22 resultados para SCREW-SENSE INVERSION

em University of Queensland eSpace - Australia


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Purpose. The ability to sense the position of limb segments is a highly specialised proprioceptive function important for control of movement. Abnormal knee proprioception has been found in association with several musculoskeletal pathologies but whether nociceptive Stimulation can produce these proprioceptive changes is unclear. This study evaluated the effect of experimentally induced knee pain on knee joint position sense (JPS) in healthy individuals. Study design. Repeated measures, within-subject design. Methods. Knee JPS was tested in 16 individuals with no history of knee pathology under three experimental conditions: baseline control, a distraction task and knee pain induced by injection of hypertonic saline into the infrapatellar fat pad. Knee JPS was measured using active ipsilateral limb matching responses at 20degrees and 60degrees flexion whilst non-weightbearing (NWB) and 20degrees flexion single leg stance. During the tasks, the subjective perception of distraction and severity of pain were measured using 11-point numerical rating scales. Results. Knee JPS was not altered by acute knee pain in any of the positions tested. The distraction task resulted in poorer concentration, greater JPS absolute errors at 20degrees NWB, and greater variability in errors during the WB tests. There were no significant correlations between levels of pain and changes in JPS errors. Changes in JPS with pain and distraction were inversely related to baseline knee JPS variable error in all test positions (r = -0.56 to -0.91) but less related to baseline absolute error. Conclusion. Knee JPS is reduced by an attention-demanding task but not by experimentally induced pain. (C) 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.

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This study investigates the sense of belonging to a neighbourhood among 9445 women aged 73-78 years participating in the Australian Longitudinal Study on Women's Health. Thirteen items designed to measure sense of neighbourhood were included in the survey of the older women in 1999. Survey data provided a range of measures of demographic, social and health-related factors to assess scale construct validity. Factor analysis showed that seven of the items loaded on one factor that had good face validity and construct validity as a measure of the sense of neighbourhood. Two of the remaining items related to neighbourhood safety and comprised a factor. A better sense of neighbourhood was associated with better physical and mental health, lower stress, better social support and being physically active. Women who had lived longer at their present address had a better sense of belonging to their neighbourhood, as did women living in non-urban areas and who were better able to manage on their income. Feeling safe in the neighbourhood was least likely in urban areas, increased in rural townships, and was most likely in rural and remote areas. Older women living alone felt less safe, as did women who were less able to manage on their income. This study has identified two sets of items that form valid measures of aspects of the social environment of older women, namely the sense of neighbourhood and feelings of safety. These findings make a contribution to our understanding of the relationship between feelings of belonging to a neighbourhood and health in older women. (C) 2004 Elsevier Ltd. All rights reserved.

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This study explored the nature of two construals of meaning, benefit finding and sense making, in parents of a child with Asperger syndrome, and examined relations between both meaning constructs and the Double ABCX family stress model variables (initial stressor and pile-up of demands, appraisal, social support, coping strategies and adjustment) [H.I. McCubbin, J.M. Patterson, Social Stress and the Family: Advances and Developments in Family Stress Theory and Research, Haworth, New York, 1983, pp. 7-37]. A total of 59 parents completed questionnaires. Content analyses of parents' responses to questions inquiring about gains and sense making explanations revealed 8 benefit and 12 sense making themes. Results of correlations indicated that one or more of the meaning variables were related to each of the Double ABCX model predictors of parental adjustment. The meaning variables were positively related to adaptive coping processes: social support, self-efficacy, and problem-focused and emotional approach coping strategies. (C) 2004 Elsevier Ltd. All rights reserved.

