5,899 research outputs found

    P5CS expression study in a new family with ALDH18A1-associated hereditary spastic paraplegia SPG9

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    In 2015\u20132016, we and others reported ALDH18A1 mutations causing dominant (SPG9A) or recessive (SPG9B) spastic paraplegia. In vitro production of the ALDH18A1 product, \u3941-pyrroline-5-carboxylate synthetase (P5CS), appeared necessary for cracking SPG9 disease-causing mechanisms. We now describe a baculovirus\u2013insect cell system that yields mgs of pure human P5CS and that has proven highly valuable with two novel P5CS mutations reported here in new SPG9B patients. We conclude that both mutations are disease-causing, that SPG9B associates with partial P5CS deficiency and that it is clinically more severe than SPG9A, as reflected in onset age, disability, cognitive status, growth, and dysmorphic traits

    Students benefit from developing their own emergency medicine OSCE stations: a comparative study using the matched-pair method

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    Background: Students can improve the learning process by developing their own multiple choice questions. If a similar effect occurred when creating OSCE (objective structured clinical examination) stations by themselves it could be beneficial to involve them in the development of OSCE stations. This study investigates the effect of students developing emergency medicine OSCE stations on their test performance. Method: In the 2011/12 winter semester, an emergency medicine OSCE was held for the first time at the Faculty of Medicine at the University of Leipzig. When preparing for the OSCE, 13 students (the intervention group) developed and tested emergency medicine examination stations as a learning experience. Their subsequent OSCE performance was compared to that of 13 other students (the control group), who were parallelized in terms of age, gender, semester and level of previous knowledge using the matched-pair method. In addition, both groups were compared to 20 students who tested the OSCE prior to regular emergency medicine training (test OSCE group). Results: There were no differences between the three groups regarding age (24.3 +/- 2.6; 24.2 +/- 3.4 and 24 +/- 2.3 years) or previous knowledge (29.3 +/- 3.4; 29.3 +/- 3.2 and 28.9 +/- 4.7 points in the multiple choice {[} MC] exam in emergency medicine). Merely the gender distribution differed (8 female and 5 male students in the intervention and control group vs. 3 males and 17 females in the test OSCE group). In the exam OSCE, participants in the intervention group scored 233.4 +/- 6.3 points (mean +/- SD) compared to 223.8 +/- 9.2 points (p < 0.01) in the control group. Cohen's effect size was d = 1.24. The students of the test OSCE group scored 223.2 +/- 13.4 points. Conclusions: Students who actively develop OSCE stations when preparing for an emergency medicine OSCE achieve better exam results

    Many-to-Many Information Flow Policies

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    Information flow techniques typically classify information according to suitable security levels and enforce policies that are based on binary relations between individual levels, e.g., stating that information is allowed to flow from one level to another. We argue that some information flow properties of interest naturally require coordination patterns that involve sets of security levels rather than individual levels: some secret information could be safely disclosed to a set of confidential channels of incomparable security levels, with individual leaks considered instead illegal; a group of competing agencies might agree to disclose their secrets, with individual disclosures being undesired, etc. Motivated by this we propose a simple language for expressing information flow policies where the usual admitted flow relation between individual security levels is replaced by a relation between sets of security levels, thus allowing to capture coordinated flows of information. The flow of information is expressed in terms of causal dependencies and the satisfaction of a policy is defined with respect to an event structure that is assumed to capture the causal structure of system computations. We suggest applications to secret exchange protocols, program security and security architectures, and discuss the relation to classic notions of information flow control

    Children and older adults exhibit distinct sub-optimal cost-benefit functions when preparing to move their eyes and hands

