Crustacean cardiac ganglion model reveals constraints on morphology and conductances

The crustacean cardiac ganglion (CG) network coordinates the rhythmic contractions of the heart muscle to control the circulation of blood. The network consists of 9 cells, 5 large motor cells (LC1-5) and 4 small endogenous pacemaker cells (SCs). We report a new three-compartmental biophysical model of an LC that is morphologically realistic and includes provision for inputs from the SCs via a gap-junction coupled spike-initiation-zone (SIZ) compartments. To determine physiologically viable LC models in this realistic configuration, maximal conductances in three compartments of an LC are determined by random sampling from a biologically-characterized 9D-parameter space, followed by a three stage rejection protocol that checks for conformity with electrophysiological features from single cell traces. LC models that pass the single cell rejection protocol are then incorporated into a network model which is then used in a final rejection protocol stage. Using disparate experimental data, the study provides hitherto unknown structure-function insights related to the crustacean cardiac ganglion large cell, including predictions about morphology including the role of its SIZ, and the differential roles of active conductances in the three compartments. Further, we extend analyses of emergent conductance relationships and correlations in model neurons relative to their biological counterparts, allowing us to make inferences both with respect to the biological system as well as the implications of the ability to detect such relationships in populations of model neurons going forward.

Prevention of HIV-1 TAT Protein-Induced Peripheral Neuropathy and Mitochondrial Disruption by the Antimuscarinic Pirenzepine

HIV-associated distal sensory polyneuropathy (HIV-DSP) affects about one third of people with HIV and is characterized by distal degeneration of axons. The pathogenesis of HIV-DSP is not known and there is currently no FDA-approved treatment. HIV trans-activator of transcription (TAT) is associated with mitochondrial dysfunction and neurotoxicity in the brain and may play a role in the pathogenesis of HIV-DSP. In the present study, we measured indices of peripheral neuropathy in the doxycycline (DOX)-inducible HIV-TAT (iTAT) transgenic mouse and investigated the therapeutic efficacy of a selective muscarinic subtype-1 receptor (M1R) antagonist, pirenzepine (PZ). PZ was selected as we have previously shown that it prevents and/or reverses indices of peripheral neuropathy in multiple disease models. DOX alone induced weight loss, tactile allodynia and paw thermal hypoalgesia in normal C57Bl/6J mice. Conduction velocity of large motor fibers, density of small sensory nerve fibers in the cornea and expression of mitochondria-associated proteins in sciatic nerve were unaffected by DOX in normal mice, whereas these parameters were disrupted when DOX was given to iTAT mice to induce TAT expression. Daily injection of PZ (10 mg/kg s.c.) prevented all of the disorders associated with TAT expression. These studies demonstrate that TAT expression disrupts mitochondria and induces indices of sensory and motor peripheral neuropathy and that M1R antagonism may be a viable treatment for HIV-DSP. However, some indices of neuropathy in the DOX-inducible TAT transgenic mouse model can be ascribed to DOX treatment rather than TAT expression and data obtained from animal models in which gene expression is modified by DOX should be accompanied by appropriate controls and treated with due caution.

The importance of early and long-lasting medical rehabilitation in patients with brachial plexus injury

Introduction. Brachial plexus lesions vary in severity, depending on the etiopathogenic mechanism and the level of force to which the plexus is exposed. In the same patient, several nerves of the plexus can be damaged in varying degrees of severity. Brachial plexus injuries lead to upper limb paralysis and disability. Material and Methods. We present the case of a 68-year-old woman diagnosed a year ago with multiple myeloma, clavicular plasmacytoma and secondary spontaneous clavicle fracture. At the same time she presented several dislocations of the shoulder and was diagnosed with brachial plexus palsy after the last dislocation. The patient was hospitalized in our department with a large motor deficit in the upper limb. A comprehensive motor rehabilitation program has been established three weeksafter installing the palsy. Results and discussion. The evolution of the patient was favorable. It was noticed the reduction of the symptoms and slight improvement in motor deficit of the affected upper limb. Thepatient rehabilitation should continue for several months because the nerve regenerates slowly. Conclusion. In patients with brachial plexus injury, motor rehabilitation should be instituted as early as possible and continued for a longer periodoftime until nerve regeneration occurs.It results that early and continuous medical rehabilitation is essential in patients with brachial plexus injury. Keywords: Brachial plexus injury, shoulder dislocation, rehabilitation,

