Sex-dependent effects of chronic exercise on cognitive flexibility but not hippocampal Bdnf in aging mice

Cognitive impairments associated with advanced age involve alterations in the hippocampus that changes to experience throughout life. The hippocampus is critical for cognitive flexibility involved with extinction and reinstatement of conditioned fear. It is widely accepted that regular exercise can be beneficial for hippocampal function. Therefore, we asked whether chronic voluntary exercise in middle-aged mice can improve extinction and/or reinstatement of conditioned fear compared to standard housing. Eight-month-old male and female C57Bl/6J mice had access to a running wheel or remained in standard housing until 11 months of age. Alongside control standard-housed young adult (3-month-old) mice, they received tone-footshock pairings, which were subsequently extinguished with tone-alone presentations the next day. Half of the mice then received a reminder in the form of a single footshock. Male and female 11-month-old mice housed in standard conditions exhibited impaired reinstatement compared to young adult mice. However, for males that had access to a running wheel from 8 months of age, the reminder treatment rescued reinstatement ability. This was not observed in females. Additionally, exercise during middle age in both sexes increased expression of Bdnf mRNA in the hippocampus, specifically exon 4 mRNA. These results show that, at least for males, physical exercise is beneficial for reducing age-related decline in cognitive abilities. Despite not affecting reinstatement, exercise also increased Bdnf gene expression in the female hippocampus, which could potentially benefit other forms of hippocampus-dependent cognition.

Influence of a rotating nozzle diaphragm on the characteristics of axial low-consumption turbines

Экспериментально исследуются различные компоновки турбинных ступеней с целью обеспечения многорежимности у осевых малорасходных турбин. Определено, что под многорежимностью понимается способность турбины поддерживать величину КПД неизменной, или с небольшими изменениями в достаточно широком диапазоне изменения внешних нагрузок. С новой точки зрения обращено внимание на то, что наиболее выраженными свойствами многорежимности обладают турбины в состав которых входит вращающийся сопловой аппарат. В этой связи рассмотрены авторские результаты экспериментальных исследований биротативных турбин с большим углом поворота потока и двух-ступенчатых осевых турбин с частичным облопачиванием рабочего колеса. Выявлено, у исследованных биротативных турбин свойство многорежимности проявляется при степени парциальности, близкой к единице и регулируется путем изменения соотношения частот вращения соплового аппарата и рабочего колеса. А у одновальных турбин с частичным облопачиванием рабочего колеса свойство многорежимности проявляется в широком диапазоне изменения степени расширения в турбине также при полном подводе рабочего тела. Various arrangements of turbine stages are experimentally investigated in order to ensure multiplicity of operating levels for axial low-consumption turbines. It has been determined that multiplicity is understood as the ability of a turbine to maintain the efficiency value unchanged, or with small changes in a fairly wide range of external loads. From a new point of view, attention is drawn to the fact that the most marked properties of operating levels multiplicity are relevant to the turbines which include a rotating nozzle diaphragm. In this regard, the author's results of experimental studies of birotative turbines with a large flow angle and two-stage axial turbines with partial blading of the running wheel are considered. It was revealed that in the investigated birotative turbines the property of multiplicity is manifested at a degree of partiality close to 1 and is regulated by changing the ratio of the rotation frequencies of the nozzle diaphragm and the running wheel. And in single-shaft turbines with partial blading of the running wheel, the multiplicity property is manifested in a wide range of changes in the degree of expansion in the turbine, also with full supply of the working fluid.

