КОНТРОЛЬ ИСКРЕНИЯ КОНТАКТА «ЩЕТКА – КОЛЛЕКТОР» В МАШИНАХ ПОСТОЯННОГО ТОКА С ПОМОЩЬЮ ОПТОЭЛЕКТРОННОГО АНАЛИЗАТОРА ИСКРЕНИЯ

A «brush-commutator» contact is one of the factor that affects commutative properties and commutation. The paper presents a new method for estimation of a commutation. It is based not on the researchers’ experience but on the corresponding indicated values of a computer optoelectronic sparking analyzer. This analyzer permits to identify specific commutator sectors and its circuits at an inequality angle of every individual sector, rotation rate, time selection of measuring cycle, sparking estimation of separate commutator sectors and every sector of subsequent measuring cycle.  Одним из факторов влияния на коммутационные свойства и правильную коммутацию является контакт щеток с коллектором. Неправильный контакт вызывает искрение, приводящее к износу как коллектора, так и щеток, что свидетельствует о плохой коммутации

A 12,000 Year Record of Explosive Volcanism in the Siple Dome Ice Core, West Antarctica

Air mass trajectories in the Southern Hemisphere provide a mechanism for transport to and deposition of volcanic products on the Antarctic ice sheet from local volcanoes and from tropical and subtropical volcanic centers. This study extends the detailed record of Antarctic, South American, and equatorial volcanism over the last 12,000 years using continuous glaciochemical series developed from the Siple Dome A (SDMA) ice core, West Antarctica. The largest volcanic sulfate spike ( 280 mu g/L) occurs at 5881 B. C. E. Other large signals with unknown sources are observed around 325 B. C. E. ( 270 mu g/L) and 2818 B. C. E. ( 191 mu g/L). Ages of several large equatorial or Southern Hemisphere volcanic eruptions are synchronous with many sulfate peaks detected in the SDMA volcanic ice chemistry record. The microprobe fingerprinting\u27\u27 of glass shards in the SDMA core points to the following Antarctic volcanic centers as sources of tephra found in the SDMA core: Balenny Island, Pleiades, Mount Berlin, Mount Takahe, and Mount Melbourne as well as Mount Hudson and possibly Mount Burney volcanoes of South America. Identified volcanic sources provide an insight into the poorly resolved transport history of volcanic products from source volcanoes to the West Antarctic ice sheet

Spatial organization acts on cell signaling: how physical force contributes to the development of cancer

Cells constantly encounter physical forces and respond to neighbors and circulating factors by triggering intracellular signaling cascades that in turn affect their behavior. The mechanisms by which cells transduce mechanical signals to downstream biochemical changes are not well understood. In their work, Salaita and coworkers show that the spatial organization of cell surface receptors is crucial for mechanotransduction. Consequently, force modulation that disrupts the mechanochemical coupling may represent a critical step in cancerogenesis

Virtual environments as memory training devices in navigational tasks for older adults.

Cognitive training approaches using virtual environments (VEs) might counter age-related visuospatial memory decline and associated difficulties in wayfinding. However, the effects of the visual design of a VE in route learning are not fully understood. Therefore, we created a custom-designed VE optimized for route learning, with adjusted levels of realism and highlighted landmark locations (MixedVE). Herein we tested participants' route recall performance in identifying direction of turn at the intersection with this MixedVE against two baseline alternatives (AbstractVE, RealisticVE). An older vs. a younger group solved the tasks in two stages (immediate vs. delayed recall by one week). Our results demonstrate that the MixedVE facilitates better recall accuracy than the other two VEs for both age groups. Importantly, this pattern persists a week later. Additionally, our older participants were mostly overconfident in their route recall performance, but the MixedVE moderated this potentially detrimental overconfidence. Before the experiment, participants clearly preferred the RealisticVE, whereas after the experiment, most of the younger, and many of the older participants, preferred the MixedVE. Taken together, our findings provide insights into the importance of tailoring visualization design in route learning with VEs. Furthermore, we demonstrate the great potential of the MixedVE and by extension, of similar VEs as memory training devices for route learning, especially for older participants