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Ocular neovascularisation is the leading cause of blindness in developed countries and the most potent angiogenic factor associated with neovascularisation is vascular endothelial growth factor (VEGF). We have previously described a sense oligonucleotide (ODN-1) that possesses anti-human and rat VEGF activity. This paper describes the synthesis of lipid-lysine dendrimers and their subsequent ability to delivery ODN-1 to its target and mediate a reduction in VEGF concentration both in vitro and in vivo. Positively charged dendrimers were used to deliver ODN-1 into the nucleus of cultured D407 cells. The effects on VEGF mRNA transcription and protein expression were analysed using RT-PCR and ELISA, respectively. The most effective dendrimers in vitro were further investigated in vivo using an animal model of choroidal neovascularisation (CNV). All dendrimer/ODN-1 complexes mediated in a significant reduction in VEGF expression during an initial 24 hr period (40-60%). Several complexes maintained this level of VEGF reduction during a subsequent, second 24 hr period, which indicated protection of ODN-1 from the effects of endogenous nucleases. In addition, the transfection efficiency of dendrimers that possessed 8 positive charges (chi = 81(.)51%) was significantly better (P = 0(.)0036) than those that possessed 4 positive charges (chi = 56(.)8%). RT-PCR revealed a correlation between levels of VEGF protein mRNA. These results indicated that the most effective structural combination was three branched chains of intermediate length with 8 positive charges such as that found for dendrimer 4. Dendrimer 4 and 7/ODN-1 complexes were subsequently chosen for in vivo analysis. Fluorescein angiography demonstrated that both dendrimers significantly (P < 0(.)0001) reduced the severity of laser mediated CNV for up to two months post-injection. This study demonstrated that lipophilic, charged dendrimer mediated delivery of ODN-1 resulted in the down-regulation of in vitro VEGF expression. In addition, in vivo delivery of ODN-1 by two of the dendrimers resulted in significant inhibition of CNV in an inducible rat model. Time course studies showed that the dendrimer/ODN-1 complexes remained active for up to two months indicating the dendrimer compounds provided protection against the effects of nucleases. (C) 2004 Elsevier Ltd. All rights reserved.

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Since the 1980s, numerous studies conducted in the United States have attempted to estimate the prevalence of supplement use among the population (e.g., the National Health and Nutrition Survey and the National Health Interview Surveys). Despite these efforts, the true extent of supplement use is unclear. The literature pertaining to the prevalence of supplement use refers to a confusing array of ambiguous terms. Forming accurate conclusions about supplement use is confounded by differences in terminology and methodology between studies. Direct comparisons between studies are therefore inherently problematic. The emphasis in future investigations should be on standardizing the study design; recording data on daily, weekly, or even monthly use in order to establish the safety and efficacy of supplement use; and adopting a consistent, uniform definition of the term supplement.

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Galactomannan biosynthesis in legume seed endosperms involves two Golgi membrane-bound glycosyltransferases, mannan synthase and galactomannan galactosyltransferase (GMGT). GMGT specificity is an important factor regulating the distribution and amount of (1-->6)-alpha-galactose (Gal) substitution of the (1-->4)-beta-linked mannan backbone. The model legume Lotus japonicus is shown now to have endospermic seeds with endosperm cell walls that contain a high-Gal galactomannan (mannose [Man]/Gal = 1.2-1.3). Galactomannan biosynthesis in developing L. japonicus endosperms has been mapped, and a cDNA encoding a functional GMGT has been obtained from L. japonicus endosperms during galactomannan deposition. L. japonicus has been transformed with sense, antisense, and sense/antisense ("hairpin loop") constructs of the GMGT cDNA. Some of the sense, antisense, and sense/antisense transgenic lines exhibited galactomannans with altered (higher) Man/Gal values in their (T-1 generation) seeds, at frequencies that were consistent with posttranscriptional silencing of GMGT. For T-1 generation individuals, transgene inheritance was correlated with galactomannan composition and amount in the endosperm. All the azygous individuals had unchanged galactomannans, whereas those that had inherited a GMGT transgene exhibited a range of Man/Gal values, up to about 6 in some lines. For Man/Gal values up to 4, the results were consistent with lowered Gal substitution of a constant amount of mannan backbone. Further lowering of Gal substitution was accompanied by a slight decrease in the amount of mannan backbone. Microsomal membranes prepared from the developing T-2 generation endosperms of transgenic lines showed reduced GMGT activity relative to mannan synthase. The results demonstrate structural modification of a plant cell wall polysaccharide by designed regulation of a Golgi-bound glycosyltransferase.

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Changes in the position of the head and neck have been shown to introduce a systematic deviation in the end-point error of an upper limb pointing task. Although previous authors have attributed this to alteration of perceived target location, no studies have explored the effect of changes in head and neck position on the perception of limb position. This study investigated whether changes in head and neck position affect a specific component of movement performance, that is, the accuracy of joint position sense (JPS) at the elbow. Elbow JPS was tested with the neck in four positions: neutral, flexion, rotation and combined flexion/rotation. A target angle was presented passively with the neck in neutral, after a rest period; this angle was reproduced actively with the head and neck in one of the test positions. The potential effects of distraction from head movement were controlled for by performing a movement control in which the head and neck were in neutral for the presentation and reproduction of the target angle, but moved into flexion during the rest period. The absolute and variable joint position errors (JPE) were greater when the target angle was reproduced with the neck in the flexion, rotation, and combined flexion/rotation than when the head and neck were in neutral. This study suggests that the reduced accuracy previously seen in pointing tasks with changes in head position may be partly because of errors in the interpretation of arm position.

