569 research outputs found

    Predicting individual susceptibility to Visually Induced Motion Sickness (VIMS) by Questionnaire

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    BACKGROUND The introduction of new visual technologies increases the risk of visually induced motion sickness (VIMS). The aim was to evaluate the 6-item Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ; also known as the VIMSSQ-short) and other predictors for individual susceptibility to VIMS. METHODS Healthy participants (10M+20F), mean age 22.9 (SD 5.0) years, viewed a 360Ā° panoramic city scene projected in the visual equivalent to the situation of rotating about an axis tilted from the vertical. The scene rotated at 0.2Hz (72Ā° s-1), with a ā€˜wobbleā€™ produced by superimposed 18Ā° tilt on the rotational axis, with a field of view of 83.5Ā°. Exposure was 10 min or until moderate nausea was reported. Simulator Sickness Questionnaire (SSQ) was the index of VIMS. Predictors/correlates were VIMSSQ, Motion Sickness Susceptibility Questionnaire (MSSQ), Migraine (scale), Syncope, Social & Work Impact of Dizziness (SWID), Sleep quality/disturbance, Personality (ā€˜Big Fiveā€™ TIPI), a prior multisensory Stepping-Vection test, and Vection during exposure. RESULTS The VIMSSQ had good scale reliability (Cronbachā€™s alpha=0.84). and correlated significantly with the SSQ (r=0.58). Higher MSSQ, Migraine, Syncope & SWID also correlated significantly with SSQ. Other variables had no significant relationships with SSQ. Regression models showed that the VIMSSQ predicted 34% of the individual variation of VIMS, increasing to 56% as MSSQ, Migraine, Syncope and SWID were incorporated as additional predictors. CONCLUSIONS The VIMSSQ is a useful adjunct to the MSSQ in predicting VIMS. Other predictors included Migraine, Syncope & SWID. No significant relationship was observed between Vection and VIMS

    Measuring the susceptibility to visually induced motion sickness and its relationship with vertigo, dizziness, migraine, syncope and personality traits

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    BACKGROUND: The widespread use of visual technologies such as Virtual Reality increases the risk of visually induced motion sickness (VIMS). Previously, the 6-item short version of the Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ short form) has been validated for predicting individual variation in VIMS. The aim of the current study was to investigate how the susceptibility to VIMS is correlated with other relevant factors in the general population. METHODS: A total of 440 participants (201M, 239F), mean age 33.6 (SD 14.8) years, completed an anonymous online survey of various questionnaires including the VIMSSQ, Motion Sickness Susceptibility Questionnaire (MSSQ), Vertigo in City questionnaire (VIC), Migraine (scale), Social & Work Impact of Dizziness (SWID), Syncope (faintness), and Personality (ā€˜Big Fiveā€™ TIPI). RESULTS: The VIMSSQ correlated positively with the MSSQ (r = .50), VIC (r = .45), Migraine (r = .44), SWID (r = .28), and Syncope (r = .15). The most efficient Multiple Linear Regression model for the VIMSSQ included the predictors MSSQ, Migraine, VIC, and Age and explained 40% of the variance. Factor analysis of strongest correlates with VIMSSQ revealed a single factor loading with VIMSSQ, MSSQ, VIC, Migraine, SWID, and Syncope, suggesting a common latent variable of sensitivity. CONCLUSIONS: The set of predictors for the VIMSSQ in the general population has similarity with those often observed in patients with vestibular disorders. Based on these correlational results, we suggest the existence of continuum of underlying risk factors for sensitivity, from healthy population to patients with extreme visual vertigo and perhaps Persistent Postural-Perceptual Dizziness

    The Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ): Estimating Individual Susceptibility to Motion Sickness-Like Symptoms When Using Visual Devices

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    Objective Two studies were conducted to develop and validate a questionnaire to estimate individual susceptibility to visually induced motion sickness (VIMS). Background VIMS is a common side-effect when watching dynamic visual content from various sources, such as virtual reality, movie theaters, or smartphones. A reliable questionnaire predicting individual susceptibility to VIMS is currently missing. The aim was to fill this gap by introducing the Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ). Methods A survey and an experimental study were conducted. Survey: The VIMSSQ investigated the frequency of nausea, headache, dizziness, fatigue, and eyestrain when using different visual devices. Data were collected from a survey of 322 participants for the VIMSSQ and other related phenomena such as migraine. Experimental study: 23 participants were exposed to a VIMS-inducing visual stimulus. Participants filled out the VIMSSQ together with other questionnaires and rated their level of VIMS using the Simulator Sickness Questionnaire (SSQ). Results Survey: The most prominent symptom when using visual devices was eyestrain, and females reported more VIMS than males. A one-factor solution with good scale reliability was found for the VIMSSQ. Experimental study: Regression analyses suggested that the VIMSSQ can be useful in predicting VIMS (R2 = .34) as measured by the SSQ, particularly when combined with questions pertaining to the tendency to avoid visual displays and experience syncope (R2 = .59). Conclusion We generated normative data for the VIMSSQ and demonstrated its validity. Application The VIMSSQ can become a valuable tool to estimate oneā€™s susceptibility to VIMS based on self-reports

