, 12 BWSTT) were enrolled in this randomized control trial. All subjects continued to receive physical therapy. Subjects were tested at baseline, 4 weeks, 6 weeks, and at 6 weeks following completion of BWSTT. Outcomes were assessed using the 10 Meter Walk Test (10MWT) and Gross Motor Function Measure- D and E. Results Significant improvements were seen in gait velocity and gross motor skill attainment. With positive interactions in both the 10MWT and GMFM-E, the BWSTT group as compared to the control group demonstrated functional gains in gait velocity and gross motor skills, P = .033 and.017, respectively. Conclusions A 6-week high intensity BWSTT program can improve gait velocity and influence functional gains. PMID:26397083

  14. Experimental active structural acoustic control of simply supported plates using a weighted sum of spatial gradients.

    PubMed

    Hendricks, Daniel R; Johnson, William R; Sommerfeldt, Scott D; Blotter, Jonathan D

    2014-11-01

    A limitation currently facing active structural acoustic control (ASAC) researchers is that an ideal minimization quantity for use in the control algorithms has not been developed. A novel parameter termed the "weighted sum of spatial gradients" (WSSG) was recently developed for use in ASAC and shown to effectively attenuate acoustic radiation from a vibrating flat simply supported plate in computer simulations. This paper extends this research from computer simulations and provides experimental test results. The results presented show that WSSG is a viable control quantity and provides better results than the volume velocity approach. The paper also investigates several of the challenges presented by the use of WSSG. These include determining a method to measure WSSG experimentally, an analysis of the influence of noise on WSSG control results and complications presented when degenerate modes exist. Results are shown and discussed for several experimental configurations. PMID:25373961

  15. Incidence and Predictors of Catheterization-Related Cerebral Infarction on Diffusion-Weighted Magnetic Resonance Imaging

    PubMed Central

    Okano, Mitsumasa; Suu, Kanae; Kimura, Masahiro; Minamino-Muta, Eri; Nakane, Eisaku; Izumi, Toshiaki; Miyamoto, Shoichi; Haruna, Tetsuya; Ueyama, Koji

    2016-01-01

    Introduction. The aim of this study was to examine the incidence and risk factors of catheterization-related CI in the contemporary era, using diffusion-weighted magnetic resonance imaging. Methods. We retrospectively analyzed consecutive 84 patients who underwent MRI (magnetic resonance imaging) after 2.81 ± 2.4 days (mean ± SD) of catheterization via aortic arch. We categorized the patients by the presence or absence of acute CI determined by diffusion-weighted MRI and analyzed the incidence and predictors. Results. Of 84 patients that underwent MRI after catheterization, acute CI was determined in 27 (32.1%) patients. In univariate analysis, dyslipidemia, age, coronary artery disease, antiplatelet agents, number of catheters used, urgent settings, and interventional procedures were significantly different. Multivariate analysis revealed dyslipidemia (odds ratio [OR], 4.46; 95% confidence interval [CI], 1.41–16.03; p = 0.01), higher age (OR, 1.09; 95% CI, 1.007–1.19; p = 0.03), and the number of catheters used (OR, 2.21; 95% CI, 1.21–4.36; p = 0.01) as independent predictors of the incidence of catheterization-related acute CI. Conclusions. Dyslipidemia, higher age, and number of catheters used were independent predictors for acute CI after catheterization. These findings imply that managing dyslipidemia and comprehensive planning to minimize the numbers of catheters are important. PMID:27127790

  16. Heavily T2-Weighted Magnetic Resonance Landmarks of the Cavernous Sinus and Paracavernous Region

    PubMed Central

    Hermann, M.; Bobek-Billewicz, B.; Sloniewski, P.

    2000-01-01

    The purpose of this study was to evaluate the magnetic resonance anatomy of the cavernous sinus. Heavily T2-weighted submillimetric sequence in sagittal, coronal, and axial planes was performed in 16 healthy patients. The sequence provides high contrast between fluid and other structures of the cavernous sinus. High signal intensity of the venous spaces of the cavernous sinus provides a kind of a background for internal carotid artery, cranial nerves, and meninges, as well as bony and fibrous structures. The study was performed with the help of an anatomic atlas. Different magnetic resonance (MR) landmarks of the cavernous and parasellar region were introduced and demonstrated. MR images, superior to computer tomography, allow a detailed assessment of the cavernous sinus anatomy. Delineation by magnetic resonance of tiny anatomical structures may help the neurosurgeon trace the exact outline of a tumor and help to plan an adequate strategy if complete resection is attempted. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 8 PMID:17171105

  17. Apolipoprotein E polymorphism and acute ischemic stroke: a diffusion- and perfusion-weighted magnetic resonance imaging study.

    PubMed

    Liu, Yawu; Laakso, Mikko P; Karonen, Jari O; Vanninen, Ritva L; Nuutinen, Juho; Soimakallio, Seppo; Aronen, Hannu J

    2002-11-01

    Diffusion- and perfusion-weighted magnetic resonance imaging (MRI) was used to study the putative effects of apolipoprotein E (ApoE) polymorphism in stroke. Thirty-one patients with acute stroke, comparative for age and gender were scanned, nine of whom were ApoE allele epsilon 4 carriers. Initially, less than 24 hours from the onset of stroke, the epsilon 4 carriers had significantly smaller volumes of hypoperfusion on relative cerebral blood volume map (P = 0.001), and smaller infarct volumes (P = 0.008) compared with the noncarriers. By day 8, this difference in the infarct volumes had disappeared, suggesting relatively enhanced infarct growth. On average, the total infarct volume increased 145% of the initial infarct volume in the epsilon 4 carriers, and 84% in the noncarriers. There were strong correlations between the imaging findings and clinical status initially and with the outcome 3 months after the stroke in the epsilon 4 noncarriers, but, with a single exception at acute phase, a lack thereof in the epsilon 4 carriers. These patterns were virtually similar in a subgroup of patients with middle cerebral artery stroke. These data support the hypothesis of increased general vulnerability of the brain in the epsilon 4 carriers. Thus, the effects of ApoE polymorphism should be accounted for when interpreting diffusion- and perfusion-weighted MRI studies, particularly if predicting lesion growth. PMID:12439291

  18. Use of partial body-weight support for aggressive return to running after lumbar disk herniation: a case report.

    PubMed

    Moore, Melita N; Vandenakker-Albanese, Carol; Hoffman, Martin D

    2010-05-01

    This case report demonstrates the application of partial body-weight supported treadmill running in an aggressive rehabilitation program of an ultramarathon runner who had sustained a lumbar disk herniation. Body-weight supported exercise has recognized value during rehabilitation of lower-extremity injuries. In this case we found that the reductions in vertical loading forces achieved through partial body-weight support can also be valuable in the rehabilitation of an injury above the level of support. This motivated runner successfully used weight-supported treadmill training within 1 week of an acute lumbar disk herniation when he was experiencing considerable pain with unsupported walking and lower-extremity weakness. He continued its use until he adequately improved to allow return to his regular overground running program. This case demonstrates how partial body-weight support can allow aggressive running training early after a lumbar disk injury when normal impact forces cannot be tolerated and when leg weakness is a limitation. PMID:20434621

  19. Diffusion Weighted Magnetic Resonance Imaging for the Characterization of Solitary Pulmonary Lesions

    PubMed Central

    Çakır, Çağlayan; Gençhellaç, Hakan; Temizöz, Osman; Polat, Ahmet; Şengül, Ersin; Duygulu, Gökhan

    2015-01-01

    Background: We evaluated the differential diagnosis of solitary pulmonary lesions on magnetic resonance imaging. Aims: To investigate the value of diffusion weighted imaging on the differential diagnosis of solitary pulmonary lesions. Study Design: Randomized prospective study. Methods: This prospective study included 48 solitary pulmonary nodules and masses (18 benign, 30 malignant). Single shot echo planar spin echo diffusion weighted imaging (DWI) was performed with two b factors (0 and 1000 s/mm2). Apparent diffusion coefficients (ADCs) were calculated. On diffusion weighted (DW) trace images, the signal intensities (SI) of the lesions were visually compared to the SI of the thoracic spinal cord using a 5-point scale: 1: hypointense, 2: moderately hypointense, 3: isointense, 4: moderately hyperintense, 5: significantly hyperintense. For the quantitative evaluation, the lesion to thoracic spinal signal intensity ratios and the ADCs of the lesions were compared between groups. Results: On visual evaluation, taking the density of the spinal cord as a reference, most benign lesions were found to be hypointense, while most of the malignant lesions were evaluated as hyperintense on DWI with a b factor of 1000 s/mm2. In contrast, on T2 weighted images, it was seen that the distinction of malignant lesions from benign lesions was not statistically significant. The ADCs of the malignant lesions were significantly lower than those of benign lesions (mean ADC was 2.02×10−3 mm2/s for malignant lesions, and 1.195×10−3±0.3 mm2/s for benign lesions). Setting the cut-off value at 1.5×10−3, ADC had a sensitivity of 86.7% and a specificity of 88.9% for the differentiation of benign lesions from malignant lesions. Conclusion: DWI may aid in the differential diagnosis of solitary pulmonary lesions. (ClinicalTrials.gov Identifier: NCT02482181) PMID:26740901

  20. 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

  1. Design and analysis of large spaceborne light-weighted primary mirror and its support system

    NASA Astrophysics Data System (ADS)

    Yan, Yong; Jin, Guang; Yang, Hong-bo

    2007-12-01

    With the development of the resolution of spaceborne remote sensor, the diameter of the primary mirror of spaceborne telescope becomes larger and larger. The distortion of primary mirror which is influenced by the mirror material, structure, self-weight, support system and temperature environment affects optical image quality finally. In this paper, an on-axis TMA high-resolution Cassegrain optical payload with a primary mirror whose diameter is φ 650mm was designed and the effects of the influence factors of the distortion acts on the on-axis TMA optical system primary mirror had been analyzed by means of Finite Element Analysis. During work, the technology of the primary mirror design had been summarized and general consideration of the primary mirror design technology also had been described at the same time. Considering the telescope manufacture and work station, a reasonable and optimal structure of the primary mirror sub-assembly is taken finally. In the end, the distortion of the primary mirror during its fabrication station and work station had been analyzed by integrated Finite Element Analysis Method. The results implicated the synthesis profile error (P-V value) for the primary mirror is less than λ/10 and all the indexes of the primary mirror satisfy the requirements of the optical system.

  2. The Effect of Body Weight Support on Kinetics and Kinematics of a Repetitive Plyometric Task.

    PubMed

    Elias, Audrey R; Hammill, Curt D; Mizner, Ryan L

    2016-02-01

    Though essential to athletic performance, the ability to land from a jump often remains limited following injury. While recommended, jump training is difficult to include in rehabilitation programs due to high impact forces. Body weight support (BWS) is frequently used in rehabilitation of gait following neurological and orthopedic injury, and may also allow improved rehabilitation of high-impact tasks. There is a differential effect of BWS on walking and running gaits, and the effect of BWS on movements with relatively large vertical displacement is unknown. The current study evaluates the effect of BWS on a replicable single-leg hopping task. We posited that progressive BWS would decrease limb loading while maintaining the joint kinematics of the task. Twenty-eight participants repetitively hopped on and off a box at each of four BWS levels. Peak vertical ground reaction forces decreased by 22.5% between 0% and 30% BWS (P < .001). Average hip, knee, and ankle internal moments decreased by 0.5 N·m/kg each. Slight kinematic changes across BWS levels were clinically insignificant. The high level of task specificity evidenced by consistent kinematics coupled with a similar reduction of internal moment at each joint suggests that BWS may be a useful strategy for rehabilitation of jumping tasks. PMID:26398961

  3. Diffusion-weighted intensity magnetic resonance in the preoperative diagnosis of cholesteatoma.

    PubMed

    Cavaliere, Michele; Di Lullo, Antonella Miriam; Caruso, Antonia; Caliendo, Giandomenico; Elefante, Andrea; Brunetti, Arturo; Iengo, Maurizio

    2014-01-01

    We have analyzed the preoperative diagnosis of cholesteatoma through the use of diffusion-weighted intensity magnetic resonance (DWI-MR) in 16 consecutive patients suffering from chronic otitis media with clinical and radiological (by computed tomography) suspicion of cholesteatoma. In particular, we compared the radiological data with intraoperative ones, verifying the correspondence (in terms of sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy) between what is reported by DWI-MR and what is actually detectable at the time of surgery. Furthermore, we identified the most reliable DWI-MR sequence [single-shot (SSh) echo planar imaging (EPI) vs. multi-shot turbo spin-echo not-EPI] to detect cholesteatoma and reduce the time for examination. The obtained data on computed tomography scans revealed low diagnostic accuracy (56%); DWI-MR, instead, showed higher values, especially using not-EPI sequences (93.75 vs. 68.75% obtained by SSh-EPI sequences). PMID:25322773

  4. 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

  5. [Ovarian metastases from ventricular cancer diagnosed using diffusion-weighted 3T magnetic resonance imaging].

    PubMed

    Røhl, Lisbeth; Nellemann, Hanne Marie; Ladekarl, Morten; Pedersen, Erik Morre

    2011-04-18

    A 58-year-old female with a non-resectable ventricular cancer was followed by conventional 3.0 T magnetic resonance imaging (MRI) of the pelvis and abdomen including diffusion-weighted MR imaging (DWI). B-values were 0 and 1,000 seconds/mm2, and the apparent diffusion coefficient was calculated. At one control, ovarian metastases were detected by DWI, but did not show on conventional T2 and T1. The ovarian metastases were surgically removed and histologically verified - even though metastasectomy is controversial. In conclusion, DWI at 3.0 T is feasible and can improve the detection of metastatic disease compared with conventional MRI. PMID:21501566

  6. Abdominal applications of diffusion-weighted magnetic resonance imaging: Where do we stand

    PubMed Central

    Morani, Ajaykumar C; Elsayes, Khaled M; Liu, Peter S; Weadock, William J; Szklaruk, Janio; Dillman, Jonathan Russell; Khan, Asra; Chenevert, Thomas L; Hussain, Hero K

    2013-01-01

    Diffusion-weighted imaging (DWI) is one of the magnetic resonance imaging (MRI) sequences providing qualitative as well as quantitative information at a cellular level. It has been widely used for various applications in the central nervous system. Over the past decade, various extracranial applications of DWI have been increasingly explored, as it may detect changes even before signal alterations or morphological abnormalities become apparent on other pulse sequences. Initial results from abdominal MRI applications are promising, particularly in oncological settings and for the detection of abscesses. The purpose of this article is to describe the clinically relevant basic concepts of DWI, techniques to perform abdominal DWI, its analysis and applications in abdominal visceral MR imaging, in addition to a brief overview of whole body DWI MRI. PMID:23671743

  7. Diffusion-weighted magnetic resonance imaging in predicting the radiosensitivity of cervical cancer

    PubMed Central

    Ni, Xiaolei; Tong, Yuanhe; Xiao, Youping; Liao, Jiang; Chen, Yunbing; Wang, Min

    2015-01-01

    This study investigates the application value of diffusion-weighted magnetic resonance imaging in predicting cervical cancer radiosensitivity. Twenty-five patients who were newly diagnosed as cervical cancer and accepted simple radiotherapy were included in this study. Before external irradiation, 20 GY and at the end of irradiation, routine 1.5 T MRI and diffusion-weighted magnetic resonance imaging scanning were carried. Apparent diffusion coefficient (ADC) value of primary tumor was measured. Its correlation with tumor regression rate was analyzed. ADC values of before irradiation, 20 GY and at the end of irradiation was (0.93 ± 0.14) × 10-3 mm2/s, (1.25 ± 0.17) × 10-3 mm2/s and (1.55 ± 0.13) × 10-3 mm2/s, respectively. There were statistical significant differences (P< 0.01). D-value of ADC values between before and 20 GY external irradiation was (0.33 ± 0.16) mm2/s. The tumor volume before and at the end of external irradiation were (37.48 ± 26.83) cm3 and (4.41 ± 3.72) cm3 respectively, with tumor regression rate of before and after external irradiation of (0.86 ± 0.11). ADC values of before irradiation, 20 GY and at the end of irradiation did not correlate with tumor regression rate. D-value of ADC values between before and 20 GY external irradiation positively correlated with tumor regression rate (r = 0.423, P = 0.035). ADC value of cervical cancer increased after radiotherapy and early changes of ADC value was positively correlated with tumor regression rate, thus, ADC value could be used as a potential prediction factor for cervical cancer radiosensitivity. PMID:26550334

  8. 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. PMID:10886073

  9. Effect of depressive symptoms and social support on weight and CD4 count increase at HIV clinic in Ethiopia.

    PubMed

    Alemu, Hibret; Haile Mariam, Damen; Tsui, Amy; Ahmed, Saifudin; Shewamare, Aster

    2012-01-01

    Studies have reported an inverse relationship between depressive symptoms and weight and CD4 gain and a positive association between social support and weight and CD4 gain. The main objective of this study was to explore the effect of depressive symptoms and perceived social support on weight change and CD4 cell progression in an HIV clinic in Ethiopia. The study design was descriptive cross-sectional, with a sample of 1815 HIV-infected adults age 18 years or above. Depressive symptoms and perceived social support were the independent variables, while weight and CD4 cell count were the dependent variables. Regression modeling was the main statistical approach used for the analysis. A significant proportion of females reported depressive symptoms: being bothered by things that do not bother other people, they had been depressed, and their sleep had been restless for 5-7 days a week. A lesser proportion of males reported these problems. A significant proportion of study participants did not have someone to borrow a small amount of money (6 USD) from for immediate help and did not have somebody to support them if they were confined to bed for several weeks. Worse depressive symptoms had a negative effect on weight gain and CD4 cell progression, while better perceived social support had a positive effect on both weight gain and CD4 cell progression. Interventions that address both of these background factors need to be designed and implemented as part of the HAART program to improve weight gain and CD4 cell progression. PMID:22273149

  10. Coronal Diffusion-weighted Magnetic Resonance Imaging of the Kidney: Agreement with Axial Diffusion-weighted Magnetic Imaging in Terms of Apparent Diffusion Coefficient Values

    PubMed Central

    Wang, Hai-Yi; Wang, Jia; Tang, Ye-Huan; Ye, Hui-Yi; Ma, Lin

    2015-01-01

    Background: Coronal diffusion-weighted magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient (ADC) values have gradually become applied (following conventional axial DW-MRI) in the renal analysis. To explore whether data obtained using coronal DW-MRI are comparable with those derived using axial DW-MRI, this preliminary study sought to assess the agreement in renal ADC values between coronal DW-MRI and axial DW-MRI. Methods: Thirty-four healthy volunteers were enrolled in the study; written consents were obtained. All subjects underwent respiratory-triggered axial and coronal DW-MRI using a 1.5-MR system with b values of 0 and 800 s/mm2. The signal-to-noise ratios (SNRs) of the two DW-MRI sequences were measured and statistically compared using the paired t-test. The extent of agreement of ADC values of the upper pole, mid-pole, and lower pole of the kidney; the mean ADC values of the left kidney and right kidney; and the mean ADC values of the bilateral kidneys were evaluated via calculation of intraclass correlation coefficients (ICCs) or Bland–Altman method between the two DW-MRI sequences. Results: The SNR of coronal DW-MR images was statistically inferior to that of axial DW-MR images (P < 0.001). The ICCs of the ADC values of each region of interest, and the mean ADC values of bilateral kidneys, between the two sequences, were greater than 0.5, and the mean ADCs of the bilateral kidneys demonstrated the highest ICC (0.869; 95% confidence interval: 0.739–0.935). In addition, 94.1% (32/34), 94.1% (32/34), and 97.1% (31/34) of the ADC bias was inside the limits of agreement in terms of the mean ADC values of the left kidneys, right kidneys, and bilateral kidneys when coronal and axial DWI-MRI were compared. Conclusions: ADC values derived using coronal DW-MRI exhibited moderate-to-good agreement to those of axial DW-MRI, rendering the former an additional useful DW-MRI method, and causing the ADC values derived using the two types of DW

  11. Updates in advanced diffusion-weighted magnetic resonance imaging techniques in the evaluation of prostate cancer

    PubMed Central

    Vargas, Hebert Alberto; Lawrence, Edward Malnor; Mazaheri, Yousef; Sala, Evis

    2015-01-01

    Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer. It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DW-MRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the non-mono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging (DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer. PMID:26339460

  12. Diffusion-weighted magnetic resonance imaging of the normal canine brain.

    PubMed

    Hartmann, Antje; Söffler, Charlotte; Failing, Klaus; Schaubmar, Andreas; Kramer, Martin; Schmidt, Martin J

    2014-01-01

    Diffusion-weighted imaging (DWI) MRI has been primarily reported as a method for diagnosing cerebrovascular disease in veterinary patients. In humans, clinical applications for diffusion-weighted MRI have also included epilepsy, Alzheimer's, and Creutzfeld-Jakob disease. Before these applications can be developed in veterinary patients, more data on brain diffusion characteristics are needed. Therefore, the aim of this study was to evaluate the distribution of diffusion in the normal canine brain. Magnetic resonance imaging of the brain was performed in ten, clinically normal, purpose-bred beagle dogs. On apparent diffusion coefficient maps, regions of interest were drawn around the caudate nucleus, thalamus, piriform lobe, hippocampus, semioval center, and cerebral cortex. Statistically significant differences in mean apparent diffusion coefficient were found for the internal capsule, hippocampus, and thalamus. The highest apparent diffusion coefficient (1044.29 ± 165.21 μm(2)/s (mean ± SD (standard deviation)) was detected in the hippocampus. The lowest apparent diffusion coefficient was measured in the semioval center (721.39 ± 126.28 μm(2)/s (mean ± SD)). Significant differences in mean apparent diffusion coefficients of the caudate nucleus, thalamus, and piriform lobe were found by comparing right and left sides. Differences between brain regions may occur due to differences in myelination, neural density, or fiber orientation. The reason for the differences between right and left sides remains unclear. Data from the current study provide background for further studies of diffusion changes in dogs with brain disease. PMID:24798796

  13. 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. PMID:26512584

  14. 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.

  15. Diagnostic utility of diffusion-weighted magnetic resonance imaging in two common renal tumors

    PubMed Central

    WEN, ZHAOXIA; SUN, ZHENCHAO; WANG, YUXING

    2015-01-01

    The aim of the present study was to evaluate the utility of diffusion-weighted magnetic resonance imaging (DWI) in the diagnosis of common renal tumors. Conventional magnetic resonance imaging and DWI were performed on 85 patients with renal lesions (54 renal carcinoma and 31 renal angiomyolipoma cases). The apparent diffusion coefficient (ADC) values in each case at b=800 sec/mm2 were measured in the ADC maps using a statistical software package. The 54 cases of renal cell carcinoma showed a high signal intensity in the parenchyma, and the 31 renal angiomyolipoma cases showed a well-defined mixed signal intensity on DWI. The soft-tissue component showed a high signal intensity and the fat tissue showed a low signal intensity on DWI. When the b-value was set to 800 sec/mm2, the mean ADC was significantly lower in the renal carcinoma cases than in the renal angiomyolipoma cases. In conclusion, the measurement of ADC on DWI can reveal the structure of renal tumors, which is beneficial in diagnosing and determining the prognosis of benign and malignant renal tumors. PMID:26622890

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

    PubMed Central

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

    2015-01-01

    Introduction: 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. Methods: 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. Results: 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). Conclusions: 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. PMID:26225170

  17. Cyst infection in unilateral renal cystic disease and the role of diffusion-weighted magnetic resonance imaging.

    PubMed

    Takase, Yasukazu; Kodama, Koichi; Motoi, Isamu; Saito, Katsuhiko

    2012-11-01

    In multicystic renal diseases, cyst infection is a complex issue because of the absence of validated diagnostic methods. Unilateral renal cystic disease is a rare multicystic disease, believed to have an acquired maldevelopmental origin. Unilateral renal cystic disease is often confused with autosomal dominant polycystic kidney disease but has some distinguishing characteristics: unilateral localization, negative family history, and no progression to chronic renal failure. We describe a case of unilateral renal cystic disease with cyst infection that could be detected by diffusion-weighted magnetic resonance imaging, but not by conventional imaging techniques. Diffusion-weighted magnetic resonance imaging can be useful for detecting infected cysts, especially in multicystic renal diseases. PMID:22990058

  18. 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. PMID:25770079

  19. 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. PMID:27581179

  20. 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. PMID:23442285

  1. A finite difference method with periodic boundary conditions for simulations of diffusion-weighted magnetic resonance experiments in tissue

    NASA Astrophysics Data System (ADS)

    Russell, Greg; Harkins, Kevin D.; Secomb, Timothy W.; Galons, Jean-Philippe; Trouard, Theodore P.

    2012-02-01

    A new finite difference (FD) method for calculating the time evolution of complex transverse magnetization in diffusion-weighted magnetic resonance imaging and spectroscopy experiments is described that incorporates periodic boundary conditions. The new FD method relaxes restrictions on the allowable time step size employed in modeling which can significantly reduce computation time for simulations of large physical extent and allow for more complex, physiologically relevant, geometries to be simulated.

  2. Blade loss dynamics of a magnetically supported rotor

    NASA Astrophysics Data System (ADS)

    Viggiano, F.; Schweitzer, G.

    The equations for a rigid rotor in magnetic bearings are derived and examined for their response following a sudden unbalance created by a blade loss. The investigations concentrate on the maximum transient and steady-state response after unbalance. The analytical results are compared with experiments which were performed on a magnetic bearing test stand at our laboratory. A major result is that magnetic bearings are very well suited to cope with the loss of a rotor blade.

  3. 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. PMID:26948091

  4. 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. PMID:26462674

  5. Men’s Perceptions of Pregnancy-Related Weight Gain: A Psychosocial Firestorm (Upheaval) Intertwined With Supportive Intentions

    PubMed Central

    Montgomery, Kristen S.; Best, Melissa; Schaller, Stephanie; Kirton, Kim; Cancilla, Amanda Gordon; Carver, Priscilla; Stokes, Shannon; Horton-Hargrove, Telesha; Murry, Tina J.; Ray, Jill

    2012-01-01

    In-depth interviews were conducted with 16 men who had a significant other who had given birth within the last 5 years. Men were asked about their perceptions of pregnancy-related weight gain, and content analysis was used to identify themes from the interviews. Men described nine themes related to perinatal weight gain: (a) negative perceptions, (b) eating behaviors, (c) exercise habits, (d) health impact, (e) body changes, (f) weight-loss success, (g) “it bothered her more than me,” (h) “the weight gain wasn’t a problem,” and (i) intimacy. Together, these themes offer a glimpse into men’s experiences and highlight the discord and balance between experiencing negative feelings/perceptions and being a supportive partner. This information on how men perceive pregnancy-related weight gain can be used to develop interventions to assist men to support their significant others in meeting weight loss goals following pregnancy. PMID:23997550

  6. 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…

  7. 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.

  8. Magnetic resonance diffusion-weighted imaging: sensitivity and apparent diffusion constant in stroke.

    PubMed

    Jones, S C; Perez-Trepichio, A D; Xue, M; Furlan, A J; Awad, I A

    1994-01-01

    Magnetic resonance diffusion-weighted imaging (MR-DWI) is sensitive to the diffusibility of water and may offer characterization and anatomical localization of stroke leading to early tailored therapeutic intervention. We compared DWI, the apparent diffusion constant (ADC), and autoradiographic cerebral blood flow (CBF) in a model of focal cerebral ischemia in the rat. Sprague-Dawley rats were embolized with a single silicone cylinder injected into the internal carotid artery. Both common carotids were permanently ligated. The animals were anesthetized (isoflurane in O2), and paralyzed (gallamine). MR-DWI were obtained with a GE 4.7 T magnet (TE = 3 s, TR = 80 msec, b = 2393.10(-3) mm2/s, slice thickness 3 mm). DWI and CBF autoradiograms were compared visually. ADC was assessed in various regions, including ischemic cortex and a region homologous to ischemic cortex. Imaging times from stroke onset were 50 +/- 6 min (mean +/- SEM) for DWI, 185 +/- 17 min for a second DWI. CBF was determined at 258 +/- 15 min. The specificity was 100% at both 50 min and 185 min, indicating that there were no false positives; in 3 animals ischemia was not present. However, the sensitivity analysis indicated that early DWI yields some false negatives; at 50 min the sensitivity was 60%. We attribute our result of low early sensitivity to small infarcts in relation to the slice thickness. Later, at 185 min, sensitivity was 100%. The first ADCs were higher than the second ADC values in ischemic cortex. For infarcts larger than the slice thickness, early MR-DWI is highly sensitive for imaging evolving ischemia.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7976548

  9. The effect of arm weight support on upper limb muscle synergies during reaching movements

    PubMed Central

    2014-01-01

    Background Compensating for the effect of gravity by providing arm-weight support (WS) is a technique often utilized in the rehabilitation of patients with neurological conditions such as stroke to facilitate the performance of arm movements during therapy. Although it has been shown that, in healthy subjects as well as in stroke survivors, the use of arm WS during the performance of reaching movements leads to a general reduction, as expected, in the level of activation of upper limb muscles, the effects of different levels of WS on the characteristics of the kinematics of motion and of the activity of upper limb muscles have not been thoroughly investigated before. Methods In this study, we systematically assessed the characteristics of the kinematics of motion and of the activity of 14 upper limb muscles in a group of 9 healthy subjects who performed 3-D arm reaching movements while provided with different levels of arm WS. We studied the hand trajectory and the trunk, shoulder, and elbow joint angular displacement trajectories for different levels of arm WS. Besides, we analyzed the amplitude of the surface electromyographic (EMG) data collected from upper limb muscles and investigated patterns of coordination via the analysis of muscle synergies. Results The characteristics of the kinematics of motion varied across WS conditions but did not show distinct trends with the level of arm WS. The level of activation of upper limb muscles generally decreased, as expected, with the increase in arm WS. The same eight muscle synergies were identified in all WS conditions. Their level of activation depended on the provided level of arm WS. Conclusions The analysis of muscle synergies allowed us to identify a modular organization underlying the generation of arm reaching movements that appears to be invariant to the level of arm WS. The results of this study provide a normative dataset for the assessment of the effects of the level of arm WS on muscle synergies in stroke

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. Role of Magnetic Resonance Spectroscopy and Susceptibility Weighted Imaging in Cerebral Alveolar Echinococcosis

    PubMed Central

    YANG, Guocai; ZHANG, Qingxin; TANG, Guibo; XU, Hui; YANG, Zhen; GUO, Jianzhong; LIANG, Lin; QI, Yonghong

    2015-01-01

    Background: To analyze the characteristic performance of magnetic resonance spectroscopy (MRS) and susceptibility weighted imaging (SWI) in cerebral alveolar echinococcosis (CAE). Methods: We retrospectively analyzed 10 clinical-identified CAE cases MR performance, and summarized the MRS and SWI performance of CAE. Results: The 10 cases of CAE all had the history of primary HAE, among who 6 cases had single lesion (60%), while the rest 4 cases had multiple lesions (40%); and 4 cases were concomitant with lung metastases. MRI performance: T2WI lesions were coal-like low-signal shadow, with multiple small vesicles inside the lesions; MRS performance: NAA, Cho and Cr significantly reduced, an abnormally high and steep crest was found at 1.4 ppm; the phase diagram and strength diagram of SWI showed isointensity. Conclusion: The MRS and SWI of CAE could provide important supplemental information for the diagnosis of CAE, especially the abnormally high and steep crest at 1.4 ppm provide the reliable image basis for the diagnosis and differential diagnosis of CAE. PMID:25904955

  15. Advanced Diffusion-Weighted Magnetic Resonance Imaging Techniques of the Human Spinal Cord

    PubMed Central

    Andre, Jalal B.; Bammer, Roland

    2012-01-01

    Unlike those of the brain, advances in diffusion-weighted imaging (DWI) of the human spinal cord have been challenged by the more complicated and inhomogeneous anatomy of the spine, the differences in magnetic susceptibility between adjacent air and fluid-filled structures and the surrounding soft tissues, and the inherent limitations of the initially used echo-planar imaging techniques used to image the spine. Interval advances in DWI techniques for imaging the human spinal cord, with the specific aims of improving the diagnostic quality of the images, and the simultaneous reduction in unwanted artifacts have resulted in higher-quality images that are now able to more accurately portray the complicated underlying anatomy and depict pathologic abnormality with improved sensitivity and specificity. Diffusion tensor imaging (DTI) has benefited from the advances in DWI techniques, as DWI images form the foundation for all tractography and DTI. This review provides a synopsis of the many recent advances in DWI of the human spinal cord, as well as some of the more common clinical uses for these techniques, including DTI and tractography. PMID:22158130

  16. Diffusion weighted magnetic resonance imaging for acute stroke: practical and popular

    PubMed Central

    Tan, P L; King, D; Durkin, C J; Meagher, T M; Briley, D

    2006-01-01

    Aim To evaluate the feasibility and impact of diffusion weighted magnetic resonance imaging (DW MRI) as the first line neuroimaging of stroke at a district general hospital. Methods Prospective audit of all in‐patients admitted with clinically suspected acute stroke and referred for imaging over a consecutive 17 week period. The data collected included scan type, time from cerebral event to imaging request, and time from formal radiological request to neuroimaging. Clinicians' (general physicians, neurologists, and radiologists) perceptions were assessed by a questionnaire. Results 148 patients had neuroimaging for clinically suspected stroke during this period. Eighty one per cent of patients (120 of 148) had DW MRI as first line. Ninety two per cent of these patients had DW MRI within 24 hours of the formal radiological request. Twenty eight patients did not undergo DW MRI because lack of MRI safety, clinical state, unavailability because of maintenance service or lack of trained staff. Clinicians found the introduction of the DW MRI based service a significant improvement on computed tomography, especially for equivocal cases. Conclusion DW based MRI service is both feasible and sustainable in the setting of a district general hospital and most clinicians feel that this is a significant improvement to stroke services. PMID:16597819

  17. Meta-analysis of diffusion-weighted magnetic resonance imaging in identification of colorectal cancer

    PubMed Central

    Jia, Hongyuan; Ma, Xuelei; Zhao, Yang; Zhao, Jingyi; Liu, Rongjun; Chen, Zihang; Chen, Jinna; Huang, Jingwen; Li, Yanyan; Zhang, Jing; Wang, Feng

    2015-01-01

    Purpose: This meta-analysis aimed to evaluate the performance of diffusion-weighted magnetic resonance imaging (DWI) in identification of colorectal cancer. Methods: A systematic literature search was performed for studies that evaluated the diagnostic accuracy of DWI in identification of colorectal cancer. Methodological quality was assessed by Quality Assessment for Studies of Diagnostic Accuracy 2 (QUADAS 2) tool. After extracting data, we estimated the pooled sensitivity, specificity, likelihood ratios, and constructed summary receiver operating characteristics (SROC) curve. Results: Ten studies involving 367 malignant lesions and 178 benign lesions were considered eligible after full-text review. The pooled sensitivity and specificity were 0.95 (95% CI: 0.90-0.97) and 0.93 (95% CI: 0.85-0.97), respectively. Positive likelihood ratio and negative likelihood ratio were 12.8 (95% CI: 5.99-27.4) and 0.06 (95% CI: 0.03-0.11), respectively. The area under SROC curve was 0.98. Conclusions: Our meta-analysis indicates that DWI is a highly accurate diagnostic method in identification of colorectal cancer. PMID:26770325

  18. 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

  19. 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. PMID:22163572

  20. 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.

  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. Secondary neurolymphomatosis detected by whole-body diffusion-weighted magnetic resonance imaging: a case report.

    PubMed

    Tanaka, Hiroaki; Yoshino, Kazuhiro; Sakaida, Emiko; Hashimoto, Shinichiro; Takeda, Yusuke; Kawajiri, Chika; Takagi, Toshiyuki; Nakaseko, Chiaki

    2013-01-01

    Neurolymphomatosis (NL) is a rare clinical entity defined as peripheral nervous system infiltration by lymphoma. The diagnosis is difficult and often elusive. Whole-body diffusion-weighted magnetic resonance imaging (DW MRI) was developed to enhance the detection of vaguely delineated tumors. Here, we describe the case of a 71-year-old male with secondary NL of diffuse large B-cell lymphoma (DLBCL) that was successfully detected by whole-body DW MRI. The patient was diagnosed with DLBCL extending from the ethmoidal sinus to the nasal cavity, orbital cavity, and anterior cranial fossa. Although he was administered R-THP-COP chemotherapy and the tumor remarkably decreased in size, he developed painful paresthesia and weakness in the left upper and bilateral lower extremities during treatment. Because lymphoma cells were detected in his spinal fluid, high-dose methotrexate (MTX) and weekly intrathecal MTX and cytarabine injections were administered. Test results for lymphoma cells in the spinal fluid became negative ; however, the neurological disorders progressed. Whole-body DW MRI was performed as whole-body screening and could localize NL at the left cervical and bilateral lumbar nerve roots. Both cervical spine plain MRI and enhanced computed tomography performed around the same time could not detect the cervical lesion. Our case report suggests that whole-body DW MRI is a useful diagnostic imaging procedure, especially as whole-body screening in facilities where PET/CT is not available. PMID:24369224

  3. 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…

  4. 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.

  5. 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

  6. The role of diffusion-weighted magnetic resonance imaging in the classification of hepatic hydatid cysts.

    PubMed

    Ceçe, Hasan; Gündoğan, Mehmet; Karakaş, Omer; Karakaş, Ekrem; Boyacı, Fatıma Nurefşan; Yıldız, Sema; Ozgönül, Abdullah; Karakaş, Emel Yiğit; Cullu, Neşat; Seker, Ahmet

    2013-01-01

    The aim of the study was to classify different types of hepatic hydatid cysts (HHCs) by measuring the mean apparent diffusion coefficient (ADC) using diffusion-weighted magnetic resonance imaging (DWI). This prospective study comprised 44 patients. The 44 HHCs were classified using Gharbi ultrasonographic classification (GUC) and then T2WIs and DWIs were obtained. The ADC values were measured of the hydatid cyst (HC) subtypes. The distribution of the ADC values in the cyst groups was compared using the Kruskal-Wallis test for multi groups and the Mann-Whitney U test for paired groups. To evaluate the efficacy of ADC values in cyst diagnosis, receiver operating characteristic (ROC) analysis was performed. According to the GUC, there were 15 type 1, 11 type 2, 7 type 3, 5 type 4 and 6 type 5 HHCs. According to the ADC values in the paired comparisons, while types 1, 2 and 5 HCs were statistically differentiated from all other groups except the type 3 group, the type 4 group was differentiated from all other groups and the type 3 group was only differentiated from the type 4 group. When two groups were formed from the HHC subtypes with types 1, 2, and 3 in one group and types 4 and 5 in the other, a statistically significant difference was determined in the mean ADC values of these new groups. In conclusion the measurement of ADC values can be considered a promising parameter as an alternative to ultrasonography in the determination of subtypes of HHCs. PMID:23177089

  7. Acute pancreatitis with gradient echo T2*-weighted magnetic resonance imaging

    PubMed Central

    Tang, Meng Yue; Chen, Tian Wu; Huang, Xiao Hua; Li, Xing Hui; Wang, Si Yue; Liu, Nian

    2016-01-01

    Background To study gradient recalled echo (GRE) T2*-weighted imaging (T2*WI) for normal pancreas and acute pancreatitis (AP). Methods Fifty-one patients without any pancreatic disorders (control group) and 117 patients with AP were recruited. T2* values derived from T2*WI of the pancreas were measured for the two groups. The severity of AP was graded by the magnetic resonance severity index (MRSI) and the Acute Physiology and Chronic Healthy Evaluation II (APACHE II) scoring system. Logistic regression was used to analyze the relationship between the T2* values and AP severity. The usefulness of the T2* value for diagnosing AP and the relationship between the T2* values and the severity of AP were analyzed. Results On GRE-T2*WI, the normal pancreas showed a well-marinated and consistently homogeneous isointensity. Edematous AP, as well as the non-necrotic area in necrotizing AP, showed ill-defined but homogeneous signal intensity. AP with pancreatic hemorrhage showed a decreased T2* value and a signal loss on the signal decay curve. The T2* value of pancreas in the AP group was higher than that of the control group (t=−8.20, P<0.05). The T2* value tended to increase along with the increase in MRSI scores but not with the APACHE II scores (P>0.05). AP was associated with a one standard deviation increment in the T2* value (OR =1.37; 95% CI: 1.216–1.532). Conclusions T2*WI demonstrates a few characteristics of the normal pancreas and AP, which could potentially be helpful for detecting hemorrhage, and contributes to diagnosing AP and its severity. PMID:27190768

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

    PubMed Central

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

    2015-01-01

    Background 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). Methods 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/mm2. 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. Results 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/mm2 (r= -0.30, P=0.27). However it was significantly associated with ADC at b value of 0-1000 s/mm2 (r= -0.57, P=0.01). For this b value (0-1000 s/mm2) 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 mm2/s. Conclusion 3 Tesla DWI can possibly predict the presence of advanced fibrosis in patients with NAFLD. PMID:25608776

  9. Effects of a Body-Weight Supporting Kite on Sprint Running Kinematics in Well-Trained Sprinters.

    PubMed

    Kratky, Sascha; Buchecker, Michael; Pfusterschmied, Jürgen; Szekely, Csaba; Müller, Erich

    2016-01-01

    Data of elite sprinters indicate that faster athletes realize shorter ground contact times compared with slower individuals. Furthermore, the importance of the so-called "front side mechanics" for elite sprint performance is frequently emphasized by researchers and coaches. Recently, it was demonstrated that using a body-weight supporting kite during full-effort sprints in highly trained sprinters leads to a reduction in ground contact time. The aim of this study was to investigate possible negative effects of this body-weight supporting device on sprint running kinematics, which was not clarified in previous studies. Eleven well-trained Austrian sprinters performed flying 20-m sprints under 2 conditions: (a) free sprint (FS); and (b) body-weight supported sprint (BWS). Sprint cycle characteristics were recorded during the high-speed phase by a 16 camera 3D-system (Vicon), an optical acquisition system (Optojump-next), and a high-speed camera. Paired sample t-tests and Cohen's d effect size were used to determine differences between sprinting conditions. Compared with FS, BWS caused a decrease in ground contact time by 5.6% and an increase in air time by 5.5% (both p < 0.001), whereas stride length and rate remained unchanged. Furthermore, a reduced hip joint extension at and after take-off, an increased maximal hip joint flexion (i.e., high knee position), and a smaller horizontal distance of the touchdown to the center of gravity could be observed (all p < 0.01). These results indicate no negative effects on front side mechanics during BWS and that sprinting with a body-weight supporting kite seems to be a highly specific method to reduce ground contact time in well-trained sprinters. PMID:26270692

  10. Social support, perceptions of attractiveness, weight, and the CPI in socially anxious males and females.

    PubMed

    Haemmerlie, F M; Montgomery, R L; Melchers, J

    1988-05-01

    To see how socially anxious people function in a number of domains, Watson and Friend's (1969) Social Avoidance and Distress Scale (SAD) was administered to 101 undergraduates along with the California Personality Inventory (CPI) and the Psychosocial Support Inventory (PSI), a measure of social support. Additionally, a perceived attractiveness measure and various measures related to being overweight were taken. SAD scores correlated significantly in a negative direction with 13 of the 18 CPI scales, and those with high SAD scores had poorer social support networks. High SAD scores also were related to the perception of being overweight, but not to perceived physical attractiveness or to actually being overweight. Gender differences showed that females had more intimate social interactions and that socially anxious females relied more on their family for social support than did other people. Overall, the results suggested that the socially anxious person may have deficits in a variety of personal and interpersonal domains. PMID:3384973

  11. Development of a miniaturized, light-weight magnetic sector for a field-portable mass spectrograph

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.; Tomassian, A. D.

    1991-01-01

    A miniaturized, lightweight magnetic sector for a focal plane mass spectrograph (Mattauch-Herzog design) has been designed and fabricated by using a new high-energy-product magnet material (Nd-B-Fe alloy) and a high permeability magnet yoke material (V-Co-Fe alloy). The magnetic sector weighs less than 10 kg, has a focal plane of 5.1 cm in length, and covers a nominal mass range of 40-240 amu. Such a magnetic sector, in conjunction with an array detector and a short microbore capillary column, is well suited for the development of a field-portable gas chromatograph-mass spectrometer instrument of high performance.

  12. 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.

  13. 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

  14. 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.

  15. 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. PMID:22744303

  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. Human milk feeding supports adequate growth in infants ≤ 1250 grams birth weight

    PubMed Central

    2013-01-01

    Background Despite current nutritional strategies, premature infants remain at high risk for extrauterine growth restriction. The use of an exclusive human milk-based diet is associated with decreased incidence of necrotizing enterocolitis (NEC), but concerns exist about infants achieving adequate growth. The objective of this study was to evaluate growth velocities and incidence of extrauterine growth restriction in infants ≤ 1250 grams (g) birth weight (BW) receiving an exclusive human milk-based diet with early and rapid advancement of fortification using a donor human milk derived fortifier. Methods In a single center, prospective observational cohort study, preterm infants weighing ≤ 1250 g BW were fed an exclusive human milk-based diet until 34 weeks postmenstrual age. Human milk fortification with donor human milk derived fortifier was started at 60 mL/kg/d and advanced to provide 6 to 8 additional kilocalories per ounce (or 0.21 to 0.28 kilocalories per gram). Data for growth were compared to historical growth standards and previous human milk-fed cohorts. Results We consecutively evaluated 104 infants with mean gestational age of 27.6 ± 2.0 weeks and BW of 913 ± 181 g (mean ± standard deviation). Weight gain was 24.8 ± 5.4 g/kg/day with length 0.99 ± 0.23 cm/week and head circumference 0.72 ± 0.14 cm/week. There were 3 medical NEC cases and 1 surgical NEC case. 22 infants (21%) were small for gestational age at birth. Overall, 45 infants (43%) had extrauterine growth restriction. Weight velocity was affected by day of fortification (p = 0.005) and day of full feeds (p = 0.02). Our cohort had significantly greater growth in weight and length compared to previous entirely human milk-fed cohorts. Conclusions A feeding protocol for infants ≤ 1250 g BW providing an exclusive human milk-based diet with early and rapid advancement of fortification leads to growth meeting targeted standards with a low rate of extrauterine growth restriction. Consistent

  18. Evaluation of Public Health Professionals’ Capacity to Implement Environmental Changes Supportive of Healthy Weight

    PubMed Central

    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 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. PMID:22326561

  19. 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

  20. 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

  1. Hemorrhage detection during focused-ultrasound induced blood-brain-barrier opening by using susceptibility-weighted magnetic resonance imaging.

    PubMed

    Liu, Hao-Li; Wai, Yau-Yau; Chen, Wen-Shiang; Chen, Jin-Chung; Hsu, Po-Hong; Wu, Xin-Yu; Huang, Wen-Cheng; Yen, Tzu-Chen; Wang, Jiun-Jie

    2008-04-01

    High-intensity focused ultrasound has been discovered to be able to locally and reversibly increase the permeability of the blood-brain barrier (BBB), which can be detected using magnetic resonance imaging (MRI). However, side effects such as microhemorrhage, erythrocyte extravasations or even extensive hemorrhage may also occur. Although current contrast-enhanced T1-weighted MRI can be used to detect the changes in BBB permeability, its efficacy in detecting tissue hemorrhage after focused-ultrasound sonication remains limited. The purpose of this study is to investigate the feasibility of magnetic resonance susceptibility-weighted imaging (MR-SWI) for identifying possible tissue hemorrhage associated with disruption of the BBB induced by focused ultrasound in a rat model. The brains of 42 Sprague-Dawley rats were subjected to 107 sonications, either unilaterally or bilaterally. Localized BBB opening was achieved by delivering burst-mode focused ultrasound energy into brain tissue in the presence of microbubbles. Rats were studied by T2-weighted and contrast-enhanced T1-weighted MRI techniques, as well as by SWI. Tissue changes were analyzed histologically and the extent of apoptosis was investigated with the terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling method. The results demonstrated that SWI is more sensitive than standard T2-weighted and contrast-enhanced T1-weighted MRI techniques in detecting hemorrhages after brain sonication. Longitudinal study showed that SWI is sensitive to the recovery process of the damage and, therefore, could provide important and complementary information to the conventional MR images. Potential applications such as drug delivery in the brain might be benefited. PMID:18313204

  2. 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.

  3. 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

  4. The effectiveness of including support people in a cognitive behavioural weight loss maintenance programme for obese adults: study rationale and design.

    PubMed

    Rieger, E; Treasure, J; Swinbourne, J; Adam, B; Manns, C; Caterson, I

    2014-04-01

    The well-documented finding that obese adults have a high likelihood of weight regain following participation in behavioural weight loss programmes highlights the importance of developing more effective approaches for weight loss maintenance. One promising approach is to improve the quality of social support for effective weight control available to an obese individual by including support people in behavioural weight loss programmes. This paper describes the rationale and design of a randomized controlled trial that evaluates the effectiveness of training support people to assist obese adults in their weight management. The study entails a two-arm randomized controlled trial in which obese participants take part in a 1-year (26-session) cognitive behaviour therapy group weight management programme, including motivational interviewing strategies (CBT-MI). In one arm, participants receive CBT-MI alone, while in the second arm (CBT-MI-SP), participants also have a support person who attends 10 group sessions designed to teach effective skills for supporting an individual in healthy weight control. More specifically, support people will be trained in skills that aim to promote self-motivation for weight management. Assessments of anthropometric, medical, behavioural, motivational, psychological and social functioning take place at pre-treatment, post-treatment and a 1-year follow-up. By helping obese participants to increase and sustain their motivation and skills for weight control both during treatment and in the crucial period after treatment cessation through the ongoing input of support people, the CBT-MI-SP approach of the current study has the potential to effectively help patients to achieve sustained weight loss while minimizing the patient's need for ongoing, intensive weight control treatment with its attendant costs. PMID:25826731

  5. 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 .

