1,732 research outputs found

    Hybrid Angular- and Energy-Dispersive X-ray Diffraction Computed Tomography

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    X-ray diffraction is a material-specific technique, the results of which can be used as a material fingerprint to identify unknowns. In this paper we present an adaptation to a novel hybrid angular- and energy-dispersive X-ray diffraction technique, which, until now, has been limited in utility by sample thickness. Computed tomography techniques have been applied to spatially resolve the origin of the scattering signals and to reconstruct the diffraction pattern in each pixel. 2D cross-correlation has been used to compare the reconstructed data to a library of standards as a means of identifying the material present

    Early serial EEG in hypoxic ischaemic encephalopathy

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    Objectives: To perform early serial EEGs in infants with hypoxic ischaemic encephalopathy (HIE) and compare the findings with neurodevelopmental outcome.// Methods: Nine full-term neonates with HIE had simultaneous video-EEG polygraphic studies within 8 h of birth. The EEG was repeated at 12–24 h intervals. All surviving infants had a neurodevelopmental assessment at 1 year.// Results: Two infants had a normal or mildly abnormal EEG within 8 h of birth and neurodevelopmental outcome was normal. Seven infants had severely depressed background activity in the first 8 h of life. In 3 infants the EEG activity recovered within 12–24 h showing continuous activity with no or only minor abnormalities. All these infants had a normal outcome. The remaining 4 infants, who also had an initially inactive recording, subsequently developed severe background abnormalities. At follow-up, two infants had died and the remainder developed major neurological sequelae.// Conclusions: Early EEG is an excellent prognostic indicator for a favourable outcome if normal within the first 8 h of life and for a poor outcome if the background activity continues to be inactive or grossly abnormal beyond 8–12 h of life. However, an inactive or very depressed EEG within the first 8 h of life can be associated with good outcome if the EEG activity recovers within 12 h

    Training duration may not be a predisposing factor in potential maladaptations in talent development programmes that promote early specialisation in elite youth soccer

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    Purpose To determine whether training duration is a predisposing factor in potential maladaptations in talent development programmes that promote early specialisation in elite youth soccer. Methods Training times and type of 184 elite soccer players, from the under-9 to under-21 age groups (age 9.4 to 18.4 yrs; stature 1.38 to 1.82 m; body mass 32.2 to 76.2 kg) were recorded. Results Total training time progressively increased between the under-9 (268 ± 25 min/week) and under-14 (477 ± 19 min/week) groups with the majority of training time (96.5 ± 3.9%) consisting of soccer training and matches. Total training time then subsequently reduced from under-14 to under-15 (266 ± 77 min/week) groups, with no differences in training time between under-15 and under-21. Only under-15 to under-21 players completed resistance training; this inclusion coincided with a reduction in soccer training and match play when compared to time spent in these activities for younger groups (73.8 ± 3.2% of total training). Conclusion Data suggest that although the majority of training is focused on technical development, the training duration as a whole is unlikely to contribute to potential maladaptations in talent development programmes in elite youth soccer

    The Role of External Inputs and Internal Cycling in Shaping the Global Ocean Cobalt Distribution: Insights From the First Cobalt Biogeochemical Model

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    ©2018. The Authors. Cobalt is an important micronutrient for ocean microbes as it is present in vitamin B 12 and is a co-factor in various metalloenzymes that catalyze cellular processes. Moreover, when seawater availability of cobalt is compared to biological demands, cobalt emerges as being depleted in seawater, pointing to a potentially important limiting role. To properly account for the potential biological role for cobalt, there is therefore a need to understand the processes driving the biogeochemical cycling of cobalt and, in particular, the balance between external inputs and internal cycling. To do so, we developed the first cobalt model within a state-of-the-art three-dimensional global ocean biogeochemical model. Overall, our model does a good job in reproducing measurements with a correlation coefficient of > 0.7 in the surface and > 0.5 at depth. We find that continental margins are the dominant source of cobalt, with a crucial role played by supply under low bottom-water oxygen conditions. The basin-scale distribution of cobalt supplied from margins is facilitated by the activity of manganese-oxidizing bacteria being suppressed under low oxygen and low temperatures, which extends the residence time of cobalt. Overall, we find a residence time of 7 and 250 years in the upper 250 m and global ocean, respectively. Importantly, we find that the dominant internal resupply process switches from regeneration and recycling of particulate cobalt to dissolution of scavenged cobalt between the upper ocean and the ocean interior. Our model highlights key regions of the ocean where biological activity may be most sensitive to cobalt availability