Interactive Effects of Enalapril Administration and Novel HIIT Wheel-Bed Training in Aged Rats

Introduction: Growing research suggests that aerobic high-intensity interval training (HIIT) improves cardiovascular function and physical performance compared with moderate intensity continuous training (MICT). However relatively few animal models of HIIT are available to inform about the benefits of this exercise—particularly among older animals. In addition, there is little evidence for how HIIT training interacts with adjuvant pharmacological therapies known to enhance the impact of MCIT in older individuals such as Angiotensin Converting Enzyme (ACE) Inhibitors.Purpose: The aim of the present study was to establish a HIIT protocol in aged rats based on forced running wheel-bed, and to subsequently (1) establish the feasibility of the HIIT protocol in a proof-of-concept study evaluating interactions between HIIT and (2) the result of combining HIIT + ACE inhibitor treatment using the ACE inhibitor enalapril.Methods: Two groups of rats were used in this study. The feasibility of using wheel-bed for HIIT training was tested in group one (15- and 30-month-old male rats). In the second group, 37 24-month-old Fisher 344 x Brown Norway male rats were randomly divided into four subgroups: control, enalapril, HIIT training group, and HIIT training combined with enalapril administration. The training and administration lasted for 4 weeks. After the intervention, locomotor activity, exercise tolerance, and grip strength were tested.Results: Our feasibility study suggested that middle-aged and aged rats were able to successfully complete the HIIT training. In our intervention study, HIIT training alone, regardless of adjuvant enalapril intervention, did raise treadmill exercise tolerance vs. the sedentary condition. Measures of healthspan were not negatively impacted by HIIT training.Conclusion: The novel HIIT protocol based on forced running wheel-bed was successfully employed in aged rats. We conclude that future studies should compare the results and of multi-modal intervention strategies which include both HIIT and MICT in combination with adjuvant therapies such as enalapril to improve exercise tolerance and other global indices of healthspan.

JUSTIFICATION OF THE STRUCTURE OF THE CRANE WHEEL WITH ELASTIC INSERT

The article considers the modernized design of the crane running wheel with anelastic insert.The purpose of the study is to substantiate the rational design of the running wheel onthe basis of determining the dynamic forces that occur when moving the truck and the crane bridge.Crane equipment is of great importance for the mechanization of lifting and transportoperations in various industries. Bridge cranes perform various lifting and transport operations.Installation and dismantling of equipment and machines. Also take part in the technologicalprocess of the metallurgical industry.The costs associated with the replacement and restoration of the running wheels are 15-17%of the cost of repairing the entire crane. At the same time more than 90% of crane wheels fail due towear of flanges.The main tasks for the diagnosis of crane wheels and rail tracks are usually solved duringscheduled maintenance by visual inspection of the wheel and rail and identify their wear. But thisdiagnostic tool does not quite satisfy the modern conditions of the cranes, namely, the compatiblecondition of the wheels and rails is not assessed, and it is impossible to carry out such controlconstantly during operation.Mechanisms for moving bridge cranes have several designs. The mechanism for moving thetruck, as a rule, has one drive, which transmits motion to the two drive wheels. The mechanisms ofmovement of the crane can be with the central and separate drive. The mechanisms of movement with the central drive can be with a low-speed transmission shaft, with a high-speed transmissionshaft and with a medium-speed transmission shaft.With this design, the gearbox shafts are connected to the drive wheel shaft by means of aclutch and a transmission shaft. This impairs the operation of the entire mechanism, because thepresence of the transmission shaft increases the complexity of the manufacture of the crane and itsweight and requires a very precise installation.To overcome these shortcomings, a separate drive of the end beams of the bridge is used.If the load on one of the support beams of the bridge is less than on the other, the enginespeed on this support increases and the support begins to run forward relative to the more loadedsupport. But the first engine begins to receive increased load, which is transmitted through themetal structure of the bridge and unloads the engine of the second support, due to which the speedof the first engine decreases and the speed of the second engine increases until they are equalized.Thus, in the process of moving the crane with a separate drive is the redistribution of loadbetween the two engines. Although the scheme of the mechanism with separate drives requires twoengines, two brakes and two gearboxes, it is the cheapest, light weight and easy to manufacture.The design of running wheels of cranes and crane carts should exclude a possibility ofderailment of wheels. To do this, the running wheels have two side flanges - flanges, which serve toguide the running wheels on the rails.The dynamic forces that arise when moving the trucks of cranes are quite large and cannot beignored when designing cranes. Most of all, they are manifested by wear of wheels and rails duringthe occurrence of distortions on the cranes.Thus, improving the performance and operational reliability of crane running wheels is avery important task of modern crane construction.The research technique is based on analytical methods of research of dynamic efforts in themechanism of movement of the truck of the bridge crane. The decision of three mass dynamicschemes of movement of the cargo cart is received.The analysis of the received decisions showed that at application of a running wheel with anelastic insert, dynamic factors at movement of the truck decreases. Dependences for determinationof dynamic forces which arise at movement of a running crane wheel taking into account rigidity ofan elastic ring which is inserted into a running wheel are received. The design and a technique ofcalculation of a running crane wheel with the vulcanized ring are offered.