  6. 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

  7. 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. PMID:25554294

  8. Influence of magnetic non-uniformity existing in a rigid rotor supported by a superconducting magnetic bearing on its whirling

    NASA Astrophysics Data System (ADS)

    Kamada, Soichiro; Amano, Ryosuke; Sugiura, Toshihiko

    2014-05-01

    Superconducting magnetic bearings (SMBs) have a significant feature over conventional bearings in terms of supporting a shaft without physical contact while attaining its stability without control. In their large-scale rotary applications, magnetization distribution of a rotor in the circumferential direction can be non-uniform and it would be better to know influence of such circumferential magnetic non-uniformity existing in a rotor on its dynamics, especially on its behaviors in the vicinity of the critical speed. In this study, further developing our previous research, we improved our analytical model so that we can adjust several different degrees of magnetic non-uniformity by arranging multiple magnetization vectors and investigated its influence. First, we simulated dynamical behavior of the system by numerical calculations and their results show that, with increasing the degree of magnetic non-uniformity, the whirling amplitude of the system, together with the difference of the amplitudes in the orthogonal directions in the whirling plane, get larger. Further, the rotational frequency at which the whirling amplitude takes its peak gets lower, which is caused by nonlinearity of the electromagnetic force. We carried out experiments and verified our numerical predicions.

  9. 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. PMID:22609397

  10. Magnetic properties of nickel and cobalt catalysts supported on nanoporous oxides.

    PubMed

    Gómez-Polo, C; Gil, A; Korili, S A; Pérez-Landazabal, J I; Recarte, V; Trujillano, R; Vicente, M A

    2008-06-01

    The aim of this work is to use magnetic measurements as a research tool in the study of possible metal-support interactions in nickel and cobalt nanoporous catalysts. Several physicochemical techniques, namely nitrogen adsorption, X-ray diffraction, temperature-programmed reduction and chemical analysis, were used to analyze the role of the preparation method and the nature of the support on the existence of such metal-support interactions and to relate them with the magnetic response of these nanoporous systems. The catalysts were prepared by incipient wetness impregnation and precipitation-deposition with two commercial oxides, gamma-Al2O3 and SiO2, as supports. The magnetic behavior of the catalysts is drastically affected by the existence of interactions between the metal and the support during the preparation procedure. The samples with weak metal-support interactions have characteristic magnetic behavior of antiferromagnetic metal oxide nanoparticles, while the ones having strong interactions display spin-glass like behavior. PMID:18681026

  11. The utility of diffusion-weighted magnetic resonance imaging in differentiation of endometriomas from hemorrhagic ovarian cysts.

    PubMed

    Balaban, Mehtap; Idilman, Ilkay S; Toprak, Huseyin; Unal, Ozlem; Ipek, Ali; Kocakoc, Ercan

    2015-01-01

    The aim was to determine the utility of diffusion-weighted magnetic resonance imaging (DW MRI) and apparent diffusion coefficient (ADC) measurements in differentiation of endometrioma and hemorrhagic ovarian cyst. A total of 24 female patients who underwent pelvic MRI with an initial diagnosis of ovarian cyst were included in the study. The final diagnosis was endometrioma in 12 patients and hemorrhagic ovarian cyst in 12 patients. We observed significantly lower ADC values in endometriomas compared with hemorrhagic ovarian cysts in all b values. DW MRI with quantitative ADC measurements can be used for differentiation of endometrioma from hemorrhagic ovarian cysts. PMID:25986161

  12. 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.

  13. 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.

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

    PubMed

    Gauyacq, Jean-Pierre; Lorente, Nicolás

    2015-11-18

    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. PMID:26471260

  15. 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

  16. 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.…

  17. Instabilities of bellows: Dependence on internal pressure, end supports, and interactions in accelerator magnet systems

    SciTech Connect

    Shutt, R.P.; Rehak, M.L.

    1990-01-01

    For superconducting magnets, one needs many bellows for connection of various helium cooling transfer lines in addition to beam tube bellows. There could be approximately 10,000 magnet interconnection bellows in the SSC exposed to an internal pressure. When axially compressed or internally pressurized, bellows can become unstable, leading to gross distortion or complete failure. If several bellows are contained in an assembly, failure modes might interact. If designed properly, large bellows can be a very feasible possibility for connecting the large tubular shells that support the magnet iron yokes and superconducting coils and contain supercritical helium for magnet cooling. We present here (1) a spring-supported bellows model, in order to develop necessary design features for bellows and end supports so that instabilities will not occur in the bellows pressure operating region, including some margin, (2) a model of three superconducting accelerator magnets connected by two large bellows, in order to ascertain that support requirements are satisfied and in order to study interaction effects between the two bellows. Reliability of bellows for our application will be stressed. 3 refs., 4 figs.

  18. Geometric and magnetic properties of Pt clusters supported on graphene: Relativistic density-functional calculations

    NASA Astrophysics Data System (ADS)

    Błoński, Piotr; Hafner, Jürgen

    2011-04-01

    The geometric and magnetic structures of small Ptn clusters (n = 1 - 5) supported on a graphene layer have been investigated using ab initio density functional calculations including spin-orbit coupling. Pt-Pt interactions were found to be much stronger than the Pt-C interactions promoting the binding to the support. As a consequence, the equilibrium structure of the gas-phase clusters is preserved if they are deposited on graphene. However, the clusters bind to graphene only via at most two Pt-C bonds: A Pt2 dumbbell prefers an upright position, the larger clusters are bound to graphene only via one edge of the planar cluster (Pt3 and Pt5) or via two terminal Pt atoms of a bent Pt4 rhombus. Evidently, the strong buckling of the graphene layer induced by the Pt-C bonds prevents the formation of a larger number of cluster-support bonds. As the local spin and orbital magnetic moments are quenched on the Pt atoms forming Pt-C bonds, the magnetic structure of the supported clusters is much more inhomogeneous as in the gas-phase. This leads to noncollinear magnetic structures and a strongly reduced magnetic anisotropy energy.

  19. 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...

  20. 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. PMID:27559354

  1. 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

  2. Diffusion-weighted magnetic resonance imaging findings in a case of metachromatic leukodystrophy.

    PubMed

    Singh, Paramdeep; Kaur, Rupinderjeet

    2016-01-01

    Metachromatic leukodystrophy (MLD) is caused by insufficiency of arylsulfatase A resulting in impaired myelination. Diffusion magnetic resonance (MR) imaging features of this disease have been rarely reported. We report diffusion MR imaging of MLD in a 12-month-old male who presented with regression of milestones and progressive spasticity. PMID:27606023

  3. Diffusion-weighted magnetic resonance imaging findings in a case of metachromatic leukodystrophy

    PubMed Central

    Singh, Paramdeep; Kaur, Rupinderjeet

    2016-01-01

    Metachromatic leukodystrophy (MLD) is caused by insufficiency of arylsulfatase A resulting in impaired myelination. Diffusion magnetic resonance (MR) imaging features of this disease have been rarely reported. We report diffusion MR imaging of MLD in a 12-month-old male who presented with regression of milestones and progressive spasticity.

  4. '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. PMID:23928985

  5. Effects of molecular weight and tacticity on the Tg of poly(methyl methacrylate) films supported by silica

    NASA Astrophysics Data System (ADS)

    Geng, Kun; Chen, Fei; Tsui, Ophelia

    The glass transition temperature (Tg) of poly(methyl methacrylate) (PMMA) films supported by silica is studied as a function of film thickness at different molecular weights (Mw) for different polymer tacticities. The Tg confinement effect is found to depend on the Mw and tacticity. For the films with a low Mw of 2.5 kg/mol,Tg is depressed for the atactic films, consistent with previous results. In contrast, the films with a higher syndiotactic content exhibit Tg enlargement as thickness decreases. We tentatively suggest this to be caused the influence of chain stiffness on the Tg that dominates at low Mw and varies with tacticity. For sufficiently high Mw, the effect of chain stiffness is expected to be small. At Mw = 50 kg/mol, the Tg confinement effect of the atatic and more syndiotactic films reverses from that observed of the low-Mw counterpart films. We suggest the chain stiffness effect to be negligible at this Mw, and attribute the opposite Tg confinement effect to be caused by a competition between the surface Tg and the substrate Tg in these films. The Tg found of bilayers made of the atatic and more syndiotatic PMMAs with this Mw supports our attribute. We are grateful to the support of NSF through the project DMR-1310536.

  6. 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

  7. 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. PMID:24977175

  8. 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. PMID:24378461

  9. Design, fabrication, and testing of the magnet liner supports for the Mirror Fusion Test Facility

    SciTech Connect

    Chang, Y.

    1981-10-09

    Heat is radiated from both the vacuum vessel that houses the magnet and the heated plasma that exists at the central region of the magnets. Approximately 30 kW of heat will be transmitted to the 311 m/sup 2/ of magnet surface area from these two heat sources. We can reduce this heat load substantially by installing liquid nitrogen (LN)-filled panels around the magnets to counteract the 300/sup 0/K vessel wall temperature. When flowing the LN inside the panels, the temperature drops to 85/sup 0/K. These LN panels also serve as thermal protection for the helium pipings in the MFTF magnet system. However, near the plasma where a higher heat load is generated, we must add water panels to protect the LN panels. All the LN panels, water panels, and their manifoldings are called the magnet liners. Of the total of 344 pieces, 240 are used directly on the magnets. The support system that mounts these LN liner panels on the magnets is the topic of this paper.

  10. Automatic Mapping Extraction from Multiecho T2-Star Weighted Magnetic Resonance Images for Improving Morphological Evaluations in Human Brain

    PubMed Central

    Yu, Shaode; Xie, Yaoqin

    2013-01-01

    Mapping extraction is useful in medical image analysis. Similarity coefficient mapping (SCM) replaced signal response to time course in tissue similarity mapping with signal response to TE changes in multiecho T2-star weighted magnetic resonance imaging without contrast agent. Since different tissues are with different sensitivities to reference signals, a new algorithm is proposed by adding a sensitivity index to SCM. It generates two mappings. One measures relative signal strength (SSM) and the other depicts fluctuation magnitude (FMM). Meanwhile, the new method is adaptive to generate a proper reference signal by maximizing the sum of contrast index (CI) from SSM and FMM without manual delineation. Based on four groups of images from multiecho T2-star weighted magnetic resonance imaging, the capacity of SSM and FMM in enhancing image contrast and morphological evaluation is validated. Average contrast improvement index (CII) of SSM is 1.57, 1.38, 1.34, and 1.41. Average CII of FMM is 2.42, 2.30, 2.24, and 2.35. Visual analysis of regions of interest demonstrates that SSM and FMM show better morphological structures than original images, T2-star mapping and SCM. These extracted mappings can be further applied in information fusion, signal investigation, and tissue segmentation. PMID:24379892

  11. Predictive classification of pediatric bipolar disorder using atlas-based diffusion weighted imaging and support vector machines.

    PubMed

    Mwangi, Benson; Wu, Mon-Ju; Bauer, Isabelle E; Modi, Haina; Zeni, Cristian P; Zunta-Soares, Giovana B; Hasan, Khader M; Soares, Jair C

    2015-11-30

    Previous studies have reported abnormalities of white-matter diffusivity in pediatric bipolar disorder. However, it has not been established whether these abnormalities are able to distinguish individual subjects with pediatric bipolar disorder from healthy controls with a high specificity and sensitivity. Diffusion-weighted imaging scans were acquired from 16 youths diagnosed with DSM-IV bipolar disorder and 16 demographically matched healthy controls. Regional white matter tissue microstructural measurements such as fractional anisotropy, axial diffusivity and radial diffusivity were computed using an atlas-based approach. These measurements were used to 'train' a support vector machine (SVM) algorithm to predict new or 'unseen' subjects' diagnostic labels. The SVM algorithm predicted individual subjects with specificity=87.5%, sensitivity=68.75%, accuracy=78.12%, positive predictive value=84.62%, negative predictive value=73.68%, area under receiver operating characteristic curve (AUROC)=0.7812 and chi-square p-value=0.0012. A pattern of reduced regional white matter fractional anisotropy was observed in pediatric bipolar disorder patients. These results suggest that atlas-based diffusion weighted imaging measurements can distinguish individual pediatric bipolar disorder patients from healthy controls. Notably, from a clinical perspective these findings will contribute to the pathophysiological understanding of pediatric bipolar disorder. PMID:26459075

  12. Locomotor step training with body weight support improves respiratory motor function in individuals with chronic spinal cord injury

    PubMed Central

    de Paleville, Daniela Terson; McKay, William; Aslan, Sevda; Folz, Rodney; Sayenko, Dimitry; Ovechkin, Alexander V.

    2013-01-01

    This prospective case-controlled clinical study was undertaken to investigate to what extent the manually assisted treadmill stepping Locomotor Training with body weight support (LT) can change respiratory function in individuals with chronic Spinal Cord Injury (SCI). Pulmonary function outcomes (Forced Vital Capacity /FVC/, Forced Expiratory Volume one second /FEV1/, Maximum Inspiratory Pressure /PImax/, Maximum Expiratory Pressure /PEmax/) and surface electromyographic (sEMG) measures of respiratory muscles activity during respiratory taskswere obtained from eight individuals with chronic C3-T12 SCI before and after 62±10 (Mean ± SD) sessions of the LT. FVC, FEV1, PImax, PEmax, amount of overall sEMG activity and rate of motor unit recruitment were significantly increased after LT (p<0.05) These results suggest that these improvements induced by the LT are likely the result of neuroplastic changes in spinal neural circuitry responsible for the activation of respiratory muscles preserved after injury. PMID:23999001

  13. 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.

  14. Cerebral hemodynamics in human acute ischemic stroke: a study with diffusion- and perfusion-weighted magnetic resonance imaging and SPECT.

    PubMed

    Liu, Y; Karonen, J O; Vanninen, R L; Ostergaard, L; Roivainen, R; Nuutinen, J; Perkiö, J; Könönen, M; Hämäläinen, A; Vanninen, E J; Soimakallio, S; Kuikka, J T; Aronen, H J

    2000-06-01

    Nineteen patients with acute ischemic stroke (<24 hours) underwent diffusion-weighted and perfusion-weighted (PWI) magnetic resonance imaging at the acute stage and 1 week later. Eleven patients also underwent technetium-99m ethyl cysteinate dimer single-photon emission computed tomography (SPECT) at the acute stage. Relative (ischemic vs. contralateral control) cerebral blood flow (relCBF), relative cerebral blood volume, and relative mean transit time were measured in the ischemic core, in the area of infarct growth, and in the eventually viable ischemic tissue on PWI maps. The relCBF was also measured from SPECT. There was a curvilinear relationship between the relCBF measured from PWI and SPECT (r = 0.854; P < 0.001). The tissue proceeding to infarction during the follow-up had significantly lower initial CBF and cerebral blood volume values on PWI maps (P < 0.001) than the eventually viable ischemic tissue had. The best value for discriminating the area of infarct growth from the eventually viable ischemic tissue was 48% for PWI relCBF and 87% for PWI relative cerebral blood volume. Combined diffusion and perfusion-weighted imaging enables one to detect hemodynamically different subregions inside the initial perfusion abnormality. Tissue survival may be different in these subregions and may be predicted. PMID:10894174

  15. When is it ok to tell patients they are overweight? General public's views of the role of doctors in supporting patients' dieting and weight management.

    PubMed

    Hart, Jo; Yelland, Sophie; Mallinson, Alice; Hussain, Zarah; Peters, Sarah

    2016-09-01

    The objective was to explore the general public's views on the role of health professionals in the management of weight with diet and the implementation of behaviour change. Semi-structured interviews were conducted. An inductive grounded theory approach utilised a coding framework; recurring concepts/themes explored in future interviews and thematic saturation achieved. Two themes summarised views on the role of health professionals in supporting dieting and weight management: responsibility to initiate talk and what patients expect. Individuals perceive health professionals as having a role in their weight management. Individuals have disparate views about responsibility for initiation of weight management talk. PMID:25759374

  16. 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...

  17. 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...

  18. 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…

  19. 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,…

  20. Evolution of the Design of Cold Mass Support for the ITER Magnet Feeder System

    NASA Astrophysics Data System (ADS)

    Lu, Kun; Song, Yuntao; Niu, Erwu; Zhou, Tinzhi; Wang, Zhongwei; Chen, Yonghua; Zhu, Yinfeng

    2013-02-01

    This paper presents the evolution of the design of cold mass support for the ITER magnet feeder system. The glass fibers in the cylinder and the flanges of the normal G10 support are discontinuous in the preliminary design. The heat load of this support from the analysis is only 4.86 W. However, the mechanical test of the prototype showed that it can only endure 9 kN lateral force, which is significantly less than the required 20 kN. So, the configuration of the glass fibers in the cylinders and flanges of this G10 support are modified by changing it to a continuous and knitted type to reinforce the support, and then a new improved prototype is manufactured and tested. It could endure 15 kN lateral forces this time, but still not meet the required 20 kN. Finally, the SS316LN material is chosen for the cold mass supports. The analysis results show that it is safe under 20 kN lateral forces with the heat load increased to 14.8 W. Considering the practical application, the requirements of strength is of primary importance. So, this SS316LN cold mass support is acceptable for the ITER magnet feeder system. On the other hand, the design idea of using continuous and knitted glass fibers to reinforce the strength of a G10 support is a good reference for the case with a lower heat load and not too high Lorentz force.

  1. 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

  2. Dopamine-secreting giant adrenal ganglioneuroma: clinical and diffusion-weighted magnetic resonance imaging findings.

    PubMed

    Polat, A V; Polat, A Kamali; Aslan, K; Atmaca, H; Karagoz, F

    2014-01-01

    We report a case of a dopamine-secreting giant primary adrenal ganglioneuroma (GN) in a 29-year-old male patient. Although the patient was clinically silent, the 24-hour urine levels of dopamine, normetanephrine, homovanillic acid and vanillyl mandelic acid were elevated. Abdominal ultrasonography and magnetic resonance imaging showed a large solid tumor with calcifications and a slightly lobular edge on the left adrenal gland. A tumor, 13 x 23 x 25 cm in size, was completely resected without morbidity. A 2-year follow-up with computed tomography showed that the postoperative course of the patient was uneventful. PMID:25073244

  3. A fully automated trabecular bone structural analysis tool based on T2* -weighted magnetic resonance imaging.

    PubMed

    Kraiger, Markus; Martirosian, Petros; Opriessnig, Peter; Eibofner, Frank; Rempp, Hansjoerg; Hofer, Michael; Schick, Fritz; Stollberger, Rudolf

    2012-03-01

    One major source affecting the precision of bone structure analysis in quantitative magnetic resonance imaging (qMRI) is inter- and intraoperator variability, inherent in delineating and tracing regions of interest along longitudinal studies. In this paper an automated analysis tool, featuring bone marrow segmentation, region of interest generation, and characterization of cancellous bone of articular joints is presented. In evaluation studies conducted at the knee joint the novel analysis tool significantly decreased the standard error of measurement and improved the sensitivity in detecting minor structural changes. It further eliminated the need of time-consuming user interaction, and thereby increasing reproducibility. PMID:21862288

  4. High resolution T2(*)-weighted Magnetic Resonance Imaging at 3 Tesla using PROPELLER-EPI.

    PubMed

    Krämer, Martin; Reichenbach, Jürgen R

    2014-05-01

    We report the application of PROPELLER-EPI for high resolution T2(*)-weighted imaging with sub-millimeter in-plane resolution on a clinical 3 Tesla scanner. Periodically rotated blades of a long-axis PROPELLER-EPI sequence were acquired with fast gradient echo readout and acquisition matrix of 320 × 50 per blade. Images were reconstructed by using 2D-gridding, phase and geometric distortion correction and compensation of resonance frequency drifts that occurred during extended measurements. To characterize these resonance frequency offsets, short FID calibration measurements were added to the PROPELLER-EPI sequence. Functional PROPELLER-EPI was performed with volunteers using a simple block design of right handed finger tapping. Results indicate that PROPELLER-EPI can be employed for fast, high resolution T2(*)-weighted imaging provided geometric distortions and possible resonance frequency drifts are properly corrected. Even small resonance frequency drifts below 10 Hz as well as non-corrected geometric distortions degraded image quality substantially. In the initial fMRI experiment image quality and signal-to-noise ratio was sufficient for obtaining high resolution functional activation maps. PMID:24439698

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. Gadolinium-based nanoparticles for highly efficient T1-weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Jang, Eunji; Han, Seungmin; Lee, Kwangyeol; Suh, Jin-Suck; Haam, Seungjoo; Huh, Yong-Min

    2014-06-01

    We developed Pyrene-Gadolinium (Py-Gd) nanoparticles as pH-sensitive magnetic resonance imaging (MRI) contrast agents capable of showing a high-Mr signal in cancer-specific environments, such as acidic conditions. Py-Gd nanoparticles were prepared by coating Py-Gd, which is a complex of gadolinium with pyrenyl molecules, with pyrenyl polyethyleneglycol PEG using a nano-emulsion method. These particles show better longitudinal relaxation time (T1) MR signals in acidic conditions than they do in neutral conditions. Furthermore, the particles exhibit biocompatibility and MR contrast effects in both in vitro and in vivo studies. From these results, we confirm that Py-Gd nanoparticles have the potential to be applied for accurate cancer diagnosis and therapy.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. Pitfalls and Limitations of Diffusion-Weighted Magnetic Resonance Imaging in the Diagnosis of Urinary Bladder Cancer

    PubMed Central

    Lin, Wei-Ching; Chen, Jeon-Hor

    2015-01-01

    Adequately selecting a therapeutic approach for bladder cancer depends on accurate grading and staging. Substantial inaccuracy of clinical staging with bimanual examination, cystoscopy, and transurethral resection of bladder tumor has facilitated the increasing utility of magnetic resonance imaging to evaluate bladder cancer. Diffusion-weighted imaging (DWI) is a noninvasive functional magnetic resonance imaging technique. The high tissue contrast between cancers and surrounding tissues on DWI is derived from the difference of water molecules motion. DWI is potentially a useful tool for the detection, characterization, and staging of bladder cancers; it can also monitor posttreatment response and provide information on predicting tumor biophysical behaviors. Despite advancements in DWI techniques and the use of quantitative analysis to evaluate the apparent diffusion coefficient values, there are some inherent limitations in DWI interpretation related to relatively poor spatial resolution, lack of cancer specificity, and lack of standardized image acquisition protocols and data analysis procedures that restrict the application of DWI and reproducibility of apparent diffusion coefficient values. In addition, inadequate bladder distension, artifacts, thinness of bladder wall, cancerous mimickers of normal bladder wall and benign lesions, and variations in the manifestation of bladder cancer may interfere with diagnosis and monitoring of treatment. Recognition of these pitfalls and limitations can minimize their impact on image interpretation, and carefully applying the analyzed results and combining with pathologic grading and staging to clinical practice can contribute to the selection of an adequate treatment method to improve patient care. PMID:26055180

  17. The Obesity Learning Centre (OLC) – a website supporting those working towards a healthy weight and reducing obesity levels

    PubMed Central

    Korjonen, Helena

    2011-01-01

    Objectives: Develop a website, the OLC, which supports those people who work on promoting a healthy weight and tackling obesity. Research shows that original networks where sharing of information and peer interaction take place create solutions to current public health challenges. Methods: Considerations that are relevant when building a new information service as well as the technical set up and information needs of users were taken into account prior to building the OLC and during continuous development and maintenance. Results: The OLC provides global news, resources and tools and link out to other networks, websites and organisations providing similar useful information. The OLC also uses social networking tools to highlight new and important information. Discussion: Networks contribute to a stronger community that can respond to emerging challenges in public health. The OLC improves connections of people and services from different backgrounds and organisations. Some challenges exist in the technical set up and also because of other aspects, e.g. public health information and differing information needs. Conclusion: Public health work programmes should include networking opportunities where public policy can be disseminated. The provision of necessary tools and resources can lead to better decision-making, save time and money and lead to improved public health outcomes. PMID:23569599

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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. PMID:26219748

  5. 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. PMID:25429691

  6. Phosphotungstic acid supported on magnetic nanoparticles as an efficient reusable catalyst for epoxidation of alkenes

    SciTech Connect

    Kooti, M.; Afshari, M.

    2012-11-15

    Highlights: ► Phosphotungstic acid supported on functionalized cobalt ferrite was prepared. ► Silica coated cobalt ferrite nanoparticles were used as support. ► This composite was successfully used as catalyst for epoxidation of alkenes. ► Oxidation reactions were carried out in the presence of t-BuOOH as oxidant. ► The catalyst can be readily separated from solution by magnetic field. -- Abstract: A new magnetically separable catalyst consisting of phosphotungstic acid supported on imidazole functionalized silica coated cobalt ferrite nanoparticles was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). This immobilized phosphotungstic acid was shown to be an efficient heterogeneous catalyst for the epoxidation of various alkenes using tert-butylhydroperoxide (t-BuOOH) as oxidant. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.

  7. 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

  8. High frequencies of elevated alkaline phosphatase activity and rickets exist in extremely low birth weight infants despite current nutritional support

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Osteopenia and rickets are common among extremely low birth weight infants (ELBW, <1000 g birth weight) despite current practices of vitamin and mineral supplementation. Few data are available evaluating the usual course of markers of mineral status in this population. Our objectives in this study w...

  9. Perianal Fistula With and Without Abscess: Assessment of Fistula Activity Using Diffusion-Weighted Magnetic Resonance Imaging

    PubMed Central

    Bakan, Selim; Olgun, Deniz Cebi; Kandemirli, Sedat Giray; Tutar, Onur; Samanci, Cesur; Dikici, Suleyman; Simsek, Osman; Rafiee, Babak; Adaletli, Ibrahim; Mihmanli, Ismail

    2015-01-01

    Background: 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. Objectives: This study aimed to determine the usefulness of diffusion-weighted (DW) MRI for assessing activity and visibility of perianal fistula. Patients and Methods: 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). Results: Mean ADC value (mm2/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). Conclusion: 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. PMID:26715982

  10. Monitoring and normalising a lack of appetite and weight loss. A discursive analysis of an online support group for bariatric surgery.

    PubMed

    Cranwell, Jo; Seymour-Smith, Sarah

    2012-06-01

    A significant adjustment in eating practices is required before and after bariatric surgery, yet we know relatively little about how patients manage these changes. In this paper, we explored how members of an online bariatric support group constructed their appetite and weight loss. Two hundred and eighty four online posts were collected, covering a period of just over a year, and analysed using discursive psychology. We found that a lack of appetite post-surgery was oriented to as something that was positively evaluated yet a cause for concern. Indeed, members monitored their food intake and marked out food consumption as a necessary activity in line with notions of healthy eating. Through monitoring members also normalised periods of weight stabilisation and were inducted into a group philosophy which encouraged a more holistic approach to post-surgery 'success'. Our analysis also highlights how monitoring and policing work as social support mechanisms which help to maintain weight management. Thus we argue, in line with others, that weight management, typically depicted as an individual responsibility, is bound up with the social practices of the online support group. We suggest that clinical advice about a loss of appetite and periods of weight stabilisation post-surgery perhaps need further explanation to patients. PMID:22342357

  11. Cardiac and Hepatic T2*-Weighted Magnetic Resonance Imaging in Transfusion Dependent Hemoglobinopathy in North West of Iran

    PubMed Central

    Valizadeh, N; Alinejad, V; Hejazi, S; Noroozi, M; Hashemi, A; Rahimi, B; Nateghi, Sh

    2015-01-01

    Background Iron overload is the main transfusion related side effects in patients with transfusion dependent hemoglobinopathies. Severe iron deposition in tissues leads to organ dysfunction. Many organs can be affected such as heart, liver, and endocrine organs. Cardiac failure and liver fibrosis are the consequent of Iron overload in transfusion dependent hemoglobinopathy. Magnetic Resonance Imaging (MRI) is a safe, noninvasive, and accurate method for the assessment of iron deposition in different tissues. This study assessed iron levels in liver and heart of the patients with transfusion dependent hemoglobinopathies. Materials and Methods The studied population consisted of 12 patients (7 male and 5 female) with transfusion dependent hemoglobinopathies, aged between 10-18 years old. Then, Cardiac and liver T2*- weighted magnetic resonance imaging (MRI) were obtained. Results In current study, 1patient (8.33%) had severe, 2 patients (16.66%) had moderate and 2(16.66%) had mild cardiac iron deposition. Out of 12 patients, 1 had severe iron deposition in liver (8.33%), 5(41.66%) and 4(33.33%) had moderate and mild hepatic iron deposition, respectively. Differences between Hepatic and cardiac iron levels were not significant between males and females (p>0.05). Conclusion Since cardiac and liver iron levels were higher than normal in most of the study group, checking ferritin level and liver function test and also echocardiography in shorter intervals (each 3 months) in involved group is suggested instead of checking routinely in 6 month intervals in patients with transfusion dependent hemoglobinopathies. PMID:26985353

  12. On the stabilization of gold nanoparticles over silica-based magnetic supports modified with organosilanes.

    PubMed

    Oliveira, Rafael L; Zanchet, Daniela; Kiyohara, Pedro K; Rossi, Liane M

    2011-04-11

    The immobilization of gold nanoparticles (Au NPs) on silica is made possible by the functionalization of the silica surfaces with organosilanes. Au NPs could only be stabilized and firmly attached to silica-support surfaces that were previously modified with amino groups. Au NPs could not be stabilized on bare silica surfaces and most of the NPs were then found in the solution. The metal-support interactions before and after the Au NP formation, observed by X-ray absorption fine structure spectroscopy (XAFS), indicate a stronger interaction of gold(III) ions with amino-modified silica surfaces than with the silanol groups in bare silica. An amino-modified, silica-based, magnetic support was used to prepare an active Au NP catalyst for the chemoselective oxidation of alcohols, a reaction of great interest for the fine chemical industry. PMID:21360597

  13. THERMAL EQUILIBRIA OF OPTICALLY THIN, MAGNETICALLY SUPPORTED, TWO-TEMPERATURE, BLACK HOLE ACCRETION DISKS

    SciTech Connect

    Oda, H.; Machida, M.; Nakamura, K. E.; Matsumoto, R.

    2010-03-20

    We obtained thermal equilibrium solutions for optically thin, two-temperature black hole accretion disks incorporating magnetic fields. The main objective of this study is to explain the bright/hard state observed during the bright/slow transition of galactic black hole candidates. We assume that the energy transfer from ions to electrons occurs via Coulomb collisions. Bremsstrahlung, synchrotron, and inverse Compton scattering are considered as the radiative cooling processes. In order to complete the set of basic equations, we specify the magnetic flux advection rate instead of beta = p{sub gas}/p{sub mag}. We find magnetically supported (low-beta), thermally stable solutions. In these solutions, the total amount of the heating via the dissipation of turbulent magnetic fields goes into electrons and balances the radiative cooling. The low-beta solutions extend to high mass accretion rates ({approx}>alpha{sup 2}M-dot{sub Edd}) and the electron temperature is moderately cool (T{sub e} {approx} 10{sup 8}-10{sup 9.5} K). High luminosities ({approx}>0.1L{sub Edd}) and moderately high energy cutoffs in the X-ray spectrum ({approx}50-200 keV) observed in the bright/hard state can be explained by the low-beta solutions.

  14. 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

  15. A tosyl-activated magnetic bead cellulose as solid support for sensitive protein detection.

    PubMed

    Yan, Junhong; Horák, Daniel; Lenfeld, Jiří; Hammond, Maria; Kamali-Moghaddam, Masood

    2013-09-10

    Magnetic bead cellulose (MBC) was prepared using sol-gel transition of viscose in the presence of maghemite (γ-Fe₂O₃) nanoparticles. The MBC particles were then activated with p-toluenesulfonyl chloride to yield tosyl-activated magnetic bead cellulose (MBC-Ts). The microspheres were characterized by light and electron microscopy, elemental analysis and atomic absorption spectroscopy to determine morphology, size, polydispersity and content of iron and tosyl groups. The functionality of the MBC-Ts microspheres was demonstrated using proximity ligation assay (PLA) to detect vascular endothelial growth factor in femtomolar concentration range. The MBC-Ts microspheres performed equally well as commercially available microparticles that are routinely used as solid support in solid phase PLA. PMID:23811391

  16. 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.

  17. Phantom for assessment of fat suppression in large field-of-view diffusion-weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Winfield, J. M.; Douglas, N. H. M.; deSouza, N. M.; Collins, D. J.

    2014-05-01

    We present the development and application of a phantom for assessment and optimization of fat suppression over a large field-of-view in diffusion-weighted magnetic resonance imaging at 1.5 T and 3 T. A Perspex cylinder (inner diameter 185 mm, height 300 mm) which contains a second cylinder (inner diameter 140 mm) was constructed. The inner cylinder was filled with water doped with copper sulphate and sodium chloride and the annulus was filled with corn oil, which closely matches the spectrum and longitudinal relaxation times of subcutaneous abdominal fat. Placement of the phantom on the couch at 45° to the z-axis presented an elliptical cross-section, which was of a similar size and shape to axial abdominal images. The use of a phantom for optimization of fat suppression allowed quantitative comparison between studies without the differences introduced by variability between human subjects. We have demonstrated that the phantom is suitable for selection of inversion delay times, spectral adiabatic inversion recovery delays and assessment of combinatorial methods of fat suppression. The phantom is valuable in protocol development and the assessment of new techniques, particularly in multi-centre trials.

  18. The Clinical Value of High-Intensity Signals on the Coronary Atherosclerotic Plaques: Noncontrast T1-Weighted Magnetic Resonance Imaging

    PubMed Central

    Ehara, Shoichi; Matsumoto, Kenji; Shimada, Kenei

    2016-01-01

    Over the past several decades, significant progress has been made in the pathohistological assessment of vulnerable plaques and in invasive intravascular imaging techniques. However, the assessment of plaque morphology by invasive modalities is of limited value for the detection of subclinical coronary atherosclerosis and the subsequent prediction or prevention of acute cardiovascular events. Recently, magnetic resonance (MR) imaging technology has reached a sufficient level of spatial resolution, which allowed the plaque visualization of large and static arteries such as the carotids and aorta. However, coronary wall imaging by MR is still challenging due to the small size of coronary arteries, cardiac and respiratory motion, and the low contrast-to-noise ratio between the coronary artery wall and the surrounding structures. Following the introduction of carotid plaque imaging with noncontrast T1-weighted imaging (T1WI), some investigators have reported that coronary artery high-intensity signals on T1WI are associated with vulnerable plaque morphology and an increased risk of future cardiac events. Although there are several limitations and issues that need to be resolved, this novel MR technique for coronary plaque imaging could influence treatment strategies for atherothrombotic disease and may be useful for understanding the pathophysiological mechanisms of atherothrombotic plaque formation. PMID:27455243

  19. Diffusion-Weighted Magnetic Resonance Imaging Findings of Kidneys with Obstructive Uropathy: Differentiation between Benign and Malignant Etiology

    PubMed Central

    Apaydin, Melda; Sönmezgöz, Fitnet; Çalık, Sinan; Bedel Koruyucu, Melike

    2014-01-01

    Purpose. In this study, we aimed to evaluate the capability of diffusion-weighted magnetic resonance imaging (DWI) in differentiation between benign and malignant etiology of obstructive uropathy. Materials and Methods. DWI was performed in 41 patients with hydronephrotic kidneys and 26 healthy volunteers. MR imaging was performed using a 1.5 T whole-body superconducting MR scanner. The signal intensities of the renal parenchyma on DWI and apparent diffusion coefficient (ADC) maps were noted. DWI was performed with the following diffusion gradient b values: 100, 600, and 1000 s/mm2. A large circular region of interest was placed in the corticomedullary junction of the kidneys. For statistical analysis, the independent-samples t test was used. Results. The mean renal ADC values for b100, b600, and b1000 in hydronephrosis patients with benign and malignant etiology and the healthy volunteers of the control group were analysed. ADC measurements of renal parenchyma in all hydronephrotic kidneys with benign and malignant etiology were found to be statistically low compared to those of normal kidneys (P < 0.05). Conclusions. There were significant differences in the ADC values of obstructed kidneys compared to those of normal kidneys. Obstructed kidneys with malignant etiology had lower ADC values for b1000 compared to obstructed kidneys with benign etiology, but these alterations were statistically insignificant. PMID:24764775

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. Detection of prostate cancer by integration of line-scan diffusion, T2-mapping and T2-weighted magnetic resonance imaging; a multichannel statistical classifier.

    PubMed

    Chan, Ian; Wells, William; Mulkern, Robert V; Haker, Steven; Zhang, Jianqing; Zou, Kelly H; Maier, Stephan E; Tempany, Clare M C

    2003-09-01

    A multichannel statistical classifier for detecting prostate cancer was developed and validated by combining information from three different magnetic resonance (MR) methodologies: T2-weighted, T2-mapping, and line scan diffusion imaging (LSDI). From these MR sequences, four different sets of image intensities were obtained: T2-weighted (T2W) from T2-weighted imaging, Apparent Diffusion Coefficient (ADC) from LSDI, and proton density (PD) and T2 (T2 Map) from T2-mapping imaging. Manually segmented tumor labels from a radiologist, which were validated by biopsy results, served as tumor "ground truth." Textural features were extracted from the images using co-occurrence matrix (CM) and discrete cosine transform (DCT). Anatomical location of voxels was described by a cylindrical coordinate system. A statistical jack-knife approach was used to evaluate our classifiers. Single-channel maximum likelihood (ML) classifiers were based on 1 of the 4 basic image intensities. Our multichannel classifiers: support vector machine (SVM) and Fisher linear discriminant (FLD), utilized five different sets of derived features. Each classifier generated a summary statistical map that indicated tumor likelihood in the peripheral zone (PZ) of the prostate gland. To assess classifier accuracy, the average areas under the receiver operator characteristic (ROC) curves over all subjects were compared. Our best FLD classifier achieved an average ROC area of 0.839(+/-0.064), and our best SVM classifier achieved an average ROC area of 0.761(+/-0.043). The T2W ML classifier, our best single-channel classifier, only achieved an average ROC area of 0.599(+/-0.146). Compared to the best single-channel ML classifier, our best multichannel FLD and SVM classifiers have statistically superior ROC performance (P=0.0003 and 0.0017, respectively) from pairwise two-sided t-test. By integrating the information from multiple images and capturing the textural and anatomical features in tumor areas, summary

  5. Muscle Activation and Estimated Relative Joint Force During Running with Weight Support on a Lower-Body Positive-Pressure Treadmill.

    PubMed

    Jensen, Bente R; Hovgaard-Hansen, Line; Cappelen, Katrine L

    2016-08-01

    Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle). It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force. PMID:26957520

  6. Active magnetic bearing-supported rotor with misaligned cageless backup bearings: A dropdown event simulation model

    NASA Astrophysics Data System (ADS)

    Halminen, Oskari; Kärkkäinen, Antti; Sopanen, Jussi; Mikkola, Aki

    2015-01-01

    Active magnetic bearings (AMB) offer considerable benefits compared to regular mechanical bearings. On the other hand, they require backup bearings to avoid damage resulting from a failure in the component itself, or in the power or control system. During a rotor-bearing contact event - when the magnetic field has disappeared and the rotor drops on the backup bearings - the structure of the backup bearings has an impact on the dynamic actions of the rotor. In this paper, the dynamics of an active magnetic bearing-supported rotor during contact with backup bearings is studied with a simulation model. Modeling of the backup bearings is done using a comprehensive cageless ball bearing model. The elasticity of the rotor is described using the finite element method (FEM) and the degrees of freedom (DOF) of the system are reduced using component mode synthesis. Verification of the misaligned cageless backup bearings model is done by comparing the simulation results against the measurement results. The verified model with misaligned cageless backup bearings is found to correspond to the features of a real system.

  7. 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.

  8. Impact of time-of-day on brain morphometric measures derived from T1-weighted magnetic resonance imaging.

    PubMed

    Trefler, Aaron; Sadeghi, Neda; Thomas, Adam G; Pierpaoli, Carlo; Baker, Chris I; Thomas, Cibu

    2016-06-01

    Measures of brain morphometry derived from T1-weighted (T1W) magnetic resonance imaging (MRI) are widely used to elucidate the relation between brain structure and function. However, the computation of T1W morphometric measures can be confounded by subject-related factors such as head motion and level of hydration. A recent study reported subtle yet significant changes in brain volume from morning to evening in a large group of patient populations as well as in healthy elderly individuals. In addition, there is a growing recognition that factors such as circadian rhythm can impact MRI measures of brain function and structure. Here, we provide a comprehensive assessment of the impact of time-of-day (TOD) on widely used measures of brain morphometry in a group of 19 healthy young adults. Our results show that (a) even in a small group of healthy adult volunteers, a highly significant reduction in apparent brain volume, from morning to evening, could be detected; (b) the apparent volume of all three major tissue compartments - gray matter, white matter, and cerebrospinal fluid - were influenced by TOD, and the magnitude of the TOD effect varied across the tissue compartments; (c) measures of cortical thickness, cortical surface area, and gray matter density computed with widely used neuroimaging software suites (i.e., FreeSurfer, FSL-VBM) were all affected by TOD, while other measures, such as curvature indices and sulcal depth, were not; and (d) the effect of TOD appeared to have a greater impact on morphometric measures of the frontal and temporal lobe than on other major lobes of the brain. Our results suggest that the TOD effect is a physiological phenomenon and that controlling for the effect of TOD is crucial for proper interpretation of apparent structural differences measured with T1W morphometry. PMID:26921714

  9. Differences between Young and Older Adults in the Control of Weight Shifting within the Surface of Support

    PubMed Central

    de Vries, Elisabeth A.; Caljouw, Simone R.; Coppens, Milou J. M.; Postema, Klaas; Verkerke, Gijsbertus J.; Lamoth, Claudine J. C.

    2014-01-01

    An important reason for falling in elderly is incorrect weight-shifting. In many daily life activities quick and accurate weight-shifting is needed to maintain balance and to prevent from falling. The present study aims to gain more insight in age-related differences in the control of weight-shifting. Nine healthy older adults (70.3±6.9 years) and twelve young adults (20.9±0.5 years) participated in the study. They performed a weight shifting task by moving the body's center of pressure, represented by a red dot on a screen, in different directions, towards targets of different sizes and at different distances projected on a screen. Movement time, fluency and accuracy of the movement were determined. Accuracy was quantified by the number of times the cursor hit the goal target before a target switch was realized (counts on goal) and by the time required to realize a target switch after the goal target was hit by the cursor for the first time (dwelling time). Fluency was expressed by the maximal deviation of the performed path with respect to the ideal path and the number of peaks, or inflections in the performed path. Significant main effects of target size, target distance and age on all outcome measures were found. With decreasing target size, increasing target distance and increasing age, movement time significantly increased and fluency and accuracy significantly decreased (i.e. increased number of peaks, maximal deviation, number of times on the goal target and longer dwelling time around the goal target). In addition, significant interaction effects of size*age and distance*age were found. Older adults needed more time to perform the weight-shifting task and their movements were less fluent and accurate compared to younger adults, especially with increasing task difficulty. This indicates that elderly might have difficulties with executing an adequate adaptation to a perturbation in daily life. PMID:24892646

  10. 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.

  11. Magnetic nano-Fe3O4-supported 1-benzyl-1,4-dihydronicotinamide (BNAH): synthesis and application in the catalytic reduction of α,β-epoxy ketones.

    PubMed

    Xu, Hua-Jian; Wan, Xin; Shen, Yong-Ya; Xu, Song; Feng, Yi-Si

    2012-03-01

    A novel magnetically recoverable organic hydride compound was successfully constructed by using silica-coated magnetic nanoparticles as a support. An as-prepared magnetic organic hydride compound, BNAH (1-benzyl-1,4-dihydronicotinamide), showed efficient activity in the catalytic reduction of α,β-epoxy ketones. After reaction, the magnetic nanoparticle-supported BNAH can be separated by simple magnetic separation which made the separation of the product easier. PMID:22324403

  12. 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. PMID:23703271

  13. Influence of Weight on Shared Core Symptoms in Eating Disorders: Support or Challenge for a Transdiagnostic Perspective?

    PubMed

    Schmitz, Catalina; Schnicker, Katja; Legenbauer, Tanja

    2016-09-01

    In terms of the transdiagnostic model of eating disorders, Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Binge Eating Disorder (BED) share the same distinctive psychopathology. However, empirical evidence showing similarities between these eating disorder diagnoses for core symptoms is scarce, and the role of weight status is unclear. Data from a total of 168 female participants were collected between April 2004 and April 2008, at an outpatient unit specialized in eating disorder treatment. Core symptoms of eating disorders were measured via self-report questionnaires. In particular, women with BED and BN showed similar patterns of core symptomatology compared with AN. However, when body mass index (BMI) was considered in the analyses, there were no differences between the three diagnostic groups in relation to body image. Differences in eating behavior are not solely triggered by weight differences, whereas body image disturbances are a transdiagnostic phenomenon among EDs and should also be considered in the treatment of BED. PMID:27118052

  14. Are Tornado-Like Magnetic Structures Able to Support Solar Prominence Plasma?

    NASA Astrophysics Data System (ADS)

    Ogunjo, S. T.; Luna Bennasar, M.; Moreno-Insertis, F.; Priest, E. R.

    2015-12-01

    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.

  15. Are Tornado-like Magnetic Structures Able to Support Solar Prominence Plasma?

    NASA Astrophysics Data System (ADS)

    Luna, M.; Moreno-Insertis, F.; Priest, E.

    2015-07-01

    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.

  16. Focal Salvage Guided by T{sub 2}-Weighted and Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Prostate Cancer Recurrences

    SciTech Connect

    Moman, Maaike R.; Berg, Cornelis A.T. van den; Boeken Kruger, Arto E.; Battermann, Jan J.; Moerland, Marinus A.; Heide, Uulke A. van der; Vulpen, Marco van

    2010-03-01

    Purpose: Salvage treatment of the entire prostate for local recurrent cancer after primary radiotherapy is associated with high toxicity rates. Our goal was to show that, using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the visualization of a recurrence, focal salvage treatment can be performed, with, potentially, a reduction in toxicity. Methods and Materials: We performed MRI, including a DCE sequence, in 7 patients with biopsy-proven locally recurrent prostate cancer. The specific regions of interest suspect for containing tumor were delineated using DCE and T{sub 2}-weighted MRI scans. Subsequently, focal salvage high-dose-rate brachytherapy plans were created to illustrate the principle of focal salvage. Total salvage treatment plans were also created for comparison. Results: The transfer constant (K{sup trans}) values from the DCE were 0.33-0.67 min{sup -1} for areas suspect for tumor and 0.07-0.25 min{sup -1} for normal tissue. In 4 cases, a focal salvage plan could be generated; 93-100% of the gross tumor volume was covered with the prescribed dose, with relative sparing of the bladder, rectum, and urethra. In the total salvage plans, 24-53% of the gross tumor volume was covered, and the organs at risk received high doses. In 3 cases, a focal salvage plan could not be created because of multifocal tumor, seminal vesicle extension, or capsular extension. Conclusion: Focal salvage treatment plans can be created in patients with local recurrent prostate cancer after radiotherapy. DCE-MRI supports the localization of the target area. This could lead to less toxicity in patients with local recurrent prostate cancer.

  17. Diffusion-weighted magnetic resonance imaging in cancer: Reported apparent diffusion coefficients, in-vitro and in-vivo reproducibility

    PubMed Central

    Jafar, Maysam M; Parsai, Arman; Miquel, Marc E

    2016-01-01

    There is considerable disparity in the published apparent diffusion coefficient (ADC) values across different anatomies. Institutions are increasingly assessing repeatability and reproducibility of the derived ADC to determine its variation, which could potentially be used as an indicator in determining tumour aggressiveness or assessing tumour response. In this manuscript, a review of selected articles published to date in healthy extra-cranial body diffusion-weighted magnetic resonance imaging is presented, detailing reported ADC values and discussing their variation across different studies. In total 115 studies were selected including 28 for liver parenchyma, 15 for kidney (renal parenchyma), 14 for spleen, 13 for pancreatic body, 6 for gallbladder, 13 for prostate, 13 for uterus (endometrium, myometrium, cervix) and 13 for fibroglandular breast tissue. Median ADC values in selected studies were found to be 1.28 × 10-3 mm2/s in liver, 1.94 × 10-3 mm2/s in kidney, 1.60 × 10-3 mm2/s in pancreatic body, 0.85 × 10-3 mm2/s in spleen, 2.73 × 10-3 mm2/s in gallbladder, 1.64 × 10-3 mm2/s and 1.31 × 10-3 mm2/s in prostate peripheral zone and central gland respectively (combined median value of 1.54×10-3 mm2/s), 1.44 × 10-3 mm2/s in endometrium, 1.53 × 10-3 mm2/s in myometrium, 1.71 × 10-3 mm2/s in cervix and 1.92 × 10-3 mm2/s in breast. In addition, six phantom studies and thirteen in vivo studies were summarized to compare repeatability and reproducibility of the measured ADC. All selected phantom studies demonstrated lower intra-scanner and inter-scanner variation compared to in vivo studies. Based on the findings of this manuscript, it is recommended that protocols need to be optimised for the body part studied and that system-induced variability must be established using a standardized phantom in any clinical study. Reproducibility of the measured ADC must also be assessed in a volunteer population, as variations are far more significant in vivo compared

  18. High signal intensity on T2-weighted cardiac magnetic resonance imaging correlates with the ventricular tachyarrhythmia in hypertrophic cardiomyopathy.