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    "© 2015 Gonzalez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited"Numerous activities require an individual to respond quickly to the correct stimulus. The provision of advance information allows response priming but heightened responses can cause errors (responding too early or reacting to the wrong stimulus). Thus, a balance is required between the online cognitive mechanisms (inhibitory and anticipatory) used to prepare and execute a motor response at the appropriate time. We investigated the use of advance information in 71 participants across four different age groups: (i) children, (ii) young adults, (iii) middle-aged adults, and (iv) older adults. We implemented 'cued' and 'non-cued' conditions to assess age-related changes in saccadic and touch responses to targets in three movement conditions: (a) Eyes only; (b) Hands only; (c) Eyes and Hand. Children made less saccade errors compared to young adults, but they also exhibited longer response times in cued versus non-cued conditions. In contrast, older adults showed faster responses in cued conditions but exhibited more errors. The results indicate that young adults (18 -25 years) achieve an optimal balance between anticipation and execution. In contrast, children show benefits (few errors) and costs (slow responses) of good inhibition when preparing a motor response based on advance information; whilst older adults show the benefits and costs associated with a prospective response strategy (i.e., good anticipation)

    Temporal Stability and the Effects of Training on Saccade Latency in “Express Saccade Makers”

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    The temporal stability of saccade latency, and the effects of training, particularly in “express saccade makers” (ESMs), has received little attention. ESMs are healthy, naïve, adults, who persist in executing very many low latency “express saccades” (ES; saccades with latency of 80 ms to 130 ms), in conditions designed to suppress such responses. We investigated the stability of ES production (%ES) in 59 ESM and 54 non-ESM participants in overlap tasks. Within a single session, the intraclass correlation coefficient (ICC) for %ES in two runs of 200 trials was 0.97 (p30% of saccades over the two runs were ES, were classified as ESMs. For 60 participants tested over two sessions 12 weeks apart, and 30 participants tested in three sessions over approximately six months, the ICC for %ES was uniformly high (0.95, p<0.001 and 0.97, p<0.001 respectively) and participants behaved consistently with their initial classification. Fourteen participants (7 ESMs) were then exposed to training consisting of either gap or overlap tasks. Training increased %ES in both groups. However, when tested in overlap tasks, it was not sufficient to transform Normal participants into ESMs. We conclude that the pattern of saccade behaviour exhibited by ESMs constitutes a stable and distinct oculomotor phenotype

    Answer changing in multiple choice assessment change that answer when in doubt – and spread the word!

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    <p>Abstract</p> <p>Background</p> <p>Several studies during the last decades have shown that answer changing in multiple choice examinations is generally beneficial for examinees. In spite of this the common misbelief still prevails that answer changing in multiple choice examinations results in an increased number of wrong answers rather than an improved score. One suggested consequence of newer studies is that examinees should be informed about this misbelief in the hope that this prejudice might be eradicated. This study aims to confirm data from previous studies about the benefits of answer changing as well as pursue the question of whether students informed about the said advantageous effects of answer changing would indeed follow this advice and change significantly more answers. Furthermore a look is cast on how the overall examination performance and mean point increase of these students is affected.</p> <p>Methods</p> <p>The answer sheets to the end of term exams of 79 3<sup>rd </sup>year medical students at the University of Munich were analysed to confirm the benefits of answer changing. Students taking the test were randomized into two groups. Prior to taking the test 41 students were informed about the benefits of changing answers after careful reconsideration while 38 students did not receive such information. Both groups were instructed to mark all answer changes made during the test.</p> <p>Results</p> <p>Answer changes were predominantly from wrong to right in full accordance with existing literature resources. It was shown that students who had been informed about the benefits of answer changing when in doubt changed answers significantly more often than students who had not been informed. Though students instructed on the benefits of changing answers scored higher in their exams than those not instructed, the difference in point increase was not significant.</p> <p>Conclusion</p> <p>Students should be informed about the benefits of changing initial answers to multiple choice questions once when in reasonable doubt about these answers. Furthermore, reconsidering answers should be encouraged as students will heed the advice and change more answers than students not so instructed.</p