When Slick is Not Smooth: Bottom-Hole Assembly Selection and Its Impact on Wellbore Quality

Appropriate selection of a bottom-hole assembly (BHA) is critical to the success of a drilling operation. In US Land drilling, these assemblies are often selected using local heuristics rather than rigorous analysis. These heuristics are frequently derived from the incentives of the directional contractor as opposed to incentives for the operator. Large motor bends enable more rotation though the curve and reduce the possibility of tripping for build rates. Unstabilized motors are believed to aid sliding and tool face control. Both of these practices lead to drilling a more tortuous wellbore and may cause problems later in the well’s life. This study quantifies the impact of these practices and proposes alternatives that can balance the needs of directional companies with the desire of operators for high-quality wellbores. Over 60 conventional motor assemblies used to drill curves in the Eagle Ford and Permian were analyzed for directional performance using commercial drillstring analysis software. The sliding and rotary tendencies were modelled through the curve across a range of potential drilling conditions. Expected build-rate models were validated by comparison to the maximum achieved doglegs in the directional surveys. When available, additional validation was performed using motor yields calculated from slide sheets. The validated models were compared to the dogleg severity requirements for each assembly’s respective well plan. Comparisons of slide ratios and slide/rotate tendencies of the BHAs were used to estimate the impact on wellbore quality using the tortuosity metric proposed by Jamieson (2019). Typical well plans for both basins had curves of 10 degrees/100ft with no well plan greater than 12 degrees/100ft. Typical bottom hole assemblies were capable of >15 degrees/100ft under normal sliding conditions, with some assemblies capable of >20 degrees/100ft of build. Predicted build rates were validated by slide sheets and observed dogleg severities. Common characteristics among assemblies with excess capacity were high bend angles (>=2 degrees) and minimal stabilization. These slick assemblies also had a strong drop tendency in rotation at low inclinations. The combination of high-build rate with rotary drop greatly increases tortuosity, particularly in the early stages of well. A minority of the assemblies used a lower motor bend angle (<2 degrees) combined with multiple stabilizers. These assemblies had a more consistent directional capability throughout the curve and held angle in rotation. The success of these assemblies confirms that a higher quality wellbore with an improved BHA design is technically achievable. As increasing attention is afforded to the topic of wellbore quality it is important to have methods available to technically achieve high-quality wellbores. In addition to the management of drilling practices, it is also important to have an appropriate BHA design that can enable those practices

EŞİTMƏ QÜSURLU UŞAQLARDA SƏS TƏLƏFFÜZÜ POZULMALARINI ARADAN QALDIRMAQ ÜÇÜN MUSİQİLİ RİTMİK VASİTƏLƏRDƏN İSTİFADƏ

One of the most relevant methods used in the rehabilitation of hearing-impaired children and for the development of speech is music-rhythm. In any games based on music-rhythm, it is possible to stimulate several areas, such as speech, motor, cognitive processes. Composing tasks in the form of role-playing games appropriate to the age characteristics of children increases its effectiveness. Music primarily affects the auditory analyzer in children, helps to increase auditory attention in children with dementia. Thus, the child perceives sounds better over time and develops the ability to differentiate them. Improved hearing allows children to understand the speech of adults better. Over time, it accelerates the process of sound imitation, allows the child to pronounce the initial sounds and syllables. Musical-rhythmic is based on the combination of sounds with movements, which leads to the improvement of children's motor skills. It helps to develop small and large motor skills, rhythm and coordination abilities during tasks. Key words: hearing, speech, game, music, exercise, child