Optimization research on arc height of running surface based on reducing partial wear of straddle-type monorail vehicle running wheel tire

This article proposes an ideal of reducing the partial wear of the running wheels by optimizing the arc height of the running surface to improve the wheel-rail contact state. To realize this idea, two kinds of concave and convex running surfaces were designed, the “running wheel-rail beam” finite element model of three kinds of rail surfaces of concave, convex, and plane were established. Taking the arc height of the running surface as the design variable, the total friction work and the friction work deviation (FWD) value as the dual optimization goal, an optimization model of arc height of running surface was established based on finite element model and multidisciplinary optimization platform Modefrontier. An improved genetic algorithm was used and an co-simulation optimization mode was put forward in the optimization. The optimization results show that when the concave height of the inner running surface is 22.62 mm, the total friction work and the FWD values are reduced by 11% and 11.8% respectively; When the convex height of the outer running surface is 11.81 mm, the objection values are reduced by 4.9% and 32.1% respectively. An ideal running surface was obtained and the life of the running wheel was extended by the research.

Use of running plates by floor housed rats: A pilot study

The outfit of husbandry facilities of, and the enrichment provided for, experimental rodents plays an important role in the animals’ welfare, and hence also for the societal acceptance of animal experiments. Whether rats and mice benefit from being provided with running wheels or plates is discussed controversially. Here we present observations from a feeding experiment, where rats were provided a running plate. As a pilot study, six identical cages, with three animals per cage, were filmed for six days, and the resulting footage was screened for the number of bouts and the time the animals spent on the plates. The main activities observed on the plate in descending order were sitting (18.5 ± 13.8 bouts or 8.0 ± 13.7 min/animal per day), standing (10.2 ± 11.6 bouts, 3.8 ± 4.2 min), running (8.2 ± 13.3 bouts, 10.1 ± 21.4 min), grooming (2.0 ± 2.8 bouts, 6.7 ± 25.7 min), sleeping (1.0 ± 2.6 bouts, 24.0 ± 61.8 min) and playing (0.5 ± 0.9 bouts, 0.1 ± 0.5 min). Most of these activities (91% of all bouts, 90% of total time) occurred at night, similar to previous studies on running wheel usage. The running plate seems well-accepted as cage enrichment, even though in further studies, the motivating triggers and the effects of long-term use could be evaluated more in-depth.

The Comparison of the Effects of Voluntary Running Wheel and Endurance Training on Il-6 and Testosterone Levels in the Rats With PCOS

Background and Aim: Polycystic Ovary Syndrome (PCOS) is an endocrine disorder in women of reproductive age. In cross-sectional and longitudinal studies, exercise training is an effective solution for treating and declining the symptoms. This study aims to compare the effects of the voluntary and the endurance exercise on some of the inflammatory and hormonal markers in rats with PCOS. Methods & Materials: In this study, Which was experimental and applied in terms of purpose, 40 female Wistar rats with Mean±SD weight of 220±20 g were divided randomly into four groups of ten: 1) control, 2) PCOS, 3) PCOS + Running wheel and 4) PCOS + endurance training. The rats in the voluntary group experienced voluntary activity of wheel running for 8 weeks (5 times a week). Alternatively, the endurance training group underwent aerobic exercises for 8 weeks (5 sessions in a week) on a treadmill. The blood samples were taken from the heart to measure the concentration of interleukin-6 and testosterone level and were analyzed by one-way analysis of variance and LSD post hoc test. Ethical Considerations: This study was approved by the Tehran University, Iran (Code: IR.UT.REC.1395016). Results: The results showed no significant difference in IL-6 and testosterone indices between endurance and voluntary training groups (P=0.565), (P=0.496). Both training groups (endurance and voluntary) separately resulted in a significant reduction in il6 and testosterone compared to rats with PCOS (P=0.002), (P=0.000), (P=0.038), (P=0.007). Conclusion: Altogether, the present study’s findings suggest that voluntary and endurance training in rats have similar effects on IL-6, Testosterone, and weight.

