515 research outputs found
THE EFFECT OF INTERMITTENT THETA BURST STIMULATION ON BICEPS CORTICOMOTOR EXCITABILITY IN NON-IMPAIRED INDIVIDUALS AND INDIVIDUALS WITH TETRAPLEGIA
Neuromodulation of the primary motor cortex (M1) in pair with physical therapy may be a promising method for improving motor outcomes after spinal cord injury (SCI). Increased excitability of the corticospinal motor pathways (i.e. corticomotor excitability) has shown to be associated with improved motor learning and skill acquisition. Intermittent theta burst stimulation (iTBS) is a form of non-invasive brain stimulation which can increase corticomotor excitability, as measured by an increase in the amplitude of motor evoked potentials (MEPs). However, the ability for iTBS to increase the corticomotor excitability of proximal muscles such as the biceps, and muscles affected by spinal cord injury is currently unclear. Therefore, the purpose of the present studies was to determine the effect of iTBS on the corticomotor excitability of the biceps, as measured by MEP amplitudes, in non-impaired individuals and individuals with tetraplegia. Participants completed three sessions of the protocol, each including sham and active iTBS. Sessions were separated by a minimum of three days to prevent the potential for carry over effects. Results showed no change in nMEP amplitude after either sham or active iTBS in the non-impaired group. However, the SCI group showed an increase in nMEP amplitude after active iTBS relative to sham, suggesting an increase in corticomotor excitability. While further research is needed before combinatorial therapies can be achieved, this study suggests that iTBS may be a promising method for improving motor function in those with tetraplegia
Comparison of spool radial grooves influence between water and oil hydraulics
In this paper numerical flow calculations with respect to the annular gaps with added radial grooves normaly used on the spools of directional control valves were carried out. The impact of various annular gap geometries and radial grooves during variable pressure conditions, and while using different hydraulic fluids, on the flows through annular gaps were investigated for different flow regimes. Samples with different geometries and numbers of radial groves on the spool of the directional control valve were also made for the purpose of carrying out flow measurements. The two different hydraulic fluids that were used in the numerical simulations and for the flow measurements were a hydraulic mineral oil and tap water. The results of the numerical calculations for the different models of the radial grooves with axially symmetric geometries show their impact on the internal leakage with respect to three different regimes of flow. The results of the numerical calculations based on the use of a hydraulic oil show a trend that was established by the experimental investigation
Oscillations of cylinder piston rod – comparison of amplitudes and frequencies for the transient phenomena in tap water- and oil-based PCHS
Power-control hydraulic system (PCHS), as a part of a machine or production line, provides it with all or most of the necessary movements. Most of the movements in PCHS are carried out by means of hydraulic cylinders. In this case movements are mostly generated by cylinder piston rods. More or less obvious transient phenomena occur during these movements under conditions of acceleration and deceleration. As a consequence, oscillations are induced in the system. In our work we investigate the phenomena and parameters of such PCHS for two hydraulic fluids. Most of the PCHSs still use mineral oil as hydraulic fluid but it is environmentally very harmful. Ecological awareness during natural disasters and man-made pollution is the subject of much discussion. It is everybody’s responsibility to take care of the natural environment and reduce the threats to our future existence. The preservation of drinking water and the prevention of its contamination by pollution are particularly important. Powercontrol hydraulics is one important area in which a positive step could be made to protect the resources of drinking water. The use of tap water instead of the conventional hydraulic fluids in power-control hydraulics is one of the most environmentally friendly changes that could be implemented. Therefore in this paper we show, based on dynamic-transient parameters, both the functionality and the usability of water hydraulics in comparison to the more familiar oil hydraulics. A comparison of the dynamic behavior between the conventional oil and the relatively new water hydraulics under the same conditions is described. Mineral hydraulic oil was used in the oil hydraulic test rig and distilled water was used in the water hydraulic test rig. The tests were conducted at different flow rates (11, 22 and 33 lpm) and system pressures (70, 110 and 160 bar) as well as applying different loading conditions (first, with a mass of 163 kg in the horizontal and vertical positions and, second, without the mass). The registered amplitudes of the cylinder piston rod oscillations were 20-30 % smaller in the water hydraulics with respect to the case of oil hydraulics, while the frequencies of the piston rod oscillations were 7-20 % higher
Determination of reference genes for circadian studies in different tissues and mouse strains
