927 resultados para ARM, Intensity after demagnetization
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Background The body of evidence related to breast-cancer-related lymphoedema incidence and risk factors has substantially grown and improved in quality over the past decade. We assessed the incidence of unilateral arm lymphoedema after breast cancer and explored the evidence available for lymphoedema risk factors. Methods We searched Academic Search Elite, Cumulative Index to Nursing and Allied Health, Cochrane Central Register of Controlled Trials (clinical trials), and Medline for research articles that assessed the incidence or prevalence of, or risk factors for, arm lymphoedema after breast cancer, published between January 1, 2000, and June 30, 2012. We extracted incidence data and calculated corresponding exact binomial 95% CIs. We used random effects models to calculate a pooled overall estimate of lymphoedema incidence, with subgroup analyses to assess the effect of different study designs, countries of study origin, diagnostic methods, time since diagnosis, and extent of axillary surgery. We assessed risk factors and collated them into four levels of evidence, depending on consistency of findings and quality and quantity of studies contributing to findings. Findings 72 studies met the inclusion criteria for the assessment of lymphoedema incidence, giving a pooled estimate of 16·6% (95% CI 13·6–20·2). Our estimate was 21·4% (14·9–29·8) when restricted to data from prospective cohort studies (30 studies). The incidence of arm lymphoedema seemed to increase up to 2 years after diagnosis or surgery of breast cancer (24 studies with time since diagnosis or surgery of 12 to <24 months; 18·9%, 14·2–24·7), was highest when assessed by more than one diagnostic method (nine studies; 28·2%, 11·8–53·5), and was about four times higher in women who had an axillary-lymph-node dissection (18 studies; 19·9%, 13·5–28·2) than it was in those who had sentinel-node biopsy (18 studies; 5·6%, 6·1–7·9). 29 studies met the inclusion criteria for the assessment of risk factors. Risk factors that had a strong level of evidence were extensive surgery (ie, axillary-lymph-node dissection, greater number of lymph nodes dissected, mastectomy) and being overweight or obese. Interpretation Our findings suggest that more than one in five women who survive breast cancer will develop arm lymphoedema. A clear need exists for improved understanding of contributing risk factors, as well as of prevention and management strategies to reduce the individual and public health burden of this disabling and distressing disorder.
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Research Review on: Mueller X, Tinguely F, Tevaearai H, Revelly J, Chiolero R & Von Segess L. Pain location, distribution and intensity after cardiac surgery. Chest 2000; 118(2):391.396.
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Objective: To evaluate the effect of robot-mediated therapy on arm dysfunction post stroke. Design: A series of single-case studies using a randomized multiple baseline design with ABC or ACB order. Subjects (n = 20) had a baseline length of 8, 9 or 10 data points. They continued measurement during the B - robot-mediated therapy and C - sling suspension phases. Setting: Physiotherapy department, teaching hospital. Subjects: Twenty subjects with varying degrees of motor and sensory deficit completed the study. Subjects attended three times a week, with each phase lasting three weeks. Interventions: In the robot-mediated therapy phase they practised three functional exercises with haptic and visual feedback from the system. In the sling suspension phase they practised three single-plane exercises. Each treatment phase was three weeks long. Main measures: The range of active shoulder flexion, the Fugl-Meyer motor assessment and the Motor Assessment Scale were measured at each visit. Results: Each subject had a varied response to the measurement and intervention phases. The rate of recovery was greater during the robot-mediated therapy phase than in the baseline phase for the majority of subjects. The rate of recovery during the robot-mediated therapy phase was also greater than that during the sling suspension phase for most subjects. Conclusion: The positive treatment effect for both groups suggests that robot-mediated therapy can have a treatment effect greater than the same duration of non-functional exercises. Further studies investigating the optimal duration of treatment in the form of a randomized controlled trial are warranted.
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We have developed a haptic-based approach for retraining of interjoint coordination following stroke called time-independent functional training (TIFT) and implemented this mode in the ARMin III robotic exoskeleton. The ARMin III robot was developed by Drs. Robert Riener and Tobias Nef at the Swiss Federal Institute of Technology Zurich (Eidgenossische Technische Hochschule Zurich, or ETH Zurich), in Zurich, Switzerland. In the TIFT mode, the robot maintains arm movements within the proper kinematic trajectory via haptic walls at each joint. These arm movements focus training of interjoint coordination with highly intuitive real-time feedback of performance; arm movements advance within the trajectory only if their movement coordination is correct. In initial testing, 37 nondisabled subjects received a single session of learning of a complex pattern. Subjects were randomized to TIFT or visual demonstration or moved along with the robot as it moved though the pattern (time-dependent [TD] training). We examined visual demonstration to separate the effects of action observation on motor learning from the effects of the two haptic guidance methods. During these training trials, TIFT subjects reduced error and interaction forces between the robot and arm, while TD subject performance did not change. All groups showed significant learning of the trajectory during unassisted recall trials, but we observed no difference in learning between groups, possibly because this learning task is dominated by vision. Further testing in stroke populations is warranted.