Statistical Analysis of the Processes Controlling Choline and Ethanolamine Glycerophospholipid Molecular Species Composition

The regulation and maintenance of the cellular lipidome through biosynthetic, remodeling, and catabolic mechanisms are critical for biological homeostasis during development, health and disease. These complex mechanisms control the architectures of lipid molecular species, which have diverse yet highly regulated fatty acid chains at both the sn1 and sn2 positions. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) serve as the predominant biophysical scaffolds in membranes, acting as reservoirs for potent lipid signals and regulating numerous enzymatic processes. Here we report the first rigorous computational dissection of the mechanisms influencing PC and PE molecular architectures from high-throughput shotgun lipidomic data. Using novel statistical approaches, we have analyzed multidimensional mass spectrometry-based shotgun lipidomic data from developmental mouse heart and mature mouse heart, lung, brain, and liver tissues. We show that in PC and PE, sn1 and sn2 positions are largely independent, though for low abundance species regulatory processes may interact with both the sn1 and sn2 chain simultaneously, leading to cooperative effects. Chains with similar biochemical properties appear to be remodeled similarly. We also see that sn2 positions are more regulated than sn1, and that PC exhibits stronger cooperative effects than PE. A key aspect of our work is a novel statistically rigorous approach to determine cooperativity based on a modified Fisher's exact test using Markov Chain Monte Carlo sampling. This computational approach provides a novel tool for developing mechanistic insight into lipidomic regulation

Beneficial effects of reading aloud and solving simple arithmetic calculations (learning therapy) on a wide range of cognitive functions in the healthy elderly: study protocol for a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Almost all cognitive functions decline with age. Results of previous studies have shown that cognitive training related to everyday life (reading aloud and solving simple arithmetic calculations), namely learning therapy, can improve two cognitive function (executive functions and processing speed) in elderly people. However, it remains unclear whether learning therapy engenders improvement of various cognitive functions or not. We investigate the impact of learning therapy on various cognitive functions (executive functions, episodic memory, short-term memory, working memory, attention, reading ability, and processing speed) in healthy older adults.</p> <p>Methods</p> <p>We use a single-blinded intervention with two parallel groups (a learning therapy group and a waiting list control group). Testers are blind to the study hypothesis and the group membership of participants. Through an advertisement in local newspaper, 64 healthy older adults are recruited. They will be assigned randomly to a learning therapy group or a waiting list control group. In the learning therapy group, participants are required to perform two cognitive tasks for 6 months: reading Japanese aloud and solving simple calculations. The waiting list group does not participate in the intervention. The primary outcome measure is the Stroop test score: a measure of executive function. Secondary outcome measures are assessments including the following: verbal fluency task, logical memory, first and second names, digit span forward, digit span backward, Japanese reading test, digit cancellation task, digit symbol coding, and symbol search. We assess these outcome measures before and after the intervention.</p> <p>Discussion</p> <p>This report is the first study which investigates the beneficial effects of learning therapy on a wide range of cognitive functions of elderly people. Our study provides sufficient evidence of learning therapy effectiveness. Most cognitive functions, which are correlated strongly with daily life activities, decrease with age. These study results can elucidate effects of cognitive training on elderly people.</p> <p>Trial registration</p> <p>This trial was registered in The University Hospital Medical Information Network Clinical Trials Registry (No. <a href="http://www.clinicaltrials.gov/ct2/show/UMIN000006998">UMIN000006998</a>).</p

Clinically relevant mutations in the ABCG2 transporter uncovered by genetic analysis linked to erythrocyte membrane protein expression

The ABCG2 membrane protein is a key xeno- and endobiotic transporter, modulating the absorption and metabolism of pharmacological agents and causing multidrug resistance in cancer. ABCG2 is also involved in uric acid elimination and its impaired function is causative in gout. Analysis of ABCG2 expression in the erythrocyte membranes of healthy volunteers and gout patients showed an enrichment of lower expression levels in the patients. By genetic screening based on protein expression, we found a relatively frequent, novel ABCG2 mutation (ABCG2-M71V), which, according to cellular expression studies, causes reduced protein expression, although with preserved transporter capability. Molecular dynamics simulations indicated a stumbled dynamics of the mutant protein, while ABCG2-M71V expression in vitro could be corrected by therapeutically relevant small molecules. These results suggest that personalized medicine should consider this newly discovered ABCG2 mutation, and genetic analysis linked to protein expression provides a new tool to uncover clinically important mutations in membrane proteins. © 2018 The Author(s)