    Spatially valid proprioceptive cues improve the detection of a visual stimulus

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    Vision and proprioception are the main sensory modalities that convey hand location and direction of movement. Fusion of these sensory signals into a single robust percept is now well documented. However, it is not known whether these modalities also interact in the spatial allocation of attention, which has been demonstrated for other modality pairings. The aim of this study was to test whether proprioceptive signals can spatially cue a visual target to improve its detection. Participants were instructed to use a planar manipulandum in a forward reaching action and determine during this movement whether a near-threshold visual target appeared at either of two lateral positions. The target presentation was followed by a masking stimulus, which made its possible location unambiguous, but not its presence. Proprioceptive cues were given by applying a brief lateral force to the participant’s arm, either in the same direction (validly cued) or in the opposite direction (invalidly cued) to the on-screen location of the mask. The dâ€Č detection rate of the target increased when the direction of proprioceptive stimulus was compatible with the location of the visual target compared to when it was incompatible. These results suggest that proprioception influences the allocation of attention in visual spac

    Far-infrared spectroscopic images of M83

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    We have mapped the nearby face on barred spiral galaxy, M83 in the bright [CII] 158 ÎŒm, [OI] 63 and 146 ÎŒm, [NII] 122 ÎŒm, and [OIII] 88 ÎŒm fine-structure lines with the Long Wavelength Spectrometer (LWS) on ISO. The maps are nearly fully sampled, and cover the inner 6.75' x 6' region - essentially the entire optical disk. We also obtained a full LWS grating scan of the nucleus. The lines are detectable over the entire disk, and enhanced at the nucleus, where the [OI] 63 ÎŒm and [NII] lines are particularly strong. At the nucleus, the line ratios indicate a strong starburst headed by O9 stars. Surprisingly, the [OI] and [CII] line emission (from photodissociation regions) is not enhanced relative to [NII] (from low density HII regions) on the spiral arms. The line ratios are the same for the spiral arms and interarm regions. We find very strong emission in the [OIII] 88 ÎŒm, [OI] 146 ÎŒm, and [CII] lines at the intersection of the bar and spiral arm to the SW indicating particularly strong star formation activity there. The [OI] 63 ÎŒm/146 ÎŒm line ratio is quite small there likely the result of self absorption in the 63 ÎŒm line by enveloping clouds. The total luminosity of this emission peak is 1.2 x 109 Lodo

    Copper Chaperone for Cu/Zn Superoxide Dismutase is a sensitive biomarker of mild copper deficiency induced by moderately high intakes of zinc

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    BACKGROUND: Small increases in zinc (Zn) consumption above recommended amounts have been shown to reduce copper (Cu) status in experimental animals and humans. Recently, we have reported that copper chaperone for Cu/Zn superoxide dismutase (CCS) protein level is increased in tissues of overtly Cu-deficient rats and proposed CCS as a novel biomarker of Cu status. METHODS: Weanling male Wistar rats were fed one of four diets normal in Cu and containing normal (30 mg Zn/kg diet) or moderately high (60, 120 or 240 mg Zn/kg diet) amounts of Zn for 5 weeks. To begin to examine the clinical relevance of CCS, we compared the sensitivity of CCS to mild Cu deficiency, induced by moderately high intakes of Zn, with conventional indices of Cu status. RESULTS: Liver and erythrocyte CCS expression was significantly (P < 0.05) increased in rats fed the Zn-60 and/or Zn-120 diet compared to rats fed normal levels of Zn (Zn-30). Erythrocyte CCS expression was the most sensitive measure of reduced Cu status and was able to detect a decrease in Cu nutriture in rats fed only twice the recommended amount of Zn. Liver, erythrocyte and white blood cell CCS expression showed a significant (P < 0.05) inverse correlation with plasma and liver Cu concentrations and caeruloplasmin activity. Unexpectedly, rats fed the highest level of Zn (Zn-240) showed overall better Cu status than rats fed a lower level of elevated Zn (Zn-120). Improved Cu status in these rats correlated with increased duodenal mRNA expression of several Zn-trafficking proteins (i.e. MT-1, ZnT-1, ZnT-2 and ZnT-4). CONCLUSION: Collectively, these data show that CCS is a sensitive measure of Zn-induced mild Cu deficiency and demonstrate a dose-dependent biphasic response for reduced Cu status by moderately high intakes of Zn
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