    PubMed

    Hen, Yasuki; Iguchi, Nobuo; Machida, Haruhiko; Takada, Kaori; Utanohara, Yuko; Sumiyoshi, Tetsuya

    2013-11-01

    Late gadolinium enhancement (LGE) with cardiac magnetic resonance (CMR) can predict ventricular arrhythmia and poor prognosis in hypertrophic cardiomyopathy (HCM) patients. Although myocardial T2-high signal has been reported to appear within LGE in those patients, its clinical significance remains unclear. We investigated the relationship between the T2-high signal and nonsustained ventricular tachycardia (NSVT) in HCM patients. Eighty-one HCM patients who underwent Holter ECG and CMR including T2-weighted and LGE imaging were retrospectively recruited. They were divided into NSVT-positive and NSVT-negative groups. We compared the clinical and CMR characteristics between both of the groups, and assessed predictors of NSVT with multivariate analysis. Myocardial T2-high signal was observed in 15/81 (18.5 %) patients. Each T2-high signal was localized within LGE. Significantly in the NSVT-positive group, the prevalence of atrial fibrillation [5/17 (29.4 %) vs. 2/64 (3.1 %), p = 0.0006] and T2-high signal [9/17 (52.9 %) vs. 6/64 (9.4 %), p < 0.0001] and the left ventricular (LV) end-systolic volume index (32.2 ± 15.9 ml/m(2) vs. 23.3 ± 14.9 ml/m(2), p = 0.034) and the number of segments with LGE (5.8 ± 3.3 vs. 2.7 ± 2.7, p < 0.0001) was increased, and the LV ejection fraction (54.8 ± 10.9 % vs. 65.1 ± 10.6 %, p = 0.0007) was decreased, compared to the NSVT-negative group. On multivariate analysis, the presence of atrial fibrillation (OR 29.49, p = 0.0025) and DM (OR 7.36, p = 0.0455) and T2-high signal (OR 14.96, p = 0.0014) and reduced LV ejection fraction (OR 0.93, p = 0.0222) were significantly associated with NSVT. The presence of myocardial T2-high signal is a significant independent predictor of NSVT in HCM patients. PMID:23097076

  19. Quantitative Perfusion- and Diffusion-Weighted Magnetic Resonance Imaging of Gastrointestinal Cancers Treated With Multikinase Inhibitors: A Pilot Study

    PubMed Central

    Keene, Kimberly S.; Sarver, David B.; Lee, S. Kyle; Beasley, T. Mark; Morgan, Desiree E.; Posey, James A.

    2014-01-01

    ABSTRACT BACKGROUND: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) are often used to detect the early response of solid tumors to an effective therapy. The early changes in intratumoral physiological parameters measured by DCE-MRI/DWI have been evaluated as surrogate biomarkers allowing a tailored treatment for the individual patient. METHODS: Patients with newly diagnosed, biopsy-proven, treatment-naïve gastrointestinal stromal tumor (GIST) or hepatocellular carcinoma (HCC) were enrolled prospectively after institutional review board (IRB)–approved informed consent (5 patients per tumor type). Patients with GIST were treated with sunitinib over 6 weeks. DCE-MRI/DWI was applied before therapy (baseline imaging) and at 2 and 6 weeks after therapy initiation. Patients with HCC were treated with radiation during the first 2 weeks and then with sorafenib for the next 6 weeks. DCE-MRI/DWI was applied in all patients with HCC before and after radiation therapy and at the end of sorafenib therapy. Tumor volume, perfusion parameters (Ktrans, the forward volume-transfer constant, and kep, the reverse reflux-rate constant) and the apparent diffusion coefficient (ADC) were measured. RESULTS: During 2 weeks of sunitinib therapy, GIST volume, Ktrans, and kep decreased 32 ± 13, 45 ± 24, and 42 ± 15%, respectively, whereas ADC increased 76 ± 24%. After 6 weeks of sunitinib therapy, GIST volume, Ktrans, and kep decreased 56 ± 7, 70 ± 7, and 50 ± 12%, respectively, whereas ADC increased 85 ± 33%. After completion of radiation therapy, HCC volume, Ktrans, and kep decreased 34 ± 14, 35 ± 12, and 4 ± 21%, respectively, but ADC increased 21 ± 9%. During the entire 10-week therapeutic period, HCC volume, Ktrans, and kep decreased 65 ± 15, 40 ± 9, and 26 ± 2%, respectively, whereas ADC increased 28 ± 10%. CONCLUSION: DCE-MRI/DWI can measure the perfusion and diffusion changes in GISTs or HCCs treated with

  20. 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

  1. Evaluation of diet quality and weight status of children from a low socioeconomic urban environment supports "at risk" classification.

    PubMed

    Langevin, Denise D; Kwiatkowski, Cynthia; McKay, M Geraldine; Maillet, Julie O'Sullivan; Touger-Decker, Riva; Smith, Jeffrey K; Perlman, Adam

    2007-11-01

    This cross-sectional study evaluated diet quality and weight status in 248 randomly selected low-income urban children, aged 7 to 13 years, who were participating in a larger study on the effectiveness of multivitamin supplementation on school performance. Food frequency questionnaires were used to determine intake of total calories and food groups, selected micronutrients, and amount and percent of calories from sweets. Results were compared to age-appropriate recommendations of the Food Guide Pyramid and to the Dietary Reference Intakes. Height, weight, and ages obtained from current-year student health records were used to calculate body mass index (calculated as kg/m(2)) percentile for age. Of 193 participants with usable food frequencies and available weight, height, sex, and age, 22% (n=43) were at risk for overweight and 36% (n=69) were overweight. More than 75% of participants failed to meet recommended servings for grains, vegetables, dairy, and fruit groups, and mean intake of each of these food groups was significantly less than recommendations (P<0.001). Twenty-five percent or more of subjects did not meet Recommended Dietary Allowances for iron and folate. Mean intake of calcium was below the Adequate Intake for calcium and 76% of children 8 years old and younger and 93% of children 9 years old and older did not meet the Adequate Intake for calcium. Mean calorie intake was 1,723 kcal (standard deviation+/-924) and mean percent of calories from carbohydrate, protein, and fat was 57%, 13%, and 32%, respectively. No correlation was found between total calories, total dietary sugar, or percent of calories from sweets and body mass index. Results of this study suggest that these urban children may be "at risk," based on the high percentage who are overweight and have insufficient food group consumption and micronutrient intake. PMID:17964318

  2. Diagnostic Utility of Diffusion-weighted Magnetic Resonance Imaging in Differentiating Small Solid Renal Tumors (≤4 cm) at 3.0T Magnetic Resonance Imaging

    PubMed Central

    Zhang, Han-Mei; Wu, Ying-Hua; Gan, Qi; Lyu, Xiao; Zhu, Xiang-Lan; Kuang, Min; Liu, Rong-Bo; Huang, Zi-Xing; Yuan, Fang; Liu, Xi-Jiao; Song, Bin

    2015-01-01

    Background: The aim of this study was to assess the performance of apparent diffusion coefficient (ADC) measurement obtained with diffusion-weighted magnetic resonance imaging (DW-MRI) to distinguish renal cell carcinomas (RCCs) from small benign solid renal tumors (≤4 cm). Methods: In this cross-sectional study, 49 consecutive patients with histopathologically confirmed small solid renal tumors, and seven healthy volunteers were imaged using nonenhanced MRI and DW-MRI. The ADC map was calculated using the b values of 0, 50, 400, and 600 s/mm2 and values compared via the Kruskal–Wallis and Mann–Whitney tests. The utility of ADC for differentiating RCCs and benign lesions was assessed using a receiver operating characteristic curve. Multiple nonenhanced MRI features were analyzed by Logistic regression. Results: The tumors consisted of 33 cases of clear-cell RCCs (ccRCCs) and 16 cases of benign tumors, including 14 cases of minimal fat angiomyolipomas and 2 cases of oncocytomas. The ADCs showed significant differences among benign tumors ([0.90 ± 0.52] × 10−3 mm2/s), ccRCCs ([1.53 ± 0.31] × 10−3 mm2/s) and the normal renal parenchyma ([2.22 ± 0.12] × 10−3 mm2/s) (P < 0.001). Moreover, there was statistically significant difference between high and low-grade ccRCCs (P = 0.004). Using a cut-off ADC of 1.36 × 10−3 mm2/s, DW-MRI resulted in an area under the curve (AUC), sensitivity, and specificity equal to 0.839, 75.8%, and 87.5%, respectively. Nonenhanced MRI alone and the combination of imaging methods led to an AUC, sensitivity and specificity equal to 0.919, 93.9%, and 81.2%, 0.998, 97%, and 100%, respectively. The Logistic regression showed that the location of the center of the tumor (inside the contour of the kidney) and appearance of stiff blood vessel were significantly helpful for diagnosing ccRCCs. Conclusions: DW-MRI has potential in distinguishing ccRCCs from benign lesions in human small solid renal tumors (≤4 cm), and in

  3. Effects of upper limb positions and weight support roles on quasi-static seated postural stability in individuals with spinal cord injury.

    PubMed

    Grangeon, Murielle; Gagnon, Dany; Gauthier, Cindy; Jacquemin, Géraldine; Masani, Kei; Popovic, Milos R

    2012-07-01

    Seated postural stability has not been studied extensively in individuals with spinal cord injury (SCI). The main purpose of this study was to compare the effects of upper limb (U/L) positions and U/L weight support roles on quasi-static postural stability between individuals with SCI and healthy controls. Fourteen individuals with SCI and 14 healthy controls sat on an instrumented seat with their feet resting on force plates and randomly maintained five short-sitting positions for 60s with or without hand support. Center-of-pressure (COP) measures based on displacement and frequency series were computed. Individuals with SCI exhibited greater mean COP displacement and velocity measures compared to healthy controls, as well as lower COP frequency measures, irrespective of the U/L positions and weight support roles, confirming reduced stability and a difference in preferential postural regulation strategies. The use of U/L support is a compensatory strategy that influences seated stability in individuals with SCI. PMID:22771157

  4. 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.

  5. 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

    2016-03-01

    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. PMID:26883386

  6. Development of a Support Vector Machine - Based Image Analysis System for Focal Liver Lesions Classification in Magnetic Resonance Images

    NASA Astrophysics Data System (ADS)

    Gatos, I.; Tsantis, S.; Karamesini, M.; Skouroliakou, A.; Kagadis, G.

    2015-09-01

    Purpose: The design and implementation of a computer-based image analysis system employing the support vector machine (SVM) classifier system for the classification of Focal Liver Lesions (FLLs) on routine non-enhanced, T2-weighted Magnetic Resonance (MR) images. Materials and Methods: The study comprised 92 patients; each one of them has undergone MRI performed on a Magnetom Concerto (Siemens). Typical signs on dynamic contrast-enhanced MRI and biopsies were employed towards a three class categorization of the 92 cases: 40-benign FLLs, 25-Hepatocellular Carcinomas (HCC) within Cirrhotic liver parenchyma and 27-liver metastases from Non-Cirrhotic liver. Prior to FLLs classification an automated lesion segmentation algorithm based on Marcov Random Fields was employed in order to acquire each FLL Region of Interest. 42 texture features derived from the gray-level histogram, co-occurrence and run-length matrices and 12 morphological features were obtained from each lesion. Stepwise multi-linear regression analysis was utilized to avoid feature redundancy leading to a feature subset that fed the multiclass SVM classifier designed for lesion classification. SVM System evaluation was performed by means of leave-one-out method and ROC analysis. Results: Maximum accuracy for all three classes (90.0%) was obtained by means of the Radial Basis Kernel Function and three textural features (Inverse- Different-Moment, Sum-Variance and Long-Run-Emphasis) that describe lesion's contrast, variability and shape complexity. Sensitivity values for the three classes were 92.5%, 81.5% and 96.2% respectively, whereas specificity values were 94.2%, 95.3% and 95.5%. The AUC value achieved for the selected subset was 0.89 with 0.81 - 0.94 confidence interval. Conclusion: The proposed SVM system exhibit promising results that could be utilized as a second opinion tool to the radiologist in order to decrease the time/cost of diagnosis and the need for patients to undergo invasive examination.

  7. Usefulness of extracorporeal membrane oxygenation using double roller pumps in a low body weight newborn: A novel strategy for mechanical circulatory support in an infant.

    PubMed

    Nakanishi, Keisuke; Kato, Tomoko; Kawasaki, Shiori; Amano, Atsushi

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) with a centrifugal pump requires a certain flow rate; therefore, its application for low body weight infants is frequently accompanied by oxygenator membrane malfunction and/or inadequate perfusion. To prevent low-flow associated complications, we report a case in which a novel system of dual roller pumps was used. A baby girl with a body mass index 0.25 m(2), who experienced difficulty weaning from cardiopulmonary bypass after a Norwood-like operation, required an ECMO. Concerns for the tube lifespan reduction due to roller pump friction led to the use of a double roller pump circulation. The termination of ECMO during tube exchange is not needed, because circulation is maintained by another roller pump. The novel strategy of ECMO with double roller pumps will allow low perfusion rate to provide adequate circulatory support for low body weight patients. PMID:27011702

  8. Usefulness of extracorporeal membrane oxygenation using double roller pumps in a low body weight newborn: A novel strategy for mechanical circulatory support in an infant

    PubMed Central

    Nakanishi, Keisuke; Kato, Tomoko; Kawasaki, Shiori; Amano, Atsushi

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) with a centrifugal pump requires a certain flow rate; therefore, its application for low body weight infants is frequently accompanied by oxygenator membrane malfunction and/or inadequate perfusion. To prevent low-flow associated complications, we report a case in which a novel system of dual roller pumps was used. A baby girl with a body mass index 0.25 m2, who experienced difficulty weaning from cardiopulmonary bypass after a Norwood-like operation, required an ECMO. Concerns for the tube lifespan reduction due to roller pump friction led to the use of a double roller pump circulation. The termination of ECMO during tube exchange is not needed, because circulation is maintained by another roller pump. The novel strategy of ECMO with double roller pumps will allow low perfusion rate to provide adequate circulatory support for low body weight patients. PMID:27011702

  9. Copper(0) nanoparticles supported on silica-coated cobalt ferrite magnetic particles: cost effective catalyst in the hydrolysis of ammonia-borane with an exceptional reusability performance.

    PubMed

    Kaya, Murat; Zahmakiran, Mehmet; Ozkar, Saim; Volkan, Mürvet

    2012-08-01

    Herein we report the development of a new and cost-effective nanocomposite catalyst for the hydrolysis of ammonia-borane (NH(3)BH(3)), which is considered to be one of the most promising solid hydrogen carriers because of its high gravimetric hydrogen storage capacity (19.6% wt) and low molecular weight. The new catalyst system consisting of copper nanoparticles supported on magnetic SiO(2)/CoFe(2)O(4) particles was reproducibly prepared by wet-impregnation of Cu(II) ions on SiO(2)/CoFe(2)O(4) followed by in situ reduction of the Cu(II) ions on the surface of magnetic support during the hydrolysis of NH(3)BH(3) and characterized by ICP-MS, XRD, XPS, TEM, HR-TEM and N(2) adsorption-desorption technique. Copper nanoparticles supported on silica coated cobalt(II) ferrite SiO(2)/CoFe(2)O(4) (CuNPs@SCF) act as highly active catalyst in the hydrolysis of ammonia-borane, providing an initial turnover frequency of TOF = 2400 h(-1) at room temperature, which is not only higher than all the non-noble metal catalysts but also higher than the majority of the noble metal based homogeneous and heterogeneous catalysts employed in the same reaction. More importantly, they were easily recovered by using a permanent magnet in the reactor wall and reused for up to 10 recycles without losing their inherent catalytic activity significantly, which demonstrates the exceptional reusability of the CuNPs@SCF catalyst. PMID:22856878

  10. Diagnostic Performance of Diffusion-weighted Magnetic Resonance Imaging in Bone Malignancy: Evidence From a Meta-Analysis.

    PubMed

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

    2015-11-01

    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/mm 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 both basis. Our

  11. IntelliHealth: A medical decision support application using a novel weighted multi-layer classifier ensemble framework.

    PubMed

    Bashir, Saba; Qamar, Usman; Khan, Farhan Hassan

    2016-02-01

    Accuracy plays a vital role in the medical field as it concerns with the life of an individual. Extensive research has been conducted on disease classification and prediction using machine learning techniques. However, there is no agreement on which classifier produces the best results. A specific classifier may be better than others for a specific dataset, but another classifier could perform better for some other dataset. Ensemble of classifiers has been proved to be an effective way to improve classification accuracy. In this research we present an ensemble framework with multi-layer classification using enhanced bagging and optimized weighting. The proposed model called "HM-BagMoov" overcomes the limitations of conventional performance bottlenecks by utilizing an ensemble of seven heterogeneous classifiers. The framework is evaluated on five different heart disease datasets, four breast cancer datasets, two diabetes datasets, two liver disease datasets and one hepatitis dataset obtained from public repositories. The analysis of the results show that ensemble framework achieved the highest accuracy, sensitivity and F-Measure when compared with individual classifiers for all the diseases. In addition to this, the ensemble framework also achieved the highest accuracy when compared with the state of the art techniques. An application named "IntelliHealth" is also developed based on proposed model that may be used by hospitals/doctors for diagnostic advice. PMID:26703093

  12. Supported Exercise Improves Controlled Eating and Weight through Its Effects on Psychosocial Factors: Extending a Systematic Research Program Toward Treatment Development

    PubMed Central

    Annesi, James J

    2012-01-01

    Background: Behavioral weight-loss treatments have been overwhelmingly unsuccessful. Many inadequately address both behavioral theory and extant research—especially in regard to the lack of viability of simply educating individuals on improved eating and exercise behaviors. Objective: The aim was to synthesize research on associations of changes in exercise behaviors, psychosocial factors, eating behaviors, and weight; and then conduct further direct testing to inform the development of an improved treatment approach. Methods: A systematic program of health behavior-change research based on social cognitive theory, and extensions of that theory applied to exercise and weight loss, was first reviewed. Then, to extend this research toward treatment development and application, a field-based study of obese adults was conducted. Treatments incorporated a consistent component of cognitive-behaviorally supported exercise during 26 weeks that was paired with either standard nutrition education (n = 183) or cognitive-behavioral methods for controlled eating that emphasized self-regulatory methods such as goal setting and caloric tracking, cognitive restructuring, and eating cue awareness (n = 247). Results: Both treatment conditions were associated with improved self-efficacy, self-regulation, mood, exercise, fruit and vegetable consumption, weight, and waist circumference; with improvements in self-regulation for eating, fruit and vegetable consumption, weight, and waist circumference significantly greater in the cognitive-behavioral nutrition condition. Changes in exercise- and eating-related self-efficacy and self-regulation were associated with changes in exercise and eating (R2 = 0.40 and 0.17, respectively), with mood change increasing the explanatory power to R2 = 0.43 and 0.20. Improved self-efficacy and self-regulation for exercise carried over to self-efficacy and self-regulation for controlled eating (β= 0.53 and 0.68, respectively). Conclusions: Development

  13. Design of set-point weighting PI{sup λ} + D{sup μ} controller for vertical magnetic flux controller in Damavand tokamak

    SciTech Connect

    Rasouli, H.; Fatehi, A.

    2014-12-15

    In this paper, a simple method is presented for tuning weighted PI{sup λ} + D{sup 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{sup λ} + D{sup 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. Design of a superconducting 28 GHz ion source magnet for FRIB using a shell-based support structure

    DOE PAGESBeta

    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 themore » 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.« less

  15. Weighting Statistical Inputs for Data Used to Support Effective Decision Making During Severe Emergency Weather and Environmental Events

    NASA Technical Reports Server (NTRS)

    Gardner, Adrian

    2010-01-01

    National Aeronautical and Space Administration (NASA) weather and atmospheric environmental organizations are insatiable consumers of geophysical, hydrometeorological and solar weather statistics. The expanding array of internet-worked sensors producing targeted physical measurements has generated an almost factorial explosion of near real-time inputs to topical statistical datasets. Normalizing and value-based parsing of such statistical datasets in support of time-constrained weather and environmental alerts and warnings is essential, even with dedicated high-performance computational capabilities. What are the optimal indicators for advanced decision making? How do we recognize the line between sufficient statistical sampling and excessive, mission destructive sampling ? How do we assure that the normalization and parsing process, when interpolated through numerical models, yields accurate and actionable alerts and warnings? This presentation will address the integrated means and methods to achieve desired outputs for NASA and consumers of its data.

  16. Molecular weight dependence of segmental alignment in a sheared polymer melt: A deuterium nuclear magnetic resonance investigation

    NASA Astrophysics Data System (ADS)

    Cormier, Ryan J.; Callaghan, Paul T.

    2002-06-01

    2H NMR quadrupole interaction spectroscopy has been used to measure the molecular weight dependence of poly(dimethylsiloxane) chain deformation under shear in a cylindrical Couette cell while NMR velocimetry has been used to directly measure shear rates. The signals were acquired from a perdeuterated benzene probe molecule, which provides a motionally averaged sampling of the entire segmental ensemble. We have measured the dependence on shear rate of the SXX (velocity), SYY (velocity gradient), and SZZ (vorticity) elements of the segmented alignment tensor, fitting the data using the standard Doi-Edwards theory and modified to allow for convected constraint release. Our results suggest that the tube disengagement times scale as molecular weight to the power 3.5±0.1, consistent with the usual 3.4 power law. Our velocimetry measurements indicate a reproducible and consistent slip occurring at high molecular weights (>1 M Dalton), a phenomenon which is independently observed in a lower than expected chain deformation.

  17. ASA conference on radiation and health: Health effects of electric and magnetic fields: Statistical support for research strategies. Final report

    SciTech Connect

    Not Available

    1990-05-01

    This report is a collection of papers documenting presentations made at the VIII ASA (American Statistical Association) Conference on Radiation and Health entitled Health Effects of Electric and Magnetic Fields: Statistical Support for Research Strategies. Individual papers are abstracted and indexed for the database.

  18. Ruthenium supported on magnetic nanoparticles: An efficient and recoverable catalyst for hydrogenation of alkynes and transfer hydrogenation of carbonyl compounds

    EPA Science Inventory

    Ruthenium supported on surface modified magnetic nanoparticles (NiFe2O4) has been successfully synthesized and applied for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The ...

  19. Biochemical support for the "threshold" theory of creativity: a magnetic resonance spectroscopy study.

    PubMed

    Jung, Rex E; Gasparovic, Charles; Chavez, Robert S; Flores, Ranee A; Smith, Shirley M; Caprihan, Arvind; Yeo, Ronald A

    2009-04-22

    A broadly accepted definition of creativity refers to the production of something both novel and useful within a given social context. Studies of patients with neurological and psychiatric disorders and neuroimaging studies of healthy controls have each drawn attention to frontal and temporal lobe contributions to creativity. Based on previous magnetic resonance (MR) spectroscopy studies demonstrating relationships between cognitive ability and concentrations of N-acetyl-aspartate (NAA), a common neurometabolite, we hypothesized that NAA assessed in gray and white matter (from a supraventricular slab) would relate to laboratory measures of creativity. MR imaging and divergent thinking measures were obtained in a cohort of 56 healthy controls. Independent judges ranked the creative products of each participant, from which a "Composite Creativity Index" (CCI) was created. Different patterns of correlations between NAA and CCI were found in higher verbal ability versus lower verbal ability participants, providing neurobiological support for a critical "threshold" regarding the relationship between intelligence and creativity. To our knowledge, this is the first report assessing the relationship between brain chemistry and creative cognition, as measured with divergent thinking, in a cohort comprised exclusively of normal, healthy participants. PMID:19386928

  20. Sting-free measurements on a magnetically supported right circular cylinder aligned with the free stream

    NASA Astrophysics Data System (ADS)

    Higuchi, Hiroshi; Sawada, Hideo; Kato, Hiroyuki

    The flow over cylinders of varying fineness ratio (length to diameter) aligned with the free stream was examined using a magnetic suspension and balance system in order to avoid model support interference. The drag coefficient variation of a right circular cylinder was obtained for a wide range of fineness ratios. Particle image velocimetry (PIV) was used to examine the flow field, particularly the behaviour of the leading-edge separation shear layer and its effect on the wake. Reynolds numbers based on the cylinder diameter ranged from 5105, while the major portion of the experiment was conducted at ReD=1.0×105. For moderately large fineness ratio, the shear layer reattaches with subsequent growth of the boundary layer, whereas over shorter cylinders, the shear layer remains detached. Differences in the wake recirculation region and the immediate wake patterns are clarified in terms of both the mean velocity and turbulent flow fields, including longitudinal vortical structures in the cross-flow plane of the wake. The minimum drag corresponded to the fineness ratio for which the separated shear layer reattached at the trailing edge of the cylinder. The base pressure was obtained with a telemetry technique. Pressure fields and aerodynamic force fluctuations are also discussed.

  1. Improve the image quality of orbital 3 T diffusion-weighted magnetic resonance imaging with readout-segmented echo-planar imaging.

    PubMed

    Xu, Xiao-Quan; Liu, Jun; Hu, Hao; Su, Guo-Yi; Zhang, Yu-Dong; Shi, Hai-Bin; Wu, Fei-Yun

    2016-01-01

    The aim of our study is to compare the image quality of readout-segmented echo-planar imaging (rs-EPI) and that of standard single-shot EPI (ss-EPI) in orbital 3 T diffusion-weighted (DW) magnetic resonance (MR) imaging in healthy subjects. Forty-two volunteers underwent two sets of orbital DW imaging scan at a 3 T MR unit, and image quality was assessed qualitatively and quantitatively. As a result, we found that rs-EPI could provide better image quality than standard ss-EPI, while no significant difference was found on the apparent diffusion coefficient between the two sets of DW images. PMID:27317226

  2. Effects of Arm Weight Support Training to Promote Recovery of Upper Limb Function for Subacute Patients after Stroke with Different Levels of Arm Impairments

    PubMed Central

    Chan, Irene H. L.; Chan, Dora Y. L.; Wang, Apple Q. L.; Cheng, Eddy K. N.; Chau, Pinky H. Y.; Chow, Kathy K. Y.; Cheung, Hobby K. Y.

    2016-01-01

    Purpose. The goal of this study was to investigate the effects of arm weight support training using the ArmeoSpring for subacute patients after stroke with different levels of hemiplegic arm impairments. Methods. 48 inpatients with subacute stroke, stratified into 3 groups from mild to severe upper extremity impairment, were engaged in ArmeoSpring training for 45 minutes daily, 5 days per week for 3 weeks, in addition to conventional rehabilitation. Evaluations were conducted at three measurement occasions: immediately before training (T1); immediately after training (T2); and at a 3-week follow-up (T3) by a blind rater. Results. Shoulder flexion active range of motion, Upper Extremity Scores in the Fugl-Meyer Assessment (FMA), and Vertical Catch had the greatest differences in gain scores for patients between severe and moderate impairments, whereas FMA Hand Scores had significant differences in gain scores between moderate and mild impairments. There was no significant change in muscle tone or hand-path ratios between T1, T2, and T3 within the groups. Conclusion. Arm weight support training is beneficial for subacute stroke patients with moderate to severe arm impairments, especially to improve vertical control such as shoulder flexion, and there were no adverse effects in muscle tone. PMID:27517053

  3. Effects of Arm Weight Support Training to Promote Recovery of Upper Limb Function for Subacute Patients after Stroke with Different Levels of Arm Impairments.

    PubMed

    Chan, Irene H L; Fong, Kenneth N K; Chan, Dora Y L; Wang, Apple Q L; Cheng, Eddy K N; Chau, Pinky H Y; Chow, Kathy K Y; Cheung, Hobby K Y

    2016-01-01

    Purpose. The goal of this study was to investigate the effects of arm weight support training using the ArmeoSpring for subacute patients after stroke with different levels of hemiplegic arm impairments. Methods. 48 inpatients with subacute stroke, stratified into 3 groups from mild to severe upper extremity impairment, were engaged in ArmeoSpring training for 45 minutes daily, 5 days per week for 3 weeks, in addition to conventional rehabilitation. Evaluations were conducted at three measurement occasions: immediately before training (T1); immediately after training (T2); and at a 3-week follow-up (T3) by a blind rater. Results. Shoulder flexion active range of motion, Upper Extremity Scores in the Fugl-Meyer Assessment (FMA), and Vertical Catch had the greatest differences in gain scores for patients between severe and moderate impairments, whereas FMA Hand Scores had significant differences in gain scores between moderate and mild impairments. There was no significant change in muscle tone or hand-path ratios between T1, T2, and T3 within the groups. Conclusion. Arm weight support training is beneficial for subacute stroke patients with moderate to severe arm impairments, especially to improve vertical control such as shoulder flexion, and there were no adverse effects in muscle tone. PMID:27517053

  4. Magnetic anisotropy of heteronuclear dimers in the gas phase and supported on graphene: relativistic density-functional calculations.

    PubMed

    Błoński, Piotr; Hafner, Jürgen

    2014-04-01

    The structural and magnetic properties of mixed PtCo, PtFe, and IrCo dimers in the gas phase and supported on a free-standing graphene layer have been calculated using density-functional theory, both in the scalar-relativistic limit and self-consistently including spin-orbit coupling. The influence of the strong magnetic moments of the 3d atoms on the spin and orbital moments of the 5d atoms, and the influence of the strong spin-orbit coupling contributed by the 5d atom on the orbital moments of the 3d atoms have been studied in detail. The magnetic anisotropy energy is found to depend very sensitively on the nature of the eigenstates in the vicinity of the Fermi level, as determined by band filling, exchange splitting and spin-orbit coupling. The large magnetic anisotropy energy of free PtCo and IrCo dimers relative to the easy direction parallel to the dimer axis is coupled to a strong anisotropy of the orbital magnetic moments of the Co atom for both dimers, and also on the Ir atom in IrCo. In contrast the PtFe dimer shows a weak perpendicular anisotropy and only small spin and orbital anisotropies of opposite sign on the two atoms. For dimers supported on graphene, the strong binding within the dimer and the stronger interaction of the 3d atom with the substrate stabilizes an upright geometry. Spin and orbital moments on the 3d atom are strongly quenched, but due to the weaker binding within the dimer the properties of the 5d atom are more free-atom-like with increased spin and orbital moments. The changes in the magnetic moment are reflected in the structure of the electronic eigenstates near the Fermi level, for all three dimers the easy magnetic direction is now parallel to the dimer axis and perpendicular to the graphene layer. The already very large magnetic anisotropy energy (MAE) of IrCo is further enhanced by the interaction with the support, the MAE of PtFe changes sign, and that of the PtCo dimer is reduced. These changes are discussed in relation to

  5. Magnetic iron oxide/clay composites: effect of the layer silicate support on the microstructure and phase formation of magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Szabó, Tamás; Bakandritsos, Aristides; Tzitzios, Vassilios; Papp, Szilvia; Korösi, László; Galbács, Gábor; Musabekov, Kuanyshbek; Bolatova, Didara; Petridis, Dimitris; Dékány, Imre

    2007-07-01

    Magnetic iron oxide nanoparticles were synthesized on two different clay supports: natural montmorillonite and synthetic laponite. The nanocomposites obtained, characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), x-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, small-angle x-ray scattering (SAXS), vibrating sample magnetometry and Mössbauer spectroscopy, were found to exhibit highly different physicochemical properties despite their similar iron content. The observed size effect of the layered silicate support, resulting in the high abundance of very small particles (diameter of 1-5 nm) on laponite, was explained in terms of the difference between the surface charge densities and the lamellar dimensions of the clay substrates. Moreover, it was revealed that the nature of the layered support greatly affected the nanostructure (fractal dimensions, surface area, porosity) of the formed hybrid solids as well as the phase formation of iron oxide crystals. The high surface area laponite composites, due to the dominance of very small iron oxide particles, exhibited more pronounced superparamagnetic behaviour as compared to the montmorillonite samples prepared under identical conditions. The observed higher saturation magnetization of the laponite composites, attributed to their lower content in the antiferromagnetic hematite and to the onset of superferromagnetism in the aggregated particles, shows their excellent utility for adsorption/magnetic separation.

  6. Potential for Differentiation of Pseudoprogression From True Tumor Progression With Dynamic Susceptibility-Weighted Contrast-Enhanced Magnetic Resonance Imaging Using Ferumoxytol vs. Gadoteridol: A Pilot Study

    SciTech Connect

    Gahramanov, Seymur; Raslan, Ahmed M.; Muldoon, Leslie L.; Hamilton, Bronwyn E.; Rooney, William D.; Varallyay, Csanad G.; Njus, Jeffrey M.; Haluska, Marianne; Neuwelt, Edward A.

    2011-02-01

    Purpose: We evaluated dynamic susceptibility-weighted contrast-enhanced magnetic resonance imaging (DSC-MRI) using gadoteridol in comparison to the iron oxide nanoparticle blood pool agent, ferumoxytol, in patients with glioblastoma multiforme (GBM) who received standard radiochemotherapy (RCT). Methods and Materials: Fourteen patients with GBM received standard RCT and underwent 19 MRI sessions that included DSC-MRI acquisitions with gadoteridol on Day 1 and ferumoxytol on Day 2. Relative cerebral blood volume (rCBV) values were calculated from DSC data obtained from each contrast agent. T1-weighted acquisition post-gadoteridol administration was used to identify enhancing regions. Results: In seven MRI sessions of clinically presumptive active tumor, gadoteridol-DSC showed low rCBV in three and high rCBV in four, whereas ferumoxytol-DSC showed high rCBV in all seven sessions (p = 0.002). After RCT, seven MRI sessions showed increased gadoteridol contrast enhancement on T1-weighted scans coupled with low rCBV without significant differences between contrast agents (p = 0.9). Based on post-gadoteridol T1-weighted scans, DSC-MRI, and clinical presentation, four patterns of response to RCT were observed: regression, pseudoprogression, true progression, and mixed response. Conclusion: We conclude that DSC-MRI with a blood pool agent such as ferumoxytol may provide a better monitor of tumor rCBV than DSC-MRI with gadoteridol. Lesions demonstrating increased enhancement on T1-weighted MRI coupled with low ferumoxytol rCBV are likely exhibiting pseudoprogression, whereas high rCBV with ferumoxytol is a better marker than gadoteridol for determining active tumor. These interesting pilot observations suggest that ferumoxytol may differentiate tumor progression from pseudoprogression and warrant further investigation.

  7. Field enhancement of nonreciprocal electromagnetic wave supported by magnetic surface plasmon.

    PubMed

    Poo, Yin; Liu, Shiyang; Xiao, Chao; Wu, Rui-Xin; Chen, Ping

    2014-11-01

    At the zigzag edge of a magnetic photonic crystal with honeycomb lattice, the nonreciprocal surface modes (NSMs) could appear below the magnetic surface plasmon (MSP) frequency. The NSMs possess very flat slopes outside the light line, which is strikingly different from the nearly linear dispersion curve just above the MSP frequency and results in strong confinement and enhancement of the electromagnetic field. Particularly, an enhancement over 100 times in magnetic field is achieved because of the strong magnetic response arising from the MSP resonance. In addition, the branch of double-valued NSM dispersion curve provides zero group velocity away from the Brillouin zone boundary. PMID:25401915

  8. Radiation necrosis of the optic chiasm, optic tract, hypothalamus, and upper pons after radiotherapy for pituitary adenoma, detected by gadolinium-enhanced, T1-weighted magnetic resonance imaging: Case report

    SciTech Connect

    Tachibana, O.; Yamaguchi, N.; Yamashima, T.; Yamashita, J. )

    1990-10-01

    A 26-year-old woman was treated for a prolactin secreting pituitary adenoma by surgery and radiotherapy (5860 rads). Fourteen months later, she developed right hemiparesis and dysarthria. A T1-weighted magnetic resonance imaging scan using gadolinium contrast showed a small, enhanced lesion in the upper pons. Seven months later, she had a sudden onset of loss of vision, and radiation optic neuropathy was diagnosed. A T1-weighted magnetic resonance imaging scan showed widespread gadolinium-enhanced lesions in the optic chiasm, optic tract, and hypothalamus. Magnetic resonance imaging is indispensable for the early diagnosis of radiation necrosis, which is not visualized by radiography or computed tomography.

  9. Novel light-weight, high-performance anode-supported microtubular solid oxide fuel cells with an active anode functional layer

    NASA Astrophysics Data System (ADS)

    Liu, Tong; Wang, Yao; Ren, Cong; Fang, Shumin; Mao, Yating; Chen, Fanglin

    2015-10-01

    Influence of the air-gap, the distance from the tube-in-orifice spinneret to the upper surface of the external coagulant bath during the extrusion/phase-inversion process, on the microstructure of nickel - yttria-stabilized zirconia (Ni-YSZ) hollow fibers has been systematically studied. When the air-gap is 0 cm, the obtained Ni-YSZ hollow fiber has a sandwich microstructure. However, when the air-gap is increased to 15 cm, a bi-layer Ni-YSZ hollow fiber consisting of a thin layer with small pores and a thick support with highly porous fingerlike macrovoids has been achieved. The output power density of microtubular solid oxide fuel cells (MT-SOFCs) with a cell configuration of Ni-YSZ/YSZ/YSZ-LSM increases from 594 mW cm-2 for the cells with the Ni-YSZ anode of sandwich microstructure to 832 mW cm-2 for the cells with the Ni-YSZ anode of bi-layer microstructure at 750 °C, implying that to achieve the same output power density, the weight of the cells with the bi-layer anode support can be reduced to 41.5% compared with that of the cells with the sandwich anode support. Thermal-cycling test shows no obvious degradation on the open-circuit-voltage (OCV), indicating that the MT-SOFCs have robust resistance to thermal cycling.

  10. Magnetic Silica-Supported Ruthenium Nanoparticles: An Efficient Catalyst for Transfer Hydrogenation of Carbonyl Compounds

    EPA Science Inventory

    One-pot synthesis of ruthenium nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium nano particles immobilization; the hydration of nitriles and transfer hydrogenation of carbonyl compounds occurs in hi...

  11. Influences of Changes in the Level of Support and Walking Speed on the H Reflex of the Soleus Muscle and Circulatory Dynamics on Body Weight-supported Treadmill Training: Investigation in Healthy Adults

    PubMed Central

    Watanabe, Shinichi; Oya, Yosuke; Iwata, Jun; Someya, Fujiko

    2014-01-01

    [Purpose] To investigate the therapeutic usefulness of treadmill walking using a body weight support device (BWS), changes in circulatory dynamics and muscle activities with various levels of support were investigated. [Subjects and Methods] The subjects were divided into 3 groups: 20% BWS, 40% BWS, and full body weight (FBW). The subjects walked at maximum and normal speeds. Under each condition, H and M waves and skin temperature before and after walking and changes in the heart rate during walking were measured. [Results] The heart rate continued to increase after 3 minutes of FBW at the maximum walking speed, but a steady state was reached after 3 minutes under the other walking conditions. Regarding skin temperature, no significant difference from that at rest was noted 30 minutes after walking at the normal speed, but it was significantly higher than that at rest at 30 minutes after walking at the maximum speed. The H/M ratio was significantly higher after walking at the maximum walking speed in the FBW and 20% BWS groups compared with the 40% BWS groups. [Conclusion] Treatment with 40% BWS at the maximum walking speed was safe for the circulatory system and may be effective in elevating the skin temperature for a prolonged period compared with the effects of the other walking conditions at normal speed. PMID:25276013

  12. Postmortem Study of Validation of Low Signal on Fat-Suppressed T1-Weighted Magnetic Resonance Imaging as Marker of Lipid Core in Middle Cerebral Artery Atherosclerosis

    PubMed Central

    Yang, Wen-Jie; Zhao, Hai-Lu; Niu, Chun-Bo; Zhang, Bing; Xu, Yun; Wong, Ka-Sing; Ng, Ho-Keung

    2016-01-01

    Background and Purpose— High signal on T1-weighted fat-suppressed images in middle cerebral artery plaques on ex vivo magnetic resonance imaging was verified to be intraplaque hemorrhage histologically. However, the underlying plaque component of low signal on T1-weighted fat-suppressed images (LST1) has never been explored. Based on our experience, we hypothesized that LST1 might indicate the presence of lipid core within intracranial plaques. Methods— 1.5 T magnetic resonance imaging was performed in the postmortem brains to scan the cross sections of bilateral middle cerebral arteries. Then middle cerebral artery specimens were removed for histology processing. LST1 presence was identified on magnetic resonance images, and lipid core areas were measured on the corresponding histology sections. Results— Total 76 middle cerebral artery locations were included for analysis. LST1 showed a high specificity (96.9%; 95% confidence interval, 82.0%–99.8%) but a low sensitivity (38.6%; 95% confidence interval, 24.7%–54.5%) for detecting lipid core of all areas. However, the sensitivity increased markedly (81.2%; 95% confidence interval, 53.7%–95.0%) when only lipid cores of area ≥0.80 mm2 were included. Mean lipid core area was 5× larger in those with presence of LST1 than in those without (1.63±1.18 mm2 versus 0.32±0.31 mm2; P=0.003). Conclusions— LST1 is a promising imaging biomarker of identifying intraplaque lipid core, which may be useful to distinguish intracranial atherosclerotic disease from other intracranial vasculopathies and to assess plaque vulnerability for risk stratification of patients with intracranial atherosclerotic disease. In vivo clinical studies are required to explore the correlation between LST1 and clinical outcomes of patients with intracranial atherosclerotic disease. PMID:27462119

  13. Multiplex protein pattern unmixing using a non-linear variable-weighted support vector machine as optimized by a particle swarm optimization algorithm.

    PubMed

    Yang, Qin; Zou, Hong-Yan; Zhang, Yan; Tang, Li-Juan; Shen, Guo-Li; Jiang, Jian-Hui; Yu, Ru-Qin

    2016-01-15

    Most of the proteins locate more than one organelle in a cell. Unmixing the localization patterns of proteins is critical for understanding the protein functions and other vital cellular processes. Herein, non-linear machine learning technique is proposed for the first time upon protein pattern unmixing. Variable-weighted support vector machine (VW-SVM) is a demonstrated robust modeling technique with flexible and rational variable selection. As optimized by a global stochastic optimization technique, particle swarm optimization (PSO) algorithm, it makes VW-SVM to be an adaptive parameter-free method for automated unmixing of protein subcellular patterns. Results obtained by pattern unmixing of a set of fluorescence microscope images of cells indicate VW-SVM as optimized by PSO is able to extract useful pattern features by optimally rescaling each variable for non-linear SVM modeling, consequently leading to improved performances in multiplex protein pattern unmixing compared with conventional SVM and other exiting pattern unmixing methods. PMID:26592652

  14. Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke

    PubMed Central

    Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

    2015-01-01

    [Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke. PMID:26157272

  15. Assessment of Myocardial Fibrosis in Mice Using a T2*-Weighted 3D Radial Magnetic Resonance Imaging Sequence

    PubMed Central

    van Nierop, Bastiaan J.; Bax, Noortje A. M.; Nelissen, Jules L.; Arslan, Fatih; Motaal, Abdallah G.; de Graaf, Larry; Zwanenburg, Jaco J. M.; Luijten, Peter R.; Nicolay, Klaas; Strijkers, Gustav J.

    2015-01-01

    Background Myocardial fibrosis is a common hallmark of many diseases of the heart. Late gadolinium enhanced MRI is a powerful tool to image replacement fibrosis after myocardial infarction (MI). Interstitial fibrosis can be assessed indirectly from an extracellular volume fraction measurement using contrast-enhanced T1 mapping. Detection of short T2* species resulting from fibrotic tissue may provide an attractive non-contrast-enhanced alternative to directly visualize the presence of both replacement and interstitial fibrosis. Objective To goal of this paper was to explore the use of a T2*-weighted radial sequence for the visualization of fibrosis in mouse heart. Methods C57BL/6 mice were studied with MI (n = 20, replacement fibrosis), transverse aortic constriction (TAC) (n = 18, diffuse fibrosis), and as control (n = 10). 3D center-out radial T2*-weighted images with varying TE were acquired in vivo and ex vivo (TE = 21 μs-4 ms). Ex vivo T2*-weighted signal decay with TE was analyzed using a 3-component model. Subtraction of short- and long-TE images was used to highlight fibrotic tissue with short T2*. The presence of fibrosis was validated using histology and correlated to MRI findings. Results Detailed ex vivo T2*-weighted signal analysis revealed a fast (T2*fast), slow (T2*slow) and lipid (T2*lipid) pool. T2*fast remained essentially constant. Infarct T2*slow decreased significantly, while a moderate decrease was observed in remote tissue in post-MI hearts and in TAC hearts. T2*slow correlated with the presence of diffuse fibrosis in TAC hearts (r = 0.82, P = 0.01). Ex vivo and in vivo subtraction images depicted a positive contrast in the infarct co-localizing with the scar. Infarct volumes from histology and subtraction images linearly correlated (r = 0.94, P<0.001). Region-of-interest analysis in the in vivo post-MI and TAC hearts revealed significant T2* shortening due to fibrosis, in agreement with the ex vivo results. However, in vivo contrast on

  16. Magnetic single-walled carbon nanotubes as efficient drug delivery nanocarriers in breast cancer murine model: noninvasive monitoring using diffusion-weighted magnetic resonance imaging as sensitive imaging biomarker

    PubMed Central

    Al Faraj, Achraf; Shaik, Abjal Pasha; Shaik, Asma Sultana

    2015-01-01

    allowed their sensitive noninvasive diagnosis using susceptibility-weighted MRI and their magnetic targeting using an externally applied magnet. Conclusion Enhanced therapeutic efficacy of DOX delivered through antibody-conjugated magnetic SWCNTs was achieved. Further, the superiority of apparent diffusion coefficient measurements using diffusion-weighted MRI was found to be a sensitive imaging biomarker for assessment of treatment-induced changes. PMID:25565811

  17. The Use of Susceptibility-Weighted Magnetic Resonance Imaging to Characterize the Safety Window of Focused Ultrasound Exposure for Localized Blood—Brain-Barrier Disruption

    NASA Astrophysics Data System (ADS)

    Liu, Hao-Li; Hsu, Po-Hong; Wai, Yau-Yau; Chen, Jin-Chung; Yen, Tzu-Chen; Wang, Jiun-Jie

    2009-04-01

    High-intensity focused ultrasound has been discovered to be able to locally and reversibly increase the permeability of the blood—brain barrier (BBB), which can be detected using magnetic resonance imaging (MRI). However, side effects such as microhemorrhage, erythrocyte extravasations, or even extensive hemorrhage can also occur. Although current contrast-enhanced T1-weighted MRI can be used to detect the changes in BBB permeability, its efficacy in detecting tissue hemorrhage after focused-ultrasound sonication remains limited. The purpose of this study was to determine the feasibility of using MR susceptibility-weighted imaging (SWI) to identify tissue hemorrhage associated with the process of BBB permeability increase and characterize the safety window of acoustic pressure level. Brains of 42 Sprague-Dawley rats were subjected to 107 sonications either unilaterally or bilaterally. Contrast-enhanced T1-weighted images, together with SWI were performed. Tissue damage and hemorrhage were analyzed histologically with light microscopy and staining by Evan's blue, HE staining as well as TUNEL staining. Our results showed that contrast-enhanced T1 weighted imaging is sensitive to the presence of the BBB disrupture, but was unable to differentiate from extensive tissue damage such as hemorrhage. Also, SWI proved to be a superior tool for the realtime monitoring of the presence of hemorrhage, which is essential to the clinical concerns. The safety operation window in vivo in our study indicated a pressure of 0.78 to 1.1 MPa. to increase the BBB permeability successfully without hemorrhage. Potential applications such as drug delivery in the brain might be benefited.