Cognitive and cognitive-motor interventions affecting physical functioning: A systematic review

Background Several types of cognitive or combined cognitive-motor intervention types that might influence physical functions have been proposed in the past: training of dual-tasking abilities, and improving cognitive function through behavioral interventions or the use of computer games. The objective of this systematic review was to examine the literature regarding the use of cognitive and cognitive-motor interventions to improve physical functioning in older adults or people with neurological impairments that are similar to cognitive impairments seen in aging. The aim was to identify potentially promising methods that might be used in future intervention type studies for older adults. Methods A systematic search was conducted for the Medline/Premedline, PsycINFO, CINAHL and EMBASE databases. The search was focused on older adults over the age of 65. To increase the number of articles for review, we also included those discussing adult patients with neurological impairments due to trauma, as these cognitive impairments are similar to those seen in the aging population. The search was restricted to English, German and French language literature without any limitation of publication date or restriction by study design. Cognitive or cognitive-motor interventions were defined as dual-tasking, virtual reality exercise, cognitive exercise, or a combination of these. Results 28 articles met our inclusion criteria. Three articles used an isolated cognitive rehabilitation intervention, seven articles used a dual-task intervention and 19 applied a computerized intervention. There is evidence to suggest that cognitive or motor-cognitive methods positively affects physical functioning, such as postural control, walking abilities and general functions of the upper and lower extremities, respectively. The majority of the included studies resulted in improvements of the assessed functional outcome measures. Conclusions The current evidence on the effectiveness of cognitive or motor-cognitive interventions to improve physical functioning in older adults or people with neurological impairments is limited. The heterogeneity of the studies published so far does not allow defining the training methodology with the greatest effectiveness. This review nevertheless provides important foundational information in order to encourage further development of novel cognitive or cognitive-motor interventions, preferably with a randomized control design. Future research that aims to examine the relation between improvements in cognitive skills and the translation to better performance on selected physical tasks should explicitly take the relation between the cognitive and physical skills into account.ISSN:1471-231

Increased expression of EphA7 correlates with adverse outcome in primary and recurrent glioblastoma multiforme patients

<p>Abstract</p> <p>Background</p> <p>Malignant gliomas are lethal cancers, highly dependent on angiogenesis and treatment options and prognosis still remain poor for patients with recurrent glioblastoma multiforme (GBM). Ephs and ephrins have many well-defined functions during embryonic development of central nervous system such as axon mapping, neural crest cell migration, hindbrain segmentation and synapse formation as well as physiological and abnormal angiogenesis. Accumulating evidence indicates that Eph and ephrins are frequently overexpressed in different tumor types including GBM. However, their role in tumorigenesis remains controversial, as both tumor growth promoter and suppressor potential have been ascribed to Eph and ephrins while the function of EphA7 in GBM pathogenesis remains largely unknown.</p> <p>Methods</p> <p>In this study, we investigated the immunohistochemical expression of EphA7 in a series of 32 primary and recurrent GBM and correlated it with clinical pathological parameters and patient outcome. In addition, intratumor microvascular density (MVD) was quantified by immunostaining for endothelial cell marker von Willebrand factor (vWF).</p> <p>Results</p> <p>Overexpression of EphA7 protein was predictive of the adverse outcome in GBM patients, independent of MVD expression (p = 0.02). Moreover, high density of MVD as well as higher EphA7 expression predicted the disease outcome more accurately than EphA7 variable alone (p = 0.01). There was no correlation between MVD and overall survival or recurrence-free survival (p > 0.05). However, a statistically significant correlation between lower MVD and tumor recurrence was observed (p = 0.003).</p> <p>Conclusion</p> <p>The immunohistochemical assessment of tissue EphA7 provides important prognostic information in GBM and would justify its use as surrogate marker to screen patients for tyrosine kinase inhibitor therapy.</p