259 research outputs found

    How visual information influences dual-task driving and tracking

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    The study examined the impact of visual predictability on dual-task performance in driving and tracking tasks. Participants (N = 27) performed a simulated driving task and a pursuit tracking task. In either task, visual predictability was manipulated by systematically varying the amount of advance visual information: in the driving task, participants drove at night with low beam, at night with high beam, or in daylight; in the tracking task, participants saw a white line that specified the future target trajectory for 200, 400 or 800 ms. Concurrently with driving or tracking, participants performed an auditory task. They had to discriminate between two sounds and press a pedal upon hearing the higher sound. Results show that in general, visual predictability benefited driving and tracking; however, dual-task driving performance was best with highest visual predictability (daylight), dual-task tracking performance was best with medium visual predictability (400 ms). Braking/reaction times were higher in dual tasks compared to single tasks, but were unaffected by visual predictability, showing that its beneficial effects did not transfer to the auditory task. In both tasks, manual accuracy decreased around the moment the foot pressed the pedal, indicating interference between tasks. We, therefore, conclude that despite a general beneficial impact of predictability, the integration of visual information seems to be rather task specific, and that interference between driving and audiomotor tasks, and tracking and audiomotor tasks, seems comparable

    Пористая структура продуктов электрохимического синтеза на переменном токе нанодисперсных оксидов олова

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    Методами электронной микроскопии и низкотемпературной адсорбции азота изучена пористая структура продуктов электролиза металлического олова на переменном токе промышленной частоты. Установлено, что продукты синтеза характеризуются высокими значениями удельной площади поверхности и мезапористой структурой. Показано, что средний размер частиц варьирует в интервале 10…30 нм

    Physical activity monitoring in Alzheimer’s disease during sport interventions: a multi-methodological perspective

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    IntroductionAssessment methods for physical activity and fitness are of upmost importance due to the possible beneficial effect of physical conditioning on neurodegenerative diseases. The implementation of these methods can be challenging when examining elderly or cognitively impaired participants. In the presented study, we compared three different assessment methods for physical activity from the Dementia-MOVE trial, a 6-months intervention study on physical activity in Alzheimer’s disease. The aim was to determine the comparability of physical activity assessments in elderly participants with cognitive impairment due to Alzheimer’s disease.Material or methods38 participants (mean age 70 ± 7 years) with early-stage Alzheimer’s disease (mean MoCA 18.84 ± 4.87) were assessed with (1) fitness trackers for an average of 12 (± 6) days, (2) a written diary on daily activities and (3) a questionnaire on physical activity at three intervention timepoints. For comparison purposes, we present a transformation and harmonization method of the physical assessment output parameters: Metabolic equivalent of task (MET) scores, activity intensity minutes, calorie expenditure and moderate-to-vigorous physical activity (MVPA) scores were derived from all three modalities. The resulting parameters were compared for absolute differences, correlation, and their influence by possible mediating factors such as cognitive state and markers from cerebrospinal fluid.ResultsParticipants showed high acceptance and compliance to all three assessment methods. MET scores and MVPA from fitness trackers and diaries showed high overlap, whilst results from the questionnaire suggest that participants tended to overestimate their physical activity in the long-term retrospective assessment. All activity parameters were independent of the tested Alzheimer’s disease parameters, showing that not only fitness trackers, but also diaries can be successfully applied for physical activity assessment in a sample affected by early-stage Alzheimer’s disease.DiscussionOur results show that fitness trackers and physical activity diaries have the highest robustness, leading to a highly comparable estimation of physical activity in people with Alzheimer’s disease. As assessed parameters, it is recommendable to focus on MET, MVPA and on accelerometric sensor data such as step count, and less on activity calories and different activity intensities which are dependent on different variables and point to a lower reliability

    Nanoencapsulated capsaicin changes migration behavior and morphology of madin darby canine kidney cell monolayers

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    We have developed a drug delivery nanosystem based on chitosan and capsaicin. Both substances have a wide range of biological activities. We investigated the nanosystem’s influence on migration and morphology of Madin Darby canine kidney (MDCK-C7) epithelial cells in comparison to the capsaicin-free nanoformulation, free capsaicin, and control cells. For minimally-invasive quantification of cell migration, we applied label-free digital holographic microscopy (DHM) and single-cell tracking. Moreover, quantitative DHM phase images were used as novel stain-free assay to quantify the temporal course of global cellular morphology changes in confluent cell layers. Cytoskeleton alterations and tight junction protein redistributions were complementary analyzed by fluorescence microscopy. Calcium influx measurements were conducted to characterize the influence of the nanoformulations and capsaicin on ion channel activities. We found that both, capsaicin-loaded and unloaded chitosan nanocapsules, and also free capsaicin, have a significant impact on directed cell migration and cellular motility. Increase of velocity and directionality of cell migration correlates with changes in the cell layer surface roughness, tight junction integrity and cytoskeleton alterations. Calcium influx into cells occurred only after nanoformulation treatment but not upon addition of free capsaicin. Our results pave the way for further studies on the biological significance of these findings and potential biomedical applications, e.g. as drug and gene carriers

    Hippocampus specific iron deficiency alters competition and cooperation between developing memory systems