  18. Predicting Outcome of Patients with High-grade Gliomas After Radiotherapy using Quantitative Analysis of T1-weighted Magnetic Resonance Imaging

    SciTech Connect

    Tsien, Christina . E-mail: ctsien@umich.edu; Gomez-Hassan, Diana; Chenevert, Thomas L.; Lee, Julia; Lawrence, Theodore; Haken, Randall K. ten; Junck, Larry R.; Ross, Brian; Cao Yue

    2007-04-01

    Purpose: The aim of this study was to test the hypothesis that measuring quantitative changes in signal intensity early after radiotherapy (RT) in the contrast-enhancing tumor rim and nonenhancing core may be a noninvasive marker of early treatment response in patients with high-grade gliomas. Methods and Materials: Twenty patients with high-grade gliomas had magnetic resonance imaging (MRI) performed 1 week before RT, during Weeks 1 and 3 of RT, and every 1 to 3 months after RT as part of a clinical prospective study. Regions of interest (ROI) including contrast-enhancing rim, and the nonenhancing core were defined automatically based on a calculated image of post- to precontrast T1-weighted MRI. Pretreatment T1-weighted MRI signal intensity changes were compared with Weeks 1 and 3 RT and 1 and 3 months post-RT MRI. Clinical and MRI parameters were then tested for prediction of overall survival. Results: Regional T1-weighted signal intensity changes in both the contrast-enhancing rim and the nonenhancing core were observed in all patients during Week 1 and Week 3 of RT. Imaging parameters including signal intensity change within the nonenhancing core after Weeks 1 to 2 RT (p = 0.004), Weeks 3 to 4 RT (p = 0.002) and 1 month after completion of RT (p 0.002) were predictive of overall survival. Using multivariate analysis including RTOG recursive partitioning analysis (RPA) and signal intensity change, only the signal intensity change in the nonenhancing core at 1 month after RT (p = 0.01) retained significance. Conclusion: Quantitative measurements of T1-weighted MRI signal intensity changes in the nonenhancing tumor core (using ratios of pre-post values) may provide valuable information regarding early response during treatment and improve our ability to predict posttreatment outcome.

  19. Thermal and structural performance of a single tube support post for the Superconducting Super Collider dipole magnet cryostat

    SciTech Connect

    Boroski, W.N.; Nicol, T.H.; Ruschman, M.K.; Schoo, C.J.

    1993-07-01

    The reentrant support post currently incorporated in the Superconducting Super Collider (SSC) dipole cryostat has been shown to meet the structural and thermal requirements of the cryostat, both in prototype magnet assemblies and through component testing. However, the reentrant post design has two major drawbacks: tight dimensional control on all components, and cost driven by these tolerance constraints and a complex assembly procedure. A single tube support post has been developed as an alternative to the reentrant post design. Several prototype assemblies have been fabricated and subjected to structural testing. Compressive, tensile, and bending forces were applied to each assembly with deflection measured at several locations. A prototype support post has also been thermally evaluated in a heat leak measurement facility. Heat load to 4.2 K was measured with the intermediate post intercept operating at various temperatures while thermometers positioned along the conductive path of the post mapped thermal gradients. Results from these measurements indicate the single tube support post meets the design criteria for the SSC dipole magnet cryostat support system.

  20. Determination of the magnetic susceptibility and the magentic polarization of weights by means of the susceptometer method

    NASA Astrophysics Data System (ADS)

    Quiroga, A.; Bermudez, A.; Kornblit, F.; Garcia, F.; Fang, H.; Caceres, J.; Peña, L. M.; Ramos, O.; Viaggio, A.; Santo, C.

    2016-01-01

    This report summarizes the results of a SIM comparison of magentic properties by means of the susceptometer method. It was carried out by seven SIM laboraories and BIPM. Five standards have been circulated: two OIML weights class E2, two of them with nominal value 1 kg and two of them with nominal value 2 g, and a steel disk. Most of the results were consistent with each other. This final report shows the degree of equivalence achieved by the participants Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  1. A decision support system to improve medical diagnosis using a combination of k-medoids clustering based attribute weighting and SVM.

    PubMed

    Peker, Musa

    2016-05-01

    The use of machine learning tools has become widespread in medical diagnosis. The main reason for this is the effective results obtained from classification and diagnosis systems developed to help medical professionals in the diagnosis phase of diseases. The primary objective of this study is to improve the accuracy of classification in medical diagnosis problems. To this end, studies were carried out on 3 different datasets. These datasets are heart disease, Parkinson's disease (PD) and BUPA liver disorders. Key feature of these datasets is that they have a linearly non-separable distribution. A new method entitled k-medoids clustering-based attribute weighting (kmAW) has been proposed as a data preprocessing method. The support vector machine (SVM) was preferred in the classification phase. In the performance evaluation stage, classification accuracy, specificity, sensitivity analysis, f-measure, kappa statistics value and ROC analysis were used. Experimental results showed that the developed hybrid system entitled kmAW + SVM gave better results compared to other methods described in the literature. Consequently, this hybrid intelligent system can be used as a useful medical decision support tool. PMID:27000777

  2. Preoperative CT versus diffusion weighted magnetic resonance imaging of the liver in patients with rectal cancer; a prospective randomized trial

    PubMed Central

    Løgager, Vibeke B.; Skjoldbye, Bjørn; Møller, Jakob M.; Lorenzen, Torben; Rasmussen, Vera L.; Thomsen, Henrik S.; Mollerup, Talie H.; Okholm, Cecilie; Rosenberg, Jacob

    2016-01-01

    Introduction. Colorectal cancer is one of the most frequent cancers in the world and liver metastases are seen in up to 19% of patients with colorectal cancers. Detection of liver metastases is not only vital for sufficient treatment and survival, but also for a better estimation of prognosis. The aim of this study was to evaluate the feasibility of diffusion weighted MRI of the liver as part of a combined MR evaluation of patients with rectal cancers and compare it with the standard preoperative evaluation of the liver with CT. Methods. Consecutive patients diagnosed with rectal cancers were asked to participate in the study. Preoperative CT and diffusion weighted MR (DWMR) were compared to contrast enhanced laparoscopic ultrasound (CELUS). Results. A total of 35 patients were included, 15 patients in Group-1 having the standard CT evaluation of the liver and 20 patients in Group-2 having the standard CT evaluation of the liver and DWMR of the liver. Compared with CELUS, the per-patient sensitivity/specificity was 50/100% for CT, and for DWMR: 100/94% and 100/100% for Reader 1 and 2, respectively. The per-lesion sensitivity of CT and DWMR were 17% and 89%, respectively compared with CELUS. Furthermore, one patient had non-resectable metastases after DWMR despite being diagnosed with resectable metastases after CT. Another patient was diagnosed with multiple liver metastases during CELUS, despite a negative CT-scan. Discussion. DWMR is feasible for preoperative evaluation of liver metastases. The current standard preoperative evaluation with CT-scan results in disadvantages like missed metastases and futile operations. We recommend that patients with rectal cancer, who are scheduled for MR of the rectum, should have a DWMR of the liver performed at the same time. PMID:26793420

  3. Role of Diffusion-weighted Imaging in Acute Stroke Management using Low-field Magnetic Resonance Imaging in Resource-limited Settings

    PubMed Central

    Okorie, Chinonye K; Ogbole, Godwin I; Owolabi, Mayowa O; Ogun, Olufunmilola; Adeyinka, Abiodun; Ogunniyi, Adesola

    2015-01-01

    A variety of imaging modalities exist for the diagnosis of stroke. Several studies have been carried out to ascertain their contribution to the management of acute stroke and to compare the benefits and limitations of each modality. Diffusion-weighted imaging (DWI) has been described as the optimal imaging technique for diagnosing acute ischemic stroke, yet limited evidence is available on the value of DWI in the management of ischemic stroke with low-field magnetic resonance (MR) systems. Although high-field MR imaging (MRI) is desirable for DWI, low-field scanners provide an acceptable clinical compromise which is of importance to developing countries posed with the challenge of limited availability of high-field units. The purpose of this paper was to systematically review the literature on the usefulness of DWI in acute stroke management with low-field MRI scanners and present the experience in Nigeria. PMID:26709342

  4. Improved Mitochondrial and Methylglyoxal-Related Metabolisms Support Hyperproliferation Induced by 50 Hz Magnetic Field in Neuroblastoma Cells.

    PubMed

    Falone, Stefano; Santini, Silvano; di Loreto, Silvia; Cordone, Valeria; Grannonico, Marta; Cesare, Patrizia; Cacchio, Marisa; Amicarelli, Fernanda

    2016-09-01

    Extremely low frequency magnetic fields (ELF-MF) are common environmental agents that are suspected to promote later stages of tumorigenesis, especially in brain-derived malignancies. Even though ELF magnetic fields have been previously linked to increased proliferation in neuroblastoma cells, no previous work has studied whether ELF-MF exposure may change key biomolecular features, such as anti-glycative defence and energy re-programming, both of which are currently considered as crucial factors involved in the phenotype and progression of many malignancies. Our study investigated whether the hyperproliferation that is induced in SH-SY5Y human neuroblastoma cells by a 50 Hz, 1 mT ELF magnetic field is supported by an improved defense towards methylglyoxal (MG), which is an endogenous cancer-static and glycating α-oxoaldehyde, and by rewiring of energy metabolism. Our findings show that not only the ELF magnetic field interfered with the biology of neuron-derived malignant cells, by de-differentiating further the cellular phenotype and by increasing the proliferative activity, but also triggered cytoprotective mechanisms through the enhancement of the defense against MG, along with a more efficient management of metabolic energy, presumably to support the rapid cell outgrowth. Intriguingly, we also revealed that the MF-induced bioeffects took place after an initial imbalance of the cellular homeostasis, which most likely created a transient unstable milieu. The biochemical pathways and molecular targets revealed in this research could be exploited for future approaches aimed at limiting or suppressing the deleterious effects of ELF magnetic fields. J. Cell. Physiol. 231: 2014-2025, 2016. © 2016 Wiley Periodicals, Inc. PMID:26757151

  5. Differential Diagnosis of Axillary Inflammatory and Metastatic Lymph Nodes in Rabbit Models by Using Diffusion-Weighted Imaging: Compared with Conventional Magnetic Resonance Imaging

    PubMed Central

    Liao, Qian; Zhang, Yunting; Yu, Chunshui; Bai, Renju; Sun, Haoran

    2012-01-01

    Objective This experiment aims to determine the diagnostic value of diffusion-weighted imaging (DWI) in the differentiation of axillary inflammatory lymph nodes from metastatic lymph nodes in rabbit models in comparison with conventional magnetic resonance imaging (MRI). Materials and Methods Conventional MRI and DWI were performed at 4 weeks after successful inoculation into the forty female New Zealand white rabbits' mammary glands. The size-based and signal-intensity-based criteria and the relative apparent diffusion coefficient (rADC) value were compared between the axillary inflammatory lymph nodes and metastatic lymph nodes, with histopathological findings as the reference standard. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of the aforementioned criteria and rADC value in differentiating the axillary inflammatory lymph nodes from metastatic lymph nodes. Results Thirty-two axillary inflammatory lymph nodes and 46 metastatic ones were successfully isolated and taken into pathological analysis. The differences of the aforementioned criteria between the two groups were not statistically significant (p > 0.05). However, the rADC value of the inflammatory lymph nodes (0.9 ± 0.14) was higher than that of metastatic ones (0.7 ± 0.18), with significant difference (p = 0.016). When the rADC value was chosen as 0.80, the area under the ROC curve is greater than all other criteria, and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for differentiating two groups were 86.2%, 79.3%, 81.2%, 84.2%, and 85.6%, respectively. Conclusion Diffusion-weighted imaging is a promising new technique for differentiating axillary inflammatory lymph nodes from metastatic lymph nodes. Compared with routine magnetic resonance sequences, DWI could provide more useful physiological and functional information for diagnosis. PMID:22778568

  6. Anisotropic diffusion of metabolites in peripheral nerve using diffusion weighted magnetic resonance spectroscopy at ultra-high field

    NASA Astrophysics Data System (ADS)

    Ellegood, Jacob; McKay, Ryan T.; Hanstock, Chris C.; Beaulieu, Christian

    2007-01-01

    Although the diffusivity and anisotropy of water has been investigated thoroughly in ordered axonal systems (i.e., nervous tissue), there have been very few studies on the directional dependence of diffusion of metabolites. In this study, the mean apparent diffusion coefficient (Trace/3 ADC) and fractional anisotropy (FA) values of the intracellular metabolites N-acetyl aspartate (NAA), creatine and phosphocreatine (tCr), choline (Cho), taurine (Tau), and glutamate and glutamine (Glx) were measured parallel and perpendicular to the length of excised frog sciatic nerve using a water suppressed, diffusion-weighted, spin-echo pulse sequence at 18.8 T. The degree of anisotropy (FA) of NAA (0.41 ± 0.09) was determined to be less than tCr (0.59 ± 0.07) and Cho (0.61 ± 0.11), which is consistent with previously reported human studies of white matter. In contrast, Glx diffusion was found to be almost isotropic with an FA value of 0.20 ± 0.06. The differences of FA between the metabolites is most likely due to their differing micro-environments and could be beneficial as an indicator of compartment specific changes with disease, information not readily available with water diffusion.

  7. Diffusion-Weighted Magnetic Resonance Application in Response Prediction before, during, and after Neoadjuvant Radiochemotherapy in Primary Rectal Cancer Carcinoma

    PubMed Central

    Musio, Daniela; De Felice, Francesca; Magnante, Anna Lisa; Rengo, Marco; Redler, Adriano; Laghi, Andrea; Raffetto, Nicola; Tombolini, Vincenzo

    2013-01-01

    Introduction. Our interest was to monitor treatment response using ADC value to predict response of rectal tumour to preoperative radiochemotherapy. Materials and Methods. Twenty-two patients were treated with long course of radiochemotherapy, followed by surgery. Patients were examined by diffusion-weighted imaging MRI at three-time points (prior, during, and after radiochemotherapy) and were classified as responders and nonresponders. Results. A statistical significant correlation was found between preradiochemotherapy ADC values and during treatment ADC values, in responders (F = 21.50, P value <0.05). An increase in ADC value during treatment was predictive of at least a partial response. Discussion. Response of tumour to neoadjuvant therapy cannot be easily evaluated, and such capability might be of great importance in clinical practice, because the number of irradiated and operated patients may be superior to the number of who will really benefit from this multimodal treatment. A reliable prediction of the final clinical TN stage would allow radiotherapist to adapt multidisciplinary approach to a less invasive management, sparing surgical procedure in responder patients or even allowing an early surgery in nonresponders, which would significantly reduce radiochemotherapy related toxicity. Conclusion. Early evaluation of response during neoadjuvant radiochemotherapy treatment shows great promise to predict tumour response. PMID:23936841

  8. Quantitative Evaluation of Growth Plates around the Knees of Adolescent Soccer Players by Diffusion-Weighted Magnetic Resonance Imaging

    PubMed Central

    Krajnc, Zmago; Rupreht, Mitja; Drobnič, Matej

    2015-01-01

    Purpose. To quantitatively evaluate growth plates around the knees in adolescent soccer players utilizing the diffusion-weighted MR imaging (DWI). Methods. The knees and adjacent growth plates of eleven 14-year-old male soccer players were evaluated by MRI before (end of season's summer break) and after two months of intense soccer training. MRI evaluation was conducted in coronal plane by PD-FSE and DWI. All images were screened for any major pathological changes. Later, central growth plate surface area (CGPSA) was measured and the apparent diffusion coefficient (ADC) values were calculated in two most central coronal slices divided into four regions: distal femur medial (DFM), distal femur lateral (DFL), proximal tibia medial (PTM), and proximal tibia lateral (PTL). Results. No gross pathology was diagnosed on MRI. CGPSA was not significantly reduced: DFM 278 versus 272, DFL 265 versus 261, PTM 193 versus 192, and PTL 214 versus 210. ADC decrease was statistically significant only for PTM: DFM 1.27 versus 1.22, DFL 1.37 versus 1.34, PTM 1.13 versus 1.03 (p = 0.003), and PTL 1.28 versus 1.22. Conclusions. DWI measurements indicate increased cellularity in growth plates around knees in footballers most prominent in PTM after intense training. No detectable differences on a standard PD-FSE sequence were observed. PMID:26693482

  9. Gd (III) complex conjugate of low-molecular-weight chitosan as a contrast agent for magnetic resonance/fluorescence dual-modal imaging.

    PubMed

    Huang, Yan; Boamah, Peter Osei; Gong, Jianbo; Zhang, Qi; Hua, Mingqing; Ye, Yuzhen

    2016-06-01

    The fusion of molecular and anatomical modalities facilitates more reliable and accurate detection in clinic. In this work, we prepared gadolinium (III) complex Gd-DTPA-FITC-CS11 with magnetic resonance (MR) and fluorescence dual-modal imaging modalities. Gd-DTPA-FITC-CS11 consisted of fluorescein isothiocyanate and low-molecular-weight chitosan (CS11) units conjugated with gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Gd-DTPA-FITC-CS11 exhibited a higher longitudinal relaxivity (14.09mM(-1)s(-1)) than the clinical Gd-DTPA (3.85mM(-1)s(-1)). T1-weighted MR contrast enhancement was also demonstrated the comparability to Gd-DTPA at lower dosage. The binding with bovine serum albumin (BSA) was investigated. The fluorescence of BSA in the presence of Gd-DTPA-FITC-CS11 was weakened due to static quenching mechanism. The conformation of BSA was slightly changed but α-helix was dominant. The binding was entropy-driven and spontaneous and the main contribution was hydrophobic interaction. Our results suggested the potential of Gd-DTPA-FITC-CS11 as an MR/fluorescence dual-modal imaging contrast agent in improving the diagnostic sensitivity and accuracy. PMID:27083371

  10. Diagnostic accuracy of fat-saturated T2-weighted magnetic resonance imaging in the diagnosis of perforation of the articular disc of the temporomandibular joint.

    PubMed

    Yura, Shinya; Nobata, Koji; Shima, Tsuyoshi

    2012-06-01

    The accuracy of diagnosing a perforation of the articular disc of the temporomandibular joint (TMJ) is poor with conventional magnetic resonance imaging (MRI). We recently reported that a high signal-intensity area is usually found on fat-saturated T2-weighted MRI in the joint space between the articular disc and cartilage surface in joints in which the disc is displaced. A discrete image with an area of high signal-intensity in the middle of the articular disc may indicate perforation or rupture. The purpose of this study was to compare the accuracy of diagnosis of a perforated articular disc by fat-saturated T2-weighted MRI with that of arthroscopy. We studied 50 joints in 50 patients with closed lock of the TMJ who were examined with MRI and then by arthroscopy using an ultra-thin arthroscope. The agreement between the two methods of diagnosis was assessed using the κ coefficient. Evidence of perforation of the disc on MRI and arthroscopically was found in the same 7 joints; there was complete concordance (κ=1.00, p<0.001). The accuracy of diagnosis of perforation of a disc by fat-saturated MRI was therefore the same as that by arthroscopy using an ultra-thin arthroscope. PMID:21723011

  11. Molecular weight distributions of irradiated siloxane-based elastomers: A complementary study by statistical modeling and multiple quantum nuclear magnetic resonance

    SciTech Connect

    Dinh, L. N.; Mayer, B. P.; Maiti, A.; Chinn, S. C.; Maxwell, R. S.

    2011-05-01

    The statistical methodology of population balance (PB) has been applied in order to predict the effects of cross-linking and chain-scissioning induced by ionizing radiation on the distribution of molecular weight between cross-links (MWBC) of a siloxane-based elastomer. Effective molecular weight distributions were extracted from the quantification of residual dipolar couplings via multiple quantum nuclear magnetic resonance (MQ-NMR) measurements and are taken to reflect actual MWBC distributions. The PB methodology is then applied to the unirradiated MWBC distribution and considers both chain-scissioning and the possibility of the formation of three types of cross-links: random recombination of scissioned-chain ends (end-linking), random covalent bonds of free radicals on scissioned-chain ends (Y-cross-linking), and the formation of random cross-links from free radicals on side groups (H-cross-linking). The qualitative agreement between the statistical modeling approach and the NMR data confirms that it is possible to predict trends for the evolution of the distribution of MWBC of polymers under irradiation. The approach described herein can also discern heterogeneities in radiation effects in different structural motifs in the polymer network.

  12. Relationship between Proton Magnetic Resonance Spectroscopy of Frontoinsular Gray Matter and Neurodevelopmental Outcomes in Very Low Birth Weight Children at the Age of 4

    PubMed Central

    Herman-Sucharska, Izabela; Urbanik, Andrzej; Klimek, Małgorzata; Karcz, Paulina; Dutkowska, Grażyna; Nitecka, Magdalena; Kwinta, Przemko

    2016-01-01

    Very low birth weight is associated with long term neurodevelopmental complications. Macroscopic brain abnormalities in prematurity survivors have been investigated in several studies. However, there is limited data regarding local cerebral metabolic status and neurodevelopmental outcomes. The purpose of this study was to characterize the relationship between proton magnetic resonance spectra in basal ganglia, frontal white matter and frontoinsular gray matter, neurodevelopmental outcomes assessed with the Leiter scale and the Developmental Test of Visual Perception and selected socioeconomic variables in a cohort of very low birth weight children at the age of four. Children were divided in three groups based on the severity of neurodevelopmental impairment. There were no differences in spectroscopy in basal ganglia and frontal white matter between the groups. Lower concentrations of N-acetylaspartate (NAA), choline (Cho) and myoinositol (mI) were observed in the frontoinsular cortex of the left hemisphere in children with neurodevelopmental impairment compared to children with normal neurodevelopmental outcomes. Higher parental education, daycare attendance and breastfeeding after birth were associated with more favorable neurodevelopmental prognosis, whereas rural residence was more prevalent in children with moderate and severe impairment. Our study demonstrates the role of long term neurometabolic disruption in the left frontoinsular cortex and selected socioeconomic variables in determination of neurodevelopmental prognosis in prematurity survivors. PMID:27223474

  13. Noise reduction of nuclear magnetic resonance (NMR) transversal data using improved wavelet transform and exponentially weighted moving average (EWMA)

    NASA Astrophysics Data System (ADS)

    Ge, Xinmin; Fan, Yiren; Li, Jiangtao; Wang, Yang; Deng, Shaogui

    2015-02-01

    NMR logging and core NMR signals acts as an effective way of pore structure evaluation and fluid discrimination, but it is greatly contaminated by noise for samples with low magnetic resonance intensity. Transversal relaxation time (T2) spectrum obtained by inversion of decay signals intrigued by Carr-Purcell-Meiboom-Gill (CPMG) sequence may deviate from the truth if the signal-to-noise ratio (SNR) is imperfect. A method of combing the improved wavelet thresholding with the EWMA is proposed for noise reduction of decay data. The wavelet basis function and decomposition level are optimized in consideration of information entropy and white noise estimation firstly. Then a hybrid threshold function is developed to avoid drawbacks of hard and soft threshold functions. To achieve the best thresholding values of different levels, a nonlinear objective function based on SNR and mean square error (MSE) is constructed, transforming the problem to a task of finding optimal solutions. Particle swarm optimization (PSO) is used to ensure the stability and global convergence. EWMA is carried out to eliminate unwanted peaks and sawtooths of the wavelet denoised signal. With validations of numerical simulations and experiments, it is demonstrated that the proposed approach can reduce the noise of T2 decay data perfectly.

  14. Diffusion-Weighted Magnetic Resonance Imaging Early After Chemoradiotherapy to Monitor Treatment Response in Head-and-Neck Squamous Cell Carcinoma

    SciTech Connect

    Vandecaveye, Vincent; Dirix, Piet; De Keyzer, Frederik; Op de Beeck, Katya; Vander Poorten, Vincent; Hauben, Esther; Lambrecht, Maarten; Nuyts, Sandra; Hermans, Robert

    2012-03-01

    Purpose: To evaluate diffusion-weighted imaging (DWI) for assessment of treatment response in head and neck squamous cell carcinoma (HNSCC) three weeks after the end of chemoradiotherapy (CRT). Methods and Materials: Twenty-nine patients with HNSCC underwent magnetic resonance imaging (MRI) prior to and 3 weeks after CRT, including T{sub 2}-weighted and pre- and postcontrast T{sub 1}-weighted sequences and an echo-planar DWI sequence with six b values (0 to 1,000 s/mm{sup 2}), from which the apparent diffusion coefficient (ADC) was calculated. ADC changes 3 weeks posttreatment compared to baseline ( Increment ADC) between responding and nonresponding primary lesions and adenopathies were correlated with 2 years locoregional control and compared with a Mann-Whitney test. In a blinded manner, the Increment ADC was compared to conventional MRI 3 weeks post-CRT and the routinely implemented CT, on average 3 months post-CRT, which used size-related and morphological criteria. Positive and negative predictive values (PPV and NPV, respectively) were compared between the Increment ADC and anatomical imaging. Results: The Increment ADC of lesions with later tumor recurrence was significantly lower than lesions with complete remission for both primary lesions (-2.3% {+-} 0.3% vs. 80% {+-} 41%; p < 0.0001) and adenopathies (19.9% {+-} 32% vs. 63% {+-} 36%; p = 0.003). The Increment ADC showed a PPV of 89% and an NPV of 100% for primary lesions and a PPV of 70% and an NPV of 96% for adenopathies per neck side. DWI improved PPV and NPV compared to anatomical imaging. Conclusion: DWI with the Increment ADC 3 weeks after concluding CRT for HNSCC allows for early assessment of treatment response.

  15. MAGNETIC LIQUID DEFORMABLE MIRRORS FOR ASTRONOMICAL APPLICATIONS: ACTIVE CORRECTION OF OPTICAL ABERRATIONS FROM LOWER-GRADE OPTICS AND SUPPORT SYSTEM

    SciTech Connect

    Borra, E. F.

    2012-08-01

    Deformable mirrors are increasingly used in astronomy. However, they still are limited in stroke for active correction of high-amplitude optical aberrations. Magnetic liquid deformable mirrors (MLDMs) are a new technology that has the advantages of high-amplitude deformations and low costs. In this paper, we demonstrate extremely high strokes and interactuator strokes achievable by MLDMs which can be used in astronomical instrumentation. In particular, we consider the use of such a mirror to suggest an interesting application for the next generation of large telescopes. We present a prototype 91 actuator deformable mirror made of a magnetic liquid (ferrofluid). This mirror uses a technique that linearizes the response of such mirrors by superimposing a large and uniform magnetic field on the magnetic field produced by an array of small coils. We discuss experimental results that illustrate the performance of MLDMs. A most interesting application of MLDMs comes from the fact they could be used to correct the aberrations of large and lower optical quality primary mirrors held by simple support systems. We estimate basic parameters of the needed MLDMs, obtaining reasonable values.

  16. Differentiating Laryngeal Carcinomas from Precursor Lesions by Diffusion-Weighted Magnetic Resonance Imaging at 3.0 T: A Preliminary Study

    PubMed Central

    Shang, De-Sheng; Ruan, Ling-Xiang; Zhou, Shui-Hong; Bao, Yang-Yang; Cheng, Ke-Jia; Wang, Qin-Ying

    2013-01-01

    Background Diffusion-weighted magnetic resonance imaging (DWI) has been introduced in head and neck cancers. Due to limitations in the performance of laryngeal DWI, including the complex anatomical structure of the larynx leading to susceptibility effects, the value of DWI in differentiating benign from malignant laryngeal lesions has largely been ignored. We assessed whether a threshold for the apparent diffusion coefficient (ADC) was useful in differentiating preoperative laryngeal carcinomas from precursor lesions by turbo spin-echo (TSE) DWI and 3.0-T magnetic resonance. Methods We evaluated DWI and the ADC value in 33 pathologically proven laryngeal carcinomas and 17 precancerous lesions. Results The sensitivity, specificity, and accuracy were 81.8%, 64.7%, 76.0% by laryngostroboscopy, respectively. The sensitivity, specificity, and accuracy of conventional magnetic resonance imaging were 90.9%, 76.5%, 86.0%, respectively. Qualitative DWI analysis produced sensitivity, specificity, and accuracy values of 100.0, 88.2, and 96.0%, respectively. The ADC values were lower for patients with laryngeal carcinoma (mean 1.195±0.32×10−3 mm2/s) versus those with laryngeal precancerous lesions (mean 1.780±0.32×10−3 mm2/s; P<0.001). ROC analysis showed that the area under the curve was 0.956 and the optimum threshold for the ADC was 1.455×10−3 mm2/s, resulting in a sensitivity of 94.1%, a specificity of 90.9%, and an accuracy of 92.9%. Conclusions Despite some limitations, including the small number of laryngeal carcinomas included, DWI may detect changes in tumor size and shape before they are visible by laryngostroboscopy. The ADC values were lower for patients with laryngeal carcinoma than for those with laryngeal precancerous lesions. The proposed cutoff for the ADC may help distinguish laryngeal carcinomas from laryngeal precancerous lesions. PMID:23874693

  17. Study on immobilization of yeast alcohol dehydrogenase on nanocrystalline Ni-Co ferrites as magnetic support.

    PubMed

    Shakir, Mohammad; Nasir, Zeba; Khan, Mohd Shoeb; Lutfullah; Alam, Md Fazle; Younus, Hina; Al-Resayes, Saud Ibrahim

    2015-01-01

    The covalent binding of yeast alcohol dehydrogenase (YADH) enzyme complex in a series of magnetic crystalline Ni-Co nanoferrites, synthesized via sol-gel auto combustion technique was investigated. The structural analysis, morphology and magnetic properties of Ni-Co nanoferrites were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), vibrating-sample magnetometer (VSM), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The comparative analysis of the HRTEM micrographs of bare magnetic nanoferrite particles and particles immobilized with enzyme revealed an uniform distribution of the particles in both the cases without undergoing change in the size which was found to be in the range 20-30 nm. The binding of YADH to Ni-Co nanoferrites and the possible binding mechanism have been suggested by comparing the FTIR results. The binding properties of the immobilized YADH enzyme were also studied by kinetic parameters, optimum operational pH, temperature, thermal stability and reusability. The immobilized YADH exhibits enhanced thermal stability as compared to the free enzyme over a wide range of temperature and pH, and showed good durability after recovery by magnetic separation for repeated use. PMID:25450541

  18. Optimal b value of diffusion-weighted imaging on a 3.0T magnetic resonance scanner in Crohn’s disease

    PubMed Central

    Feng, Qi; Yan, Yun-Qi; Zhu, Jiong; Tong, Jin-Lu; Xu, Jian-Rong

    2014-01-01

    AIM: To determine the optimal b value of diffusion-weighted imaging for detecting active inflammation in Crohn’s disease. METHODS: Thirty-one patients clinically diagnosed with active Crohn’s disease were referred for magnetic resonance examination. All patients were scanned on a 3.0T magnetic resonance scanner using the same protocol involving four different b values (800, 1500, 2000 and 2500 s/mm2). The diagnostic effect of diffusion-weighted imaging was evaluated and compared with endoscopic findings. The diffusion-weighted image quality of four b value groups was evaluated and apparent diffusion coefficient was measured for both normal and inflammatory intestinal segments. RESULTS: The contrast-to-noise ratio and signal-to-noise ratio were not satisfied when b value 2000 or 2500 s/mm2 was adopted (36.52 ± 14.95 vs 34.78 ± 24.83, P > 0.05; 53.58 ± 23.45 vs 47.58 ± 29.67, P > 0.05). The qualitative image quality was not enough to meet diagnostic requirement. No matter which b value was chosen, the apparent diffusion coefficient of inflammatory intestinal segments was significantly lower than that of normal intestinal segments (1.38 ± 0.28 vs 2.00 ± 0.38, P < 0.01; 1.09 ± 0.20 vs 1.50 ± 0.28, P < 0.01; 0.95 ± 0.19 vs 1.34 ± 0.28, P < 0.01; 0.88 ± 0.14 vs 1.20 ± 0.21, P < 0.01). The lesion detection rate (90.32%), diagnostic sensitivity (81.18%) and specificity (95.10%) would be appropriate when b value 1500 s/mm2 was adopted. CONCLUSION: High b value is suitable for intestinal DW examination on a high field MR scanner. PMID:25253967

  19. 2D segmentation of intervertebral discs and its degree of degeneration from T2-weighted magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Castro-Mateos, Isaac; Pozo, José Maria; Lazary, Aron; Frangi, Alejandro F.

    2014-03-01

    Low back pain (LBP) is a disorder suffered by a large population around the world. A key factor causing this illness is Intervertebral Disc (IVD) degeneration, whose early diagnosis could help in preventing this widespread condition. Clinicians base their diagnosis on visual inspection of 2D slices of Magnetic Resonance (MR) images, which is subject to large interobserver variability. In this work, an automatic classification method is presented, which provides the Pfirrmann degree of degeneration from a mid-sagittal MR slice. The proposed method utilizes Active Contour Models, with a new geometrical energy, to achieve an initial segmentation, which is further improved using fuzzy C-means. Then, IVDs are classified according to their degree of degeneration. This classification is attained by employing Adaboost on five specific features: the mean and the variance of the probability map of the nucleus using two different approaches and the eccentricity of the fitting ellipse to the contour of the IVD. The classification method was evaluated using a cohort of 150 intervertebral discs assessed by three experts, resulting in a mean specificity (93%) and sensitivity (83%) similar to the one provided by every expert with respect to the most voted value. The segmentation accuracy was evaluated using the Dice Similarity Index (DSI) and Root Mean Square Error (RMSE) of the point-to-contour distance. The mean DSI ± 2 standard deviation was 91:7% ±5:6%, the mean RMSE was 0:82mm and the 95 percentile was 1:36mm. These results were found accurate when compared to the state-of-the-art.

  20. Cobalt salophen complex supported on imidazole functionalized magnetic nanoparticles as a recoverable catalyst for oxidation of alkenes

    NASA Astrophysics Data System (ADS)

    Afshari, Mozhgan; Gorjizadeh, Maryam; Nazari, Simin; Naseh, Mohammad

    2014-08-01

    A new magnetically separable catalyst consisting of Co(II) salophen complex covalently supported on imidazole functionalized silica coated cobalt ferrite was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Fourier transform infrared (FT-IR). The immobilized catalyst was shown to be an efficient heterogeneous catalyst for the oxidation of some alkenes using hydrogen peroxide (H2O2) as oxidant. The catalyst could be easily and efficiently isolated from the final product solution by magnetic decantation and be reused for 5 consecutive reactions without showing any significant activity degradation.

  1. Role of Diffusion-Weighted Magnetic Resonance Imaging in Predicting Sensitivity to Chemoradiotherapy in Muscle-Invasive Bladder Cancer

    SciTech Connect

    Yoshida, Soichiro; Koga, Fumitaka; Kobayashi, Shuichiro; Ishii, Chikako; Tanaka, Hiroshi; Tanaka, Hajime; Komai, Yoshinobu; Saito, Kazutaka; Masuda, Hitoshi; Fujii, Yasuhisa; Kawakami, Satoru; Kihara, Kazunori

    2012-05-01

    Purpose: In chemoradiation (CRT)-based bladder-sparing approaches for muscle invasive bladder cancer (MIBC), patients who respond favorably to induction CRT enjoy the benefits of bladder preservation, whereas nonresponders do not. Thus, accurate prediction of CRT sensitivity would optimize patient selection for bladder-sparing protocols. Diffusion-weighted MRI (DW-MRI) is a functional imaging technique that quantifies the diffusion of water molecules in a noninvasive manner. We investigated whether DW-MRI predicts CRT sensitivity of MIBC. Methods and Materials: The study cohort consisted of 23 MIBC patients (cT2/T3 = 7/16) who underwent induction CRT consisting of radiotherapy to the small pelvis (40 Gy) with two cycles of cisplatin (20 mg/day for 5 days), followed by partial or radical cystectomy. All patients underwent DW-MRI before the initiation of treatment. Associations of apparent diffusion coefficient (ADC) values with CRT sensitivity were analyzed. The proliferative potential of MIBC was also assessed by analyzing the Ki-67 labeling index (LI) in pretherapeutic biopsy specimens. Results: Thirteen patients (57%) achieved pathologic complete response (pCR) to CRT. These CRT-sensitive MIBCs showed significantly lower ADC values (median, 0.63 Multiplication-Sign 10{sup -3} mm{sup 2}/s; range, 0.43-0.77) than CRT-resistant (no pCR) MIBCs (median, 0.84 Multiplication-Sign 10{sup -3} mm{sup 2}/s; range, 0.69-1.09; p = 0.0003). Multivariate analysis identified ADC value as the only significant and independent predictor of CRT sensitivity (p < 0.0001; odds ratio per 0.001 Multiplication-Sign 10{sup -3} mm{sup 2}/s increase, 1.03; 95% confidence interval, 1.01-1.08). With a cutoff ADC value at 0.74 Multiplication-Sign 10{sup -3} mm{sup 2}/s, sensitivity/specificity/accuracy in predicting CRT sensitivity was 92/90/91%. Ki-67 LI was significantly higher in CRT-sensitive MIBCs (p = 0.0005) and significantly and inversely correlated with ADC values ({rho} = -0.67, p = 0

  2. Altered hepatic gluconeogenesis during L-alanine infusion in weight-losing lung cancer patients as observed by phosphorus magnetic resonance spectroscopy and turnover measurements.

    PubMed

    Leij-Halfwerk, S; van den Berg, J W; Sijens, P E; Wilson, J H; Oudkerk, M; Dagnelie, P C

    2000-02-01

    Profound alterations in host metabolism in lung cancer patients with weight loss have been reported, including elevated phosphomonoesters (PMEs) as detected by 31P magnetic resonance spectroscopy (MRS). In healthy subjects, infusion of L-alanine induced significant increases in hepatic PMEs and phosphodiesters (PDEs) due to rising concentrations of 3-phosphoglycerate and phosphoenolpyruvate, respectively. The aim of the present study was to monitor these changes in the tumor-free liver of lung cancer patients during L-alanine infusion by means of simultaneous 31P MRS and turnover measurements. Twenty-one lung cancer patients without liver metastases with (CaWL) or without weight loss (CaWS), and 12 healthy control subjects were studied during an i.v. L-alanine challenge of 1.4-2.8 mmol/kg followed by 2.8 mmol/kg/h for 90 min. Plasma L-alanine concentrations increased during alanine infusion, from 0.35-0.37 mM at baseline to 5.37 +/- 0.14 mM in the CaWL patients, 6.67 +/- 0.51 mM in the CaWS patients, and 8.47 +/- 0.88 mM in the controls (difference from baseline and between groups during alanine infusion, all P < 0.001). Glucose turnover and liver PME levels at baseline were significantly elevated in the CaWL patients. Alanine infusion increased whole-body glucose turnover by 8 +/- 3% in the CaWS patients (P = 0.03), whereas no significant change occurred in the CaWL and controls. PME levels increased by 50 +/- 16% in controls (area under the curve, P < 0.01) and by 87 +/- 31% in the CaWS patients (P < 0.05) after 45-90 min. In contrast, no significant changes in PME levels were observed in the CaWL patients. Plasma insulin concentrations increased during L-alanine infusion in all groups to levels that were lower in the CaWL patients than in the CaWS patients and controls (P < 0.05). In lung cancer patients, but not in controls, changes in PME and PDE levels during alanine infusion were inversely correlated with their respective baseline levels (r = -0.82 and -0

  3. A Combination of Geographically Weighted Regression, Particle Swarm Optimization and Support Vector Machine for Landslide Susceptibility Mapping: A Case Study at Wanzhou in the Three Gorges Area, China

    PubMed Central

    Yu, Xianyu; Wang, Yi; Niu, Ruiqing; Hu, Youjian

    2016-01-01

    In this study, a novel coupling model for landslide susceptibility mapping is presented. In practice, environmental factors may have different impacts at a local scale in study areas. To provide better predictions, a geographically weighted regression (GWR) technique is firstly used in our method to segment study areas into a series of prediction regions with appropriate sizes. Meanwhile, a support vector machine (SVM) classifier is exploited in each prediction region for landslide susceptibility mapping. To further improve the prediction performance, the particle swarm optimization (PSO) algorithm is used in the prediction regions to obtain optimal parameters for the SVM classifier. To evaluate the prediction performance of our model, several SVM-based prediction models are utilized for comparison on a study area of the Wanzhou district in the Three Gorges Reservoir. Experimental results, based on three objective quantitative measures and visual qualitative evaluation, indicate that our model can achieve better prediction accuracies and is more effective for landslide susceptibility mapping. For instance, our model can achieve an overall prediction accuracy of 91.10%, which is 7.8%–19.1% higher than the traditional SVM-based models. In addition, the obtained landslide susceptibility map by our model can demonstrate an intensive correlation between the classified very high-susceptibility zone and the previously investigated landslides. PMID:27187430

  4. A Combination of Geographically Weighted Regression, Particle Swarm Optimization and Support Vector Machine for Landslide Susceptibility Mapping: A Case Study at Wanzhou in the Three Gorges Area, China.

    PubMed

    Yu, Xianyu; Wang, Yi; Niu, Ruiqing; Hu, Youjian

    2016-01-01

    In this study, a novel coupling model for landslide susceptibility mapping is presented. In practice, environmental factors may have different impacts at a local scale in study areas. To provide better predictions, a geographically weighted regression (GWR) technique is firstly used in our method to segment study areas into a series of prediction regions with appropriate sizes. Meanwhile, a support vector machine (SVM) classifier is exploited in each prediction region for landslide susceptibility mapping. To further improve the prediction performance, the particle swarm optimization (PSO) algorithm is used in the prediction regions to obtain optimal parameters for the SVM classifier. To evaluate the prediction performance of our model, several SVM-based prediction models are utilized for comparison on a study area of the Wanzhou district in the Three Gorges Reservoir. Experimental results, based on three objective quantitative measures and visual qualitative evaluation, indicate that our model can achieve better prediction accuracies and is more effective for landslide susceptibility mapping. For instance, our model can achieve an overall prediction accuracy of 91.10%, which is 7.8%-19.1% higher than the traditional SVM-based models. In addition, the obtained landslide susceptibility map by our model can demonstrate an intensive correlation between the classified very high-susceptibility zone and the previously investigated landslides. PMID:27187430

  5. Methods for a Randomized Trial of Weight-Supported Treadmill Training versus Conventional Training for Walking during Inpatient Rehabilitation after Incomplete Traumatic Spinal Cord Injury

    PubMed Central

    Dobkin, Bruce H.; Apple, David; Barbeau, Hugues; Basso, Michele; Behrman, Andrea; Deforge, Dan; Ditunno, John; Dudley, Gary; Elashoff, Robert; Fugate, Lisa; Harkema, Susan; Saulino, Michael; Scott, Michael

    2014-01-01

    The authors describe the rationale and methodology for the first prospective, multicenter, randomized clinical trial (RCT) of a task-oriented walking intervention for subjects during early rehabilitation for an acute traumatic spinal cord injury (SCI). The experimental strategy, body weight–supported treadmill training (BWSTT), allows physical therapists to systematically train patients to walk on a treadmill at increasing speeds typical of community ambulation with increasing weight bearing. The therapists provide verbal and tactile cues to facilitate the kinematic, kinetic, and temporal features of walking. Subjects were randomly assigned to a conventional therapy program for mobility versus the same intensity and duration of a combination of BWSTT and over-ground locomotor retraining. Subjects had an incomplete SCI (American Spinal Injury Association grades B, C, and D) from C-4 to T-10 (upper motoneuron group) or from T-11 to L-3 (lower motoneuron group). Within 8 weeks of a SCI, 146 subjects were entered for 12 weeks of intervention. The 2 single-blinded primary outcome measures are the level of independence for ambulation and, for those who are able to walk, the maximal speed for walking 50 feet, tested 6 and 12 months after randomization. The trial’s methodology offers a model for the feasibility of translating neuroscientific experiments into a RCT to develop evidence-based rehabilitation practices. PMID:14503436

  6. Polystyrene or Magnetic Nanoparticles as Support in Enantioselective Organocatalysis? A Case Study in Friedel-Crafts Chemistry.

    PubMed

    Ranjbar, Sara; Riente, Paola; Rodríguez-Escrich, Carles; Yadav, Jagjit; Ramineni, Kishore; Pericàs, Miquel A

    2016-04-01

    Heterogenized versions of the second-generation MacMillan imidazolidin-4-one are described for the first time. This versatile organocatalyst has been supported on 1% DVB Merrifield resin and Fe3O4 magnetic nanoparticles through a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. The resulting catalytic materials have been successfully applied to the asymmetric Friedel-Crafts alkylation of indoles with α,β-unsaturated aldehydes. While both catalytic systems can be easily recovered and admit repeated recycling, the polystyrene-based catalyst shows higher stability and provides better stereoselectivities. PMID:27010999

  7. Alternate design concept for the SSC dipole magnet cryogenic support post

    SciTech Connect

    Lipski, A.; Nicol, T.H.; Richardson, R.

    1991-03-01

    New materials and developments in the field of advanced composites have created the opportunity to take a fresh look into the design of the cryogenic supports for SSC collider dipole cryostats. Although the present reentrant post design meets the structural and thermal requirements, its assembly requires precision and proficiency. The objective of the proposed alternate concept is to reduce the overall cost of the support post by means of simplifying and optimizing its component design and assembly process. The present shrink fitted tube assembly may potentially be replaced by injection molded parts. New resin systems with lower thermal conductivity and high strength properties enable the utilization of automated production techniques such as injection molding and filament winding. This paper will provide analysis and design information for the alternate support post concept and compare its test performance and cost to the present support post. 3 refs., 12 figs., 4 tabs.

  8. Dynamic behavior of a magnetic bearing supported jet engine rotor with auxiliary bearings

    NASA Technical Reports Server (NTRS)

    Flowers, George T.; Xie, Huajun; Sinha, S. C.

    1995-01-01

    This paper presents a study of the dynamic behavior of a rotor system supported by auxiliary bearings. The steady-state behavior of a simulation model based upon a production jet engine is explored over a wide range of operating conditions for varying rotor imbalance, support stiffness, and damping. Interesting dynamical phenomena, such as chaos, subharmonic responses, and double-valued responses, are presented and discussed.

  9. Dynamic behavior of a magnetic bearing supported jet engine rotor with auxiliary bearings

    NASA Technical Reports Server (NTRS)

    Homaifar, Abdollah (Editor); Kelly, John C., Jr. (Editor); Flowers, G. T.; Xie, H.; Sinha, S. C.

    1994-01-01

    This paper presents a study of the dynamic behavior of a rotor system supported by auxiliary bearings. The steady-state behavior of a simulation model based upon a production jet engine is explored over a wide range of operating conditions for varying rotor imbalance, support stiffness and damping. Interesting dynamical phenomena, such as chaos, subharmonic responses, and double-valued responses, are presented and discussed.

  10. Weighted aggregation

    NASA Technical Reports Server (NTRS)

    Feiveson, A. H. (Principal Investigator)

    1979-01-01

    The use of a weighted aggregation technique to improve the precision of the overall LACIE estimate is considered. The manner in which a weighted aggregation technique is implemented given a set of weights is described. The problem of variance estimation is discussed and the question of how to obtain the weights in an operational environment is addressed.

  11. Demonstration of Non-Gaussian Restricted Diffusion in Tumor Cells Using Diffusion Time-Dependent Diffusion-Weighted Magnetic Resonance Imaging Contrast.

    PubMed

    Hope, Tuva R; White, Nathan S; Kuperman, Joshua; Chao, Ying; Yamin, Ghiam; Bartch, Hauke; Schenker-Ahmed, Natalie M; Rakow-Penner, Rebecca; Bussell, Robert; Nomura, Natsuko; Kesari, Santosh; Bjørnerud, Atle; Dale, Anders M

    2016-01-01

    The diffusion-weighted magnetic resonance imaging (DWI) technique enables quantification of water mobility for probing microstructural properties of biological tissue and has become an effective tool for collecting information about the underlying pathology of cancerous tissue. Measurements using multiple b-values have indicated biexponential signal attenuation, ascribed to "fast" (high ADC) and "slow" (low ADC) diffusion components. In this empirical study, we investigate the properties of the diffusion time (Δ)-dependent components of the diffusion-weighted (DW) signal in a constant b-value experiment. A xenograft gliobastoma mouse was imaged using Δ = 11 ms, 20 ms, 40 ms, 60 ms, and b = 500-4000 s/mm(2) in intervals of 500 s/mm(2). Data were corrected for EPI distortions, and the Δ-dependence on the DW-signal was measured within three regions of interest [intermediate- and high-density tumor regions and normal-appearing brain (NAB) tissue regions]. In this study, we verify the assumption that the slow decaying component of the DW-signal is non-Gaussian and dependent on Δ, consistent with restricted diffusion of the intracellular space. As the DW-signal is a function of Δ and is specific to restricted diffusion, manipulating Δ at constant b-value (cb) provides a complementary and direct approach for separating the restricted from the hindered diffusion component. We found that Δ-dependence is specific to the tumor tissue signal. Based on an extended biexponential model, we verified the interpretation of the diffusion time-dependent contrast and successfully estimated the intracellular restricted ADC, signal volume fraction, and cell size within each ROI. PMID:27532028

  12. Demonstration of Non-Gaussian Restricted Diffusion in Tumor Cells Using Diffusion Time-Dependent Diffusion-Weighted Magnetic Resonance Imaging Contrast

    PubMed Central

    Hope, Tuva R.; White, Nathan S.; Kuperman, Joshua; Chao, Ying; Yamin, Ghiam; Bartch, Hauke; Schenker-Ahmed, Natalie M.; Rakow-Penner, Rebecca; Bussell, Robert; Nomura, Natsuko; Kesari, Santosh; Bjørnerud, Atle; Dale, Anders M.