Pro-inflammatory Vascular Stress in Spontaneously Hypertensive Rats Associated With High Physical Activity Cannot Be Attenuated by Aldosterone Blockade

The effect of high physical activity, performed as voluntary running wheel exercise, on inflammation and vascular adaptation may differ between normotensive and spontaneously hypertensive rats (SHRs). We investigated the effects of running wheel activity on leukocyte mobilization, neutrophil migration into the vascular wall (aorta), and transcriptional adaptation of the vascular wall and compared and combined the effects of high physical activity with that of pharmacological treatment (aldosterone antagonist spironolactone). At the start of the 6th week of life, before hypertension became established in SHRs, rats were provided with a running wheel over a period of 10-months'. To investigate to what extent training-induced changes may underlie a possible regression, controls were also generated by removal of the running wheel for the last 4 months. Aldosterone blockade was achieved upon oral administration of Spironolactone in the corresponding treatment groups for the last 4 months. The number of circulating blood cells was quantified by FACS analysis of peripheral blood. mRNA expression of selected proteins was quantified by RT-PCR. Histology and confocal laser microscopy were used to monitor cell migration. Although voluntary running wheel exercise reduced the number of circulating neutrophils in normotensive rats, it rather increased it in SHRs. Furthermore, running wheel activity in SHRs but not normotensive rats increased the number of natural killer (NK)-cells. Except of the increased expression of plasminogen activator inhibitor (PAI)-1 and reduction of von Willebrand factor (vWF), running wheel activity exerted a different transcriptional response in the vascular tissue of normotensive and hypertensive rats, i.e., lack of reduction of the pro-inflammatory IL-6 in vessels from hypertensive rats. Spironolactone reduced the number of neutrophils; however, in co-presence with high physical activity this effect was blunted. In conclusion, although high physical activity has beneficial effects in normotensive rats, this does not predict similar beneficial effects in the concomitant presence of hypertension and care has to be taken on interactions between pharmacological approaches and high physical activity in hypertensives.

Sex Differences in Neurophysiological Changes Following Voluntary Exercise in Adolescent Rats

Background: Adolescence is a period of time characterized by the onset of puberty and is marked by cognitive and social developments and gross physical changes that can play a role in athletic performance. Sex differences are present with differences in body size, height, physiology and behavior which contribute to differences in athletic performance as well. Pre-clinical studies representing this active group are lacking.Methods: Acute and chronic effects of exercise were evaluated. Male and female adolescent rats were given voluntary access to a running wheel for 10 consecutive days. Running behavior (males and females) and estrous cycling (females only) were analyzed daily. A second group was given 10 days of voluntary access to a running wheel, then rested for 10 days to determine the long-term effects of exercise on the adolescent brain. Brain and muscle tissue were harvested at 10 and 20 day time points to understand exercise-dependent changes in mitochondrial activity and neuroplasticity. Animal cohorts were carried out at two different sites: University of California Los Angeles and Pepperdine University.Results: On average, running distance, intensity of run, and length of running bout increased for both male and female rats across the 10 days measured. Females ran significantly further and for longer intervals compared to males. Cortical and muscle expression of PGC1α showed similar levels at 10 days regardless of sex and exercise. There was a significant increase in expression at 20 days in all groups correlating with body size (p's < 0.05). Cortical and hippocampal levels of BDNF were similar across all groups, however, BDNF was significantly higher in exercised females at the acute compared to long-term time point.Discussion: Adolescent rats allowed 10 days of exercise show changes in physiologic function. There are sex differences in running behavior not impacted by sex hormones. These results are important to further our understanding of how exercise impacts the adolescent brain.