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We derive a master equation for a driven double quantum dot damped by an unstructured phonon bath, and calculate the spectral density. We find that bath-mediated photon absorption is important at relatively strong driving, and may even dominate the dynamics, inducing population inversion of the double-dot system. This phenomenon is consistent with recent experimental observations.

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Intestinal chiral inversion of ibuprofen is still lacking direct evidence. In a preliminary experiment, ibuprofen was found to undergo inversion in Caco-2 cells. This investigation was thus conducted to determine the characteristics and influence of some biochemical factors on the chiral inversion of ibuprofen in Caco-2 cells. The effects of substrate concentration (2.5-40 mu g/ml), cell density (0.5-2 x 10(6) cells/ well), content of serum (0-20%), coexistence of S ibuprofen (corresponding doses), sodium azide (10mm), exogenous Coenzyme A (CoA) (0.1 - 0.4 mm),. and palmitic acid (5-25 mu m) on inversion were examined. A stereoselective HPLC method based on the Chromasil-CHI-TBB column was developed for quantitative analysis of the drug in cell culture medium. The inversion ratio (F-i) and elimination rate constant were calculated as the indexes of inversion extent. Inversion of ibuprofen in Caeo-2 cells was found to be both dose and cell density dependent, indicating saturable characteristics. Addition of serum significantly inhibited the inversion, to an extent of 2.7 fold decrease at 20% content. Preexistence of S enantiomer exerted a significant inhibitory effect (p < 0.01 for all tests). Sodium azide decreased the inversion ratio from 0.43 to 0.32 (p < 0.01). Exogenous CoA and palmitic acid significantly promoted the inversion at all tested doses (p < 0.01 for all tests). This research provided strong evidence to the capacity and capability of intestinal chiral inversion. Although long incubation times up to 120 h were required, Caco-2 cells should be a suitable model for chiral inversion research of 2-APAs considering the human-resourced and well-defined characteristics from the present study.

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Special edition: The United Nations and international legal order - the case of the Juno Trader - on 18 December 2004, the International Tribunal for the Law of the Sea ordered the prompt release of a refrigerated cargo vessel and its cargo for fisheries violations in an exclusive economic zone - Tribunal unanimously decided that the vessel and cargo be released, upon posting of a bond in the form of a bank guarantee - crew should be free to leave without conditions - in this case, on prompt release, the Tribunal made valuable contributions to existing case law on the issue - shows that specialised tribunals may perform a decentralised application of the international rule of law - crystallises international fundamental standards of fairness and human rights.

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Background: It has been shown that perception of elbow joint position is affected by changes in head and neck position. Further, people with whiplash-associated disorders (WAD) present with deficits in upper limb coordination and movement. Objectives: This study is aimed to determine whether the effect of changes in head position on elbow joint position error (JPE) is more pronounced in people with WAD, and to determine whether this is related to the participant's pain and anxiety levels. Methods: Nine people with chronic and disabling WAD and 11 healthy people participated in this experiment. The ability to reproduce a position at the elbow joint was assessed after changes in the position of the head and neck to 30 degrees, and with the head in the midline. Pain was monitored in WAD participants. Results: Absolute elbow JPE with the head in neutral was not different between WAD and control participants (P = 0.5). Changes in the head and neck position increased absolute elbow JPE in the WAD group (P < 0.05), but did not affect elbow JPE in the control group (P = 0.4). There was a connection between pain during testing and the effect of changes in head position on elbow JPE (P < 0.05). Discussion: Elbow JPE is affected by movement of the head and neck, with smaller angles of neck rotation in people with WAD than in healthy individuals. This observation may explain deficits in upper limb coordination in people with WAD, which may be due to the presence of pain or reduced range of motion in this population.

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In this work, a new design concept in chest imaging for MRI application is presented. A focused, 8-element transceive torso phased array coil is designed to investigate transmitting focused B1 field deep within the torso to enhance signal intensity and use in conjunction with SENSE reconstruction technique. Hybrid FDTD/MOM method is used to accurately predict the RF behavior inside the human torso. The simulation results reported herein demonstrate the feasibility of the design concept which shows that B1 field focusing with SENSE reconstruction is achievable, and the 8-element transceive torso phased array coil has the advantage to be used in transmit and receive mode for optimum and fast chest imaging.