    2016-01-01

    The diffusion-weighted magnetic resonance imaging (DWI) technique enables quantification of water mobility for probing microstructural properties of biological tissue and has become an effective tool for collecting information about the underlying pathology of cancerous tissue. Measurements using multiple b-values have indicated biexponential signal attenuation, ascribed to “fast” (high ADC) and “slow” (low ADC) diffusion components. In this empirical study, we investigate the properties of the diffusion time (Δ)-dependent components of the diffusion-weighted (DW) signal in a constant b-value experiment. A xenograft gliobastoma mouse was imaged using Δ = 11 ms, 20 ms, 40 ms, 60 ms, and b = 500–4000 s/mm2 in intervals of 500 s/mm2. Data were corrected for EPI distortions, and the Δ-dependence on the DW-signal was measured within three regions of interest [intermediate- and high-density tumor regions and normal-appearing brain (NAB) tissue regions]. In this study, we verify the assumption that the slow decaying component of the DW-signal is non-Gaussian and dependent on Δ, consistent with restricted diffusion of the intracellular space. As the DW-signal is a function of Δ and is specific to restricted diffusion, manipulating Δ at constant b-value (cb) provides a complementary and direct approach for separating the restricted from the hindered diffusion component. We found that Δ-dependence is specific to the tumor tissue signal. Based on an extended biexponential model, we verified the interpretation of the diffusion time-dependent contrast and successfully estimated the intracellular restricted ADC, signal volume fraction, and cell size within each ROI. PMID:27532028

  13. Evaluating Mesorectal Lymph Nodes in Rectal Cancer Before and After Neoadjuvant Chemoradiation Using Thin-Section T2-Weighted Magnetic Resonance Imaging

    SciTech Connect

    Koh, Dow-Mu Chau, Ian; Tait, Diana; Wotherspoon, Andrew; Cunningham, David; Brown, Gina

    2008-06-01

    Purpose: To apply thin-section T2-weighted magnetic resoance imaging (MRI) to evaluate the number, size, distribution, and morphology of benign and malignant mesorectal lymph nodes before and after chemoradiation treatment compared with histopathologic findings. Methods and Materials: Twenty-five patients with poor-risk adenocarcinoma of the rectum treated with neoadjuvant chemoradiation were evaluated prospectively. Thin-section T2-weighted MR images obtained before and after chemoradiation treatment were independently reviewed in consensus by 2 expert radiologists to determine the tumor stage, nodal size, nodal distribution, and nodal stage. Total mesorectal excision surgery after chemoradiation allowed MR nodal stage to be compared with histopathology using {kappa} statistics. Nodal downstaging was compared using the Chi-square test. Results: Before chemoradiation, 152 mesorectal nodes were visible (mean, 6.2 mm; 100 benign, 52 malignant) and 4 of 52 malignant nodes were in contact with the mesorectal fascia. The nodal staging was 7/25 N0, 10/25 N1, and 7/25 N2. After chemoradiation, only 29 nodes (mean, 4.1 mm; 24 benign, 5 malignant) were visible, and none were in contact with the mesorectal fascia. Nodal downstaging was observed: 20/25 N0 and 5/25 N1 (p < 0.01, Chi-square test). There was good agreement between MRI and pathologic T-staging ({kappa} = 0.64) and N-staging ({kappa} = 0.65) after chemoradiation. Conclusions: Neoadjuvant chemoradiation treatment resulted in a decrease in size and number of malignant- and benign-appearing mesorectal nodes on MRI. Nodal downstaging and nodal regression from the mesorectal fascia were observed after treatment. MRI is a useful tool for assessing nodal response to neoadjuvant treatment.

  14. Cerebral edema induced in mice by a convulsive dose of soman. Evaluation through diffusion-weighted magnetic resonance imaging and histology

    SciTech Connect

    Testylier, Guy . E-mail: guytestylier@crssa.net; Lahrech, Hana; Montigon, Olivier; Foquin, Annie; Delacour, Claire; Bernabe, Denis; Segebarth, Christoph; Dorandeu, Frederic; Carpentier, Pierre

    2007-04-15

    Purpose: In the present study, diffusion-weighted magnetic resonance imaging (DW-MRI) and histology were used to assess cerebral edema and lesions in mice intoxicated by a convulsive dose of soman, an organophosphate compound acting as an irreversible cholinesterase inhibitor. Methods: Three hours and 24 h after the intoxication with soman (172 {mu}g/kg), the mice were anesthetized with an isoflurane/N{sub 2}O mixture and their brain examined with DW-MRI. After the imaging sessions, the mice were sacrificed for histological analysis of their brain. Results: A decrease in the apparent diffusion coefficient (ADC) was detected as soon as 3 h after the intoxication and was found strongly enhanced at 24 h. A correlation was obtained between the ADC change and the severity of the overall brain damage (edema and cellular degeneration): the more severe the damage, the stronger the ADC drop. Anesthesia was shown to interrupt soman-induced seizures and to attenuate edema and cell change in certain sensitive brain areas. Finally, brain water content was assessed using the traditional dry/wet weight method. A significant increase of brain water was observed following the intoxication. Conclusions: The ADC decrease observed in the present study suggests that brain edema in soman poisoning is mainly intracellular and cytotoxic. Since entry of water into Brain was also evidenced, this type of edema is certainly mixed with others (vasogenic, hydrostatic, osmotic). The present study confirms the potential of DW-MRI as a non-invasive tool for monitoring the acute neuropathological consequences (edema and neurodegeneration) of soman-induced seizures.

  15. Comparison of [{sup 11}C]choline Positron Emission Tomography With T2- and Diffusion-Weighted Magnetic Resonance Imaging for Delineating Malignant Intraprostatic Lesions

    SciTech Connect

    Chang, Joe H.; Lim Joon, Daryl; Davis, Ian D.; Lee, Sze Ting; Hiew, Chee-Yan; Esler, Stephen; Gong, Sylvia J.; Wada, Morikatsu; Clouston, David; O'Sullivan, Richard; Goh, Yin P.; Bolton, Damien; Scott, Andrew M.; Khoo, Vincent

    2015-06-01

    Purpose: The purpose of this study was to compare the accuracy of [{sup 11}C]choline positron emission tomography (CHOL-PET) with that of the combination of T2-weighted and diffusion-weighted (T2W/DW) magnetic resonance imaging (MRI) for delineating malignant intraprostatic lesions (IPLs) for guiding focal therapies and to investigate factors predicting the accuracy of CHOL-PET. Methods and Materials: This study included 21 patients who underwent CHOL-PET and T2W/DW MRI prior to radical prostatectomy. Two observers manually delineated IPL contours for each scan, and automatic IPL contours were generated on CHOL-PET based on varying proportions of the maximum standardized uptake value (SUV). IPLs identified on prostatectomy specimens defined reference standard contours. The imaging-based contours were compared with the reference standard contours using Dice similarity coefficient (DSC), and sensitivity and specificity values. Factors that could potentially predict the DSC of the best contouring method were analyzed using linear models. Results: The best automatic contouring method, 60% of the maximum SUV (SUV{sub 60}) , had similar correlations (DSC: 0.59) with the manual PET contours (DSC: 0.52, P=.127) and significantly better correlations than the manual MRI contours (DSC: 0.37, P<.001). The sensitivity and specificity values were 72% and 71% for SUV{sub 60}; 53% and 86% for PET manual contouring; and 28% and 92% for MRI manual contouring. The tumor volume and transition zone pattern could independently predict the accuracy of CHOL-PET. Conclusions: CHOL-PET is superior to the combination of T2W/DW MRI for delineating IPLs. The accuracy of CHOL-PET is insufficient for gland-sparing focal therapies but may be accurate enough for focal boost therapies. The transition zone pattern is a new classification that may predict how well CHOL-PET delineates IPLs.

  16. Comparison of dynamic contrast-enhanced and diffusion weighted magnetic resonance image in staging and grading of carcinoma bladder with histopathological correlation

    PubMed Central

    Gupta, Neetika; Sureka, Binit; Kumar, Mittal Mahesh; Malik, Amita; Bhushan, Thukral Brij; Mohanty, N. K.

    2015-01-01

    Background: Bladder cancer is the second most common neoplasm of the urinary tract worldwide. Dynamic contrast-enhanced and diffusion-weighted MRI has been introduced in clinical MRI protocols of bladder cancer because of its accuracy in staging and grading. Aim: To evaluate and compare accuracy of Dynamic contrast enhanced (DCE) and Diffusion weighted (DW) MRI for preoperative T staging of urinary bladder cancer and find correlation between apparent diffusion coefficient (ADC) and maximum enhancement with histological grade. Materials and Methods: Sixty patients with bladder cancer were included in study. All patients underwent Magnetic Resonance Imaging (MRI) on a 1.5-T scanner with a phased-array pelvic coil. MR images were evaluated and assigned a stage which was compared with the histolopathological staging. ADC value and maximum enhancement curve were used based on previous studies. Subsequently histological grade was compared with MR characteristics. Results: The extent of agreement between the radiologic staging and histopathological staging was relatively greater with the DW-MRI (κ=0.669) than DCE-MRI (κ=0.619). The sensitivity, specificity, and accuracy are maximum and similar for stage T4 tumors in both DCEMRI (100.0, 96.2 and 96.7) and DW-MRI (100.0, 96.2 and 96.7) while minimum for stage T2 tumors - DCEMRI (83.3, 72.2, and 76.7) and DWI-MRI (91.7, 72.2, and 80). Conclusion: MRI is an effective tool for determining T stage and histological grade of urinary bladder cancers. Stage T2a and T2b can be differentiated only by DCE-MRI. Results were more accurate when both ADC and DCE-MRI were used together and hence a combined approach is suggested. PMID:25835087

  17. Characteristics of liver on magnetic resonance diffusion-weighted imaging: Dynamic and image pathological investigation in rabbit liver VX-2 tumor model

    PubMed Central

    Yuan, You-Hong; Xiao, En-Hua; Liu, Jian-Bin; He, Zhong; Jin, Ke; Ma, Cong; Xiang, Jun; Xiao, Jian-Hua; Chen, Wei-Jian

    2008-01-01

    AIM: To investigate dynamical and image pathological characteristics of the liver on magnetic resonance (MR) diffusion-weighted imaging (DWI) in the rabbit VX-2 tumor model. METHODS: Forty New Zealand rabbits were included in the study and VX-2 tumor piece was implanted intrahepatically. Fifteen animals received two intrahepatic implantations while 25 had one intrahepatical implantation. DWI, T1- and T2-weighted of magnetic resonance imaging (MRI) were carried out on the 7th and the 14th d after implantation and DWI was conducted, respectively on the 21th d. Ten VX-2 tumor samples were studied pathologically. RESULTS: The rate of lump detected by DWI, T1WI and T2WI was 78.7%, 10.7% and 53.5% (χ2 = 32.61, P < 0.001) on the 7th d after implantation and 95.8%, 54.3% and 82.9% (χ2 = 21.50, P < 0.001) on the 14th d. The signal of most VX-2 tumors on DWI was uniform and it was equal on the map of apparent diffusion coefficient (ADC). The signal of VX tumors did not decrease on the 7th d after implantation, most of them slowly growing during the week following implantation without significant cell dying within the tumor. VX-2 tumors grew increasingly within 14 d after implantation but the signal of most VX-2 tumors on DWI or on the map of ADC was uniform or uneven and ADC of VX tumors decreased obscurely or slightly because tumor necrosis was still not obvious. On the 21th d after implantation, the signal of most VX-2 tumors on DWI or on the map of ADC was uneven because tumor necrosis was evident and ADC of VX-2 tumor necrotic areas decreased. The areas of viable cells in VX-2 tumors manifested a high signal on DWI and a low signal on the map of ADC. The areas of dead cells or necrosis in VX-2 tumors manifested low signals on DWI and low, equal or high signals on the map of ADC but they manifested high signals on DWI and on the map of ADC at the same time when the areas of necrotic tumor became liquefied or cystic. The border of tumors on DWI appeared gradually

  18. Prostate Postbrachytherapy Seed Distribution: Comparison of High-Resolution, Contrast-Enhanced, T1- and T2-Weighted Endorectal Magnetic Resonance Imaging Versus Computed Tomography: Initial Experience

    SciTech Connect

    Bloch, B. Nicolas Lenkinski, Robert E.; Helbich, Thomas H.; Ngo, Long; Oismueller, Renee; Jaromi, Silvia; Kubin, Klaus; Hawliczek, Robert; Kaplan, Irving D.; Rofsky, Neil M.

    2007-09-01

    Purpose: To compare contrast-enhanced, T1-weighted, three-dimensional magnetic resonance imaging (CEMR) and T2-weighted magnetic resonance imaging (T2MR) with computed tomography (CT) for prostate brachytherapy seed location for dosimetric calculations. Methods and Materials: Postbrachytherapy prostate MRI was performed on a 1.5 Tesla unit with combined surface and endorectal coils in 13 patients. Both CEMR and T2MR used a section thickness of 3 mm. Spiral CT used a section thickness of 5 mm with a pitch factor of 1.5. All images were obtained in the transverse plane. Two readers using CT and MR imaging assessed brachytherapy seed distribution independently. The dependency of data read by both readers for a specific subject was assessed with a linear mixed effects model. Results: The mean percentage ({+-} standard deviation) values of the readers for seed detection and location are presented. Of 1205 implanted seeds, CEMR, T2MR, and CT detected 91.5% {+-} 4.8%, 78.5% {+-} 8.5%, and 96.1% {+-} 2.3%, respectively, with 11.8% {+-} 4.5%, 8.5% {+-} 3.5%, 1.9% {+-} 1.0% extracapsular, respectively. Assignment to periprostatic structures was not possible with CT. Periprostatic seed assignments for CEMR and T2MR, respectively, were as follows: neurovascular bundle, 3.5% {+-} 1.6% and 2.1% {+-} 0.9%; seminal vesicles, 0.9% {+-} 1.8% and 0.3% {+-} 0.7%; periurethral, 7.1% {+-} 3.3% and 5.8% {+-} 2.9%; penile bulb, 0.6% {+-} 0.8% and 0.3% {+-} 0.6%; Denonvillier's Fascia/rectal wall, 0.5% {+-} 0.6% and 0%; and urinary bladder, 0.1% {+-} 0.3% and 0%. Data dependency analysis showed statistical significance for the type of imaging but not for reader identification. Conclusion: Both enumeration and localization of implanted seeds are readily accomplished with CEMR. Calculations with MRI dosimetry do not require CT data. Dose determinations to specific extracapsular sites can be obtained with MRI but not with CT.

  19. Bayesian integrated testing strategy (ITS) for skin sensitization potency assessment: a decision support system for quantitative weight of evidence and adaptive testing strategy.

    PubMed

    Jaworska, Joanna S; Natsch, Andreas; Ryan, Cindy; Strickland, Judy; Ashikaga, Takao; Miyazawa, Masaaki

    2015-12-01

    The presented Bayesian network Integrated Testing Strategy (ITS-3) for skin sensitization potency assessment is a decision support system for a risk assessor that provides quantitative weight of evidence, leading to a mechanistically interpretable potency hypothesis, and formulates adaptive testing strategy for a chemical. The system was constructed with an aim to improve precision and accuracy for predicting LLNA potency beyond ITS-2 (Jaworska et al., J Appl Toxicol 33(11):1353-1364, 2013) by improving representation of chemistry and biology. Among novel elements are corrections for bioavailability both in vivo and in vitro as well as consideration of the individual assays' applicability domains in the prediction process. In ITS-3 structure, three validated alternative assays, DPRA, KeratinoSens and h-CLAT, represent first three key events of the adverse outcome pathway for skin sensitization. The skin sensitization potency prediction is provided as a probability distribution over four potency classes. The probability distribution is converted to Bayes factors to: 1) remove prediction bias introduced by the training set potency distribution and 2) express uncertainty in a quantitative manner, allowing transparent and consistent criteria to accept a prediction. The novel ITS-3 database includes 207 chemicals with a full set of in vivo and in vitro data. The accuracy for predicting LLNA outcomes on the external test set (n = 60) was as follows: hazard (two classes)-100 %, GHS potency classification (three classes)-96 %, potency (four classes)-89 %. This work demonstrates that skin sensitization potency prediction based on data from three key events, and often less, is possible, reliable over broad chemical classes and ready for practical applications. PMID:26612363

  20. The Effect of Body Weight Support Treadmill Training on Gait Recovery, Proximal Lower Limb Motor Pattern, and Balance in Patients with Subacute Stroke

    PubMed Central

    Mao, Yu-Rong; Lo, Wai Leung; Lin, Qiang; Li, Le; Xiao, Xiang; Raghavan, Preeti; Huang, Dong-Feng

    2015-01-01

    Objective. Gait performance is an indicator of mobility impairment after stroke. This study evaluated changes in balance, lower extremity motor function, and spatiotemporal gait parameters after receiving body weight supported treadmill training (BWSTT) and conventional overground walking training (CT) in patients with subacute stroke using 3D motion analysis. Setting. Inpatient department of rehabilitation medicine at a university-affiliated hospital. Participants. 24 subjects with unilateral hemiplegia in the subacute stage were randomized to the BWSTT (n = 12) and CT (n = 12) groups. Parameters were compared between the two groups. Data from twelve age matched healthy subjects were recorded as reference. Interventions. Patients received gait training with BWSTT or CT for an average of 30 minutes/day, 5 days/week, for 3 weeks. Main Outcome Measures. Balance was measured by the Brunel balance assessment. Lower extremity motor function was evaluated by the Fugl-Meyer assessment scale. Kinematic data were collected and analyzed using a gait capture system before and after the interventions. Results. Both groups improved on balance and lower extremity motor function measures (P < 0.05), with no significant difference between the two groups after intervention. However, kinematic data were significantly improved (P < 0.05) after BWSTT but not after CT. Maximum hip extension and flexion angles were significantly improved (P < 0.05) for the BWSTT group during the stance and swing phases compared to baseline. Conclusion. In subacute patients with stroke, BWSTT can lead to improved gait quality when compared with conventional gait training. Both methods can improve balance and motor function. PMID:26649295

  1. Palladium was supported on superparamagnetic nanoparticles: A magnetically recoverable catalyst for Heck reaction

    SciTech Connect

    Zhang, Fengwei; Niu, Jianrui; Wang, Haibo; Yang, Honglei; Jin, Jun; Liu, Na; Zhang, Yubin; Li, Rong; Ma, Jiantai

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Palladium-based heterogeneous catalyst was prepared facilely via the co-precipitation method. Black-Right-Pointing-Pointer The particles are nearly spherical in shape with an average size of 20 {+-} 1.0 nm. Black-Right-Pointing-Pointer The developed magnetic catalyst showed high activity for Heck reaction. Black-Right-Pointing-Pointer The catalyst was easily recovered from the reaction mixture with external magnetic field. Black-Right-Pointing-Pointer The catalytic efficiency for Heck reaction remains unaltered even after 6 repeated cycles. -- Abstract: A novel and high-performance palladium-based catalyst for Heck reaction was prepared easily by the co-precipitation method. The catalyst was characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS) and atomic absorption spectrophotometry (AAS). The catalyst afforded a fast conversion of the 4-bromonitrobenzene to 4-nitrostilbene at a catalyst loading of 5 mol%, and the efficiency of the catalyst remains unaltered even after 6 repeated cycles. The excellent catalytic performance of the Pd/Fe{sub 3}O{sub 4} catalyst might be attributed to the enhanced synergistic effect between Pd nanoparticles and magnetite.

  2. Community-wide Validation of Geospace Model Ground Magnetic Field Perturbation Predictions to Support Model Transition to Operations

    NASA Technical Reports Server (NTRS)

    Pulkkinen, A.; Rastaetter, L.; Kuznetsova, M.; Singer, H.; Balch, C.; Weimer, D.; Toth, G.; Ridley, A.; Gombosi, T.; Wiltberger, M.; Raeder, J.; Weigel, R.

    2013-01-01

    In this paper we continue the community-wide rigorous modern space weather model validation efforts carried out within GEM, CEDAR and SHINE programs. In this particular effort, in coordination among the Community Coordinated Modeling Center (CCMC), NOAA Space Weather Prediction Center (SWPC), modelers, and science community, we focus on studying the models' capability to reproduce observed ground magnetic field fluctuations, which are closely related to geomagnetically induced current phenomenon. One of the primary motivations of the work is to support NOAA SWPC in their selection of the next numerical model that will be transitioned into operations. Six geomagnetic events and 12 geomagnetic observatories were selected for validation.While modeled and observed magnetic field time series are available for all 12 stations, the primary metrics analysis is based on six stations that were selected to represent the high-latitude and mid-latitude locations. Events-based analysis and the corresponding contingency tables were built for each event and each station. The elements in the contingency table were then used to calculate Probability of Detection (POD), Probability of False Detection (POFD) and Heidke Skill Score (HSS) for rigorous quantification of the models' performance. In this paper the summary results of the metrics analyses are reported in terms of POD, POFD and HSS. More detailed analyses can be carried out using the event by event contingency tables provided as an online appendix. An online interface built at CCMC and described in the supporting information is also available for more detailed time series analyses.

  3. Evaluation of progesterone content in saliva using magnetic particle-based immuno supported liquid membrane assay (m-ISLMA).

    PubMed

    Tudorache, Madalina; Zdrojewska, Izabela Anna; Emnéus, Jenny

    2006-08-15

    Progesterone in saliva was monitored using a new method called magnetic particle-based immuno supported liquid membrane assay (m-ISLMA) in a sequential injection (SI) setup, allowing automatic sample cleanup, analyte enrichment, and detection in a single analysis unit. Progesterone (Ag) diffuses from a continuous flowing sample - the donor - into a supported organic liquid membrane (SLM), based on analyte partitioning (solubility) between the aqueous donor and the organic phase. The Ag is re-extracted from the SLM into a second stagnant aqueous acceptor, containing antibodies (Ab) immobilized on magnetic beads, held at the bottom of the acceptor by a magnet. Due to the formation of strong Ag-Ab-bead complexes and a large excess of Ab-beads, the Ag is accumulated and selectively enriched in the acceptor. The extracted progesterone was quantified by injecting into the acceptor a horseradish peroxidase (HRP) labeled analyte tracer, the substrate (luminol, H(2)O(2), and p-iodophenol), and finally detection of the generated chemiluminescence by a photomultiplier tube. After optimization of experimental parameters (e.g., sample flow rate, extraction time, type of organic solvent and antibody-bead concentration in the acceptor), a detection limit of 8.50+/-0.17 fgL(-1) and a dynamic range between 35 fgL(-1) and 10 pgL(-1) was reached. The progesterone level of saliva for three subjects (women in different period of ovarian cycle) was investigated, and the corresponding progesterone concentrations detected with m-ISLMA coincided well with the expected values. PMID:16473507

  4. Magnetic Dirac fermions and Chern insulator supported on pristine silicon surface

    NASA Astrophysics Data System (ADS)

    Fu, Huixia; Liu, Zheng; Lian, Chao; Zhang, Jin; Li, Hui; Sun, Jia-Tao; Meng, Sheng

    2016-07-01

    Emergence of ferromagnetism in nonmagnetic semiconductors is strongly desirable, especially in topological materials because of the possibility of achieving the quantum anomalous Hall effect. Based on first-principles calculations, we propose that for Si thin film grown on metal substrate, the pristine Si(111)-√{3 }×√{3 } surface with a spontaneous weak reconstruction has a strong tendency toward ferromagnetism and nontrivial topological properties, characterized by spin-polarized Dirac-fermion surface states. In contrast to conventional routes relying on introduction of alien charge carriers or specially patterned substrates, the spontaneous magnetic order and spin-orbit coupling on the pristine silicon surface together give rise to the quantized anomalous Hall effect with a finite Chern number C =-1 . This work suggests opportunities in silicon-based spintronics and quantum computing free from alien dopants or proximity effects.

  5. Structural support of a yin-yang magnet for a tandem mirror reactor with thermal barriers

    SciTech Connect

    Erickson, J.L.; Ojalvo, I.U.; Myall, J.O.

    1980-01-01

    This report contains a comprehensive summary covering work performed by Grumman Aerospace Corporation, in conjunction with the Lawrence Livermore National Laboratory, on the TMP yin-yang coils. The yin-yang coil pair used for our analysis has a major arc radius of 2.7 m and a minor arc radius of 1.18 m, compared with 2.5 m and 0.75 m for the MFTF. The maximum field on the present conductor is 9.05 Tesla. This magnetic field is created by, and interacts with, a conductor current which produces a 360 million Newton total force, tending to separate the parallel lobes of the major arcs.

  6. Fast magnetic reconnection supported by sporadic small-scale Petschek-type shocks

    SciTech Connect

    Shibayama, Takuya Nakabou, Takashi; Kusano, Kanya; Miyoshi, Takahiro; Vekstein, Grigory

    2015-10-15

    Standard magnetohydrodynamic (MHD) theory predicts reconnection rate that is far too slow to account for a wide variety of reconnection events observed in space and laboratory plasmas. Therefore, it was commonly accepted that some non-MHD (kinetic) effects play a crucial role in fast reconnection. A recently renewed interest in simple MHD models is associated with the so-called plasmoid instability of reconnecting current sheets. Although it is now evident that this effect can significantly enhance the rate of reconnection, many details of the underlying multiple-plasmoid process still remain controversial. Here, we report results of a high-resolution computer simulation which demonstrate that fast albeit intermittent magnetic reconnection is sustained by numerous small-scale Petschek-type shocks spontaneously formed in the current sheet due to its plasmoid instability.

  7. Attitude motion of a dual-spin space station supported with magnetic bearings

    NASA Astrophysics Data System (ADS)

    Nakajima, Atsushi; Ishii, Kazuhito

    A large manned space station is proposed which provides artificial gravity and microgravity environments simultaneously in separate sections. This space station is composed of a nonrotating microgravity section at the center, a rotating artificial gravity section, and a transit cabin used for transportation between them. The first section has experiment modules and the second one has habitat modules at the end of the beamlike structure extended from the rotating center body. The two sections are connected by an electromagnetic suspension mechanism; mechanically, they are separated perfectly. Therefore, the acceleration disturbance to the microgravity section from the rotating section is reduced to the level that microgravity experiments can be conducted without any trouble. The purpose of this paper is to formulate the dynamical model of this dual-spin space station and to obtain the linearized equations of motion. Computer simulations show that long-period nutational motion is attenuated by controlling the magnetic suspension system.

  8. New Magnetic Resonance Imaging Index for Renal Fibrosis Assessment: A Comparison between Diffusion-Weighted Imaging and T1 Mapping with Histological Validation

    PubMed Central

    Friedli, I.; Crowe, L. A.; Berchtold, L.; Moll, S.; Hadaya, K.; de Perrot, T.; Vesin, C.; Martin, P.-Y.; de Seigneux, S.; Vallée, J.-P.

    2016-01-01

    A need exists to noninvasively assess renal interstitial fibrosis, a common process to all kidney diseases and predictive of renal prognosis. In this translational study, Magnetic Resonance Imaging (MRI) T1 mapping and a new segmented Diffusion-Weighted Imaging (DWI) technique, for Apparent Diffusion Coefficient (ADC), were first compared to renal fibrosis in two well-controlled animal models to assess detection limits. Validation against biopsy was then performed in 33 kidney allograft recipients (KARs). Predictive MRI indices, ΔT1 and ΔADC (defined as the cortico-medullary differences), were compared to histology. In rats, both T1 and ADC correlated well with fibrosis and inflammation showing a difference between normal and diseased kidneys. In KARs, MRI indices were not sensitive to interstitial inflammation. By contrast, ΔADC outperformed ΔT1 with a stronger negative correlation to fibrosis (R2 = 0.64 against R2 = 0.29 p < 0.001). ΔADC tends to negative values in KARs harboring cortical fibrosis of more than 40%. Using a discriminant analysis method, the ΔADC, as a marker to detect such level of fibrosis or higher, led to a specificity and sensitivity of 100% and 71%, respectively. This new index has potential for noninvasive assessment of fibrosis in the clinical setting. PMID:27439482

  9. Diffusion-weighted magnetic resonance imaging for prediction of tumor response to neoadjuvant chemoradiotherapy using irinotecan plus S-1 for rectal cancer

    PubMed Central

    DOI, HIROSHI; BEPPU, NAOHITO; KATO, TAKASHI; NODA, MASASHI; YANAGI, HIDENORI; TOMITA, NAOHIRO; KAMIKONYA, NORIHIKO; HIROTA, SHOZO

    2015-01-01

    The purpose of this study was to investigate the clinical value of diffusion-weighted (DW) magnetic resonance imaging (MRI) as a predictor of tumor response in patients receiving neoadjuvant chemoradiotherapy (NA-CRT) for rectal cancer (RC) through measurement of the apparent diffusion coefficient (ADC) value in each tumor. Neoadjuvant radiotherapy with a total dose of 45 Gy in 25 fractions was performed in all 16 patients with RC, combined with irinotecan and S-1. MRI was performed before and after NA-CRT. Multiple factors were assessed to predict the pathological response to NA-CRT. The pathological response rate was determined in 9 patients (56.3%). Statistical analyses indicated that the ADC value prior to NA-CRT was significantly lower in patients with a better response to NA-CRT (P=0.023). A cut-off value of 0.750×10−3 mm2/sec obtained by a receiver operating characteristic curve analysis indicated a sensitivity of 77.8% and specificity of 85.7% for pathological responders to NA-CRT. In addition, the patients with lower ADC values exhibited a greater pathological response to NA-CRT (P=0.041). In conclusion, the ADC value of MRI of RC patients treated with NA-CRT followed by surgery may provide valuable information to predict the response to NA-CRT. PMID:26623064

  10. Predicting Cerebral Hyperperfusion Syndrome Following Superficial Temporal Artery to Middle Cerebral Artery Bypass based on Intraoperative Perfusion-Weighted Magnetic Resonance Imaging

    PubMed Central

    Wang, Defeng; Zhu, Fengping; Fung, Ka Ming; Zhu, Wei; Luo, Yishan; Chu, Winnie Chiu Wing; Tong Mok, Vincent Chung; Wu, Jinsong; Shi, Lin; Ahuja, Anil T.; Mao, Ying

    2015-01-01

    Moyamoya disease leads to the formation of stenosis in the cerebrovasculature. A superficial temporal artery to middle cerebral artery (STA-MCA) bypass is an effective treatment for the disease, yet it is usually associated with postoperative cerebral hyperperfusion syndrome (CHS). This study aimed to evaluate cerebral hemodynamic changes immediately after surgery and assess whether a semiquantitative analysis of an intraoperative magnetic resonance perfusion-weighted image (PWI) is useful for predicting postoperative CHS. Fourteen patients who underwent the STA-MCA bypass surgery were included in this study. An atlas-based registration method was employed for studying hemodynamics in different cerebral regions. Pre- versus intraoperative and group-wise comparisons were conducted to evaluate the hemodynamic changes. A postoperative increase in relative cerebral blood flow (CBF) at the terminal MCA territory (P = 0.035) and drop in relative mean-time-transit at the central MCA territory (P = 0.012) were observed in all patients. However, a significant raise in the increasing ratio of relative-CBF at the terminal MCA territory was only found in CHS patients (P = 0.023). The cerebrovascular changes of the patients after revascularization treatment were confirmed. Intraoperative PWI might be helpful in predicting the change in relative-CBF at MCA terminal territory which might indicate a risk of CHS. PMID:26365751

  11. In vivo evaluation of brain damage in the course of systemic lupus erythematosus using magnetic resonance spectroscopy, perfusion-weighted and diffusion-tensor imaging.

    PubMed

    Zimny, A; Szmyrka-Kaczmarek, M; Szewczyk, P; Bladowska, J; Pokryszko-Dragan, A; Gruszka, E; Wiland, P; Sasiadek, M

    2014-01-01

    Twenty-two neuropsychiatric (NPSLE) and 13 systemic lupus erythematosus (SLE) patients with a normal appearing brain on plain magnetic resonance (MR) as well as 20 age-matched healthy controls underwent MR spectroscopy (MRS), perfusion-weighted (PWI) and diffusion-tensor imaging (DTI). In MRS NAA/Cr, Cho/Cr and mI/Cr ratios were calculated from the posterior cingulate cortex and left parietal white matter. In PWI, values of cerebral blood volume (CBV) were assessed from 14 regions, including gray and white matter. In DTI fractional anisotropy (FA) values were obtained from 14 white matter tracts including projection, commissural and association fibers. All MR measurements were correlated with clinical data. SLE and NPSLE patients showed significantly (p < 0.05) lower NAA/Cr ratios within both evaluated regions and FA values within the cingulum, as well as a tendency to cortical hypoperfusion. Compared to SLE, NPSLE subjects revealed lower FA values within a wide range of association fibers and corpus callosum. Advanced MR techniques are capable of in vivo detection of complex microstructural brain damage in SLE and NPSLE subjects regarding neuronal loss, mild hypoperfusion and white matter disintegrity. MRS and DTI seem to show the highest usefulness in depicting early changes in normal appearing gray and white matter in SLE patients. PMID:24192079

  12. Development of Computerized Scheme for Adjustment of Display Grayscale in Brain Diffusion-Weighted Magnetic Resonance Images with Acute Ischemic Stroke

    NASA Astrophysics Data System (ADS)

    Nagashima, Hiroyuki; Harakawa, Tetsumi; Doi, Kunio

    We developed a computerized scheme for proper adjustment of display grayscale in brain diffusion-weighted magnetic resonance images (DWI) with acute ischemic stroke by using thalamic signal intensity on concurrent images (b0 image). In our computerized scheme, the gray level of b0 image was first normalized, and the brain region was segmented using thresholding and labeling techniques. The lateral inclination in b0 image was then corrected semi-automatically by rotating and shifting. Each of the thalamic positions was determined by using the coordinate information in the brain region. The average signal intensity of the thalamus was measured on the region of interest (ROI) selected, and the thalamus in one side with the low signal intensity was selected. The display grayscale in DWI was finally adjusted by using the signal intensity of the selected thalamus. The thalamus positions in all cases were confirmed to be included in the thalamic outline. In 30 training cases, the average error between the thalamic signal intensity obtained from the manual selection and the computerized scheme were 1.8%±1.5, and in 30 testing cases, 1.3%±1.2. Our computerized scheme has a potential in the determination of the display grayscale of brain DWI, and would be useful to radiologists in decision-making for radiological diagnosis.

  13. New Magnetic Resonance Imaging Index for Renal Fibrosis Assessment: A Comparison between Diffusion-Weighted Imaging and T1 Mapping with Histological Validation.

    PubMed

    Friedli, I; Crowe, L A; Berchtold, L; Moll, S; Hadaya, K; de Perrot, T; Vesin, C; Martin, P-Y; de Seigneux, S; Vallée, J-P

    2016-01-01

    A need exists to noninvasively assess renal interstitial fibrosis, a common process to all kidney diseases and predictive of renal prognosis. In this translational study, Magnetic Resonance Imaging (MRI) T1 mapping and a new segmented Diffusion-Weighted Imaging (DWI) technique, for Apparent Diffusion Coefficient (ADC), were first compared to renal fibrosis in two well-controlled animal models to assess detection limits. Validation against biopsy was then performed in 33 kidney allograft recipients (KARs). Predictive MRI indices, ΔT1 and ΔADC (defined as the cortico-medullary differences), were compared to histology. In rats, both T1 and ADC correlated well with fibrosis and inflammation showing a difference between normal and diseased kidneys. In KARs, MRI indices were not sensitive to interstitial inflammation. By contrast, ΔADC outperformed ΔT1 with a stronger negative correlation to fibrosis (R(2) = 0.64 against R(2) = 0.29 p < 0.001). ΔADC tends to negative values in KARs harboring cortical fibrosis of more than 40%. Using a discriminant analysis method, the ΔADC, as a marker to detect such level of fibrosis or higher, led to a specificity and sensitivity of 100% and 71%, respectively. This new index has potential for noninvasive assessment of fibrosis in the clinical setting. PMID:27439482

  14. A study of the relationship between gender/age and apparent diffusion coefficient values in spleen of healthy adults using diffusion-weighted magnetic resonance imaging

    PubMed Central

    Nazarlou, Ali Kiani; Abdolmohammadi, Jamil

    2015-01-01

    Background: Diffusion-weighted magnetic resonance imaging (DWI) systems are very effective in detecting strokes, and they also have shown significant promise in the detection of fibrosis and cirrhosis of the liver. However, such systems have the disadvantages of poor reproducibility and noise, which can diminish the accuracy of the apparent diffusion coefficients (ADCs) provided by the DWI process. The main aim of this study was to determine the relationship between the age and gender of healthy adults in terms of the ADC values of the spleen measured by DWI. Methods: Sixty-nine subjects selected for this study from people who were referred to the Tabesh Medical Imaging Center in Tabriz, Iran, in 2013. Each subject underwent echo-planar DWI for her or his ADC values of the spleen with b-values of 50, 400, and 800 s/mm2, and the resulting ADC values were evaluated. Results: No significant differences were observed in ADC values of the spleen among the female and male participants or those from various ages (P>0.05). Conclusions: Based on the findings of this study, it was concluded that the effect of age and gender on the spleen’s ADC values can be omitted from the spleen-diagnosis procedure. In other words, the spleen’s ADC values are not related to the age or the gender of healthy adults. PMID:26052412

  15. Prizes for weight loss.

    PubMed Central

    Englberger, L.

    1999-01-01

    A programme of weight loss competitions and associated activities in Tonga, intended to combat obesity and the noncommunicable diseases linked to it, has popular support and the potential to effect significant improvements in health. PMID:10063662

  16. Body Weight

    MedlinePlus

    ... heart failure, and kidney disease. Good nutrition and exercise can help in losing weight. Eating extra calories within a well-balanced diet and treating any underlying medical problems can help to add weight.

  17. Weight Control

    MedlinePlus

    ... obese. Achieving a healthy weight can help you control your cholesterol, blood pressure and blood sugar. It ... use more calories than you eat. A weight-control strategy might include Choosing low-fat, low-calorie ...

  18. Body Weight

    MedlinePlus

    ... to medicines, thyroid problems, heart failure, and kidney disease. Good nutrition and exercise can help in losing weight. Eating extra calories within a well-balanced diet and treating any underlying medical problems can help to add weight.

  19. Alternative concepts for structurally supporting the cold mass of a superconducting accelerator magnet

    SciTech Connect

    Sondericker, J.H. ); Wolf, L.J. )

    1991-03-01

    Experimental and analytical studies toward the goal of replacing the fiberglass reentrant support posts and their end restraint systems with lower cost injection molded posts are described. Thermoplastic resins with chopped fiberglass reinforcement having lower thermal conductivity were investigated. Experimentally obtained data from creep, shear, and tensile tests on actual injection molded posts of Ultem and Noryl are included. Discussion of flaws and quality control is included. These studies for the Relativistic Heavy Ion Collider (RHIC) and the Superconducting Super Collider (SSC) are continuing at Brookhaven National Laboratory and at the SSC Laboratory. 6 refs., 13 figs.

  20. A dynamically collapsing core and a precursor of a core in a filament supported by turbulent and magnetic pressures

    SciTech Connect

    Furuya, Ray S.; Kitamura, Yoshimi; Shinnaga, Hiroko E-mail: kitamura@isas.jaxa.jp

    2014-10-01

    To study physical properties of the natal filament gas around the cloud core harboring an exceptionally young low-mass protostar GF 9-2, we carried out J = 1-0 line observations of {sup 12}CO, {sup 13}CO, and C{sup 18}O molecules using the Nobeyama 45 m telescope. The mapping area covers ∼ one-fifth of the whole filament. Our {sup 13}CO and C{sup 18}O maps clearly demonstrate that the core formed at the local density maxima of the filament, and the internal motions of the filament gas are totally governed by turbulence with Mach number of ∼2. We estimated the scale height of the filament to be H = 0.3-0.7 pc, yielding the central density of n {sub c} = 800-4200 cm{sup –3}. Our analysis adopting an isothermal cylinder model shows that the filament is supported by the turbulent and magnetic pressures against the radial and axial collapse due to self-gravity. Since both the dissipation timescales of the turbulence and the transverse magnetic fields can be comparable to the free-fall time of the filament gas of 10{sup 6} yr, we conclude that the local decay of the supersonic turbulence and magnetic fields made the filament gas locally unstable, hence making the core collapse. Furthermore, we newly detected a gas condensation with velocity width enhancement to ∼0.3 pc southwest of the GF 9-2 core. The condensation has a radius of ∼0.15 pc and an LTE mass of ∼5 M {sub ☉}. Its internal motion is turbulent with Mach number of ∼3, suggesting a gravitationally unbound state. Considering the uncertainties in our estimates, however, we propose that the condensation is a precursor of a cloud core, which would have been produced by the collision of the two gas components identified in the filament.

  1. A Dynamically Collapsing Core and a Precursor of a Core in a Filament Supported by Turbulent and Magnetic Pressures

    NASA Astrophysics Data System (ADS)

    Furuya, Ray S.; Kitamura, Yoshimi; Shinnaga, Hiroko

    2014-10-01

    To study physical properties of the natal filament gas around the cloud core harboring an exceptionally young low-mass protostar GF 9-2, we carried out J = 1-0 line observations of 12CO, 13CO, and C18O molecules using the Nobeyama 45 m telescope. The mapping area covers ~ one-fifth of the whole filament. Our 13CO and C18O maps clearly demonstrate that the core formed at the local density maxima of the filament, and the internal motions of the filament gas are totally governed by turbulence with Mach number of ~2. We estimated the scale height of the filament to be H = 0.3-0.7 pc, yielding the central density of n c = 800-4200 cm-3. Our analysis adopting an isothermal cylinder model shows that the filament is supported by the turbulent and magnetic pressures against the radial and axial collapse due to self-gravity. Since both the dissipation timescales of the turbulence and the transverse magnetic fields can be comparable to the free-fall time of the filament gas of 106 yr, we conclude that the local decay of the supersonic turbulence and magnetic fields made the filament gas locally unstable, hence making the core collapse. Furthermore, we newly detected a gas condensation with velocity width enhancement to ~0.3 pc southwest of the GF 9-2 core. The condensation has a radius of ~0.15 pc and an LTE mass of ~5 M ⊙. Its internal motion is turbulent with Mach number of ~3, suggesting a gravitationally unbound state. Considering the uncertainties in our estimates, however, we propose that the condensation is a precursor of a cloud core, which would have been produced by the collision of the two gas components identified in the filament.

  2. A Comprehensive C++ Controller for a Magnetically Supported Vertical Rotor. 1.0

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.

    2001-01-01

    This manual describes the new FATMaCC (Five-Axis, Three-Magnetic-Bearing Control Code). The FATMaCC (pronounced "fat mak") is a versatile control code that possesses many desirable features that were not available in previous in-house controllers. The ultimate goal in designing this code was to achieve full rotor levitation and control at a loop time of 50 microsec. Using a 1-GHz processor, the code will control a five-axis system in either a decentralized or a more elegant centralized (modal control) mode at a loop time of 56 microsec. In addition, it will levitate and control (with only minor modification to the input/output wiring) a two-axis and/or a four-axis system. Stable rotor levitation and control of any of the systems mentioned above are accomplished through appropriate key presses to modify parameters, such as stiffness, damping, and bias. A signal generation block provides 11 excitation signals. An excitation signal is then superimposed on the radial bearing x- and y-control signals, thus producing a resultant force vector. By modulating the signals on the bearing x- and y-axes with a cosine and a sine function, respectively, a radial excitation force vector is made to rotate 360 deg. about the bearing geometric center. The rotation of the force vector is achieved manually by using key press or automatically by engaging the "one-per-revolution" feature. Rotor rigid body modes can be excited by using the excitation module. Depending on the polarities of the excitation signal in each radial bearing, the bounce or tilt mode will be excited.

  3. High Speed, High Temperature, Fault Tolerant Operation of a Combination Magnetic-Hydrostatic Bearing Rotor Support System for Turbomachinery

    NASA Technical Reports Server (NTRS)

    Jansen, Mark; Montague, Gerald; Provenza, Andrew; Palazzolo, Alan

    2004-01-01

    Closed loop operation of a single, high temperature magnetic radial bearing to 30,000 RPM (2.25 million DN) and 540 C (1000 F) is discussed. Also, high temperature, fault tolerant operation for the three axis system is examined. A novel, hydrostatic backup bearing system was employed to attain high speed, high temperature, lubrication free support of the entire rotor system. The hydrostatic bearings were made of a high lubricity material and acted as journal-type backup bearings. New, high temperature displacement sensors were successfully employed to monitor shaft position throughout the entire temperature range and are described in this paper. Control of the system was accomplished through a stand alone, high speed computer controller and it was used to run both the fault-tolerant PID and active vibration control algorithms.

  4. A highly sensitive quartz crystal microbalance immunosensor based on magnetic bead-supported bienzymes catalyzed mass enhancement strategy.

    PubMed

    Akter, Rashida; Rhee, Choong Kyun; Rahman, Md Aminur

    2015-04-15

    A highly sensitive quartz crystal microbalance (QCM) immunosensor based on magnetic bead-supported bienzyme catalyzed mass enhanced strategy was developed for the detection of human immunoglobulin G (hIgG) protein. The high sensitive detection was achieved by increasing the deposited mass on the QCM crystal through the enhanced precipitation of 4-chloro-1-naphthol (CN) using higher amounts of horseradish peroxidase (HRP) and glucose oxidase (GOx) bienzymes attached on the magnetic beads (MB). The protein A (PA) and capture antibody (monoclonal anti-human IgG antibody produced in mouse, Ab1)-based QCM probe and the detection antibody (anti-human IgG antibody produced in goat, Ab2)-based MB/HRP/GOx bienzymatic bioconjugates were characterized using scanning electron microscope, transmission electron microscope, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. Under the optimized experimental condition, the linear range and the detection limit of hIgG immunosensor were determined to be 5.0pg/mL-20.0ng/mL and 5.0±0.18pg/mL, respectively. The applicability of the present hIgG immunosensor was examined in hIgG spiked human serum samples and excellent recoveries of hIgG were obtained. PMID:25506902

  5. Quantitative diffusion-weighted magnetic resonance imaging in the assessment of myocardial fibrosis in hypertrophic cardiomyopathy compared with T1 mapping.

    PubMed

    Wu, Lian-Ming; Chen, Bing-Hua; Yao, Qiu-Ying; Ou, Yang-Rongzheng; Wu, Rui; Jiang, Meng; Hu, Jiani; An, Dong-Aolei; Xu, Jian-Rong

    2016-08-01

    To identify myocardial fibrosis in hypertrophic cardiomyopathy (HCM) subjects using quantitative cardiac diffusion-weighted imaging (DWI) and to compare its performance with native T1 mapping and extracellular volume (ECV). Thirty-eight HCM subjects (mean age, 53 ± 9 years) and 14 normal controls (mean age, 51 ± 8 years) underwent cardiac magnetic resonance imaging (CMRI) on a 3.0T magnetic resonance (MR) machine with DWI, T1 mapping and late gadolinium enhancement (LGE) imaging as the reference standard. The mean apparent diffusion coefficient (ADC), native T1 value and ECV were determined for each subject. Overall, the HCM subjects exhibited an increased native T1 value (1241.04 ± 78.50 ms), ECV (0.31 ± 0.03) and ADC (2.36 ± 0.34 s/mm(2)) compared with the normal controls (1114.60 ± 37.99 ms, 0.24 ± 0.04, and 1.62 ± 0.38 s/mm(2), respectively) (p < 0.05). DWI differentiated healthy and fibrotic myocardia with an area under the curve (AUC) of 0.93, while the AUCs of the native T1 values (0.93), (p > 0.05) and ECV (0.94), (p > 0.05) exhibited an equal differentiation ability. Both HCM LGE+ and HCM LGE- subjects had an increased native T1 value, ECV and ADC compared to the normal controls (p < 0.05). HCM LGE+ subjects exhibited an increased ECV (0.31 ± 0.04) and ADC (2.43 ± 0.36 s/mm(2)) compared to HCM LGE- subjects (p < 0.05). HCM LGE+ and HCM LGE- subjects had similar native T1 values (1250 ± 76.36 ms vs. 1213.98 ± 92.30 ms, respectively) (p > 0.05). ADC values were linearly associated with increased ECV (R(2) = 0.36) and native T1 values (R(2) = 0.40) among all subjects. DWI is a feasible alternative to native T1 mapping and ECV for the identification of myocardial fibrosis in patients with HCM. DWI and ECV can quantitatively characterize the extent of fibrosis in HCM LGE+ and HCM LGE- patients. PMID:27198892

  6. Streptavidin-modified monodispersed magnetic poly(2-hydroxyethyl methacrylate) microspheres as solid support in DNA-based molecular protocols.