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BACKGROUND Quantitative light intensity analysis of the strut core by optical coherence tomography (OCT) may enable assessment of changes in the light reflectivity of the bioresorbable polymeric scaffold from polymer to provisional matrix and connective tissues, with full disappearance and integration of the scaffold into the vessel wall. The aim of this report was to describe the methodology and to apply it to serial human OCT images post procedure and at 6, 12, 24 and 36 months in the ABSORB cohort B trial. METHODS AND RESULTS In serial frequency-domain OCT pullbacks, corresponding struts at different time points were identified by 3-dimensional foldout view. The peak and median values of light intensity were measured in the strut core by dedicated software. A total of 303 corresponding struts were serially analyzed at 3 time points. In the sequential analysis, peak light intensity increased gradually in the first 24 months after implantation and reached a plateau (relative difference with respect to baseline [%Dif]: 61.4% at 12 months, 115.0% at 24 months, 110.7% at 36 months), while the median intensity kept increasing at 36 months (%Dif: 14.3% at 12 months, 75.0% at 24 months, 93.1% at 36 months). CONCLUSIONS Quantitative light intensity analysis by OCT was capable of detecting subtle changes in the bioresorbable strut appearance over time, and could be used to monitor the bioresorption and integration process of polylactide struts.
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A combination of high sedimentation rates and high concentrations of magnetic grains in cores from Ocean Drilling Program Leg 126 resulted in the recovery of detailed direction and intensity records of the Brunhes/Matuyama geomagnetic polarity reversal. Virtual geomagnetic poles (VGPs) computed from azimuthally oriented samples taken from the cores of Hole 792A in the western Izu-Bonin forearc basin reveal that the geomagnetic pole persisted at moderate to high southern latitudes for several thousand years before a rapid migration to northern latitudes. Alternating-field demagnetization behavior, as well as NRM, NRM/ARM, and NRM/IRM intensities for samples from this same interval, and the NRM/IRM intensities derived from unoriented core samples from Holes 790C and 791B, drilled in the ~100-km distant Sumisu Rift, all suggest that the dipole field oscillated widely in intensity before the reversal. The fast polarity change occurred at the low point of an ~1100-yr field intensity cycle. This "reversal cycle" immediately followed earlier intensity cycles whose peaks rivaled or surpassed the normalized intensities of discrete samples from well above and below the reversal interval; furthermore, the troughs indicate a much diminished dipole field at their nadir.
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We present a high-resolution magnetostratigraphy and relative paleointensity (RPI) record derived from the upper 85 meters of IODP Site U1336, an equatorial Pacific early to middle Miocene succession recovered during Expedition 320/321. The magnetostratigraphy is well resolved with reversals typically located to within a few centimeters resulting in a well-constrained age model. The lowest normal polarity interval, from 85 to 74.87 meters, is interpreted as the upper part of Chron C6n (18.614-19.599 Ma). Another 33 magnetozones occur from 74.87 to 0.85 m, which are interpret to represent the continuous sequence of chrons from Chron C5Er (18.431-18.614 Ma) up to the top of Chron C5An.1n (12.014 Ma). We identify three new possible subchrons within Chron C5Cn.1n, Chron 5Bn.1r, and C5ABn. Sedimentation rates vary from about 7 to 15 m/Myr with a mean of about 10 m/Myr. We observe rapid, apparent changes in the sedimentation rate at geomagnetic reversals between ~16 and 19 Ma that indicate a calibration error in geomagnetic polarity timescale (ATNTS2004). The remanence is carried mainly by non-interacting particles of fine-grained magnetite, which have FORC distributions characteristic of biogenic magnetite. Given the relative homogeneity of the remanence carriers throughout the 85-m-thick succession and the quality with which the remanence is recorded, we have constructed a relative paleointensity (RPI) record that provides new insights into middle Miocene geomagnetic field behavior. The RPI record indicates a gradual decline in field strength between 18.5 Ma and 14.5 Ma, and indicates no discernible link between RPI and either chron duration or polarity state.