The knowns and unknowns of neural adaptations to resistance training

The initial increases in force production with resistance training are thought to be primarily underpinned by neural adaptations. This notion is firmly supported by evidence displaying motor unit adaptations following resistance training; however, the precise locus of neural adaptation remains elusive. The purpose of this review is to clarify and critically discuss the literature concerning the site(s) of putative neural adaptations to short-term resistance training. The proliferation of studies employing non-invasive stimulation techniques to investigate evoked responses have yielded variable results, but generally support the notion that resistance training alters intracortical inhibition. Nevertheless, methodological inconsistencies and the limitations of techniques, e.g. limited relation to behavioural outcomes and the inability to measure volitional muscle activity, preclude firm conclusions. Much of the literature has focused on the corticospinal tract; however, preliminary research in non-human primates suggests reticulospinal tract is a potential substrate for neural adaptations to resistance training, though human data is lacking due to methodological constraints. Recent advances in technology have provided substantial evidence of adaptations within a large motor unit population following resistance training. However, their activity represents the transformation of afferent and efferent inputs, making it challenging to establish the source of adaptation. Whilst much has been learned about the nature of neural adaptations to resistance training, the puzzle remains to be solved. Additional analyses of motoneuron firing during different training regimes or coupling with other methodologies (e.g., electroencephalography) may facilitate the estimation of the site(s) of neural adaptations to resistance training in the future.

Exploring the Limitations of Event-Related Potential Measures in Moving Subjects: Pilot Studies of Four Different Technical Modifications in Ergometer Rowing

Measuring brain activity in moving subjects is of great importance for investigating human behavior in ecological settings. For this purpose, EEG measures are applicable; however, technical modifications are required to reduce the typical massive movement artefacts. Four different approaches to measure EEG/ERPs during rowing were tested: (i) a purpose-built head-mounted preamplifier, (ii) a laboratory system with active electrodes, and a wireless headset combined with (iii) passive or (iv) active electrodes. A standard visual oddball task revealed very similar (within subjects) visual evoked potentials for rowing and rest (without movement). The small intraindividual differences between rowing and rest, in comparison to the typically larger interindividual differences in the ERP waveforms, revealed that ERPs can be measured reliably even in an athletic movement such as rowing. On the other hand, the expected modulation of the motor-related activity by force output was largely affected by movement artefacts. Therefore, for a successful application of ERP measures in movement research, further developments to differentiate between movement-related neuronal activity and movement-related artefacts are required. However, activities with small magnitudes related to motor learning and motor control may be difficult to detect because they are superimposed by the very large motor potential, which increases with force output.

The “Exo hand-2” complex in the rehabilitation of the upper limb in cerebral palsy using the non-invasive interface “brain-computer”

Improving the function of the upper limb in cerebral palsy is one of the main tasks of rehabilitation treatment and socialization of the patient.The purpose of the study was to evaluate the effectiveness of the “Exo hand-2” complex with the non-invasive interface “brain-computer” for correcting the motor function of the upper limb in cerebral palsy.The study involved 50 male and female with cerebral palsy (main group n = 30, control group n = 20) aged 12–18 years old. The level of motor activity according to the criteria of classification of large motor functions (GMFCS) was not more than III. All patients received a standard course of spa rehabilitation for 21 days. Patients of the main group were additionally rehabilitated using the “Exo hand-2” complex with the non-invasive interface “brain-computer”. As a result of treatment in the main group, spasticity in the paretic hand on the Modified Ashworth Scale decreased from 3 (2; 3) to 2 (1; 2) points (p <0.002); according to Tardieu, spasticity decreased from the level of 3 (2; 3) to 2 (1; 2) (p <0.002). Half of the patients had paretic arm muscle strength in the Medical Research Counsil Weakness Scale sums core from 2.3 (2; 3) to 3 (2; 3) points after treatment (p = 0.002); assessment of household skills on the Modified Franchay Scale showed an improvement from 37 (22.75; 63.75) to 45 (30; 72.75) points after therapy.

Aspects concerning the influence of the design of flameproof electric motors on maximum explosion pressures

The research carried out in the specialized Laboratory of the National Institute for Research and Development in Mine Safety and Explosion Protection INSEMEX Petrosani has identified as causes for the occurrence of high pressure peaks in the case of electric motor enclosures, the internal volume, the geometrical shape of motor enclosures and the very intricate and complex internal arrangement of such motor enclosures (especially in the case of large motor enclosures), having in mind the tendency of motor manufacturers for chemical and petrochemical industry to manufacture motors having more complex geometrical shapes.