    PubMed

    Salih, Tagrid; Ahlford, Annika; Nilsson, Mats; Plichta, Zdeněk; Horák, Daniel

    2016-04-01

    Molecular diagnostics may provide tailored and cost efficient treatment for infectious disease and cancer. Rolling circle amplification (RCA) of padlock probes guarantees high specificity to identify nucleic acid targets down to single nucleotide resolution in a multiplex fashion. This makes the assay suitable for molecular analysis of various diseases, and interesting to integrate into automated devices for point-of-care analysis. A critical prerequisite for many molecular assays is (i) target-specific isolation from complex clinical samples and (ii) removal of reagents, inhibitors and contaminants between reaction steps. Efficient solid supports are therefore essential to enable multi-step, multi-analyte protocols. Superparamagnetic micro- and nanoparticles, with large surface area and rapid liquid-phase kinetics, are attractive for multi-step protocols. Recently, streptavidin-modified magnetic monodispersed poly(2-hydroxyethyl methacrylate) (STV-mag.PHEMA) microspheres were developed by multiple swelling polymerization. They are easily separated by a magnet and exhibit low non-specific protein sorption. In this study, the performance and the binding efficiency of STV-mag.PHEMA was addressed by circle-to-circle amplification (C2CA). A lower number of RCA products were detected as compared to the gold standard Dynabeads. Nevertheless, this study was the first to successfully adapt STV-mag.PHEMA microspheres as solid support in a DNA-based protocol, which is an important finding. The STV-mag.PHEMA microspheres were larger with about 16 times less surface area as compared to the Dynabeads, which might partly explain the lower rolling circle product (RCP) count obtained. Further research is currently ongoing comparing particles of similar sizes and optimizing reaction conditions to establish their full utility in the field. Ultimately, low cost and versatile particles are a great resource to facilitate future clinical molecular diagnostics. PMID:26838862

  7. Quantification of red myotomal muscle volume and geometry in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis) using T1-weighted magnetic resonance imaging.

    PubMed

    Perry, Cameron N; Cartamil, Daniel P; Bernal, Diego; Sepulveda, Chugey A; Theilmann, Rebecca J; Graham, Jeffrey B; Frank, Lawrence R

    2007-04-01

    T1-weighted magnetic resonance imaging (MRI) in conjunction with image and segmentation analysis (i.e., the process of digitally partitioning tissues based on specified MR image characteristics) was evaluated as a noninvasive alternative for differentiating muscle fiber types and quantifying the amounts of slow, red aerobic muscle in the shortfin mako shark (Isurus oxyrinchus) and the salmon shark (Lamna ditropis). MRI-determinations of red muscle quantity and position made for the mid-body sections of three mako sharks (73.5-110 cm fork length, FL) are in close agreement (within the 95% confidence intervals) with data obtained for the same sections by the conventional dissection method involving serial cross-sectioning and volumetric analyses, and with previously reported findings for this species. The overall distribution of salmon shark red muscle as a function of body fork length was also found to be consistent with previously acquired serial dissection data for this species; however, MR imaging revealed an anterior shift in peak red muscle cross-sectional area corresponding to an increase in body mass. Moreover, MRI facilitated visualization of the intact and anatomically correct relationship of tendon linking the red muscle and the caudal peduncle. This study thus demonstrates that MRI is effective in acquiring high-resolution three-dimensional digital data with high contrast between different fish tissue types. Relative to serial dissection, MRI allows more precise quantification of the position, volume, and other details about the types of muscle within the fish myotome, while conserving specimen structural integrity. PMID:17299779

  8. Texture-based characterization of pre- and post-operative T2-weighted magnetic resonance signals of the cervical spinal cord in cervical spondylotic myelopathy

    NASA Astrophysics Data System (ADS)

    Boniatis, Ioannis; Klironomos, George; Gatzounis, George; Panayiotakis, George

    2009-10-01

    The utility of texture analysis regarding the provision of quantitative prognostic factors, potentially valuable to the prediction of the post-operative outcome of cervical spondylotic myelopathy (CSM) patients, is investigated. The clinical sample of the study comprised six subjects, who had undergone surgical therapeutic intervention for CSM. Following a specific imaging protocol, a pair of MR images of the cervical spine, corresponding to pre- and post-operative MR scans, was obtained for each of the patients. Accordingly, 12 sagittal T2-weighted magnetic resonance (MR) images were studied. Employing custom developed software, a Region Of Interest (ROI) within the spinal cord, corresponding to the region of the high-intensity CSM MR signal, was segmented on each image, according to the region growing method. Utilizing custom developed algorithms, the following sets of textural features were generated from the segmented ROIs: (i) gradient features, (ii) mean values of features from co-occurrence matrices (co-occurrence features) and (iii) range values of co-occurrence features. Utilizing each one of these sets of features, as well as the least-squares minimum distance and the quadratic classification algorithms, pattern recognition classification schemes were implemented for the discrimination between pre-operative and post-operative MR signals. Statistical analysis revealed the existence of statistically significant differences (p < 0.05) between textural features generated from pre-operative and post-operative high-intensity MR signals. The classification accuracies accomplished ranged from 75% to 100%. Textural features, descriptive of relevant properties of the high-intensity MR signal in CSM, may be considered as quantitative information of potential value for the prediction of the post-operative outcome of CSM patients.

  9. Contrast-enhanced magnetic resonance pancreatography with gadoteridol by heavily T2-weighted three-dimensional fluid-attenuated inversion recovery: preliminary results in healthy subjects

    PubMed Central

    Suzuki, Kojiro; Naganawa, Shinji; Furuhashi, Naohiro; Yamazaki, Masahiro; Ogawa, Hiroshi; Kawai, Hisashi

    2016-01-01

    ABSTRACT The purpose of this study was to investigate the feasibility of contrast-enhanced magnetic resonance (MR) pancreatography with intravenously administered gadolinium-based contrast material (GBCM) in healthy subjects. Eight healthy male subjects (age: 29–53 years old, median: 37 years old) were enrolled. Contrast-enhanced MR pancreatography was scanned with heavily T2-weighted three-dimensional fluid-attenuated inversion recovery (hT2W-3D-FLAIR) before and after intravenous GBCM administration. Two radiologists evaluated the images, referring to three-dimensional MR pancreatography by consensus. Scanning was performed five times at 1.5-h intervals (at 0.5, 2, 3.5, 5, and 6.5 h) after GBCM administration. In all subjects, pre-contrast-enhanced hT2W-3D-FLAIR images demonstrated no visualization of the main pancreatic duct. After GBCM administration, the main pancreatic duct was visualized in all subjects at 0.5 h (n=4, 50%) and/or 2 h (n=7, 88%). The mean signal intensity of the main pancreatic duct was 3.17 ± 0.78 at pre-contrast enhancement, 7.96 ± 4.60 at 0.5 h, and 8.08 ± 4.64 at 2 h. The signal intensity ratio of the main pancreatic duct against the pancreatic parenchyma was statistically higher (P < 0.01) at the 0.5-h and 2-h scans than that of pre-contrast-enhanced scan. Intravenously administered GBCM seeped into the pancreatic duct in sufficient concentration to alter the appearance of the main pancreatic duct by hT2W-3D-FLAIR in healthy subjects. PMID:27303104

  10. The Role of Diffusion-Weighted Magnetic Resonance Imaging in the Treatment Response Evaluation of Hepatocellular Carcinoma Patients Treated With Radiation Therapy

    SciTech Connect

    Yu, Jeong Il; Park, Hee Chul; Lim, Do Hoon; Choi, Yunseon; Jung, Sang Hoon; Paik, Seung Woon; Kim, Seong Hyun; Jeong, Woo Kyoung; Kim, Young Kon

    2014-07-15

    Purpose: We investigated the role of diffusion-weighted magnetic resonance imaging (DW MRI) as a response evaluation indicator for hepatocellular carcinoma (HCC) treated with radiation therapy (RT). Methods and Materials: Inclusion criteria of this retrospective study were DW MRI acquisition within 1 month before and 3 to 5 months after RT. In total, 48 patients were enrolled. Two radiation oncologists measured the apparent diffusion coefficient (ADC). Possible predictive factors, including alteration of the ADC value before and 3 to 5 month after RT, in relation to local progression-free survival (LPFS) were analyzed and compared. Results: Three months after RT, 6 patients (12.5%) showed a complete response, and 27 patients (56.3%) showed a partial response when evaluated using the modified response evaluation criteria in solid tumors (mRECIST). The average ADC ± SD values were 1.21 ± 0.27 ( × 10{sup −3} mm{sup 2}/s) before and 1.41 ± 0.36 ( × 10{sup −3} mm{sup 2}/s) after RT (P<.001). The most significant prognostic factor related to LPFS was mRECIST (P<.001). The increment of ADC value (≥20%) was also a significant factor (P=.02), but RECIST (version 1.1; P=.11) was not. When RECIST was combined with the increment of ADC value (≥20%), the LPFS rates were significantly different between the groups (P=.004), and the area under the curve value (0.745) was comparable with that of mRECIST (0.765). Conclusions: ADC value change before and after RT in HCC was closely related to LPFS. ADC value and RECIST may substitute for mRECIST in patients who cannot receive contrast agents.

  11. Evaluation of Cranial and Cervical Arteries and Brain Tissue in Transient Ischemic Attack Patients with Magnetic Resonance Angiography and Diffusion-Weighted Imaging

    PubMed Central

    Li, Jian-Long; Li, Chang-Shan; Fu, Jun-Hua; Zhang, Ke; Xu, Rui; Xu, Wen-Jian

    2015-01-01

    Background Magnetic resonance angiography (MRA) and diffusion-weighted imaging (DWI) have been widely used in the prediction of ischemic stroke; however, the differences of the 2 methods in detection the artery lesion differences between transient ischemic attack (TIA) and infarction patients have been long neglected. We performed the present study to investigate the differences between vessel characteristics detected by MRA and DWI in acute stroke and TIA patients. Material/Methods We classified 110 subjects into 2 groups and all the patients underwent both MRA and DWI. The degree of stenosis of cranial and cervical arteries, the distribution of the stenosis, the development and changes of the vessels, and the DWI scanning results of the brain tissue were all analyzed. Results We detected a significant difference in the number and the degree of stenosis of cranial and cervical arteries among the 3 groups (P=0.006). Compared with health controls, patients with TIA and cerebral infraction had much more severe stenosis and occlusive arteries (P<0.05). However, no significant difference was detected between TIA and cerebral infraction patients (P=0.148). Moreover, a higher rate of unilateral vertebral artery dysplasia was found in the vertebrobasilar TIA patients. Higher lesion signals were also observed by DWI in TIA patients of internal carotid artery system (4/8, 50%). Conclusions Vessel characteristics were not significantly different between TIA and infarction patients. Unilateral vertebral artery hypoplasia was a predisposing factor for vertebrobasilar TIA and ischemic focus in DWI detection was always caused by severe artery lesions. PMID:26073092

  12. Dynamic Spin Rig Upgraded With a Five- Axis-Controlled Three-Magnetic-Bearing Support System With Forward Excitation

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.; Mehmed, Oral

    2003-01-01

    The NASA Glenn Research Center Dynamic Spin Rig is used for experimental evaluation of vibration analysis methods and dynamic characteristics for rotating systems. Measurements are made while rotors are spun and vibrated in a vacuum chamber. The rig has been upgraded with a new active magnetic bearing rotor support and excitation system. This design is expected to provide operational improvements over the existing rig. The rig will be able to be operated in either the old or new configuration. In the old configuration, two ball bearings support the vertical shaft of the rig, with the test article located between the bearings. Because the bearings operate in a vacuum, lubrication is limited to grease. This limits bearing life and speed. In addition, the old configuration employs two voice-coil electromagnetic shakers to apply oscillatory axial forces or transverse moments to the rotor shaft through a thrust bearing. The excitation amplitudes that can be imparted to the test article with this system are not adequate for components that are highly damped. It is expected that the new design will overcome these limitations.

  13. MAGNETS

    DOEpatents

    Hofacker, H.B.

    1958-09-23

    This patent relates to nmgnets used in a calutron and more particularly to means fur clamping an assembly of magnet coils and coil spacers into tightly assembled relation in a fluid-tight vessel. The magnet comprises windings made up of an assembly of alternate pan-cake type coils and spacers disposed in a fluid-tight vessel. At one end of the tank a plurality of clamping strips are held firmly against the assembly by adjustable bolts extending through the adjacent wall. The foregoing arrangement permits taking up any looseness which may develop in the assembly of coils and spacers.

  14. Weight Management

    MedlinePlus

    ... Quit Smoking Benefits of Quitting Health Effects of Smoking Secondhand Smoke Withdrawal Ways to Quit QuitGuide Pregnancy & Motherhood Pregnancy & Motherhood Before Your Baby is Born From Birth to 2 Years Quitting for Two SmokefreeMom Healthy Kids Parenting & ... Weight Management Weight Management ...

  15. Minimum Weight Design of a Leaf Spring Tapered in Thickness and Width for the Hubble Space Telescope-Space Support Equipment

    NASA Technical Reports Server (NTRS)

    Rodriguez, P. I.

    1990-01-01

    A linear elastic solution to the problem of minimum weight design of cantilever beams with variable width and depth is presented. The solution shown is for the specific application of the Hubble Space Telescope maintenance mission hardware. During these maintenance missions, delicate instruments must be isolated from the potentially damaging vibration environment of the space shuttle cargo bay during the ascent and descent phases. The leaf springs are designed to maintain the isolation system natural frequency at a level where load transmission to the instruments in a minimum. Nonlinear programming is used for the optimization process. The weight of the beams is the objective function with the deflection and allowable bending stress as the constraint equations. The design variables are the width and depth of the beams at both the free and the fixed ends.

  16. Effectiveness of a mHealth Lifestyle Program With Telephone Support (TXT2BFiT) to Prevent Unhealthy Weight Gain in Young Adults: Randomized Controlled Trial

    PubMed Central

    Partridge, Stephanie R; McGeechan, Kevin; Hebden, Lana; Balestracci, Kate; Wong, Annette TY; Denney-Wilson, Elizabeth; Harris, Mark F; Phongsavan, Philayrath; Bauman, Adrian

    2015-01-01

    Background Weight gained in young adulthood often persists throughout later life with associated chronic disease risk. Despite this, current population prevention strategies are not specifically designed for young adults. Objective We designed and assessed the efficacy of an mHealth prevention program, TXT2BFiT, in preventing excess weight gain and improving dietary and physical activity behaviors in young adults at increased risk of obesity and unhealthy lifestyle choices. Methods A two-arm, parallel-group randomized controlled trial was conducted. Subjects and analyzing researchers were blinded. A total of 250 18- to 35-year-olds with a high risk of weight gain, a body mass index (BMI) of 23.0 to 24.9 kg/m2 with at least 2 kg of weight gain in the previous 12 months, or a BMI of 25.0 to 31.9 kg/m2 were randomized to the intervention or control group. In the 12-week intervention period, the intervention group received 8 text messages weekly based on the transtheoretical model of behavior change, 1 email weekly, 5 personalized coaching calls, a diet booklet, and access to resources and mobile phone apps on a website. Control group participants received only 4 text messages and printed dietary and physical activity guidelines. Measured body weight and height were collected at baseline and at 12 weeks. Outcomes were assessed via online surveys at baseline and at 12 weeks, including self-reported weight and dietary and physical activity measures. Results A total of 214 participants—110 intervention and 104 control—completed the 12-week intervention period. A total of 10 participants out of 250 (4.0%)—10 intervention and 0 control—dropped out, and 26 participants (10.4%)—5 intervention and 21 control—did not complete postintervention online surveys. Adherence to coaching calls and delivery of text messages was over 90%. At 12 weeks, the intervention group were 2.2 kg (95% CI 0.8-3.6) lighter than controls (P=.005). Intervention participants consumed more

  17. Assessing the Early Response of Advanced Cervical Cancer to Neoadjuvant Chemotherapy Using Intravoxel Incoherent Motion Diffusion-weighted Magnetic Resonance Imaging: A Pilot Study

    PubMed Central

    Wang, Yan-Chun; Hu, Dao-Yu; Hu, Xue-Mei; Shen, Ya-Qi; Meng, Xiao-Yan; Tang, Hao; Li, Zhen

    2016-01-01

    Background: Diffusion-weighted imaging (DWI) with the intravoxel incoherent motion (IVIM) model has shown promising results for providing both diffusion and perfusion information in cervical cancer; however, its use to predict and monitor the efficacy of neoadjuvant chemotherapy (NACT) in cervical cancer is relatively rare. The study aimed to evaluate the use of DWI with IVIM and monoexponential models to predict and monitor the efficacy of NACT in cervical cancer. Methods: Forty-two patients with primary cervical cancer underwent magnetic resonance exams at 3 time points (pre-NACT, 3 weeks after the first NACT cycle, and 3 weeks after the second NACT cycle). The response to treatment was determined according to the response evaluation criteria in solid tumors 3 weeks after the second NACT treatment, and the subjects were classified as two groups: responders and nonresponders groups. The apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion-related pseudo-diffusion coefficient (D*), and perfusion fraction (f) values were determined. The differences in IVIM-derived variables and ADC between the different groups at the different time points were calculated using an independent samples t-test. Results: The D and ADC values were all significantly higher for the responders than for the nonresponders at all 3 time points, but no significant differences were observed in the D* and f values. An analysis of the receiver operating characteristic (ROC) curves indicated that a D value threshold <0.93 × 10−3 mm2/s and an ADC threshold <1.11 × 10−3 mm2/s could differentiate responders from nonresponders at pre-NACT time point, yielding area under the curve (AUC) of which were 0.771 and 0.806, respectively. The ROC indicated that the AUCs of D and ADC at the 3 weeks after the first NACT cycle and 3 weeks after the second NACT cycle were 0.823, 0.763, and 0.787, 0.794, respectively. The AUC values of D and ADC at these 3 time points were not

  18. Value of Diffusion-Weighted Magnetic Resonance Imaging for Prediction and Early Assessment of Response to Neoadjuvant Radiochemotherapy in Rectal Cancer: Preliminary Results

    SciTech Connect

    Lambrecht, Maarten; Vandecaveye, Vincent; De Keyzer, Frederik; Roels, Sarah; Penninckx, Freddy; Van Cutsem, Eric; Filip, Claus; Haustermans, Karin

    2012-02-01

    Purpose: To evaluate diffusion-weighted magnetic resonance imaging (DWI) for response prediction before and response assessment during and early after preoperative radiochemotherapy (RCT) for locally advanced rectal cancer (LARC). Methods and Materials: Twenty patients receiving RCT for LARC underwent MRI including DWI before RCT, after 10-15 fractions and 1 to 2 weeks before surgery. Tumor volume and apparent diffusion coefficient (ADC; b-values: 0-1000 s/mm{sup 2}) were determined at all time points. Pretreatment tumor ADC and volume, tumor ADC change ( Increment ADC), and volume change ( Increment V) between pretreatment and follow-up examinations were compared with histopathologic findings after total mesorectal excision (pathologic complete response [pCR] vs. no pCR, ypT0-2 vs. ypT3-4, T-downstaging or not). The discriminatory capability of pretreatment tumor ADC and volume, Increment ADC, and Increment V for the detection of pCR was compared with receiver operating characteristics analysis. Results: Pretreatment ADC was significantly lower in patients with pCR compared with patients without (in mm{sup 2}/s: 0.94 {+-} 0.12 Multiplication-Sign 10{sup -3} vs. 1.19 {+-} 0.22 Multiplication-Sign 10{sup -3}, p = 0.003), yielding a sensitivity of 100% and specificity of 86% for detection of pCR. The volume reduction during and after RCT was significantly higher in patients with pCR compared with patients without (in %: {Delta}V{sub during}: -62 {+-} 16 vs. -33 {+-} 16, respectively, p = 0.015; and {Delta}V{sub post}: -86 {+-} 12 vs. -60 {+-} 21, p = 0.012), yielding a sensitivity of 83% and specificity of 71% for the {Delta}V{sub during} and, respectively, 83% and 86% for the {Delta}V{sub post}. The Increment ADC during ({Delta}ADC{sub during}) and after RCT ({Delta}ADC{sub post}) showed a significantly higher value in patients with pCR compared with patients without (in %: {Delta}ADC{sub during}: 72 {+-} 14 vs. 16 {+-} 12, p = 0.0006; and {Delta}ADC{sub post}: 88

  19. Dynamics and stability of rigid rotors levitated by passive cylinder-magnet bearings and driven/supported axially by pointwise contact clutch

    NASA Astrophysics Data System (ADS)

    Andersen, Søren B.; Enemark, Søren; Santos, Ilmar F.

    2013-12-01

    A stable rotor—supported laterally by passive magnetic bearings and longitudinally by magnetic forces and a clutch—loses suddenly its contact to the clutch and executes abruptly longitudinal movements away from its original equilibrium position as a result of small increases in angular velocity. Such an abrupt unstable behaviour and its reasons are thoroughly theoretically as well as experimentally investigated in this work. In this context, this paper gives theoretical as well as experimental contributions to the problem of two dimensional passive magnetic levitation and one dimensional pointwise contact stability dictated by mechanical-magnetic interaction. Load capacity and stiffness of passive multicylinder magnetic bearings (MCMB) are thoroughly investigated using two theoretical approaches followed by experimental validation. The contact dynamics between the clutch and the rotor supported by MCMB using several configurations of magnet distribution are described based on an accurate nonlinear model able to reliably reproduce the rotor-bearing dynamic behaviour. Such investigations lead to: (a) clear physical explanation about the reasons for the rotor's unstable behaviour, losing its contact to the clutch and (b) an accurate prediction of the threshold of stability based on the nonlinear rotor-bearing model, i.e. maximum angular velocity before the rotor misses its contact to the clutch as a function of rotor, bearing and clutch design parameters. passive cylinder-magnet bearings, imbalance ring with a screw, passive rotating cylinder-magnets, rotor, Pointwise contact clutch, and DC-motor. The rotor (4) is levitated in the two horseshoe-shaped bearing houses (1) which contain several cylinder-magnets arranged in a circular pattern. These permanent magnets form a magnetic field around the rotor which repels similar cylinder-magnets (3) embedded in the rotor, thereby counteracting the gravity forces. As the shape of the magnetic field generated by the

  20. NONLINEAR FORCE-FREE FIELD EXTRAPOLATION OF A CORONAL MAGNETIC FLUX ROPE SUPPORTING A LARGE-SCALE SOLAR FILAMENT FROM A PHOTOSPHERIC VECTOR MAGNETOGRAM

    SciTech Connect

    Jiang, Chaowei; Wu, S. T.; Hu, Qiang; Feng, Xueshang E-mail: wus@uah.edu E-mail: fengx@spaceweather.ac.cn

    2014-05-10

    Solar filaments are commonly thought to be supported in magnetic dips, in particular, in those of magnetic flux ropes (FRs). In this Letter, based on the observed photospheric vector magnetogram, we implement a nonlinear force-free field (NLFFF) extrapolation of a coronal magnetic FR that supports a large-scale intermediate filament between an active region and a weak polarity region. This result is a first, in the sense that current NLFFF extrapolations including the presence of FRs are limited to relatively small-scale filaments that are close to sunspots and along main polarity inversion lines (PILs) with strong transverse field and magnetic shear, and the existence of an FR is usually predictable. In contrast, the present filament lies along the weak-field region (photospheric field strength ≲ 100 G), where the PIL is very fragmented due to small parasitic polarities on both sides of the PIL and the transverse field has a low signal-to-noise ratio. Thus, extrapolating a large-scale FR in such a case represents a far more difficult challenge. We demonstrate that our CESE-MHD-NLFFF code is sufficient for the challenge. The numerically reproduced magnetic dips of the extrapolated FR match observations of the filament and its barbs very well, which strongly supports the FR-dip model for filaments. The filament is stably sustained because the FR is weakly twisted and strongly confined by the overlying closed arcades.

  1. Nonlinear Force-free Field Extrapolation of a Coronal Magnetic Flux Rope Supporting a Large-scale Solar Filament from a Photospheric Vector Magnetogram

    NASA Astrophysics Data System (ADS)

    Jiang, Chaowei; Wu, S. T.; Feng, Xueshang; Hu, Qiang

    2014-05-01

    Solar filaments are commonly thought to be supported in magnetic dips, in particular, in those of magnetic flux ropes (FRs). In this Letter, based on the observed photospheric vector magnetogram, we implement a nonlinear force-free field (NLFFF) extrapolation of a coronal magnetic FR that supports a large-scale intermediate filament between an active region and a weak polarity region. This result is a first, in the sense that current NLFFF extrapolations including the presence of FRs are limited to relatively small-scale filaments that are close to sunspots and along main polarity inversion lines (PILs) with strong transverse field and magnetic shear, and the existence of an FR is usually predictable. In contrast, the present filament lies along the weak-field region (photospheric field strength <~ 100 G), where the PIL is very fragmented due to small parasitic polarities on both sides of the PIL and the transverse field has a low signal-to-noise ratio. Thus, extrapolating a large-scale FR in such a case represents a far more difficult challenge. We demonstrate that our CESE-MHD-NLFFF code is sufficient for the challenge. The numerically reproduced magnetic dips of the extrapolated FR match observations of the filament and its barbs very well, which strongly supports the FR-dip model for filaments. The filament is stably sustained because the FR is weakly twisted and strongly confined by the overlying closed arcades.

  2. Autism Spectrum Disorder: Does Neuroimaging Support the DSM-5 Proposal for a Symptom Dyad? A Systematic Review of Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging Studies

    ERIC Educational Resources Information Center

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

    2012-01-01

    A systematic review of 208 studies comprising functional magnetic resonance imaging and diffusion tensor imaging data in patients with "autism spectrum disorder" (ASD) was conducted, in order to determine whether these data support the forthcoming DSM-5 proposal of a social communication and behavioral symptom dyad. Studies consistently reported…

  3. Weight simulator

    NASA Technical Reports Server (NTRS)

    Howard, W. H.; Young, D. R.

    1972-01-01

    Device applies compressive force to bone to minimize loss of bone calcium during weightlessness or bedrest. Force is applied through weights, or hydraulic, pneumatic or electrically actuated devices. Device is lightweight and easy to maintain and operate.

  4. Sensitivity enhancement of an electrochemical immunosensor through the electrocatalysis of magnetic bead-supported non-enzymatic labels.

    PubMed

    Akter, Rashida; Kyun Rhee, Choong; Rahman, Md Aminur

    2014-04-15

    An ultrasensitive non-enzymatic electrochemical carcinoembryonic antigen (CEA) immunosensor was fabricated by the immobilization of a monoclonal CEA antibody (anti-CEA) on a protein A (PA) attached-gold nanoparticles (AuNPs)-deposited electrochemically prepared polydopamine film (e-PD/AuNPs). Magnetic beads (MB)-supported and CEA-conjugated multiple 3,3',5,5'-tetramethylbenzidine (TMB) was used as electrochemical labels. The detection was based on the measurements of the electrocatalyzed oxidation of ascorbic acid (AA) by the multiple TMB labels after competitive binding between MB/TMB-conjugated-CEA and free-CEA. The electrocatalyzed oxidation current of AA by TMB decreased with increasing concentration of the free-CEA as the amount of CEA/MB/TMB labels decreased at the immunosensor probe. The immunosensor surface was characterized using electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, quartz crystal microbalance, and scanning electron microscopy techniques. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used to monitor the electrocatalyzed response. The proposed immunosensor exhibited a wide linear dynamic range (1.0 pg/mL to 10.0 ng/mL), low detection limit (1.0±0.04 pg/mL), good selectivity, and long-time stability. It was successfully applied to various CEA spiked human serum samples for the detection of CEA. PMID:24292139

  5. Investigation of magnetically smart films applied to correct the surface profile of light weight X-ray optics in two directions

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoli; Yao, Youwei; Cao, Jian; Vaynman, Semyon; Graham, Michael E.; Liu, Tianchen; Ulmer, M. P.

    2015-09-01

    Our goal is to improve initially fabricated X-ray optics figures by applying a magnetic field to drive a magnetic smart material (MSM) coating on the non-reflecting side of the mirror. The consequent deformation of the surface should be three-dimensional. Here we will report on the results of working with a glass sample of 50x50x0.2 mm that has been coated with MSMs. The coated glass can be deformed in 3 dimensions and its surface profile was measured under our Zygo NewView white light interferometer (WLI). The driving magnetic field was produced via a pseudo-magnetic write head made up of two permanent magnet posts. The magnet posts were moved about the bottom of the glass sample with a 3-d computer controlled translation stage. The system allowed four degrees of freedom of motion, i.e., up and down, side to side, back and forth, and rotation of the posts (3.175 mm diameter) about the vertical axis to allow us to change the orientation of the magnetic field in the (horizontal) plane of the sample. We established a finite element analysis (FEA) model to predict deformations and compare with the observed results in order to guide the application of the magnetically controlled MSMs to improve the future X-ray optics figures.

  6. Marijuana and body weight.

    PubMed

    Sansone, Randy A; Sansone, Lori A

    2014-07-01

    Acute marijuana use is classically associated with snacking behavior (colloquially referred to as "the munchies"). In support of these acute appetite-enhancing effects, several authorities report that marijuana may increase body mass index in patients suffering from human immunodeficiency virus and cancer. However, for these medical conditions, while appetite may be stimulated, some studies indicate that weight gain is not always clinically meaningful. In addition, in a study of cancer patients in which weight gain did occur, it was less than the comparator drug (megestrol). However, data generally suggest that acute marijuana use stimulates appetite, and that marijuana use may stimulate appetite in low-weight individuals. As for large epidemiological studies in the general population, findings consistently indicate that users of marijuana tend to have lower body mass indices than nonusers. While paradoxical and somewhat perplexing, these findings may be explained by various study confounds, such as potential differences between acute versus chronic marijuana use; the tendency for marijuana use to be associated with other types of drug use; and/or the possible competition between food and drugs for the same reward sites in the brain. Likewise, perhaps the effects of marijuana are a function of initial weight status-i.e., maybe marijuana is a metabolic regulatory substance that increases body weight in low-weight individuals but not in normal-weight or overweight individuals. Only further research will clarify the complex relationships between marijuana and body weight. PMID:25337447

  7. Magnetically suspended reaction wheels

    NASA Technical Reports Server (NTRS)

    Sabnis, A. V.; Stocking, G. L.; Dendy, J. B.

    1975-01-01

    Magnetic suspensions offer several advantages over conventional bearings, arising because of the contactless nature of the load support. In application to spacecraft reaction wheels, the advantages are low drag torque, wearfree, unlubricated, vacuum-compatible operation, and unlimited life. By the provision of redundancy in the control electronics, single-point failures are eliminated. The rational for selection of a passive radial, active axial, dc magnetic suspension is presented, and the relative merits of 3-loop and single-loop magnetic suspensions are discussed. The design of a .678 N-m-sec (.5 ft-lb-sec) reaction wheel using the single loop magnetic suspension was developed; the design compares favorably with current ball bearing wheels in terms of weight and power.

  8. Cross-Axis Proportional Gains Used to Control Gyroscopic Effects in a Magnetic- Bearing-Supported Flywheel

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.; Kascak, Albert F.

    2001-01-01

    For magnetic-bearing-supported high-speed machines with significant gyroscopic effects, it is necessary to stabilize both forward and backward tilt whirling modes. Instability or the low damping of these modes can prevent the attainment of desired shaft speeds. Previous work elsewhere showed that cross-axis derivative gain in the magnetic bearing control law can improve the stability of the forward whirl mode, but it is commonly recognized that derivative gains amplify high-frequency noise and increase the required control effort. At the NASA Glenn Research Center, it has been shown previously that a simple cross-axis proportional gain can add stability (without adding noise) to either forward whirl or backward whirl, depending on the sign of the gain, but that such a gain destabilizes the other mode. It has been predicted by Glenn analysis that both modes can be stabilized by cross-axis proportional gains by utilizing the large-frequency separation of the two modes at speeds where the gyroscopic effects are significant. We use a modal controller that decouples the tilt and center-of-mass-translation modes. Only the tilt modes exhibit speed-dependent gyroscopic effects. The key to controlling them by the present method is to stabilize the backward whirl tilt mode with the appropriate sign of cross-axis proportional gain in the control law, but to include a low-pass filter on that gain term to restrict its effect only to the low-frequency backward-whirl mode. A second cross-axis term with the opposite sign and a high-pass filter stabilizes the forward whirl, which can have a frequency one or two orders of magnitude higher than the backward whirl, permitting very independent action of the two terms. Because the physical gyroscopic torques are proportional to the spinning speed of the shaft, it is convenient to gain-schedule the cross-axis control terms by making them proportional to shaft speed. This has the added benefit of avoiding a somewhat awkward zero

  9. Carbon supported Nano-Iron for environmental remediation: Transport observations using column tests, magnet resonance imaging and synchrotron tomography.

    NASA Astrophysics Data System (ADS)

    Busch, J.; Oswald, S. E.; Mackenzie, K.

    2012-04-01

    The use of nano-zerovalent iron (nZVI) for environmental remediation is a promising new technique for in situ remediation of contaminated groundwater. Due to its high surface area and high reactivity, nZVI is able to dechlorinate organic contaminants and render them harmless. Limited mobility, however, due to fast aggregation and sedimentation of nZVI, restricts the practical applicability for source and plume remediation. Carbo-Iron is a newly developed composite material consisting of activated carbon particles (d50 about 500 nm) that act as carrier for nZVI particles. Together with a polyanionic stabilizer (CMC) Carbo-Iron is able to form a stable injectable suspension. These particles are designed to combine the mobility of activated carbon and the reactivity of nZVI. Various methods were used to observe and describe transport properties, with a focus on column tests and tomographic methods: Column tests were performed in chromatography columns of 40 and 60 cm length, filled with sand grains or glass beads. Results indicate high mobility and breakthrough after addition of CMC, but changing transport properties at different pH and ionic strength. Magnet Resonance Imaging (MRI) and Synchrotron Imaging are technologies of growing interest in observing flow and transport in porous media. Even though both methods are based on different physical principles, both are sensible to iron loads in colloids and allow two- and three-dimensional reconstruction and visualization. Therefore both methods may principally be suitable for observing Carbo-Iron in porous media and might give information complementary to other experimental investigations. A suitable MRI method was developed using a medical MRI. The method based on T1 weighted measurement with short repetition time (TR = 7.0 ms) and echo time (TE = 2.95 ms) can detect different particle concentrations in a porous medium. The synchrotron tomography method used an energy rich (13 keV) parallel X-ray beam to collect

  10. Exercise support for therapy

    NASA Technical Reports Server (NTRS)

    Long, M. J.; Irick, S. C.

    1976-01-01

    Constant-value weight-relieving apparatus, which moves on rollers on overhead track, supports weight of walking, stooping, squatting, or standing patient with combination of multiple pulleys and spring clusters. Individually preselected support force is constant for all movements.

  11. Fabrication of Au nanoparticles supported on CoFe2O4 nanotubes by polyaniline assisted self-assembly strategy and their magnetically recoverable catalytic properties

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen; Jiang, Yanzhou; Chi, Maoqiang; Yang, Zezhou; Nie, Guangdi; Lu, Xiaofeng; Wang, Ce

    2016-02-01

    This article reports the fabrication of magnetically responsive Au nanoparticles supported on CoFe2O4 nanotubes through polyaniline (PANI) assisted self-assembly strategy which can be used as an efficient magnetically recoverable nanocatalyst. The central magnetic CoFe2O4 nanotubes possess a strong magnetic response under an externally magnetic field, enabling an easy and efficient separation from the reaction system for reuse. The thorn-like PANI layer on the surface of CoFe2O4 nanotubes provides large surface area for supporting Au nanocatalysts due to the electrostatic interactions. The as-prepared CoFe2O4/PANI/Au nanotube assemblies exhibit a high catalytic activity for the hydrogenation of 4-nitrophenol by sodium borohydride (NaBH4) at room temperature, with an apparent kinetic rate constant (Kapp) of about 7.8 × 10-3 s-1. Furthermore, the composite nanocatalyst shows a good recoverable property during the catalytic process. This work affords a reliable way in developing multifunctional nanocomposite for catalysis and other potential applications in many fields.

  12. Substitution of Ni for Fe in superconducting Fe0.98Te0.5Se0.5 depresses the normal-state conductivity but not the magnetic spectral weight

    NASA Astrophysics Data System (ADS)

    Wang, Jinghui; Zhong, Ruidan; Li, Shichao; Gan, Yuan; Xu, Zhijun; Zhang, Cheng; Ozaki, T.; Matsuda, M.; Zhao, Yang; Li, Qiang; Xu, Guangyong; Gu, Genda; Tranquada, J. M.; Birgeneau, R. J.; Wen, Jinsheng

    2015-01-01

    We have performed systematic resistivity and inelastic neutron scattering measurements on Fe0.98 -zNizTe0.5Se0.5 samples to study the impact of Ni substitution on the transport properties and the low-energy (≤12 meV) magnetic excitations. It is found that, with increasing Ni doping, both the conductivity and superconductivity are gradually suppressed; in contrast, the low-energy magnetic spectral weight changes little. Comparing with the impact of Co and Cu substitution, we find that the effects on conductivity and superconductivity for the same degree of substitution grow systematically as the atomic number of the substituent deviates from that of Fe. The impact of the substituents as scattering centers appears to be greater than any contribution to carrier concentration. The fact that low-energy magnetic spectral weight is not reduced by increased electron scattering indicates that the existence of antiferromagnetic correlations does not depend on electronic states close to the Fermi energy.

  13. Substitution of Ni for Fe in superconducting Fe0.98Te0.5Se0.5 depresses the normal-state conductivity but not the magnetic spectral weight

    DOE PAGESBeta

    Wang, Jinghui; Zhong, Ruidan; Li, Shichao; Gan, Yuan; Xu, Zhijun; Zhang, Cheng; Ozaki, T.; Matsuda, M.; Zhao, Yang; Li, Qiang; et al

    2015-01-05

    We have performed systematic resistivity and inelastic neutron scattering measurements on Fe₀.₉₈₋zNizTe₀.₅Se₀.₅ samples to study the impact of Ni substitution on the transport properties and the low-energy (≤ 12 meV) magnetic excitations. It is found that, with increasing Ni doping, both the conductivity and superconductivity are gradually suppressed; in contrast, the low-energy magnetic spectral weight changes little. Comparing with the impact of Co and Cu substitution, we find that the effects on conductivity and superconductivity for the same degree of substitution grow systematically as the atomic number of the substituent deviates from that of Fe. The impact of the substituentsmore » as scattering centers appears to be greater than any contribution to carrier concentration. The fact that low-energy magnetic spectral weight is not reduced by increased electron scattering indicates that the existence of antiferromagnetic correlations does not depend on electronic states close to the Fermi energy.« less

  14. Quantitative estimation of the spin-wave features supported by a spin-torque-driven magnetic waveguide

    SciTech Connect

    Consolo, Giancarlo Currò, Carmela; Valenti, Giovanna

    2014-12-07

    The main features of the spin-waves excited at the threshold via spin-polarized currents in a one-dimensional normally-to-plane magnetized waveguide are quantitatively determined both analytically and numerically. In particular, the dependence of the threshold current, frequency, wavenumber, and decay length is investigated as a function of the size of the nanocontact area through which the electric current is injected. From the analytical viewpoint, such a goal has required to solve the linearized Landau-Lifshitz-Gilbert-Slonczewski equation together with boundary and matching conditions associated with the waveguide geometry. Owing to the complexity of the resulting transcendent system, particular solutions have been obtained in the cases of elongated and contracted nanocontacts. These results have been successfully compared with those arising from numerical integration of the abovementioned transcendent system and with micromagnetic simulations. This quantitative agreement has been achieved thanks to the model here considered which takes explicitly into account the diagonal demagnetizing factors of a rectangular prism as well as the dependence of the relaxation rate on the wavenumber. Our analysis confirmed that the spin-wave features supported by such a waveguide geometry are significantly different from the ones observed in classical two-dimensional nanocontact devices. Moreover, it has been proved that the characteristic parameters depend strongly on the material properties and on the modulus of external field, but they could be independent of the nanocontact length. Finally, it is shown that spin-transfer oscillators based on contracted nanocontacts have a better capability to transmit spin-waves over large distances.

  15. Dynamics of EEG Rhythms Support Distinct Visual Selection Mechanisms in Parietal Cortex: A Simultaneous Transcranial Magnetic Stimulation and EEG Study

    PubMed Central

    Spadone, Sara; Tosoni, Annalisa; Sestieri, Carlo; Romani, Gian Luca; Della Penna, Stefania; Corbetta, Maurizio

    2015-01-01

    Using repetitive transcranial magnetic stimulation (rTMS), we have recently shown a functional anatomical distinction in human parietal cortex between regions involved in maintaining attention to a location [ventral intraparietal sulcus (vIPS)] and a region involved in shifting attention between locations [medial superior parietal lobule (mSPL)]. In particular, while rTMS interference over vIPS impaired target discrimination at contralateral attended locations, interference over mSPL affected performance following shifts of attention regardless of the visual field (Capotosto et al., 2013). Here, using rTMS interference in conjunction with EEG recordings of brain rhythms during the presentation of cues that indicate to either shift or maintain spatial attention, we tested whether this functional anatomical segregation involves different mechanisms of rhythm synchronization. The transient inactivation of vIPS reduced the amplitude of the expected parieto-occipital low-α (8–10 Hz) desynchronization contralateral to the cued location. Conversely, the transient inactivation of mSPL, compared with vIPS, reduced the high-α (10–12 Hz) desynchronization induced by shifting attention into both visual fields. Furthermore, rTMS induced a frequency-specific delay of task-related modulation of brain rhythms. Specifically, rTMS over vIPS or mSPL during maintenance (stay cues) or shifting (shift cues) of spatial attention, respectively, caused a delay of α parieto-occipital desynchronization. Moreover, rTMS over vIPS during stay cues caused a delay of δ (2–4 Hz) frontocentral synchronization. These findings further support the anatomo-functional subdivision of the dorsal attention network in subsystems devoted to shifting or maintaining covert visuospatial attention and indicate that these mechanisms operate in different frequency channels linking frontal to parieto-occipital visual regions. PMID:25589765

  16. International shipment of light weight radioisotopic heater units (LWRHU) using the USA/9516/B(U)F Mound 1 kW shipping package in support of the 'Pluto Express' mission

    SciTech Connect

    Barklay, Chadwick D.; Merten, C. William

    1997-01-10

    Radioisotopes have provided heat that has been used to maintain specific operating environments within remote satellites and spacecraft. For the 'Pluto Express' mission the {sup 238}PuO{sub 2} fueled light weight radioisotopic heater unit (LWRHU) will be used within the spacecraft. Since the current plan for the 'Pluto Express' mission incorporates the use of a Russian launch platform for the spacecraft, the LWRHUs must be transported in an internationally certified shipping container. An internationally certified shipping package that is versatile enough to be reconfigured to transport the LWRHUs that will be required to support the 'Pluto Express' mission is the Mound USA/9516/B(U)F.

  17. The importance of community consultation and social support in adhering to an obesity reduction program: results from the Healthy Weights Initiative

    PubMed Central

    Lemstra, Mark; Rogers, Marla R

    2015-01-01

    Background Few community-based obesity reduction programs have been evaluated. After 153 community consultations, the City of Moose Jaw, SK, Canada, decided to initiate a free comprehensive program. The initiative included 71 letters of support from the Mayor, every family physician, cardiologist, and internist in the city, and every relevant community group including the Heart and Stroke Foundation, the Canadian Cancer Society, and the Public Health Agency of Canada. Objective To promote strong adherence while positively influencing a wide range of physical and mental health variables measured through objective assessment or validated surveys. Methods The only inclusion criterion was that the individuals must be obese adults (body mass index >30 kg/m2). Participants were requested to sign up with a “buddy” who was also obese and identify three family members or friends to sign a social support contract. During the initial 12 weeks, each individual received 60 group exercise sessions, 12 group cognitive behavioral therapy sessions, and 12 group dietary sessions with licensed professionals. During the second 12-week period, maintenance therapy included 12 group exercise sessions (24 weeks in total). Results To date, 243 people have been referred with 229 starting. Among those who started, 183 completed the program (79.9%), while 15 quit for medical reasons and 31 quit for personal reasons. Mean objective reductions included the following: 31.0 lbs of body fat, 3.9% body fat, 2.9 in from the waist, 2.3 in from the hip, blood cholesterol by 0.5 mmol/L, systolic blood pressure by 5.9 mmHg, and diastolic blood pressure by 3.2 mmHg (all P<0.000). There were no changes in blood sugar levels. There was also statistically significant differences in aerobic fitness, self-report health, quality of life measured by Short Form-36, and depressed mood measured by Beck Depression Inventory-II (all P<0.000). Independent risk factors for not completing the program were not

  18. Application of an Activated Carbon-Based Support for Magnetic Solid Phase Extraction Followed by Spectrophotometric Determination of Tartrazine in Commercial Beverages

    PubMed Central

    Rodríguez, José A.; Escamilla-Lara, Karen A.; Guevara-Lara, Alfredo; Miranda, Jose M.

    2015-01-01

    A method is presented for magnetic solid phase extraction of tartrazine from nonalcoholic beverages. The method involves the extraction and clean-up by activated carbon covered with magnetite dispersed in the sample, followed by the magnetic isolation and desorption of the analyte by basified methanol. The tartrazine eluted from the magnetic support was determined by spectrophotometry. Under optimal conditions, the linear range of the calibration curve ranges from 3 to 30 mg L−1, with a limit of detection of 1 mg L−1. The method was validated by comparing the results with those obtained by HPLC. A precision of <5.0% was obtained in all cases and no significant differences were observed (P < 0.05). PMID:25873965

  19. The Weight of Evidence Does Not Support the Listing of Styrene as “Reasonably Anticipated to be a Human Carcinogen” in NTP's Twelfth Report on Carcinogens

    PubMed Central

    Rhomberg, Lorenz R.; Goodman, Julie E.; Prueitt, Robyn L.

    2013-01-01

    Styrene was listed as “reasonably anticipated to be a human carcinogen” in the twelfth edition of the National Toxicology Program's Report on Carcinogens based on what we contend are erroneous findings of limited evidence of carcinogenicity in humans, sufficient evidence of carcinogenicity in experimental animals, and supporting mechanistic data. The epidemiology studies show no consistent increased incidence of, or mortality from, any type of cancer. In animal studies, increased incidence rates of mostly benign tumors have been observed only in certain strains of one species (mice) and at one tissue site (lung). The lack of concordance of tumor incidence and tumor type among animals (even within the same species) and humans indicates that there has been no particular cancer consistently observed among all available studies. The only plausible mechanism for styrene-induced carcinogenesis—a non-genotoxic mode of action that is specific to the mouse lung—is not relevant to humans. As a whole, the evidence does not support the characterization of styrene as “reasonably anticipated to be a human carcinogen,” and styrene should not be listed in the Report on Carcinogens. PMID:23335843

  20. Magnetic

    NASA Astrophysics Data System (ADS)

    Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.

    2015-06-01

    The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and magnetic data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.

  1. Constructing magnetic polyaniline/metal hybrid nanostructures using polyaniline/Fe{sub 3}O{sub 4} composite hollow spheres as supports

    SciTech Connect

    Kong Lirong; Lu Xiaofeng; Jin, E; Jiang Shan; Bian Xiujie; Zhang Wanjin; Wang Ce

    2009-08-15

    Polyaniline (PANI)/Fe{sub 3}O{sub 4} composite hollow spheres have been successfully synthesized in one step using sulfonated polystyrene (PS) spheres as templates. The magnetic PANI hollow spheres were used as supports for noble metal nanoparticles (NPs) such as Au and Pd. The morphology, composition and magnetic properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma (ICP) atomic spectra and vibrating sample magnetometer. The catalytic activity of magnetic PANI/Au composite shells on the oxidation of dopamine was investigated by cyclic voltammetry. The obtained results provide our product with a practical application for the detection of dopamine. On the other hand, the catalytic activity of magnetic PANI/Pd composite shells on the reduction of 4-nitroaniline was investigated by spectroscopic methods and compared with Pd/C catalyst which was already widely used in industrial production. - Graphical abstract: TEM image of PANI/Fe{sub 3}O{sub 4} hollow spheres which can be used as supports for a variety of catalysts such as noble metal nanoparticles. Based on the unique properties of polyaniline hollow spheres and Fe{sub 3}O{sub 4} NPs, we designed the synthesis of polyaniline/Fe{sub 3}O{sub 4} NPs composite hollow spheres as supports for catalysts such as noble metal NPs. As a result, the obtained composites exhibit enhanced catalytic activities and can be easily separated from reaction mixture by using an NdFeB permanent magnet.

  2. Using magnetic levitation to distinguish atomic-level differences in chemical composition of polymers, and to monitor chemical reactions on solid supports.

    PubMed

    Mirica, Katherine A; Phillips, Scott T; Shevkoplyas, Sergey S; Whitesides, George M

    2008-12-31

    This communication describes a density-based method that uses magnetic levitation for monitoring solid-supported reactions and for distinguishing differences in chemical composition of polymers. The method is simple, rapid, and inexpensive and is similar to thin-layer chromatography (TLC; for solution-phase chemistry) in its potential for monitoring reactions in solid-phase chemistry. The technique involves levitating a sample of beads (taken from a reaction mixture) in a cuvette containing a paramagnetic solution (e.g., GdCl(3) dissolved in H(2)O) positioned between two NdFeB magnets. The vertical position at which the beads levitate corresponds to the density of the beads and correlates with the progress of a chemical reaction on a solid support. The method is particularly useful for monitoring the kinetics of reactions occurring on polymer beads. PMID:19063630

  3. Autism spectrum disorder: does neuroimaging support the DSM-5 proposal for a symptom dyad? A systematic review of functional magnetic resonance imaging and diffusion tensor imaging studies.