    Training Load and Carbohydrate Periodization Practices of Elite Male Australian Football Players: Evidence of Fueling for the Work Required.

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    The authors aimed to quantify (a) the periodization of physical loading and daily carbohydrate (CHO) intake across an in-season weekly microcycle of Australian Football and (b) the quantity and source of CHO consumed during game play and training. Physical loading (via global positioning system technology) and daily CHO intake (via a combination of 24-hr recall, food diaries, and remote food photographic method) were assessed in 42 professional male players during two weekly microcycles comprising a home and away fixture. The players also reported the source and quantity of CHO consumed during all games (n = 22 games) and on the training session completed 4 days before each game (n = 22 sessions). The total distance was greater (p < .05) on game day (GD; 13 km) versus all training days. The total distance differed between training days, where GD-2 (8 km) was higher than GD-1, GD-3, and GD-4 (3.5, 0, and 7 km, respectively). The daily CHO intake was also different between training days, with reported intakes of 1.8, 1.4, 2.5, and 4.5 g/kg body mass on GD-4, GD-3, GD-2, and GD-1, respectively. The CHO intake was greater (p < .05) during games (59 ± 19 g) compared with training (1 ± 1 g), where in the former, 75% of the CHO consumed was from fluids as opposed to gels. Although the data suggest that Australian Football players practice elements of CHO periodization, the low absolute CHO intakes likely represent considerable underreporting in this population. Even when accounting for potential underreporting, the data also suggest Australian Football players underconsume CHO in relation to the physical demands of training and competition

    Ultrasound Does Not Detect Acute Changes in Glycogen in Vastus Lateralis of Man.

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    PURPOSE: To examine the validity of ultrasound (via cloud based software that measures pixilation intensity according to a scale of 0-100) to non-invasively assess muscle glycogen in human skeletal muscle. METHODS: In Study 1, 14 professional male rugby league players competed in an 80-minute competitive rugby league game. In Study 2 (in a randomized repeated measures design), 16 recreationally active males completed an exhaustive cycling protocol to deplete muscle glycogen followed by 36 hours of HIGH or LOW carbohydrate intake (8 v 3 g.kg body mass). In both studies, muscle biopsies and ultrasound scans were obtained from the vastus lateralis (at 50% of the muscle length) before and after match play in Study 1 and at 36 h after glycogen depletion in Study 2. RESULTS: Despite match play reducing (P0.05) were present between changes in muscle glycogen concentration and changes in ultrasound scores. CONCLUSION: Data demonstrate that ultrasound (as based on measures of pixilation intensity) is not valid to measure muscle glycogen status within the physiological range (i.e. 200-500 mmol.kg dw) that is applicable to exercise-induced muscle glycogen utilization and post-exercise muscle glycogen re-synthesis

    Muscle Glycogen Utilisation during an Australian Rules Football Game.