    Magnetic properties of Ruddlesden-Popper phases Sr3āˆ’x_{3-x}Yx_{x}(Fe1.25_{1.25}Ni0.75_{0.75})O7āˆ’Ī“_{7-\delta}: A combined experimental and theoretical investigation

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    We present a comprehensive study of the magnetic properties of Sr3āˆ’x_{3-x}Yx_{x}(Fe1.25_{1.25}Ni0.75_{0.75})O7āˆ’Ī“_{7-\delta} (0ā‰¤xā‰¤0.750 \leq x \leq 0.75). Experimentally, the magnetic properties are investigated using superconducting quantum interference device (SQUID) magnetometry and neutron powder diffraction (NPD). This is complemented by the theoretical study based on density functional theory as well as the Heisenberg exchange parameters. Experimental results show an increase in the N\'eel temperature (TNT_N) with the increase of Y concentrations and O occupancy. The NPD data reveals all samples are antiferromagnetically ordered at low temperatures, which has been confirmed by our theoretical simulations for the selected samples. Our first-principles calculations suggest that the 3D magnetic order is stabilized due to finite inter-layer exchange couplings. The latter give rise to a finite inter-layer spin correlations which disappear above the TNT_N

    High throughput automated microbial bioreactor system used for clone selection and rapid scale-down process optimization

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    High throughput automated fermentation systems have become a useful tool in early bioprocess development. In this study, we investigated a 24 x 15 mL single use microbioreactor system, ambr 15f, designed for microbial culture. We compared the fed-batch growth and production capabilities of this system for two Escherichia coli strains, BL21 (DE3) and MC4100, and two industrially relevant molecules, hGH and scFv. In addition, different carbon sources were tested using bolus, linear or exponential feeding strategies, showing the capacity of the ambr 15f system to handle automated feeding. We used power per unit volume (P/V) as a scale criterion to compare the ambr 15f with 1 L stirred bioreactors which were previously scaled-up to 20 L with a different biological system, thus showing a potential 1,300 fold scale comparability in terms of both growth and product yield. By exposing the cells grown in the ambr 15f system to a level of shear expected in an industrial centrifuge, we determined that the cells are as robust as those from a bench scale bioreactor. These results provide evidence that the ambr 15f system is an efficient high throughput microbial system that can be used for strain and molecule selection as well as rapid scale-up. Ā© 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 2017

    OZM Ball Drop Impact Tester (BITā€132) vs. BAM Standard Method ā€“ a Comparative Investigation

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    Safety, performance, cost efficient synthesis and toxicity are the most important aspects of modern explosives. Sensitivity measurements are performed in accordance with different protocols all around the world. Sometimes the BAM drop hammer does not accurately reflect the sensitivity of an energetic material, in particular the sensitivity of primary explosives. Therefore, we present here preliminary results obtained using the novel ball drop tester (BITā€132), manufactured by OZM research, following MILā€STDā€1751ā€…A (method 1016). The ball drop impact sensitivity tester is a device in which a freeā€falling steel ball is dropped onto an unconfined sample, and is expected to produce more realistic results than the currently commonly used BAM method. The results obtained using the probit analysis were compared to those from the BAM drop hammer and friction tester. The following sensitive explosives were investigated: HMTD, TATP, TAT, Tetrazene, MTXā€1, KDNBF, KDNP, K2DNABT, Lead Styphnate Monohydrate, DBXā€1, Nickel(II) Hydrazine Nitrate, Silver Acetylide, AgN3, Pb(N3)2 RDā€1333, AgCNO, and Hg(CNO)2

    Epidemiological Aspects of Visceral Leishmaniasis in Baft District, Kerman Province, Southeast of Iran