    PubMed

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

    2012-07-01

    A systematic review of 208 studies comprising functional magnetic resonance imaging and diffusion tensor imaging data in patients with 'autism spectrum disorder' (ASD) was conducted, in order to determine whether these data support the forthcoming DSM-5 proposal of a social communication and behavioral symptom dyad. Studies consistently reported abnormal function and structure of fronto-temporal and limbic networks with social and pragmatic language deficits, of temporo-parieto-occipital networks with syntactic-semantic language deficits, and of fronto-striato-cerebellar networks with repetitive behaviors and restricted interests in ASD patients. Therefore, this review partially supports the DSM-5 proposal for the ASD dyad. PMID:21932156

  4. Scuba Weights

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Attitude Adjuster is a system for weight repositioning corresponding to a SCUBA diver's changing positions. Compact tubes on the diver's air tank permit controlled movement of lead balls within the Adjuster, automatically repositioning when the diver changes position. Manufactured by Think Tank Technologies, the system is light and small, reducing drag and energy requirements and contributing to lower air consumption. The Mid-Continent Technology Transfer Center helped the company with both technical and business information and arranged for the testing at Marshall Space Flight Center's Weightlessness Environmental Training Facility for astronauts.

  5. Structural and magnetic properties of FeMnx chains (x =1 -6 ) supported on Cu2N /Cu (100)

    NASA Astrophysics Data System (ADS)

    Choi, Deung-Jang; Robles, Roberto; Gauyacq, Jean-Pierre; Ternes, Markus; Loth, Sebastian; Lorente, Nicolás

    2016-08-01

    Heterogeneous atomic magnetic chains are built by atom manipulation on a Cu2N /Cu (100) substrate. Their magnetic properties are studied and rationalized by a combined scanning tunneling microscopy (STM) and density functional theory (DFT) work completed by model Hamiltonian studies. The chains are built using Fe and Mn atoms ontop of the Cu atoms along the N rows of the Cu2N surface. Here, we present results for FeMnx chains (x =1 -6 ) emphasizing the evolution of the geometrical, electronic, and magnetic properties with chain size. By fitting our results to a Heisenberg Hamiltonian we have studied the exchange-coupling matrix elements J for different chains. For the shorter chains, x ≤2 , we have included spin-orbit effects in the DFT calculations, extracting the magnetic anisotropy energy. Our results are also fitted to a simple anisotropic spin Hamiltonian and we have extracted values for the longitudinal-anisotropy D and transversal-anisotropy E constants. These parameters together with the values for J allow us to compute the magnetic excitation energies of the system and to compare them with the experimental data.

  6. Technical analyses and related planning assistance in support of DOE's superconducting magnetic energy storage program. Final report

    SciTech Connect

    Hoenig, M.; Graneau, P.

    1983-03-15

    Various problems are assessed that will be encountered in the design of large superconducting magnetic energy storage (SMES) systems. Then a scoping study on design requirements for a 10,000 MWh SMES system is reported. Basic system requirements are defined, followed by a comparison of two basic coil concepts. (LEW)

  7. Bioinorganic magnetic core-shell nanocomposites carrying antiarthritic agents: intercalation of ibuprofen and glucuronic acid into Mg-Al-layered double hydroxides supported on magnesium ferrite.

    PubMed

    Ay, Ahmet Nedim; Zümreoglu-Karan, Birgül; Temel, Abidin; Rives, Vicente

    2009-09-21

    This paper describes the synthesis and characterization of a composite constituted by an antiarthritic agent (AA) intercalated into a layered double hydroxide (LDH) supported on magnesium ferrite. Core-shell nanocomposites were prepared by depositing Mg-Al-NO(3)-LDH on a MgFe(2)O(4) core prepared by calcination of a nonstoichiometric Mg-Fe-CO(3)-LDH. Intercalation of ibuprofen and glucuronate anions was performed by ion-exchange with nitrate ions. The structural characteristics of the obtained products were investigated by powder X-ray diffraction, element chemical analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Morphologies of the nanocomposite particles were examined by scanning electron microscopy and transmission electron microscopy. The products were shown to intercalate substantial amounts of AA with enhanced thermal stabilities. Room-temperature magnetic measurements by vibrating sample magnetometry revealed that the products show soft ferromagnetic properties suitable for potential utilization in magnetic arthritis therapy. PMID:19691269

  8. International shipment of light weight radioisotopic heater units (LWRHU) using the USA/9516/B(U)F Mound 1 kW shipping package in support of the {open_quotes}Pluto Express{close_quotes} mission

    SciTech Connect

    Barklay, C.D.; Merten, C.W.

    1997-01-01

    Radioisotopes have provided heat that has been used to maintain specific operating environments within remote satellites and spacecraft. For the {open_quotes}Pluto Express{close_quotes} mission the {sup 238}PuO{sub 2} fueled light weight radioisotopic heater unit (LWRHU) will be used within the spacecraft. Since the current plan for the {open_quotes}Pluto Express{close_quotes} mission incorporates the use of a Russian launch platform for the spacecraft, the LWRHUs must be transported in an internationally certified shipping container. An internationally certified shipping package that is versatile enough to be reconfigured to transport the LWRHUs that will be required to support the {open_quotes}Pluto Express{close_quotes} mission is the Mound USA/9516/B(U)F. {copyright} {ital 1997 American Institute of Physics.}

  9. Rapid weight loss

    MedlinePlus

    ... loss-rapid weight loss; Overweight-rapid weight loss; Obesity-rapid weight loss; Diet-rapid weight loss ... for people who have health problems because of obesity. For these people, losing a lot of weight ...

  10. Pregnancy Weight Gain Calculator

    MedlinePlus

    ... Newsroom Dietary Guidelines Communicator’s Guide Pregnancy Weight Gain Calculator You are here Home / Online Tools Pregnancy Weight Gain Calculator Print Share Pregnancy Weight Gain Calculator Pregnancy Weight Gain Calculator Pregnancy Weight Gain Intro ...

  11. Graphene supported silver@silver chloride & ferroferric oxide hybrid, a magnetically separable photocatalyst with high performance under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Zhong, Suting; Jiang, Wei; Han, Mei; Liu, Gongzong; Zhang, Na; Lu, Yue

    2015-08-01

    A stable magnetic separable plasmonic photocatalyst was successfully fabricated by grafting silver@silver chloride (Ag@AgCl) and ferroferric oxide (Fe3O4) nanoparticles on graphene sheets. The composite exhibited high activity degrading methylene blue (MB) and rhodamine B (RB) under visible light irradiation: decomposition 97.4% of MB in 100 min and 97.9% of RB in 120 min. The enhanced photocatalytic activities can be attributed to synergistic effect between Ag@AgCl and graphene: the effective charge transfer from Ag@AgCl to graphene thus promotes the separation of electron-hole pairs. Moreover, the excellent magnetic property gives a more convenient way to recycle the photocatalysts.

  12. Physiological adaptations to weight loss and factors favouring weight regain

    PubMed Central

    Greenway, F L

    2015-01-01

    Obesity is a major global health problem and predisposes individuals to several comorbidities that can affect life expectancy. Interventions based on lifestyle modification (for example, improved diet and exercise) are integral components in the management of obesity. However, although weight loss can be achieved through dietary restriction and/or increased physical activity, over the long term many individuals regain weight. The aim of this article is to review the research into the processes and mechanisms that underpin weight regain after weight loss and comment on future strategies to address them. Maintenance of body weight is regulated by the interaction of a number of processes, encompassing homoeostatic, environmental and behavioural factors. In homoeostatic regulation, the hypothalamus has a central role in integrating signals regarding food intake, energy balance and body weight, while an ‘obesogenic' environment and behavioural patterns exert effects on the amount and type of food intake and physical activity. The roles of other environmental factors are also now being considered, including sleep debt and iatrogenic effects of medications, many of which warrant further investigation. Unfortunately, physiological adaptations to weight loss favour weight regain. These changes include perturbations in the levels of circulating appetite-related hormones and energy homoeostasis, in addition to alterations in nutrient metabolism and subjective appetite. To maintain weight loss, individuals must adhere to behaviours that counteract physiological adaptations and other factors favouring weight regain. It is difficult to overcome physiology with behaviour. Weight loss medications and surgery change the physiology of body weight regulation and are the best chance for long-term success. An increased understanding of the physiology of weight loss and regain will underpin the development of future strategies to support overweight and obese individuals in their

  13. Physiological adaptations to weight loss and factors favouring weight regain.

    PubMed

    Greenway, F L

    2015-08-01

    Obesity is a major global health problem and predisposes individuals to several comorbidities that can affect life expectancy. Interventions based on lifestyle modification (for example, improved diet and exercise) are integral components in the management of obesity. However, although weight loss can be achieved through dietary restriction and/or increased physical activity, over the long term many individuals regain weight. The aim of this article is to review the research into the processes and mechanisms that underpin weight regain after weight loss and comment on future strategies to address them. Maintenance of body weight is regulated by the interaction of a number of processes, encompassing homoeostatic, environmental and behavioural factors. In homoeostatic regulation, the hypothalamus has a central role in integrating signals regarding food intake, energy balance and body weight, while an 'obesogenic' environment and behavioural patterns exert effects on the amount and type of food intake and physical activity. The roles of other environmental factors are also now being considered, including sleep debt and iatrogenic effects of medications, many of which warrant further investigation. Unfortunately, physiological adaptations to weight loss favour weight regain. These changes include perturbations in the levels of circulating appetite-related hormones and energy homoeostasis, in addition to alterations in nutrient metabolism and subjective appetite. To maintain weight loss, individuals must adhere to behaviours that counteract physiological adaptations and other factors favouring weight regain. It is difficult to overcome physiology with behaviour. Weight loss medications and surgery change the physiology of body weight regulation and are the best chance for long-term success. An increased understanding of the physiology of weight loss and regain will underpin the development of future strategies to support overweight and obese individuals in their efforts

  14. Supporting your child with weight loss

    MedlinePlus

    ... they are more likely to eat it. Homemade meals are often healthier than fast food or prepared foods. They can also save ... new to cooking, with a little practice, homemade meals can taste better than fast food. Take your children food shopping so they ...

  15. Pathologic Validation of a Model Based on Diffusion-Weighted Imaging and Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Tumor Delineation in the Prostate Peripheral Zone

    SciTech Connect

    Groenendaal, Greetje; Borren, Alie; Moman, Maaike R.; Monninkhof, Evelyn; Diest, Paul J. van; Philippens, Marielle E.P.; Vulpen, Marco van; Heide, Uulke A. van der

    2012-03-01

    Purpose: For focal boost strategies in the prostate, the robustness of magnetic resonance imaging-based tumor delineations needs to be improved. To this end we developed a statistical model that predicts tumor presence on a voxel level (2.5 Multiplication-Sign 2.5 Multiplication-Sign 2.5 mm3) inside the peripheral zone. Furthermore, we show how this model can be used to derive a valuable input for radiotherapy treatment planning. Methods and Materials: The model was created on 87 radiotherapy patients. For the validation of the voxelwise performance of the model, an independent group of 12 prostatectomy patients was used. After model validation, the model was stratified to create three different risk levels for tumor presence: gross tumor volume (GTV), high-risk clinical target volume (CTV), and low-risk CTV. Results: The model gave an area under the receiver operating characteristic curve of 0.70 for the prediction of tumor presence in the prostatectomy group. When the registration error between magnetic resonance images and pathologic delineation was taken into account, the area under the curve further improved to 0.89. We propose that model outcome values with a high positive predictive value can be used to define the GTV. Model outcome values with a high negative predictive value can be used to define low-risk CTV regions. The intermediate outcome values can be used to define a high-risk CTV. Conclusions: We developed a logistic regression with a high diagnostic performance for voxelwise prediction of tumor presence. The model output can be used to define different risk levels for tumor presence, which in turn could serve as an input for dose planning. In this way the robustness of tumor delineations for focal boost therapy can be greatly improved.

  16. Utilizing the adaptive polyoxometalate [As2W19O67(H2O)](14-) to support a polynuclear lanthanoid-based single-molecule magnet.

    PubMed

    Ritchie, Chris; Speldrich, Manfred; Gable, Robert W; Sorace, Lorenzo; Kögerler, Paul; Boskovic, Colette

    2011-08-01

    Five members of a new family of polyoxometalate (POM)-ligated tetranuclear rare earth metal complexes have been synthesized and characterized. These compounds have the general formula (HDABCO)(8)H(5)Li(8)[Ln(4)As(5)W(40)O(144)(H(2)O)(10)(gly)(2)]·25H(2)O [Ln = Gd (1), Tb (2), Dy (3), Ho (4) and Y = (5), HDABCO = monoprotonated 1,4-diazabicyclooctane, gly = glycine] and were synthesized from the preformed POM precursor [As(2)W(19)O(67)(H(2)O)](14-). The structure is comprised of two {As(2)W(19)O(68)} building blocks linked by a unit containing four rare earth ions and two additional tungsten centers, with the two glycine ligands playing a key bridging role. Two crystallographically distinct rare earth ions are present in each complex, both of which possess axially compressed, approximate square antiprismatic coordination geometry. The variable-temperature magnetic susceptibility profiles for 2-4 are dominated by population/depopulation of the M(J) sublevels of the relevant ground terms, and fitting of the data has afforded the ligand field parameters in each case, from which the energies of the M(J) sublevels can be calculated. Alternating current magnetic susceptibility data have revealed the onset of slow magnetic relaxation for 3, with the energy barrier to magnetization reversal determined to be 3.9(1) K. As for other lanthanoid complexes that display slow magnetic relaxation, this energy barrier is due to the splitting of the M(J) sublevels of the Dy(3+) ions such that the ground sublevel has a relatively large |M(J)| value, thereby affording Ising-type magnetic anisotropy. This complex is thus the first POM-supported polynuclear lanthanoid-based SMM. Simulation of the W-band EPR spectrum of 1 has afforded the spin Hamiltonian parameters for this species, while the X-band EPR spectrum of 3 indicates the presence of a non-negligible fourth-order transverse component of the anisotropy, which is responsible for the small effective energy barrier observed for 3

  17. Contribution of perfusion-weighted magnetic resonance imaging in the differentiation of meningiomas and other extra-axial tumors: case reports and literature review.

    PubMed

    Zimny, Anna; Sasiadek, Marek

    2011-07-01

    We present six cases of extra-axial lesions: three meningiomas [including one intraventricular and one cerebellopontine angle (CPA) meningioma], one dural metastasis, one CPA schwannoma and one choroid plexus papilloma which were chosen from a larger cohort of extra-axial tumors evaluated in our institution. Apart from conventional MR examinations, all the patients also underwent perfusion-weighted imaging (PWI) using dynamic susceptibility contrast method on a 1.5 T MR unit (contrast: 0.3 mmol/kg, rate 5 ml/s). Though the presented tumors showed very similar appearance on conventional MR images, they differed significantly in perfusion examinations. The article draws special attention to the usefulness of PWI in the differentiation of various extra-axial tumors and its contribution in reaching final correct diagnoses. Finding a dural lesion with low perfusion parameters strongly argues against the diagnosis of meningioma and should raise a suspicion of a dural metastasis. In cases of CPA tumors, a lesion with low relative cerebral blood volume values should be suspected to be schwannoma, allowing exclusion of meningioma to be made. In intraventricular tumors arising from choroid plexus, low perfusion parameters can exclude a diagnosis of meningioma. In our opinion, PWI as an easy and quick to perform functional technique should be incorporated into the MR protocol of all intracranial tumors including extra-axial neoplasms. PMID:21061142

  18. Efficacy of diffusion-weighted magnetic resonance imaging in follow-up patients treated with open partial cystectomy of liver hydatid cysts

    PubMed Central

    Karakas, Ekrem; Uzunköy, Ali; Karakas, Emel Yigit; Gundogan, Mehmet; Karakas, Omer; Boyaci, Fatıma Nurefsan; Seker, Ahmet; Ulas, Turgay; Cece, Hasan; Ozgonul, Abdullah; Cevik, Muazzez; Yucel, Yusuf

    2014-01-01

    Background and Objective: The aim of this study was to evaluate the efficacy of DWI in differentiation of patients with residual cavity and type 1 hydatid cyst (HC) in the liver. Methods: 32 patients were included. 12 of these patients had type 1 HC and the remainders (n = 20) had postoperative residual cavities. In all patients, axial T2-weighted and DWI images were obtained. An apparent diffusion coefficient (ADC) map of the images was automatically generated and the ADC values were measured on this map for all patients. Mann-Whitney U test was used for comparison of continuous variables between two groups. Results: The mean diameters of type 1 hydatid cyst and residual cavity groups were 83.42 mm, 49.30 mm, respectively (P = 0.001). There were no significant differences in gender and age between the groups (both P > 0.05). The mean ADC values of type 1 hydatid cyst and residual cavity groups were 2.58 ± 0.13 × 10-3 s/mm2, 2.58 ± 0.16 × 10-3 s/mm2, respectively (P = 0.953). Conclusion: DWI might not be suitable to differentiate the postoperative residual cavity from the type 1 hydatid cyst in the liver due to similarity of ADC values between postoperative residual cavity and type 1 hydatid cyst. PMID:25664009

  19. Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners.

    PubMed

    Bonutti, F; Tecchio, M; Maieron, M; Trevisan, D; Negro, C; Calligaris, F

    2016-03-01

    The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures. PMID:25987585

  20. The relationship between multiple developmental difficulties in very low birth weight children at 3½ years of age and the need for learning support at 5 years of age.

    PubMed

    Verkerk, Gijs; Jeukens-Visser, Martine; van Wassenaer-Leemhuis, Aleid; Kok, Joke; Nollet, Frans

    2014-01-01

    This study investigated whether multiple developmental difficulties are more frequent in very low birth weight (VLBW) children than in those born full term. The association between multiple developmental difficulties assessed at 3½ years of age and educational provision for the child at 5½ years was also investigated, with 'educational provision' referring to the curriculum, school placement and the level of learning support. There were 143 VLBW children without cerebral palsy (CP) and 41 term-born peers assessed at 3½ years of age. The assessment included 6 measures of development: word comprehension, visual motor integration, visual perception, motor coordination, executive functioning and behaviour. Educational provision was determined at age 5½ years. A mildly abnormal score (score <1 standard deviation) was considered to indicate developmental difficulty. Scores from the six measures of development were analysed to determine the difficulty frequency and the presence of multiple difficulties (>1 difficulty score) in each child. This study showed that at 3½ years of age, the VLBW children had significantly more difficulty with motor coordination than their term-born peers. In addition, 27% of the VLBW children had multiple difficulties compared to 10% in the term-born group. Multiple logistic regression analyses showed that of the difficulties, impaired motor coordination was most strongly associated with the requirement for learning support two years later. Regression analyses showed that having multiple difficulties was significantly associated with the need for learning support (Odds Ratio of 3.4 (95% CI: 1.5-7.8). These results show that the presence of multiple difficulties in a VLBW child of preschool age, can impact the child's educational provision two years later. PMID:24246854

  1. Collective magnetic properties of cobalt nanocrystals self-assembled in a hexagonal network: Theoretical model supported by experiments

    NASA Astrophysics Data System (ADS)

    Russier, V.; Petit, C.; Legrand, J.; Pileni, M. P.

    2000-08-01

    Numerical calculations of magnetization curves versus applied field based on a simple model taking into account dipolar interactions were performed for cobalt nanocrystals deposited on a substrate and organized in a hexagonal network. A random distribution of the easy axes orientations of the nanocrystals is considered. The study is focused on the effect of the applied field orientation relative to the substrate surface. Two orientations were chosen: parallel and perpendicular to the surface. The corresponding hysteresis loops are compared to that of a volumic random distribution of nanocrystals at vanishing concentration. The calculation results are compared to experimental data for spherical cobalt nanocrystals coated by lauric acid (C12H25COO-). The particles are either dispersed in hexane (considered as randomly distributed) or deposited in a hexagonal network on a highly oriented pyrolithic graphite substrate. The changes in the magnetization curves with the applied field orientation on the one hand and when going from dispersed to deposited particles on the other hand were calculated and measured. Qualitative agreement is obtained.

  2. A finite element analysis of stress distribution in the bone, around the implant supporting a mandibular overdenture with ball/o ring and magnetic attachment.

    PubMed

    John, Jins; Rangarajan, V; Savadi, Ravindra C; Satheesh Kumar, K S; Satheesh Kumar, Preeti

    2012-03-01

    Today implant dentistry has made great inroads into the treatment modalities that are available in treating an edentulous patient. Popularity of a two implant retained overdenture has created a necessity to examine the various attachment systems being used and the stresses that are transmitted to the alveolar bone. Hence a Three dimensional Finite Element Analysis was done to analyze the stress distribution in the mandibular bone with implant-supported overdenture having Ball/O-ring and Magnet attachments of different diameters. A segment of the anterior region of the mandible was modeled with implant and the overdenture. Four different models were generated having Ball/O-Ring and Magnet Attachments. Forces of 10 N, 35 N and 70 N were applied from the horizontal, vertical and oblique directions respectively and the stress distribution studied. It was concluded that the greatest stress concentrations were seen at the crest of the cortical bone and could be reduced by using smaller sized attachments for implant supported-overdenture. PMID:23450217

  3. Monitoring Early Response to Anti-Angiogenic Therapy: Diffusion-Weighted Magnetic Resonance Imaging and Volume Measurements in Colon Carcinoma Xenografts

    PubMed Central

    Schneider, Moritz Jörg; Cyran, Clemens Christian; Nikolaou, Konstantin; Hirner, Heidrun; Reiser, Maximilian F.; Dietrich, Olaf

    2014-01-01

    Objectives To evaluate the use of diffusion-weighted MRI (DW-MRI) and volume measurements for early monitoring of antiangiogenic therapy in an experimental tumor model. Materials and Methods 23 athymic nude rats, bearing human colon carcinoma xenografts (HT-29) were examined before and after 6 days of treatment with regorafenib (n = 12) or placebo (n = 11) in a clinical 3-Tesla MRI. For DW-MRI, a single-shot EPI sequence with 9 b-values (10–800 s/mm2) was used. The apparent diffusion coefficient (ADC) was calculated voxelwise and its median value over a region of interest, covering the entire tumor, was defined as the tumor ADC. Tumor volume was determined using T2-weighted images. ADC and volume changes between first and second measurement were evaluated as classifiers by a receiver-operator-characteristic (ROC) analysis individually and combined using Fisher's linear discriminant analysis (FLDA). Results All ADCs and volumes are stated as median±standard deviation. Tumor ADC increased significantly in the therapy group (0.76±0.09×10−3 mm2/s to 0.90±0.12×10−3 mm2/s; p<0.001), with significantly higher changes of tumor ADC than in the control group (0.10±0.11×10−3 mm2/s vs. 0.03±0.09×10−3 mm2/s; p = 0.027). Tumor volume increased significantly in both groups (therapy: 347.8±449.1 to 405.3±823.6 mm3; p = 0.034; control: 219.7±79.5 to 443.7±141.5 mm3; p<0.001), however, the therapy group showed significantly reduced tumor growth (33.30±47.30% vs. 96.43±31.66%; p<0.001). Area under the curve and accuracy of the ADC-based ROC analysis were 0.773 and 78.3%; and for the volume change 0.886 and 82.6%. The FLDA approach yielded an AUC of 0.985 and an accuracy of 95.7%. Conclusions Regorafenib therapy significantly increased tumor ADC after 6 days of treatment and also significantly reduced tumor growth. However, ROC analyses using each parameter individually revealed a lack of accuracy in discriminating between therapy and control

  4. Analysis of Metabolism in Dormant Spores of Bacillus Species by 31P Nuclear Magnetic Resonance Analysis of Low-Molecular-Weight Compounds

    PubMed Central

    Ghosh, Sonali; Korza, George; Maciejewski, Mark

    2014-01-01

    This work was undertaken to obtain information on levels of metabolism in dormant spores of Bacillus species incubated for weeks at physiological temperatures. Spores of Bacillus megaterium and Bacillus subtilis strains were harvested shortly after release from sporangia and incubated under various conditions, and dormant spore metabolism was monitored by 31P nuclear magnetic resonance (NMR) analysis of molecules including 3-phosphoglyceric acid (3PGA) and ribonucleotides. Incubation for up to 30 days at 4, 37, or 50°C in water, at 37 or 50°C in buffer to raise the spore core pH from ∼ 6.3 to 7.8, or at 4°C in spent sporulation medium caused no significant changes in ribonucleotide or 3PGA levels. Stage I germinated spores of Bacillus megaterium that had slightly increased core water content and a core pH of 7.8 also did not degrade 3PGA and accumulated no ribonucleotides, including ATP, during incubation for 8 days at 37°C in buffered saline. In contrast, spores incubated for up to 30 days at 37 or 50°C in spent sporulation medium degraded significant amounts of 3PGA and accumulated ribonucleotides, indicative of RNA degradation, and these processes were increased in B. megaterium spores with a core pH of ∼7.8. However, no ATP was accumulated in these spores. These data indicate that spores of Bacillus species stored in water or buffer at low or high temperatures exhibited minimal, if any, metabolism of endogenous compounds, even when the spore core pH was 7.8 and core water content was increased somewhat. However, there was some metabolism in spores stored in spent sporulation medium. PMID:25548246

  5. Diffusion-Weighted Magnetic Resonance Imaging Characterization of White Matter Injury Produced by Axon-Sparing Demyelination and Severe Contusion Spinal Cord Injury in Rats.

    PubMed

    Talbott, Jason F; Nout-Lomas, Yvette S; Wendland, Michael F; Mukherjee, Pratik; Huie, J Russell; Hess, Christopher P; Mabray, Marc C; Bresnahan, Jacqueline C; Beattie, Michael S

    2016-05-15

    Alterations in magnetic resonance imaging (MRI)-derived measurements of water diffusion parallel (D∥) and perpendicular (D⊥) to white matter tracts have been specifically attributed to pathology of axons and myelin, respectively. We test the hypothesis that directional diffusion measurements can distinguish between axon-sparing chemical demyelination and severe contusion spinal cord white matter injury. Adult rats received either unilateral ethidium bromide (EB) microinjections (chemical demyelination) into the lateral funiculus of the spinal cord at C5 or were subjected to unilateral severe contusion spinal cord injury (SCI). Diffusion MRI metrics in the lateral funiculus were analyzed at early and late time-points following injury and correlated with histology. Early EB-demyelination resulted in a significant elevation in D⊥ and significant reduction in D∥ at the injury epicenter, with histological evidence of uniform axon preservation. Alterations in D⊥ and D∥ at the epicenter of early EB-demyelination were not significantly different from those observed with severe contusion at the epicenter, where histology demonstrated severe combined axonal and myelin injury. Diffusion abnormalities away from the injury epicenter were seen with contusion injury, but not with EB-demyelination. Chronic EB lesions underwent endogenous remyelination with normalization of diffusion metrics, whereas chronic contusion resulted in persistently altered diffusivities. In the early setting, directional diffusion measurements at the injury epicenter associated with chemical demyelination are indistinguishable from those seen with severe contusive SCI, despite dramatic pathologic differences between injury models. Caution is advised in interpretation of diffusion metrics with respect to specific white matter structural alterations. Diffusion analysis should not be limited to the epicenter of focal spinal lesions as alterations marginal to the epicenter are useful for

  6. Prepubescent Strength Training Gains Support.

    ERIC Educational Resources Information Center

    Duda, Marty

    1986-01-01

    Recent studies have stimulated greater support for prepubescent weight training. There seems to be general agreement that strength and weight training, when practiced under properly controlled conditions, is safe and efficacious for prepubescents. Weight lifting is not supported. Recommendations for weight training are made, and reservations are…

  7. Silent cerebral infarct after cardiac catheterization as detected by diffusion weighted Magnetic Resonance Imaging: a randomized comparison of radial and femoral arterial approaches

    PubMed Central

    Hamon, Michèle; Burzotta, Francesco; Oppenheim, Catherine; Morello, Rémy; Viader, Fausto; Hamon, Martial

    2007-01-01

    Background and objective Cerebral microembolism detected by transcranial Doppler (TCD) occurs systematically during cardiac catheterization, but its clinical relevance, remains unknown. Studies suggest that asymptomatic embolic cerebral infarction detectable by diffusion-weighted (DW) MRI might exist after percutaneous cardiac interventions with a frequency as high as 15 to 22% of cases. We have set up, for the first time, a prospective multicenter trial to assess the rate of silent cerebral infarction after cardiac catheterization and to compare the impact of the arterial access site, comparing radial and femoral access, on this phenomenon. Study design This prospective study will be performed in patients with severe aortic valve stenosis. To assess the occurrence of cerebral infarction, all patients will undergo cerebral DW-MRI and neurological assessment within 24 hours before, and 48 hours after cardiac catheterization and retrograde catheterization of the aortic valve. Randomization for the access site will be performed before coronary angiography. A subgroup will be monitored by transcranial power M-mode Doppler during cardiac catheterization to observe cerebral blood flow and track emboli. Neuropsychological tests will also be recorded in a subgroup of patients before and after the interventional procedures to assess the impact of silent brain injury on potential cognitive decline. The primary end-point of the study is a direct comparison of ischemic cerebral lesions as detected by serial cerebral DW-MRI between patients explored by radial access and patients explored by femoral access. Secondary end-points include comparison of neuropsychological test performance and number of microembolism signals observed in the two groups. Implications Using serial DW-MRI, silent cerebral infarction rate will be defined and the potential influence of vascular access site will be evaluated. Silent cerebral infarction might be a major concern during cardiac catheterization

  8. Waste receiving and processing drum weight measurement uncertainty review findings

    SciTech Connect

    LANE, M.P.

    1999-05-12

    The purpose of reviewing the weight scale operation at the WRAP facility was to determine the uncertainty associated with weight measurements. Weight measurement uncertainty is needed to support WRAP Nondestructive Examination (NDE) and Non-destructive Assay (NDA) analysis.

  9. Reduced Field-of-View Diffusion-Weighted Magnetic Resonance Imaging of the Pancreas: Comparison with Conventional Single-Shot Echo-Planar Imaging

    PubMed Central

    Kim, Hyungjin; Yoon, Jeong Hee; Jang, Jin-Young; Kim, Sun-Whe; Ryu, Ji Kon; Kannengiesser, Stephan; Han, Joon Koo; Choi, Byung Ihn

    2015-01-01

    Objective To investigate the image quality (IQ) and apparent diffusion coefficient (ADC) of reduced field-of-view (FOV) di-ffusion-weighted imaging (DWI) of pancreas in comparison with full FOV DWI. Materials and Methods In this retrospective study, 2 readers independently performed qualitative analysis of full FOV DWI (FOV, 38 × 38 cm; b-value, 0 and 500 s/mm2) and reduced FOV DWI (FOV, 28 × 8.5 cm; b-value, 0 and 400 s/mm2). Both procedures were conducted with a two-dimensional spatially selective radiofrequency excitation pulse, in 102 patients with benign or malignant pancreatic diseases (mean size, 27.5 ± 14.4 mm). The study parameters included 1) anatomic structure visualization, 2) lesion conspicuity, 3) artifacts, 4) IQ score, and 5) subjective clinical utility for confirming or excluding initially considered differential diagnosis on conventional imaging. Another reader performed quantitative ADC measurements of focal pancreatic lesions and parenchyma. Wilcoxon signed-rank test was used to compare qualitative scores and ADCs between DWI sequences. Mann Whitney U-test was used to compare ADCs between the lesions and parenchyma. Results On qualitative analysis, reduced FOV DWI showed better anatomic structure visualization (2.76 ± 0.79 at b = 0 s/mm2 and 2.81 ± 0.64 at b = 400 s/mm2), lesion conspicuity (3.11 ± 0.99 at b = 0 s/mm2 and 3.15 ± 0.79 at b = 400 s/mm2), IQ score (8.51 ± 2.05 at b = 0 s/mm2 and 8.79 ± 1.60 at b = 400 s/mm2), and higher clinical utility (3.41 ± 0.64), as compared to full FOV DWI (anatomic structure, 2.18 ± 0.59 at b = 0 s/mm2 and 2.56 ± 0.47 at b = 500 s/mm2; lesion conspicuity, 2.55 ± 1.07 at b = 0 s/mm2 and 2.89 ± 0.86 at b = 500 s/mm2; IQ score, 7.13 ± 1.83 at b = 0 s/mm2 and 8.17 ± 1.31 at b = 500 s/mm2; clinical utility, 3.14 ± 0.70) (p < 0.05). Artifacts were significantly improved on reduced FOV DWI (2.65 ± 0.68) at b = 0 s/mm2 (full FOV DWI, 2.41 ± 0.63) (p < 0.001). On quantitative analysis, there were

  10. Weighted triangulation adjustment

    USGS Publications Warehouse

    Anderson, Walter L.

    1969-01-01

    The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.

  11. Comparison of two fat-suppressed magnetic resonance imaging pulse sequences to standard t2-weighted images for brain parenchymal contrast and lesion detection in dogs with inflammatory intracranial disease.

    PubMed

    Young, Benjamin D; Mankin, Joseph M; Griffin, John F; Fosgate, Geoffrey T; Fowler, Jennifer L; Levine, Jonathan M

    2015-01-01

    T2-weighted (T2w) sequences are commonly relied upon in magnetic resonance imaging protocols for the detection of brain lesions in dogs. Previously, the effect of fluid suppression via fluid-attenuated inversion recovery (FLAIR) has been compared to T2-weighting with mixed results. Short tau inversion recovery (STIR) has been reported to increase the detection of some CNS lesions in people. The purpose of the current study was to evaluate the effect of fat suppression on brain parenchymal contrast resolution and lesion detection in dogs. We compared three sequences: T2w images, STIR, and T2w FLAIR with chemical fat suppression (T2-FLAIR-FS) in dogs with meningoencephalitis. Dogs with meningoencephalitis and dogs with idiopathic epilepsy were retrospectively identified and anonymized. Evaluators recorded the presence or absence of lesions within 12 predetermined brain regions on randomized sequences, viewing and scoring each sequence individually. Additionally, signal-to-noise ratios, contrast-to-noise ratios, and relative contrast (RC) were measured in a reference population. Short tau inversion recovery sequences had the highest RC between gray and white matter. While descriptively more lesions were identified by evaluators on T2-FLAIR-FS images, there was no statistical difference in the relative sensitivity of lesion detection between the sequences. Nor was there a statistical difference in false lesion detection within our reference population. Short tau inversion recovery may be favored for enhanced anatomic contrast depiction in brain imaging. No benefit of the inclusion of a fat-suppressed T2-FLAIR sequence was found. PMID:25395066

  12. Dechlorination Mechanism of 2,4-Dichlorophenol by Magnetic MWCNTs Supported Pd/Fe Nanohybrids: Rapid Adsorption, Gradual Dechlorination, and Desorption of Phenol.

    PubMed

    Xu, Jiang; Liu, Xue; Lowry, Gregory Victor; Cao, Zhen; Zhao, Heng; Zhou, John L; Xu, Xinhua

    2016-03-23

    2,4-dichlorophenol was effectively removed from water using magnetic Pd/Fe nanoparticles supported on multiwalled carbon nanotubes (MWCNTs). The adsorption kinetics, isotherms, and energy for 2,4-dichlorophenol and its partially (4-chlorophenol, 2-chlorophenol) and completely (phenol) dechlorinated products are presented and discussed. The adsorption capacity was 2,4-dichlorophenol > 4-chlorophenol > 2-chlorophenol > phenol for MWCNTs. MWCNTs-Fe3O4-Pd/Fe nanohybrids provided rapid adsorption, gradual dechlorination, and final desorption of phenol, which is attractive as a remediation technology. Over 82.7% of the phenol was desorbed and released to the aqueous phase after 72 h due to its low adsorption capacity, leaving the majority of active sites available on the surface of MWCNTs-Fe3O4-Pd/Fe. The nanohybrids maintained high activity in five consecutive in situ experiments, and they were retrievable using magnetic separation. MWCNTs-Fe3O4-Pd/Fe nanohybrids outperform unsupported Pd/Fe nanoparticles, which were difficult to retrieve, and were easily passivated and aggregated. PMID:26938876

  13. 'Doctor, how can I lose weight?'.

    PubMed

    Bright-See, E

    1983-11-01

    Millions of Canadians are trying to lose weight. According to the Metropolitan Life Insurance Company's recently released height and weight tables, some of them don't need to lose weight from a health standpoint. For those who would benefit from weight loss, a good program includes a balanced, low fat, high fiber diet; exercise; behavior modification and moral support. Few of the popular books and self-help groups offer all these essential components. PMID:21283478

  14. Emotion Regulation and Excess Weight: Impaired Affective Processing Characterized by Dysfunctional Insula Activation and Connectivity

    PubMed Central

    Mata, Fernanda; Martínez-Zalacaín, Ignacio; Cano, Marta; Contreras-Rodríguez, Oren; Fernández-Aranda, Fernando; Yucel, Murat; Soriano-Mas, Carles; Verdejo-García, Antonio

    2016-01-01

    Emotion-regulation strategies are understood to influence food intake. This study examined the neurophysiological underpinnings of negative emotion processing and emotion regulation in individuals with excess weight compared to normal-weight controls. Fifteen participants with excess-weight (body mass index >25) and sixteen normal-weight controls (body mass index 18–25) performed an emotion-regulation task during functional magnetic resonance imaging. Participants were exposed to 24 negative affective or neutral pictures that they were instructed to Observe (neutral pictures), Maintain (sustain the emotion elicited by negative pictures) or Regulate (down-regulate the emotion provoked by negative pictures through previously trained reappraisal techniques). When instructed to regulate negative emotions by means of cognitive reappraisal, participants with excess weight displayed persistently heightened activation in the right anterior insula. Decreased responsivity was also found in right anterior insula, the orbitofrontal cortex and cerebellum during negative emotion experience in participants with excess weight. Psycho-physiological interaction analyses showed that excess-weight participants had decreased negative functional coupling between the right anterior insula and the right dlPFC, and the bilateral dmPFC during cognitive reappraisal. Our findings support contentions that excess weight is linked to an abnormal pattern of neural activation and connectivity during the experience and regulation of negative emotions, with the insula playing a key role in these alterations. We posit that ineffective regulation of emotional states contributes to the acquisition and preservation of excess weight. PMID:27003840

  15. Breast cancer and distress resulting from Magnetic Resonance Imaging (MRI): the impact of a psychological intervention of emotional and informative support.

    PubMed

    Caruso, A; Bongiorno, L; Vallini, L; Russo, P; Tomao, F; Grandinetti, M L

    2006-12-01

    The present study assesses the adaptation of a group of female patients with either manifest or suspected breast cancer who have undergone Magnetic Resonance Imaging (MRI) after receiving psychological support. Several studies in literature have reported the effectiveness of such support in reducing anti-oxidant and depression aspects related to MRI. Two random groups of patients, from the Service of Diagnostics Imaging of the Oncological Unit of the Regina Elena Institute of Rome, were enrolled. The experimental group (EG) received routine information together with extra psychological. The control group (CG) received only routine information. All the patients underwent a psychological evaluation, before (TO) and after (T1) the exam. The following evaluation instruments were used: the Crown Crisp Experimental Index (C.C. E.I.), the State-Trait Anxiety Inventory (S.T.A.I. Y1-Y2) and the Self Rating Depression Scale (S.D.S.) for TO and the State-Trait Anxiety Inventory (S.T.A.I. Y1 and the Self Rating Depression Scale (S.D.S.) for T1. Results prior to the MRI exam (TO), show that the women receiving extra information and emotional support (EG) suffer considerably less anxiety and depression compared to the control group. Results after the MRI exam (T1), indicate that the way the exam is carried out is also relevant in reducing anxiety. The level of anxiety, however, was significantly lower in the experimental group compared to the control. Depression levels, on the other hand, remained unaltered. Our results indicate that a psychological intervention aimed at providing more information and giving more emotional support helps patients adapt with a reduction of anxiety and depression. PMID:17310840

  16. A novel transient rotor current control scheme of a doubly-fed induction generator equipped with superconducting magnetic energy storage for voltage and frequency support

    NASA Astrophysics Data System (ADS)

    Shen, Yang-Wu; Ke, De-Ping; Sun, Yuan-Zhang; Daniel, Kirschen; Wang, Yi-Shen; Hu, Yuan-Chao

    2015-07-01

    A novel transient rotor current control scheme is proposed in this paper for a doubly-fed induction generator (DFIG) equipped with a superconducting magnetic energy storage (SMES) device to enhance its transient voltage and frequency support capacity during grid faults. The SMES connected to the DC-link capacitor of the DFIG is controlled to regulate the transient dc-link voltage so that the whole capacity of the grid side converter (GSC) is dedicated to injecting reactive power to the grid for the transient voltage support. However, the rotor-side converter (RSC) has different control tasks for different periods of the grid fault. Firstly, for Period I, the RSC injects the demagnetizing current to ensure the controllability of the rotor voltage. Then, since the dc stator flux degenerates rapidly in Period II, the required demagnetizing current is low in Period II and the RSC uses the spare capacity to additionally generate the reactive (priority) and active current so that the transient voltage capability is corroborated and the DFIG also positively responds to the system frequency dynamic at the earliest time. Finally, a small amount of demagnetizing current is provided after the fault clearance. Most of the RSC capacity is used to inject the active current to further support the frequency recovery of the system. Simulations are carried out on a simple power system with a wind farm. Comparisons with other commonly used control methods are performed to validate the proposed control method. Project supported by the National Natural Science Foundation of China (Grant No. 51307124) and the Major Program of the National Natural Science Foundation of China (Grant No. 51190105).

  17. Who succeeds in maintaining weight loss? A conceptual review of factors associated with weight loss maintenance and weight regain.

    PubMed

    Elfhag, K; Rössner, S

    2005-02-01

    Weight loss is difficult to achieve and maintaining the weight loss is an even greater challenge. The identification of factors associated with weight loss maintenance can enhance our understanding for the behaviours and prerequisites that are crucial in sustaining a lowered body weight. In this paper we have reviewed the literature on factors associated with weight loss maintenance and weight regain. We have used a definition of weight maintenance implying intentional weight loss that has subsequently been maintained for at least 6 months. According to our review, successful weight maintenance is associated with more initial weight loss, reaching a self-determined goal weight, having a physically active lifestyle, a regular meal rhythm including breakfast and healthier eating, control of over-eating and self-monitoring of behaviours. Weight maintenance is further associated with an internal motivation to lose weight, social support, better coping strategies and ability to handle life stress, self-efficacy, autonomy, assuming responsibility in life, and overall more psychological strength and stability. Factors that may pose a risk for weight regain include a history of weight cycling, disinhibited eating, binge eating, more hunger, eating in response to negative emotions and stress, and more passive reactions to problems. PMID:15655039

  18. Cervical Gross Tumor Volume Dose Predicts Local Control Using Magnetic Resonance Imaging/Diffusion-Weighted Imaging—Guided High-Dose-Rate and Positron Emission Tomography/Computed Tomography—Guided Intensity Modulated Radiation Therapy

    SciTech Connect

    Dyk, Pawel; Jiang, Naomi; Sun, Baozhou; DeWees, Todd A.; Fowler, Kathryn J.; Narra, Vamsi; Garcia-Ramirez, Jose L.; Schwarz, Julie K.; Grigsby, Perry W.

    2014-11-15

    Purpose: Magnetic resonance imaging/diffusion weighted-imaging (MRI/DWI)-guided high-dose-rate (HDR) brachytherapy and {sup 18}F-fluorodeoxyglucose (FDG) — positron emission tomography/computed tomography (PET/CT)-guided intensity modulated radiation therapy (IMRT) for the definitive treatment of cervical cancer is a novel treatment technique. The purpose of this study was to report our analysis of dose-volume parameters predicting gross tumor volume (GTV) control. Methods and Materials: We analyzed the records of 134 patients with International Federation of Gynecology and Obstetrics stages IB1-IVB cervical cancer treated with combined MRI-guided HDR and IMRT from July 2009 to July 2011. IMRT was targeted to the metabolic tumor volume and lymph nodes by use of FDG-PET/CT simulation. The GTV for each HDR fraction was delineated by use of T2-weighted or apparent diffusion coefficient maps from diffusion-weighted sequences. The D100, D90, and Dmean delivered to the GTV from HDR and IMRT were summed to EQD2. Results: One hundred twenty-five patients received all irradiation treatment as planned, and 9 did not complete treatment. All 134 patients are included in this analysis. Treatment failure in the cervix occurred in 24 patients (18.0%). Patients with cervix failures had a lower D100, D90, and Dmean than those who did not experience failure in the cervix. The respective doses to the GTV were 41, 58, and 136 Gy for failures compared with 67, 99, and 236 Gy for those who did not experience failure (P<.001). Probit analysis estimated the minimum D100, D90, and Dmean doses required for ≥90% local control to be 69, 98, and 260 Gy (P<.001). Conclusions: Total dose delivered to the GTV from combined MRI-guided HDR and PET/CT-guided IMRT is highly correlated with local tumor control. The findings can be directly applied in the clinic for dose adaptation to maximize local control.

  19. Effect of clothing weight on body weight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: In clinical settings, it is common to measure weight of clothed patients and estimate a correction for the weight of clothing, but we can find no papers in the medical literature regarding the variability in clothing weight with weather, season, and gender. Methods: Fifty adults (35 wom...

  20. Informed Test Component Weighting.

    ERIC Educational Resources Information Center

    Rudner, Lawrence M.

    2001-01-01

    Identifies and evaluates alternative methods for weighting tests. Presents formulas for composite reliability and validity as a function of component weights and suggests a rational process that identifies and considers trade-offs in determining weights. Discusses drawbacks to implicit weighting and explicit weighting and the difficulty of…

  1. Assessing Your Weight

    MedlinePlus

    ... Measure and Interpret Weight Status Adult Body Mass Index or BMI Body Mass Index (BMI) is a person's weight in kilograms divided ... finding your height and weight in this BMI Index Chart 1 . If your BMI is less than ...

  2. Atomic weights in gas analysis

    NASA Astrophysics Data System (ADS)

    van der Veen, Adriaan M. H.; Hafner, Katarina

    2014-02-01

    The publication of the standard atomic weights of 2009 by IUPAC raised the question of to what extent these changes affect the calculated composition of reference and calibration gas mixtures and the associated measurement uncertainty. The smallest uncertainties are attainable in the gravimetric gas mixture preparation, so the assessment was made for this technique. For the first time, the uncertainty contributions to the overall budget due to weighing, molecular weights, and composition of the parent gases are reported separately. The calculations show that even with the standard atomic weights of 2007, the uncertainty contribution due to the molecular weights can be of the same order as that due to weighing. The standard atomic weights of 2009 and 2011, when used under the same assumptions, increase the uncertainties of the amount-of-substance fractions of the abundant components from high-purity parent gases sometimes appreciably. Based on these calculations and the fact that the atomic weight intervals include sources that are unlikely to be generally relevant for measurements supporting trade, commerce, health and safety, there is a need to make a more in-depth analysis of the atomic weights used in calculations, and to reflect the knowledge about the isotopic composition of relevant materials in the value assignment and uncertainty calculation.

  3. Study on control method of running velocity for the permanent magnet-HTSC hybrid magnetically levitated conveyance system

    NASA Astrophysics Data System (ADS)

    Nishio, R.; Ikeda, M.; Sasaki, R.; Ohashi, S.

    2011-11-01

    We have developed the magnetically levitated carrying system. In this system, pinning force of high temperature bulk super conductor (HTSC) is used for the levitation and guidance. Four HTSCs are installed on the carrier. The magnetic rail is set on the ground, and flux from the magnetic rail is pinned by HTSCs. To increase levitation force, repulsive force of the permanent magnet is used. The hybrid levitation system is composed. The permanent magnet is installed under the load stage of the carrier. Repulsive force by the permanent magnet between the load stage on the carrier and the magnetic rail on the ground is used to support the load weight. Levitation and guidance one by pinning effect of the YBaCuO HTSC in the carrier is used to levitate the carrier body. The load stage is separated from the carrier flame and can move freely for vertical direction levitation. For the propulsion system, electromagnet is installed on the surface of the magnetic rail. In this paper, control method of running velocity of the carrier is studied. Propulsion force is given as follows; Air core copper coils are installed on the magnetic rail. Interaction between current of these coils and permanent magnets on the carrier generates propulsion force. Running velocity is controlled by current of the propulsion coils. It is also changed by position of the carrier and the load weight. From the results, stability of the propulsion system is given, and propulsion characteristics are improved.

  4. Body Weight Relationships in Early Marriage: Weight Relevance, Weight Comparisons, and Weight Talk

    PubMed Central

    Bove, Caron F.; Sobal, Jeffery

    2011-01-01

    This investigation uncovered processes underlying the dynamics of body weight and body image among individuals involved in nascent heterosexual marital relationships in Upstate New York. In-depth, semi-structured qualitative interviews conducted with 34 informants, 20 women and 14 men, just prior to marriage and again one year later were used to explore continuity and change in cognitive, affective, and behavioral factors relating to body weight and body image at the time of marriage, an important transition in the life course. Three major conceptual themes operated in the process of developing and enacting informants’ body weight relationships with their partner: weight relevance, weight comparisons, and weight talk. Weight relevance encompassed the changing significance of weight during early marriage and included attracting and capturing a mate, relaxing about weight, living healthily, and concentrating on weight. Weight comparisons between partners involved weight relativism, weight competition, weight envy, and weight role models. Weight talk employed pragmatic talk, active and passive reassurance, and complaining and critiquing criticism. Concepts emerging from this investigation may be useful in designing future studies of and approaches to managing body weight in adulthood. PMID:21864601

  5. Preoperative prediction of neurovascular bundle involvement of localized prostate cancer by combined T2 and diffusion-weighted imaging of magnetic resonance imaging, number of positive biopsy cores, and Gleason score.