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    PURPOSE: To better understand the carbohydrate (CHO) requirement of Australian Football (AF) match play by quantifying muscle glycogen utilisation during an in-season AF match. METHODS: After a 24 h CHO loading protocol of 8 g/kg and 2 g/kg in the pre-match meal, two elite male forward players had biopsies sampled from m. vastus lateralis before and after participation in a South Australian Football League game. Player A (87.2kg) consumed water only during match play whereas player B (87.6kg) consumed 88 g CHO via CHO gels. External load was quantified using global positioning system technology. RESULTS: Player A completed more minutes on the ground (115 vs. 98 min) and covered greater total distance (12.2 vs. 11.2 km) than Player B, though with similar high-speed running (837 vs. 1070 m) and sprinting (135 vs. 138 m), respectively. Muscle glycogen decreased by 66% in Player A (Pre-: 656, Post-: 223 mmol∙kg-1 dw) and 24% in Player B (Pre-: 544, Post-: 416 mmol∙kg-1 dw), respectively. CONCLUSION: Pre-match CHO loading elevated muscle glycogen concentrations (i.e. >500 mmol.kg-1 dw), the magnitude of which appears sufficient to meet the metabolic demands of elite AF match play. The glycogen cost of AF match play may be greater than soccer and rugby and CHO feeding may also spare muscle glycogen use. Further studies using larger sample sizes are now required to quantify the inter-individual variability of glycogen cost of match play (including muscle and fibre-type specific responses) as well examine potential metabolic and ergogenic effects of CHO feeding

    The competent sentinel node: an association with an axillary presentation and an occult or a small primary invasive breast carcinoma

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    The concept of the sentinel node describes a primary or sentinel lymph node (SLN), which exists and through which tumour cells from a primary tumour in a particular location must first travel to spread to a particular regional lymph node group. In this series we present three patients presenting with a pathological axillary node associated with either an occult or very small primary breast cancer. In each case the primary tumour was found to have metastasised to the palpable node, however despite the significant enlargement of this node, no other axillary nodes were found to be affected on axillary node clearance. This has led us to postulate that the SLN in some cases contains unique characteristics that enable it to prevent further spread of the tumour up the lymphatic chain. Hence the term the competent sentinel node

    A survey of statistics in three UK general practice journal

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    Background Many medical specialities have reviewed the statistical content of their journals. To our knowledge this has not been done in general practice. Given the main role of a general practitioner as a diagnostician we thought it would be of interest to see whether the statistical methods reported reflect the diagnostic process. Methods Hand search of three UK journals of general practice namely the British Medical Journal (general practice section), British Journal of General Practice and Family Practice over a one-year period (1 January to 31 December 2000). Results A wide variety of statistical techniques were used. The most common methods included t-tests and Chi-squared tests. There were few articles reporting likelihood ratios and other useful diagnostic methods. There was evidence that the journals with the more thorough statistical review process reported a more complex and wider variety of statistical techniques. Conclusions The BMJ had a wider range and greater diversity of statistical methods than the other two journals. However, in all three journals there was a dearth of papers reflecting the diagnostic process. Across all three journals there were relatively few papers describing randomised controlled trials thus recognising the difficulty of implementing this design in general practice

    The influence of sentinel lymph node tumour burden on additional lymph node involvement and disease-free survival in cutaneous melanoma – a retrospective analysis of 392 cases

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    Twenty per cent of sentinel lymph node (SLN)-positive melanoma patients have positive non-SLN lymph nodes in completion lymph node dissection (CLND). We investigated SLN tumour load, non-sentinel positivity and disease-free survival (DFS) to assess whether certain patients could be spared CLND. Sentinel lymph node biopsy was performed on 392 patients between 1999 and 2005. Median observation period was 38.8 months. Sentinel lymph node tumour load did not predict non-SLN positivity: 30.8% of patients with SLN macrometastases (⩾2 mm) and 16.4% with micrometastases (⩽2 mm) had non-SLN positivity (P=0.09). Tumour recurrences after positive SLNs were more than twice as frequent for SLN macrometastases (51.3%) than for micrometastases (24.6%) (P=0.005). For patients with SLN micrometastases, the DFS analysis was worse (P=0.003) when comparing those with positive non-SLNs (60% recurrences) to those without (17.6% recurrences). This difference did not translate into significant differences in DFS: patients with SLN micrometastasis, either with (P=0.022) or without additional positive non-SLNs (P<0.0001), fared worse than patients with tumour-free SLNs. The 2-mm cutoff for SLN tumour load accurately predicts differences in DFS. Non-SLN positivity in CLND, however, cannot be predicted. Therefore, contrary to other studies, no recommendations concerning discontinuation of CLND based on SLN tumour load can be deduced
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