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    Background: Visceral leishmaniasis (kala-azar) is an endemic disease in some areas of Iran. A cross- sectional study was conducted for sero-epidemiological survey of visceral leishmaniasis (VL) in Baft district from Kerman Province, southeast of Iran.Methods: Blood samples were collected from children up to 12 years old and 10% of adult population from Baft villages with a multi-stage randomized cluster sampling. In addition, blood samples were collected from 30 domestic dogs from the same areas. All the collected blood samĀ­ples were tested by direct agglutination test (DAT) for the detection of anti-Leishmania antibodĀ­ies in both human and dog using the cut-off value of ā‰„1:3200 and ā‰„ 1:320, respectively. ParasitologiĀ­cal, molecular, and pathological were performed on infected dogs. Chi-square and Fisher exact tests were used to compare sero-prevalence values.Results: From 1476 collected human serum samples, 23 (1.55%) showed anti-Leishmania antibodĀ­ies at titers of 1:800 and 1:1600 whereas 14 (0.95%) showed anti-Leishmania infantum antibodies at titers of ā‰¤ 1:3200. No statistically significant difference was found between male (1.18 %) and female (0.69%) sero-prevalence (P=0.330). Children of 5-8 years showed the highĀ­est sero-prevalence rate (3.22%). Seven out of 30 domestic dogs (23%) showed anti-Leishmania antibodies at titers ā‰¤1:320. Leishmania infantum was identified in five infected dogs by nested - PCR assay.Conclusion: It seems that visceral leishmaniasis is being endemic in southern villages of Baft district, southeast of Iran

    Association between vitamin A and E and apolipoprotein A and B levels in type 2 diabetes

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    Objective. To determine the relationship between serum vitamin A and E and apolipoprotein levels in type 2 diabetic patients. Setting. Shariati Hospital, Tehran, Iran. Subjects and methods. One hundred and seventeen eligible type 2 diabetic patients who attended the Endocrine Research and Metabolism Center between 2002 and 2004 were enrolled in the study. Blood samples were collected after a 12 - 14-hour overnight fast for the measurement of serum levels of total cholesterol, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein (apo) A1 and apoB, and vitamins A and E. Anthropometric indices were determined by physical examination. Data were analysed statistically using Pearson's coefficient, multiple regression, and partial and bivariate correlations. Results. The mean body mass index (BMI) of the subjects was 27.4 Ā± 3.7 kg/m2. The mean (Ā± standard deviation (SD)) serum levels of vitamins A and E were 0.5 Ā± 0.1 &#956;g/ml and 9.5 Ā± 2.6 &#956;g/ml, respectively. There were no significant differences in the plasma levels of vitamins A and E in males and females. Mean serum levels of vitamins A and E were within the normal range for both sexes. Serum lipid levels (total cholesterol, triglyceride and apoB) correlated with serum levels of vitamin E (p < 0.05). Serum levels of vitamins A and E were also correlated (p < 0.05). Standardised vitamin E levels showed significant negative correlation with most studied lipid profiles (p < 0.05). Conclusion. This study found that mean serum levels of the natural antioxidants vitamin E, and especially vitamin A, were close to the lower end of the normal range of these antioxidants in type 2 diabetics. Also, serum vitamin E and standardised vitamin E levels were important predictors of serum apoA1 levels in these patients. South African Journal of Clinical Nutrition Vol. 19(1) 2006: 39-4

    The Second to Fourth Digit Ratio in Elite and Non-Elite Greco-Roman Wrestlers

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    A low second-to-fourth digit ratio (2D:4D) has been reported to correlate with high performance and athletic potential of an individual in sport. It has been suggested that 2D:4D is a relatively weak predictor of strength and a stronger predictor of efficiency in aerobic exercise. Comparing extreme groups on a continuum of sports performance requiring high power (physical strength) output would be helpful to resolve this issue. Therefore, the purpose of the present study was to compare the 2D:4D ratio of world-class elite Greco-Roman wrestlers (n = 10) taking part in Olympic fitness camps in 2013 with the 2D:4D ratio of non-elite collegiate wrestlers (n = 20), and age-matched sedentary males (n = 40). The 2D:4D ratios of elite wrestlers were lower compared to non-elite athletes (p < 0.01, right hand d = 1.70, left hand d = 1.67) and the control group (p < 0.0001, right hand d = 3.16, left hand d = 2.00). No significant differences were noted among the groups for right - left 2D:4D. We concluded that 2D:4D may discriminate between non-elite and world-class wrestlers. We also suggest that a low 2D:4D ratio could be linked to performance potential in wrestlers. As such, 2D:4D may provide additional information, which is valuable in determining the potential athleticism of an individual, when it is used in conjunction with other measures. ƂĀ© 2017 Editorial Committee of Journal of Human Kinetics 2017
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