    PubMed

    Naiki, Taku; Okamura, Takehiko; Nagata, Daisuke; Mori, Yuji; Kawai, Noriyasu; Ogawa, Kumiko; Akita, Hidetoshi; Hashimoto, Yoshihiro; Tozawa, Keiichi; Kohri, Kenjiro

    2011-01-01

    Because recovery of erectile function and avoidance of positive surgical margins are important but competing outcomes with prostate cancer therapy, the decision to preserve or resect a neurovascular bundle (NVB) during laparoscopic radical prostatectomy (LRP) should be firmly based on information concerning the presence and location of extracapsular extension. In the current retrospective study, the propriety of actual decisions was assessed using preoperative magnetic resonance imaging (MRI), combining T2-weighted imaging (T2WI) with diffusion-weighted imaging (DWI), the apparent diffusion coefficient (ADC), numbers of positive biopsy cores, tumor volume and the Gleason score. MRI before prostate biopsy was performed in 35 patients who underwent LRP for clinically localized prostate cancer. A single radiologist retrospectively assessed whether the tumor localization, capsular penetration, seminal vesicle invasion, NVB involvement, and MRI findings correlated with the postoperative histological results. With the postoperative specimens, 83 lesions demonstrated a Gleason score of 6 or more. Using T2WI with and without DWI and ADC, 39 and 27 of 54 lesions were correctly identified, respectively, the difference being significant. For cancers in the transitional zone, using a threshold Gleason score of 3 or greater, sensitivity was also significantly higher for T2+DWI+ADC than for T2WI alone. Of 35 patients, using all available clinical information (biopsy results including Gleason score, tumor location, percentage of positive biopsy cores, and the percentage of tumor-involved core tissue), we found that the preoperative and postoperative staging were concordant in 25 cases. There is no universal consensus for nerve-sparing LRP; therefore, we performed an additional analysis using simplified clinically defined selection criteria (PSA level >15ng/mL, cT2, less than two positive biopsy scores in the unilateral lobe and less than 30% tumor volume, and a Gleason score of 6

  6. Liver lobe-based magnetic resonance diffusion-weighted imaging using multiple b values in patients with hepatitis B-related liver cirrhosis: association with the liver disease severity according to the Child-Pugh class

    PubMed Central

    Tang, Hong-Jie; Zhou, Li; Zhang, Xiao-Ming; Liu, Jun; Chen, Tian-Wu; Zeng, Nan-Lin; Wang, Dan; Li, Jie; Huang, Yu-Cheng; Tang, Yu-Lian; Hu, Jiani

    2015-01-01

    OBJECTIVE: To determine the associations of liver lobe-based magnetic resonance diffusion-weighted imaging findings using multiple b values with the presence and Child-Pugh class of cirrhosis in patients with hepatitis B. METHODS: Seventy-four cirrhotic patients with hepatitis B and 25 healthy volunteers underwent diffusion-weighted imaging using b values of 0, 500, 800 and 1000 sec/mm2. The apparent diffusion coefficients of individual liver lobes for b(0,500), b(0,800) and b(0,1000) were derived from the signal intensity averaged across images obtained using b values of 0 and 500 sec/mm2, 0 and 800 sec/mm2, or 0 and 1000 sec/mm2, respectively, and were statistically analyzed to evaluate cirrhosis. RESULTS: The apparent diffusion coefficients for b(0,500), b(0,800) and b(0,1000) inversely correlated with the Child-Pugh class in the left lateral liver lobe, the left medial liver lobe, the right liver lobe and the caudate lobe (r=–0.35 to –0.60, all p<0.05), except for the apparent diffusion coefficient for b(0,1000) in the left medial liver lobe (r=–0.17, p>0.05). Among these parameters, the apparent diffusion coefficient for b(0,500) in the left lateral liver lobe best differentiated normal from cirrhotic liver, with an area under the receiver operating characteristic curve of 0.989. The apparent diffusion coefficient for b(0,800) in the right liver lobe best distinguished Child-Pugh class A from B–C and A–B from C, with areas under the receiver operating characteristic curve of 0.732 and 0.747, respectively. CONCLUSION: Liver lobe-based apparent diffusion coefficients for b(0,500) and b(0,800) appear to be associated with the presence and Child-Pugh class of liver cirrhosis. PMID:26222818

  7. Effect of biological characteristics of different types of uterine fibroids, as assessed with T2-weighted magnetic resonance imaging, on ultrasound-guided high-intensity focused ultrasound ablation.

    PubMed

    Zhao, Wen-Peng; Chen, Jin-Yun; Chen, Wen-Zhi

    2015-02-01

    The aims of this study were to assess the effects of the biological characteristics of different types of uterine fibroids, as assessed with T2-weighted magnetic resonance imaging (MRI), on ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation. Thirty-five patients with 39 symptomatic uterine fibroids who underwent myomectomy or hysterectomy were enrolled. Before surgery, the uterine fibroids were subdivided into hypo-intense, iso-intense, heterogeneous hyper-intense and homogeneous hyper-intense categories based on signal intensity on T2-weighted MRI. Tissue density and moisture content were determined in post-operative samples and normal uterine tissue, the isolated uterine fibroids were subjected to USgHIFU, and the extent of ablation was measured using triphenyltetrazolium chloride. Hematoxylin and eosin staining and sirius red staining were undertaken to investigate the organizational structure of the uterine fibroids. Estrogen and progesterone receptor expression was assayed via immunohistochemical staining. The mean diameter of uterine fibroids was 6.9 ± 2.8 cm. For all uterine fibroids, the average density and moisture content were 10.7 ± 0.7 mg/mL and 75.7 ± 2.4%, respectively; and for the homogeneous hyper-intense fibroids, 10.3 ± 0.5 mg/mL and 76.6 ± 2.3%. The latter subgroup had lower density and higher moisture content compared with the other subgroups. After USgHIFU treatment, the extent of ablation of the hyper-intense fibroids was 102.7 ± 42.1 mm(2), which was significantly less than those of the hypo-intense and heterogeneous hyper-intense fibroids. Hematoxylin and eosin staining and sirius red staining revealed that the homogeneous hyper-intense fibroids had sparse collagen fibers and abundant cells. Immunohistochemistry results revealed that estrogen and progesterone receptors were highly expressed in the homogeneous hyper-intense fibroids. This study revealed that lower density, higher moisture content, sparse collagen

  8. Rotating superconductor magnet for producing rotating lobed magnetic field lines

    DOEpatents

    Hilal, Sadek K.; Sampson, William B.; Leonard, Edward F.

    1978-01-01

    This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.

  9. Proven Weight Loss Methods

    MedlinePlus

    Fact Sheet Proven Weight Loss Methods What can weight loss do for you? Losing weight can improve your health in a number of ways. It can lower ... at www.hormone.org/Spanish . Proven Weight Loss Methods Fact Sheet www.hormone.org

  10. Weight Loss Surgery

    MedlinePlus

    Weight loss surgery helps people with extreme obesity to lose weight. It may be an option if you cannot lose weight through diet and exercise or have serious health problems caused by obesity. There are different types of weight loss surgery. They often limit the ...

  11. Forensic age estimation via 3-T magnetic resonance imaging of ossification of the proximal tibial and distal femoral epiphyses: Use of a T2-weighted fast spin-echo technique.

    PubMed

    Ekizoglu, Oguzhan; Hocaoglu, Elif; Inci, Ercan; Can, Ismail Ozgur; Aksoy, Sema; Kazimoglu, Cemal

    2016-03-01

    Radiation exposure during forensic age estimation is associated with ethical implications. It is important to prevent repetitive radiation exposure when conducting advanced ultrasonography (USG) and magnetic resonance imaging (MRI). The purpose of this study was to investigate the utility of 3.0-T MRI in determining the degree of ossification of the distal femoral and proximal tibial epiphyses in a group of Turkish population. We retrospectively evaluated coronal T2-weighted and turbo spin-echo sequences taken upon MRI of 503 patients (305 males, 198 females; age 10-30 years) using a five-stage method. Intra- and interobserver variations were very low. (Intraobserver reliability was κ=0.919 for the distal femoral epiphysis and κ=0.961 for the proximal tibial epiphysis, and interobserver reliability was κ=0.836 for the distal femoral epiphysis and κ=0.885 for the proximal tibial epiphysis.) Spearman's rank correlation analysis indicated a significant positive relationship between age and the extent of ossification of the distal femoral and proximal tibial epiphyses (p<0.001). Comparison of male and female data revealed significant between-gender differences in the ages at first attainment of stages 2, 3, and 4 ossifications of the distal femoral epiphysis and stage 1 and 4 ossifications of the proximal tibial epiphysis (p<0.05). The earliest ages at which ossification of stages 3, 4, and 5 was evident in the distal femoral epiphysis were 14, 17, and 22 years in males and 13, 16, and 21 years in females, respectively. Proximal tibial epiphysis of stages 3, 4, and 5 ossification was first noted at ages 14, 17, and 18 years in males and 13, 15, and 16 years in females, respectively. MRI of the distal femoral and proximal tibial epiphyses is an alternative, noninvasive, and reliable technique to estimate age. PMID:26797254

  12. Diagnosis of lateral pelvic lymph node metastasis of T1 lower rectal cancer using diffusion-weighted magnetic resonance imaging: A case report with lateral pelvic lymph node dissection of lower rectal cancer

    PubMed Central

    OGAWA, SHIMPEI; ITABASHI, MICHIO; HIROSAWA, TOMOICHIRO; HASHIMOTO, TAKUZO; BAMBA, YOSHIKO; OKAMOTO, TAKAHIRO

    2016-01-01

    The present study presented a 35-year-old female patient in whom fecal occult blood was detected in a medical check-up. Colonoscopy revealed a superficial elevated-type tumor with central depression in the lower rectum. The tumor was diagnosed as T1 deep invasive cancer. No swollen lymph nodes or distant metastasis were found on computed tomography or [18F]-fluorodeoxyglucose-positron emission tomography with computed tomography. However, a swollen right lateral pelvic lymph node (LPLN; short axis 4 mm) was revealed on magnetic resonance imaging (MRI). This lymph node exhibited high intensity on diffusion-weighted imaging (DWI), suggesting metastasis. Low anterior resection, regional lymph node dissection and right LPLN dissection (LPLD) were performed. Histological analysis revealed metastasis in the right LPLN, as suggested by the high DWI intensity. The indication for LPLD in the current Japanese guidelines is based on the tumor location and depth of invasion (≥T3), however, not on the status of LPLN metastasis in pre-operative evaluation. The present case was cT1, which is not included in this indication. DWI is sensitive for the diagnosis of lymph node metastasis of colorectal cancer, although inflammation-induced swelling of lymph nodes in advanced rectal cancer may cause a false-positive result, which is uncommon in T1 cases. Therefore, an LPLN with a high intensity DWI signal in T1 cases is likely to be metastasis-positive. Pre-operative DWI-MRI may be useful for identifying LPLN metastasis when planning the treatment strategy in these cases. The present study suggested reinvestigation of the indication for LPLD with inclusion of LPLN status on pre-operative imaging. PMID:27123286

  13. PREVENTING WEIGHT REGAIN AFTER WEIGHT LOSS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For most dieters, a regaining of lost weight is an all too common experience. Indeed, virtually all interventions for weight loss show limited or even poor long-term effectiveness. This sobering reality was reflected in a comprehensive review of nonsurgical treatments of obesity conducted by the Ins...

  14. Iron Oxide-Supported Copper Oxide Nanoparticles (Nanocat-Fe-CuO): Magnetically Recyclable Catalysts for the Synthesis of Pyrazole Derivatives, 4-Methoxyaniline, and Ullmann-type Condensation Reactions

    EPA Science Inventory

    An efficient and benign protocol is reported for the synthesis of 4-methoxyaniline, medicinally important pyrazole derivatives, and Ullmann-type condensation reaction using magnetically separable and reusable magnetite-supported copper (nanocat-Fe-CuO) nanoparticles under mild co...

  15. Financial Incentives and Weight Control

    PubMed Central

    Jeffery, Robert W.

    2012-01-01

    This paper reviews research studies evaluating the use of financial incentives to promote weight control conducted between 1972 and 2010. It provides an overview of behavioral theories pertaining to incentives and describes empirical studies evaluating specific aspects of incentives. Research on financial incentives and weight control has a history spanning more than 30 years. Early studies were guided by operant learning concepts from Psychology, while more recent studies have relied on economic theory. Both theoretical orientations argue that providing financial rewards for losing weight should motivate people to engage in behaviors that produce weight loss. Empirical research has strongly supported this idea. However, results vary widely due to differences in incentive size and schedule, as well as contextual factors. Thus, many important questions about the use of incentives have not yet been clearly answered. Weight-maintenance studies using financial incentives are particularly sparse, so that their long-term efficacy and thus, value in addressing the public health problem of obesity is unclear. Major obstacles to sustained applications of incentive in weight control are funding sources and acceptance by those who might benefit. PMID:22244800

  16. A support vector machine-based method to identify mild cognitive impairment with multi-level characteristics of magnetic resonance imaging.

    PubMed

    Long, Zhuqing; Jing, Bin; Yan, Huagang; Dong, Jianxin; Liu, Han; Mo, Xiao; Han, Ying; Li, Haiyun

    2016-09-01

    Mild cognitive impairment (MCI) represents a transitional state between normal aging and Alzheimer's disease (AD). Non-invasive diagnostic methods are desirable to identify MCI for early therapeutic interventions. In this study, we proposed a support vector machine (SVM)-based method to discriminate between MCI patients and normal controls (NCs) using multi-level characteristics of magnetic resonance imaging (MRI). This method adopted a radial basis function (RBF) as the kernel function, and a grid search method to optimize the two parameters of SVM. The calculated characteristics, i.e., the Hurst exponent (HE), amplitude of low-frequency fluctuations (ALFF), regional homogeneity (ReHo) and gray matter density (GMD), were adopted as the classification features. A leave-one-out cross-validation (LOOCV) was used to evaluate the classification performance of the method. Applying the proposed method to the experimental data from 29 MCI patients and 33 healthy subjects, we achieved a classification accuracy of up to 96.77%, with a sensitivity of 93.10% and a specificity of 100%, and the area under the curve (AUC) yielded up to 0.97. Furthermore, the most discriminative features for classification were found to predominantly involve default-mode regions, such as hippocampus (HIP), parahippocampal gyrus (PHG), posterior cingulate gyrus (PCG) and middle frontal gyrus (MFG), and subcortical regions such as lentiform nucleus (LN) and amygdala (AMYG). Therefore, our method is promising in distinguishing MCI patients from NCs and may be useful for the diagnosis of MCI. PMID:27343830

  17. Development of HTS Magnet for Rotating Gantry

    NASA Astrophysics Data System (ADS)

    Tasaki, Kenji; Koyanagi, Kei; Takayama, S. Shigeki; Ishii, Yusuke; Kurusu, Tsutomu; Amemiya, Naoyuki; Ogitsu, Toru; iwata, Yoshiyuki; Noda, Koji

    The effectiveness of heavy-ion radiotherapy for cancer treatment has been recognized by medical experts and the public. However, due to the large size of the equipment, this therapy has not been widely adopted. In particular, the rotating gantries used to irradiate patients with the heavy-ion beams from any direction may be as heavy as 600 tons in our estimation. By employing high-temperature superconducting (HTS) wires in these rotating gantries and increasing the magnetic field generated by the deflecting coils, the total weight of the rotating gantry can be reduced to around the weight of those used for proton radiotherapy. A project for developing an HTS deflecting magnet for heavy-ion radiotherapy has been underway since 2013, supported by the Japanese Ministry of Economy, Trade and Industry (METI) and the Japan Agency for Medical Research and Development (AMED). The aim of this project is to develop fundamental technologies for designing and fabricating HTS deflecting magnets, such as irregular magnetic field estimating techniques, design technology for HTS magnets, high-precision HTS coil winding technology, AC loss estimating techniques, and thermal runaway estimating techniques and to fabricate a small model of an HTS deflecting magnet and evaluate its performance. In this paper, the project's progress will be described.

  18. Weightings and water inflows during longwall working

    SciTech Connect

    Farmer, I.W.

    1996-12-01

    Weightings and water inflows into longwall workings often occur together, giving rise to discussions on their relative genesis. Case histories are introduced which indicate that most water inflows are associated with heavy weightings. Resultant large releases of energy can lead to extensive vertical fractures, which can drain water from aquifers or other sources, such as separation accumulations, onto the face. Effectively control of water inflows in these cases depends on face support and weighting control.

  19. On the interplay between geometrical structure and magnetic anisotropy: a relativistic density-functional study of mixed Pt-Co and Pt-Fe trimers and tetramers in the gas-phase and supported on graphene.

    PubMed

    Błoński, Piotr; Hafner, Jürgen

    2015-02-01

    The structural and magnetic properties of mixed Pt-Co and Pt-Fe trimers and tetramers in the gas-phase and supported on a free-standing graphene layer have been calculated using density-functional theory. The influence of the strong magnetic moments of the 3d atoms on the Pt atoms and the influence of the strong spin-orbit coupling contributed by the Pt atoms on the 3d atoms have been studied in detail. All mixed trimers form isocele triangles in the gas-phase. On a graphene layer the structure is influenced by the strong binding of the 3d atoms, leading to an asymmetric configuration for Pt-rich and more symmetric structures for 3d-rich clusters. The magnetic anisotropy energy defined as the energy difference for easy and hard magnetization directions varies between 5 and 13 meV/atom for the free trimers, but is strongly reduced to values between 0.7 and 6.6 meV/atom for the graphene-supported clusters. The saddle-point energy representing the barrier against magnetization reversal is on average 3 meV/atom for free trimers, it is reduced to 2 meV/atom for the more symmetric PtCo(Fe)(2) clusters, and to only about 0.3 meV/atom for the asymmetric Pt(2)Co(Fe) cluster on graphene. For the mixed tetramers the strong magnetism stabilizes a flat geometric structure, except for Pt(3)Co which forms a distorted trigonal pyramid. The geometry of the graphene-supported tetramers is very different due to the requirement of a good match to the substrate. Large magnetic anisotropy energies are found for free Pt(3)Co where the change of the magnetization direction also induces a transition from a high- to a low-moment magnetic isomer. For all other free tetramers the magnetic anisotropy energy ranges between 3 to 5 meV/atom only, it is further reduced to 0.4 to 3.8 meV/atom for the graphene-supported tetramers. The reduction is strongest for Pt(3)Fe/graphene because of the asymmetric structure of the adsorption complex. The barriers against magnetization reversal range between

  20. 40 CFR Appendix A to Subpart Pppp... - Determination of Weight Volatile Matter Content and Weight Solids Content of Reactive Adhesives

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... mate the edges. 9. Place the supported sandwich on a flat surface. 10. Place the weight on top of the.... Place the second support panel on top of the assembly to make a supported sandwich. Take care to...

  1. Gestational weight gain among Hispanic women.

    PubMed

    Sangi-Haghpeykar, Haleh; Lam, Kim; Raine, Susan P

    2014-01-01

    To describe gestational weight gain among Hispanic women and to examine psychological, social, and cultural contexts affecting weight gain. A total of 282 Hispanic women were surveyed post-partum before leaving the hospital. Women were queried about their prepregnancy weight and weight gained during pregnancy. Adequacy of gestational weight gain was based on guidelines set by the Institute of Medicine in 2009. Independent risk factors for excessive or insufficient weight gain were examined by logistic regression. Most women were unmarried (59 %), with a mean age of 28.4 ± 6.6 years and an average weight gain of 27.9 ± 13.3 lbs. Approximately 45 % of women had gained too much, 32 % too little, and only 24 % had an adequate amount of weight gain. The mean birth weight was 7.3, 7.9, and 6.8 lbs among the adequate, excessive, and insufficient weight gain groups. Among women who exercised before pregnancy, two-thirds continued to do so during pregnancy; the mean gestational weight gain of those who continued was lower than those who stopped (26.8 vs. 31.4 lbs, p = 0.04). Independent risk factors for excessive weight gain were being unmarried, U.S. born, higher prepregnancy body mass index, and having indifferent or negative views about weight gain. Independent risk factors for insufficient weight gain were low levels of support and late initiation of prenatal care. Depression, stress, and a woman's or her partner's happiness regarding pregnancy were unrelated to weight gain. The results of this study can be used by prenatal programs to identify Hispanic women at risk for excessive or insufficient gestational weight gain. PMID:23456347

  2. Weight-loss medications

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000346.htm Weight-loss medicines To use the sharing features on this page, please enable JavaScript. Several weight-loss medicines are available. Ask your health care provider ...

  3. Weight Loss & Acute Porphyria

    MedlinePlus

    ... Sale You are here Home Diet and Nutrition Weight loss & acute Porphyria Being overweight is a particular problem ... one of these diseases before they enter a weight-loss program. Also, they should not participate in a ...

  4. Losing weight after pregnancy

    MedlinePlus

    ... below the minimum number of calories you need. Breastfeeding If you are breastfeeding, you will want to lose weight slowly. Weight ... not affect your milk supply or your health. Breastfeeding makes your body burn calories. It helps you ...

  5. Weighted network modules

    NASA Astrophysics Data System (ADS)

    Farkas, Illés; Ábel, Dániel; Palla, Gergely; Vicsek, Tamás

    2007-06-01

    The inclusion of link weights into the analysis of network properties allows a deeper insight into the (often overlapping) modular structure of real-world webs. We introduce a clustering algorithm clique percolation method with weights (CPMw) for weighted networks based on the concept of percolating k-cliques with high enough intensity. The algorithm allows overlaps between the modules. First, we give detailed analytical and numerical results about the critical point of weighted k-clique percolation on (weighted) Erdos Rényi graphs. Then, for a scientist collaboration web and a stock correlation graph we compute three-link weight correlations and with the CPMw the weighted modules. After reshuffling link weights in both networks and computing the same quantities for the randomized control graphs as well, we show that groups of three or more strong links prefer to cluster together in both original graphs.

  6. Pregnancy and Healthy Weight

    MedlinePlus

    ... Division (HMD) of the National Academies of Sciences, Engineering, and Medicine released updated guidelines for weight gain ... Division (HMD) of the National Academies of Sciences, Engineering, and Medicine: Weight Gain During Pregnancy: Reexamining the ...

  7. Watching Your Weight.

    ERIC Educational Resources Information Center

    Clarke, Doug

    1993-01-01

    Describes an activity shared at an inservice teacher workshop and suitable for middle school in which students predict their ideal weight in kilograms based on tables giving ideal weights for given heights. (MDH)

  8. Effects of background electrolytes and ionic strength on enrichment of Cd(II) ions with magnetic graphene oxide-supported sulfanilic acid.

    PubMed

    Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; You, Shao-hong; Wang, Hui; Hu, Xi; Guo, Yi-ming; Tan, Xiao-fei; Guo, Fang-ying

    2014-12-01

    To elucidate the influence mechanisms of background electrolytes and ionic strength on Cd(II) removal, the adsorption of Cd(II) onto magnetic graphene oxide-supported sulfanilic acid (MGO-SA) in aqueous solutions containing different types and concentrations of background electrolytes was studied. The results indicate that Cd(II) adsorption was strongly dependent on pH and could be strongly affected by background electrolytes and ionic strength. The Cd(II) removal was decreased with the presence of background electrolyte cations (Na(+), K(+), Ca(2+), Mg(2+), Mn(2+), Zn(2+), and Ni(2+)), and the divalent cations exerted more obvious influences on the Cd(II) uptake than the monovalent cations at pH 6. Both Cl(-) and NO3(-) had negative effects on Cd(II) adsorption because they can form water-soluble metal-anion complexes with Cd(II) ions. The presence of 0.01molL(-1) Na3PO4 reduced the removal percentage of Cd(II) at pH<5 but extremely enhanced the Cd(II) removal when the pH>5. The Cd(II) adsorption was sensitive to changes in the concentration of NaCl, NaNO3, NaClO4, and Na3PO4. Besides, the adsorption isotherm of Cd(II) onto MGO-SA could be well described by the Freundlich model and was also influenced by the type of background electrolyte ions and the ionic strength. PMID:25238326

  9. The INTERPRET Decision-Support System version 3.0 for evaluation of Magnetic Resonance Spectroscopy data from human brain tumours and other abnormal brain masses

    PubMed Central

    2010-01-01

    Background Proton Magnetic Resonance (MR) Spectroscopy (MRS) is a widely available technique for those clinical centres equipped with MR scanners. Unlike the rest of MR-based techniques, MRS yields not images but spectra of metabolites in the tissues. In pathological situations, the MRS profile changes and this has been particularly described for brain tumours. However, radiologists are frequently not familiar to the interpretation of MRS data and for this reason, the usefulness of decision-support systems (DSS) in MRS data analysis has been explored. Results This work presents the INTERPRET DSS version 3.0, analysing the improvements made from its first release in 2002. Version 3.0 is aimed to be a program that 1st, can be easily used with any new case from any MR scanner manufacturer and 2nd, improves the initial analysis capabilities of the first version. The main improvements are an embedded database, user accounts, more diagnostic discrimination capabilities and the possibility to analyse data acquired under additional data acquisition conditions. Other improvements include a customisable graphical user interface (GUI). Most diagnostic problems included have been addressed through a pattern-recognition based approach, in which classifiers based on linear discriminant analysis (LDA) were trained and tested. Conclusions The INTERPRET DSS 3.0 allows radiologists, medical physicists, biochemists or, generally speaking, any person with a minimum knowledge of what an MR spectrum is, to enter their own SV raw data, acquired at 1.5 T, and to analyse them. The system is expected to help in the categorisation of MR Spectra from abnormal brain masses. PMID:21114820

  10. Magnetically levitated superconducting bearing

    SciTech Connect

    Weinberger, B.R.; Lynds, L. Jr.

    1993-10-26

    A magnetically levitated superconducting bearing includes a magnet mounted on a shaft that is rotatable around an axis of rotation and a Type II superconductor supported on a stator in proximity to the magnet. The superconductor is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet to produce an attractive force that levitates the magnet and supports a load on the shaft. The interaction between the superconductor and magnet also produces surface screening currents that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature. The bearing could also be constructed so the magnet is supported on the stator and the superconductor is mounted on the shaft. The bearing can be operated by cooling the superconductor to its superconducting state in the presence of a magnetic field. 6 figures.

  11. Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI

    PubMed Central

    Yoon, Haesung; Yoon, Dahye; Yun, Mijin; Choi, Ji Soo; Park, Vivian Youngjean; Kim, Eun-Kyung; Jeong, Joon; Koo, Ja Seung; Yoon, Jung Hyun; Moon, Hee Jung; Kim, Suhkmann; Kim, Min Jung

    2016-01-01

    Purpose Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS) magnetic resonance spectroscopy (MRS) and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters. Materials and methods Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32–75 years) with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1) were suspicious for malignancy on mammography or ultrasound (US), 2) were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB) 3) underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) and positron emission tomography-computed tomography (PET-CT), and 4) had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER), maximum standardized FDG uptake value (SUV max), apparent diffusion coefficient (ADC), and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA) to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters. Results In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in

  12. Gradient Weight in Phonology

    ERIC Educational Resources Information Center

    Ryan, Kevin Michael

    2011-01-01

    Research on syllable weight in generative phonology has focused almost exclusively on systems in which weight is treated as an ordinal hierarchy of clearly delineated categories (e.g. light and heavy). As I discuss, canonical weight-sensitive phenomena in phonology, including quantitative meter and quantity-sensitive stress, can also treat weight…

  13. Polydentate-ligand-supported self-assembly of heterometallic T-shaped Co4RE (RE = Gd, Tb, Y) clusters: synthesis, structure and magnetism.

    PubMed

    Ke, Hongshan; Zhao, Lang; Guo, Yang; Tang, Jinkui

    2012-08-28

    A series of mixed-valent heterometallic pentanuclear Co(III)(3)Co(II)RE(III) (RE = Gd (1), Tb (2), Y (3)) clusters have been rationally assembled by taking advantage of a bifunctional ligand with o-vanillin and tripodal tris(hydroxymethyl)aminomethane units. Structural determinations reveal that all compounds are isomorphous and possess a T-shaped Co(4)RE core, which comprises two nearly linear Co(2)RE subunits sharing a common RE ion. Their magnetic properties were thoroughly studied. The static magnetic susceptibility studies of 1 demonstrate the presence of weak ferromagnetic interactions between the magnetic centres and magnetic anisotropy reflected by the single ion zero-field splitting (ZFS) D term. Both 1 and 2 behave magnetically as heterodinuclear metal systems, while the magnetic behaviour of 3 is identical to an isolated Co(II) ion. Moreover, alternating-current susceptibility measurements did not exhibit any out-of-phase signal, suggesting that slow magnetic relaxation is absent above 2 K within them. These isomorphous Co(4)RE clusters offer an opportunity to systematically probe the contribution of different metal ions to the overall magnetic behaviour in Co(II)-RE(III) systems. PMID:22767361

  14. Kriging without negative weights

    SciTech Connect

    Szidarovszky, F.; Baafi, E.Y.; Kim, Y.C.

    1987-08-01

    Under a constant drift, the linear kriging estimator is considered as a weighted average of n available sample values. Kriging weights are determined such that the estimator is unbiased and optimal. To meet these requirements, negative kriging weights are sometimes found. Use of negative weights can produce negative block grades, which makes no practical sense. In some applications, all kriging weights may be required to be nonnegative. In this paper, a derivation of a set of nonlinear equations with the nonnegative constraint is presented. A numerical algorithm also is developed for the solution of the new set of kriging equations.

  15. Magnetic suspension and balance system (MSBS) advanced study.I - System design

    NASA Technical Reports Server (NTRS)

    Boom, Roger W.; Abdelsalam, Mostafa K.; Eyssa, Yehia M.; Mcintosh, Glen E.

    1987-01-01

    A magnetic suspension and balance system is designed to support models of aircraft or other objects in wind tunnels by means of magnetic forces. Major design improvements have been achieved, resulting in reductions of the system size, weight, and cost. These improvements are due to: (1) the use of holmium in the model core to increase its magnetic moment, (2) the use of a powerful new permanent magnet material in the model wings, (3) a new arrangement for the roll coils, and (4) the use of a nonmetallic structure to eliminate eddy current losses. The conceptual design of the holmium core superconductive solenoid and of the new permanent magnet wing assembly is described in detail. The discussion includes comparisons of the pole strengths for different model core magnets, the design of a superconducting solenoid and cryostat, and the analysis of model wing magnetic requirements.

  16. The psychological ramifications of weight management.

    PubMed

    Miller-Kovach, K; Hermann, M; Winick, M

    1999-05-01

    It has long been believed that food restriction leads to psychological disturbances, including depression, preoccupation with food, and binge eating. However, recent studies suggest that comprehensive weight loss programs that incorporate behavioral treatment, diet change, and encouragement of physical activity in fact can improve the psychological state, including mood. A study conducted on subjects participating in the Weight Watchers program demonstrated positive psychological changes and improved quality of life. These changes may help motivate overweight people to maintain the physical activity and nutritional practices necessary to lose and maintain weight. Programs that include group support, like Weight Watchers, have been associated with psychological benefits independent of the amount of weight lost. Furthermore, dieters who regain lost weight do not appear to experience adverse psychological consequences. The development or exacerbation of bulimia has been linked by some authors to strict dieting, but more moderate weight control programs do not appear to produce disordered eating and may help reduce binge eating among overweight people. Individuals who successfully lose and maintain weight have been shown to experience improved mood, self-confidence, and quality of life. Additionally, decreasing levels of psychological and behavioral symptoms have been associated with increasing duration of weight loss maintenance. It can be concluded that quality of life and other psychological measures improve in individuals on comprehensive weight management programs. PMID:10839702

  17. Freely oriented portable superconducting magnet

    DOEpatents

    Schmierer, Eric N.; Prenger, F. Coyne; Hill, Dallas D.

    2010-01-12

    A freely oriented portable superconducting magnet is disclosed. Coolant is supplied to the superconducting magnet from a repository separate from the magnet, enabling portability of the magnet. A plurality of support assemblies structurally anchor and thermally isolate the magnet within a thermal shield. A plurality of support assemblies structurally anchor and thermally isolate the thermal shield within a vacuum vessel. The support assemblies restrain movement of the magnet resulting from energizing and cooldown, as well as from changes in orientation, enabling the magnet to be freely orientable.

  18. Substitution of Ni for Fe in superconducting Fe0.98Te0.5Se0.5 depresses the normal-state conductivity but not the magnetic spectral weight

    SciTech Connect

    Wang, Jinghui; Zhong, Ruidan; Li, Shichao; Gan, Yuan; Xu, Zhijun; Zhang, Cheng; Ozaki, T.; Matsuda, M.; Zhao, Yang; Li, Qiang; Xu, Guangyong; Gu, Genda; Tranquada, J. M.; Birgeneau, R. J.; Wen, Jinsheng

    2015-01-05

    We have performed systematic resistivity and inelastic neutron scattering measurements on Fe₀.₉₈₋zNizTe₀.₅Se₀.₅ samples to study the impact of Ni substitution on the transport properties and the low-energy (≤ 12 meV) magnetic excitations. It is found that, with increasing Ni doping, both the conductivity and superconductivity are gradually suppressed; in contrast, the low-energy magnetic spectral weight changes little. Comparing with the impact of Co and Cu substitution, we find that the effects on conductivity and superconductivity for the same degree of substitution grow systematically as the atomic number of the substituent deviates from that of Fe. The impact of the substituents as scattering centers appears to be greater than any contribution to carrier concentration. The fact that low-energy magnetic spectral weight is not reduced by increased electron scattering indicates that the existence of antiferromagnetic correlations does not depend on electronic states close to the Fermi energy.

  19. Magnetic Liquids

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Ferrofluidics Corporation's recent innovation is a spindle for rotating computer discs that supports the disc's rotating shaft on a film of magnetic fluid instead of conventional ball bearings. According to its developers, the spindle offers greatly increased rotational stability, meaning substantially reduced vibration and mechanical noise, and non- repeatable runout. This allows disc drives to store two to 10 times more information.

  20. Impact of parental weight status on weight loss efforts in Hispanic children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Parents have been shown to play an important role in weight loss for children. Parents are typically involved either as models for change or as supporters of children's weight loss efforts. It is likely that overweight/obese parents will need to be involved in changing the environment for themselv...

  1. Weight gain - unintentional

    MedlinePlus

    ... trying to do so can have many causes. Metabolism slows down as you age . This can cause weight gain if you eat too much, eat the wrong foods, or do not get enough exercise. Drugs that can cause weight gain include: Birth control ...

  2. Weight loss and alcohol

    MedlinePlus

    ... weight gain in a couple of ways. First, alcohol is high in calories. Some mixed drinks can contain as many calories as a meal, but without the nutrients. You also may make poor food choices ... to cut out all alcohol if you are trying to lose weight, you ...

  3. Exercise and Weight Control.

    ERIC Educational Resources Information Center

    Katch, Victor L.

    This paper describes a number of factors which go into determining weight. The paper describes what calories are, how caloric expenditure is measured, and why caloric expenditure is different for different people. The paper then outlines the way the body tends to adjust food intake and exercise to maintain a constant body weight. It is speculated…

  4. Anthocyanins and weight loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review evaluated the available scientific literature relative to anthocyanins and weight loss and/or obesity with mention of other effects of anthocyanins on pathologies that are closely related to obesity. Although there is considerable popular press concerning anthocyanins and weight loss, th...

  5. Mathematics in Weighting.

    ERIC Educational Resources Information Center

    Francis, Richard L.

    1992-01-01

    Presents the template method developed by Galileo for calculating areas of geometric shapes constructed of uniform density and thickness. The method compares the weight of a shape of known area to the weight of a shape of unknown area. Applies this hands-on method to problems involving calculus, Pythagorean's theorem, and cycloids. (MDH)

  6. Weight and Diabetes

    MedlinePlus

    ... in a person's diabetes management plan. Weight and Type 1 Diabetes If a person has type 1 diabetes but hasn't been treated yet, he or she often loses weight. In type 1 diabetes, the body can't use glucose (pronounced: GLOO- ...

  7. Labor Supply and Weight

    ERIC Educational Resources Information Center

    Lakdawalla, Darius; Philipson, Tomas

    2007-01-01

    We use panel data from the National Longitudinal Survey of Youth to investigate on-the-job exercise and weight. For male workers, job-related exercise has causal effects on weight, but for female workers, the effects seem primarily selective. A man who spends 18 years in the most physical fitness-demanding occupation is about 25 pounds (14…

  8. Rapid weight loss

    MedlinePlus

    ... 22990030 www.ncbi.nlm.nih.gov/pubmed/22990030 . Weight-control Information NetworkNational Institute of Diabetes and Digestive and ... www.niddk.nih.gov/health-information/health-topics/weight-control/very-low-calorie-diets/Pages/very-low-calorie- ...

  9. Weight discrimination and bullying.

    PubMed

    Puhl, Rebecca M; King, Kelly M

    2013-04-01

    Despite significant attention to the medical impacts of obesity, often ignored are the negative outcomes that obese children and adults experience as a result of stigma, bias, and discrimination. Obese individuals are frequently stigmatized because of their weight in many domains of daily life. Research spanning several decades has documented consistent weight bias and stigmatization in employment, health care, schools, the media, and interpersonal relationships. For overweight and obese youth, weight stigmatization translates into pervasive victimization, teasing, and bullying. Multiple adverse outcomes are associated with exposure to weight stigmatization, including depression, anxiety, low self-esteem, body dissatisfaction, suicidal ideation, poor academic performance, lower physical activity, maladaptive eating behaviors, and avoidance of health care. This review summarizes the nature and extent of weight stigmatization against overweight and obese individuals, as well as the resulting consequences that these experiences create for social, psychological, and physical health for children and adults who are targeted. PMID:23731874

  10. Distribution of pregnancy-related weight measures

    PubMed Central

    Woolcott, Christy; Dodds, Linda; Ashley-Martin, Jillian; Piccinini-Vallis, Helena

    2016-01-01

    Objective To describe the distribution of prepregnancy body mass index (BMI), gestational weight gain, and interpregnancy weight change. Design Descriptive epidemiologic study using the Nova Scotia Atlee Perinatal Database. Setting Nova Scotia, 2003 to 2013. Participants Included were 63 355 pregnancies in women aged 20 years and older. Analyses of gestational weight gain were restricted to 54 289 singleton pregnancies. Analyses of interpregnancy weight change included 22 890 pairs of successive pregnancies. Main outcome measures Prepregnancy BMI; gestational weight gain (the difference between delivery and prepregnancy weight adjusted for length of gestation); and interpregnancy weight change (the difference in prepregnancy weight between successive pregnancies). Results The median (interquartile range [IQR]) prepregnancy BMI was 24.7 kg/m2 (21.7 to 29.4 kg/m2). Fewer than half (48.5%) of the pregnancies were in normal-weight women, 24.6% were in overweight women, and 23.0% were in obese women. The median (IQR) weight loss needed for women who entered pregnancy overweight or obese to be within the normal range was 13.2 kg (5.7 to 25.2 kg). The median (IQR) gestational weight gain was 14.9 kg (11.0 to 19.1 kg). Inadequate weight gain was observed in 15.8% of women and of these women, half were below the recommended amount by at least 2.2 kg. Excess gestational weight gain was observed in 57.9% of pregnancies, and among these, half were above the recommended amount by at least 4.8 kg. The median (IQR) interpregnancy weight change was 2.3 kg (−0.9 to 6.8 kg). Most (57.2%) women gained more than 1 kg between pregnancies and 24.6% lost 1 kg or more between pregnancies. Conclusion In Nova Scotia, both inadequate and excess pregnancy-related weight are prevalent, although the latter is more common than the former. Strategies are needed to promote healthier weight in reproductive-aged women, optimize gestational weight gain, and support postpartum weight management.

  11. Do dietary supplements help promote weight loss?

    PubMed

    Bell, Stacey J; Van Ausdal, Wendy; Grochoski, Greg

    2009-01-01

    As two-thirds of the US population is overweight or obese, new strategies are needed to help individuals safely and effectively lose weight. One option is to use dietary supplements, but not all supplements that are touted for weight loss have published clinical support for efficacy. The purpose of this article was to identify all published articles on dietary supplements for weight loss. Effectiveness of these supplements was defined as promoting 1-2 lb of weight loss each week. Although several dozen different dietary supplements are sold, only 14 published studies were identified. Four individual ingredients and three blends of ingredients were considered to be effective. Additionally, we compared weight loss from these dietary supplements to over-the-counter (OTC) orlistat (alli™, GlaxoSmithKline, Brentford, UK). Five single ingredients and three blends of ingredients produced more weight loss than OTC orlistat. Persons who use dietary supplements for weight management, counsel patients on how to lose weight, and retailers who sell dietary supplements, should become familiar with those supplements only that are effective at producing weight loss to assure the best results. PMID:22435353

  12. Seismometer using a vertical long natural-period rotational pendulum with magnetic levitation

    NASA Astrophysics Data System (ADS)

    Otake, Yuji; Araya, Akito; Hidano, Kazuo

    2005-05-01

    We have demonstrated a highly sensitive/wideband vertical-component seismometer using an astatic rotational pendulum to obtain a long natural period. This seismometer employs magnetic levitation for removing any parasitic resonances of a spring to support a weight due to gravity and the thermal dependence of the spring constant. The pendulum has a cylindrical plunger-type permanent magnet that has a weight at one side of its end edge. The plunger magnet is inserted into a uniform magnetic field generated by a window-frame-type permanent magnet, and attached to two crossed-leaf spring hinges as a rotational axis outside of the bore of the magnet. Magnetic forces applied to the plunger magnet counterbalance the gravitational force at the weight. To realize stable operation of the rotational pendulum without any unnecessary movements of the plunger magnet, a tilt of lines of the magnetic force in the bore of the window-frame magnet was compensated by a tilted magnetic-pole surface near to its opening. The field uniformity reached 10-4 owing to this compensation. The thermal dependence of a magnetic field strength of about 10-3/K was also compensated by as much as 9×10-5/K by Ni-Fe metal having a negative permeability coefficient. The metal was attached along the sidewalls of the window-frame magnet. To determine the feedback control parameters for a feedback control seismometer, the natural period of a prototype rotational pendulum was measured. It was more than 8s, and was able to be changed from 5to8s by using an additional magnetic spring, similar to the voice coil actuator of a speaker. This change was in accordance with theoretical calculations, and showed that the pendulum movement did not include a big nonlinearity caused by the tilt of the lines of the magnetic force. No parasitic resonances were found during experiments. A velocity feedback-control circuit and a capacitance position detector to measure the weight position were applied to the rotational

  13. Seismometer using a vertical long natural-period rotational pendulum with magnetic levitation

    SciTech Connect

    Otake, Yuji; Araya, Akito; Hidano, Kazuo

    2005-05-15

    We have demonstrated a highly sensitive/wideband vertical-component seismometer using an astatic rotational pendulum to obtain a long natural period. This seismometer employs magnetic levitation for removing any parasitic resonances of a spring to support a weight due to gravity and the thermal dependence of the spring constant. The pendulum has a cylindrical plunger-type permanent magnet that has a weight at one side of its end edge. The plunger magnet is inserted into a uniform magnetic field generated by a window-frame-type permanent magnet, and attached to two crossed-leaf spring hinges as a rotational axis outside of the bore of the magnet. Magnetic forces applied to the plunger magnet counterbalance the gravitational force at the weight. To realize stable operation of the rotational pendulum without any unnecessary movements of the plunger magnet, a tilt of lines of the magnetic force in the bore of the window-frame magnet was compensated by a tilted magnetic-pole surface near to its opening. The field uniformity reached 10{sup -4} owing to this compensation. The thermal dependence of a magnetic field strength of about 10{sup -3}/K was also compensated by as much as 9x10{sup -5}/K by Ni-Fe metal having a negative permeability coefficient. The metal was attached along the sidewalls of the window-frame magnet. To determine the feedback control parameters for a feedback control seismometer, the natural period of a prototype rotational pendulum was measured. It was more than 8 s, and was able to be changed from 5 to 8 s by using an additional magnetic spring, similar to the voice coil actuator of a speaker. This change was in accordance with theoretical calculations, and showed that the pendulum movement did not include a big nonlinearity caused by the tilt of the lines of the magnetic force. No parasitic resonances were found during experiments. A velocity feedback-control circuit and a capacitance position detector to measure the weight position were applied to

  14. Primary anorexia nervosa (weight phobia) in males.

    PubMed Central

    Hasan, M. K.; Tibbetts, R. W.

    1977-01-01

    Ten cases of primary anorexia nervosa (weight phobia) in males (as against 196 females) have been treated in the United Birmingham Hospitals over 19 years. A discrete syndromes appears to exist with much to support the view that it is the counterpart of primary anorexia nervosa in the female. Six illustrative case histories are described briefly. The heavy loading with consistent abnormalities of psychiatric interest makes it very probable that weight phobia is primarily a psychiatric disorder. PMID:870891

  15. Optimally weighted L(2) distance for functional data.

    PubMed

    Chen, Huaihou; Reiss, Philip T; Tarpey, Thaddeus

    2014-09-01

    Many techniques of functional data analysis require choosing a measure of distance between functions, with the most common choice being L2 distance. In this article we show that using a weighted L2 distance, with a judiciously chosen weight function, can improve the performance of various statistical methods for functional data, including k-medoids clustering, nonparametric classification, and permutation testing. Assuming a quadratically penalized (e.g., spline) basis representation for the functional data, we consider three nontrivial weight functions: design density weights, inverse-variance weights, and a new weight function that minimizes the coefficient of variation of the resulting squared distance by means of an efficient iterative procedure. The benefits of weighting, in particular with the proposed weight function, are demonstrated both in simulation studies and in applications to the Berkeley growth data and a functional magnetic resonance imaging data set. PMID:26228660

  16. Light-weight plastination.

    PubMed

    Steinke, Hanno; Rabi, Suganthy; Saito, Toshiyuki; Sawutti, Alimjan; Miyaki, Takayoshi; Itoh, Masahiro; Spanel-Borowski, Katharina

    2008-11-20

    Plastination is an excellent technique which helps to keep the anatomical specimens in a dry, odourless state. Since the invention of plastination technique by von Hagens, research has been done to improve the quality of plastinated specimens. In this paper, we have described a method of producing light-weight plastinated specimens using xylene along with silicone and in the final step, substitute xylene with air. The finished plastinated specimens were light-weight, dry, odourless and robust. This method requires less use of resin thus making the plastination technique more cost-effective. The light-weight specimens are easy to carry and can easily be used for teaching. PMID:18752934

  17. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Mirijanian, James; Pavell, James

    2015-05-01

    The Nuclear Magnetic Resonance Gyroscope (NMRG) is being developed by the Northrop Grumman Corporation (NGC). Cold and hot atom interferometer based gyroscopes have suffered from Size, Weight, and Power (SWaP) challenges and limits in bandwidth, scale factor stability, dead time, high rotation rate, vibration, and acceleration. NMRG utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as a reference for determining rotation, providing continuous measurement, high bandwidth, stable scale factor, high rotation rate measurement, and low sensitivity to vibration and acceleration in a low SWaP package. The sensitivity to vibration has been partially tested and demonstrates no measured sensitivity within error bars. Real time closed loop implementation of the sensor significantly decreases environmental and systematic sensitivities and supports a compact and low power digital signal processing and control system. Therefore, the NMRG technology holds great promise for navigation grade performance in a low cost SWaP package. The poster will describe the history, operation, and design of the NMRG. General performance results will also be presented along with recent vibration test results.

  18. Magnetorheological torque transmission devices with permanent magnets

    NASA Astrophysics Data System (ADS)

    Böse, H.; Gerlach, T.; Ehrlich, J.

    2013-02-01

    A novel type of magnetorheological (MR) clutch whose magnetic circuit contains a combination of a permanent magnet and an electromagnet is described. Without the support of the electromagnet, the permanent magnet generates a magnetic field in the MR fluid shear gap which enables the MR clutch to transmit a torque without the supply of any electric energy. Hence, the operational states of this clutch are reversed with respect to the common MR clutches equipped with an electromagnet only. Three different MR clutches with hybrid magnetic circuits containing permanent magnet and electromagnet were designed, manufactured and tested. The three clutches differ in their number of mechanical parts which can rotate with respect to each other as well as in their size and weight and in their maximum transmittable torque. The largest MR clutch is capable to transmit torques up to nearly 800 Nm. The designs of the three novel MR clutches and the results of the mechanical tests upon variation of the coil current are presented in this paper.

  19. Thyroid and Weight

    MedlinePlus

    ... Differences in BMRs are associated with changes in energy balance. Energy balance reflects the difference between the amount of ... such as amphetamines, animals often have a negative energy balance which leads to weight loss. Based on ...

  20. Losing weight after pregnancy

    MedlinePlus

    ... behavioral guidelines for post-partum weight control. BMC Pregnancy and Childbirth . 2014;14. Accessed Nov. 24, 2014. Mottola MF. Exercise prescription for overweight and obese women: pregnancy and ...