<p>Abstract</p> <p>Background</p> <p>Circadian rhythms have a profound effect on human health. Their disruption can lead to serious pathologies, such as cancer and obesity. Gene expression studies in these pathologies are often studied in different mouse strains by quantitative real time polymerase chain reaction (qPCR). Selection of reference genes is a crucial step of qPCR experiments. Recent studies show that reference gene stability can vary between species and tissues, but none has taken circadian experiments into consideration.</p> <p>Results</p> <p>In the present study the expression of ten candidate reference genes (<it>Actb</it>, <it>Eif2a</it>, <it>Gapdh</it>, <it>Hmbs</it>, <it>Hprt1</it>, <it>Ppib</it>, <it>Rn18s</it>, <it>Rplp0</it>, <it>Tbcc </it>and <it>Utp6c</it>) was measured in 131 liver and 97 adrenal gland samples taken from three mouse strains (C57BL/6JOlaHsd, 129Pas plus C57BL/6J and <it>Crem </it>KO on 129Pas plus C57BL/6J background) every 4 h in a 24 h period. Expression stability was evaluated by geNorm and NormFinder programs. Differences in ranking of the most stable reference genes were observed both between individual mouse strains as well as between tissues within each mouse strain. We show that selection of reference gene (<it>Actb</it>) that is often used for analyses in individual mouse strains leads to errors if used for normalization when different mouse strains are compared. We identified alternative reference genes that are stable in these comparisons.</p> <p>Conclusions</p> <p>Genetic background and circadian time influence the expression stability of reference genes. Differences between mouse strains and tissues should be taken into consideration to avoid false interpretations. We show that the use of a single reference gene can lead to false biological conclusions. This manuscript provides a useful reference point for researchers that search for stable reference genes in the field of circadian biology.</p
Novel Insights into the Downstream Pathways and Targets Controlled by Transcription Factors CREM in the Testis
The essential role of the Crem gene in normal sperm development is widely accepted and is confirmed by azoospermia in male mice lacking the Crem gene. The exact number of genes affected by Crem absence is not known, however a large difference has been observed recently between the estimated number of differentially expressed genes found in Crem knock-out (KO) mice compared to the number of gene loci bound by CREM. We therefore re-examined global gene expression in male mice lacking the Crem gene using whole genome transcriptome analysis with Affymetrix microarrays and compared the lists of differentially expressed genes from Crem−/− mice to a dataset of genes where binding of CREM was determined by Chip-seq. We determined the global effect of CREM on spermatogenesis as well as distinguished between primary and secondary effects of the CREM absence. We demonstrated that the absence of Crem deregulates over 4700 genes in KO testis. Among them are 101 genes associated with spermatogenesis 41 of which are bound by CREM and are deregulated in Crem KO testis. Absence of several of these genes in mouse models has proven their importance for normal spermatogenesis and male fertility. Our study showed that the absence of Crem plays a more important role on different aspects of spermatogenesis as estimated previously, with its impact ranging from apoptosis induction to deregulation of major circadian clock genes, steroidogenesis and the cell-cell junction dynamics. Several new genes important for normal spermatogenesis and fertility are down-regulated in KO testis and are therefore possible novel targets of CREM
Expression of activin subunits and receptors in the developing human ovary:activin A promotes germ cell survival and proliferation before primordial follicle formation
Regulation of 3β-Hydroxysteroid Dehydrogenase/∆5-∆4 Isomerase: A Review
This review focuses on the expression and regulation of 3β-hydroxysteroi ddehydrogenase/Δ5-Δ4 isomerase (3β-HSD), with emphasis on the porcine version. 3β-HSD is often associated with steroidogenesis, but its function in the metabolism of both steroids and xenobiotics is more obscure. Based on currently available literature covering humans,rodents and pigs, this review provides an overview of the present knowledge concerning the regulatory mechanisms for 3β-HSD at all omic levels. The HSD isoenzymes are essential in steroid hormone metabolism, both in the synthesis and degradation of steroids.
They display tissue-specific expression and factors influencing their activity, which therefore indicates their tissue-specific responses. 3β-HSD is involved in the synthesis of a number of natural steroid hormones, including progesterone and testosterone, and the hepatic degradation of the pheromone androstenone. In general, a number of signaling and regulatory pathways have been demonstrated to influence 3β-HSD transcription and activity, e.g., JAK-STAT, LH/hCG, ERα, AR, SF-1 and PPARα. The expression and enzymic activity of 3β-HSD are also influenced by external factors, such as dietary composition. Much of the research conducted on porcine 3β-HSD is motivated by its importance for the occurrence of the boar taint phenomenon that results from high concentrations of steroids such as androstenone. This topic is also examined in this review
- …