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    Iron deficiency (ID) is the most common gestational micronutrient deficiency in the world, targets the fetal hippocampus and striatum and results in long-term behavioral abnormalities. These structures primarily mediate spatial and procedural memory, respectively, in the rodent but have interconnections that result in competition or cooperation during cognitive tasks. We determined whether ID-induced impairment of one alters the function of the other by genetically inducing a 40% reduction of hippocampus iron content in late fetal life in mice and measuring dorsal striatal gene expression and metabolism and the behavioral balance between the two memory systems in adulthood. Slc11a2hipp/hipp mice had similar striatum iron content, but 18% lower glucose and 44% lower lactate levels, a 30% higher phosphocreatine:creatine ratio, and reduced iron transporter gene expression compared to wild type (WT) littermates, implying reduced striatal metabolic function. Slc11a2hipp/hipp mice had longer mean escape times on a cued task paradigm implying impaired procedural memory. Nevertheless, when hippocampal and striatal memory systems were placed in competition using a Morris Water Maze task that alternates spatial navigation and visual cued responses during training, and forces a choice between hippocampal and striatal strategies during probe trials, Slc11a2hipp/hipp mice used the hippocampus-dependent response less often (25%) and the visual cued response more often (75%) compared to WT littermates that used both strategies approximately equally. Hippocampal ID not only reduces spatial recognition memory performance but also affects systems that support procedural memory, suggesting an altered balance between memory systems

    Male mating biology

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    Before sterile mass-reared mosquitoes are released in an attempt to control local populations, many facets of male mating biology need to be elucidated. Large knowledge gaps exist in how both sexes meet in space and time, the correlation of male size and mating success and in which arenas matings are successful. Previous failures in mosquito sterile insect technique (SIT) projects have been linked to poor knowledge of local mating behaviours or the selection of deleterious phenotypes during colonisation and long-term mass rearing. Careful selection of mating characteristics must be combined with intensive field trials to ensure phenotypic characters are not antagonistic to longevity, dispersal, or mating behaviours in released males. Success has been achieved, even when colonised vectors were less competitive, due in part to extensive field trials to ensure mating compatibility and effective dispersal. The study of male mating biology in other dipterans has improved the success of operational SIT programmes. Contributing factors include inter-sexual selection, pheromone based attraction, the ability to detect alterations in local mating behaviours, and the effects of long-term colonisation on mating competitiveness. Although great strides have been made in other SIT programmes, this knowledge may not be germane to anophelines, and this has led to a recent increase in research in this area

    Conditioning Individual Mosquitoes to an Odor: Sex, Source, and Time

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    Olfactory conditioning of mosquitoes may have important implications for vector-pathogen-host dynamics. If mosquitoes learn about specific host attributes associated with pathogen infection, it may help to explain the heterogeneity of biting and disease patterns observed in the field. Sugar-feeding is a requirement for survival in both male and female mosquitoes. It provides a starting point for learning research in mosquitoes that avoids the confounding factors associated with the observer being a potential blood-host and has the capability to address certain areas of close-range mosquito learning behavior that have not previously been described. This study was designed to investigate the ability of the southern house mosquito, Culex quinquefasciatus Say to associate odor with a sugar-meal with emphasis on important experimental considerations of mosquito age (1.2 d old and 3–5 d old), sex (male and female), source (laboratory and wild), and the time between conditioning and testing (<5 min, 1 hr, 2.5 hr, 5 hr, 10 hr, and 24 hr). Mosquitoes were individually conditioned to an odor across these different experimental conditions. Details of the conditioning protocol are presented as well as the use of binary logistic regression to analyze the complex dataset generated from this experimental design. The results suggest that each of the experimental factors may be important in different ways. Both the source of the mosquitoes and sex of the mosquitoes had significant effects on conditioned responses. The largest effect on conditioning was observed in the lack of positive response following conditioning for females aged 3–5 d derived from a long established colony. Overall, this study provides a method for conditioning experiments involving individual mosquitoes at close range and provides for future discussion of the relevance and broader questions that can be asked of olfactory conditioning in mosquitoes

    The HELLP syndrome: Clinical issues and management. A Review

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    <p>Abstract</p> <p>Background</p> <p>The HELLP syndrome is a serious complication in pregnancy characterized by haemolysis, elevated liver enzymes and low platelet count occurring in 0.5 to 0.9% of all pregnancies and in 10–20% of cases with severe preeclampsia. The present review highlights occurrence, diagnosis, complications, surveillance, corticosteroid treatment, mode of delivery and risk of recurrence.</p> <p>Methods</p> <p>Clinical reports and reviews published between 2000 and 2008 were screened using Pub Med and Cochrane databases.</p> <p>Results and conclusion</p> <p>About 70% of the cases develop before delivery, the majority between the 27th and 37th gestational weeks; the remainder within 48 hours after delivery. The HELLP syndrome may be complete or incomplete. In the Tennessee Classification System diagnostic criteria for HELLP are haemolysis with increased LDH (> 600 U/L), AST (≥ 70 U/L), and platelets < 100·10<sup>9</sup>/L. The Mississippi Triple-class HELLP System further classifies the disorder by the nadir platelet counts. The syndrome is a progressive condition and serious complications are frequent. Conservative treatment (≥ 48 hours) is controversial but may be considered in selected cases < 34 weeks' gestation. Delivery is indicated if the HELLP syndrome occurs after the 34th gestational week or the foetal and/or maternal conditions deteriorate. Vaginal delivery is preferable. If the cervix is unfavourable, it is reasonable to induce cervical ripening and then labour. In gestational ages between 24 and 34 weeks most authors prefer a single course of corticosteroid therapy for foetal lung maturation, either 2 doses of 12 mg betamethasone 24 hours apart or 6 mg or dexamethasone 12 hours apart before delivery. Standard corticosteroid treatment is, however, of uncertain clinical value in the maternal HELLP syndrome. High-dose treatment and repeated doses should be avoided for fear of long-term adverse effects on the foetal brain. Before 34 weeks' gestation, delivery should be performed if the maternal condition worsens or signs of intrauterine foetal distress occur. Blood pressure should be kept below 155/105 mmHg. Close surveillance of the mother should be continued for at least 48 hours after delivery.</p
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