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A 160 m mostly turbiditic late Pleistocene sediment sequence (IODP Expedition 308, Hole U1319A) from the Brazos-Trinity intraslope basin system off Texas was investigated with paleo- and rock magnetic methods. Numerous layers depleted in iron oxides and enriched by the ferrimagnetic iron-sulfide mineral greigite (Fe3S4) were detected by diagnostic magnetic properties. From the distribution of these layers, their stratigraphic context and the present geochemical zonation, we develop two conceptual reaction models of greigite formation in non-steady depositional environments. The "sulfidization model" predicts single or twin greigite layers by incomplete transformation of iron monosulfides with polysulfides around the sulfate methane transition (SMT). The "oxidation model" explains greigite formation by partial oxidation of iron monosulfides near the iron redox boundary during periods of downward shifting oxidation fronts. The stratigraphic record provides evidence that both these greigite formation processes act here at typical depths of about 12-14 mbsf and 3-4 mbsf. Numerous "fossil" greigite layers most likely preserved by rapid upward shifts of the redox zonation denote past SMT and sea floor positions characterized by stagnant hemipelagic sedimentation conditions. Six diagenetic stages from a pristine magnetite-dominated to a fully greigite-dominated magnetic mineralogy were differentiated by combination of various hysteresis and remanence parameters.
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Detailed paleomagnetic investigations are reported for 283 specimens, sampled from three closely spaced Ocean Drilling Program Leg 135 cores from the Lau Basin. These specimens cover three rather similar records of the reversed Cobb Mountain short polarity event, having an age of about 1.12 m.y. On the basis of a very detailed subsampling every 0.6 cm, we found that the transition times for the Cobb Mountain geomagnetic polarity event, as seen in the three Lau Basin sediment records, appear to have been as short as 0.6-1.0 k.y., although the duration of the normal-polarity event itself lasted only about 17 ± 4 k.y. The older (R to N) transition as well as the younger (N to R) transition show virtual geomagnetic paths roughly along the Americas, but shifted some 30° ± 10° to the east. These paths conflict with Cobb Mountain transition paths recorded in sediments from the Labrador Sea and the North Atlantic, but they are in fair accordance with sediment records from the Celebes and Sulu seas when corrected for differences in site longitude, suggesting that the transitional fields are dominated by nonaxial, high-order spherical harmonics.
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The upper sections of Deep Sea Drilling Project Sites 576 (32°21.4'N, 164°16.5'E) and 578 (33°55.6'N, 151°37.7'E) both have stable detrital remanence that can be correlated with the standard reversal stratigraphy. Site 576 contains all reversals above the base of the Gilbert Epoch (5 m.y.) at about 25 m, whereas Site 578 contains a remarkable section of about 60 reversals extending to Anomaly 5B (15 m.y.) at about 150 m sub-bottom depth. In both cases, the paleomagnetic stratigraphy breaks down when accumulation rates drop below 2 m/m.y. At both sites, authigenic manganiferous clays deposited from 70 to 16 m.y. ago accumulated at about 0.4 m/m.y. Similarly, at both sites, the Pleistocene pulse of eolian debris increased accumulation rates by about 6 m/m.y.**2. From 16 to 2 m.y. ago, however, sediment accumulated at Site 578 about five times as rapidly as at Site 576, apparently because of augmented input to the western site by bottom currents.
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Sediments recovered during Leg 90 (Sites 587-594, plus Site 586 cored during Leg 89) are, in general, extremely weakly magnetized carbonate oozes and chalks with NRM intensities seldom greater than 0.05 µG. The quality of the paleomagnetic records deteriorates with increasing depth caused by the combined effects of removal of primary magnetic oxides by sulfate reduction processes and the dispersal of magnetic grains during compaction. Magnetic reversal sequences are generally recognizable back to the Gilbert, 3.4 to 5.35 m.y., except at equatorial Site 586 where only the Brunhes/Matuyama boundary could be identified. Longer reversal records were obtained at Site 588 (to Chron 13, about 13 m.y.) and Site 594 (base of Chron 5, about 5.9 m.y.). Sediments are characterized by extremely high calcium carbonate contents (90-100%) with almost no biosiliceous components. Blebs and streaks of pyrite are common, and the presence of iron sulfides with poor magnetic stabilities is suspected, although not yet positively identified. Viscous components of magnetization are common, sometimes to the extent of dominating the primary remanence, and there is evidence to suggest that a magnetic remanence is imparted during core recovery. Siliceous carbonate oozes provide better paleomagnetic records than pure carbonate oozes.
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Paleomagnetic studies were carried out on 23 basalt and 74 sediment samples from Leg 91 of the Deep Sea Drilling Project, recovered from a portion of the southwestern Pacific plate (24°S, 166°W) dating back to the Early Cretaceous to perhaps Late Jurassic. The expected geocentric axial dipole inclination at this latitude is -41°. The corrected mean stable inclination of -75° for the basalts indicates a paleolatitude of 63°S for their formation and thus 39° of northward motion during the last 100 m.y. Sediment inclinations steepen rapidly below 13-m depth in the core, suggesting little northward motion of this part of the Pacific plate until about 25 m.y. ago. Examination of the opaque minerals in polished section, as well as the Curie temperatures determined for six basalt samples, reveals no evidence of high- or intermediate-temperature oxidation and thus no reheating of the basement rock since its formation.